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Sample records for acid bacteria yeasts

  1. Lactic acid bacteria and yeasts involved in the fermentation ofamabere amaruranu, a Kenyan fermented milk.

    PubMed

    Nyambane, Bitutu; Thari, William M; Wangoh, John; Njage, Patrick M K

    2014-11-01

    Indigenous fermented milk products contain microbiota composed of technologically important species and strains which are gradually getting lost with new technologies. We investigated the microbial diversity inamabere amaruranu, a traditionally fermented milk product from Kenya. Sixteen samples of the product from different containers were obtained. One hundred and twenty isolates of lactic acid bacteria (LAB) and 67 strains of yeasts were identified using API 50 CH and API 20 C AUX identification kits, respectively. The average pH of all the traditional fermented samples was 4.00 ± 0.93. Lactobacilli, yeasts, and molds as well asEnterobacteriaceae counts from the plastic containers were significantly higher (P < 0.05) than those from gourd.Enterobacteriaceae were below 1.00 ± 1.11 log10 cfu/mL in products from the gourds and 2.17 ± 1.92 log10 cfu/mL from the plastic containers. The LAB species were identified asStreptococcus thermophilus (25%),Lactobacillus plantarum (20%), andLeuconostoc mesenteroides (20%). The predominant yeasts wereSaccharomyces cerevisiae (25%),Trichosporum mucoides (15%),Candida famata (10%), andCandida albicans (10%). The type of vessel used for fermentation had no significant influence on the type of isolated and identified species. The diverse mixture of LAB and yeasts microflora forms a potential consortium for further product innovation inamabere amaruranu and other fermented milk products. PMID:25493187

  2. House microbiotas as sources of lactic acid bacteria and yeasts in traditional Italian sourdoughs.

    PubMed

    Minervini, Fabio; Lattanzi, Anna; De Angelis, Maria; Celano, Giuseppe; Gobbetti, Marco

    2015-12-01

    This study aimed at understanding the extent of contamination by lactic acid bacteria (LAB) and yeasts from the house microbiotas during sourdough back-slopping. Besides sourdoughs, wall, air, storage box, dough mixer and flour of four bakeries were analyzed. Based on plate counts, LAB and yeasts dominated the house microbiota. Based on high throughput sequencing of the 16S rRNA genes, flour harbored the highest number of Firmicutes, but only few of them adapted to storage box, dough mixer and sourdough. Lactobacillus sanfranciscensis showed the highest abundance in dough mixer and sourdoughs. Lactobacillus plantarum persisted only in storage box, dough mixer and sourdough of two bakeries. Weissella cibaria also showed higher adaptability in sourdough than in bakery equipment, suggesting that flour is the main origin of this species. Based on 18S rRNA data, Saccharomyces cerevisiae was the dominant yeast in house and sourdough microbiotas, excepted one bakery dominated by Kazachstania exigua. The results of this study suggest that the dominant species of sourdough LAB and yeasts dominated also the house microbiota. PMID:26338118

  3. Biodiversity of yeasts, lactic acid bacteria and acetic acid bacteria in the fermentation of "Shanxi aged vinegar", a traditional Chinese vinegar.

    PubMed

    Wu, Jia Jia; Ma, Ying Kun; Zhang, Fen Fen; Chen, Fu Sheng

    2012-05-01

    Shanxi aged vinegar is a famous traditional Chinese vinegar made from several kinds of cereal by spontaneous solid-state fermentation techniques. In order to get a comprehensive understanding of culturable microorganism's diversity present in its fermentation, the indigenous microorganisms including 47 yeast isolates, 28 lactic acid bacteria isolates and 58 acetic acid bacteria isolates were recovered in different fermenting time and characterized based on a combination of phenotypic and genotypic approaches including inter-delta/PCR, PCR-RFLP, ERIC/PCR analysis, as well as 16S rRNA and 26S rRNA partial gene sequencing. In the alcoholic fermentation, the dominant yeast species Saccharomyces (S.) cerevisiae (96%) exhibited low phenotypic and genotypic diversity among the isolates, while Lactobacillus (Lb.) fermentum together with Lb. plantarum, Lb. buchneri, Lb. casei, Pediococcus (P.) acidilactici, P. pentosaceus and Weissella confusa were predominated in the bacterial population at the same stage. Acetobacter (A.) pasteurianus showing great variety both in genotypic and phenotypic tests was the dominant species (76%) in the acetic acid fermentation stage, while the other acetic acid bacteria species including A. senegalensis, A. indonesiensis, A. malorum and A. orientalis, as well as Gluconobacter (G.) oxydans were detected at initial point of alcoholic and acetic acid fermentation stage respectively. PMID:22265314

  4. Simultaneous and successive inoculations of yeasts and lactic acid bacteria on the fermentation of an unsulfited Tannat grape must

    PubMed Central

    Muñoz, Viviana; Beccaria, Bruno; Abreo, Eduardo

    2014-01-01

    Interactions between yeasts and lactic acid bacteria are strain specific, and their outcome is expected to change in simultaneous alcoholic - malolactic fermentations from the pattern observed in successive fermentations. One Oenococcus oeni strain Lalvin VP41™ was inoculated with two Saccharomyces cerevisiae strains either simultaneously, three days after the yeast inoculation, or when alcoholic fermentation was close to finish. Early bacterial inoculations with each yeast strain allowed for the growth of the bacterial populations, and the length of malolactic fermentation was reduced to six days. Alcoholic fermentation by Lalvin ICV D80® yeast strain left the highest residual sugar, suggesting a negative effect of the bacterial growth and malolactic activity on its performance. In sequential inoculations the bacterial populations did not show actual growth with either yeast strain. In this strategy, both yeast strains finished the alcoholic fermentations, and malolactic fermentations took longer to finish. Lalvin ICV D80® allowed for higher viability and activity of the bacterial strain than Fermicru UY4® under the three inoculation strategies. This was beneficial for the sequential completion of both fermentations, but negatively affected the completion of alcoholic fermentation by Lalvin ICV D80® in the early bacteria additions. Conversely, Fermicru UY4®, which was rather inhibitory towards the bacteria, favored the timely completion of both fermentations simultaneously. As bacteria in early inoculations with low or no SO2 addition can be expected to multiply and interact with fermenting yeasts, not only are the yeast-bacterium strains combination and time point of the inoculation to be considered, but also the amount of bacteria inoculated. PMID:24948914

  5. Biodiversity of lactic acid bacteria and yeasts in spontaneously-fermented buckwheat and teff sourdoughs.

    PubMed

    Moroni, Alice V; Arendt, Elke K; Dal Bello, Fabio

    2011-05-01

    In this study, four different laboratory scale gluten-free (GF) sourdoughs were developed from buckwheat or teff flours. The fermentations were initiated by the spontaneous biota of the flours and developed under two technological conditions (A and B). Sourdoughs were propagated by continuous back-slopping until the stability was reached. The composition of the stable biota occurring in each sourdough was assessed using both culture-dependent and -independent techniques. Overall, a broad spectrum of lactic acid bacteria (LAB) and yeasts species, belonging mainly to the genera Lactobacillus, Pediococcus, Leuconostoc, Kazachstania and Candida, were identified in the stable sourdoughs. Buckwheat and teff sourdoughs were dominated mainly by obligate or facultative heterofermentative LAB, which are commonly associated with traditional wheat or rye sourdoughs. However, the spontaneous fermentation of the GF flours resulted also in the selection of species which are not consider endemic to traditional sourdoughs, i.e. Pediococcus pentosaceus, Leuconostoc holzapfelii, Lactobacillus gallinarum, Lactobacillus vaginalis, Lactobacillus sakei, Lactobacillus graminis and Weissella cibaria. In general, the composition of the stable biota was strongly affected by the fermentation conditions, whilst Lactobacillus plantarum dominated in all buckwheat sourdoughs. Lactobacillus pontis is described for the first time as dominant species in teff sourdough. Among yeasts, Saccharomyces cerevisiae and Candida glabrata dominated teff sourdoughs, whereas the solely Kazachstania barnetti was isolated in buckwheat sourdough developed under condition A. This study allowed the identification and isolation of LAB and yeasts species which are highly competitive during fermentation of buckwheat or teff flours. Representatives of these species can be selected as starters for the production of sourdough destined to GF bread production. PMID:21356457

  6. Molecular identification and physiological characterization of yeasts, lactic acid bacteria and acetic acid bacteria isolated from heap and box cocoa bean fermentations in West Africa.

    PubMed

    Visintin, Simonetta; Alessandria, Valentina; Valente, Antonio; Dolci, Paola; Cocolin, Luca

    2016-01-01

    Yeast, lactic acid bacteria (LAB) and acetic acid bacteria (AAB) populations, isolated from cocoa bean heap and box fermentations in West Africa, have been investigated. The fermentation dynamicswere determined by viable counts, and 106 yeasts, 105 LAB and 82 AAB isolateswere identified by means of rep-PCR grouping and sequencing of the rRNA genes. During the box fermentations, the most abundant species were Saccharomyces cerevisiae, Candida ethanolica, Lactobacillus fermentum, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii, while S. cerevisiae, Schizosaccharomyces pombe, Hanseniaspora guilliermondii, Pichia manshurica, C. ethanolica, Hanseniaspora uvarum, Lb. fermentum, Lb. plantarum, A. pasteurianus and Acetobacter lovaniensis were identified in the heap fermentations. Furthermore, the most abundant species were molecularly characterized by analyzing the rep-PCR profiles. Strains grouped according to the type of fermentations and their progression during the transformation process were also highlighted. The yeast, LAB and AAB isolates were physiologically characterized to determine their ability to grow at different temperatures, as well as at different pH, and ethanol concentrations, tolerance to osmotic stress, and lactic acid and acetic acid inhibition. Temperatures of 45 °C, a pH of 2.5 to 3.5, 12% (v/v) ethanol and high concentrations of lactic and acetic acid have a significant influence on the growth of yeasts, LAB and AAB. Finally, the yeastswere screened for enzymatic activity, and the S. cerevisiae, H. guilliermondii, H. uvarumand C. ethanolica species were shown to possess several enzymes that may impact the quality of the final product. PMID:26425801

  7. Metabolic activity and symbiotic interactions of lactic acid bacteria and yeasts isolated from water kefir.

    PubMed

    Stadie, Jasmin; Gulitz, Anna; Ehrmann, Matthias A; Vogel, Rudi F

    2013-09-01

    Water kefir is a mildly sour and alcoholic drink fermented by a stable microbial multispecies community. With its high sugar content and low amino acid concentration water kefir medium represents a demanding habitat. In this ecological niche only well adapted microorganisms which are fit to the consortium are able to grow and mutually provide essential nutrients. The synergism between main representatives of water kefir yeasts and lactobacilli was studied in a co-culture model system. Co-cultivation of yeasts and lactobacilli in water kefir medium significantly increased cell yield of all interaction partners, delineating the interaction of these water kefir isolates as mutualism. The support of Zygotorulaspora (Z.) florentina was due to the acidification of the medium by the lactobacilli, whereas lactobacilli are improved in growth by the disposal of essential nutrients produced by yeasts. The trophic interaction between Lactobacillus (Lb.) hordei and yeasts is constituted by the release of amino acids and Vitamin B6 from yeasts, whereas Lb. nagelii is supported in growth by their production of amino acids. The interaction of Z. florentina and Lb. nagelii was further examined to reveal that co-cultivation induced the yeast to release arginine, which was essential for Lb. nagelii. PMID:23664259

  8. ACID-FAST BACTERIA AND YEASTS AS INDICATORS OF DISINFECTION EFFICIENCY

    EPA Science Inventory

    Since the coliform group of organisms is considered to be less resistant to chlorine than some bacterial and viral pathogens, the utility of both yeast and acid-fast oganisms as potntial indicators of disinfection efficiency was evaluated. In most laboratory studies these two gro...

  9. Formation of lactic acid bacteria-yeasts communities on the olive surface during Spanish-style Manzanilla fermentations.

    PubMed

    Arroyo-López, F N; Bautista-Gallego, J; Domínguez-Manzano, J; Romero-Gil, V; Rodriguez-Gómez, F; García-García, P; Garrido-Fernández, A; Jiménez-Díaz, R

    2012-12-01

    This work examines the formation of poly-microbial communities adhered to the surface of Manzanilla olive fruits processed according to the Spanish style. The experimental design consisted of four pilot fermenters inoculated with four Lactobacillus pentosus strains, plus another fermenter which was not inoculated and fermented spontaneously. Lactic acid bacteria and yeasts were analysed in depth on olive epidermis throughout fermentation by plate count, molecular techniques and scanning electron microscopy. Data show that in all cases high population levels (above 8 log(10) CFU per olive) were reached for both groups of microorganisms at the second week of fermentation and that these counts never fell below 6 log(10) CFU per olive during the 3 months that fermenters were monitored. In situ observation of olive epidermis slices revealed a strong aggregation and adhesion between bacteria and yeasts by the formation of a matrix which embedded the microorganisms. Geotrichum candidum, Pichia galeiformis and Candida sorbosa were the main yeast species isolated from these biofilms at the end of fermentation (confirmed by RFLP analysis of the 5.8S-ITS region), while molecular characterization of lactobacilli isolates by means of RAPD-PCR with primer OPL(5) showed in many cases a high similarity in their banding profiles with the inoculated strains. Results obtained in this survey show the importance of studying the olive epidermis throughout fermentation, because ultimately, olives are ingested by consumers. PMID:22986192

  10. Preservation of acidified cucumbers with a combination of fumaric acid and cinnamaldehyde that target lactic acid bacteria and yeasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The naturally occurring compound, fumaric acid, was evaluated as a potential preservative for the long-term storage of cucumbers. Fumaric acid inhibited growth of lactic acid bacteria (LAB) in an acidified cucumber juice medium model system resembling conditions that could allow preservation of cucu...

  11. Taxonomic and molecular characterization of lactic acid bacteria and yeasts in nunu, a Ghanaian fermented milk product.

    PubMed

    Akabanda, Fortune; Owusu-Kwarteng, James; Tano-Debrah, Kwaku; Glover, Richard L K; Nielsen, Dennis S; Jespersen, Lene

    2013-06-01

    Produced from raw unpasteurized milk, nunu is a spontaneously fermented yoghurt-like product made in Ghana and other parts of West Africa. Despite the importance of nunu in the diet of many Africans, there is currently only limited information available on the microorganisms associated with nunu processing. With the aim of obtaining a deeper understanding of the process and as a first step towards developing starter cultures with desired technological properties for nunu production, a microbiological characterization of nunu processing in three different towns in the Upper East region of Ghana, namely Bolgatanga, Paga and Navrongo, was carried out. Lactic acid bacteria (LAB) and yeasts associated with nunu processing were isolated and identified using a combination of pheno- and genotypic methods including morphological and carbohydrate fermentation tests, (GTG)5-based rep-PCR, multiplex PCR, and 16S and 26S rRNA gene sequencing. The LAB counts during nunu processing increased from 4.5 ± 0.4 log cfu/ml at 0 h to 8.7 ± 1.8 log cfu/ml at 24 h of fermentation while yeasts counts increased from 2.8 ± 1.2 log cfu/ml at 0 h to 5.8 ± 0.5 log cfu/ml by the end of fermentation. Lactobacillus fermentum was the dominant LAB throughout the fermentations with Lactobacillus plantarum and Leuconostoc mesenteroides playing prominent roles during the first 6-8 h of fermentation as well. Less frequently isolated LAB included Lactobacillus helveticus, Enterococcus faecium, Enterococcus italicus, Weissella confusa and a putatively novel Lactococcus spp. The yeasts involved were identified as Candida parapsilosis, Candida rugosa, Candida tropicalis, Galactomyces geotrichum, Pichia kudriavzevii and Saccharomyces cerevisiae with P. kudriavzevii and S. cerevisiae being the dominant yeast species. PMID:23541194

  12. Plant-based Paste Fermented by Lactic Acid Bacteria and Yeast: Functional Analysis and Possibility of Application to Functional Foods.

    PubMed

    Kuwaki, Shinsuke; Nakajima, Nobuyoshi; Tanaka, Hidehiko; Ishihara, Kohji

    2012-01-01

    A plant-based paste fermented by lactic acid bacteria and yeast (fermented paste) was made from various plant materials. The paste was made of fermented food by applying traditional food-preservation techniques, that is, fermentation and sugaring. The fermented paste contained major nutrients (carbohydrates, proteins, and lipids), 18 kinds of amino acids, and vitamins (vitamin A, B1, B2, B6, B12, E, K, niacin, biotin, pantothenic acid, and folic acid). It contained five kinds of organic acids, and a large amount of dietary fiber and plant phytochemicals. Sucrose from brown sugar, used as a material, was completely resolved into glucose and fructose. Some physiological functions of the fermented paste were examined in vitro. It was demonstrated that the paste possessed antioxidant, antihypertensive, antibacterial, anti-inflammatory, anti-allergy and anti-tyrosinase activities in vitro. It was thought that the fermented paste would be a helpful functional food with various nutrients to help prevent lifestyle diseases. PMID:25114554

  13. Plant-based Paste Fermented by Lactic Acid Bacteria and Yeast: Functional Analysis and Possibility of Application to Functional Foods

    PubMed Central

    Kuwaki, Shinsuke; Nakajima, Nobuyoshi; Tanaka, Hidehiko; Ishihara, Kohji

    2012-01-01

    A plant-based paste fermented by lactic acid bacteria and yeast (fermented paste) was made from various plant materials. The paste was made of fermented food by applying traditional food-preservation techniques, that is, fermentation and sugaring. The fermented paste contained major nutrients (carbohydrates, proteins, and lipids), 18 kinds of amino acids, and vitamins (vitamin A, B1, B2, B6, B12, E, K, niacin, biotin, pantothenic acid, and folic acid). It contained five kinds of organic acids, and a large amount of dietary fiber and plant phytochemicals. Sucrose from brown sugar, used as a material, was completely resolved into glucose and fructose. Some physiological functions of the fermented paste were examined in vitro. It was demonstrated that the paste possessed antioxidant, antihypertensive, antibacterial, anti-inflammatory, anti-allergy and anti-tyrosinase activities in vitro. It was thought that the fermented paste would be a helpful functional food with various nutrients to help prevent lifestyle diseases. PMID:25114554

  14. The lactic acid bacteria and yeast microbiota of eighteen sourdoughs used for the manufacture of traditional Italian sweet leavened baked goods.

    PubMed

    Lattanzi, Anna; Minervini, Fabio; Di Cagno, Raffaella; Diviccaro, Annamaria; Antonielli, Livio; Cardinali, Gianluigi; Cappelle, Stefan; De Angelis, Maria; Gobbetti, Marco

    2013-05-15

    The lactic acid bacteria and yeast microbiota of eighteen sourdoughs used for the manufacture of some traditional Italian sweet leavened baked goods were studied through culture-dependent method and pyrosequencing. Flours used for back slopping and sourdoughs were also biochemically characterized. Principal component analysis was applied to explore eventual correlations between process parameters applied during back slopping, some flour nutrients, profile of microbiota, and biochemical characteristics of sourdoughs. The median values of the cell density of lactic acid bacteria and yeasts were 8.05 and 7.03 log CFU/g, respectively. As shown by culture-dependent method, Lactobacillus sanfranciscensis was identified in all the sourdoughs, except for Panaredda and Torcolo di San Costanzo. For eleven sourdoughs, all the lactic acid bacteria isolates were allotted to this species. For Buccellato di Lucca, Mbriagotto, Pandoro, and Nadalin sourdoughs, at least 80% of the isolates was allotted to this species. Other lactic acid bacteria isolated with a relatively high frequence were Lactobacillus plantarum and Leuconostoc citreum. Pyrosequencing confirmed and complemented the culture-dependent approach, detecting L. sanfranciscensis also in Panaredda and Torcolo di San Costanzo sourdoughs. Saccharomyces cerevisiae was identified in all the sourdoughs, except for Mbriagotto, Ciambella di Mosto and Pandolce Genovese. These latter sourdoughs harbored strains of Candida humilis, whereas five sourdoughs combined the presence of both yeast species. Positive correlations were found between time of back slopping and cell density and main metabolites of lactic acid bacteria. Percentage of sourdough used as inoculum was mainly correlated with the cell density of yeasts and the concentration of ethanol. This study provided a comprehensive and comparative approach to highlight the dominant microbiota of Italian sourdoughs, which could be exploited further to guarantee a highly

  15. Preservation of acidified cucumbers with a natural preservative combination of fumaric acid and allyl isothiocyanate that target lactic acid bacteria and yeasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Without the addition of preservative compounds cucumbers acidified with 150 mM acetic acid with pH adjusted to 3.5 typically undergo fermentation by lactic acid bacteria. Fumaric acid (20 mM) inhibited growth of Lactobacillus plantarum and the lactic acid bacteria present on fresh cucumbers, but sp...

  16. Optimal Cultivation Time for Yeast and Lactic Acid Bacteria in Fermented Milk and Effects of Fermented Soybean Meal on Rumen Degradability Using Nylon Bag Technique.

    PubMed

    Polyorach, S; Poungchompu, O; Wanapat, M; Kang, S; Cherdthong, A

    2016-09-01

    The objectives of this study were to determine an optimal cultivation time for populations of yeast and lactic acid bacteria (LAB) co-cultured in fermented milk and effects of soybean meal fermented milk (SBMFM) supplementation on rumen degradability in beef cattle using nylon bag technique. The study on an optimal cultivation time for yeast and LAB growth in fermented milk was determined at 0, 4, 8, 24, 48, 72, and 96 h post-cultivation. After fermenting for 4 days, an optimal cultivation time of yeast and LAB in fermented milk was selected and used for making the SBMFM product to study nylon bag technique. Two ruminal fistulated beef cattle (410±10 kg) were used to study on the effect of SBMFM supplementation (0%, 3%, and 5% of total concentrate substrate) on rumen degradability using in situ method at incubation times of 0, 2, 4, 6, 12, 24, 48, and 72 h according to a Completely randomized design. The results revealed that the highest yeast and LAB population culture in fermented milk was found at 72 h-post cultivation. From in situ study, the soluble fractions at time zero (a), potential degradability (a+b) and effective degradability of dry matter (EDDM) linearly (p<0.01) increased with the increasing supplemental levels and the highest was in the 5% SBMFM supplemented group. However, there was no effect of SBMFM supplement on insoluble degradability fractions (b) and rate of degradation (c). In conclusion, the optimal fermented time for fermented milk with yeast and LAB was at 72 h-post cultivation and supplementation of SBMFM at 5% of total concentrate substrate could improve rumen degradability of beef cattle. However, further research on effect of SBMFM on rumen ecology and production performance in meat and milk should be conducted using in vivo both digestion and feeding trials. PMID:26954119

  17. Optimal Cultivation Time for Yeast and Lactic Acid Bacteria in Fermented Milk and Effects of Fermented Soybean Meal on Rumen Degradability Using Nylon Bag Technique

    PubMed Central

    Polyorach, S.; Poungchompu, O.; Wanapat, M.; Kang, S.; Cherdthong, A.

    2016-01-01

    The objectives of this study were to determine an optimal cultivation time for populations of yeast and lactic acid bacteria (LAB) co-cultured in fermented milk and effects of soybean meal fermented milk (SBMFM) supplementation on rumen degradability in beef cattle using nylon bag technique. The study on an optimal cultivation time for yeast and LAB growth in fermented milk was determined at 0, 4, 8, 24, 48, 72, and 96 h post-cultivation. After fermenting for 4 days, an optimal cultivation time of yeast and LAB in fermented milk was selected and used for making the SBMFM product to study nylon bag technique. Two ruminal fistulated beef cattle (410±10 kg) were used to study on the effect of SBMFM supplementation (0%, 3%, and 5% of total concentrate substrate) on rumen degradability using in situ method at incubation times of 0, 2, 4, 6, 12, 24, 48, and 72 h according to a Completely randomized design. The results revealed that the highest yeast and LAB population culture in fermented milk was found at 72 h-post cultivation. From in situ study, the soluble fractions at time zero (a), potential degradability (a+b) and effective degradability of dry matter (EDDM) linearly (p<0.01) increased with the increasing supplemental levels and the highest was in the 5% SBMFM supplemented group. However, there was no effect of SBMFM supplement on insoluble degradability fractions (b) and rate of degradation (c). In conclusion, the optimal fermented time for fermented milk with yeast and LAB was at 72 h-post cultivation and supplementation of SBMFM at 5% of total concentrate substrate could improve rumen degradability of beef cattle. However, further research on effect of SBMFM on rumen ecology and production performance in meat and milk should be conducted using in vivo both digestion and feeding trials. PMID:26954119

  18. Combined moist airtight storage and feed fermentation of barley by the yeast Wickerhamomyces anomalus and a lactic acid bacteria consortium

    PubMed Central

    Borling Welin, Jenny; Lyberg, Karin; Passoth, Volkmar; Olstorpe, Matilda

    2015-01-01

    This study combined moist airtight storage of moist grain with pig feed fermentation. Starter cultures with the potential to facilitate both technologies were added to airtight stored moist crimped cereal grain, and the impact on storage microflora and the quality of feed fermentations generated from the grain was investigated. Four treatments were compared: three based on moist barley, either un-inoculated (M), inoculated with Wickerhamomyces anomalus (W), or inoculated with W. anomalus and LAB starter culture, containing Pediococcus acidilactici DSM 16243, Pediococcus pentosaceus DSM 12834 and Lactobacillus plantarum DSM 12837 (WLAB); and one treatment based on dried barley (D). After 6 weeks of storage, four feed fermentations FM, FW, FWLAB, and FD, were initiated from M, W, WLAB, and D, respectively, by mixing the grain with water to a dry matter content of 30%. Each treatment was fermented in batch initially for 7 days and then kept in a continuous mode by adding new feed daily with 50% back-slop. During the 6 week storage period, the average water activity decreased in M, W and WLAB from 0.96 to 0.85, and cereal pH decreased from approximately 6.0 at harvest to 4.5. Feed fermentation conferred a further pH decrease to 3.8–4.1. In M, W and WLAB, molds and Enterobacteriaceae were mostly below detection limit, whereas both organism groups were detected in D. In fermented feed, Enterobacteriaceae were below detection limit in almost all conditions. Molds were detected in FD, for most of the fermentation time in FM and at some sampling points in FW and FWLAB. Starter organisms, especially W. anomalus and L. plantarum comprised a considerable proportion of the yeast and LAB populations, respectively, in both stored grain and fermented feed. However, autochthonous Pichia kudriavzevii and Kazachstania exigua partially dominated the yeast populations in stored grain and fermented feed, respectively. PMID:25954295

  19. Combined moist airtight storage and feed fermentation of barley by the yeast Wickerhamomyces anomalus and a lactic acid bacteria consortium.

    PubMed

    Borling Welin, Jenny; Lyberg, Karin; Passoth, Volkmar; Olstorpe, Matilda

    2015-01-01

    This study combined moist airtight storage of moist grain with pig feed fermentation. Starter cultures with the potential to facilitate both technologies were added to airtight stored moist crimped cereal grain, and the impact on storage microflora and the quality of feed fermentations generated from the grain was investigated. Four treatments were compared: three based on moist barley, either un-inoculated (M), inoculated with Wickerhamomyces anomalus (W), or inoculated with W. anomalus and LAB starter culture, containing Pediococcus acidilactici DSM 16243, Pediococcus pentosaceus DSM 12834 and Lactobacillus plantarum DSM 12837 (WLAB); and one treatment based on dried barley (D). After 6 weeks of storage, four feed fermentations FM, FW, FWLAB, and FD, were initiated from M, W, WLAB, and D, respectively, by mixing the grain with water to a dry matter content of 30%. Each treatment was fermented in batch initially for 7 days and then kept in a continuous mode by adding new feed daily with 50% back-slop. During the 6 week storage period, the average water activity decreased in M, W and WLAB from 0.96 to 0.85, and cereal pH decreased from approximately 6.0 at harvest to 4.5. Feed fermentation conferred a further pH decrease to 3.8-4.1. In M, W and WLAB, molds and Enterobacteriaceae were mostly below detection limit, whereas both organism groups were detected in D. In fermented feed, Enterobacteriaceae were below detection limit in almost all conditions. Molds were detected in FD, for most of the fermentation time in FM and at some sampling points in FW and FWLAB. Starter organisms, especially W. anomalus and L. plantarum comprised a considerable proportion of the yeast and LAB populations, respectively, in both stored grain and fermented feed. However, autochthonous Pichia kudriavzevii and Kazachstania exigua partially dominated the yeast populations in stored grain and fermented feed, respectively. PMID:25954295

  20. Chlorine dioxide against bacteria and yeasts from the alcoholic fermentation

    PubMed Central

    Meneghin, Silvana Perissatto; Reis, Fabricia Cristina; de Almeida, Paulo Garcia; Ceccato-Antonini, Sandra Regina

    2008-01-01

    The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria (Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration (MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis (10 ppm) and Leuconostoc mesenteroides (50 ppm) than for Lactobacillus fermentum (75 ppm) and Lactobacillus plantarum (125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran® (recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran® dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies (dispersed cells) seemed to be more sensitive than wrinkled yeast colonies (clustered cells/pseudohyphal growth), both isolated from an alcohol-producing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms. PMID:24031227

  1. Interactions between yeasts and bacteria in the smear surface-ripened cheeses.

    PubMed

    Corsetti, A; Rossi, J; Gobbetti, M

    2001-09-19

    In the initial phase of ripening, the microflora of bacterial smear surface-ripened cheeses such as Limburger, Taleggio, Brick, Münster and Saint-Paulin and that of surface mould-ripened cheeses such as Camembert and Brie may be similar, but at the end of the ripening, bacteria such as Brevibacterium spp., Arthrobacter spp., Micrococcus spp., Corynebacterium spp. and moulds such as Penicillium camemberti are, respectively, the dominant microorganisms. Yeasts such as Candida spp., Cryptococcus spp., Debaryomyces spp., Geotrichum candidum, Pichia spp., Rhodotorula spp., Saccharomyces spp. and Yarrowia lipolytica are often and variably isolated from the smear surface-ripened cheeses. Although not dominant within the microorganisms of the smear surface-ripened cheeses, yeasts establish significant interactions with moulds and especially bacteria, including surface bacteria and lactic acid bacteria. Some aspects of the interactions between yeasts and bacteria in such type of cheeses are considered in this paper. PMID:11589547

  2. Modelling the effect of ascorbic acid, sodium metabisulphite and sodium chloride on the kinetic responses of lactic acid bacteria and yeasts in table olive storage using a specifically implemented Quasi-chemical primary model.

    PubMed

    Echevarria, R; Bautista-Gallego, J; Arroyo-López, F N; Garrido-Fernández, A

    2010-04-15

    The goal of this work was to apply the Quasi-chemical primary model (a system of four ordinary differential equations that derives from a hypothetical four-step chemical mechanism involving an antagonistic metabolite) in the study of the evolution of yeast and lactic acid bacteria populations during the storage of Manzanilla-Aloreña table olives subjected to different mixtures of ascorbic acid, sodium metabisulphite and NaCl. Firstly, the Quasi-chemical model was applied to microbial count data to estimate the growth-decay biological parameters. The model accurately described the evolution of both populations during storage, providing detailed information on the microbial behaviour. Secondly, these parameters were used as responses and analysed according to a mixture design experiment (secondary model). The contour lines of the corresponding response surfaces clearly disclosed the relationships between growth and environmental conditions, showing the stimulating and inhibitory effect of ascorbic acid and sodium metabisulphite, respectively, on both populations of microorganisms. This work opens new possibilities for the potential use of the Quasi-chemical primary model in the study of table olive fermentations. PMID:20185187

  3. The effect of lactic acid bacteria on cocoa bean fermentation.

    PubMed

    Ho, Van Thi Thuy; Zhao, Jian; Fleet, Graham

    2015-07-16

    Cocoa beans (Theobroma cacao L.) are the raw material for chocolate production. Fermentation of cocoa pulp by microorganisms is crucial for developing chocolate flavor precursors. Yeasts conduct an alcoholic fermentation within the bean pulp that is essential for the production of good quality beans, giving typical chocolate characters. However, the roles of bacteria such as lactic acid bacteria and acetic acid bacteria in contributing to the quality of cocoa bean and chocolate are not fully understood. Using controlled laboratory fermentations, this study investigated the contribution of lactic acid bacteria to cocoa bean fermentation. Cocoa beans were fermented under conditions where the growth of lactic acid bacteria was restricted by the use of nisin and lysozyme. The resultant microbial ecology, chemistry and chocolate quality of beans from these fermentations were compared with those of indigenous (control) fermentations. The yeasts Hanseniaspora guilliermondii, Pichia kudriavzevii, Kluyveromyces marxianus and Saccharomyces cerevisiae, the lactic acid bacteria Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum and the acetic acid bacteria Acetobacter pasteurianus and Gluconobacter frateurii were the major species found in control fermentations. In fermentations with the presence of nisin and lysozyme, the same species of yeasts and acetic acid bacteria grew but the growth of lactic acid bacteria was prevented or restricted. These beans underwent characteristic alcoholic fermentation where the utilization of sugars and the production of ethanol, organic acids and volatile compounds in the bean pulp and nibs were similar for beans fermented in the presence of lactic acid bacteria. Lactic acid was produced during both fermentations but more so when lactic acid bacteria grew. Beans fermented in the presence or absence of lactic acid bacteria were fully fermented, had similar shell weights and gave acceptable chocolates with no differences

  4. Utilization of hexamethylenetetramine (urotropine) by bacteria and yeasts.

    PubMed

    Middelhoven, Wouter J; van Doesburg, Wim

    2007-02-01

    A slow growing bacterial population able to utilize hexamethylelenetetramine (urotropine) as sole source of carbon, nitrogen and energy was isolated from soil. From this crude enrichment culture two bacteria were isolated and identified as Brevundimonas diminuta and a Phyllobacterium sp. by sequencing of 16S ribosomal DNA. These bacteria also grew on urotropine but at a lower rate than the enrichment culture. Addition of glucose to the latter resulted in growth of some yeasts that overgrew the bacteria. Assimilation of urotropine as sole nitrogen source is very common among yeasts, 46 out of 60 species tested showed this characteristic. PMID:17043911

  5. Electropositively charged filters for the recovery of yeasts and bacteria from beverages.

    PubMed

    Thomas, D S

    1988-07-01

    The ability of electropositively charged filters to recover yeasts and lactic acid bacteria from a variety of beverages was evaluated. Filtration through 'Zeta plus', grade O5S, filters recovered nearly all of the yeast contaminants from table wines, sherry and port. Recovery of yeasts from cream liqueurs and egg-based beverages was also good but it was not possible to filter drinks containing orange juice, even through filters with nominal pore sizes of 2 to 10 micron. Lactic acid bacteria proved more difficult to recover than yeasts, even though smaller pore-sized filters (1 to 4 micron) were employed. However, a sufficiently high percentage of bacteria were recovered to justify use of these filters for quality assurance. The advantage of concentrating contaminants by using charged filters, and the influence of product composition on the efficiency of microbial adsorption are discussed. The growth of wine-spoiling yeasts and lactic acid bacteria were not inhibited by water- or ethanol-soluble extracts of the filter material. PMID:3209514

  6. Influence of autochthonous lactic acid bacteria and enzymatic yeast extracts on the microbiological, biochemical and sensorial properties of Lben generic products.

    PubMed

    Mangia, Nicoletta P; Garau, Giovanni; Murgia, Marco A; Bennani, Abdelmajid; Deiana, Pietrino

    2014-05-01

    In this study we identified Lactococcus lactis subsp. lactis, Lc. lactis subsp. lactis biovar diacetylactis, Kluyveromices lactis and Saccharomyces cerevisiae as the dominant microorganisms of traditional Moroccan acid-alcoholic fermented milk named Lben. The low pH (3·8±0·3), lactose (16·8±3·4 mg/l) and lactic acid (8·16±0·6 mg/l) content indicated that a strong fermentation occurred in the traditional product which was also characterised by the substantial presence of ethanol and typical volatile carbonyl compounds (i.e., acetoin, diacetyl and acetaldehyde). Microbiological analyses of experimental Lben manufactured with selected strains (isolated from the traditional product) of Lc. lactis subsp. lactis and Lc. lactis subsp. lactis biovar. diacetylactis alone (batch A) and in combination with enzymatic extract of a K. lactis strain (batch B) indicated a good effectiveness of the starters employed (∼1010 CFU/g of lactococci after 8 h of incubation) and a significant effect of the yeast enzyme extract on lactococci viability. Despite slight changes in the physicochemical characteristics of the two Lben during the 15 d storage period, volatile compounds (i.e. ethanol, acetaldehyde, diacetyl and acetoin) were consistently higher in batch B. Moreover, sensorial analysis performed after 15 d of storage, highlighted higher odour and flavour intensity, vegetable odour and viscosity in batch B while batch A displayed higher astringency. PMID:24642233

  7. [Quorum sensing in bacteria and yeast].

    PubMed

    March Rosselló, Gabriel Alberto; Eiros Bouza, José María

    2013-10-19

    Bacterial sets are complex dynamic systems, which interact with each other and through the interaction, bacteria coexist, collaborate, compete and share information in a coordinated manner. A way of bacterial communication is quorum sensing. Through this mechanism the bacteria can recognize its concentration in a given environment and they can decide the time at which the expression of a particular set of genes should be started for developing a specific and simultaneous response. The result of these interconnections raises properties that cannot be explained from a single isolated bacterial cell. PMID:23622893

  8. Biopreservation by lactic acid bacteria.

    PubMed

    Stiles, M E

    1996-10-01

    Biopreservation refers to extended storage life and enhanced safety of foods using the natural microflora and (or) their antibacterial products. Lactic acid bacteria have a major potential for use in biopreservation because they are safe to consume and during storage they naturally dominate the microflora of many foods. In milk, brined vegetables, many cereal products and meats with added carbohydrate, the growth of lactic acid bacteria produces a new food product. In raw meats and fish that are chill stored under vacuum or in an environment with elevated carbon dioxide concentration, the lactic acid bacteria become the dominant population and preserve the meat with a "hidden' fermentation. The same applies to processed meats provided that the lactic acid bacteria survive the heat treatment or they are inoculated onto the product after heat treatment. This paper reviews the current status and potential for controlled biopreservation of foods. PMID:8879414

  9. Use of an acidophilic yeast strain to enable the growth of leaching bacteria on solid media.

    PubMed

    Ngom, Baba; Liang, Yili; Liu, Yi; Yin, Huaqun; Liu, Xueduan

    2015-03-01

    In this study, a Candida digboiensis strain was isolated from a heap leaching plant in Zambia and used in double-layer agar plate to efficiently isolate and purify leaching bacteria. Unlike Acidiphilium sp., the yeast strain was tetrathionate tolerant and could metabolize a great range of organic compounds including organic acids. These properties allowed the yeast strain to enable and fasten the growth of iron and sulfur oxidizers on double-layer agar plate. The isolates were identified as Acidithiobacillus ferrooxidans FOX1, Leptospirillun ferriphilum BN, and Acidithiobacillus thiooxidans ZMB. These three leaching bacteria were inhibited by organic acids such as acetic and propionic acids; however, their activities were enhanced by Candida digboiensis NB under dissolved organic matter stress. PMID:25347960

  10. Functional state modelling approach validation for yeast and bacteria cultivations

    PubMed Central

    Roeva, Olympia; Pencheva, Tania

    2014-01-01

    In this paper, the functional state modelling approach is validated for modelling of the cultivation of two different microorganisms: yeast (Saccharomyces cerevisiae) and bacteria (Escherichia coli). Based on the available experimental data for these fed-batch cultivation processes, three different functional states are distinguished, namely primary product synthesis state, mixed oxidative state and secondary product synthesis state. Parameter identification procedures for different local models are performed using genetic algorithms. The simulation results show high degree of adequacy of the models describing these functional states for both S. cerevisiae and E. coli cultivations. Thus, the local models are validated for the cultivation of both microorganisms. This fact is a strong structure model verification of the functional state modelling theory not only for a set of yeast cultivations, but also for bacteria cultivation. As such, the obtained results demonstrate the efficiency and efficacy of the functional state modelling approach. PMID:26740778

  11. Bacteria and yeast microbiota in milk kefir grains from different Italian regions.

    PubMed

    Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Aquilanti, Lucia; De Filippis, Francesca; Stellato, Giuseppina; Di Mauro, Simone; Turchetti, Benedetta; Buzzini, Pietro; Ercolini, Danilo; Clementi, Francesca

    2015-08-01

    Kefir grains are a unique symbiotic association of different microrganisms, mainly lactic acid bacteria, yeasts and occasionally acetic acid bacteria, cohabiting in a natural polysaccharide and a protein matrix. The microbial composition of kefir grains can be considered as extremely variable since it is strongly influenced by the geographical origin of the grains and by the sub-culturing method used. The aim of this study was to elucidate the bacteria and yeast species occurring in milk kefir grains collected in some Italian regions by combining the results of scanning electron microscopy analysis, viable counts on selective culture media, PCR-DGGE and pyrosequencing. The main bacterial species found was Lactobacillus kefiranofaciens while Dekkera anomala was the predominant yeast. The presence of sub-dominant species ascribed to Streptococcus thermophilus, Lactococcus lactis and Acetobacter genera was also highlighted. In addition, Lc. lactis, Enterococcus sp., Bacillus sp., Acetobacter fabarum, Acetobacter lovaniensis and Acetobacter orientalis were identified as part of the cultivable community. This work further confirms both the importance of combining culture-independent and culture-dependent approaches to study microbial diversity in food and how the combination of multiple 16S rRNA gene targets strengthens taxonomic identification using sequence-based identification approaches. PMID:25846922

  12. Challenges to production of antibodies in bacteria and yeast.

    PubMed

    Lee, Yong Jae; Jeong, Ki Jun

    2015-11-01

    Currently, antibodies play major role in treating a wide variety of human diseases (e.g., cancer, viral infection, inflammation). Those pharmaceutic antibodies have become major therapeutic reagents in the pharmaceutical drug market. In addition to full-length antibodies, the market of antibody fragments, which offer potential advantages in clinical use as well as diagnostics, is gradually growing. As the demand for antibody therapeutics increase, the development of host systems for enhanced, and less expensive, production has also become more important. All therapeutic antibodies approved to date are predominantly produced in mammalian hosts, but due to drawbacks such as high production cost and long-term cultivation, the alternative use of bacteria and yeasts has been seriously considered. Recently, there have been reports of substantial progress in genetic engineering and systems biotechnology, results in development of potential hosts that overcame the critical limitations in bacterial and yeast cells, and much enhanced productivity of functional antibodies. In this review, we highlight recent, significant progress made in the engineering of bacterial and yeast cells for enhanced production of functional antibodies. PMID:25912450

  13. The growth, properties and interactions of yeasts and bacteria associated with the maturation of Camembert and blue-veined cheeses.

    PubMed

    Addis, E; Fleet, G H; Cox, J M; Kolak, D; Leung, T

    2001-09-19

    The growth of yeasts and bacteria were monitored during the maturation of Camembert and blue-veined cheese produced in Australia. Yeasts were prominent throughout maturation, growing to 10(5)-10(9)/g, depending on the manufacturer. Debaryomyces hansenii predominated, but there were lesser, inconsistent contributions from Yarrowia lipolytica. Of the non-lactic acid bacteria, Acinetobacter species were significant during the maturation of Camembert but not blue-veined cheeses, and grew to 10(6)-10(8) cfu/g. Staphylococcus and Micrococcus species were consistently isolated from the cheeses with Staphylococcus xylosus growing to 10(5)-10(9) cfu/g, depending on the product. Lactic acid bacteria (10(7)-10(9) cfu/g) were present throughout maturation but were not identified. Interactions between the various yeasts and bacterial isolates were examined. Several strains of D. hansenii exhibited killer activity but not against Y. lipolytica. None of the yeasts were antagonistic towards the bacteria but some strains of D. hansenii enhanced the growth of Y. lipolytica and S. xylosus. The yeast and bacterial isolates exhibited various degrees of extracellular proteolytic and lipolytic activities. PMID:11589557

  14. Lactic acid bacteria from fermented table olives.

    PubMed

    Hurtado, Albert; Reguant, Cristina; Bordons, Albert; Rozès, Nicolas

    2012-08-01

    Table olives are one of the main fermented vegetables in the world. Olives can be processed as treated or natural. Both have to be fermented but treated green olives have to undergo an alkaline treatment before they are placed in brine to start their fermentation. It has been generally established that lactic acid bacteria (LAB) are responsible for the fermentation of treated olives. However, LAB and yeasts compete for the fermentation of natural olives. Yeasts play a minor role in some cases, contributing to the flavour and aroma of table olives and in LAB development. The main microbial genus isolated in table olives is Lactobacillus. Other genera of LAB have also been isolated but to a lesser extent. Lactobacillus plantarum and Lactobacillus pentosus are the predominant species in most fermentations. Factors influencing the correct development of fermentation and LAB, such as pH, temperature, the amount of NaCl, the polyphenol content or the availability of nutrients are also reviewed. Finally, current research topics on LAB from table olives are reviewed, such as using starters, methods of detection and identification of LAB, their production of bacteriocins, and the possibility of using table olives as probiotics. PMID:22475936

  15. Genetics of Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Zagorec, Monique; Anba-Mondoloni, Jamila; Coq, Anne-Marie Crutz-Le; Champomier-Vergès, Marie-Christine

    Many meat (or fish) products, obtained by the fermentation of meat originating from various animals by the flora that naturally contaminates it, are part of the human diet since millenaries. Historically, the use of bacteria as starters for the fermentation of meat, to produce dry sausages, was thus performed empirically through the endogenous micro-biota, then, by a volunteer addition of starters, often performed by back-slopping, without knowing precisely the microbial species involved. It is only since about 50 years that well defined bacterial cultures have been used as starters for the fermentation of dry sausages. Nowadays, the indigenous micro-biota of fermented meat products is well identified, and the literature is rich of reports on the identification of lactic acid bacteria (LAB) present in many traditional fermented products from various geographical origin, obtained without the addition of commercial starters (See Talon, Leroy, & Lebert, 2007, and references therein).

  16. Effects of yeasts and bacteria on the levels of folates in rye sourdoughs.

    PubMed

    Kariluoto, Susanna; Aittamaa, Marja; Korhola, Matti; Salovaara, Hannu; Vahteristo, Liisa; Piironen, Vieno

    2006-02-01

    Fermentation of rye dough is often accompanied with an increase in folate content. In this study, three sourdough yeasts, Candida milleri CBS 8195, Saccharomyces cerevisiae TS 146, and Torulaspora delbrueckii TS 207; a control, baker's yeast S. cerevisiae ALKO 743; and four Lactobacillus spp., L. acidophilus TSB 262, L. brevis TSB 307, L. plantarum TSB 304, and L. sanfranciscensis TSB 299 originally isolated from rye sourdough were examined for their abilities to produce or consume folates. The microorganisms were grown in yeast extract-peptone-d-glucose medium as well as in small-scale fermentations that modelled the sourdough fermentation step used in rye baking. Total folate contents were determined using Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism. The microorganisms studied did not excrete folates into the media in significant amounts. Yeasts increased the folate contents of sterilised rye flour-water mixtures from 6.5 microg/100 g to between 15 and 23 microg/100 g after 19-h fermentation, whereas lactic acid bacteria decreased it to between 2.9 and 4.2 microg/100 g. Strains of Lactobacillus bulgaricus, L. casei, L. curvatus, L. fermentum, L. helveticus, Pediococcus spp., and Streptococcus thermophilus that were also tested gave folate contents after fermentation that varied between 2 and 10.4 microg/100 g. Although the four Lactobacillus spp. from sourdough consumed folates their effect on folate contents in co-cultivations was minimal. It was concluded that the increase of folate content during fermentation was mainly due to folate synthesis by yeasts. Fermentation of non-sterilised flour-water mixtures as such resulted in three-fold increases in the folate contents. Two folate producing bacteria were isolated from the non-sterilised flour and identified as Enterobacter cowanii and Pantoea agglomerans. PMID:16213050

  17. Evidence for PDZ domains in bacteria, yeast, and plants.

    PubMed Central

    Ponting, C. P.

    1997-01-01

    Several dozen signaling proteins are now known to contain 80-100 residue repeats, called PDZ (or DHR or GLGF) domains, several of which interact with the C-terminal tetrapeptide motifs X-Ser/Thr-X-Val-COO- of ion channels and/or receptors. PDZ domains have previously been noted only in mammals, flies, and worms, suggesting that the primordial PDZ domain arose relatively late in eukaryotic evolution. Here, techniques of sequence analysis-including local alignment, profile, and motif database searches-indicate that PDZ domain homologues are present in yeast, plants, and bacteria. It is suggested that two PDZ domains occur in bacterial high-temperature requirement A (htrA) and one in tail-specific protease (tsp) homologues, and that a yeast htrA homologue contains four PDZ domains. Sequence comparisons suggest that the spread of PDZ domains in these diverse organisms may have occurred via horizontal gene transfer. The known affinity of Escherichia coli tsp for C-terminal polypeptides is proposed to be mediated by its PDZ-like domain, in a similar manner to the binding of C-terminal polypeptides by animal PDZ domains. PMID:9041651

  18. Phosphatidic Acid Synthesis in Bacteria

    PubMed Central

    Yao, Jiangwei; Rock, Charles O.

    2012-01-01

    Membrane phospholipid synthesis is a vital facet of bacterial physiology. Although the spectrum of phospholipid headgroup structures produced by bacteria is large, the key precursor to all of these molecules is phosphatidic acid (PtdOH). Glycerol-3-phosphate derived from the glycolysis via glycerol-phosphate synthase is the universal source for the glycerol backbone of PtdOH. There are two distinct families of enzymes responsible for the acylation of the 1-position of glycerol-3-phosphate. The PlsB acyltransferase was discovered in Escherichia coli, and homologs are present in many eukaryotes. This protein family primarily uses acyl-acyl carrier protein (ACP) endproducts of fatty acid synthesis as acyl donors, but may also use acyl-CoA derived from exogenous fatty acids. The second protein family, PlsY, is more widely distributed in bacteria and utilizes the unique acyl donor, acyl-phosphate, which is produced from acyl-ACP by the enzyme PlsX. The acylation of the 2-position is carried out by members of the PlsC protein family. All PlsCs use acyl-ACP as the acyl donor, although the PlsCs of the γ-proteobacteria also may use acyl-CoA. Phospholipid headgroups are precursors in the biosynthesis of other membrane-associated molecules and the diacylglycerol product of these reactions is converted to PtdOH by one of two distinct families of lipid kinases. The central importance of the de novo and recycling pathways to PtdOH in cell physiology suggest these enzymes are suitable targets for the development of antibacterial therapeutics in Gram-positive pathogens. This article is part of a Special Issue entitled Phospholipids and Phospholipid Metabolism. PMID:22981714

  19. Benzo[a]pyrene Uptake by Bacteria and Yeast

    PubMed Central

    Moore, B. G.; Harrison, Arthur P.

    1965-01-01

    Moore, B. G. (Oak Ridge National Laboratory, Oak Ridge, Tenn.), and Arthur P. Harrison, Jr. Benzo[a]pyrene uptake by bacteria and yeast. J. Bacteriol. 90:989–1000. 1965.—Various Enterobacteriaceae and yeast incubated in a medium containing 25 μg/ml of H3-benzo[a]pyrene (30% serum in the medium dissolves the hydrocarbon) retain radioactivity after washings with fresh 30% serum-medium. This radioactivity is defined as bound and represents intact benzo[a]pyrene. Factors relating to the binding of benzo[a]pyrene (benzo[a]pyrene uptake) have been studied in detail with Escherichia coli Ma, a triple auxotroph requiring l-leucine, uracil, and thymine. In defined medium, benzo[a]pyrene uptake by normally growing cells is 10−10 to 2 × 10−10 μg per cell. Uptake is the same in suspensions lacking leucine and containing chloramphenicol where there is neither measurable protein synthesis nor cell division. Uptake is diminished, but not eliminated, by autoclaving the cells; thus, some uptake occurs in the absence of enzymatic activity. Uptake is enhanced by heat shock, thymine deprivation, uracil deprivation, and exposure to penicillin. Thus, uptake is affected by the physiological state of the cells. Either the cells play a direct (enzymatic) role in uptake, or they affect uptake indirectly by increasing or altering the benzo[a]pyrene-binding structure. Physical fractionation of cells demonstrates that this structure is associated with the cell wall-membrane complex. All but 1% of the bound radioactivity is extracted with ethyl alcohol-ether. This residual radioactivity is defined as fixed, and may be associated with cell protein. The extracted radioactivity is identified as benzo[a]pyrene. Very little hydrocarbon is metabolized. Adverse photodynamic effects, increase in mutation, and dimunition in bacteriophage replication (in whole cells) have not been observed in the benzo[a]pyrene cultures. PMID:5321405

  20. Comparative genomics of the lactic acid bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacter...

  1. Decarboxylation of substituted cinnamic acids by lactic acid bacteria isolated during malt whisky fermentation.

    PubMed

    van Beek, S; Priest, F G

    2000-12-01

    Seven strains of Lactobacillus isolated from malt whisky fermentations and representing Lactobacillus brevis, L. crispatus, L. fermentum, L. hilgardii, L. paracasei, L. pentosus, and L. plantarum contained genes for hydroxycinnamic acid (p-coumaric acid) decarboxylase. With the exception of L. hilgardii, these bacteria decarboxylated p-coumaric acid and/or ferulic acid, with the production of 4-vinylphenol and/or 4-vinylguaiacol, respectively, although the relative activities on the two substrates varied between strains. The addition of p-coumaric acid or ferulic acid to cultures of L. pentosus in MRS broth induced hydroxycinnamic acid decarboxylase mRNA within 5 min, and the gene was also induced by the indigenous components of malt wort. In a simulated distillery fermentation, a mixed culture of L. crispatus and L. pentosus in the presence of Saccharomyces cerevisiae decarboxylated added p-coumaric acid more rapidly than the yeast alone but had little activity on added ferulic acid. Moreover, we were able to demonstrate the induction of hydroxycinnamic acid decarboxylase mRNA under these conditions. However, in fermentations with no additional hydroxycinnamic acid, the bacteria lowered the final concentration of 4-vinylphenol in the fermented wort compared to the level seen in a pure-yeast fermentation. It seems likely that the combined activities of bacteria and yeast decarboxylate p-coumaric acid and then reduce 4-vinylphenol to 4-ethylphenol more effectively than either microorganism alone in pure cultures. Although we have shown that lactobacilli participate in the metabolism of phenolic compounds during malt whisky fermentations, the net result is a reduction in the concentrations of 4-vinylphenol and 4-vinylguaiacol prior to distillation. PMID:11097909

  2. Decarboxylation of Substituted Cinnamic Acids by Lactic Acid Bacteria Isolated during Malt Whisky Fermentation

    PubMed Central

    van Beek, Sylvie; Priest, Fergus G.

    2000-01-01

    Seven strains of Lactobacillus isolated from malt whisky fermentations and representing Lactobacillus brevis, L. crispatus, L. fermentum, L. hilgardii, L. paracasei, L. pentosus, and L. plantarum contained genes for hydroxycinnamic acid (p-coumaric acid) decarboxylase. With the exception of L. hilgardii, these bacteria decarboxylated p-coumaric acid and/or ferulic acid, with the production of 4-vinylphenol and/or 4-vinylguaiacol, respectively, although the relative activities on the two substrates varied between strains. The addition of p-coumaric acid or ferulic acid to cultures of L. pentosus in MRS broth induced hydroxycinnamic acid decarboxylase mRNA within 5 min, and the gene was also induced by the indigenous components of malt wort. In a simulated distillery fermentation, a mixed culture of L. crispatus and L. pentosus in the presence of Saccharomyces cerevisiae decarboxylated added p-coumaric acid more rapidly than the yeast alone but had little activity on added ferulic acid. Moreover, we were able to demonstrate the induction of hydroxycinnamic acid decarboxylase mRNA under these conditions. However, in fermentations with no additional hydroxycinnamic acid, the bacteria lowered the final concentration of 4-vinylphenol in the fermented wort compared to the level seen in a pure-yeast fermentation. It seems likely that the combined activities of bacteria and yeast decarboxylate p-coumaric acid and then reduce 4-vinylphenol to 4-ethylphenol more effectively than either microorganism alone in pure cultures. Although we have shown that lactobacilli participate in the metabolism of phenolic compounds during malt whisky fermentations, the net result is a reduction in the concentrations of 4-vinylphenol and 4-vinylguaiacol prior to distillation. PMID:11097909

  3. Discrimination of Pigments of Microalgae, Bacteria and Yeasts Using Lightweight Handheld Raman Spectrometers: Prospects for Astrobiology

    NASA Astrophysics Data System (ADS)

    Jehlicka, J.; Osterrothova, K.; Nedbalova, L.; Gunde-Cimerman, N.; Oren, A.

    2014-06-01

    Handheld Raman instrumentation with 532 nm lasers can be used to distinguish carotenoids of autotrophic microalgae, purple sulfur bacteria, halophilic Archaea and pigmented yeasts. Pigments are proposed as biomarkers for astrobiology of Mars.

  4. Glycolic acid production in the engineered yeasts Saccharomyces cerevisiae and Kluyveromyces lactis

    PubMed Central

    2013-01-01

    Background Glycolic acid is a C2 hydroxy acid that is a widely used chemical compound. It can be polymerised to produce biodegradable polymers with excellent gas barrier properties. Currently, glycolic acid is produced in a chemical process using fossil resources and toxic chemicals. Biotechnological production of glycolic acid using renewable resources is a desirable alternative. Results The yeasts Saccharomyces cerevisiae and Kluyveromyces lactis are suitable organisms for glycolic acid production since they are acid tolerant and can grow in the presence of up to 50 g l-1 glycolic acid. We engineered S. cerevisiae and K. lactis for glycolic acid production using the reactions of the glyoxylate cycle to produce glyoxylic acid and then reducing it to glycolic acid. The expression of a high affinity glyoxylate reductase alone already led to glycolic acid production. The production was further improved by deleting genes encoding malate synthase and the cytosolic form of isocitrate dehydrogenase. The engineered S. cerevisiae strain produced up to about 1 g l-1 of glycolic acid in a medium containing d-xylose and ethanol. Similar modifications in K. lactis resulted in a much higher glycolic acid titer. In a bioreactor cultivation with d-xylose and ethanol up to 15 g l-1 of glycolic acid was obtained. Conclusions This is the first demonstration of engineering yeast to produce glycolic acid. Prior to this work glycolic acid production through the glyoxylate cycle has only been reported in bacteria. The benefit of a yeast host is the possibility for glycolic acid production also at low pH, which was demonstrated in flask cultivations. Production of glycolic acid was first shown in S. cerevisiae. To test whether a Crabtree negative yeast would be better suited for glycolic acid production we engineered K. lactis in the same way and demonstrated it to be a better host for glycolic acid production. PMID:24053654

  5. Acetic acid bacteria spoilage of bottled red wine -- a review.

    PubMed

    Bartowsky, Eveline J; Henschke, Paul A

    2008-06-30

    Acetic acid bacteria (AAB) are ubiquitous organisms that are well adapted to sugar and ethanol rich environments. This family of Gram-positive bacteria are well known for their ability to produce acetic acid, the main constituent in vinegar. The oxidation of ethanol through acetaldehyde to acetic acid is well understood and characterised. AAB form part of the complex natural microbial flora of grapes and wine, however their presence is less desirable than the lactic acid bacteria and yeast. Even though AAB were described by Pasteur in the 1850s, wine associated AAB are still difficult to cultivate on artificial laboratory media and until more recently, their taxonomy has not been well characterised. Wine is at most risk of spoilage during production and the presence of these strictly aerobic bacteria in grape must and during wine maturation can be controlled by eliminating, or at least limiting oxygen, an essential growth factor. However, a new risk, spoilage of wine by AAB after packaging, has only recently been reported. As wine is not always sterile filtered prior to bottling, especially red wine, it often has a small resident bacterial population (<10(3) cfu/mL), which under conducive conditions might proliferate. Bottled red wines, sealed with natural cork closures, and stored in a vertical upright position may develop spoilage by acetic acid bacteria. This spoilage is evident as a distinct deposit of bacterial biofilm in the neck of the bottle at the interface of the wine and the headspace of air, and is accompanied with vinegar, sherry, bruised apple, nutty, and solvent like off-aromas, depending on the degree of spoilage. This review focuses on the wine associated AAB species, the aroma and flavour changes in wine due to AAB metabolism, discusses the importance of oxygen ingress into the bottle and presents a hypothesis for the mechanism of spoilage of bottled red wine. PMID:18237809

  6. Effect of Simultaneous Inoculation with Yeast and Bacteria on Fermentation Kinetics and Key Wine Parameters of Cool-Climate Chardonnay

    PubMed Central

    Jussier, Delphine; Dubé Morneau, Amélie; Mira de Orduña, Ramón

    2006-01-01

    Inoculating grape musts with wine yeast and lactic acid bacteria (LAB) concurrently in order to induce simultaneous alcoholic fermentation (AF) and malolactic fermentation (MLF) can be an efficient alternative to overcome potential inhibition of LAB in wines because of high ethanol concentrations and reduced nutrient content. In this study, the simultaneous inoculation of yeast and LAB into must was compared with a traditional vinification protocol, where MLF was induced after completion of AF. For this, two suitable commercial yeast-bacterium combinations were tested in cool-climate Chardonnay must. The time courses of glucose and fructose, acetaldehyde, several organic acids, and nitrogenous compounds were measured along with the final values of other key wine parameters. Sensory evaluation was done after 12 months of storage. The current study could not confirm a negative impact of simultaneous AF/MLF on fermentation success and kinetics or on final wine parameters. While acetic acid concentrations were slightly increased in wines after simultaneous AF/MLF, the differences were of neither practical nor legal significance. No statistically significant differences were found with regard to the final values of pH or total acidity and the concentrations of ethanol, acetaldehyde, glycerol, citric and lactic acids, and the nitrogen compounds arginine, ammonia, urea, citrulline, and ornithine. Sensory evaluation by a semiexpert panel confirmed the similarity of the wines. However, simultaneous inoculation led to considerable reductions in overall fermentation durations. Furthermore, differences of physiological and microbiological relevance were found. Specifically, we report the vinification of “super-dry” wines devoid of glucose and fructose after simultaneous inoculation of yeast and bacteria. PMID:16391046

  7. Comparative genomics of the lactic acid bacteria

    SciTech Connect

    Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O'Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

    2006-06-01

    Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

  8. The Occurrence of Beer Spoilage Lactic Acid Bacteria in Craft Beer Production.

    PubMed

    Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Taccari, Manuela; Aquilanti, Lucia; Clementi, Francesca

    2015-12-01

    Beer is one of the world's most ancient and widely consumed fermented alcoholic beverages produced with water, malted cereal grains (generally barley and wheat), hops, and yeast. Beer is considered an unfavorable substrate of growth for many microorganisms, however, there are a limited number of bacteria and yeasts, which are capable of growth and may spoil beer especially if it is not pasteurized or sterile-filtered as craft beer. The aim of this research study was to track beer spoilage lactic acid bacteria (LAB) inside a brewery and during the craft beer production process. To that end, indoor air and work surface samples, collected in the brewery under study, together with commercial active dry yeasts, exhausted yeasts, yeast pellet (obtained after mature beer centrifugation), and spoiled beers were analyzed through culture-dependent methods and PCR-DGGE in order to identify the contaminant LAB species and the source of contamination. Lactobacillus brevis was detected in a spoiled beer and in a commercial active dry yeast. Other LAB species and bacteria ascribed to Staphylococcus sp., Enterobaceriaceae, and Acetobacter sp. were found in the brewery. In conclusion, the PCR-DGGE technique coupled with the culture-dependent method was found to be a useful tool for identifying the beer spoilage bacteria and the source of contamination. The analyses carried out on raw materials, by-products, final products, and the brewery were useful for implementing a sanitization plan to be adopted in the production plant. PMID:26489032

  9. Evaluation of lactic acid bacteria for sourdough fermentation of amaranth.

    PubMed

    Sterr, Yasemin; Weiss, Agnes; Schmidt, Herbert

    2009-11-30

    Spontaneous fermented sourdoughs prepared from five amaranth flours were investigated for the presence of lactic acid bacteria predominating the autochthonous microbiota and thus may be suitable as starter cultures. The doughs were fermented with daily back-slopping on a laboratory scale at 30 degrees C for 10 days. Each day, pH-values and total titratable acidity degrees were determined and samples were analyzed for lactic acid bacteria and yeasts by cultural methods. The identity of the strains was tracked with randomly amplified polymorphic DNA-PCR during fermentation. Taxonomic identity of the strains was revealed by sequence analysis of 16S rDNA. Sugar and organic acid profiles of fermented doughs were determined with HPLC. The strains Lactobacillus plantarum RTa12, L. sakei RTa14, and Pediococcus pentosaceus RTa11 were selected and applied as starters in laboratory scale fermentations. All strains were predominant in repeated experiments, both as single strains and in combination, regardless of the amaranth flour used. The competitiveness of the strains L. plantarum RTa12 and P. pentosaceus RTa11 was characterized in further growth experiments. Both strains facilitated fast declines of pH-values, overgrew the autochthonous microbiota, and allowed stable fermentation characteristics at different temperatures. Thus, the characterized strains may be considered as candidates for amaranth sourdough starter cultures. PMID:19783060

  10. Why engineering lactic acid bacteria for biobutanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Gram-positive Lactic acid bacteria (LAB) are considered attractive biocatalysts for biomass to biofuels for several reasons. They have GRAS (Generally Recognized As Safe) status that are acceptable in food, feed, and medical applications. LAB are fermentative: selected strains are capable of f...

  11. Precision genome engineering in lactic acid bacteria

    PubMed Central

    2014-01-01

    Innovative new genome engineering technologies for manipulating chromosomes have appeared in the last decade. One of these technologies, recombination mediated genetic engineering (recombineering) allows for precision DNA engineering of chromosomes and plasmids in Escherichia coli. Single-stranded DNA recombineering (SSDR) allows for the generation of subtle mutations without the need for selection and without leaving behind any foreign DNA. In this review we discuss the application of SSDR technology in lactic acid bacteria, with an emphasis on key factors that were critical to move this technology from E. coli into Lactobacillus reuteri and Lactococcus lactis. We also provide a blueprint for how to proceed if one is attempting to establish SSDR technology in a lactic acid bacterium. The emergence of CRISPR-Cas technology in genome engineering and its potential application to enhancing SSDR in lactic acid bacteria is discussed. The ability to perform precision genome engineering in medically and industrially important lactic acid bacteria will allow for the genetic improvement of strains without compromising safety. PMID:25185700

  12. A small-scale method for quantitation of carotenoids in bacteria and yeasts.

    PubMed

    Kaiser, Philipp; Surmann, Peter; Vallentin, Gerald; Fuhrmann, Herbert

    2007-07-01

    Microbial carotenoids are difficult to extract because of their embedding into a compact matrix and prominent sensitivity to degradation. Especially for carotenoid analysis of bacteria and yeasts, there is lack of information about capability, precision and recovery of the method used. Accordingly, we investigated feasibility, throughput and validity of a new small-scale method using Micrococcus luteus and Rhodotorula glutinis for testing purposes. For disintegration and extraction, we combined primarily mild techniques: enzymatically we used combinations of lysozyme and lipase for bacteria as well as lyticase and lipase for yeasts. Additional mechanical treatment included sonication and freeze-thawing cycles. Chemical treatment with dimethylsulfoxide was applied for yeasts only. For extraction we used a methanol-chloroform mixture stabilized efficiently with butylated hydroxytoluene and alpha-tocopherol. Separation of compounds was achieved with HPLC, applying a binary methanol/tert-butyl methyl ether gradient on a polymer reversed C30 phase. Substances of interest were detected and identified applying a photodiode-array (PDA) and carotenoids quantitated as all-trans-beta-carotene equivalents. For evaluation of recovery and reproducibility of the extraction method, we used beta-8'-apo-carotenal as internal standard. The method provides a sensitive tool for the determination of carotenoids from bacteria and yeasts and also for small changes in carotenoid spectrum of a single species. Corequisite large experiments are facilitated by the high throughput of the method. PMID:17509707

  13. Nectar bacteria, but not yeast, weaken a plant–pollinator mutualism

    PubMed Central

    Vannette, Rachel L.; Gauthier, Marie-Pierre L.; Fukami, Tadashi

    2013-01-01

    Mutualistic interactions are often subject to exploitation by species that are not directly involved in the mutualism. Understanding which organisms act as such ‘third-party’ species and how they do so is a major challenge in the current study of mutualistic interactions. Here, we show that even species that appear ecologically similar can have contrasting effects as third-party species. We experimentally compared the effects of nectar-inhabiting bacteria and yeasts on the strength of a mutualism between a hummingbird-pollinated shrub, Mimulus aurantiacus, and its pollinators. We found that the common bacterium Gluconobacter sp., but not the common yeast Metschnikowia reukaufii, reduced pollination success, seed set and nectar consumption by pollinators, thereby weakening the plant–pollinator mutualism. We also found that the bacteria reduced nectar pH and total sugar concentration more greatly than the yeasts did and that the bacteria decreased glucose concentration and increased fructose concentration whereas the yeasts affected neither. These distinct changes to nectar chemistry may underlie the microbes' contrasting effects on the mutualism. Our results suggest that it is necessary to understand the determinants of microbial species composition in nectar and their differential modification of floral rewards to explain the mutual benefits that plants and pollinators gain from each other. PMID:23222453

  14. In vivo unnatural amino acid expression in the methylotrophic yeast Pichia pastoris

    SciTech Connect

    Young, Travis; Schultz, Peter G

    2014-02-11

    The invention provides orthogonal translation systems for the production of polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris. Methods for producing polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris are also provided.

  15. Kefir: a symbiotic yeasts-bacteria community with alleged healthy capabilities.

    PubMed

    Lopitz-Otsoa, Fernando; Rementeria, Aitor; Elguezabal, Natalia; Garaizar, Javier

    2006-06-01

    Kefir is a fermented milk beverage. The milk fermentation is achieved by the of kefir grains, a cluster of microorganisms held together by a polysaccharide matrix named kefiran. Kefir grains are an example of symbiosis between yeast and bacteria. They have been used over years to produce kefir, a fermented beverage that is consumed all over the world, although its origin is Caucasian. A vast variety of different species of organisms forming the kefir grains, comprising yeast and bacteria, have been isolated and identified. Kefir is a probiotic food. Probiotics have shown to be beneficial to health, being presently of great interest to the food industry. Kefir has been accredited with antibacterial, antifungal and antitumoural activities among other beneficial attributes. This review includes a critical revision of the microbiological composition of kefir along with its beneficial properties to human health. PMID:16854180

  16. High efficiency recombineering in lactic acid bacteria

    PubMed Central

    van Pijkeren, Jan-Peter; Britton, Robert A.

    2012-01-01

    The ability to efficiently generate targeted point mutations in the chromosome without the need for antibiotics, or other means of selection, is a powerful strategy for genome engineering. Although oligonucleotide-mediated recombineering (ssDNA recombineering) has been utilized in Escherichia coli for over a decade, the successful adaptation of ssDNA recombineering to Gram-positive bacteria has not been reported. Here we describe the development and application of ssDNA recombineering in lactic acid bacteria. Mutations were incorporated in the chromosome of Lactobacillus reuteri and Lactococcus lactis without selection at frequencies ranging between 0.4% and 19%. Whole genome sequence analysis showed that ssDNA recombineering is specific and not hypermutagenic. To highlight the utility of ssDNA recombineering we reduced the intrinsic vancomymycin resistance of L. reuteri >100-fold. By creating a single amino acid change in the d-Ala-d-Ala ligase enzyme we reduced the minimum inhibitory concentration for vancomycin from >256 to 1.5 µg/ml, well below the clinically relevant minimum inhibitory concentration. Recombineering thus allows high efficiency mutagenesis in lactobacilli and lactococci, and may be used to further enhance beneficial properties and safety of strains used in medicine and industry. We expect that this work will serve as a blueprint for the adaptation of ssDNA recombineering to other Gram-positive bacteria. PMID:22328729

  17. A single protocol for extraction of gDNA from bacteria and yeast.

    PubMed

    Vingataramin, Laurie; Frost, Eric H

    2015-03-01

    Guanidine thiocyanate breakage of microorganisms has been the standard initial step in genomic DNA (gDNA) extraction of microbial DNA for two decades, despite the requirement for pretreatments to extract DNA from microorganisms other than Gram-negative bacteria. We report a quick and low-cost gDNA extraction protocol called EtNa that is efficient for bacteria and yeast over a broad range of concentrations. EtNa is based on a hot alkaline ethanol lysis. The solution can be immediately centrifuged to yield a crude gDNA extract suitable for PCR, or it can be directly applied to a silica column for purification. PMID:25757544

  18. Indole-3-acetic acid biosynthetic pathways in the basidiomycetous yeast Rhodosporidium paludigenum.

    PubMed

    Nutaratat, Pumin; Srisuk, Nantana; Arunrattiyakorn, Panarat; Limtong, Savitree

    2016-07-01

    Microorganisms produce plant growth regulators, such as auxins, cytokinins and gibberellins, to promote plant growth. Auxins are a group of compounds with an indole ring that have a positive effect on plant growth. Indole-3-acetic acid (IAA) is a plant growth hormone classified as an indole derivative of the auxin family. IAA biosynthesis pathways have been reported and widely studied in several groups of bacteria. Only a few studies on IAA biosynthesis pathways have been conducted in yeast. This study aimed to investigate IAA biosynthesis pathways in a basidiomycetous yeast (Rhodosporidium paludigenum DMKU-RP301). Investigations were performed both with and without a tryptophan supplement. Indole compound intermediates were detected by gas chromatography-mass spectrometry. Indole-3-lactic acid and indole-3-ethanol were found as a result of the enzymatic reduction of indole-3-pyruvic acid and indole-3-acetaldehyde, in IAA biosynthesis via an indole-3-pyruvic acid pathway. In addition, we also found indole-3-pyruvic acid in culture supernatants determined by high-performance liquid chromatography. Identification of tryptophan aminotransferase activity supports indole-3-pyruvic acid-routed IAA biosynthesis in R. paludigenum DMKU-RP301. We hence concluded that R. paludigenum DMKU-RP301 produces IAA through an indole-3-pyruvic acid pathway. PMID:26899734

  19. Inhibition of ethanol-producing yeast and bacteria by degradation products produced during pre-treatment of biomass.

    PubMed

    Klinke, H B; Thomsen, A B; Ahring, B K

    2004-11-01

    An overview of the different inhibitors formed by pre-treatment of lignocellulosic materials and their inhibition of ethanol production in yeast and bacteria is given. Different high temperature physical pre-treatment methods are available to render the carbohydrates in lignocellulose accessible for ethanol fermentation. The resulting hydrolyzsates contain substances inhibitory to fermentation-depending on both the raw material (biomass) and the pre-treatment applied. An overview of the inhibitory effect on ethanol production by yeast and bacteria is presented. Apart from furans formed by sugar degradation, phenol monomers from lignin degradation are important co-factors in hydrolysate inhibition, and inhibitory effects of these aromatic compounds on different ethanol producing microorganisms is reviewed. The furans and phenols generally inhibited growth and ethanol production rate (Q(EtOH)) but not the ethanol yields (Y(EtOH)) in Saccharomyces cerevisiae. Within the same phenol functional group (aldehyde, ketone, and acid) the inhibition of volumetric ethanol productivity was found to depend on the amount of methoxyl substituents and hence hydrophobicity (log P). Many pentose-utilizing strains Escherichia coli, Pichia stipititis, and Zymomonas mobilis produce ethanol in concentrated hemicellulose liquors but detoxification by overliming is needed. Thermoanaerobacter mathranii A3M3 can grow on pentoses and produce ethanol in hydrolysate without any need for detoxification. PMID:15300416

  20. Experimental Study of Membrane Fouling during Crossflow Microfiltration of Yeast and Bacteria Suspensions: Towards an Analysis at the Microscopic Level

    PubMed Central

    Ben Hassan, Ines; Ennouri, Monia; Lafforgue, Christine; Schmitz, Philippe; Ayadi, Abdelmoneim

    2013-01-01

    Microfiltration of model cell suspensions combining macroscopic and microscopic approaches was studied in order to better understand microbial membrane fouling mechanisms. The respective impact of Saccharomyces cerevisiae yeast and Escherichia coli bacteria on crossflow microfiltration performances was investigated using a multichannel ceramic 0.2 µm membrane. Pure yeast suspensions (5 µm ovoid cells) and mixtures of yeast and bacteria (1 to 2.5 µm rod shape cells) were considered in order to analyse the effect of interaction between these two microorganisms on fouling reversibility. The resistances varied significantly with the concentration and characteristics of the microorganisms. Membrane fouling with pure yeast suspension was mainly reversible. For yeast and bacteria mixed suspensions (6 g L−1 yeast concentration) the increase in bacteria from 0.15 to 0.30 g L−1 increased the percentage of normalized reversible resistance. At 10 g L−1 yeast concentration, the addition of bacteria tends to increase the percentage of normalized irreversible resistance. For the objective of performing local analysis of fouling, an original filtration chamber allowing direct in situ observation of the cake by confocal laser scanning microscopy (CLSM) was designed, developed and validated. This device will be used in future studies to characterize cake structure at the microscopic scale. PMID:24958619

  1. Perspectives of engineering lactic acid bacteria for biotechnological polyol production.

    PubMed

    Monedero, Vicente; Pérez-Martínez, Gaspar; Yebra, María J

    2010-04-01

    Polyols are sugar alcohols largely used as sweeteners and they are claimed to have several health-promoting effects (low-caloric, low-glycemic, low-insulinemic, anticariogenic, and prebiotic). While at present chemical synthesis is the only strategy able to assure the polyol market demand, the biotechnological production of polyols has been implemented in yeasts, fungi, and bacteria. Lactic acid bacteria (LAB) are a group of microorganisms particularly suited for polyol production as they display a fermentative metabolism associated with an important redox modulation and a limited biosynthetic capacity. In addition, LAB participate in food fermentation processes, where in situ production of polyols during fermentation may be useful in the development of novel functional foods. Here, we review the polyol production by LAB, focusing on metabolic engineering strategies aimed to redirect sugar fermentation pathways towards the synthesis of biotechnologically important sugar alcohols such as sorbitol, mannitol, and xylitol. Furthermore, possible approaches are presented for engineering new fermentation routes in LAB for production of arabitol, ribitol, and erythritol. PMID:20180114

  2. Degradation of spent craft brewer’s yeast by caprine rumen hyper ammonia-producing bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spent brewer’s yeast has long been included in ruminant diets as a protein supplement. However, modern craft beers often include more hops (Humulus lupulus L.) compounds than traditional recipes. These compounds include alpha and beta-acids, which are antimicrobial to the rumen hyper ammonia-produci...

  3. Exopolysaccharides from sourdough lactic acid bacteria.

    PubMed

    Galle, Sandra; Arendt, Elke K

    2014-01-01

    The use of sourdough improves the quality and increases the shelf life of bread. The positive effects are associated with metabolites produced by lactic acid bacteria (LAB) during sourdough fermentation, including organic acids, exopolysaccharides (EPS), and enzymes. EPS formed during sourdough fermentation by glycansucrase activity from sucrose influence the viscoelastic properties of the dough and beneficially affect the texture and shelf life (in particular, starch retrogradation) of bread. Accordingly, EPS have the potential to replace hydrocolloids currently used as bread improvers and meet so the consumer demands for a reduced use of food additives. In this review, the current knowledge about the functional aspects of EPS formation by sourdough LAB especially in baking applications is summarized. PMID:24499068

  4. Probiotic Lactic Acid Bacteria and Skin Health.

    PubMed

    Jeong, Ji Hye; Lee, Chang Y; Chung, Dae Kyun

    2016-10-25

    Human skin is the first defense barrier against the external environment, especially microbial pathogens and physical stimulation. Many studies on skin health with Lactic acid bacteria (LAB) have been published for many years, including prevention of skin disease and improvement of skin conditions. LAB, a major group of gram-positive bacteria, are known to be beneficial to human health by acting as probiotics. Recent studies have shown that LAB and their extracts have beneficial effects on maintenance and improvement of skin health. Oral administration of Lactobacillus delbrueckii inhibits the development of atopic disease. In addition, LAB and LAB extracts are known to have beneficial effects on intestinal diseases, with Lactobacillus plantarum having been shown to attenuate IL-10 deficient colitis. In addition to intestinal health, L. plantarum also has beneficial effects on skin. pLTA, which is lipoteichoic acid isolated from L. plantarum, has anti-photoaging effects on human skin cells by regulating the expression matrix meralloprotionase-1 (MMP-1) expression. While several studies have proposed a relationship between diseases of the skin and small intestines, there are currently no published reviews of the effects of LAB for skin health through regulation of intestinal conditions and the immune system. In this review, we discuss recent findings on the effects of LAB on skin health and its potential applications in beauty foods. PMID:26287529

  5. Effect of probiotic bacteria on prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses in vitro.

    PubMed

    van der Mei, H C; Free, R H; Elving, G J; Van Weissenbruch, R; Albers, F W; Busscher, H J

    2000-08-01

    The proliferation of yeasts in the mixed bacterial and fungal biofilms colonising silicone rubber voice prostheses in laryngectomised patients is the main cause of malfunctioning of the valve mechanism on the oesophageal side of the prostheses. Indwelling voice prostheses usually have to be replaced every 3-4 months. The consumption of probiotic bacteria is largely motivated by health claims related to the urogenital and lower digestive tract, but not to the upper digestive tract. The present study examined the influence of probiotic bacteria on the prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses, as formed in a modified Robbins device. Exposure of oropharyngeal biofilms on voice prostheses to suspensions of Bifidobacterium infantis 420 or Enterococcus faecium 603 did not significantly reduce the number of yeasts in the biofilm. However, suspensions of Lactobacillus fermentum B54, L. rhamnosus 744 or L. lactis cremoris SK11 led to a reduction in the number of yeasts harvested from the voice prostheses. Suspensions of L. casei Shirota and Streptococcus thermophilus B significantly reduced the number of yeasts in the biofilm to 39% and 33%, respectively. The reduction brought about in yeast prevalence in the mixed biofilm was greatest by exposure to a suspension of L. lactis 53, with yeast prevalence only 4% of the control. In conclusion, the study demonstrated that the prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses might be controlled by consumption of probiotic bacteria. PMID:10933256

  6. Development of radiation sterilized dip slides for enumerating lactic acid bacteria and total count in foodstuffs

    NASA Astrophysics Data System (ADS)

    Eisenberg, E.; Padova, R.; Kirsch, E.; Weissman, Sh.; Hirshfeld, T.; Shenfeld, A.

    APT agar (APT) used for enumeration of lactic acid bacteria and Plate Count agar (PCA) applied for total count were sterilized by gamma radiation using radiation dose of 10-15 kGy. Radiosterilized PCA and APT modified by adding catalase prior to irradiation, or APT with increased content of yeast extract performed, as well as, the heat sterilized commercial media. Growth performance was evaluated on several strains of microorganisms, as well as, by enumeration of bacteria in food products. Radiosterilization of culture media in final packaging, can be applied to produce dip slide kits containing PCA or APT.

  7. A novel method for comparison of biocidal properties of nanomaterials to bacteria, yeasts and algae.

    PubMed

    Suppi, Sandra; Kasemets, Kaja; Ivask, Angela; Künnis-Beres, Kai; Sihtmäe, Mariliis; Kurvet, Imbi; Aruoja, Villem; Kahru, Anne

    2015-04-01

    Toxicity testing of nanomaterials (NMs) is experimentally challenging because NMs may interfere with test environment and assay components. In this work we propose a simple and reliable method--a 'spot test' to compare biocidal potency of NMs to unicellular microorganisms such as bacteria, yeasts and algae. The assay is straightforward: cells are incubated in deionized water suspensions of NMs for up to 24h and then pipetted as a 'spot' on agarized medium. Altogether seven bacterial strains, yeast and a microalga were tested. CuO, TiO2 and two different Ag NPs, multi-wall C-nanotubes (MWCNTs), AgNO3, CuSO4, 3,5-dichlorophenol, triclosan and H2O2 were analyzed. The biocidal potency of tested substances ranged from 0.1mg/L to >1000 mg/L; whereas, the least potent NMs toward all test species were TiO2 NPs and MWCNTs and most potent Ag and CuO NPs. Based on the similar toxicity pattern of the tested chemicals on the nine unicellular organisms in deionized water we conclude that toxicity mechanism of biocidal chemicals seems to be similar, whatever the organism (bacteria, yeast, alga). Therefore, when the organisms are not 'protected' by their environment that usually includes various organic and inorganic supplements their tolerance to toxicants is chemical- rather than organism-dependent. PMID:25559861

  8. New yeast-based approaches in production of palmitoleic acid.

    PubMed

    Kolouchová, Irena; Sigler, Karel; Schreiberová, Olga; Masák, Jan; Řezanka, Tomáš

    2015-09-01

    Palmitoleic acid is found in certain dairy products and has broad applications in medicine and cosmetics. We tried to find a suitable producer of this acid among traditional biotechnological yeast species (Kluyveromyces polysporus, Torulaspora delbrueckii, Saccharomyces cerevisiae) characterized by high biomass yield and Candida krusei, Yarrowia lipolytica and Trichosporon cutaneum accumulating large amounts of lipids. The main factor affecting the content of palmitoleic acid was found to be the C/N ratio in the culture medium, with ammonium sulfate as an optimum nitrogen source leading to highest biomass yield with concomitantly increased lipid accumulation, and an increased content of ω6-linoleic acid, the precursor of prostaglandins, leukotrienes, and thromboxanes. We found that C. krusei can be conveniently used for the purpose, albeit only under certain cultivation conditions, whereas S. cerevisiae can produce high and stable amounts of palmitoleic acid in a broad range of cultivation conditions ranging from conventional to nutrient limitations. PMID:26101962

  9. Integrated microbioreactor for culture and analysis of bacteria, algae and yeast.

    PubMed

    Au, Sam H; Shih, Steve C C; Wheeler, Aaron R

    2011-02-01

    We introduce a micro-scale bioreactor for automated culture and density analysis of microorganisms. The microbioreactor is powered by digital microfluidics (DMF) and because it is used with bacteria, algae and yeast, we call it the BAY microbioreactor. Previous miniaturized bioreactors have relied on microchannels which often require valves, mixers and complex optical systems. In contrast, the BAY microbioreactor is capable of culturing microorganisms in distinct droplets on a format compatible with conventional bench-top analyzers without the use of valves, mixers or pumps. Bacteria, algae and yeast were grown for up to 5 days with automated semi-continuous mixing and temperature control. Cell densities were determined by measuring absorbances through transparent regions of the devices, and growth profiles were shown to be comparable to those generated in conventional, macro-scale systems. Cell growth and density measurements were integrated in the microbioreactor with a fluorescent viability assay and transformation of bacteria with a fluorescent reporter gene. These results suggest that DMF may be a useful new tool in automated culture and analysis of microorganisms for a wide range of applications. PMID:20838902

  10. Culex pipiens Development Is Greatly Influenced by Native Bacteria and Exogenous Yeast.

    PubMed

    Díaz-Nieto, Leonardo M; D Alessio, Cecilia; Perotti, M Alejandra; Berón, Corina M

    2016-01-01

    Culex pipiens is the most cosmopolitan mosquito of the Pipiens Assemblage. By studying the nature of interactions between this species and microorganisms common to its breeding environment we can unravel important pitfalls encountered during development. We tested the survival rate of larval stages, pupae and adults of a Cx. pipiens colony exposed to a variety of microorganisms in laboratory conditions and assessed the transmission to offspring (F1) by those organisms that secured development up to adulthood. Three complementary experiments were designed to: 1) explore the nutritional value of yeasts and other microorganisms during Cx. pipiens development; 2) elucidate the transstadial transmission of yeast to the host offspring; and 3) to examine the relevance of all these microorganisms in female choice for oviposition-substratum. The yeast Saccharomyces cerevisiae proved to be the most nutritional diet, but despite showing the highest survival rates, vertical transmission to F1 was never confirmed. In addition, during the oviposition trials, none of the gravid females was attracted to the yeast substratum. Notably, the two native bacterial strains, Klebsiella sp. and Aeromonas sp., were the preferred oviposition media, the same two bacteria that managed to feed neonates until molting into 2nd instar larvae. Our results not only suggest that Klebsiella sp. or Aeromonas sp. serve as attractants for oviposition habitat selection, but also nurture the most fragile instar, L1, to assure molting into a more resilient stage, L2, while yeast proves to be the most supportive diet for completing development. These experiments unearthed survival traits that might be considered in the future development of strategies of Cx. pipiens control. These studies can be extended to other members of the Pipiens Assemblage. PMID:27055276

  11. Ecophysiological properties of cultivable heterotrophic bacteria and yeasts dominating in phytocenoses of Galindez Island, maritime Antarctica.

    PubMed

    Vasileva-Tonkova, Evgenia; Romanovskaya, Victoria; Gladka, Galina; Gouliamova, Dilnora; Tomova, Iva; Stoilova-Disheva, Margarita; Tashyrev, Oleksandr

    2014-04-01

    Antarctic plants are stable specific microenvironments for microbial colonization that are still less explored. In this study, we investigated cultivable heterotrophic bacteria and yeasts dominating in plant samples collected from different terrestrial biotopes near Ukrainian Antarctic Base on Galindez Island, maritime Antarctica. Phylogenetic analysis revealed affiliation of the bacterial isolates to genera Pseudomonas, Stenotrophomonas, Brevundimonas, Sporosarcina, Dermacoccus, Microbacterium, Rothia and Frondihabitans, and the yeast isolates to genera Rhodosporidium, Cryptococcus, Leucosporidiella, Candida and Exophiala. Some ecophysiological properties of isolated strains were determined that are important in response to different stresses such as psychro- and halotolerance, UV-resistance and production of hydrolytic enzymes. The majority of isolates (88 %) was found to be psychrotolerant; all are halotolerant. Significant differences in survival subsequent to UV-C radiation were observed among the isolates, as measured by culturable counts. For the bacterial isolates, lethal doses in the range 80-600 J m⁻² were determined, and for the yeast isolates--in the range 300-1,000 J m⁻². Dermacoccus profundi U9 and Candida davisiana U6 were found as most UV resistant among the bacterial and yeast isolates, respectively. Producers of caseinase, gelatinase, β-glucosidase, and cellulase were detected. To the best of our knowledge, this is the first report on isolation of UV resistant strain D. profundi, and Frondihabitans strain from Antarctica, and on detection of cellulase activity in Antarctic yeast strain C. davisiana. The results obtained contribute to clarifying adaptation strategies of Antarctic microbiota and its possible role in functional stability of Antarctic biocenoses. Stress tolerant strains were detected that are valuable for ecological and applied studies. PMID:24277323

  12. Culex pipiens Development Is Greatly Influenced by Native Bacteria and Exogenous Yeast

    PubMed Central

    Díaz-Nieto, Leonardo M.; D´Alessio, Cecilia

    2016-01-01

    Culex pipiens is the most cosmopolitan mosquito of the Pipiens Assemblage. By studying the nature of interactions between this species and microorganisms common to its breeding environment we can unravel important pitfalls encountered during development. We tested the survival rate of larval stages, pupae and adults of a Cx. pipiens colony exposed to a variety of microorganisms in laboratory conditions and assessed the transmission to offspring (F1) by those organisms that secured development up to adulthood. Three complementary experiments were designed to: 1) explore the nutritional value of yeasts and other microorganisms during Cx. pipiens development; 2) elucidate the transstadial transmission of yeast to the host offspring; and 3) to examine the relevance of all these microorganisms in female choice for oviposition-substratum. The yeast Saccharomyces cerevisiae proved to be the most nutritional diet, but despite showing the highest survival rates, vertical transmission to F1 was never confirmed. In addition, during the oviposition trials, none of the gravid females was attracted to the yeast substratum. Notably, the two native bacterial strains, Klebsiella sp. and Aeromonas sp., were the preferred oviposition media, the same two bacteria that managed to feed neonates until molting into 2nd instar larvae. Our results not only suggest that Klebsiella sp. or Aeromonas sp. serve as attractants for oviposition habitat selection, but also nurture the most fragile instar, L1, to assure molting into a more resilient stage, L2, while yeast proves to be the most supportive diet for completing development. These experiments unearthed survival traits that might be considered in the future development of strategies of Cx. pipiens control. These studies can be extended to other members of the Pipiens Assemblage. PMID:27055276

  13. Towards lactic acid bacteria-based biorefineries.

    PubMed

    Mazzoli, Roberto; Bosco, Francesca; Mizrahi, Itzhak; Bayer, Edward A; Pessione, Enrica

    2014-11-15

    Lactic acid bacteria (LAB) have long been used in industrial applications mainly as starters for food fermentation or as biocontrol agents or as probiotics. However, LAB possess several characteristics that render them among the most promising candidates for use in future biorefineries in converting plant-derived biomass-either from dedicated crops or from municipal/industrial solid wastes-into biofuels and high value-added products. Lactic acid, their main fermentation product, is an attractive building block extensively used by the chemical industry, owing to the potential for production of polylactides as biodegradable and biocompatible plastic alternative to polymers derived from petrochemicals. LA is but one of many high-value compounds which can be produced by LAB fermentation, which also include biofuels such as ethanol and butanol, biodegradable plastic polymers, exopolysaccharides, antimicrobial agents, health-promoting substances and nutraceuticals. Furthermore, several LAB strains have ascertained probiotic properties, and their biomass can be considered a high-value product. The present contribution aims to provide an extensive overview of the main industrial applications of LAB and future perspectives concerning their utilization in biorefineries. Strategies will be described in detail for developing LAB strains with broader substrate metabolic capacity for fermentation of cheaper biomass. PMID:25087936

  14. Tracking Diacylglycerol and Phosphatidic Acid Pools in Budding Yeast

    PubMed Central

    Ganesan, Suriakarthiga; Shabits, Brittney N.; Zaremberg, Vanina

    2015-01-01

    Phosphatidic acid (PA) and diacylglycerol (DAG) are key signaling molecules and important precursors for the biosynthesis of all glycerolipids found in eukaryotes. Research conducted in the model organism Saccharomyces cerevisiae has been at the forefront of the identification of the enzymes involved in the metabolism and transport of PA and DAG. Both these lipids can alter the local physical properties of membranes by introducing negative curvature, but the anionic nature of the phosphomonoester headgroup in PA sets it apart from DAG. As a result, the mechanisms underlying PA and DAG interaction with other lipids and proteins are notoriously different. This is apparent from the analysis of the protein domains responsible for recognition and binding to each of these lipids. We review the current evidence obtained using the PA-binding proteins and domains fused to fluorescent proteins for in vivo tracking of PA pools in yeast. In addition, we present original results for visualization of DAG pools in yeast using the C1 domain from mammalian PKCδ. An emerging first cellular map of the distribution of PA and DAG pools in actively growing yeast is discussed. PMID:27081314

  15. Isolation and characterisation of lactic acid bacteria from donkey milk.

    PubMed

    Soto Del Rio, Maria de Los Dolores; Andrighetto, Christian; Dalmasso, Alessandra; Lombardi, Angiolella; Civera, Tiziana; Bottero, Maria Teresa

    2016-08-01

    During the last years the interest in donkey milk has increased significantly mainly because of its compelling functional elements. Even if the composition and nutritional properties of donkey milk are known, its microbiota is less studied. This Research Communication aimed to provide a comprehensive characterisation of the lactic acid bacteria in raw donkey milk. RAPD-PCR assay combined with 16S rDNA sequencing analysis were used to describe the microbial diversity of several donkey farms in the North West part of Italy. The more frequently detected species were: Lactobacillus paracasei, Lactococcus lactis and Carnobacterium maltaromaticum. Less abundant genera were Leuconostoc, Enterococcus and Streptococcus. The yeast Kluyveromyces marxianus was also isolated. The bacterial and biotype distribution notably diverged among the farms. Several of the found species, not previously detected in donkey milk, could have an important probiotic activity and biotechnological potential. This study represents an important insight to the ample diversity of the microorganisms present in the highly selective ecosystem of raw donkey milk. PMID:27600975

  16. Stress Physiology of Lactic Acid Bacteria.

    PubMed

    Papadimitriou, Konstantinos; Alegría, Ángel; Bron, Peter A; de Angelis, Maria; Gobbetti, Marco; Kleerebezem, Michiel; Lemos, José A; Linares, Daniel M; Ross, Paul; Stanton, Catherine; Turroni, Francesca; van Sinderen, Douwe; Varmanen, Pekka; Ventura, Marco; Zúñiga, Manuel; Tsakalidou, Effie; Kok, Jan

    2016-09-01

    Lactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g., Lactococcus lactis), probiotic (e.g., several Lactobacillus spp.), and pathogenic (e.g., Enterococcus and Streptococcus spp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the "stressome" of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance. PMID:27466284

  17. Independent and additive effects of glutamic acid and methionine on yeast longevity.

    PubMed

    Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

    2013-01-01

    It is established that glucose restriction extends yeast chronological and replicative lifespan, but little is known about the influence of amino acids on yeast lifespan, although some amino acids were reported to delay aging in rodents. Here we show that amino acid composition greatly alters yeast chronological lifespan. We found that non-essential amino acids (to yeast) methionine and glutamic acid had the most significant impact on yeast chronological lifespan extension, restriction of methionine and/or increase of glutamic acid led to longevity that was not the result of low acetic acid production and acidification in aging media. Remarkably, low methionine, high glutamic acid and glucose restriction additively and independently extended yeast lifespan, which could not be further extended by buffering the medium (pH 6.0). Our preliminary findings using yeasts with gene deletion demonstrate that glutamic acid addition, methionine and glucose restriction prompt yeast longevity through distinct mechanisms. This study may help to fill a gap in yeast model for the fast developing view that nutrient balance is a critical factor to extend lifespan. PMID:24244480

  18. Influence of Artisan Bakery- or Laboratory-Propagated Sourdoughs on the Diversity of Lactic Acid Bacterium and Yeast Microbiotas

    PubMed Central

    Minervini, Fabio; Lattanzi, Anna; De Angelis, Maria; Gobbetti, Marco

    2012-01-01

    Seven mature type I sourdoughs were comparatively back-slopped (80 days) at artisan bakery and laboratory levels under constant technology parameters. The cell density of presumptive lactic acid bacteria and related biochemical features were not affected by the environment of propagation. On the contrary, the number of yeasts markedly decreased from artisan bakery to laboratory propagation. During late laboratory propagation, denaturing gradient gel electrophoresis (DGGE) showed that the DNA band corresponding to Saccharomyces cerevisiae was no longer detectable in several sourdoughs. Twelve species of lactic acid bacteria were variously identified through a culture-dependent approach. All sourdoughs harbored a certain number of species and strains, which were dominant throughout time and, in several cases, varied depending on the environment of propagation. As shown by statistical permutation analysis, the lactic acid bacterium populations differed among sourdoughs propagated at artisan bakery and laboratory levels. Lactobacillus plantarum, Lactobacillus sakei, and Weissella cibaria dominated in only some sourdoughs back-slopped at artisan bakeries, and Leuconostoc citreum seemed to be more persistent under laboratory conditions. Strains of Lactobacillus sanfranciscensis were indifferently found in some sourdoughs. Together with the other stable species and strains, other lactic acid bacteria temporarily contaminated the sourdoughs and largely differed between artisan bakery and laboratory levels. The environment of propagation has an undoubted influence on the composition of sourdough yeast and lactic acid bacterium microbiotas. PMID:22635989

  19. Process strategies to maximize lipid accumulations of novel yeast in acid and base treated hydrolyzates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oleaginous yeasts can accumulate up to 70% of cell biomass as lipids, predominantly as triacylglycerols. Yeast lipid fatty acid profiles have been reported to be similar to that of vegetable oils and consist primarily of oleic, palmitic, stearic, and linoleic acids. This capability provides the oppo...

  20. D-amino acid oxidase from the yeast Trigonopsis variabilis.

    PubMed

    Kubicek-Pranz, E M; Röhr, M

    1985-04-01

    D-Amino acid oxidase (EC 1.4.3.3) has been purified from the yeast Trigonopsis variabilis by the application of ion-exchange chromatography on DEAE-cellulose, salt precipitation, gel filtration, and hydroxyapatite adsorption. Alternatively the last two steps can be substituted by a single fast protein liquid chromatographic ion-exchange step (Mono Q). The enzyme appeared homogeneous in PAGE, but small amounts of impurities (not exceeding 5% of total protein) appeared in sodium dodecyl sulfate (SDS)-PAGE. Its Mr in SDS-PAGE is 39,000; it exhibits an isoelectric point of 4.8 and contains 7% (w/v) covalently bound carbohydrate. Its absorption spectrum is similar to hog kidney D-amino acid oxidase, indicating the presence of bound FAD, which, however, could not be separated from the enzyme under non-denaturing conditions. The enzyme is inhibited by SH-oxidizing agents, but not by metal-chelate formers and not by benzoate or toluene. It uses O2 exclusively as the only H acceptor. Km and Vmax values were determined for 15 D-amino acids, which, among 23 tested, were substrates of the enzyme. The enzyme has highest affinity for D-phenylalanine and D-leucine, but maximal activity is obtained with D-citrulline and D-isoleucine. The specific activity of the purified preparation is even higher than that of the commercially available hog kidney enzyme (21.7 vs 16 U/mg). The yeast enzyme may be a useful analytical and preparative tool in view of the difference between its substrate specificity and that of the hog enzyme. PMID:2865242

  1. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment.

    PubMed

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta; Ercolini, Danilo

    2015-11-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality. PMID:26341209

  2. Coexistence of Lactic Acid Bacteria and Potential Spoilage Microbiota in a Dairy Processing Environment

    PubMed Central

    Stellato, Giuseppina; De Filippis, Francesca; La Storia, Antonietta

    2015-01-01

    Microbial contamination in food processing plants can play a fundamental role in food quality and safety. In this study, the microbiota in a dairy plant was studied by both 16S rRNA- and 26S rRNA-based culture-independent high-throughput amplicon sequencing. Environmental samples from surfaces and tools were studied along with the different types of cheese produced in the same plant. The microbiota of environmental swabs was very complex, including more than 200 operational taxonomic units with extremely variable relative abundances (0.01 to 99%) depending on the species and sample. A core microbiota shared by 70% of the samples indicated a coexistence of lactic acid bacteria with a remarkable level of Streptococcus thermophilus and possible spoilage-associated bacteria, including Pseudomonas, Acinetobacter, and Psychrobacter, with a relative abundance above 50%. The most abundant yeasts were Kluyveromyces marxianus, Yamadazyma triangularis, Trichosporon faecale, and Debaryomyces hansenii. Beta-diversity analyses showed a clear separation of environmental and cheese samples based on both yeast and bacterial community structure. In addition, predicted metagenomes also indicated differential distribution of metabolic pathways between the two categories of samples. Cooccurrence and coexclusion pattern analyses indicated that the occurrence of potential spoilers was excluded by lactic acid bacteria. In addition, their persistence in the environment can be helpful to counter the development of potential spoilers that may contaminate the cheeses, with possible negative effects on their microbiological quality. PMID:26341209

  3. Treatment of heavy oil wastewater by UASB-BAFs using the combination of yeast and bacteria.

    PubMed

    Zou, Xiao-Ling

    2015-01-01

    A novel system integrating an upflow anaerobic sludge blanket (UASB) reactor and a two-stage biological aerated filter (BAF) system was investigated as advanced treatment of heavy oil wastewater with large amounts of dissolved recalcitrant organic substances and low levels of nitrogen and phosphorus nutrients. #1 BAF, inoculated with two yeast strains (Candida tropicalis and Rhodotorula dairenensis), was installed in the upper reaches of #2 BAF inoculated with activated sludge. During the 180-day study period, the chemical oxygen demand (COD), ammonia nitrogen (NH3-N), oil and polyaromatic hydrocarbons (PAHs) in the wastewater were removed by 90.2%, 90.8%, 86.5% and 89.4%, respectively. Although the wastewater qualities fluctuated and the hydraulic retention time continuously decreased, the effluent quality index met the national discharge standard steadily. The UASB process greatly improved the biodegradability of the wastewater, while #1 BAF played an important role not only in degrading COD but also in removing oil and high molecular weight PAHs. This work demonstrates that the hybrid UASB-BAFs system containing yeast-bacteria consortium has the potential to be used in bioremediation of high-strength oily wastewater. PMID:25783230

  4. Role of selected oxidative yeasts and bacteria in cucumber secondary fermentation associated with spoilage of the fermented fruit

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Changes during the spoilage of fermented cucumber pickles have been attributed to the metabolism of different yeasts and bacteria. In this study six organisms isolated from commercial spoiled cucumber pickles were evaluated for their possible role in primary and secondary cucumber fermentations. The...

  5. Production of Value-added Products by Lactic Acid Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) are a group of facultative anaerobic, catalase negative, nonmotile and nonsporeforming–Gram positive bacteria. Most LAB utilize high energy C sources including monomer sugars to produce energy to maintain cellular structure and function. This anaerobic fermentation proce...

  6. DNA fingerprinting of lactic acid bacteria in sauerkraut fermentations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies using traditional biochemical methods to study the ecology of commercial sauerkraut fermentations revealed that four lactic acid bacteria species, Leuconostoc mesenteroides, Lactobacillus plantarum, Pediococcus pentosaceus, and Lactobacillus brevis were the primary microorganisms in...

  7. Expression of yellow jacket and wasp venom Ag5 allergens in bacteria and in yeast.

    PubMed

    Monsalve, R I; Lu, G; King, T P

    1999-01-01

    Antigen 5 (Ag5), of unknown biological function, is one of the major venom allergens of vespids and fire ants. We have compared the expression of Ag5 in bacteria and in yeast. Recombinant Ag5 from bacteria formed an insoluble intracellular product, which was not properly folded, but that produced in Pichia pastoris was secreted to the extracellular medium. Immunochemical characterizations showed the secreted Ag5 to have the native structure of the natural protein. This is of interest since the B cell epitopes of Ag5 are mainly of the discontinuous type. These studies were made with Ag5s from yellow jacket (Vespula vulgaris) and paper wasp (Polistes annularis), and with hybrid Ag5 molecules that contained partial sequences of these two species. In vitro allergenicity studies with sera from yellow jacket-sensitive patients showed that some of these hybrid molecules had a greatly reduced allergenicity but retained the immunogenicity of the natural allergen. This could be of importance for immunotherapy of this type of allergy. PMID:11487873

  8. Probiotic lactic acid bacteria - the fledgling cuckoos of the gut?

    PubMed

    Berstad, Arnold; Raa, Jan; Midtvedt, Tore; Valeur, Jørgen

    2016-01-01

    It is tempting to look at bacteria from our human egocentric point of view and label them as either 'good' or 'bad'. However, a microbial society has its own system of government - 'microcracy' - and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being 'friendly' - they may instead behave like fledgling cuckoos. PMID:27235098

  9. Effects of heavy metals on the electrokinetic properties of bacteria, yeast, and clay minerals

    SciTech Connect

    Collins, Y.E.

    1987-01-01

    The electrokinetic patterns of four bacteria (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae, Canida albicans), and two clay minerals (montmorillonite, kaolinite) in the presence of the chloride salts of heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) and of Na and Mg were determined by microelectrophoresis. The cells and clays were net negatively charged at pH values above their isoelectric point (pI) in solutions of Na, Mg, Hg, and Pb with an ionic strength (..mu..) of 3 x 10/sup -4/. However, at pH values above pH 5.0, the charge of some bacteria, S. cerevisiae, and kaolinite changed to a net positive charge (charge reversal) in the presence of Cd, Cr, Cu, Ni, and Zn. The charge of the bacteria and S. cerevisiae also reversed in solution of Ni and Cu with a ..mu.. > 3 x 10/sup -4/, whereas there was no reversal in solutions with a ..mu.. < 3 x 10/sup -4/. The clays became net positively charged when the ..mu.. of Cu was > 3 x 10/sup -4/ and that of Ni was > 1.5 x 10/sup -4/. The charge of the cells and clays also reversed in solutions containing both Mg and Ni or both Cu and Ni (except montmorillonite) but not in solutions containing both Mg and Cu (except kaolinite) (..mu.. = 3 x 10/sup -4/). The pI of the cells in the presence of some heavy metals, especially Ni and Cr, was at higher pH values than in the presence of Na and Mg.

  10. Temperature Sensitivity Conferred by ligA Alleles from Psychrophilic Bacteria upon Substitution in Mesophilic Bacteria and a Yeast Species

    PubMed Central

    Pankowski, Jarosław A.; Puckett, Stephanie M.

    2016-01-01

    We have assembled a collection of 13 psychrophilic ligA alleles that can serve as genetic elements for engineering mesophiles to a temperature-sensitive (TS) phenotype. When these ligA alleles were substituted into Francisella novicida, they conferred a TS phenotype with restrictive temperatures between 33 and 39°C. When the F. novicida ligA hybrid strains were plated above their restrictive temperatures, eight of them generated temperature-resistant variants. For two alleles, the mutations that led to temperature resistance clustered near the 5′ end of the gene, and the mutations increased the predicted strength of the ribosome binding site at least 3-fold. Four F. novicida ligA hybrid strains generated no temperature-resistant variants at a detectable level. These results suggest that multiple mutations are needed to create temperature-resistant variants of these ligA gene products. One ligA allele was isolated from a Colwellia species that has a maximal growth temperature of 12°C, and this allele supported growth of F. novicida only as a hybrid between the psychrophilic and the F. novicida ligA genes. However, the full psychrophilic gene alone supported the growth of Salmonella enterica, imparting a restrictive temperature of 27°C. We also tested two ligA alleles from two Pseudoalteromonas strains for their ability to support the viability of a Saccharomyces cerevisiae strain that lacked its essential gene, CDC9, encoding an ATP-dependent DNA ligase. In both cases, the psychrophilic bacterial alleles supported yeast viability and their expression generated TS phenotypes. This collection of ligA alleles should be useful in engineering bacteria, and possibly eukaryotic microbes, to predictable TS phenotypes. PMID:26773080

  11. Temperature Sensitivity Conferred by ligA Alleles from Psychrophilic Bacteria upon Substitution in Mesophilic Bacteria and a Yeast Species.

    PubMed

    Pankowski, Jarosław A; Puckett, Stephanie M; Nano, Francis E

    2016-01-01

    We have assembled a collection of 13 psychrophilic ligA alleles that can serve as genetic elements for engineering mesophiles to a temperature-sensitive (TS) phenotype. When these ligA alleles were substituted into Francisella novicida, they conferred a TS phenotype with restrictive temperatures between 33 and 39°C. When the F. novicida ligA hybrid strains were plated above their restrictive temperatures, eight of them generated temperature-resistant variants. For two alleles, the mutations that led to temperature resistance clustered near the 5' end of the gene, and the mutations increased the predicted strength of the ribosome binding site at least 3-fold. Four F. novicida ligA hybrid strains generated no temperature-resistant variants at a detectable level. These results suggest that multiple mutations are needed to create temperature-resistant variants of these ligA gene products. One ligA allele was isolated from a Colwellia species that has a maximal growth temperature of 12°C, and this allele supported growth of F. novicida only as a hybrid between the psychrophilic and the F. novicida ligA genes. However, the full psychrophilic gene alone supported the growth of Salmonella enterica, imparting a restrictive temperature of 27°C. We also tested two ligA alleles from two Pseudoalteromonas strains for their ability to support the viability of a Saccharomyces cerevisiae strain that lacked its essential gene, CDC9, encoding an ATP-dependent DNA ligase. In both cases, the psychrophilic bacterial alleles supported yeast viability and their expression generated TS phenotypes. This collection of ligA alleles should be useful in engineering bacteria, and possibly eukaryotic microbes, to predictable TS phenotypes. PMID:26773080

  12. Methods and materials for the production of L-lactic acid in yeast

    SciTech Connect

    Hause, Ben; Rajgarhia, Vineet; Suominen, Pirkko

    2009-05-19

    Recombinant yeast are provided having, in one aspect, multiple exogenous LDH genes integrated into the genome, while leaving native PDC genes intact. In a second aspect, recombinant yeast are provided having an exogenous LDH gene integrated into its genome at the locus of a native PDC gene, with deletion of the native PDC gene. The recombinant yeast are useful in fermentation process for producing lactic acid.

  13. Expressions of recombinant venom allergen, antigen 5 of yellowjacket (Vespula vulgaris) and paper wasp (Polistes annularis), in bacteria or yeast.

    PubMed

    Monsalve, R I; Lu, G; King, T P

    1999-08-01

    Antigen 5 is a major allergen of vespid venom. It has partial sequence identity with proteins from diverse sources. The biologic function of Ag 5 and its related proteins is not known. We are interested in the expression of Ag 5 with the native conformation of the natural protein since its B cell epitopes are mainly of the discontinuous type. When expressed in bacteria, recombinant Ag 5 formed an insoluble intracellular product, and it did not translocate from cytoplasm to periplasm by the addition of a pelB leader sequence to the cloned protein. When expressed in yeast Pichia pastoris, Ag 5 was secreted because the cloned protein contained a yeast alpha signal leader sequence. Recombinant Ag 5 from yeast was shown to have the native structure of the natural protein and the recombinant Ag 5 from bacteria did not. This was shown by comparison of their solubility, electrophoretic behavior, disulfide bond content, CD spectrum, and binding of IgE antibodies from allergic patients and IgG antibodies from mice immunized with natural Ag 5 or recombinant Ag 5s from yeast or bacteria. These studies were made with Ag 5s from yellowjacket (Vespula vulgaris) and paper wasp (Polistes annularis). PMID:10425162

  14. The Key to Acetate: Metabolic Fluxes of Acetic Acid Bacteria under Cocoa Pulp Fermentation-Simulating Conditions

    PubMed Central

    Adler, Philipp; Frey, Lasse Jannis; Berger, Antje; Bolten, Christoph Josef; Hansen, Carl Erik

    2014-01-01

    Acetic acid bacteria (AAB) play an important role during cocoa fermentation, as their main product, acetate, is a major driver for the development of the desired cocoa flavors. Here, we investigated the specialized metabolism of these bacteria under cocoa pulp fermentation-simulating conditions. A carefully designed combination of parallel 13C isotope labeling experiments allowed the elucidation of intracellular fluxes in the complex environment of cocoa pulp, when lactate and ethanol were included as primary substrates among undefined ingredients. We demonstrate that AAB exhibit a functionally separated metabolism during coconsumption of two-carbon and three-carbon substrates. Acetate is almost exclusively derived from ethanol, while lactate serves for the formation of acetoin and biomass building blocks. Although this is suboptimal for cellular energetics, this allows maximized growth and conversion rates. The functional separation results from a lack of phosphoenolpyruvate carboxykinase and malic enzymes, typically present in bacteria to interconnect metabolism. In fact, gluconeogenesis is driven by pyruvate phosphate dikinase. Consequently, a balanced ratio of lactate and ethanol is important for the optimum performance of AAB. As lactate and ethanol are individually supplied by lactic acid bacteria and yeasts during the initial phase of cocoa fermentation, respectively, this underlines the importance of a well-balanced microbial consortium for a successful fermentation process. Indeed, AAB performed the best and produced the largest amounts of acetate in mixed culture experiments when lactic acid bacteria and yeasts were both present. PMID:24837393

  15. Sialic acid acquisition in bacteria-one substrate, many transporters.

    PubMed

    Thomas, Gavin H

    2016-06-15

    The sialic acids are a family of 9-carbon sugar acids found predominantly on the cell-surface glycans of humans and other animals within the Deuterostomes and are also used in the biology of a wide range of bacteria that often live in association with these animals. For many bacteria sialic acids are simply a convenient source of food, whereas for some pathogens they are also used in immune evasion strategies. Many bacteria that use sialic acids derive them from the environment and so are dependent on sialic acid uptake. In this mini-review I will describe the discovery and characterization of bacterial sialic acids transporters, revealing that they have evolved multiple times across multiple diverse families of transporters, including the ATP-binding cassette (ABC), tripartite ATP-independent periplasmic (TRAP), major facilitator superfamily (MFS) and sodium solute symporter (SSS) transporter families. In addition there is evidence for protein-mediated transport of sialic acids across the outer membrane of Gram negative bacteria, which can be coupled to periplasmic processing of different sialic acids to the most common form, β-D-N-acetylneuraminic acid (Neu5Ac) that is most frequently taken up into the cell. PMID:27284039

  16. Influencing fatty acid composition of yeasts by lanthanides.

    PubMed

    Kolouchova, Irena; Sigler, Karel; Zimola, Michal; Rezanka, Tomas; Matatkova, Olga; Masak, Jan

    2016-08-01

    The growth of microorganisms is affected by cultivation conditions, concentration of carbon and nitrogen sources and the presence of trace elements. One of the new possibilities of influencing the production of cell mass or lipids is the use of lanthanides. Lanthanides are biologically non-essential elements with wide applications in technology and industry and their concentration as environmental contaminants is therefore increasing. Although non-essential, lanthanides have been proposed (and even used) to produce beneficial effects in plants but their mechanisms of action are unclear. Recently, it was suggested that they may replace essential elements or operate as potent blockers of Ca(2+) channels. We tested the effect of low concentrations of lanthanides on traditional biotechnologically useful yeast species (Kluyveromyces polysporus, Saccharomyces cerevisiae, Torulospora delbrueckii), and species capable of high accumulation of lipids (Rhodotorula glutinis, Trichosporon cutaneum, Candida sp., Yarrowia lipolytica). Low concentrations of lanthanum and monazite were conducive to an increase in cell mass and lipids and also higher production of palmitoleic acid, commonly used in cosmetics and medicine, and ω6-linoleic acid which is a precursor of thromboxanes, prostaglandins and leucotrienes. PMID:27339307

  17. Effects of humic acids on the growth of bacteria

    NASA Astrophysics Data System (ADS)

    Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

    2010-03-01

    The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

  18. Biotechnological and in situ food production of polyols by lactic acid bacteria.

    PubMed

    Ortiz, Maria Eugenia; Bleckwedel, Juliana; Raya, Raúl R; Mozzi, Fernanda

    2013-06-01

    Polyols such as mannitol, erythritol, sorbitol, and xylitol are naturally found in fruits and vegetables and are produced by certain bacteria, fungi, yeasts, and algae. These sugar alcohols are widely used in food and pharmaceutical industries and in medicine because of their interesting physicochemical properties. In the food industry, polyols are employed as natural sweeteners applicable in light and diabetic food products. In the last decade, biotechnological production of polyols by lactic acid bacteria (LAB) has been investigated as an alternative to their current industrial production. While heterofermentative LAB may naturally produce mannitol and erythritol under certain culture conditions, sorbitol and xylitol have been only synthesized through metabolic engineering processes. This review deals with the spontaneous formation of mannitol and erythritol in fermented foods and their biotechnological production by heterofermentative LAB and briefly presented the metabolic engineering processes applied for polyol formation. PMID:23604535

  19. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    ERIC Educational Resources Information Center

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

  20. Contribution of Fermentation Yeast to Final Amino Acid Profile in DDGS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One major factor affecting DDGS quality and market values is amino acid (AA) composition. DDGS proteins come from corn and yeast. Yet, the effect of fermentation yeast on DDGS protein quantity and quality (AA profile) has not been well documented. Based on literature review, there are at least 4 met...

  1. Lactic acid bacterium and yeast microbiotas of sixteen French traditional sourdoughs.

    PubMed

    Lhomme, Emilie; Lattanzi, Anna; Dousset, Xavier; Minervini, Fabio; De Angelis, Maria; Lacaze, Guylaine; Onno, Bernard; Gobbetti, Marco

    2015-12-23

    Sixteen sourdoughs (FS1-FS16) used for the manufacture of traditional French breads were characterized by strongly acid conditions (median value of pH 3.5). The concentration of free amino acids (FAA) was highly variable, due to different proteolytic activity of flour used for back slopping and of dominant microorganisms. Median value of cell density of lactic acid bacteria (LAB) was 9.2 log CFU/g. The ratio between LAB and yeasts ranged from 10,000:1 to 10:1. According to the culture-dependent method and 16S metagenetics, Lactobacillus sanfranciscensis was the dominant species in French sourdoughs. FS5 and FS15, propagated according to protocols including one back slopping step at 14 °C, were the only exceptions. High positive correlations were found between L. sanfranciscensis, temperature of back slopping and FAA. The results of this study highlighted the broad adaptability of L. sanfranciscensis to very acid sourdough. Besides species frequently encountered (e.g., Lactobacillus parabrevis/Lactobacillus hammesii, Lactobacillus plantarum and Leuconostoc mesenteroides), first Lactobacillus xiangfangensis (FS5) and Lactobacillus diolivorans (FS15) were found in sourdough. As determined by RAPD-PCR analyses, the sourdough samples showed a different number of strains, ranging from 5 (FS9, FS11 and FS15) to 12 (FS1 and FS13), meaning a highly variable bacterial diversity. Cluster analysis showed that different sourdoughs, especially when propagated in the same bakery, may harbor similar strains. Except for L. plantarum (FS5) and Ln. mesenteroides (FS3), all the dominant species were detected by both 16S metagenetics and culture-dependent method. Yeast diversity was lower than LAB. Except for FS4 (solely dominated by Kazachstania servazzii), yeast microbiota of French sourdoughs was dominated by Saccharomyces cerevisiae. Strains isolated in this study could be a useful base for developing new basic researches on physiology, metabolism, and intraspecific diversity of L

  2. Functional genomics of lactic acid bacteria: from food to health.

    PubMed

    Douillard, François P; de Vos, Willem M

    2014-08-29

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health. PMID:25186768

  3. Functional genomics of lactic acid bacteria: from food to health

    PubMed Central

    2014-01-01

    Genome analysis using next generation sequencing technologies has revolutionized the characterization of lactic acid bacteria and complete genomes of all major groups are now available. Comparative genomics has provided new insights into the natural and laboratory evolution of lactic acid bacteria and their environmental interactions. Moreover, functional genomics approaches have been used to understand the response of lactic acid bacteria to their environment. The results have been instrumental in understanding the adaptation of lactic acid bacteria in artisanal and industrial food fermentations as well as their interactions with the human host. Collectively, this has led to a detailed analysis of genes involved in colonization, persistence, interaction and signaling towards to the human host and its health. Finally, massive parallel genome re-sequencing has provided new opportunities in applied genomics, specifically in the characterization of novel non-GMO strains that have potential to be used in the food industry. Here, we provide an overview of the state of the art of these functional genomics approaches and their impact in understanding, applying and designing lactic acid bacteria for food and health. PMID:25186768

  4. Remediation of acid mine drainage with sulfate reducing bacteria

    SciTech Connect

    Hauri, J.F.; Schaider, L.A.

    2009-02-15

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

  5. Role of Alcohols in Growth, Lipid Composition, and Membrane Fluidity of Yeasts, Bacteria, and Archaea ▿

    PubMed Central

    Huffer, Sarah; Clark, Melinda E.; Ning, Jonathan C.; Blanch, Harvey W.; Clark, Douglas S.

    2011-01-01

    Increased membrane fluidity, which causes cofactor leakage and loss of membrane potential, has long been documented as a cause for decreased cell growth during exposure to ethanol, butanol, and other alcohols. Reinforcement of the membrane with more complex lipid components is thus thought to be beneficial for the generation of more tolerant organisms. In this study, organisms with more complex membranes, namely, archaea, did not maintain high growth rates upon exposure to alcohols, indicating that more complex lipids do not necessarily fortify the membrane against the fluidizing effects of alcohols. In the presence of alcohols, shifts in lipid composition to more saturated and unbranched lipids were observed in most of the organisms tested, including archaea, yeasts, and bacteria. However, these shifts did not always result in a decrease in membrane fluidity or in greater tolerance of the organism to alcohol exposure. In general, organisms tolerating the highest concentrations of alcohols maintained membrane fluidity after alcohol exposure, whereas organisms that increased membrane rigidity were less tolerant. Altered lipid composition was a common response to alcohol exposure, with the most tolerant organisms maintaining a modestly fluid membrane. Our results demonstrate that increased membrane fluidity is not the sole cause of growth inhibition and that alcohols may also denature proteins within the membrane and cytosol, adversely affecting metabolism and decreasing cell growth. PMID:21784917

  6. Antimicrobial activity of some Pacific Northwest woods against anaerobic bacteria and yeast.

    PubMed

    Johnston, W H; Karchesy, J J; Constantine, G H; Craig, A M

    2001-11-01

    Extracts of woods commonly used for animal bedding were tested for antimicrobial activity. Essential oils from Alaska cedar (Chamaecyparis nootkatensis), western juniper (Juniperus occidentalis) and old growth Douglas fir (Pseudotsuga menziesii) as well as methanol extracts of wood from these trees plus western red cedar (Thuja plicata) and ponderosa pine (Pinus ponderosa) were tested for antimicrobial activity against anaerobic bacteria and yeast. The test microbes included Fusobacterium necrophorum, Clostridium perfringens, Actinomyces bovis and Candida albicans which are common to foot diseases and other infections in animals. The essential oils and methanol extracts were tested using a standardized broth assay. Only extracts of Alaska cedar and western juniper showed significant antimicrobial activity against each of the microbes tested. The essential oil of Douglas fir did show antimicrobial activity against A. bovis at the concentrations tested. The methanol extracts of the heartwood of Douglas fir and the sapwood of ponderosa pine showed no antimicrobial activity. The major chemical components of western juniper (cedrol and alpha- and beta-cedrene) and Alaska cedar (nootkatin) were also tested. In western juniper, alpha- and beta-cedrene were found to be active components. Nootkatin showed activity only against C. albicans. The inhibitory activity in Alaska cedar oil was high enough to justify further efforts to define the other chemical components responsible for the antimicrobial activity. PMID:11746838

  7. Optimum production and characterization of an acid protease from marine yeast Metschnikowia reukaufii W6b

    NASA Astrophysics Data System (ADS)

    Li, Jing; Peng, Ying; Wang, Xianghong; Chi, Zhenming

    2010-12-01

    The marine yeast strain W6b isolated from sediment of the South China Sea was found to produce a cell-bound acid protease. The crude acid protease produced by this marine yeast showed the highest activity at pH 3.5 and 40 °C. The optimal pH and temperature for the crude acid protease were in agreement with those for acid protease produced by the terrestrial yeasts. The optimal medium of the acid protease production was seawater containing 1.0% glucose, 1.5% casein, and 0.5% yeast extract, and the optimal cultivation conditions of the acid protease production were pH 4.0, a temperature of 25 °C and a shaking speed of 140 rmin-1. Under the optimal conditions, 72.5 UmL-1 of acid protease activity could be obtained in cell suspension within 48 h of fermentation at shake flask level. The acid protease production was induced by high-molecular-weight nitrogen sources and repressed by low-molecular-weight nitrogen sources. Skimmed-milk-clotting test showed that the crude acid protease from the cell suspension of the yeast W6b had high skimmed milk coagulability. The acid protease produced by M. reukaufii W6b may have highly potential applications in cheese, food and fermentation industries.

  8. Metabolic engineering of yeast to produce fatty acid-derived biofuels: bottlenecks and solutions.

    PubMed

    Sheng, Jiayuan; Feng, Xueyang

    2015-01-01

    Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles. PMID:26106371

  9. Metabolic engineering of yeast to produce fatty acid-derived biofuels: bottlenecks and solutions

    PubMed Central

    Sheng, Jiayuan; Feng, Xueyang

    2015-01-01

    Fatty acid-derived biofuels can be a better solution than bioethanol to replace petroleum fuel, since they have similar energy content and combustion properties as current transportation fuels. The environmentally friendly microbial fermentation process has been used to synthesize advanced biofuels from renewable feedstock. Due to their robustness as well as the high tolerance to fermentation inhibitors and phage contamination, yeast strains such as Saccharomyces cerevisiae and Yarrowia lipolytica have attracted tremendous attention in recent studies regarding the production of fatty acid-derived biofuels, including fatty acids, fatty acid ethyl esters, fatty alcohols, and fatty alkanes. However, the native yeast strains cannot produce fatty acids and fatty acid-derived biofuels in large quantities. To this end, we have summarized recent publications in this review on metabolic engineering of yeast strains to improve the production of fatty acid-derived biofuels, identified the bottlenecks that limit the productivity of biofuels, and categorized the appropriate approaches to overcome these obstacles. PMID:26106371

  10. Characterization of acetic acid bacteria in "traditional balsamic vinegar".

    PubMed

    Gullo, Maria; Caggia, Cinzia; De Vero, Luciana; Giudici, Paolo

    2006-02-01

    This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with concentrated cooked must. On the contrary, ethanol concentration of the cooked and fermented must is less significant for acetic acid bacteria growth. A tentative identification of the isolated strains was done by 16S-23S-5S rDNA PCR/RFLP technique and the isolated strains were clustered: 32 strains belong to Gluconacetobacter xylinus group, two strains to Acetobacter pasteurianus group and one to Acetobacter aceti. PMID:16214251

  11. Improved ethyl caproate production of Chinese liquor yeast by overexpressing fatty acid synthesis genes with OPI1 deletion.

    PubMed

    Chen, Yefu; Luo, Weiwei; Gong, Rui; Xue, Xingxiang; Guan, Xiangyu; Song, Lulu; Guo, Xuewu; Xiao, Dongguang

    2016-09-01

    During yeast fermentation, ethyl esters play a key role in the development of the flavor profiles of Chinese liquor. Ethyl caproate, an ethyl ester eliciting apple-like flavor, is the characteristic flavor of strong aromatic liquor, which is the best selling liquor in China. In the traditional fermentation process, ethyl caproate is mainly produced at the later fermentation stage by aroma-producing yeast, bacteria, and mold in a mud pit instead of Saccharomyces cerevisiae at the expense of grains and fermentation time. To improve the production of ethyl caproate by Chinese liquor yeast (S. cerevisiae) with less food consumption and shorter fermentation time, we constructed three recombinant strains, namely, α5-ACC1ΔOPI1, α5-FAS1ΔOPI1, and α5-FAS2ΔOPI1 by overexpressing acetyl-CoA carboxylase (ACC1), fatty acid synthase 1 (FAS1), and fatty acid synthase 2 (FAS2) with OPI1 (an inositol/choline-mediated negative regulatory gene) deletion, respectively. In the liquid fermentation of corn hydrolysate, the contents of ethyl caproate produced by α5-ACC1ΔOPI1, α5-FAS1ΔOPI1, and α5-FAS2ΔOPI1 increased by 0.40-, 1.75-, and 0.31-fold, correspondingly, compared with the initial strain α5. The contents of other fatty acid ethyl esters (FAEEs) (C8:0, C10:0, C12:0) also increased. In comparison, the content of FAEEs produced by α5-FAS1ΔOPI1 significantly improved. Meanwhile, the contents of acetyl-CoA and ethyl acetate were enhanced by α5-FAS1ΔOPI1. Overall, this study offers a promising platform for the development of pure yeast culture fermentation of Chinese strong aromatic liquor without the use of a mud pit. PMID:27344573

  12. Decarboxylation of Sorbic Acid by Spoilage Yeasts Is Associated with the PAD1 Gene▿

    PubMed Central

    Stratford, Malcolm; Plumridge, Andrew; Archer, David B.

    2007-01-01

    The spoilage yeast Saccharomyces cerevisiae degraded the food preservative sorbic acid (2,4-hexadienoic acid) to a volatile hydrocarbon, identified by gas chromatography mass spectrometry as 1,3-pentadiene. The gene responsible was identified as PAD1, previously associated with the decarboxylation of the aromatic carboxylic acids cinnamic acid, ferulic acid, and coumaric acid to styrene, 4-vinylguaiacol, and 4-vinylphenol, respectively. The loss of PAD1 resulted in the simultaneous loss of decarboxylation activity against both sorbic and cinnamic acids. Pad1p is therefore an unusual decarboxylase capable of accepting both aromatic and aliphatic carboxylic acids as substrates. All members of the Saccharomyces genus (sensu stricto) were found to decarboxylate both sorbic and cinnamic acids. PAD1 homologues and decarboxylation activity were found also in Candida albicans, Candida dubliniensis, Debaryomyces hansenii, and Pichia anomala. The decarboxylation of sorbic acid was assessed as a possible mechanism of resistance in spoilage yeasts. The decarboxylation of either sorbic or cinnamic acid was not detected for Zygosaccharomyces, Kazachstania (Saccharomyces sensu lato), Zygotorulaspora, or Torulaspora, the genera containing the most notorious spoilage yeasts. Scatter plots showed no correlation between the extent of sorbic acid decarboxylation and resistance to sorbic acid in spoilage yeasts. Inhibitory concentrations of sorbic acid were almost identical for S. cerevisiae wild-type and Δpad1 strains. We concluded that Pad1p-mediated sorbic acid decarboxylation did not constitute a significant mechanism of resistance to weak-acid preservatives by spoilage yeasts, even if the decarboxylation contributed to spoilage through the generation of unpleasant odors. PMID:17766451

  13. Acetic acid bacteria: A group of bacteria with versatile biotechnological applications.

    PubMed

    Saichana, Natsaran; Matsushita, Kazunobu; Adachi, Osao; Frébort, Ivo; Frebortova, Jitka

    2015-11-01

    Acetic acid bacteria are gram-negative obligate aerobic bacteria assigned to the family Acetobacteraceae of Alphaproteobacteria. They are members of the genera Acetobacter, Gluconobacter, Gluconacetobacter, Acidomonas, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia, Granulibacter, Tanticharoenia, Ameyamaea, Neokomagataea, and Komagataeibacter. Many strains of Acetobacter and Komagataeibacter have been known to possess high acetic acid fermentation ability as well as the acetic acid and ethanol resistance, which are considered to be useful features for industrial production of acetic acid and vinegar, the commercial product. On the other hand, Gluconobacter strains have the ability to perform oxidative fermentation of various sugars, sugar alcohols, and sugar acids leading to the formation of several valuable products. Thermotolerant strains of acetic acid bacteria were isolated in order to serve as the new strains of choice for industrial fermentations, in which the cooling costs for maintaining optimum growth and production temperature in the fermentation vessels could be significantly reduced. Genetic modifications by adaptation and genetic engineering were also applied to improve their properties, such as productivity and heat resistance. PMID:25485864

  14. Heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals

    SciTech Connect

    Collins, Y.E.; Stotzky, G. )

    1992-05-01

    The electrokinetic patterns of four bacterial species (Bacillus subtilis, Bacillus megaterium, Pseudomonas aeruginosa, and Agrobacterium radiobacter), two yeasts (Saccharomyces cerevisiae and Candida albicans), and two clay minerals (montmorillonite and kaolinite) in the presence of the chloride salts of the heavy metals, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, and of Na and Mg were determined by microelectrophoresis. The cells and kaolinite were net negatively charged at pH values above their isoelectric points (pI) in the presence of Na, Mg, Hg, and Pb at an ionic strength ([mu]) of 3 [times] 10[sup [minus]4]; montmorillonite has no pI and was net negatively charged at all pH values in the presence of these metals. However, the charge of some bacteria, S. cerevisiae, and kaolinite changed to a net positive charge (charge reversal) in the presence of Cd, Cr, Cu, Ni, and Zn at pH values above 5.0 and then at higher pH values, again became negative. The charge of the bacteria and S. cerevisiae also reversed in solutions of Cu and Ni with a [mu] of >3 [times] 10[sup [minus]4], whereas there was no reversal in solutions with a [mu] of <3 [times] 10[sup [minus]4]. The clays became net positively charged when the [mu] of Cu was >3 [times] 10[sup [minus]4] and that of Ni was >1.5 [times] 10[sup [minus]4]. The charge of the cells and clays also reversed in solutions containing both Mg and Ni or both Cu and Ni (except montmorillonite) but not in solutions containing both Mg and Cu (except kaolinite). The pIs of the cells in the presence of the heavy metals were at either higher or lower pH values than in the presence of Na and Mg. Exposure of the cells to the various metals at pH values from 2 to 9 for the short times (ca. 10 min) required to measured the electrophoretic mobility did not affect their viability.

  15. 16 years research on lactic acid production with yeast - ready for the market?

    PubMed

    Sauer, Michael; Porro, Danilo; Mattanovich, Diethard; Branduardi, Paola

    2010-01-01

    The use of plastic produced from non-renewable resources constitutes a major environmental problem of the modern society. Polylactide polymers (PLA) have recently gained enormous attention as one possible substitution of petroleum derived polymers. A prerequisite for high quality PLA production is the provision of optically pure lactic acid, which cannot be obtained by chemical synthesis in an economical way. Microbial fermentation is therefore the commercial option to obtain lactic acid as monomer for PLA production. However, one major economic hurdle for commercial lactic acid production as basis for PLA is the costly separation procedure, which is needed to recover and purify the product from the fermentation broth. Yeasts, such as Saccharomyces cerevisiae (bakers yeast) offer themselves as production organisms because they can tolerate low pH and grow on mineral media what eases the purification of the acid. However, naturally yeasts do not produce lactic acid. By metabolic engineering, ethanol was exchanged with lactic acid as end product of fermentation. A vast amount of effort has been invested into the development of yeasts for lactic acid production since the first paper on this topic by Dequin and Barre appeared 1994. Now yeasts are very close to industrial exploitation - here we summarize the developments in this field. PMID:21415900

  16. Soil Bacteria Take Up D-Amino Acids, Protect Plants

    NASA Astrophysics Data System (ADS)

    Sun, H. J.; Zhang, G.

    2011-12-01

    Recently, many groups reported D-amino acid uptake by plant roots, raising the question of whether soil D-amino acids represent a source of nitrogen or a source of toxicity. The discussion needs to be placed in the context of competition with rhizosphere bacteria. To provide this context, we followed the concentrations of D- and L-enantiomers of alanine, glutamic acid, aspartic acid, and leucine after they were added to soils in the laboratory. In all cases, the uptake of L-enantiomer began immediately and proceeded rapidly until exhausted. In contrast, the uptake of D-enantiomer required induction: an initial period of inactivity followed by rapid consumption comparable in rate to L-enantiomer. The induced nature of the D activity was confirmed by the addition of rifampicin, an mRNA synthesis inhibitor. Preventing the synthesis of new enzymes abolished soil flora's ability to consume D-amino acids, but not L-amino acids. These results suggest that inducible special racemase enzymes, which can convert D-amino acids back to their native L-forms, are widespread among soil microorganisms. This finding does not rule out the possibility that some plants may out-compete microorganisms and be able to access D-amino acids. It does suggest, however, that rhizosphere bacteria can shield plants from the toxic effect of D-amino acids.

  17. Systems solutions by lactic acid bacteria: from paradigms to practice

    PubMed Central

    2011-01-01

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  18. Systems solutions by lactic acid bacteria: from paradigms to practice.

    PubMed

    de Vos, Willem M

    2011-08-30

    Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. PMID:21995776

  19. Effects of lactic acid bacteria contamination on lignocellulosic ethanol fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Slower fermentation rates, mixed sugar compositions, and lower sugar concentrations may make lignocellulosic fermentations more susceptible to contamination by lactic acid bacteria (LAB), which is a common and costly problem to the corn-based fuel ethanol industry. To examine the effects of LAB con...

  20. PRODUCTION OF MANNITOL BY LACTIC ACID BACTERIA: A REVIEW

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mannitol, a naturally occurring polyol, can be produced by lactic acid bacteria (LAB) by fermentation. Some homofermentative LAB produce small amounts of mannitol from glucose. Several heterofermentative LAB can produce mannitol effectively from fructose. In this article, a review on mannitol pro...

  1. Make use of lactic acid bacteria in biomass to biofuel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) have been widely used in dairy fermentations, nutraceuticals, and probiotic/prebiotic applications. Selected strains from the LAB could potentially be used as microbial catalysts for production of fuels and chemicals from lignocellulosic biomass. The unique traits of lac...

  2. Phenotypic and genotypic diversity of wine yeasts used for acidic musts.

    PubMed

    Kunicka-Styczyńska, Alina; Rajkowska, Katarzyna

    2012-05-01

    The aim of this study was to examine the physiological and genetic stability of the industrial wine yeasts Saccharomyces cerevisiae and Saccharomyces bayanus var. uvarum under acidic stress during fermentation. The yeasts were sub-cultured in aerobic or fermentative conditions in media with or without l-malic acid. Changes in the biochemical profiles, karyotypes, and mitochondrial DNA profiles were assessed after minimum 50 generations. All yeast segregates showed a tendency to increase the range of compounds used as sole carbon sources. The wild strains and their segregates were aneuploidal or diploidal. One of the four strains of S. cerevisiae did not reveal any changes in the electrophoretic profiles of chromosomal and mitochondrial DNA, irrespective of culture conditions. The extent of genomic changes in the other yeasts was strain-dependent. In the karyotypes of the segregates, the loss of up to 2 and the appearance up to 3 bands was noted. The changes in their mtDNA patterns were much broader, reaching 5 missing and 10 additional bands. The only exception was S. bayanus var. uvarum Y.00779, characterized by significantly greater genome plasticity only under fermentative stress. Changes in karyotypes and mtDNA profiles prove that fermentative stress is the main driving force of the adaptive evolution of the yeasts. l-malic acid does not influence the extent of genomic changes and the resistance of wine yeasts exhibiting increased demalication activity to acidic stress is rather related to their ability to decompose this acid. The phenotypic changes in segregates, which were found even in yeasts that did not reveal deviations in their DNA profiles, show that phenotypic characterization may be misleading in wine yeast identification. Because of yeast gross genomic diversity, karyotyping even though it does not seem to be a good discriminative tool, can be useful in determining the stability of wine yeasts. Restriction analysis of mitochondrial DNA appears to be

  3. Identifying and assessing the impact of wine acid-related genes in yeast.

    PubMed

    Chidi, Boredi S; Rossouw, Debra; Bauer, Florian F

    2016-02-01

    Saccharomyces cerevisiae strains used for winemaking show a wide range of fermentation phenotypes, and the genetic background of individual strains contributes significantly to the organoleptic properties of wine. This strain-dependent impact extends to the organic acid composition of the wine, an important quality parameter. However, little is known about the genes which may impact on organic acids during grape must fermentation. To generate novel insights into the genetic regulation of this metabolic network, a subset of genes was identified based on a comparative analysis of the transcriptomes and organic acid profiles of different yeast strains showing different production levels of organic acids. These genes showed significant inter-strain differences in their transcription levels at one or more stages of fermentation and were also considered likely to influence organic acid metabolism based on existing functional annotations. Genes selected in this manner were ADH3, AAD6, SER33, ICL1, GLY1, SFC1, SER1, KGD1, AGX1, OSM1 and GPD2. Yeast strains carrying deletions for these genes were used to conduct fermentations and determine organic acid levels at various stages of alcoholic fermentation in synthetic grape must. The impact of these deletions on organic acid profiles was quantified, leading to novel insights and hypothesis generation regarding the role/s of these genes in wine yeast acid metabolism under fermentative conditions. Overall, the data contribute to our understanding of the roles of selected genes in yeast metabolism in general and of organic acid metabolism in particular. PMID:26040556

  4. Lactic acid bacteria isolated from soy sauce mash in Thailand.

    PubMed

    Tanasupawat, Somboon; Thongsanit, Jaruwan; Okada, Sanae; Komagata, Kazuo

    2002-08-01

    Fourteen sphere-shaped and 30 rod-shaped lactic acid bacteria were isolated from soy sauce mash of two factories in Thailand. These strains were separated into two groups, Group A and Group B, by cell shape and DNA-DNA similarity. Group A contained 14 tetrad-forming strains, and these strains were identified as Tetragenococcus halophilus by DNA similarity. Group B contained 30 rod-shaped bacteria, and they were further divided into four Subgroups, B1, B2, B3, and B4, and three ungrouped strains by phenotypic characteristics and DNA similarity. Subgroup B1 contained 16 strains, and these strains were identified as Lactobacillus acidipiscis by DNA similarity. Subgroup B2 included two strains, and the strains were identified as Lactobacillus farciminis by DNA similarity. Subgroup B3 contained five strains. The strains had meso-diaminopimelic acid in the cell wall, and were identified as Lactobacillus pentosus by DNA similarity. The strains tested produced DL-lactic acid from D-glucose. Subgroup B4 contained four strains. The strains had meso-diaminopimelic acid in the cell wall, and they were identified as Lactobacillus plantarum by DNA similarity. Two ungrouped strains were homofermentative, and one was heterofermentative. They showed a low degree of DNA similarity with the type strains tested, and were left unnamed. The distribution of lactic acid bacteria in soy sauce mash in Thailand is discussed. PMID:12469319

  5. Lactic Acid Bacteria – Friend or Foe? Lactic Acid Bacteria in the Production of Polysaccharides and Fuel Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating a-(1,6) and a-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, we have developed improved...

  6. Antibiotic resistance in food lactic acid bacteria--a review.

    PubMed

    Mathur, Shalini; Singh, Rameshwar

    2005-12-15

    Antibiotics are a major tool utilized by the health care industry to fight bacterial infections; however, bacteria are highly adaptable creatures and are capable of developing resistance to antibiotics. Consequently, decades of antibiotic use, or rather misuse, have resulted in bacterial resistance to many modern antibiotics. This antibiotic resistance can cause significant danger and suffering for many people with common bacterial infections, those once easily treated with antibiotics. For several decades studies on selection and dissemination of antibiotic resistance have focused mainly on clinically relevant species. However, recently many investigators have speculated that commensal bacteria including lactic acid bacteria (LAB) may act as reservoirs of antibiotic resistance genes similar to those found in human pathogens. The main threat associated with these bacteria is that they can transfer resistance genes to pathogenic bacteria. Genes conferring resistance to tetracycline, erythromycin and vancomycin have been detected and characterized in Lactococcus lactis, Enterococci and, recently, in Lactobacillus species isolated from fermented meat and milk products. A number of initiatives have been recently launched by various organizations across the globe to address the biosafety concerns of starter cultures and probiotic microorganisms. The studies can lead to better understanding of the role played by the dairy starter microorganisms in horizontal transfer of antibiotic resistance genes to intestinal microorganisms and food-associated pathogenic bacteria. PMID:16289406

  7. Lipid production on free fatty acids by oleaginous yeasts under non-growth conditions.

    PubMed

    Yang, Xiaobing; Jin, Guojie; Wang, Yandan; Shen, Hongwei; Zhao, Zongbao K

    2015-10-01

    Microbial lipids produced by oleaginous yeasts serve as promising alternatives to traditional oils and fats for the production of biodiesel and oleochemicals. To improve its techno-economics, it is pivotal to use wastes and produce high quality lipids of special fatty acid composition. In the present study, four oleaginous yeasts were tested to use free fatty acids for lipid production under non-growth conditions. Microbial lipids of exceptionally high fatty acid relative contents, e.g. those contained over 70% myristic acid or 80% oleic acid, were produced that may be otherwise inaccessible by growing cells on various carbon sources. It was found that Cryptococcus curvatus is a robust strain that can efficiently use oleic acid as well as even-numbered saturated fatty acids with carbon atoms ranging from 10 to 20. Our results provided new opportunity for the production of functional lipids and for the exploitation of organic wastes rich in free fatty acids. PMID:26159379

  8. Lactic acid bacteria as a cell factory for riboflavin production

    PubMed Central

    Thakur, Kiran; De, Sachinandan

    2015-01-01

    Summary Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin‐enriched functional foods, proper selection and exploitation of riboflavin‐producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. PMID:26686515

  9. Amino acid-containing membrane lipids in bacteria.

    PubMed

    Geiger, Otto; González-Silva, Napoleón; López-Lara, Isabel M; Sohlenkamp, Christian

    2010-01-01

    In the bacterial model organism Escherichia coli only the three major membrane lipids phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin occur, all of which belong to the glycerophospholipids. The amino acid-containing phosphatidylserine is a major lipid in eukaryotic membranes but in most bacteria it occurs only as a minor biosynthetic intermediate. In some bacteria, the anionic glycerophospholipids phosphatidylglycerol and cardiolipin can be decorated with aminoacyl residues. For example, phosphatidylglycerol can be decorated with lysine, alanine, or arginine whereas in the case of cardiolipin, lysine or d-alanine modifications are known. In few bacteria, diacylglycerol-derived lipids can be substituted with lysine or homoserine. Acyl-oxyacyl lipids in which the lipidic part is amide-linked to the alpha-amino group of an amino acid are widely distributed among bacteria and ornithine-containing lipids are the most common version of this lipid type. Only few bacterial groups form glycine-containing lipids, serineglycine-containing lipids, sphingolipids, or sulfonolipids. Although many of these amino acid-containing bacterial membrane lipids are produced in response to certain stress conditions, little is known about the specific molecular functions of these lipids. PMID:19703488

  10. Lactic acid bacteria as a cell factory for riboflavin production.

    PubMed

    Thakur, Kiran; Tomar, Sudhir Kumar; De, Sachinandan

    2016-07-01

    Consumers are increasingly becoming aware of their health and nutritional requirements, and in this context, vitamins produced in situ by microbes may suit their needs and expectations. B groups vitamins are essential components of cellular metabolism and among them riboflavin is one of the vital vitamins required by bacteria, plants, animals and humans. Here, we focus on the importance of microbial production of riboflavin over chemical synthesis. In addition, genetic abilities for riboflavin biosynthesis by lactic acid bacteria are discussed. Genetically modified strains by employing genetic engineering and chemical analogues have been developed to enhance riboflavin production. The present review attempts to collect the currently available information on riboflavin production by microbes in general, while placing greater emphasis on food grade lactic acid bacteria and human gut commensals. For designing riboflavin-enriched functional foods, proper selection and exploitation of riboflavin-producing lactic acid bacteria is essential. Moreover, eliminating the in situ vitamin fortification step will decrease the cost of food production. PMID:26686515

  11. The effect of linoleic acid on the Sauvignon blanc fermentation by different wine yeast strains.

    PubMed

    Casu, Francesca; Pinu, Farhana R; Fedrizzi, Bruno; Greenwood, David R; Villas-Boas, Silas G

    2016-08-01

    The level of linoleic acid in the Sauvignon blanc (SB) grape juice affects the development of different aroma compounds during fermentation by Saccharomyces cerevisiae EC1118, including key varietal thiols such as 3-mercaptohexanol (3MH) and 3-mercaptohexyl acetate (3MHA). However, it is still unknown if linoleic acid would affect in a similar way other commonly used S. cerevisiae wine strains. Here we investigated the effect of grape juice linoleic acid on the development of aroma compounds and other metabolites of SB wines using different wine yeast strains: EC1118, AWRI796 and VIN13. Linoleic acid clearly affected the levels of acetylated aroma compounds, several amino acids, and antioxidant molecules, independent of yeast strain, but the production of 3MH was affected by linoleic acid in a strain-specific manner. Moreover, the supplementation of deuterium-labelled 3MH also affected the production of varietal thiols in a strain-specific way. Linoleic acid reduced the acetylation process probably by inhibiting an acetyltransferase, an effect that was independent of the yeast strain. However, regulation of the 3MH biosynthesis is strain-specific, which suggests a mindful consideration not only towards the wine yeast but also to the linoleic acid concentration in the grape juice in order to obtain the desired wine aroma characteristics. PMID:27364827

  12. Biotransformation of volatile fatty acids by oleaginous and non-oleaginous yeast species.

    PubMed

    Kolouchová, Irena; Schreiberová, Olga; Sigler, Karel; Masák, Jan; Řezanka, Tomáš

    2015-11-01

    The possibility of utilizing volatile fatty acids (VFA)-containing waste substrates from biotechnological and industrial processes was investigated by cultivating both oleaginous (Candida sp., Rhodotorula glutinis, Trichosporon cutaneum, Yarrowia lipolytica) and non-oleaginous (Kluyveromyces polysporus, Saccharomyces cerevisiae, Torulaspora delbrueckii) yeast species on acetic acid, propionic acid and a combination of either acid with glucose as carbon and energy sources. Both oleaginous and non-oleaginous yeasts grew on VFA. Oleaginous yeasts accumulated lipids to 15-48% of dry cell weight, non-oleaginous yeasts also grew on VFA and showed comparable biomass yields but the lipid content was only 2-5%. Biomass and lipid yield increased in cultivations on VFA plus glucose. The lipid composition was comparable to plant-derived oils and therefore might be exploitable in biodiesel production; nearly all species, when cultured on propionate, showed a high content of the desirable odd-chain unsaturated FA, especially 17:1 acid. This study points at the wide array of possible applications of many yeasts, even non-oleaginous strains, for biovalorization of industrial wastes. Despite their low lipid content these species are useful because they can readily utilize VFA from waste products and, since they are not biologically hazardous, their biomass can be afterwards used, e.g. as livestock fodder. PMID:26323601

  13. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation

    PubMed Central

    Sawada, Kazutaka

    2016-01-01

    Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked lipids in sake fermentation mash is derived from the sake yeast rather than from rice or koji (rice fermented with Aspergillus). Additionally, during alcoholic fermentation, inhibition of the residual mitochondrial activity of sake yeast increases the levels of unsaturated fatty acids of ester-linked lipids. These findings indicate that the residual activity of the mitochondrial electron transport chain reduces molecular oxygen levels and decreases the synthesis of unsaturated fatty acids, thereby increasing the synthesis of estery flavors by sake yeast. This is the first report of a novel link between residual mitochondrial transmembrane potential and the synthesis of unsaturated fatty acids by the brewery yeast during alcoholic fermentation. PMID:26839744

  14. Residual mitochondrial transmembrane potential decreases unsaturated fatty acid level in sake yeast during alcoholic fermentation.

    PubMed

    Sawada, Kazutaka; Kitagaki, Hiroshi

    2016-01-01

    Oxygen, a key nutrient in alcoholic fermentation, is rapidly depleted during this process. Several pathways of oxygen utilization have been reported in the yeast Saccharomyces cerevisiae during alcoholic fermentation, namely synthesis of unsaturated fatty acid, sterols and heme, and the mitochondrial electron transport chain. However, the interaction between these pathways has not been investigated. In this study, we showed that the major proportion of unsaturated fatty acids of ester-linked lipids in sake fermentation mash is derived from the sake yeast rather than from rice or koji (rice fermented with Aspergillus). Additionally, during alcoholic fermentation, inhibition of the residual mitochondrial activity of sake yeast increases the levels of unsaturated fatty acids of ester-linked lipids. These findings indicate that the residual activity of the mitochondrial electron transport chain reduces molecular oxygen levels and decreases the synthesis of unsaturated fatty acids, thereby increasing the synthesis of estery flavors by sake yeast. This is the first report of a novel link between residual mitochondrial transmembrane potential and the synthesis of unsaturated fatty acids by the brewery yeast during alcoholic fermentation. PMID:26839744

  15. A Glutamic Acid-Producing Lactic Acid Bacteria Isolated from Malaysian Fermented Foods

    PubMed Central

    Zareian, Mohsen; Ebrahimpour, Afshin; Bakar, Fatimah Abu; Mohamed, Abdul Karim Sabo; Forghani, Bita; Ab-Kadir, Mohd Safuan B.; Saari, Nazamid

    2012-01-01

    l-glutamaic acid is the principal excitatory neurotransmitter in the brain and an important intermediate in metabolism. In the present study, lactic acid bacteria (218) were isolated from six different fermented foods as potent sources of glutamic acid producers. The presumptive bacteria were tested for their ability to synthesize glutamic acid. Out of the 35 strains showing this capability, strain MNZ was determined as the highest glutamic-acid producer. Identification tests including 16S rRNA gene sequencing and sugar assimilation ability identified the strain MNZ as Lactobacillus plantarum. The characteristics of this microorganism related to its glutamic acid-producing ability, growth rate, glucose consumption and pH profile were studied. Results revealed that glutamic acid was formed inside the cell and excreted into the extracellular medium. Glutamic acid production was found to be growth-associated and glucose significantly enhanced glutamic acid production (1.032 mmol/L) compared to other carbon sources. A concentration of 0.7% ammonium nitrate as a nitrogen source effectively enhanced glutamic acid production. To the best of our knowledge this is the first report of glutamic acid production by lactic acid bacteria. The results of this study can be further applied for developing functional foods enriched in glutamic acid and subsequently γ-amino butyric acid (GABA) as a bioactive compound. PMID:22754309

  16. Yeast display evolution of a kinetically efficient 13-amino acid substrate for lipoic acid ligase

    PubMed Central

    Puthenveetil, Sujiet; Liu, Daniel S.; White, Katharine A.; Thompson, Samuel; Ting, Alice Y.

    2009-01-01

    E. coli lipoic acid ligase (LplA) catalyzes ATP-dependent covalent ligation of lipoic acid onto specific lysine sidechains of three acceptor proteins involved in oxidative metabolism. Our lab has shown that LplA and engineered mutants can ligate useful small-molecule probes such as alkyl azides (Nat. Biotechnol. 2007, 25, 1483–1487) and photocrosslinkers (Angew. Chem Int. Ed Engl. 2008, 47, 7018–7021) in place of lipoic acid, facilitating imaging and proteomic studies. Both to further our understanding of lipoic acid metabolism, and to improve LplA’s utility as a biotechnological platform, we have engineered a novel 13-amino acid peptide substrate for LplA. LplA’s natural protein substrates have a conserved β-hairpin structure, a conformation that is difficult to recapitulate in a peptide, and thus we performed in vitro evolution to engineer the LplA peptide substrate, called “LplA Acceptor Peptide” (LAP). A ~107 library of LAP variants was displayed on the surface of yeast cells, labeled by LplA with either lipoic acid or bromoalkanoic acid, and the most efficiently labeled LAP clones were isolated by fluorescence activated cell sorting. Four rounds of evolution followed by additional rational mutagenesis produced a “LAP2” sequence with a kcat/Km of 0.99 μM−1min−1, >70-fold better than our previous rationally-designed 22-amino acid LAP1 sequence (Nat. Biotechnol. 2007, 25, 1483–1487), and only 8-fold worse than the kcat/Km values of natural lipoate and biotin acceptor proteins. The kinetic improvement over LAP1 allowed us to rapidly label cell surface peptide-fused receptors with quantum dots. PMID:19863063

  17. Cell wall structure and function in lactic acid bacteria

    PubMed Central

    2014-01-01

    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts. PMID:25186919

  18. Cell wall structure and function in lactic acid bacteria.

    PubMed

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2014-08-29

    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts. PMID:25186919

  19. Lactobionic and cellobionic acid production profiles of the resting cells of acetic acid bacteria.

    PubMed

    Kiryu, Takaaki; Kiso, Taro; Nakano, Hirofumi; Murakami, Hiromi

    2015-01-01

    Lactobionic acid was produced by acetic acid bacteria to oxidize lactose. Gluconobacter spp. and Gluconacetobacter spp. showed higher lactose-oxidizing activities than Acetobacter spp. Gluconobacter frateurii NBRC3285 produced the highest amount of lactobionic acid per cell, among the strains tested. This bacterium assimilated neither lactose nor lactobionic acid. At high lactose concentration (30%), resting cells of the bacterium showed sufficient oxidizing activity for efficient production of lactobionic acid. These properties may contribute to industrial production of lactobionic acid by the bacterium. The bacterium showed higher oxidizing activity on cellobiose than that on lactose and produced cellobionic acid. PMID:25965080

  20. Intracellular pH of acid-tolerant ruminal bacteria.

    PubMed Central

    Russell, J B

    1991-01-01

    Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells. PMID:1781695

  1. Yeast fermentation of carboxylic acids obtained from pyrolytic aqueous phases for lipid production.

    PubMed

    Lian, Jieni; Garcia-Perez, Manuel; Coates, Ralph; Wu, Hongwei; Chen, Shulin

    2012-08-01

    The presence of very reactive C1-C4 molecules adversely affects the quality bio-oils produced from the pyrolysis of lignocellulosic materials. In this paper a scheme to produce lipids with Cryptococcus curvatus from the carboxylic acids in the pyrolytic aqueous phase collected in fractional condensers is proposed. The capacities of three oleaginous yeasts C. curvatus, Rhodotorula glutinis, Lipomyces starkeyi to ferment acetate, formate, hydroxylacat-aldehyde, phenol and acetol were investigated. While acetate could be a good carbon source for lipid production, formate provides additional energy and contributes to yeast growth and lipid production as auxiliary energy resource. Acetol could slightly support yeast growth, but it inhibits lipid accumulation. Hydroxyacetaldehyde and phenols showed high yeast growth and lipid accumulation inhibition. A pyrolytic aqueous phase with 20 g/L acetate was fermented with C. curvatus, after neutralization and detoxification to produce 6.9 g/L dry biomass and 2.2 g/L lipid. PMID:22705522

  2. Ethanol Production by Selected Intestinal Microorganisms and Lactic Acid Bacteria Growing under Different Nutritional Conditions.

    PubMed

    Elshaghabee, Fouad M F; Bockelmann, Wilhelm; Meske, Diana; de Vrese, Michael; Walte, Hans-Georg; Schrezenmeir, Juergen; Heller, Knut J

    2016-01-01

    To gain some specific insight into the roles microorganisms might play in non-alcoholic fatty liver disease (NAFLD), some intestinal and lactic acid bacteria and one yeast (Anaerostipes caccae, Bacteroides thetaiotaomicron, Bifidobacterium longum, Enterococcus fecalis, Escherichia coli, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus plantarum, Weissella confusa, Saccharomyces cerevisiae) were characterized by high performance liquid chromatography for production of ethanol when grown on different carbohydrates: hexoses (glucose and fructose), pentoses (arabinose and ribose), disaccharides (lactose and lactulose), and inulin. Highest amounts of ethanol were produced by S. cerevisiae, L. fermentum, and W. confusa on glucose and by S. cerevisiae and W. confusa on fructose. Due to mannitol-dehydrogenase expressed in L. fermentum, ethanol production on fructose was significantly (P < 0.05) reduced. Pyruvate and citrate, two potential electron acceptors for regeneration of NAD(+)/NADP(+), drastically reduced ethanol production with acetate produced instead in L. fermentum grown on glucose and W. confusa grown on glucose and fructose, respectively. In fecal slurries prepared from feces of four overweight volunteers, ethanol was found to be produced upon addition of fructose. Addition of A. caccae, L. acidophilus, L. fermentum, as well as citrate and pyruvate, respectively, abolished ethanol production. However, addition of W. confusa resulted in significantly (P < 0.05) increased production of ethanol. These results indicate that microorganisms like W. confusa, a hetero-fermentative, mannitol-dehydrogenase negative lactic acid bacterium, may promote NAFLD through ethanol produced from sugar fermentation, while other intestinal bacteria and homo- and hetero-fermentative but mannitol-dehydrogenase positive lactic acid bacteria may not promote NAFLD. Also, our studies indicate that dietary factors interfering with gastrointestinal microbiota and microbial

  3. Ethanol Production by Selected Intestinal Microorganisms and Lactic Acid Bacteria Growing under Different Nutritional Conditions

    PubMed Central

    Elshaghabee, Fouad M. F.; Bockelmann, Wilhelm; Meske, Diana; de Vrese, Michael; Walte, Hans-Georg; Schrezenmeir, Juergen; Heller, Knut J.

    2016-01-01

    To gain some specific insight into the roles microorganisms might play in non-alcoholic fatty liver disease (NAFLD), some intestinal and lactic acid bacteria and one yeast (Anaerostipes caccae, Bacteroides thetaiotaomicron, Bifidobacterium longum, Enterococcus fecalis, Escherichia coli, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus plantarum, Weissella confusa, Saccharomyces cerevisiae) were characterized by high performance liquid chromatography for production of ethanol when grown on different carbohydrates: hexoses (glucose and fructose), pentoses (arabinose and ribose), disaccharides (lactose and lactulose), and inulin. Highest amounts of ethanol were produced by S. cerevisiae, L. fermentum, and W. confusa on glucose and by S. cerevisiae and W. confusa on fructose. Due to mannitol-dehydrogenase expressed in L. fermentum, ethanol production on fructose was significantly (P < 0.05) reduced. Pyruvate and citrate, two potential electron acceptors for regeneration of NAD+/NADP+, drastically reduced ethanol production with acetate produced instead in L. fermentum grown on glucose and W. confusa grown on glucose and fructose, respectively. In fecal slurries prepared from feces of four overweight volunteers, ethanol was found to be produced upon addition of fructose. Addition of A. caccae, L. acidophilus, L. fermentum, as well as citrate and pyruvate, respectively, abolished ethanol production. However, addition of W. confusa resulted in significantly (P < 0.05) increased production of ethanol. These results indicate that microorganisms like W. confusa, a hetero-fermentative, mannitol-dehydrogenase negative lactic acid bacterium, may promote NAFLD through ethanol produced from sugar fermentation, while other intestinal bacteria and homo- and hetero-fermentative but mannitol-dehydrogenase positive lactic acid bacteria may not promote NAFLD. Also, our studies indicate that dietary factors interfering with gastrointestinal microbiota and microbial

  4. Identification of novel secreted fatty acids that regulate nitrogen catabolite repression in fission yeast

    PubMed Central

    Sun, Xiaoying; Hirai, Go; Ueki, Masashi; Hirota, Hiroshi; Wang, Qianqian; Hongo, Yayoi; Nakamura, Takemichi; Hitora, Yuki; Takahashi, Hidekazu; Sodeoka, Mikiko; Osada, Hiroyuki; Hamamoto, Makiko; Yoshida, Minoru; Yashiroda, Yoko

    2016-01-01

    Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence of high-quality nitrogen sources such as NH4+ and glutamate (Glu), which is called nitrogen catabolite repression. Amino acid auxotrophic mutants of the fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing NH4Cl or Glu even when adequate amounts of required amino acids were supplied. However, growth of these mutant cells was recovered in the vicinity of colonies of the prototrophic strain, suggesting that the prototrophic cells secrete some substances that can restore uptake of amino acids by an unknown mechanism. We identified the novel fatty acids, 10(R)-acetoxy-8(Z)-octadecenoic acid and 10(R)-hydroxy-8(Z)-octadecenoic acid, as secreted active substances, referred to as Nitrogen Signaling Factors (NSFs). Synthetic NSFs were also able to shift nitrogen source utilization from high-quality to poor nitrogen sources to allow adaptive growth of the fission yeast amino acid auxotrophic mutants in the presence of high-quality nitrogen sources. Finally, we demonstrated that the Agp3 amino acid transporter was involved in the adaptive growth. The data highlight a novel intra-species communication system for adaptation to environmental nutritional conditions in fission yeast. PMID:26892493

  5. Identification of novel secreted fatty acids that regulate nitrogen catabolite repression in fission yeast.

    PubMed

    Sun, Xiaoying; Hirai, Go; Ueki, Masashi; Hirota, Hiroshi; Wang, Qianqian; Hongo, Yayoi; Nakamura, Takemichi; Hitora, Yuki; Takahashi, Hidekazu; Sodeoka, Mikiko; Osada, Hiroyuki; Hamamoto, Makiko; Yoshida, Minoru; Yashiroda, Yoko

    2016-01-01

    Uptake of poor nitrogen sources such as branched-chain amino acids is repressed in the presence of high-quality nitrogen sources such as NH4(+) and glutamate (Glu), which is called nitrogen catabolite repression. Amino acid auxotrophic mutants of the fission yeast Schizosaccharomyces pombe were unable to grow on minimal medium containing NH4Cl or Glu even when adequate amounts of required amino acids were supplied. However, growth of these mutant cells was recovered in the vicinity of colonies of the prototrophic strain, suggesting that the prototrophic cells secrete some substances that can restore uptake of amino acids by an unknown mechanism. We identified the novel fatty acids, 10(R)-acetoxy-8(Z)-octadecenoic acid and 10(R)-hydroxy-8(Z)-octadecenoic acid, as secreted active substances, referred to as Nitrogen Signaling Factors (NSFs). Synthetic NSFs were also able to shift nitrogen source utilization from high-quality to poor nitrogen sources to allow adaptive growth of the fission yeast amino acid auxotrophic mutants in the presence of high-quality nitrogen sources. Finally, we demonstrated that the Agp3 amino acid transporter was involved in the adaptive growth. The data highlight a novel intra-species communication system for adaptation to environmental nutritional conditions in fission yeast. PMID:26892493

  6. Effect of applying lactic acid bacteria and propionic acid on fermentation quality and aerobic stability of oats-common vetch mixed silage on the Tibetan plateau.

    PubMed

    Zhang, Jie; Guo, Gang; Chen, Lei; Li, Junfeng; Yuan, Xianjun; Yu, Chengqun; Shimojo, Masataka; Shao, Tao

    2015-06-01

    The objective of this study was to evaluate effects of lactic acid bacteria and propionic acid on the fermentation quality and aerobic stability of oats-common vetch mixed silage by using a small-scale fermentation system on the Tibetan plateau. (i) An inoculant (Lactobacillus plantarum) (L) or (ii) propionic acid (P) or (iii) inoculant + propionic acid (PL) were used as additives. After fermenting for 60 days, silos were opened and the aerobic stability was tested for the following 15 days. The results showed that all silages were well preserved with low pH and NH3 -N, and high lactic acid content and V-scores. L and PL silages showed higher (P < 0.05) lactic acid and crude protein content than the control silage. P silage inhibited lactic acid production. Under aerobic conditions, L silage had similar yeast counts as the control silage (> 10(5) cfu/g fresh matter (FM)); however, it numerically reduced aerobic stability for 6 h. P and PL silages showed fewer yeasts (< 10(5) cfu/g FM) (P < 0.05) and markedly improved the aerobic stability (> 360 h). The result suggested that PL is the best additive as it could not only improved fermentation quality, but also aerobic stability of oats-common vetch mixed silage on the Tibetan plateau. PMID:25494579

  7. Lactic acid bacteria from fresh fruit and vegetables as biocontrol agents of phytopathogenic bacteria and fungi.

    PubMed

    Trias, Rosalia; Bañeras, Lluís; Montesinos, Emilio; Badosa, Esther

    2008-12-01

    This study evaluated the efficacy of lactic acid bacteria (LAB) isolated from fresh fruits and vegetables as biocontrol agents against the phytopathogenic and spoilage bacteria and fungi, Xanthomonas campestris, Erwinia carotovora, Penicillium expansum, Monilinia laxa, and Botrytis cinerea. The antagonistic activity of 496 LAB strains was tested in vitro and all tested microorganisms except P. expansum were inhibited by at least one isolate. The 496 isolates were also analyzed for the inhibition of P. expansum infection in wounds of Golden Delicious apples. Four strains (TC97, AC318, TM319, and FF441) reduced the fungal rot diameter of the apples by 20%; only Weissella cibaria strain TM128 decreased infection levels by 50%. Cell-free supernatants of selected antagonistic bacteria were studied to determine the nature of the antimicrobial compounds produced. Organic acids were the preferred mediators of inhibition but hydrogen peroxide was also detected when strains BC48, TM128, PM141 and FF441 were tested against E. carotovora. While previous reports of antifungal activity by LAB are scarce, our results support the potential of LAB as biocontrol agents against postharvest rot. PMID:19204894

  8. Mechanistic modeling of biocorrosion caused by biofilms of sulfate reducing bacteria and acid producing bacteria.

    PubMed

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation. PMID:27071053

  9. Single-Cell Analysis of Growth in Budding Yeast and Bacteria Reveals a Common Size Regulation Strategy.

    PubMed

    Soifer, Ilya; Robert, Lydia; Amir, Ariel

    2016-02-01

    To maintain a constant cell size, dividing cells have to coordinate cell-cycle events with cell growth. This coordination has long been supposed to rely on the existence of size thresholds determining cell-cycle progression [1]. In budding yeast, size is controlled at the G1/S transition [2]. In agreement with this hypothesis, the size at birth influences the time spent in G1: smaller cells have a longer G1 period [3]. Nevertheless, even though cells born smaller have a longer G1, the compensation is imperfect and they still bud at smaller cell sizes. In bacteria, several recent studies have shown that the incremental model of size control, in which size is controlled by addition of a constant volume (in contrast to a size threshold), is able to quantitatively explain the experimental data on four different bacterial species [4-7]. Here, we report on experimental results for the budding yeast Saccharomyces cerevisiae, finding, surprisingly, that cell size control in this organism is very well described by the incremental model, suggesting a common strategy for cell size control with bacteria. Additionally, we argue that for S. cerevisiae the "volume increment" is not added from birth to division, but rather between two budding events. PMID:26776734

  10. Adhesion to silicone rubber of yeasts and bacteria isolated from voice prostheses: influence of salivary conditioning films.

    PubMed

    Busscher, H J; Geertsema-Doornbusch, G I; van der Mei, H C

    1997-02-01

    Adhesion of yeasts and bacteria to silicone rubber is one of the first steps in the biodeterioration of silicone rubber voice prostheses. In this paper, adhesion of two streptococcal, staphylococcal, Candida albicans and Candida tropicalis strains, isolated from explanted voice prostheses was investigated to silicone rubber with and without a salivary conditioning film in a parallel-plate flow chamber. Within each microbial pair of one species, the strain with the most negative zeta potential adhered most slowly to negatively charged silicone rubber. No other clear relationships were obvious between adhesion to silicone rubber and microbial zeta potentials of cell-surface hydrophobicities, as by water contact angles. A 1.5-h adsorbed salivary conditioning film appeared to possess components, presumably albumin and lysozyme, slowing down the deposition of the yeasts and some of the streptococcal and staphylococcal isolates. In addition, microbial adhesion in a stationary end point was generally lower to silicone rubber with an adsorbed salivary conditioning film than without one. Nearly all microorganisms adhering to an adsorbed salivary conditioning film, yeasts as well as bacteria, were stimulated to detach by the passage of an air bubble through the chamber, but microorganisms adhering directly to the silicone rubber, especially C tropicalis strains, detached in far lower numbers under the influence of a passing air bubble. The present observations are in agreement with clinical in vivo findings that in patients with reduced saliva production after radiotherapy, the device life of the voice prosthesis is significantly shortened and suggests that isolated salivary components might be used as an anti-adhesive. PMID:9029300

  11. The concentration of amino acids by yeast cells depleted of adenosine triphosphate

    PubMed Central

    Eddy, A. A.; Backen, K.; Watson, G.

    1970-01-01

    1. The ATP content of preparations of a strain of Saccharomyces carlsbergensis was lowered below 0.3nmol/mg of yeast by starving the yeast cells in the presence of both antimycin and 5mm-deoxyglucose. 2. When the depleted cells were put at pH4.5 with glycine up to about 20nmol of the amino acid/mg of yeast was absorbed without being chemically modified. The mechanism did not depend on an exchange with endogenous amino acids. 3. The concentration of the absorbed glycine could apparently reach 100–200 times that outside the cells. 4. Replacement of the cellular K+ by Na+ almost stopped amino acid absorption in the presence of antimycin and deoxyglucose, but not in their absence. 5. It is suggested that, when energy metabolism itself had stopped, a purely physical process, namely the movements of H+ and K+ into and out of the yeast respectively, served to concentrate the amino acids in the cells. Both ionic species appear to be co-substrates of the system transporting amino acids. PMID:5495157

  12. Main and interaction effects of acetic acid, furfural, and p-hydroxybenzoic acid on growth and ethanol productivity of yeasts

    SciTech Connect

    Palmqvist, E.; Grage, H.; Meinander, N.Q.; Hahn-Haegerdal, B.

    1999-04-05

    The influence of the factors acetic acid, furfural, and p-hydroxybenzoic acid on the ethanol yield (Y{sub EtOH}) of Saccharomyces cerevisiae, bakers` yeast, S. cerevisiae ATCC 96581, and Candida shehatae NJ 23 was investigated using a 2{sup 3}-full factorial design with 3 centerpoints. The results indicated that acetic acid inhibited the fermentation by C. shehatae NJ 23 markedly more than by bakers` yeast, whereas no significant difference in tolerance towards the compounds was detected between the S. cerevisiae strains. Furfural and the lignin derived compound p-hydroxybenzoic acid did not affect any of the yeasts at the cell mass concentration used. The results indicated that the linear model was not adequate to describe the experimental data. Based on the results from the 2{sup 3}-full factorial experiment, an extended experiment was designed based on a central composite design to investigate the influence of the factors on the specific growth rate ({mu}), biomass yield (Y{sub x}), volumetric ethanol productivity (Q{sub EtOH}), and Y{sub EtOH}. Bakers` yeast was chosen in the extended experiment due to its better tolerance towards acetic acid, which makes it a more interesting organism for use in industrial fermentations of lignocellulosic hydrolysates.

  13. Bioconversion of volatile fatty acids into lipids by the oleaginous yeast Yarrowia lipolytica.

    PubMed

    Fontanille, Pierre; Kumar, Vinod; Christophe, Gwendoline; Nouaille, Régis; Larroche, Christian

    2012-06-01

    The valorization of volatile fatty acids into microbial lipids by the oleaginous yeast Yarrowia lipolytica was investigated. Therefore, a two-stage fed-batch strategy was designed: the yeast was initially grown on glucose or glycerol as carbon source, then sequential additions of acetic acid under nitrogen limiting conditions were performed after glucose or glycerol exhaustion. The typical values obtained with an initial 40 g/L concentration of glucose were close to 31 g/L biomass, a lipid concentration of 12.4 g/L, which correspond to a lipid content of the biomass close to 40%. This cultivation strategy was also efficient with other volatile fatty acids (butyric and propionic acids) or with a mixture of these three VFAs. The lipids composition was found quite similar to that of vegetable oils. The study demonstrated the feasibility of simultaneous biovalorization of volatile fatty acids and glycerol, two cheap industrial by-products. PMID:22464419

  14. Biohydrogenation of C20 polyunsaturated fatty acids by anaerobic bacteria.

    PubMed

    Sakurama, Haruko; Kishino, Shigenobu; Mihara, Kousuke; Ando, Akinori; Kita, Keiko; Takahashi, Satomi; Shimizu, Sakayu; Ogawa, Jun

    2014-09-01

    The PUFAs include many bioactive lipids. The microbial metabolism of C18 PUFAs is known to produce their bioactive isomers, such as conjugated FAs and hydroxy FAs, but there is little information on that of C20 PUFAs. In this study, we aimed to obtain anaerobic bacteria with the ability to produce novel PUFAs from C20 PUFAs. Through the screening of ∼100 strains of anaerobic bacteria, Clostridium bifermentans JCM 1386 was selected as a strain with the ability to saturate PUFAs during anaerobic cultivation. This strain converted arachidonic acid (cis-5,cis-8,cis-11,cis-14-eicosatetraenoic acid) and EPA (cis-5,cis-8,cis-11,cis-14,cis-17-EPA) into cis-5,cis-8,trans-13-eicosatrienoic acid and cis-5,cis-8,trans-13,cis-17-eicosatetraenoic acid, giving yields of 57% and 67% against the added PUFAs, respectively. This is the first report of the isolation of a bacterium transforming C20 PUFAs into corresponding non-methylene-interrupted FAs. We further investigated the substrate specificity of the biohydrogenation by this strain and revealed that it can convert two cis double bonds at the ω6 and ω9 positions in various C18 and C20 PUFAs into a trans double bond at the ω7 position. This study should serve to open up the development of novel potentially bioactive PUFAs. PMID:25002034

  15. Inhibition of citrus fungal pathogens by using lactic acid bacteria.

    PubMed

    Gerez, C L; Carbajo, M S; Rollán, G; Torres Leal, G; Font de Valdez, G

    2010-08-01

    The effect of lactic acid bacteria (LAB) on pathogenic fungi was evaluated and the metabolites involved in the antifungal effect were characterized. Penicillium digitatum (INTA 1 to INTA 7) and Geotrichum citri-aurantii (INTA 8) isolated from decayed lemon from commercial packinghouses were treated with imazalil and guazatine to obtain strains resistant to these fungicides. The most resistant strains (4 fungal strains) were selected for evaluating the antifungal activity of 33 LAB strains, among which only 8 strains gave positive results. The antifungal activity of these LAB strains was related to the production of lactic acid, acetic acid, and phenyllactic acid (PLA). A central composite design and the response surface methodology were used to evaluate the inhibitory effect of the organic acids produced by the LAB cultures. The antifungal activity of lactic acid was directly related to its concentration; however, acetic acid and PLA showed a peak of activity at 52.5 and 0.8 mM, respectively, with inhibition rates similar to those obtained with Serenade((R)) (3.0 ppm) imazalil (50 ppm) and guazatine (50 ppm). Beyond the peak of activity, a reduction in effectiveness of both acetic acid and PLA was observed. Comparing the inhibition rate of the organic acids, PLA was about 66- and 600-fold more effective than acetic acid and lactic acid, respectively. This study presents evidences on the antifungal effect of selected LAB strains and their end products. Studies are currently being undertaken to evaluate the effectiveness in preventing postharvest diseases on citrus fruits. PMID:20722936

  16. Fluorometric Determination of Deoxyribonucleic Acid in Bacteria with Ethidium Bromide

    PubMed Central

    Donkersloot, J. A.; Robrish, S. A.; Krichevsky, M. I.

    1972-01-01

    A simple, sensitive, and rapid method is presented for the determination of deoxyribonucleic acid (DNA) in both gram-positive and gram-negative bacteria. It is based upon the fluorometric determination of DNA with ethidium bromide after alkaline digestion of the bacteria to hydrolyze the interfering ribonucleic acid. The assay takes less than 2 hr. Its sensitivity is at least 0.2 μg of DNA in a final solution of 4 ml and it uses commonly available filter or double monochromator fluorometers. Judicious choice of light source and filters allows an additional 10-fold increase in sensitivity with a filter fluorometer. Turbidity caused by bacteria or insoluble polysaccharides does not interfere with the fluorescence measurements. There was no significant difference between the results obtained with this method and those obtained with the indole and diphenylamine methods when these assays were applied to Escherichia coli and sucrose- or glucose-grown Streptococcus mutans. The method was also tested by determining the specific growth rate of E. coli. This new procedure should be especially useful for the determination of bacterial DNA in dilute suspensions and for the estimation of bacterial growth or DNA replication where more conventional methods are not applicable or sensitive enough. PMID:4561101

  17. Affinity sensor using 3-aminophenylboronic acid for bacteria detection.

    PubMed

    Wannapob, Rodtichoti; Kanatharana, Proespichaya; Limbut, Warakorn; Numnuam, Apon; Asawatreratanakul, Punnee; Thammakhet, Chongdee; Thavarungkul, Panote

    2010-10-15

    Boronic acid that can reversibly bind to diols was used to detect bacteria through its affinity binding reaction with diol-groups on bacterial cell walls. 3-aminophenylboronic acid (3-APBA) was immobilized on a gold electrode via a self-assembled monolayer. The change in capacitance of the sensing surface caused by the binding between 3-APBA and bacteria in a flow system was detected by a potentiostatic step method. Under optimal conditions the linear range of 1.5×10(2)-1.5×10(6) CFU ml(-1) and the detection limit of 1.0×10(2) CFU ml(-1) was obtained. The sensing surface can be regenerated and reused up to 58 times. The method was used for the analysis of bacteria in several types of water, i.e., bottled, well, tap, reservoir and wastewater. Compared with the standard plate count method, the results were within one standard deviation of each other. The proposed method can save both time and cost of analysis. The electrode modified with 3-APBA would also be applicable to the detection of other cis-diol-containing analytes. The concept could be extended to other chemoselective ligands, offering less expensive and more robust affinity sensors for a wide range of compounds. PMID:20801635

  18. Biosynthesis of myristic acid in luminescent bacteria. [Vibrio harveyi

    SciTech Connect

    Byers, D.M.

    1987-05-01

    In vivo pulse-label studies have demonstrated that luminescent bacteria can provide myritic acid (14:0) required for the synthesis of the luciferase substrate myristyl aldehyde. Luminescent wild type Vibrio harveyi incubated with (/sup 14/C) acetate in a nutrient-depleted medium accumulated substantial tree (/sup 14/C)fatty acid (up to 20% of the total lipid label). Radio-gas chromatography revealed that > 75% of the labeled fatty acid is 14:0. No free fatty acid was detected in wild type cells labeled prior to the development of bioluminescence in the exponential growth phase, or in a dark mutant of V. harveyi (mutant M17) that requires exogenous 14:0 for light emission. The preferential accumulation of 14:0 was not observed when wild type cells were labeled with (/sup 14/C)acetate in regular growth medium. Moreover, all V. harveyi strains exhibited similar fatty acid mass compositions regardless of the state of bioluminescence. Since earlier work has shown that a luminescence-related acyltransferase (defective in the M17 mutant) can catalyze the deacylation of fatty acyl-acyl carrier protein in vitro, the present results are consistent with a model in which this enzyme diverts 14:0 to the luminescence system during fatty acid biosynthesis. Under normal conditions, the supply of 14:0 by this pathway is tightly regulated such that bioluminescence development does not significantly alter the total fatty acid composition.

  19. Development of xylose-fermenting yeasts for ethanol production at high acetic acid concentrations

    SciTech Connect

    Mohandas, D.V.; Whelan, D.R.; Panchal, C.J.

    1995-12-31

    Mutants resistant to comparatively high levels of acetic acid were isolated from the xylose-fermenting yeasts Candida shehatae and Pichia Stipitis by adapting these cultures to increasing concentrations of acetic acid grown in shake-flask cultures. These mutants were tested for their ability to ferment xylose in presence of high acetic acid concentrations, in acid hydrolysates of wood, and in hardwood spent sulfite liquor, and compared with their wild-type counterparts and between themselves. The P. stipitis mutant exhibited faster fermentation times, better tolerance to acid hydrolysates, and tolerance to lower pH.

  20. Current taxonomy of phages infecting lactic acid bacteria

    PubMed Central

    Mahony, Jennifer; van Sinderen, Douwe

    2013-01-01

    Phages infecting lactic acid bacteria have been the focus of significant research attention over the past three decades. Through the isolation and characterization of hundreds of phage isolates, it has been possible to classify phages of the dairy starter and adjunct bacteria Lactococus lactis, Streptococcus thermophilus, Leuconostoc spp., and Lactobacillus spp. Among these, phages of L. lactis have been most thoroughly scrutinized and serve as an excellent model system to address issues that arise when attempting taxonomic classification of phages infecting other LAB species. Here, we present an overview of the current taxonomy of phages infecting LAB genera of industrial significance, the methods employed in these taxonomic efforts and how these may be employed for the taxonomy of phages of currently underrepresented and emerging phage species. PMID:24478767

  1. Screening and characterization of novel bacteriocins from lactic acid bacteria.

    PubMed

    Zendo, Takeshi

    2013-01-01

    Bacteriocins produced by lactic acid bacteria (LAB) are expected to be safe antimicrobial agents. While the best studied LAB bacteriocin, nisin A, is widely utilized as a food preservative, various novel ones are required to control undesirable bacteria more effectively. To discover novel bacteriocins at the early step of the screening process, we developed a rapid screening system that evaluates bacteriocins produced by newly isolated LAB based on their antibacterial spectra and molecular masses. By means of this system, various novel bacteriocins were identified, including a nisin variant, nisin Q, a two-peptide bacteriocin, lactococcin Q, a leaderless bacteriocin, lacticin Q, and a circular bacteriocin, lactocyclicin Q. Moreover, some LAB isolates were found to produce multiple bacteriocins. They were characterized as to their structures, mechanisms of action, and biosynthetic mechanisms. Novel LAB bacteriocins and their biosynthetic mechanisms are expected for applications such as food preservation and peptide engineering. PMID:23649268

  2. Development of Mucosal Vaccines Based on Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Bermúdez-Humarán, Luis G.; Innocentin, Silvia; Lefèvre, Francois; Chatel, Jean-Marc; Langella, Philippe

    Today, sufficient data are available to support the use of lactic acid bacteria (LAB), notably lactococci and lactobacilli, as delivery vehicles for the development of new mucosal vaccines. These non-pathogenic Gram-positive bacteria have been safely consumed by humans for centuries in fermented foods. They thus constitute an attractive alternative to the attenuated pathogens (most popular live vectors actually studied) which could recover their pathogenic potential and are thus not totally safe for use in humans. This chapter reviews the current research and advances in the use of LAB as live delivery vectors of proteins of interest for the development of new safe mucosal vaccines. The use of LAB as DNA vaccine vehicles to deliver DNA directly to antigen-presenting cells of the immune system is also discussed.

  3. Natural selection for 2,4,5-trichlorophenoxyacetic acid mineralizing bacteria in agent orange contaminated soil.

    PubMed

    Rice, J F; Menn, F M; Hay, A G; Sanseverino, J; Sayler, G S

    2005-12-01

    Agent Orange contaminated soils were utilized in direct enrichment culture studies to isolate 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and 2,4-dichlorophenoxyacetic acid (2,4-D) mineralizing bacteria. Two bacterial cultures able to grow at the expense of 2,4,5-T and/or 2,4-D were isolated. The 2,4,5-T degrading culture was a mixed culture containing two bacteria, Burkholderia species strain JR7B2 and Burkholderia species strain JR7B3. JR7B3 was able to metabolize 2,4,5-T as the sole source of carbon and energy, and demonstrated the ability to affect metabolism of 2,4-D to a lesser degree. Strain JR7B3 was able to mineralize 2,4,5-T in pure culture and utilized 2,4,5-T in the presence of 0.01% yeast extract. Subsequent characterization of the 2,4-D degrading culture showed that one bacterium, Burkholderia species strain JRB1, was able to utilize 2,4-D as a sole carbon and energy source in pure culture. Polymerase chain reaction (PCR) experiments utilizing known genetic sequences from other 2,4-D and 2,4,5-T degrading bacteria demonstrated that these organisms contain gene sequences similar to tfdA, B, C, E, and R (Strain JRB1) and the tftA, C, and E genes (Strain JR7B3). Expression analysis confirmed that tftA, C, and E and tfdA, B, and C were transcribed during 2,4,5-T and 2,4-D dependent growth, respectively. The results indicate a strong selective pressure for 2,4,5-T utilizing strains under field condition. PMID:15865343

  4. Fermentation of aqueous plant seed extracts by lactic acid bacteria

    SciTech Connect

    Schafner, D.W.; Beuchat, R.L.

    1986-05-01

    The effects of lactic acid bacterial fermentation on chemical and physical changes in aqueous extracts of cowpea (Vigna unguiculata), peanut (Arachis hypogea), soybean (Glycine max), and sorghum (Sorghum vulgare) were studied. The bacteria investigated were Lactobacillus helveticus, L. delbrueckii, L. casei, L. bulgaricus, L. acidophilus, and Streptococcus thermophilus. Organisms were inoculated individually into all of the seed extracts; L. bulgaricus and S. thermophilus were also evaluated together as inocula for fermenting the legume extracts. During fermentation, bacterial population and changes in titratable acidity, pH, viscosity, and color were measured over a 72 h period at 37 degrees C. Maximum bacterial populations, titratable acidity, pH, and viscosity varied depending upon the type of extract and bacterial strain. The maximum population of each organism was influenced by fermentable carbohydrates, which, in turn, influenced acid production and change in pH. Change in viscosity was correlated with the amount of protein and titratable acidity of products. Color was affected by pasteurization treatment and fermentation as well as the source of extract. In the extracts inoculated simultaneously with L. bulgaricus and S. thermophilus, a synergistic effect resulted in increased bacterial populations, titratable acidity, and viscosity, and decreased pH in all the legume extracts when compared to the extracts fermented with either of these organisms individually. Fermented extracts offer potential as substitutes for cultured dairy products. 24 references.

  5. Metabolic strategies of beer spoilage lactic acid bacteria in beer.

    PubMed

    Geissler, Andreas J; Behr, Jürgen; von Kamp, Kristina; Vogel, Rudi F

    2016-01-01

    Beer contains only limited amounts of readily fermentable carbohydrates and amino acids. Beer spoilage lactic acid bacteria (LAB) have to come up with metabolic strategies in order to deal with selective nutrient content, high energy demand of hop tolerance mechanisms and a low pH. The metabolism of 26 LAB strains of 6 species and varying spoilage potentialwas investigated in order to define and compare their metabolic capabilities using multivariate statistics and outline possible metabolic strategies. Metabolic capabilities of beer spoilage LAB regarding carbohydrate and amino acids did not correlate with spoilage potential, but with fermentation type (heterofermentative/homofermentative) and species. A shift to mixed acid fermentation by homofermentative (hof) Pediococcus claussenii and Lactobacillus backii was observed as a specific feature of their growth in beer. For heterofermentative (hef) LAB a mostly versatile carbohydrate metabolism could be demonstrated, supplementing the known relevance of organic acids for their growth in beer. For hef LAB a distinct amino acid metabolism, resulting in biogenic amine production, was observed, presumably contributing to energy supply and pH homeostasis. PMID:26398285

  6. Occurrence and role of lactic acid bacteria in seafood products.

    PubMed

    Françoise, Leroi

    2010-09-01

    Lactic acid bacteria (LAB) in fish flesh has long been disregarded because the high post-mortem pH, the low percentage of sugars, the high content of low molecular weight nitrogenous molecules and the low temperature of temperate waters favor the rapid growth of pH-sensitive psychrotolerant marine Gram-negative bacteria like Pseudomonas, Shewanella and Photobacterium. In seafood packed in both vacuum (VP) and modified atmosphere (MAP) packaging commonly CO(2) enriched, the growth of the Gram-negative aerobic bacteria group (predominantly pseudomonads) is effectively inhibited and the number reached by LAB during storage is higher than that achieved in air but always several log units lower than the trimethylamine oxide (TMA-O) reducing and CO(2)-resistant organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Accordingly, LAB are not of much concern in seafood neither aerobically stored nor VP and MAP. However, they may acquire great relevance in lightly preserved fish products (LPFP), including those VP or MAP. Fresh fish presents a very high water activity (aw) value (0.99). However, aw is reduced to about 0.96 when salt (typically 6% WP) is added to the product. As a result, aerobic Gram-negative bacteria are inhibited, which allows the growth of other organisms more resistant to reduced aw, i.e. LAB, and then they may acquire a central role in the microbial events occurring in the product. Changes in consumers' habits have led to an increase of convenient LPFP with a relative long shelf-life (at least 3 weeks) which, on the other hand, may constitute a serious problem from a safety perspective since Listeria monocytogenes and sometimes Clostridium botulinum (mainly type E) may able to grow. In any case the LAB function in marine products is complex, depending on species, strains, interaction with other bacteria and the food matrix. They may have no particular effect or they may be responsible for spoilage and, in certain cases, they may even exert

  7. Genomic reconstruction of transcriptional regulatory networks in lactic acid bacteria

    PubMed Central

    2013-01-01

    Background Genome scale annotation of regulatory interactions and reconstruction of regulatory networks are the crucial problems in bacterial genomics. The Lactobacillales order of bacteria collates various microorganisms having a large economic impact, including both human and animal pathogens and strains used in the food industry. Nonetheless, no systematic genome-wide analysis of transcriptional regulation has been previously made for this taxonomic group. Results A comparative genomics approach was used for reconstruction of transcriptional regulatory networks in 30 selected genomes of lactic acid bacteria. The inferred networks comprise regulons for 102 orthologous transcription factors (TFs), including 47 novel regulons for previously uncharacterized TFs. Numerous differences between regulatory networks of the Streptococcaceae and Lactobacillaceae groups were described on several levels. The two groups are characterized by substantially different sets of TFs encoded in their genomes. Content of the inferred regulons and structure of their cognate TF binding motifs differ for many orthologous TFs between the two groups. Multiple cases of non-orthologous displacements of TFs that control specific metabolic pathways were reported. Conclusions The reconstructed regulatory networks substantially expand the existing knowledge of transcriptional regulation in lactic acid bacteria. In each of 30 studied genomes the obtained regulatory network contains on average 36 TFs and 250 target genes that are mostly involved in carbohydrate metabolism, stress response, metal homeostasis and amino acids biosynthesis. The inferred networks can be used for genetic experiments, functional annotations of genes, metabolic reconstruction and evolutionary analysis. All reconstructed regulons are captured within the Streptococcaceae and Lactobacillaceae collections in the RegPrecise database (http://regprecise.lbl.gov). PMID:23398941

  8. Nitrile Metabolizing Yeasts

    NASA Astrophysics Data System (ADS)

    Bhalla, Tek Chand; Sharma, Monica; Sharma, Nitya Nand

    Nitriles and amides are widely distributed in the biotic and abiotic components of our ecosystem. Nitrile form an important group of organic compounds which find their applications in the synthesis of a large number of compounds used as/in pharmaceutical, cosmetics, plastics, dyes, etc>. Nitriles are mainly hydro-lyzed to corresponding amide/acid in organic chemistry. Industrial and agricultural activities have also lead to release of nitriles and amides into the environment and some of them pose threat to human health. Biocatalysis and biotransformations are increasingly replacing chemical routes of synthesis in organic chemistry as a part of ‘green chemistry’. Nitrile metabolizing organisms or enzymes thus has assumed greater significance in all these years to convert nitriles to amides/ acids. The nitrile metabolizing enzymes are widely present in bacteria, fungi and yeasts. Yeasts metabolize nitriles through nitrilase and/or nitrile hydratase and amidase enzymes. Only few yeasts have been reported to possess aldoxime dehydratase. More than sixty nitrile metabolizing yeast strains have been hither to isolated from cyanide treatment bioreactor, fermented foods and soil. Most of the yeasts contain nitrile hydratase-amidase system for metabolizing nitriles. Transformations of nitriles to amides/acids have been carried out with free and immobilized yeast cells. The nitrilases of Torulopsis candida>and Exophiala oligosperma>R1 are enantioselec-tive and regiospecific respectively. Geotrichum>sp. JR1 grows in the presence of 2M acetonitrile and may have potential for application in bioremediation of nitrile contaminated soil/water. The nitrilase of E. oligosperma>R1 being active at low pH (3-6) has shown promise for the hydroxy acids. Immobilized yeast cells hydrolyze some additional nitriles in comparison to free cells. It is expected that more focus in future will be on purification, characterization, cloning, expression and immobilization of nitrile metabolizing

  9. Overview on mechanisms of acetic acid resistance in acetic acid bacteria.

    PubMed

    Wang, Bin; Shao, Yanchun; Chen, Fusheng

    2015-02-01

    Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided. PMID:25575804

  10. Halotolerance and survival kinetics of lactic acid bacteria isolated from jalapeño pepper (Capsicum annuum L.) fermentation.

    PubMed

    González-Quijano, Génesis Karendash; Dorantes-Alvarez, Lidia; Hernández-Sánchez, Humberto; Jaramillo-Flores, María Eugenia; de Jesús Perea-Flores, María; Vera-Ponce de León, Arturo; Hernández-Rodríguez, César

    2014-08-01

    The microbiota associated with spontaneous fermentation of vegetables in a saline substrate may represent an important group of bacteria in the food industry. In this work, the lactic acid bacteria (LAB) Weissella cibaria, Lactobacillus plantarum, Lactobacillus paraplantarum, and Leuconostoc citreum were identified by partial 16S rRNA gene sequence analysis. In addition, entophytic bacteria such as Pantoea eucalypti, Pantoea anthophila, Enterobacter cowanii, and Enterobacter asburiae were detected, but they were irrelevant for the fermentation process and were inhibited after 12 h of fermentation when the pH decreased from 6.5 to 4.9. Moreover, 2 species of yeast were isolated and identified as Hanseniaspora pseudoguilliermondii and Kodamaea ohmeri by their partial 26S rRNA gene sequence. The growth of LAB was evaluated at different sodium chloride contents. L. citreum was the most halotolerant species followed by L. plantarum and W. cibaria with a concentration index to obtain a 50% population reduction (IC(50)) of 7.2%, 6.6%, and 5.2%, respectively. Furthermore, the growth of LAB and Escherichia coli O157:H7 was evaluated in the presence of the main phenylpropanoids from chilli peppers such as p-coumaric and ferulic acid. It was determined that LAB can grow in both acids at 4 mM, unlike E. coli O157:H7, whose growth is inhibited in the presence of these acids. PMID:25039289

  11. Genome level analysis of bacteriocins of lactic acid bacteria.

    PubMed

    Singh, Neetigyata Pratap; Tiwari, Abhay; Bansal, Ankiti; Thakur, Shruti; Sharma, Garima; Gabrani, Reema

    2015-06-01

    Bacteriocins are antimicrobial peptides which are ribosomally synthesized by mainly all bacterial species. LABs (lactic acid bacteria) are a diverse group of bacteria that include around 20 genera of various species. Though LABs have a tremendous potential for production of anti-microbial peptides, this group of bacteria is still underexplored for bacteriocins. To study the diversity among bacteriocin encoding clusters and the putative bacteriocin precursors, genome mining was performed on 20 different species of LAB not reported to be bacteriocin producers. The phylogenetic tree of gyrB, rpoB, and 16S rRNA were constructed using MEGA6 software to analyze the diversity among strains. Putative bacteriocins operons identified were found to be diverse and were further characterized on the basis of physiochemical properties and the secondary structure. The presence of at least two cysteine residues in most of the observed putative bacteriocins leads to disulphide bond formation and provide stability. Our data suggests that LABs are prolific source of low molecular weight non modified peptides. PMID:25733445

  12. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    PubMed Central

    Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Troncoso, Ana M.; Garcia-Parrilla, M. Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements. PMID:24895623

  13. Naturally occurring lactic Acid bacteria isolated from tomato pomace silage.

    PubMed

    Wu, Jing-Jing; Du, Rui-Ping; Gao, Min; Sui, Yao-Qiang; Xiu, Lei; Wang, Xiao

    2014-05-01

    Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage. PMID:25049999

  14. Naturally Occurring Lactic Acid Bacteria Isolated from Tomato Pomace Silage

    PubMed Central

    Wu, Jing-jing; Du, Rui-ping; Gao, Min; Sui, Yao-qiang; Xiu, Lei; Wang, Xiao

    2014-01-01

    Silage making has become a significant method of forage conservation worldwide. To determine how tomato pomace (TP) may be used effectively as animal feed, it was ensilaged for 90 days and microbiology counts, fermentation characteristics and chemical composition of tomato pomace silage (TPS) were evaluated at the 30th, 60th, and 90th days, respectively. In addition, 103 lactic acid bacteria were isolated from TPS. Based on the phenotypic and chemotaxonomic characteristics, 16S rDNA sequence and carbohydrate fermentation tests, the isolates were identified as 17 species namely: Lactobacillus coryniformis subsp. torquens (0.97%), Lactobacillus pontis (0.97%), Lactobacillus hilgardii (0.97%), Lactobacillus pantheris (0.97%), Lactobacillus amylovorus (1.9%), Lactobacillus panis (1.9%), Lactobacillus vaginalis (1.9%), Lactobacillus rapi (1.9%), Lactobacillus buchneri (2.9%), Lactobacillus parafarraginis (2.9%), Lactobacillus helveticus (3.9%), Lactobacillus camelliae (3.9%), Lactobacillus fermentum (5.8%), Lactobacillus manihotivorans (6.8%), Lactobacillus plantarum (10.7%), Lactobacillus harbinensis (16.5%) and Lactobacillus paracasei subsp. paracasei (35.0%). This study has shown that TP can be well preserved for 90 days by ensilaging and that TPS is not only rich in essential nutrients, but that physiological and biochemical properties of the isolates could provide a platform for future design of lactic acid bacteria (LAB) inoculants aimed at improving the fermentation quality of silage. PMID:25049999

  15. Boric acid-dependent decrease in regulatory histone H3 acetylation is not mutagenic in yeast.

    PubMed

    Pointer, Benjamin R; Schmidt, Martin

    2016-07-01

    Candida albicans is a dimorphic yeast commonly found on human mucosal membranes that switches from yeast to hyphal morphology in response to environmental factors. The change to hyphal growth requires histone H3 modifications by the yeast-specific histone acetyltransferase Rtt109. In addition to its role in morphogenesis, Rtt109-dependent acetylation of histone H3 lysine residues 9 and 56 has regulatory functions during DNA replication and repair. Boric acid (BA) is a broad-spectrum agent that specifically inhibits C. albicans hyphal growth, locking the fungus in its harmless commensal yeast state. The present study characterizes the effect of BA on C. albicans histone acetylation in respect to specificity, time-course and significance. We demonstrate that sublethal concentrations of BA reduce H3K9/H3K56 acetylation, both on a basal level and in response to genotoxic stress. Acetylation at other selected histone sites were not affected by BA. qRT-PCR expression analysis of the DNA repair gene Rad51 indicated no elevated level of genotoxic stress during BA exposure. A forward-mutation analysis demonstrated the BA does not increase spontaneous or induced mutations. The findings suggest that DNA repair remains effective even when histone H3 acetylation decreases and dispels the notion that BA treatment impairs genome integrity in yeast. PMID:27190149

  16. Manipulation of culture conditions alters lipid content and fatty acid profiles of a wide variety of known and new oleaginous yeasts species

    PubMed Central

    Sitepu, Irnayuli R.; Sestric, Ryan; Ignatia, Laura; Levin, David; German, J. Bruce; Gillies, Laura A.; Almada, Luis A.G.; Boundy-Mills, Kyria L.

    2013-01-01

    Oleaginous yeasts have been studied for oleochemical production for over 80 years. Only a few species have been studied intensely. To expand the diversity of oleaginous yeasts available for lipid research, we surveyed a broad diversity of yeasts with indicators of oleaginicity including known oleaginous clades, and buoyancy. Sixty-nine strains representing 17 genera and 50 species were screened for lipid production. Yeasts belonged to Ascomycota families, Basidiomycota orders, and the yeast-like algal genus Prototheca. Total intracellular lipids and fatty acid composition were determined under different incubation times and nitrogen availability. Thirteen new oleaginous yeast species were discovered, representing multiple ascomycete and basidiomycete clades. Nitrogen starvation generally increased intracellular lipid content. The fatty acid profiles varied with the growth conditions regardless of taxonomic affiliation. The dominant fatty acids were oleic acid, palmitic acid, linoleic acid, and stearic acid. Yeasts and culture conditions that produced fatty acids appropriate for biodiesel were identified. PMID:23891835

  17. Protection of live bacteria from bile acid toxicity using bile acid adsorbing resins.

    PubMed

    Edwards, Alexander D; Slater, Nigel K H

    2009-06-12

    We previously demonstrated that a dry, room temperature stable formulation of a live bacterial vaccine was highly susceptible to bile, and suggested that this will lead to significant loss of viability of any live bacterial formulation released into the intestine using an enteric coating or capsule. We found that bile and acid tolerance is very rapidly recovered after rehydration with buffer or water, raising the possibility that rehydration in the absence of bile prior to release into the intestine might solve the problem of bile toxicity to dried cells. We describe here a novel formulation that combines extensively studied bile acid adsorbent resins with the dried bacteria, to temporarily adsorb bile acids and allow rehydration and recovery of bile resistance of bacteria in the intestine before release. Tablets containing the bile acid adsorbent cholestyramine release 250-fold more live bacteria when dissolved in a bile solution, compared to control tablets without cholestyramine or with a control resin that does not bind bile acids. We propose that a simple enteric coated oral dosage form containing bile acid adsorbent resins will allow improved live bacterial delivery to the intestine via the oral route, a major step towards room temperature stable, easily administered and distributed vaccine pills and other bacterial therapeutics. PMID:19490986

  18. Insights into the evolution of sialic acid catabolism among bacteria

    PubMed Central

    Almagro-Moreno, Salvador; Boyd, E Fidelma

    2009-01-01

    Background Sialic acids comprise a family of nine-carbon amino sugars that are prevalent in mucus rich environments. Sialic acids from the human host are used by a number of pathogens as an energy source. Here we explore the evolution of the genes involved in the catabolism of sialic acid. Results The cluster of genes encoding the enzymes N-acetylneuraminate lyase (NanA), epimerase (NanE), and kinase (NanK), necessary for the catabolism of sialic acid (the Nan cluster), are confined 46 bacterial species, 42 of which colonize mammals, 33 as pathogens and 9 as gut commensals. We found a putative sialic acid transporter associated with the Nan cluster in most species. We reconstructed the phylogenetic history of the NanA, NanE, and NanK proteins from the 46 species and compared them to the species tree based on 16S rRNA. Within the NanA phylogeny, Gram-negative and Gram-positive bacteria do not form distinct clades. NanA from Yersinia and Vibrio species was most closely related to the NanA clade from eukaryotes. To examine this further, we reconstructed the phylogeny of all NanA homologues in the databases. In this analysis of 83 NanA sequences, Bacteroidetes, a human commensal group formed a distinct clade with Verrucomicrobia, and branched with the Eukaryotes and the Yersinia/Vibrio clades. We speculate that pathogens such as V. cholerae may have acquired NanA from a commensal aiding their colonization of the human gut. Both the NanE and NanK phylogenies more closely represented the species tree but numerous incidences of incongruence are noted. We confirmed the predicted function of the sialic acid catabolism cluster in members the major intestinal pathogens Salmonella enterica, Vibrio cholerae, V. vulnificus, Yersinia enterocolitica and Y. pestis. Conclusion The Nan cluster among bacteria is confined to human pathogens and commensals conferring them the ability to utilize a ubiquitous carbon source in mucus rich surfaces of the human body. The Nan region shows a

  19. Control of spoilage fungi by protective lactic acid bacteria displaying probiotic properties.

    PubMed

    Varsha, Kontham Kulangara; Priya, Sulochana; Devendra, Leena; Nampoothiri, Kesavan Madhavan

    2014-04-01

    Thirty-six lactic acid bacteria belong to Lactococcus, Lactobacillus, Enterococcus, and Pediococcus were isolated, and the spectrum of antifungal activity was verified against Fusarium oxysporum (KACC 42109), Aspergillus niger (KACC 42589), Fusarium moniliforme (KACC 08141), Penicillium chrysogenum (NII 08137), and the yeast Candida albicans (MTCC 3017). Three isolates, identified as Pediococcus pentosaceus (TG2), Lactobacillus casei (DY2), and Lactococcus (BSN) were selected further, and their antifungal compounds were identified by ESI-MS and HPLC analysis as a range of carboxylic acids along with some unidentified, higher molecular weight compounds. An attempt to check out the shelf life extension of wheat bread without fungal spoilage was performed by fermenting the dough with the Lactococcus isolate. Apart from growth in low pH and tolerance to bile salts, probiotic potential of these three isolates was further substantiated by in vitro screening methods that include transit tolerance to the conditions in the upper human gastrointestinal tract and bacterial adhesion capacity to human intestinal cell lines. PMID:24532445

  20. Recent advances in nitrogen-fixing acetic acid bacteria.

    PubMed

    Pedraza, Raúl O

    2008-06-30

    Nitrogen is an essential plant nutrient, widely applied as N-fertilizer to improve yield of agriculturally important crops. An interesting alternative to avoid or reduce the use of N-fertilizers could be the exploitation of plant growth-promoting bacteria (PGPB), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. PGPB belong to diverse genera, including Azospirillum, Azotobacter, Herbaspirillum, Bacillus, Burkholderia, Pseudomonas, Rhizobium, and Gluconacetobacter, among others. They are capable of promoting plant growth through different mechanisms including (in some cases), the biological nitrogen fixation (BNF), the enzymatic reduction of the atmospheric dinitrogen (N(2)) to ammonia, catalyzed by nitrogenase. Aerobic bacteria able to oxidize ethanol to acetic acid in neutral or acid media are candidates of belonging to the family Acetobacteraceae. At present, this family has been divided into ten genera: Acetobacter, Gluconacetobacter, Gluconobacter, Acidomonas, Asaia, Kozakia, Saccharibacter, Swaminathania, Neoasaia, and Granulibacter. Among them, only three genera include N(2)-fixing species: Gluconacetobacter, Swaminathania and Acetobacter. The first N(2)-fixing acetic acid bacterium (AAB) was described in Brazil. It was found inside tissues of the sugarcane plant, and first named as Acetobacter diazotrophicus, but then renamed as Gluconacetobacter diazotrophicus. Later, two new species within the genus Gluconacetobacter, associated to coffee plants, were described in Mexico: G. johannae and G. azotocaptans. A salt-tolerant bacterium named Swaminathania salitolerans was found associated to wild rice plants. Recently, N(2)-fixing Acetobacter peroxydans and Acetobacter nitrogenifigens, associated with rice plants and Kombucha tea, respectively, were described in India. In this paper, recent advances involving nitrogen-fixing AAB are presented. Their natural habitats, physiological and genetic aspects

  1. Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass

    PubMed Central

    Kolouchová, Irena; Maťátková, Olga; Sigler, Karel; Masák, Jan; Řezanka, Tomáš

    2016-01-01

    We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70. PMID:27022398

  2. Effects of varying media, temperature, and growth rates on the intracellular concentrations of yeast amino acids.

    PubMed

    Martínez-Force, E; Benítez, T

    1995-01-01

    Variations of the yeast free amino acid pool under different culture conditions were studied in two Saccharomyces strains, the laboratory haploid strain S288C and the industrial fermentative yeast IFI256. The internal amino acid pool of both strains was measured when grown in laboratory (minimal and complete) versus semiindustrial (molasses with or without added biotin and/or diammonium phosphate) media, in fermentable (glucose, fructose, sucrose) versus respirable (glycerol) carbon sources, in different temperatures (22, 30, and 37 degrees C), pHs (2.0-4.75), and growth rates (0.018-0.24 h-1) in continuous culture, and at different phases of the growth curve in batch culture (lag, exponential, early and late stationary). Results indicated that environmental conditions, particularly the presence of amino acids in the media, enormously influenced the intracellular amino acid concentration. Higher values were detected in molasses than in laboratory media and in fermentable carbon sources (glucose, fructose, sucrose) than in glycerol. Variations in the amino acid pool along the growth curve were greater at 37 degrees C than at other temperatures; in all cases, the highest values were measured at the beginning of the exponential phase. In continuous culture and at different growth rates, intracellular free amino acid concentrations increased by 3-10-fold when the growth rate was lower than 0.05 h-1, representing 20-35% of the total (free plus protein) amino acid content and indicating that amino acid yield was a partly growth-linked parameter. PMID:7654310

  3. Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass.

    PubMed

    Kolouchová, Irena; Maťátková, Olga; Sigler, Karel; Masák, Jan; Řezanka, Tomáš

    2016-01-01

    We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70-90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70. PMID:27022398

  4. Lipid and citric acid production by wild yeasts grown in glycerol.

    PubMed

    Souza, Karla Silva Teixeira; Schwan, Rosane Freitas; Dias, Disney Ribeiro

    2014-04-01

    In this study, crude glycerol was used as a carbon source in the cultivation of wild yeasts, aiming for the production of microbial lipids and citric acid. Forty yeasts of different sources were tested concerning their growth in crude and commercial glycerol. Four yeasts (Lidnera saturnus UFLA CES-Y677, Yarrowia lipolytica UFLA CM-Y9.4, Rhodotorula glutinis NCYC 2439, and Cryptococcus curvatus NCYC 476) were then selected owing to their ability to grow in pure (OD600 2.133, 1.633, 2.055, and 2.049, respectively) and crude (OD600 2.354, 1.753, 2.316, and 2.281, respectively) glycerol (10%, 20%, and 30%). Y. lipolytica UFLA CM-Y9.4 was selected for its ability to maintain cell viability in concentrations of 30% of crude glycerol, and high glycerol intake (18.907 g/l). This yeast was submitted to lipid production in 30 g/l of crude glycerol, and therefore obtained 63.4% of microbial lipids. In the fatty acid profile, there was a predominance of stearic (C18:0) and palmitic (C16:0) acids in the concentrations of 87.64% and 74.67%, respectively. We also performed optimization of the parameters for the production of citric acid, which yielded a production of 0.19 g/l of citric acid in optimum conditions (38.4 g/l of crude glycerol, agitation of 184 rpm, and temperature of 30°C). Yarrowia lipolytica UFLA CM-Y9.4 presented good lipid production when in the concentration of 30 g/l of glycerol. These data may be used for production in large quantities for the application of industrial biodiesel. PMID:24473455

  5. Bioconversion of R-(+)-limonene to perillic acid by the yeast Yarrowia lipolytica

    PubMed Central

    Ferrara, Maria Antonieta; Almeida, Débora S.; Siani, Antonio C.; Lucchetti, Leonardo; Lacerda, Paulo S.B.; Freitas, André; Tappin, Marcelo R.R.; Bon, Elba P.S.

    2013-01-01

    Perillyl derivatives are increasingly important due to their flavouring and antimicrobial properties as well as their potential as anticancer agents. These terpenoid species, which are present in limited amounts in plants, may be obtained via bioconversion of selected monoterpene hydrocarbons. In this study, seventeen yeast strains were screened for their ability to oxidize the exocyclic methyl group in the p-menthene moiety of limonene into perillic acid. Of the yeast tested, the highest efficiency was observed for Yarrowia lipolytica ATCC 18942. The conversion of R (+)-limonene by Y. lipolytica was evaluated by varying the pH (3 to 8) and the temperature (25 to 30 °C) in a reaction medium containing 0.5% v/v limonene and 10 g/L of stationary phase cells (dry weight). The best results, corresponding to 564 mg/L of perillic acid, were obtained in buffered medium at pH 7.1 that was incubated at 25 °C for 48 h. The stepwise addition of limonene increased the perillic acid concentration by over 50%, reaching 855 mg/L, whereas the addition of glucose or surfactant to the reaction medium did not improve the bioconversion process. The use of Y. lipolytica showed promise for ease of further downstream processing, as perillic acid was the sole oxidised product of the bioconversion reaction. Moreover, bioprocesses using safe and easy to cultivate yeast cells have been favoured in industry. PMID:24688495

  6. De novo synthesis of trans-10, cis-12 conjugated linoleic acid in oleaginous yeast Yarrowia Lipolytica

    PubMed Central

    2012-01-01

    Background Conjugated linoleic acid (CLA) has many well-documented beneficial physiological effects. Due to the insufficient natural supply of CLA and low specificity of chemically produced CLA, an effective and isomer-specific production process is required for medicinal and nutritional purposes. Results The linoleic acid isomerase gene from Propionibacterium acnes was expressed in Yarrowia lipolytica Polh. Codon usage optimization of the PAI and multi-copy integration significantly improved the expression level of PAI in Y. lipolytica. The percentage of trans-10, cis-12 CLA was six times higher in yeast carrying the codon-optimized gene than in yeast carrying the native gene. In combination with multi-copy integration, the production yield was raised to approximately 30-fold. The amount of trans-10, cis-12 CLA reached 5.9% of total fatty acid yield in transformed Y. lipolytica. Conclusions This is the first report of production of trans-10, cis-12 CLA by the oleaginous yeast Y. lipolytica, using glucose as the sole carbon source through expression of linoleic acid isomerase from Propionibacterium acnes. PMID:22545818

  7. Purification Techniques of Bacteriocins from Lactic Acid Bacteria and Other Gram-Positive Bacteria

    NASA Astrophysics Data System (ADS)

    Saavedra, Lucila; Sesma, Fernando

    The search for new antimicrobial peptides produced by lactic acid ­bacteria and other Gram-positive microorganisms has become an interesting field of research in the past decades. The fact that bacteriocins are active against numerous foodborne and human pathogens, are produced by generally regarded as safe (GRAS) microorganisms, and are readily degraded by proteolytic host systems makes them attractive candidates for biotechnological applications. However, before suggesting or choosing a new bacteriocin for future technology developments, it is necessary to elucidate its biochemical structure and its mode of action, which may be carried out once the bacteriocin is purified to homogeneity. This chapter focuses on describing the main strategies used for the purification of numerous bacteriocins.

  8. Epiphytic bacteria and yeasts on apple blossoms and their potential as antagonists of Erwinia amylovora

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apple blossoms were sampled for indigenous epiphytic populations of culturable microorganisms during different stages of bloom at two orchards in or near Wenatchee, WA, and one in Corvallis, OR. Frequencies and population sizes of bacteria on stigmas of apple were lower at Wenatchee than Corvallis, ...

  9. Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives.

    PubMed

    Rokop, Z P; Horton, M A; Newton, I L G

    2015-10-01

    In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific "core" members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of "noncore" and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited. PMID:26253685

  10. Interactions between Cooccurring Lactic Acid Bacteria in Honey Bee Hives

    PubMed Central

    Rokop, Z. P.; Horton, M. A.

    2015-01-01

    In contrast to the honey bee gut, which is colonized by a few characteristic bacterial clades, the hive of the honey bee is home to a diverse array of microbes, including many lactic acid bacteria (LAB). In this study, we used culture, combined with sequencing, to sample the LAB communities found across hive environments. Specifically, we sought to use network analysis to identify microbial hubs sharing nearly identical operational taxonomic units, evidence which may indicate cooccurrence of bacteria between environments. In the process, we identified interactions between noncore bacterial members (Fructobacillus and Lactobacillaceae) and honey bee-specific “core” members. Both Fructobacillus and Lactobacillaceae colonize brood cells, bee bread, and nectar and may serve the role of pioneering species, establishing an environment conducive to the inoculation by honey bee core bacteria. Coculture assays showed that these noncore bacterial members promote the growth of honey bee-specific bacterial species. Specifically, Fructobacillus by-products in spent medium supported the growth of the Firm-5 honey bee-specific clade in vitro. Metabolic characterization of Fructobacillus using carbohydrate utilization assays revealed that this strain is capable of utilizing the simple sugars fructose and glucose, as well as the complex plant carbohydrate lignin. We tested Fructobacillus for antibiotic sensitivity and found that this bacterium, which may be important for establishment of the microbiome, is sensitive to the commonly used antibiotic tetracycline. Our results point to the possible significance of “noncore” and environmental microbial community members in the modulation of honey bee microbiome dynamics and suggest that tetracycline use by beekeepers should be limited. PMID:26253685

  11. Immunomodulation of monocytes by probiotic and selected lactic Acid bacteria.

    PubMed

    Jensen, Hanne; Drømtorp, Signe Marie; Axelsson, Lars; Grimmer, Stine

    2015-03-01

    Some lactic acid bacteria (LAB), especially bacteria belonging to the genus Lactobacillus, are recognized as common inhabitants of the human gastrointestinal tract and have received considerable attention in the last decades due to their postulated health-promoting effects. LAB and probiotic bacteria can modulate the host immune response. However, much is unknown about the mediators and mechanisms responsible for their immunological effect. Here, we present a study using cytokine secretion from the monocytic cell line THP-1 and NF-κB activation in the monocytic cell line U937-3xkB-LUC to elucidate immune stimulating abilities of LAB in vitro. In this study, we investigate both commercially available and potential probiotic LAB strains, and the role of putative surface proteins of L. reuteri using mutants. L. reuteri strains induced the highest cytokine secretion and the highest NF-κB activation, whereas L. plantarum strains and L. rhamnosus GG were low inducers/activators. One of the putative L. reuteri surface proteins, Hmpref0536_10802, appeared to be of importance for the stimulation of THP-1 cells and the activation of NF-κB in U937-3xkB-LUC cells. Live and UV-inactivated preparations resulted in different responses for two of the strains investigated. Our results add to the complexity in the interaction between LAB and human cells and suggest the possible involvement of secreted pro- and anti-inflammatory mediators of LAB. It is likely that it is the sum of bacterial surface proteins and bacterial metabolites and/or secreted proteins that induce cytokine secretion in THP-1 cells and activate NF-κB in U937-3xkB-LUC cells in this study. PMID:25331988

  12. Indole-3-Acetic Acid-Producing Yeasts in the Phyllosphere of the Carnivorous Plant Drosera indica L

    PubMed Central

    Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

    2014-01-01

    Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

  13. Indole-3-acetic acid-producing yeasts in the phyllosphere of the carnivorous plant Drosera indica L.

    PubMed

    Sun, Pei-Feng; Fang, Wei-Ta; Shin, Li-Ying; Wei, Jyuan-Yu; Fu, Shih-Feng; Chou, Jui-Yu

    2014-01-01

    Yeasts are widely distributed in nature and exist in association with other microorganisms as normal inhabitants of soil, vegetation, and aqueous environments. In this study, 12 yeast strains were enriched and isolated from leaf samples of the carnivorous plant Drosera indica L., which is currently threatened because of restricted habitats and use in herbal industries. According to similarities in large subunit and small subunit ribosomal RNA gene sequences, we identified 2 yeast species in 2 genera of the phylum Ascomycota, and 5 yeast species in 5 genera of the phylum Basidiomycota. All of the isolated yeasts produced indole-3-acetic acid (IAA) when cultivated in YPD broth supplemented with 0.1% L-tryptophan. Growth conditions, such as the pH and temperature of the medium, influenced yeast IAA production. Our results also suggested the existence of a tryptophan-independent IAA biosynthetic pathway. We evaluated the effects of various concentrations of exogenous IAA on yeast growth and observed that IAA produced by wild yeasts modifies auxin-inducible gene expression in Arabidopsis. Our data suggest that yeasts can promote plant growth and support ongoing prospecting of yeast strains for inclusion into biofertilizer for sustainable agriculture. PMID:25464336

  14. [Activated Sludge Bacteria Transforming Cyanopyridines and Amides of Pyridinecarboxylic Acids].

    PubMed

    Demakov, V A; Vasil'ev, D M; Maksimova, Yu G; Pavlova, Yu A; Ovechkina, G V; Maksimov, A Yu

    2015-01-01

    Species diversity of bacteria from the activated sludge of Perm biological waste treatment facilities capable of transformation of cyanopyridines and amides of pyridinecarboxylic acids was investigated. Enrichment cultures in mineral media with 3-cyanopyridine as the sole carbon and nitrogen source were used to obtain 32 clones of gram-negative heterotrophic bacteria exhibiting moderate growth on solid and liquid media with 3- and 4-cyanopyridine. Sequencing of the 16S rRNA gene fragments revealed that the clones with homology of at least 99% belonged to the genera Acinetobacte, Alcaligenes, Delftia, Ochrobactrum, Pseudomonas, Stenotrophomonas, and Xanthobacter. PCR analysis showed that 13 out of 32 isolates contained the sequences (-1070 bp) homologous to the nitrilase genes reported previously in Alcaligenes faecalis JM3 (GenBank, D13419.1). Nine clones were capable of nitrile and amide transformation in minimal salt medium. Acinetobacter sp. 11 h and Alcaligenes sp. osv transformed 3-cyanopyridine to nicotinamide, while most of the clones possessed amidase activity (0.5 to 46.3 mmol/(g h) for acetamide and 0.1 to 5.6 mmol/(g h) for nicotinamide). Nicotinamide utilization by strain A. faecalis 2 was shown to result in excretion of a secondary metabolite, which was identified as dodecyl acrylate at 91% probability. PMID:26263697

  15. Lactic Acid Bacteria Convert Human Fibroblasts to Multipotent Cells

    PubMed Central

    Ohta, Kunimasa; Kawano, Rie; Ito, Naofumi

    2012-01-01

    The human gastrointestinal tract is colonized by a vast community of symbionts and commensals. Lactic acid bacteria (LAB) form a group of related, low-GC-content, gram-positive bacteria that are considered to offer a number of probiotic benefits to general health. While the role of LAB in gastrointestinal microecology has been the subject of extensive study, little is known about how commensal prokaryotic organisms directly influence eukaryotic cells. Here, we demonstrate the generation of multipotential cells from adult human dermal fibroblast cells by incorporating LAB. LAB-incorporated cell clusters are similar to embryoid bodies derived from embryonic stem cells and can differentiate into endodermal, mesodermal, and ectodermal cells in vivo and in vitro. LAB-incorporated cell clusters express a set of genes associated with multipotency, and microarray analysis indicates a remarkable increase of NANOG, a multipotency marker, and a notable decrease in HOX gene expression in LAB-incorporated cells. During the cell culture, the LAB-incorporated cell clusters stop cell division and start to express early senescence markers without cell death. Thus, LAB-incorporated cell clusters have potentially wide-ranging implications for cell generation, reprogramming, and cell-based therapy. PMID:23300571

  16. Microbial Transformation of Dicarboxylic Acids by Airborne Bacteria

    NASA Astrophysics Data System (ADS)

    Cote, V.; Ariya, P.

    2004-05-01

    Organic aerosols are assumed to be key players in driving climatic changes and can cause health problems for human. Dicarboxylic acids (DCA) include a large fraction of identified important class of organic aerosols. In addition to direct sources, DCA are partly formed as the result of ozonolysis of terpenes and cyclic alkenes. Previous works in our laboratory show that airborne fungi collected from urban and suburban air play an important role in the transformation of severals organic aerosols such as DCA. Our present study focuses on understanding the potential chemical transformation induced by airborne bacteria and on identification of the transformation products. Airborne bacteria have been collected using a biosampler and cultivated on a solid media. Each bacterial colony is being tested by HPLC for their ability to transform DCA in liquid cultures. Also, GC-MS, SPME and NMR are being used to identify the metabolites generated from the transformation. We will present our preliminary results and we will discuss the application of bacterial activities on the chemical transformation of organics in atmosphere.

  17. [Biosynthesis of isocitric acid by the yeast yarrowia lipolytica and its regulation].

    PubMed

    Kamzolova, S V; Lunin, Y N; Allayarov, R K; Puntus, I F; Laptev, I A; Samojlenko, V A; Morgunov, I G

    2015-01-01

    We studied the biosynthesis of isocitric acid from rapeseed (canola) oil by the yeast Yarrowia lipolytica and its regulation. We determined a fundamental possibility for directed biosynthesis of isocitric acid by Y lipolytica yeast, with only minimal amounts of citric acid byproduct, when grown on a medium containing canola oil. Wild type strains of Y lipolytica were mutagenized by UV irradiation and treatment with N-methyl-N'-nitro-N-nitrosoguanidine (NG). Subsequent selection on media with acetate and isocitrate resulted in isolation of a UV/NG Y lipolytica UV/NG mutant that synthesized isocitrate and citrate at a ratio of 2.7:1. In the parent strain, this ratio is 1:1. Inhibition of isocitrate lyase, a key enzyme in the metabolism of isocitric acid, by the addition of itaconic acid resulted in increased synthesis of isocitrate with a ratio of isocitrate to citrate reaching 6:1. Culturing of the Y lipolytica UV/NG mutant in a pilot industrial fermenter in the presence of itaconic acid resulted in the production of 88.7 g/L of isocitric acid with a yield of 90%. PMID:26027362

  18. Variations in prebiotic oligosaccharide fermentation by intestinal lactic acid bacteria.

    PubMed

    Endo, Akihito; Nakamura, Saki; Konishi, Kenta; Nakagawa, Junichi; Tochio, Takumi

    2016-01-01

    Prebiotic oligosaccharides confer health benefits on the host by modulating the gut microbiota. Intestinal lactic acid bacteria (LAB) are potential targets of prebiotics; however, the metabolism of oligosaccharides by LAB has not been fully characterized. Here, we studied the metabolism of eight oligosaccharides by 19 strains of intestinal LAB. Among the eight oligosaccharides used, 1-kestose, lactosucrose and galactooligosaccharides (GOSs) led to the greatest increases in the numbers of the strains tested. However, mono- and disaccharides accounted for more than half of the GOSs used, and several strains only metabolized the mono- and di-saccharides in GOSs. End product profiles indicated that the amounts of lactate produced were generally consistent with the bacterial growth recorded. Oligosaccharide profiling revealed the interesting metabolic manner in Lactobacillus paracasei strains, which metabolized all oligosaccharides, but left sucrose when cultured with fructooligosaccharides. The present study clearly indicated that the prebiotic potential of each oligosaccharide differs. PMID:26888650

  19. Glycerol Ester Hydrolase Activity of Lactic Acid Bacteria

    PubMed Central

    Oterholm, Anders; Ordal, Z. John; Witter, Lloyd D.

    1968-01-01

    Seventeen strains of lactic acid bacteria were assayed for their glycerol ester hydrolase activity by using an improved agar-well technique, and eight strains by determining the activity in cell-free extracts using a pH-stat procedure. All cultures tested showed activity and hydrolyzed tributyrin more actively than they did tricaproin. The cell extract studies demonstrated that the cells contained intracellular esterases and lipases. The culture supernatant fluid was without activity. The lipase and the esterase differed in their relative activity to each other in the different extracts and in the ease by which they could be freed from the cellular debris. It is suggested that the lipase of these organisms is an endoenzyme and the esterase an ectoenzyme. PMID:5649866

  20. Lactic acid bacteria as adjuvants for sublingual allergy vaccines.

    PubMed

    Van Overtvelt, Laurence; Moussu, Helene; Horiot, Stéphane; Samson, Sandrine; Lombardi, Vincent; Mascarell, Laurent; van de Moer, Ariane; Bourdet-Sicard, Raphaëlle; Moingeon, Philippe

    2010-04-01

    We compared immunomodulatory properties of 11 strains of lactic acid bacteria as well as their capacity to enhance sublingual immunotherapy efficacy in a murine asthma model. Two types of bacterial strains were identified, including: (i) potent inducers of IL-12p70 and IL-10 in dendritic cells, supporting IFN-gamma and IL-10 production in CD4+ T cells such as Lactobacillus helveticus; (ii) pure Th1 inducers such as L. casei. Sublingual administration in ovalbumin-sensitized mice of L. helveticus, but not L. casei, reduced airways hyperresponsiveness, bronchial inflammation and proliferation of specific T cells in cervical lymph nodes. Thus, probiotics acting as a Th1/possibly Treg, but not Th1 adjuvant, potentiate tolerance induction via the sublingual route. PMID:20175969

  1. [Microevolution of lactic acid bacteria--A review].

    PubMed

    Song, Yuqin; Sun, Zhihong; Zhang, Heping

    2015-11-01

    Lactic acid bacteria (LAB) are important organisms in the food industry. The study of microevolution of LAB is helpful in understanding of the biological function and mechanism of these microbes. With the development of molecular biology, a large number of technical means have emerged, such as multilocus sequence typing ( MLST) and whole-genome re-sequencing, which enable the study of the phylogenetic and population evolution of LAB at genetic level. MLST has already been widely used on microevolution research of LAB to analyze the genetic diversity and population structure. Moreover, recently, as a result of the declining in sequencing cost, the advantage of whole genome sequencing technology is increasingly highlighted. This article elucidates the principle, methods and scientific significance of researching LAB microevolution, as well as introduces the application of whole genome sequencing in these aspects to provide new insights into further research. PMID:26915217

  2. Non-Mendelian Mutation Allowing Ureidosuccinic Acid Uptake in Yeast

    PubMed Central

    Lacroute, Francois

    1971-01-01

    Mutants of Saccharomyces cerevisiae capable of growth on a minimal medium supplemented with ureidosuccinic and glutamic acids have been isolated from a pyrimidineless strain. One of these mutants consistently yielded a non-Mendelian meiotic segregation. Moreover, the mitotic transmission of the mutation was very high. It is suggested that the mutation is nonchromosomal and could be mitochondrial. However, this mutation behaves very differently from other mitochondrial mutations. PMID:5573734

  3. A Plasma Membrane Association Module in Yeast Amino Acid Transporters.

    PubMed

    Popov-Čeleketić, Dušan; Bianchi, Frans; Ruiz, Stephanie J; Meutiawati, Febrina; Poolman, Bert

    2016-07-29

    Amino acid permeases (AAPs) in the plasma membrane (PM) of Saccharomyces cerevisiae are responsible for the uptake of amino acids and involved in regulation of their cellular levels. Here, we report on a strong and complex module for PM association found in the C-terminal tail of AAPs. Using in silico analyses and mutational studies we found that the C-terminal sequences of Gap1, Bap2, Hip1, Tat1, Tat2, Mmp1, Sam3, Agp1, and Gnp1 are about 50 residues long, associate with the PM, and have features that discriminate them from the termini of organellar amino acid transporters. We show that this sequence (named PMasseq) contains an amphipathic α-helix and the FWC signature, which is palmitoylated by palmitoyltransferase Pfa4. Variations of PMasseq, found in different AAPs, lead to different mobilities and localization patterns, whereas the disruption of the sequence has an adverse effect on cell viability. We propose that PMasseq modulates the function and localization of AAPs along the PM. PMasseq is one of the most complex protein signals for plasma membrane association across species and can be used as a delivery vehicle for the PM. PMID:27226538

  4. Prevalence and impact of single-strain starter cultures of lactic acid bacteria on metabolite formation in sourdough.

    PubMed

    Ravyts, Frédéric; De Vuyst, Luc

    2011-09-01

    Flavour of type II sourdoughs is influenced by the ingredients, processing conditions, and starter culture composition. It is, however, not fully clear to what extent different sourdough lactic acid bacteria (LAB) contribute to flavour. Therefore, two types of flour (rye and wheat) and different LAB starter culture strains were used to prepare sourdoughs, thereby leaving the yeast microbiota uncontrolled. All LAB starter culture strains tested were shown to be prevalent and to acidify the flour/water mixture to pH values between 3.1 and 3.9 after 24h of fermentation. Multiple aldehydes, alcohols, ketones, and carboxylic acids were produced by the sourdough-associated microbiota throughout the fermentation period. Based on the organoleptic evaluation of breads produced with these sourdoughs, five LAB strains were selected to perform prolonged wheat and rye fermentations as to their capacity to result in an acidic (Lactobacillus fermentum IMDO 130101, Lactobacillus plantarum IMDO 130201, and Lactobacillus crustorum LMG 23699), buttermilk-like (Lactobacillus amylovorus DCE 471), or fruity flavour (Lactobacillus sakei CG1). Upon prolonged fermentation, higher metabolite concentrations were produced. For instance, L. sakei CG1 produced the highest amounts of 3-methyl-1-butanol, which was further converted into 3-methylbutyl acetate. The latter compound resulted in a fruity banana flavour after 48h of fermentation, probably due to yeast interference. Rye fermentations resulted in sourdoughs richer in volatiles than wheat, including 3-methyl-1-butanol, 2-phenylethanol, and ethyl acetate. PMID:21645811

  5. Phenolic acid degradation potential and growth behavior of lactic acid bacteria in sunflower substrates.

    PubMed

    Fritsch, Caroline; Heinrich, Veronika; Vogel, Rudi F; Toelstede, Simone

    2016-08-01

    Sunflower flour provides a high content of protein with a well-balanced amino acid composition and is therefore regarded as an attractive source for protein. The use for human nutrition is hindered by phenolic compounds, mainly chlorogenic acid, which can lead under specific circumstances to undesirable discolorations. In this study, growth behavior and degradation ability of chlorogenic acid of four lactic acid bacteria were explored. Data suggested that significant higher fermentation performances on sunflower flour as compared to sunflower protein concentrate were reached by Lactobacillus plantarum, Pediococcus pentosaceus, Lactobacillus gasseri and Bifidobacterium animalis subsp. lactis. In fermentation with the latter two strains reduced amounts of chlorogenic acid were observed in sunflower flour (-11.4% and -19.8%, respectively), which were more pronounced in the protein concentrate (-50.7% and -95.6%, respectively). High tolerances against chlorogenic acid and the cleavage product quinic acid with a minimum inhibitory concentration (MIC) of ≥20.48 mg/ml after 48 h were recorded for all strains except Bifidobacterium animalis subsp. lactis, which was more sensitive. The second cleavage compound, caffeic acid revealed a higher antimicrobial potential with MIC values of 0.64-5.12 mg/ml. In this proof of concept study, degradation versus inhibitory effect suggest the existence of basic mechanisms of interaction between phenolic acids in sunflower and lactic acid bacteria and a feasible way to reduce the chlorogenic acid content, which may help to avoid undesired color changes. PMID:27052717

  6. Production of fatty acid-derived oleochemicals and biofuels by synthetic yeast cell factories

    PubMed Central

    Zhou, Yongjin J.; Buijs, Nicolaas A.; Zhu, Zhiwei; Qin, Jiufu; Siewers, Verena; Nielsen, Jens

    2016-01-01

    Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level production of free fatty acids (FFAs) in a yeast cell factory, and the production of alkanes and fatty alcohols from its descendants. The engineered strain produces up to 10.4 g l−1 of FFAs, which is the highest reported titre to date. Furthermore, through screening of specific pathway enzymes, endogenous alcohol dehydrogenases and aldehyde reductases, we reconstruct efficient pathways for conversion of fatty acids to alkanes (0.8 mg l−1) and fatty alcohols (1.5 g l−1), to our knowledge the highest titres reported in S. cerevisiae. This should facilitate the construction of yeast cell factories for production of fatty acids derived products and even aldehyde-derived chemicals of high value. PMID:27222209

  7. Production of fatty acid-derived oleochemicals and biofuels by synthetic yeast cell factories.

    PubMed

    Zhou, Yongjin J; Buijs, Nicolaas A; Zhu, Zhiwei; Qin, Jiufu; Siewers, Verena; Nielsen, Jens

    2016-01-01

    Sustainable production of oleochemicals requires establishment of cell factory platform strains. The yeast Saccharomyces cerevisiae is an attractive cell factory as new strains can be rapidly implemented into existing infrastructures such as bioethanol production plants. Here we show high-level production of free fatty acids (FFAs) in a yeast cell factory, and the production of alkanes and fatty alcohols from its descendants. The engineered strain produces up to 10.4 g l(-1) of FFAs, which is the highest reported titre to date. Furthermore, through screening of specific pathway enzymes, endogenous alcohol dehydrogenases and aldehyde reductases, we reconstruct efficient pathways for conversion of fatty acids to alkanes (0.8 mg l(-1)) and fatty alcohols (1.5 g l(-1)), to our knowledge the highest titres reported in S. cerevisiae. This should facilitate the construction of yeast cell factories for production of fatty acids derived products and even aldehyde-derived chemicals of high value. PMID:27222209

  8. Field assessment of yeast- and oxalic Acid-generated carbon dioxide for mosquito surveillance.

    PubMed

    Harwood, James F; Richardson, Alec G; Wright, Jennifer A; Obenauer, Peter J

    2014-12-01

    Carbon dioxide (CO2) sources improve the efficacy of mosquito traps. However, traditional CO2 sources (dry ice or compressed gas) may be difficult to acquire for vector surveillance during military contingency operations. For this reason, a new and convenient source of CO2 is required. Two novel CO2 generators were evaluated in order to address this capability gap: 1) an electrolyzer that converts solid oxalic acid into CO2 gas, and 2) CO2 produced by yeast as it metabolizes sugar. The flow rate and CO2 concentration produced by each generator were measured, and each generator's ability to attract mosquitoes to BG-Sentinel™ traps during day surveillance and to Centers for Disease Control and Prevention light traps with incandescent bulbs during night surveillance was compared to dry ice and compressed gas in Jacksonville, FL. The electrolyzed oxalic acid only slightly increased the number of mosquitoes captured compared to unbaited traps. Based on the modest increase in mosquito collection for traps paired with the oxalic acid, it is not a suitable stand-in for either of the 2 traditional CO2 sources. Conversely, the yeast-generated CO2 resulted in collections with mosquito abundance and species richness more closely resembling those of the traditional CO2 sources, despite achieving a lower CO2 flow rate. Therefore, if dry ice or compressed gas cannot be acquired for vector surveillance, yeast-generated CO2 can significantly improve trap capability. PMID:25843133

  9. A comparative study on glycerol metabolism to erythritol and citric acid in Yarrowia lipolytica yeast cells.

    PubMed

    Tomaszewska, Ludwika; Rakicka, Magdalena; Rymowicz, Waldemar; Rywińska, Anita

    2014-09-01

    Citric acid and erythritol biosynthesis from pure and crude glycerol by three acetate-negative mutants of Yarrowia lipolytica yeast was investigated in batch cultures in a wide pH range (3.0-6.5). Citric acid biosynthesis was the most effective at pH 5.0-5.5 in the case of Wratislavia 1.31 and Wratislavia AWG7. With a decreasing pH value, the direction of biosynthesis changed into erythritol synthesis accompanied by low production of citric acid. Pathways of glycerol conversion into erythritol and citric acid were investigated in Wratislavia K1 cells. Enzymatic activity was compared in cultures run at pH 3.0 and 4.5, that is, under conditions promoting the production of erythritol and citric acid, respectively. The effect of pH value (3.0 and 4.5) and NaCl presence on the extracellular production and intracellular accumulation of citric acid and erythritol was compared as well. Low pH and NaCl resulted in diminished activity of glycerol kinase, whereas such conditions stimulated the activity of glycerol-3-phosphate dehydrogenase. The presence of NaCl strongly influenced enzymes activity - the effective erythritol production was correlated with a high activity of transketolase and erythrose reductase. Therefore, presented results confirmed that transketolase and erythrose reductase are involved in the overproduction of erythritol in the cells of Y. lipolytica yeast. PMID:25041612

  10. Precursor directed biosynthesis of odd-numbered fatty acids by different yeasts.

    PubMed

    Řezanka, Tomáš; Kolouchová, Irena; Sigler, Karel

    2015-09-01

    Precursor-directed biosynthesis was used for directed preparation of positional isomers of heptadecanoic acid (17:1), which have convenient pharmacological properties. Cultivation of Candida sp., Kluyveromyces polysporus, Rhodotorula glutinis, Saccharomyces cerevisiae, Torulaspora delbrueckii, Trichosporon cutaneum, and Yarrowia lipolytica on 20 g/L glucose, 4 g/L acetic, or 4 g/L propionic acids yielded different proportions of 17:1. Cultivation on carbon sources with even numbers of carbon atoms (glucose and acetic acid) produced preferentially 8Z- and 10Z-heptadecenoic acids in about equal amounts, in agreement with the proposed biosynthesis of fatty acids, whereas cultivation on propionic acid as the only carbon source produced over 90 % of total fatty acids of 9-17:1 out of all possible positional isomers. The structures of positional isomers of 17:1 acid were determined using dimethyl disulfides of fatty acid methyl esters. In cultivation of Candida sp. on propionic acid, the yield of heptadecenoic acid reached 111 mg/L cultivation medium. Principal component analysis was used for identifying the effect of cultivation conditions on the production of the 17:1 acid by individual yeast strains. PMID:25813199

  11. Diversity of the lactic acid bacterium and yeast microbiota in the switch from firm- to liquid-sourdough fermentation.

    PubMed

    Di Cagno, Raffaella; Pontonio, Erica; Buchin, Solange; De Angelis, Maria; Lattanzi, Anna; Valerio, Francesca; Gobbetti, Marco; Calasso, Maria

    2014-05-01

    Four traditional type I sourdoughs were comparatively propagated (28 days) under firm (dough yield, 160) and liquid (dough yield, 280) conditions to mimic the alternative technology options frequently used for making baked goods. After 28 days of propagation, liquid sourdoughs had the lowest pH and total titratable acidity (TTA), the lowest concentrations of lactic and acetic acids and free amino acids, and the most stable density of presumptive lactic acid bacteria. The cell density of yeasts was the highest in liquid sourdoughs. Liquid sourdoughs showed simplified microbial diversity and harbored a low number of strains, which were persistent. Lactobacillus plantarum dominated firm sourdoughs over time. Leuconostoc lactis and Lactobacillus brevis dominated only some firm sourdoughs, and Lactobacillus sanfranciscensis persisted for some time only in some firm sourdoughs. Leuconostoc citreum persisted in all firm and liquid sourdoughs, and it was the only species detected in liquid sourdoughs at all times; it was flanked by Leuconostoc mesenteroides in some sourdoughs. Saccharomyces cerevisiae, Candida humilis, Saccharomyces servazzii, Saccharomyces bayanus-Kazachstania sp., and Torulaspora delbrueckii were variously identified in firm and liquid sourdoughs. A total of 197 volatile components were identified through purge and trap-/solid-phase microextraction-gas chromatography-mass spectrometry (PT-/SPME-GC-MS). Aldehydes, several alcohols, and some esters were at the highest levels in liquid sourdoughs. Firm sourdoughs mainly contained ethyl acetate, acetic acid, some sulfur compounds, and terpenes. The use of liquid fermentation would change the main microbial and biochemical features of traditional baked goods, which have been manufactured under firm conditions for a long time. PMID:24632249

  12. Diversity of the Lactic Acid Bacterium and Yeast Microbiota in the Switch from Firm- to Liquid-Sourdough Fermentation

    PubMed Central

    Di Cagno, Raffaella; Pontonio, Erica; Buchin, Solange; De Angelis, Maria; Lattanzi, Anna; Valerio, Francesca; Calasso, Maria

    2014-01-01

    Four traditional type I sourdoughs were comparatively propagated (28 days) under firm (dough yield, 160) and liquid (dough yield, 280) conditions to mimic the alternative technology options frequently used for making baked goods. After 28 days of propagation, liquid sourdoughs had the lowest pH and total titratable acidity (TTA), the lowest concentrations of lactic and acetic acids and free amino acids, and the most stable density of presumptive lactic acid bacteria. The cell density of yeasts was the highest in liquid sourdoughs. Liquid sourdoughs showed simplified microbial diversity and harbored a low number of strains, which were persistent. Lactobacillus plantarum dominated firm sourdoughs over time. Leuconostoc lactis and Lactobacillus brevis dominated only some firm sourdoughs, and Lactobacillus sanfranciscensis persisted for some time only in some firm sourdoughs. Leuconostoc citreum persisted in all firm and liquid sourdoughs, and it was the only species detected in liquid sourdoughs at all times; it was flanked by Leuconostoc mesenteroides in some sourdoughs. Saccharomyces cerevisiae, Candida humilis, Saccharomyces servazzii, Saccharomyces bayanus-Kazachstania sp., and Torulaspora delbrueckii were variously identified in firm and liquid sourdoughs. A total of 197 volatile components were identified through purge and trap–/solid-phase microextraction–gas chromatography-mass spectrometry (PT–/SPME–GC-MS). Aldehydes, several alcohols, and some esters were at the highest levels in liquid sourdoughs. Firm sourdoughs mainly contained ethyl acetate, acetic acid, some sulfur compounds, and terpenes. The use of liquid fermentation would change the main microbial and biochemical features of traditional baked goods, which have been manufactured under firm conditions for a long time. PMID:24632249

  13. Cell cycle control in bacteria and yeast: a case of convergent evolution?

    PubMed

    Brazhnik, Paul; Tyson, John J

    2006-03-01

    Superficially similar traits in phylogenetically unrelated species often result from adaptation to common selection pressures. Examples of convergent evolution are known at the levels of whole organisms, organ systems, gene networks and specific proteins. The phenotypic properties of living things, on the other hand, are determined in large part by complex networks of interacting proteins. Here we present a mathematical model of the network of proteins that controls DNA synthesis and cell division in the alpha-proteobacterium, Caulobacter crescentus. By comparing the protein regulatory circuits for cell reproduction in Caulobacter with that in budding yeast (Saccharomyces cerevisiae), we suggest that convergent evolution may have created similar molecular reaction networks in order to accomplish the same purpose of coordinating DNA synthesis to cell division. Although the genes and proteins involved in cell cycle regulation in prokaryotes and eukaryotes are very different and (apparently) phylogenetically unrelated, they seem to be wired together in similar regulatory networks, which coordinate cell cycle events by identical dynamical principles. PMID:16552176

  14. Pristine environments harbor a new group of oligotrophic 2,4-dichlorophenoxyacetic acid-degrading bacteria.

    PubMed Central

    Kamagata, Y; Fulthorpe, R R; Tamura, K; Takami, H; Forney, L J; Tiedje, J M

    1997-01-01

    2,4-Dichlorophenoxyacetic acid (2,4-D)-degrading bacteria were isolated from pristine environments which had no history of 2,4-D exposure. By using 2,4-D dye indicator medium or 14C-labeled 2,4-D medium, six strains were isolated from eight enrichment cultures capable of degrading 2,4-D. Phylogenetic analyses based on 16S ribosomal DNA (rDNA) sequencing and physiological properties revealed that one isolate from Hawaiian volcanic soil could be classified in the genus Variovorax (a member of the beta subdivision of the class Proteobacteria) and that the other five isolates from Hawaiian volcanic soils, Saskatchewan forest soil, and Chilean forest soil have 16S rDNAs with high degrees of similarity to those of the Bradyrhizobium group (a member of the alpha subdivision of the class Proteobacteria). All the isolates grow slowly on either nutrient media (0.1 x Bacto Peptone-tryptone-yeast extract-glucose [PTYG] or 0.1 x Luria broth [LB] medium) or 2,4-D medium, with mean generation times of 16 to 30 h, which are significantly slower than previously known 2,4-D degraders. Nutrient-rich media such as full-strength PTYG and LB medium did not allow their growth. PCR amplification using internal consensus sequences of tfdA (a gene encoding an enzyme for the first step of 2,4-D mineralization, found in pJP4 of Alcaligenes eutrophus JMP134 and some other 2,4-D-degrading bacteria) as primers and Southern hybridization with pJP4-tfdA as a probe revealed that the isolate belonging to the genus Variovorax carried the tfdA gene. This gene was transmissible to A. eutrophus JMP228 carrying a plasmid with a mutant tfdA gene. The other five isolates did not appear to carry tfdA, and 2,4-D-specific alpha-ketoglutarate-dependent dioxygenase activity could not be detected in cell lysates. These results indicate that 2,4-D-degrading bacteria in pristine environments are slow-growing bacteria and that most of their phylogenies and catabolic genes differ from those of 2,4-D degraders

  15. Selection of lactic acid bacteria isolated from Tunisian cereals and exploitation of the use as starters for sourdough fermentation.

    PubMed

    Mamhoud, Asma; Nionelli, Luana; Bouzaine, Taroub; Hamdi, Moktar; Gobbetti, Marco; Rizzello, Carlo Giuseppe

    2016-05-16

    Wheat bread is the most popular staple food consumed in Tunisia and, despite the niche production of some typical breads (e.g. Tabouna, Mlawi, Mtabga), the major part is currently produced with baker's yeast at industrial or, mainly, at artisanal level, while the use of sourdough fermentation is rarely reported. Considering the growing national demand for cereal baked goods, it can be hypothesized that sourdough fermentation through the use of selected lactic acid bacteria as starters could improve the overall quality and the diversification of local products. Different cereal grains were collected from the regions of Ariana, Bizerta, Beja Nabeul, and Seliana, and the autochthonous lactic acid bacteria were isolated, identified, characterized and selected on the basis of the kinetics of acidification, the proteolytic activity, and the quotient of fermentation. Lactobacillus curvatus MA2, Pediococcus pentosaceus OA2, and Pediococcus acidilactici O1A1 were used together as mixed starter to obtain a selected sourdough. According to the backslopping procedure, a type I sourdough was made from a Tunisian flour (spontaneous sourdough). Compared to the use of the spontaneous sourdough, the one obtained with selected and mixed starters by a unique fermentation step, favored the increase of the concentrations of organic acids, phenols, and total free amino acids, the most suitable quotient of fermentation, and the most intense phytase and antioxidant activities, that increased ca. 20% compared to the control. Moreover, the selected starters improved the in vitro protein digestibility (ca. 82% when selected sourdough was used), textural and sensory features of the breads, as determined by textural profile analysis and panel test, respectively. This study aimed at exploiting the potential of selected autochthonous lactic acid bacteria and extending the use of a sourdough (type II), thanks to the set-up of a two-step fermentation protocol designed for application at the

  16. Myosin-cross-reactive antigens from four different lactic acid bacteria are fatty acid hydratases.

    PubMed

    Yang, Bo; Chen, Haiqin; Song, Yuanda; Chen, Yong Q; Zhang, Hao; Chen, Wei

    2013-01-01

    The 67 kDa myosin-cross-reactive antigen (MCRA) is a member of the MCRA family of proteins present in a wide range of bacteria and was predicted to have fatty acid isomerase function. We have now characterised the catalytic activity of MCRAs from four LAB stains, including Lactobacillus rhamnosus LGG, L. plantarum ST-III, L. acidophilus NCFM and Bifidobacterium animalis subsp. lactis BB-12. MCRA genes from these strains were cloned and expressed in Escherichia coli, and the recombinant protein function was analysed with lipid profiles by GC-MS. The four MCRAs catalysed the conversion of linoleic acid and oleic acid to their respective 10-hydroxy derivatives, which suggests that MCRA proteins catalyse the first step in conjugated linoleic acid production. This is the first report of MCRA from L. rhamnosus with such catalytic function. PMID:22955678

  17. Methane emissions from beef cattle: Effects of monensin, sunflower oil, enzymes, yeast, and fumaric acid.

    PubMed

    McGinn, S M; Beauchemin, K A; Coates, T; Colombatto, D

    2004-11-01

    Methane emitted from the livestock sector contributes to greenhouse gas (GHG) emissions. Understanding the effects of diet on enteric methane production can help refine GHG emission inventories and identify viable GHG reduction strategies. Our study focused on measuring methane and carbon dioxide emissions, total-tract digestibility, and ruminal fermentation in growing beef cattle fed a diet supplemented with various additives or ingredients. Two experiments, each designed as a 4 x 4 Latin square with 21-d periods, were conducted using 16 Holstein steers (initial BW 311.6 +/- 12.3 kg). In Exp. 1, treatments were control (no additive), monensin (Rumensin, Elanco Animal Health, Indianapolis, IN; 33 mg/kg DM), sunflower oil (400 g/d, approximately 5% of DMI), and proteolytic enzyme (Protex 6-L, Genencor Int., Inc., CA; 1 mL/kg DM). In Exp. 2, treatments were control (no additive), Procreatin-7 yeast (Prince Agri Products, Inc., Quincy, IL; 4 g/d), Levucell SC yeast (Lallemand, Inc., Rexdale, Ontario, Canada; 1 g/d), and fumaric acid (Bartek Ingredients Inc., Stoney Creek, Ontario, Canada; 80 g/d). The basal diet consisted of 75% barley silage, 19% steam-rolled barley grain, and 6% supplement (DM basis). Four large chambers (two animals per chamber) were equipped with lasers and infrared gas analyzers to measure methane and carbon dioxide, respectively, for 3 d each period. Total-tract digestibility was determined using chromic oxide. Approximately 6.5% of the GE consumed was lost in the form of methane emissions from animals fed the control diet. In Exp. 1, sunflower oil decreased methane emissions by 22% (P = 0.001) compared with the control, whereas monensin (P = 0.44) and enzyme had no effect (P = 0.82). However, oil decreased (P = 0.03) the total-tract digestibility of NDF by 20%. When CH(4) emissions were corrected for differences in energy intake, the loss of GE to methane was decreased by 21% (P = 0.002) using oil and by 9% (P = 0.09) using monensin. In Exp. 2

  18. Factors affecting acetic acid production by yeasts in strongly clarified grape musts.

    PubMed

    Moruno, E G; Delfini, C; Pessione, E; Giunta, C

    1993-01-01

    High acetate content in a wine, after strong clarification of the must, is due to depletion in the yeast cells of important metabolites (normally present in non-clarified musts) such as metals, amino acids, polyphenolic compounds and unsaturated fatty acids. These substances were added separately to a synthetic medium, comparable in composition to the clarified must, which was then inoculated with a high acetate producer strain. No effects were observed after the addition of various metals and amino acids. The addition of unsaturated fatty acids (Tween 80) caused a significant (p = 0.01) decrease in acetate content. Similar results have been obtained in the presence of polyphenols (catechins and anthocyans): their mechanism of action is probably due to direct inhibition of the enzyme aldehyde dehydrogenase. Control experiments were performed with a low acetate producer strain, and a reduction in acetate content was detected. No differences in the glyceropyruvic metabolism of the two strains was evident. PMID:8366831

  19. Solid and liquid media for isolating and cultivating acidophilic and acid-tolerant sulfate-reducing bacteria.

    PubMed

    Ňancucheo, Ivan; Rowe, Owen F; Hedrich, Sabrina; Johnson, D Barrie

    2016-05-01

    Growth media have been developed to facilitate the enrichment and isolation of acidophilic and acid-tolerant sulfate-reducing bacteria (aSRB) from environmental and industrial samples, and to allow their cultivation in vitro The main features of the 'standard' solid and liquid devised media are as follows: (i) use of glycerol rather than an aliphatic acid as electron donor; (ii) inclusion of stoichiometric concentrations of zinc ions to both buffer pH and to convert potentially harmful hydrogen sulphide produced by the aSRB to insoluble zinc sulphide; (iii) inclusion of Acidocella aromatica (an heterotrophic acidophile that does not metabolize glycerol or yeast extract) in the gel underlayer of double layered (overlay) solid media, to remove acetic acid produced by aSRB that incompletely oxidize glycerol and also aliphatic acids (mostly pyruvic) released by acid hydrolysis of the gelling agent used (agarose). Colonies of aSRB are readily distinguished from those of other anaerobes due to their deposition and accumulation of metal sulphide precipitates. Data presented illustrate the effectiveness of the overlay solid media described for isolating aSRB from acidic anaerobic sediments and low pH sulfidogenic bioreactors. PMID:27036143

  20. Comparison of D-gluconic acid production in selected strains of acetic acid bacteria.

    PubMed

    Sainz, F; Navarro, D; Mateo, E; Torija, M J; Mas, A

    2016-04-01

    The oxidative metabolism of acetic acid bacteria (AAB) can be exploited for the production of several compounds, including D-gluconic acid. The production of D-gluconic acid in fermented beverages could be useful for the development of new products without glucose. In the present study, we analyzed nineteen strains belonging to eight different species of AAB to select those that could produce D-gluconic acid from D-glucose without consuming D-fructose. We tested their performance in three different media and analyzed the changes in the levels of D-glucose, D-fructose, D-gluconic acid and the derived gluconates. D-Glucose and D-fructose consumption and D-gluconic acid production were heavily dependent on the strain and the media. The most suitable strains for our purpose were Gluconobacter japonicus CECT 8443 and Gluconobacter oxydans Po5. The strawberry isolate Acetobacter malorum (CECT 7749) also produced D-gluconic acid; however, it further oxidized D-gluconic acid to keto-D-gluconates. PMID:26848948

  1. Bacteria and yeast associated with sugar beet root rot at harvest in the Intermountain West

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An undescribed bacterial-like root rot has been observed in sugar beets at harvest time in the Intermountain West. This root rot was observed during surveys of recently harvested sugar beets in 2004 and 2005. Microorganisms recovered from 287 roots fell into the following groups: lactic acid bacte...

  2. Effect of Algae and Plant Lectins on Planktonic Growth and Biofilm Formation in Clinically Relevant Bacteria and Yeasts

    PubMed Central

    Vasconcelos, Mayron Alves; Arruda, Francisco Vassiliepe Sousa; Carneiro, Victor Alves; Silva, Helton Colares; Nascimento, Kyria Santiago; Sampaio, Alexandre Holanda; Cavada, Benildo; Teixeira, Edson Holanda; Henriques, Mariana

    2014-01-01

    This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250 μg/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins. PMID:24982871

  3. Distribution of bacteria and yeasts within the 10-ml Isolator during the processing of seeded blood samples.

    PubMed

    Kellogg, J A; Levisky, J S

    1986-02-01

    Forty-five organisms consisting of stock cultures and clinical isolates of bacteria and yeast were separately inoculated into outdated blood bank blood to achieve a concentration of approximately 100 CFU/ml. Blood with each organism was introduced into groups of four Isolators (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.), which were then processed according to the Isostat instructions of the manufacturer. The supernatant, sediment, and wash (material removed from the surface of the slanted stopper after sediment removal) were inoculated onto 5% sheep blood agar plates. Cultures were incubated aerobically (5 to 10% CO2) at 35 degrees C for 48 to 72 h. From the 180 Isolators, the mean recovery was 6% (range, 0 to 48%) for the supernatant, 87% (range, 47 to 98%) for the sediment, and 8% (range, 3 to 23%) for the wash. Neither variation among technologists nor intentional misalignment of additional Isolators in the centrifuge could explain all of the losses of microorganisms from the sediment. The manual nature of the Isolator procedure, which led to the loss of significant amounts of organisms from the sediment, may help to explain false-negative Isolator results obtained from blood of patients, particularly when small numbers of pathogens are present. PMID:3084546

  4. Effect of algae and plant lectins on planktonic growth and biofilm formation in clinically relevant bacteria and yeasts.

    PubMed

    Vasconcelos, Mayron Alves; Arruda, Francisco Vassiliepe Sousa; Carneiro, Victor Alves; Silva, Helton Colares; Nascimento, Kyria Santiago; Sampaio, Alexandre Holanda; Cavada, Benildo; Teixeira, Edson Holanda; Henriques, Mariana; Pereira, Maria Olivia

    2014-01-01

    This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250  μ g/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins. PMID:24982871

  5. Animal Rennets as Sources of Dairy Lactic Acid Bacteria

    PubMed Central

    Cruciata, Margherita; Sannino, Ciro; Ercolini, Danilo; Scatassa, Maria L.; De Filippis, Francesca; Mancuso, Isabella; La Storia, Antonietta; Moschetti, Giancarlo

    2014-01-01

    The microbial composition of artisan and industrial animal rennet pastes was studied by using both culture-dependent and -independent approaches. Pyrosequencing targeting the 16S rRNA gene allowed to identify 361 operational taxonomic units (OTUs) to the genus/species level. Among lactic acid bacteria (LAB), Streptococcus thermophilus and some lactobacilli, mainly Lactobacillus crispatus and Lactobacillus reuteri, were the most abundant species, with differences among the samples. Twelve groups of microorganisms were targeted by viable plate counts revealing a dominance of mesophilic cocci. All rennets were able to acidify ultrahigh-temperature-processed (UHT) milk as shown by pH and total titratable acidity (TTA). Presumptive LAB isolated at the highest dilutions of acidified milks were phenotypically characterized, grouped, differentiated at the strain level by randomly amplified polymorphic DNA (RAPD)-PCR analysis, and subjected to 16S rRNA gene sequencing. Only 18 strains were clearly identified at the species level, as Enterococcus casseliflavus, Enterococcus faecium, Enterococcus faecalis, Enterococcus lactis, Lactobacillus delbrueckii, and Streptococcus thermophilus, while the other strains, all belonging to the genus Enterococcus, could not be allotted into any previously described species. The phylogenetic analysis showed that these strains might represent different unknown species. All strains were evaluated for their dairy technological performances. All isolates produced diacetyl, and 10 of them produced a rapid pH drop in milk, but only 3 isolates were also autolytic. This work showed that animal rennet pastes can be sources of LAB, mainly enterococci, that might contribute to the microbial diversity associated with dairy productions. PMID:24441167

  6. Activity of capryloyl collagenic acid against bacteria involved in acne.

    PubMed

    Fourniat, J; Bourlioux, P

    1989-12-01

    Synopsis Capryloyl collagenic acid (Lipacide C8Co) has similar bacteriostatic activity in vitro to that of benzoyl peroxide towards the bacteria found in acne lesions (Staphylococcus aureus, Staphylococcus epidermidis and Propionibacterium acnes) (MIC between 1 and 4 mg ml(-1) for C8Co, and between 0.5 and 5 mg ml(-1) for benzoyl peroxide). The presence of Emulgine M8 did not affect the bacteriostatic activity of C8Co. A 4% w/v solution of C8Co (incorporating Emulgine M8) fulfilled the criteria for an antiseptic preparation as laid down by the French Pharmacopoeia (10th Edition), and had a spectrum 5 bactericidal activity according to the French Standard AFNOR NF T 72-151. The excellent cutaneous tolerance of capryloyl collagenic acid would indicate that an aqueous solution might be of value for topical treatment of the bacterial component of acne. Résumé Activité antibactérienne de l'acide capryloyl-collagénique vis à vis des bactéries impliquées dans l'etiologie de l'acné L'acide capryloyl-collagénique (Lipacide C8Co) et le peroxyde de benzoyle présentent une activité bactériostatique in-vitroéquivalente vis à vis des espèces bactériennes retrouvées au niveau des lésions acnéiques (Staphylococcus aureus, S. epidermidis et Propionibacterium acnes) (CMI comprise entre 1 et 4 mg ml(-1) pour le lipoaminoacide, et 0,5 et 5 mg ml(-1) pour le peroxyde de benzoyle). La mise en solution aqueuse de l'acide capryloyl-collagénique en présence d'Emulgine M8 ne modifie pas son activité bactériostatique. Une telle solution, à 4% m/V d'acide capryloyl-collagénique et 5% m/V d'Emulgine M8, satisfait à l'essai d'activité des préparations antiseptiques décrit à la Pharmacopée Française (Xème Ed.) (concentration minimale antiseptique: 10% v/V, pour un temps de contact de 5 min à 32 degrees C entre les germes tests et la solution diluée en eau distillée), et posséde une activité bactéricide antiseptique spectre 5 conforme à la norme AFNOR NF T

  7. Screening of Immune-Active Lactic Acid Bacteria

    PubMed Central

    Hwang, E-Nam; Kang, Sang-Mo; Kim, Mi-Jung

    2015-01-01

    The purpose of this study was to investigate the effect of lactic acid bacteria (LAB) cell wall extract on the proliferation and cytokine production of immune cells to select suitable probiotics for space food. Ten strains of LAB (Lactobacillus bulgaricus, L. paracasei, L. casei, L. acidophilus, L. plantarum, L. delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pedicoccus pentosaceus) were sub-cultured and further cultured for 3 d to reach 7-10 Log colony-forming units (CFU)/mL prior to cell wall extractions. All LAB cell wall extracts failed to inhibit the proliferation of BALB/c mouse splenocytes or mesenteric lymphocytes. Most LAB cell wall extracts except those of L. plantarum and L. delbrueckii induced the proliferation of both immune cells at tested concentrations. In addition, the production of TH1 cytokine (IFN-γ) rather than that of TH2 cytokine (IL-4) was enhanced by LAB cell wall extracts. Of ten LAB extracts, four (from L. acidophilus, L. bulgaricus, L. casei, and S. thermophiles) promoted both cell proliferating and TH1 cytokine production. These results suggested that these LAB could be used as probiotics to maintain immunity and homeostasis for astronauts in extreme space environment and for general people in normal life. PMID:26761877

  8. Co-culture-inducible bacteriocin production in lactic acid bacteria.

    PubMed

    Chanos, Panagiotis; Mygind, Tina

    2016-05-01

    It is common knowledge that microorganisms have capabilities, like the production of antimicrobial compounds, which do not normally appear in ideal laboratory conditions. Common antimicrobial discovery techniques require the isolation of monocultures and their individual screening against target microorganisms. One strategy to achieve expression of otherwise hidden antimicrobials is induction by co-cultures. In the area of bacteriocin-producing lactic acid bacteria, there has been some research focusing into the characteristics of co-culture-inducible bacteriocin production and particularly the molecular mechanism(s) of such interactions. No clear relationship has been seen between bacteriocin-inducing and bacteriocin-producing microorganisms. The three-component regulatory system seems to be playing a central role in the induction, but inducing compounds have not been identified or characterized. However, the presence of the universal messenger molecule autoinducer-2 has been associated in some cases with the co-culture-inducible bacteriocin phenotype and it may play the role in the additional regulation of the three-component regulatory system. Understanding the mechanisms of induction would facilitate the development of strategies for screening and development of co-culture bacteriocin-producing systems and novel products as well as the perseverance of such systems in food and down to the intestinal tract, possibly conferring a probiotic effect on the host. PMID:27037694

  9. Screening of Immune-Active Lactic Acid Bacteria.

    PubMed

    Hwang, E-Nam; Kang, Sang-Mo; Kim, Mi-Jung; Lee, Ju-Woon

    2015-01-01

    The purpose of this study was to investigate the effect of lactic acid bacteria (LAB) cell wall extract on the proliferation and cytokine production of immune cells to select suitable probiotics for space food. Ten strains of LAB (Lactobacillus bulgaricus, L. paracasei, L. casei, L. acidophilus, L. plantarum, L. delbruekii, Lactococcus lactis, Streptococcus thermophilus, Bifidobacterium breve, and Pedicoccus pentosaceus) were sub-cultured and further cultured for 3 d to reach 7-10 Log colony-forming units (CFU)/mL prior to cell wall extractions. All LAB cell wall extracts failed to inhibit the proliferation of BALB/c mouse splenocytes or mesenteric lymphocytes. Most LAB cell wall extracts except those of L. plantarum and L. delbrueckii induced the proliferation of both immune cells at tested concentrations. In addition, the production of TH1 cytokine (IFN-γ) rather than that of TH2 cytokine (IL-4) was enhanced by LAB cell wall extracts. Of ten LAB extracts, four (from L. acidophilus, L. bulgaricus, L. casei, and S. thermophiles) promoted both cell proliferating and TH1 cytokine production. These results suggested that these LAB could be used as probiotics to maintain immunity and homeostasis for astronauts in extreme space environment and for general people in normal life. PMID:26761877

  10. A gene network engineering platform for lactic acid bacteria

    PubMed Central

    Kong, Wentao; Kapuganti, Venkata S.; Lu, Ting

    2016-01-01

    Recent developments in synthetic biology have positioned lactic acid bacteria (LAB) as a major class of cellular chassis for applications. To achieve the full potential of LAB, one fundamental prerequisite is the capacity for rapid engineering of complex gene networks, such as natural biosynthetic pathways and multicomponent synthetic circuits, into which cellular functions are encoded. Here, we present a synthetic biology platform for rapid construction and optimization of large-scale gene networks in LAB. The platform involves a copy-controlled shuttle for hosting target networks and two associated strategies that enable efficient genetic editing and phenotypic validation. By using a nisin biosynthesis pathway and its variants as examples, we demonstrated multiplex, continuous editing of small DNA parts, such as ribosome-binding sites, as well as efficient manipulation of large building blocks such as genes and operons. To showcase the platform, we applied it to expand the phenotypic diversity of the nisin pathway by quickly generating a library of 63 pathway variants. We further demonstrated its utility by altering the regulatory topology of the nisin pathway for constitutive bacteriocin biosynthesis. This work demonstrates the feasibility of rapid and advanced engineering of gene networks in LAB, fostering their applications in biomedicine and other areas. PMID:26503255

  11. Removal of Paralytic Shellfish Toxins by Probiotic Lactic Acid Bacteria

    PubMed Central

    Vasama, Mari; Kumar, Himanshu; Salminen, Seppo; Haskard, Carolyn A.

    2014-01-01

    Paralytic shellfish toxins (PSTs) are non-protein neurotoxins produced by saltwater dinoflagellates and freshwater cyanobacteria. The ability of Lactobacillus rhamnosus strains GG and LC-705 (in viable and non-viable forms) to remove PSTs (saxitoxin (STX), neosaxitoxin (neoSTX), gonyautoxins 2 and 3 (GTX2/3), C-toxins 1 and 2 (C1/2)) from neutral and acidic solution (pH 7.3 and 2) was examined using HPLC. Binding decreased in the order of STX ~ neoSTX > C2 > GTX3 > GTX2 > C1. Removal of STX and neoSTX (77%–97.2%) was significantly greater than removal of GTX3 and C2 (33.3%–49.7%). There were no significant differences in toxin removal capacity between viable and non-viable forms of lactobacilli, which suggested that binding rather than metabolism is the mechanism of the removal of toxins. In general, binding was not affected by the presence of other organic molecules in solution. Importantly, this is the first study to demonstrate the ability of specific probiotic lactic bacteria to remove PSTs, particularly the most toxic PST-STX, from solution. Further, these results warrant thorough screening and assessment of safe and beneficial microbes for their usefulness in the seafood and water industries and their effectiveness in vivo. PMID:25046082

  12. A gene network engineering platform for lactic acid bacteria.

    PubMed

    Kong, Wentao; Kapuganti, Venkata S; Lu, Ting

    2016-02-29

    Recent developments in synthetic biology have positioned lactic acid bacteria (LAB) as a major class of cellular chassis for applications. To achieve the full potential of LAB, one fundamental prerequisite is the capacity for rapid engineering of complex gene networks, such as natural biosynthetic pathways and multicomponent synthetic circuits, into which cellular functions are encoded. Here, we present a synthetic biology platform for rapid construction and optimization of large-scale gene networks in LAB. The platform involves a copy-controlled shuttle for hosting target networks and two associated strategies that enable efficient genetic editing and phenotypic validation. By using a nisin biosynthesis pathway and its variants as examples, we demonstrated multiplex, continuous editing of small DNA parts, such as ribosome-binding sites, as well as efficient manipulation of large building blocks such as genes and operons. To showcase the platform, we applied it to expand the phenotypic diversity of the nisin pathway by quickly generating a library of 63 pathway variants. We further demonstrated its utility by altering the regulatory topology of the nisin pathway for constitutive bacteriocin biosynthesis. This work demonstrates the feasibility of rapid and advanced engineering of gene networks in LAB, fostering their applications in biomedicine and other areas. PMID:26503255

  13. Acetic acid bacteria isolated from grapes of South Australian vineyards.

    PubMed

    Mateo, E; Torija, M J; Mas, A; Bartowsky, E J

    2014-05-16

    Acetic acid bacteria (AAB) diversity from healthy, mould-infected and rot-affected grapes collected from three vineyards of Adelaide Hills (South Australia) was analyzed by molecular typing and identification methods. Nine different AAB species were identified from the 624 isolates recovered: Four species from Gluconobacter genus, two from Asaia and one from Acetobacter were identified by the analysis of 16S rRNA gene and 16S-23S rRNA gene internal transcribed spacer. However, the identification of other isolates that were assigned as Asaia sp. and Ameyamaea chiangmaiensis required more analysis for a correct species classification. The species of Gluconobacter cerinus was the main one identified; while one genotype of Asaia siamensis presented the highest number of isolates. The number of colonies recovered and genotypes identified was strongly affected by the infection status of the grapes; the rot-affected with the highest number. However, the species diversity was similar in all the cases. High AAB diversity was detected with a specific genotype distribution for each vineyard. PMID:24681711

  14. The use of propidium monoazide in conjunction with qPCR and Illumina sequencing to identify and quantify live yeasts and bacteria.

    PubMed

    Tantikachornkiat, Mansak; Sakakibara, Stacey; Neuner, Marissa; Durall, Daniel M

    2016-10-01

    Culture-independent methods of microbial identification have been developed, which allow for DNA extraction directly from environmental samples without subjecting microbes to growth on nutrient media. These methods often involve next generation DNA sequencing (NGS) for identifying microbes and qPCR for quantifying them. Despite the benefits of extracting all DNA from the sample, results may be compromised by amplifying DNA from dead cells. To address this short-coming, the use of propidium monoazide (PMA) has been used to deactivate DNA in non-viable cells. Nevertheless, its optimization has not been fully explored under a variety of conditions. In this study, we optimized the PMA method for both yeasts and bacteria. Specifically, we explored the effect different PMA concentrations and different cell densities had on DNA amplification (as part of next generation DNA sequencing) from both dead and viable bacterial and yeast cells. We found PMA was effective in eliminating DNA that was associated with dead yeast and bacterial cells for all cell concentrations. Nevertheless, DNA (extracted from viable yeast and bacterial cells) amplified most abundantly when PMA concentration was at 6μM and when yeast densities ranged between 10(6) to 10(7)CFU/mL and bacterial densities were approximately 10(8)CFU/mL. PMID:27371903

  15. Production of γ-Amino Butyric Acid in Tea Leaves wit Treatment of Lactic Acid Bacteria

    NASA Astrophysics Data System (ADS)

    Watanabe, Yuko; Hayakawa, Kiyoshi; Ueno, Hiroshi

    Lactic acid bacteria was searched for producing termented tea that contained a lot of γ-amino butyric acid(GABA). Also examined were the growth condition, GABA production and changes in catechin contents in the tea leaves. Lactobacillus brevis L12 was found to be suitable for the production of fermented tea since it gave as much GABA as gabaron tea when tea leaves being suspended with water at 10% and incubated for 4 days at 25°C. The amount of GABA produced was more than calculated based upon the content of glutamic acid in tea leaves. It is probable to assume that glutamate derived from glutamine and theanine is converted into GABA.

  16. Achievements and perspectives in yeast acetic acid-induced programmed cell death pathways.

    PubMed

    Guaragnella, Nicoletta; Antonacci, Lucia; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

    2011-10-01

    The use of non-mammalian model organisms, including yeast Saccharomyces cerevisiae, can provide new insights into eukaryotic PCD (programmed cell death) pathways. In the present paper, we report recent achievements in the elucidation of the events leading to PCD that occur as a response to yeast treatment with AA (acetic acid). In particular, ROS (reactive oxygen species) generation, cyt c (cytochrome c) release and mitochondrial function and proteolytic activity will be dealt with as they vary along the AA-PCD time course by using both wild-type and mutant yeast cells. Two AA-PCD pathways are described sharing common features, but distinct from one another with respect to the role of ROS and mitochondria, the former in which YCA1 acts upstream of cyt c release and caspase-like activation in a ROS-dependent manner and the latter in which cyt c release does not occur, but caspase-like activity increases, in a ROS-independent manner. PMID:21936848

  17. Performance of mass spectrometric identification of bacteria and yeasts routinely isolated in a clinical microbiology laboratory using MALDI-TOF MS

    PubMed Central

    Wang, Weiping; Xi, Haiyan; Huang, Mei; Wang, Jie; Fan, Ming; Chen, Yong; Shao, Haifeng

    2014-01-01

    Background Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is an emerging technology newly applied to identifying bacterial and yeast strains. The aim of this study was to evaluate the clinical performance of the VITEK® MS system in the identification of bacteria and yeast strains routinely isolated from clinical samples. Methods We prospectively analyzed routine MALDI-TOF mass spectrometry identification in parallel with conventional phenotypic identification of bacteria and yeasts regardless of phylum or source of isolation. Discordant results were resolved with 16S rDNA or internal transcribed spacer (ITS) gene sequencing. Colonies (a single deposit on a MALDI disposable target without any prior extraction step) were analyzed using the VITEK® MS system. Peptide spectra acquired by the system were compared with the VITEK® MS IVD database Version 2.0, and the identification scores were recorded. Results Of the 1,181 isolates (1,061 bacterial isolates and 120 yeast isolates) analyzed, 99.5% were correctly identified by MALDI-TOF mass spectrometry; 95.7% identified to the species level, 3.6% identified to the genus level, and 0.3% identified within a range of species belonging to different genera. Conversely, 0.1% of isolates were misidentified and 0.4% were unidentified, partly because the species were not included in the database. Re-testing using a second deposit provided a successful identification for 0.5% of isolates unidentified with the first deposit. Our results show that the VITEK® MS system has exceptional performance in identifying bacteria and yeast by comparing acquired peptide spectra to those contained in its database. Conclusions MALDI-TOF mass spectrometry is a rapid, accurate, and relatively inexpensive method for bacterial and yeast identification. Our results demonstrate that the VITEK® MS system is a fast and reliable technique, and has the potential to replace conventional phenotypic

  18. Transport and signaling via the amino acid binding site of the yeast Gap1 amino acid transceptor.

    PubMed

    Van Zeebroeck, Griet; Bonini, Beatriz Monge; Versele, Matthias; Thevelein, Johan M

    2009-01-01

    Transporter-related nutrient sensors, called transceptors, mediate nutrient activation of signaling pathways through the plasma membrane. The mechanism of action of transporting and nontransporting transceptors is unknown. We have screened 319 amino acid analogs to identify compounds that act on Gap1, a transporting amino acid transceptor in yeast that triggers activation of the protein kinase A pathway. We identified competitive and noncompetitive inhibitors of transport, either with or without agonist action for signaling, including nontransported agonists. Using substituted cysteine accessibility method (SCAM) analysis, we identified Ser388 and Val389 as being exposed into the amino acid binding site, and we show that agonist action for signaling uses the same binding site as used for transport. Our results provide the first insight, to our knowledge, into the mechanism of action of transceptors. They indicate that signaling requires a ligand-induced specific conformational change that may be part of but does not require the complete transport cycle. PMID:19060912

  19. Effect of fermented broth from lactic acid bacteria on pathogenic bacteria proliferation.

    PubMed

    Gutiérrez, S; Martínez-Blanco, H; Rodríguez-Aparicio, L B; Ferrero, M A

    2016-04-01

    In this study, the effect that 5 fermented broths of lactic acid bacteria (LAB) strains have on the viability or proliferation and adhesion of 7 potentially pathogenic microorganisms was tested. The fermented broth from Lactococcus lactis C660 had a growth inhibitory effect on Escherichia coli K92 that reached of 31%, 19% to Pseudomonas fluorescens, and 76% to Staphylococcus epidermidis. The growth of Staph. epidermidis was negatively affected to 90% by Lc. lactis 11454 broth, whereas the growth of P. fluorescens (25%) and both species of Staphylococcus (35% to Staphylococcus aureus and 76% to Staph. epidermidis) were inhibited when they were incubated in the presence of Lactobacillus casei 393 broth. Finally, the fermented broth of Lactobacillus rhamnosus showed an inhibitory effect on growth of E. coli K92, Listeria innocua, and Staph. epidermidis reached values of 12, 28, and 76%, respectively. Staphylococcus epidermidis was the most affected strain because the effect was detected from the early stages of growth and it was completely abolished. The results of bacterial adhesion revealed that broths from Lc. lactis strains, Lactobacillus paracasei, and Lb. rhamnosus caused a loss of E. coli K92 adhesion. Bacillus cereus showed a decreased of adhesion in the presence of the broths of Lc. lactis strains and Lb. paracasei. Listeria innocua adhesion inhibition was observed in the presence of Lb. paracasei broth, and the greatest inhibitory effect was registered when this pathogenic bacterium was incubated in presence of Lc. lactis 11454 broth. With respect to the 2 Pseudomonas, we observed a slight adhesion inhibition showed by Lactobacillus rhamnosus broth against Pseudomonas putida. These results confirm that the effect caused by the different LAB assayed is also broth- and species-specific and reveal that the broth from LAB tested can be used as functional bioactive compounds to regulate the adhesion and biofilm synthesis and ultimately lead to preventing food and

  20. Production of the antimalarial drug precursor artemisinic acid in engineered yeast.

    PubMed

    Ro, Dae-Kyun; Paradise, Eric M; Ouellet, Mario; Fisher, Karl J; Newman, Karyn L; Ndungu, John M; Ho, Kimberly A; Eachus, Rachel A; Ham, Timothy S; Kirby, James; Chang, Michelle C Y; Withers, Sydnor T; Shiba, Yoichiro; Sarpong, Richmond; Keasling, Jay D

    2006-04-13

    Malaria is a global health problem that threatens 300-500 million people and kills more than one million people annually. Disease control is hampered by the occurrence of multi-drug-resistant strains of the malaria parasite Plasmodium falciparum. Synthetic antimalarial drugs and malarial vaccines are currently being developed, but their efficacy against malaria awaits rigorous clinical testing. Artemisinin, a sesquiterpene lactone endoperoxide extracted from Artemisia annua L (family Asteraceae; commonly known as sweet wormwood), is highly effective against multi-drug-resistant Plasmodium spp., but is in short supply and unaffordable to most malaria sufferers. Although total synthesis of artemisinin is difficult and costly, the semi-synthesis of artemisinin or any derivative from microbially sourced artemisinic acid, its immediate precursor, could be a cost-effective, environmentally friendly, high-quality and reliable source of artemisinin. Here we report the engineering of Saccharomyces cerevisiae to produce high titres (up to 100 mg l(-1)) of artemisinic acid using an engineered mevalonate pathway, amorphadiene synthase, and a novel cytochrome P450 monooxygenase (CYP71AV1) from A. annua that performs a three-step oxidation of amorpha-4,11-diene to artemisinic acid. The synthesized artemisinic acid is transported out and retained on the outside of the engineered yeast, meaning that a simple and inexpensive purification process can be used to obtain the desired product. Although the engineered yeast is already capable of producing artemisinic acid at a significantly higher specific productivity than A. annua, yield optimization and industrial scale-up will be required to raise artemisinic acid production to a level high enough to reduce artemisinin combination therapies to significantly below their current prices. PMID:16612385

  1. The Fate of Acetic Acid during Glucose Co-Metabolism by the Spoilage Yeast Zygosaccharomyces bailii

    PubMed Central

    Rodrigues, Fernando; Sousa, Maria João; Ludovico, Paula; Santos, Helena; Côrte-Real, Manuela; Leão, Cecília

    2012-01-01

    Zygosaccharomyces bailii is one of the most widely represented spoilage yeast species, being able to metabolise acetic acid in the presence of glucose. To clarify whether simultaneous utilisation of the two substrates affects growth efficiency, we examined growth in single- and mixed-substrate cultures with glucose and acetic acid. Our findings indicate that the biomass yield in the first phase of growth is the result of the weighted sum of the respective biomass yields on single-substrate medium, supporting the conclusion that biomass yield on each substrate is not affected by the presence of the other at pH 3.0 and 5.0, at least for the substrate concentrations examined. In vivo 13C-NMR spectroscopy studies showed that the gluconeogenic pathway is not operational and that [2−13C]acetate is metabolised via the Krebs cycle leading to the production of glutamate labelled on C2, C3 and C4. The incorporation of [U-14C]acetate in the cellular constituents resulted mainly in the labelling of the protein and lipid pools 51.5% and 31.5%, respectively. Overall, our data establish that glucose is metabolised primarily through the glycolytic pathway, and acetic acid is used as an additional source of acetyl-CoA both for lipid synthesis and the Krebs cycle. This study provides useful clues for the design of new strategies aimed at overcoming yeast spoilage in acidic, sugar-containing food environments. Moreover, the elucidation of the molecular basis underlying the resistance phenotype of Z. bailii to acetic acid will have a potential impact on the improvement of the performance of S. cerevisiae industrial strains often exposed to acetic acid stress conditions, such as in wine and bioethanol production. PMID:23285028

  2. [Inhibitory activity of vaginal Lactobacillus bacteria on yeasts causing vulvovaginal candidiasis].

    PubMed

    Strus, Magdalena; Brzychczy-Włoch, Monika; Kucharska, Agnieszka; Gosiewski, Tomasz; Heczko, Piotr B

    2005-01-01

    Growing frequency of therapeutical failures of vulvovaginal candidiasis, resulting from resistance of certain species of Candida to imidazole agents, raises interest in the use of probiotics from Lactobacillus genera as prophylaxis. Unfortunately, little is known about inhibitory mechanisms of Lactobacillus on Candida. The aim of this study was to compare the activity of selected Lactobacillus species, representing the physiological vaginal flora, against Candida as well as investigation whether their inhibitory activity against Candida is related strictly to hydrogen peroxide and lactic acid production. 125 strains from vaginal smears of healthy women were classified by making use of phenotypic and genotypic methods. The majority of strains belonged to L. acidophilus: L. acidophilus sensu stricto, L. crispatus, L. gasseri and L. johnsonii as well as L. fermentum and L. plantarum species. Culture supernatants of selected 25 strains representing the isolated species were examined for their inhibitory activity against the growth of Candida albicans and C. glabrata. The results showed that the strongest and the fastest activity against C. albicans was demonstrated by L. delbrueckii strains, producing the largest quantities of hydrogen peroxide. On the other hand, extended activity, demonstrable after 24 hours, was shown by non-H2O2 producing L. plantarum supernatants. Growth of C. glabrata was not inhibited by any of the examined strains of Lactobacillus. Comparison of activity of live active cultures of Lactobacillus strains and their mixtures with this of pure H2O2 and lactic acid has shown that pure chemical compounds were less active than the cultures. This suggests that mixtures of Lactobacillus strains are in cooperation with each other using many different metabolites. PMID:16130291

  3. Hypolipidemic effects of lactic acid bacteria fermented cereal in rats

    PubMed Central

    2012-01-01

    Background The objectives of the present study were to investigate the efficacy of the mixed culture of Lactobacillus acidophilus (DSM 20242), Bifidobacterium bifidum (DSM 20082) and Lactobacillus helveticus (CK60) in the fermentation of maize and the evaluation of the effect of the fermented meal on the lipid profile of rats. Methods Rats were randomly assigned to 3 groups and each group placed on a Diet A (high fat diet into which a maize meal fermented with a mixed culture of Lb acidophilus (DSM 20242), B bifidum (DSM 20082) and Lb helveticus (CK 60) was incorporated), B (unfermented high fat diet) or C (commercial rat chow) respectively after the first group of 7 rats randomly selected were sacrificed to obtain the baseline data. Thereafter 7 rats each from the experimental and control groups were sacrificed weekly for 4 weeks and the plasma, erythrocytes, lipoproteins and organs of the rats were assessed for cholesterol, triglyceride and phospholipids. Results Our results revealed that the mixed culture of Lb acidophilus (DSM 20242), B bifidum (DSM 20082) and Lb helveticus (CK 60) were able to grow and ferment maize meal into ‘ogi’ of acceptable flavour. In addition to plasma and hepatic hypercholesterolemia and hypertriglyceridemia, phospholipidosis in plasma, as well as cholesterogenesis, triglyceride constipation and phospholipidosis in extra-hepatic tissues characterized the consumption of unfermented hyperlipidemic diets. However, feeding the animals with the fermented maize diet reversed the dyslipidemia. Conclusion The findings of this study indicate that consumption of mixed culture lactic acid bacteria (Lb acidophilus (DSM 20242), Bifidobacterium bifidum (DSM 20082) and Lb helveticus (CK 60) fermented food results in the inhibition of fat absorption. It also inhibits the activity of HMG CoA reductase. This inhibition may be by feedback inhibition or repression of the transcription of the gene encoding the enzyme via activation of the sterol

  4. Comparative acid tolerances and inhibitor sensitivities of isolated F-ATPases of oral lactic acid bacteria.

    PubMed Central

    Sturr, M G; Marquis, R E

    1992-01-01

    pH activity profiles and inhibitor sensitivities were compared for membrane ATPases isolated from three oral lactic acid bacteria, Lactobacillus casei ATCC 4646, Streptococcus mutans GS-5, and Streptococcus sanguis NCTC 10904, with, respectively, high, moderate, and low levels of acid tolerance. Membranes containing F1F0 ATPases were isolated by means of salt lysis of cells treated with muralytic enzymes. Membrane-free F1F0 complexes were then isolated from membranes by detergent extraction with Triton X-100 or octylglucoside. Finally, F1 complexes free of the proton-conducting F0 sector were obtained by washing membranes with buffers of low ionic strength. The pH activity profiles of the membrane-associated enzymes reflected the general acid tolerances of the organisms from which they were isolated; for example, pH optima were approximately 5.5, 6.0, and 7.0, respectively, for enzymes from L. casei, S. mutans, and S. sanguis. Roughly similar profiles were found for membrane-free F1F0 complexes, which were stabilized by phospholipids against loss of activity during storage. However, profiles for F1 enzymes were distinctly narrower, indicating that association with F0 and possibly other membrane components enhanced tolerance to both acid and alkaline media. All of the enzymes were found to have similar sensitivities to Al-F complexes, but only F1F0 enzymes were highly sensitive to dicyclohexylcarbodiimide. The procedures described for isolation of membrane-free F1F0 forms of the enzymes from oral lactic acid bacteria will be of use in future studies of the characteristics of the enzymes, especially in studies with liposomes. PMID:1386211

  5. Identification of acetic acid bacteria by restriction fragment length polymorphism analysis of a PCR-amplified fragment of the gene coding for 16S rRNA.

    PubMed

    Poblet, M; Rozès, N; Guillamón, J M; Mas, A

    2000-07-01

    Acetic acid bacteria (AAB) irreversibly spoil wines and represent a serious problem. Limited studies on the ecology of AAB during winemaking have been done due to the lack of rapid and precise techniques for their identification. RFLP analysis of PCR-amplified fragment of 16S rDNA was performed on AAB reference strains. The amplified rDNAs were approximately 870-bp long for all AAB species while no amplicons were detected for lactic acid bacteria and yeasts. Out of the four restriction enzymes tested, TaqI was the most efficient one and divided the studied AAB into six groups. However, complete differentiation among collection strains of Acetobacter pasteurianus and Gluconoacetobacter hansenii was not possible. PMID:10886617

  6. d-Amino Acid Catabolism Is Common Among Soil-Dwelling Bacteria

    PubMed Central

    Radkov, Atanas D; McNeill, Katlyn; Uda, Koji; Moe, Luke A

    2016-01-01

    Soil and rhizosphere environments were examined in order to determine the identity and relative abundance of bacteria that catabolize d- and l-amino acids as the sole source of carbon and nitrogen. All substrates were readily catabolized by bacteria from both environments, with most d-amino acids giving similar CFU counts to their l-amino acid counterparts. CFU count ratios between l- and d-amino acids typically ranged between 2 and 1. Isolates were phylogenetically typed in order to determine the identity of d-amino acid catabolizers. Actinobacteria, specifically the Arthrobacter genus, were abundant along with members of the α- and β-Proteobacteria classes. PMID:27169790

  7. D-Amino Acid Catabolism Is Common Among Soil-Dwelling Bacteria.

    PubMed

    Radkov, Atanas D; McNeill, Katlyn; Uda, Koji; Moe, Luke A

    2016-06-25

    Soil and rhizosphere environments were examined in order to determine the identity and relative abundance of bacteria that catabolize d- and l-amino acids as the sole source of carbon and nitrogen. All substrates were readily catabolized by bacteria from both environments, with most d-amino acids giving similar CFU counts to their l-amino acid counterparts. CFU count ratios between l- and d-amino acids typically ranged between 2 and 1. Isolates were phylogenetically typed in order to determine the identity of d-amino acid catabolizers. Actinobacteria, specifically the Arthrobacter genus, were abundant along with members of the α- and β-Proteobacteria classes. PMID:27169790

  8. Intersection of RNA Processing and the Type II Fatty Acid Synthesis Pathway in Yeast Mitochondria▿

    PubMed Central

    Schonauer, Melissa S.; Kastaniotis, Alexander J.; Hiltunen, J. Kalervo; Dieckmann, Carol L.

    2008-01-01

    Distinct metabolic pathways can intersect in ways that allow hierarchical or reciprocal regulation. In a screen of respiration-deficient Saccharomyces cerevisiae gene deletion strains for defects in mitochondrial RNA processing, we found that lack of any enzyme in the mitochondrial fatty acid type II biosynthetic pathway (FAS II) led to inefficient 5′ processing of mitochondrial precursor tRNAs by RNase P. In particular, the precursor containing both RNase P RNA (RPM1) and tRNAPro accumulated dramatically. Subsequent Pet127-driven 5′ processing of RPM1 was blocked. The FAS II pathway defects resulted in the loss of lipoic acid attachment to subunits of three key mitochondrial enzymes, which suggests that the octanoic acid produced by the pathway is the sole precursor for lipoic acid synthesis and attachment. The protein component of yeast mitochondrial RNase P, Rpm2, is not modified by lipoic acid in the wild-type strain, and it is imported in FAS II mutant strains. Thus, a product of the FAS II pathway is required for RNase P RNA maturation, which positively affects RNase P activity. In addition, a product is required for lipoic acid production, which is needed for the activity of pyruvate dehydrogenase, which feeds acetyl-coenzyme A into the FAS II pathway. These two positive feedback cycles may provide switch-like control of mitochondrial gene expression in response to the metabolic state of the cell. PMID:18779316

  9. The peculiarities of succinic acid production from rapeseed oil by Yarrowia lipolytica yeast.

    PubMed

    Kamzolova, Svetlana V; Vinokurova, Natalia G; Dedyukhina, Emiliya G; Samoilenko, Vladimir A; Lunina, Julia N; Mironov, Alexey A; Allayarov, Ramil K; Morgunov, Igor G

    2014-05-01

    The process of succinic acid (SA) production represents the combination of microbial synthesis of α-ketoglutaric acid from rapeseed oil by yeast Yarrowia lipolytica VKM Y-2412 and subsequent decarboxylation of α-ketoglutaric acid by hydrogen peroxide to SA that leads to the production of 69.0 g l(-1) of SA and 1.36 g l(-1) of acetic acid. SA was isolated from the culture broth filtrate in a crystalline form. The SA recovery from the culture filtrate has certain difficulties due to the presence of residual triglycerides of rapeseed oil. The effect of different methods of the culture filtrate treatment and various sorption materials on the coagulation of triglycerides was studied, and as a result, the precipitation of residual triglycerides by acetone was chosen. The subsequent isolation procedures involved the decomposition of H2O2 in the filtrate followed by filtrate bleaching and acidification with a mineral acid, evaporation of filtrate, and SA extraction with ethanol from the residue. The purity of crystalline SA isolated from the culture broth filtrate achieved 97.6-100 %. The product yield varied from 62.6 to 71.6 % depending on the acidity of the supernatant. PMID:24531240

  10. Fatty Acid Desaturase Mutants of Yeast: Growth Requirements and Electron Spin Resonance Spin-Label Distribution

    PubMed Central

    Wisnieski, Bernadine J.; Kiyomoto, Richard K.

    1972-01-01

    Two respiratory-sufficient and one respiratory-deficient (nuclear petite) strains of yeast Δ9-desaturase mutants were analyzed to determine which fatty acids would serve as replacements for the naturally occurring fatty acids, 16:1 Δ9cis and 18:1 Δ9cis. The requirement can be satisfied by several fatty acids differing in double-bond position, steric configuration, chain length, and degree of unsaturation. The features common to growth-supporting fatty acids are presented and the effects of varying the carbon source and temperature are considered. In addition, we illustrate several pitfalls encountered in membrane studies which exploit lipid-requiring organisms. Since the membrane fatty acid composition of these mutants can be modified readily, electron spin resonance spectroscopy is used to compare membranes of mutant strains enriched for different fatty acids. The lipid distribution pattern of the most commonly employed electron spin resonance spin-label, 12-nitroxide stearate, was ascertained and compared to that of 18:1 Δ9cis. PMID:4333377

  11. Effect of plant oils upon lipase and citric acid production in Yarrowia lipolytica yeast.

    PubMed

    Darvishi, Farshad; Nahvi, Iraj; Zarkesh-Esfahani, Hamid; Momenbeik, Fariborz

    2009-01-01

    The nonconventional yeast Yarrowia lipolytica degrades very efficiently hydrophobic substrates to produce organic acids, single-cell oil, lipases, and so forth. The aim of this study was to investigate the biochemical behavior and simultaneous production of valuable metabolites such as lipase, citric acid (CA), and single-cell protein (SCP) by Yarrowia lipolytica DSM 3286 grown on various plant oils as sole carbon source. Among tested plant oils, olive oil proved to be the best medium for lipase and CA production. The Y. lipolytica DSM 3286 produced 34.6 +/- 0.1 U/mL of lipase and also CA and SCP as by-product on olive oil medium supplemented with yeast extract. Urea, as organic nitrogen, was the best nitrogen source for CA production. The results of this study suggest that the two biotechnologically valuable products, lipase and CA, could be produced simultaneously by this strain using renewable low-cost substrates such as plant oils in one procedure. PMID:19826636

  12. Effect of Plant Oils upon Lipase and Citric Acid Production in Yarrowia lipolytica Yeast

    PubMed Central

    Darvishi, Farshad; Nahvi, Iraj; Zarkesh-Esfahani, Hamid; Momenbeik, Fariborz

    2009-01-01

    The nonconventional yeast Yarrowia lipolytica degrades very efficiently hydrophobic substrates to produce organic acids, single-cell oil, lipases, and so forth. The aim of this study was to investigate the biochemical behavior and simultaneous production of valuable metabolites such as lipase, citric acid (CA), and single-cell protein (SCP) by Yarrowia lipolytica DSM 3286 grown on various plant oils as sole carbon source. Among tested plant oils, olive oil proved to be the best medium for lipase and CA production. The Y. lipolytica DSM 3286 produced 34.6 ± 0.1 U/mL of lipase and also CA and SCP as by-product on olive oil medium supplemented with yeast extract. Urea, as organic nitrogen, was the best nitrogen source for CA production. The results of this study suggest that the two biotechnologically valuable products, lipase and CA, could be produced simultaneously by this strain using renewable low-cost substrates such as plant oils in one procedure. PMID:19826636

  13. Valproic Acid Affects Membrane Trafficking and Cell-Wall Integrity in Fission Yeast

    PubMed Central

    Miyatake, Makoto; Kuno, Takayoshi; Kita, Ayako; Katsura, Kosaku; Takegawa, Kaoru; Uno, Satoshi; Nabata, Toshiya; Sugiura, Reiko

    2007-01-01

    Valproic acid (VPA) is widely used to treat epilepsy and manic-depressive illness. Although VPA has been reported to exert a variety of biochemical effects, the exact mechanisms underlying its therapeutic effects remain elusive. To gain further insights into the molecular mechanisms of VPA action, a genetic screen for fission yeast mutants that show hypersensitivity to VPA was performed. One of the genes that we identified was vps45+, which encodes a member of the Sec1/Munc18 family that is implicated in membrane trafficking. Notably, several mutations affecting membrane trafficking also resulted in hypersensitivity to VPA. These include ypt3+ and ryh1+, both encoding a Rab family protein, and apm1+, encoding the μ1 subunit of the adaptor protein complex AP-1. More importantly, VPA caused vacuolar fragmentation and inhibited the glycosylation and the secretion of acid phosphatase in wild-type cells, suggesting that VPA affects membrane trafficking. Interestingly, the cell-wall-damaging agents such as micafungin or the inhibition of calcineurin dramatically enhanced the sensitivity of wild-type cells to VPA. Consistently, VPA treatment of wild-type cells enhanced their sensitivity to the cell-wall-digesting enzymes. Altogether, our results suggest that VPA affects membrane trafficking, which leads to the enhanced sensitivity to cell-wall damage in fission yeast. PMID:17287531

  14. High-Throughput Identification of Bacteria and Yeast by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry in Conventional Medical Microbiology Laboratories ▿

    PubMed Central

    van Veen, S. Q.; Claas, E. C. J.; Kuijper, Ed J.

    2010-01-01

    Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is suitable for high-throughput and rapid diagnostics at low costs and can be considered an alternative for conventional biochemical and molecular identification systems in a conventional microbiological laboratory. First, we evaluated MALDI-TOF MS using 327 clinical isolates previously cultured from patient materials and identified by conventional techniques (Vitek-II, API, and biochemical tests). Discrepancies were analyzed by molecular analysis of the 16S genes. Of 327 isolates, 95.1% were identified correctly to genus level, and 85.6% were identified to species level by MALDI-TOF MS. Second, we performed a prospective validation study, including 980 clinical isolates of bacteria and yeasts. Overall performance of MALDI-TOF MS was significantly better than conventional biochemical systems for correct species identification (92.2% and 83.1%, respectively) and produced fewer incorrect genus identifications (0.1% and 1.6%, respectively). Correct species identification by MALDI-TOF MS was observed in 97.7% of Enterobacteriaceae, 92% of nonfermentative Gram-negative bacteria, 94.3% of staphylococci, 84.8% of streptococci, 84% of a miscellaneous group (mainly Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella [HACEK]), and 85.2% of yeasts. MALDI-TOF MS had significantly better performance than conventional methods for species identification of staphylococci and genus identification of bacteria belonging to HACEK group. Misidentifications by MALDI-TOF MS were clearly associated with an absence of sufficient spectra from suitable reference strains in the MALDI-TOF MS database. We conclude that MALDI-TOF MS can be implemented easily for routine identification of bacteria (except for pneumococci and viridans streptococci) and yeasts in a medical microbiological laboratory. PMID:20053859

  15. Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites.

    PubMed

    Du, Huihui; Chen, Wenli; Cai, Peng; Rong, Xingmin; Dai, Ke; Peacock, Caroline L; Huang, Qiaoyun

    2016-01-01

    Soil components (e.g., clays, bacteria and humic substances) are known to produce mineral-organic composites in natural systems. Herein, batch sorption isotherms, isothermal titration calorimetry (ITC), and Cd K-edge EXAFS spectroscopy were applied to investigate the binding characteristics of Cd on montmorillonite(Mont)-humic acid(HA)-bacteria composites. Additive sorption and non-additive Cd(II) sorption behaviour is observed for the binary Mont-bacteria and ternary Mont-HA-bacteria composite, respectively. Specifically, in the ternary composite, the coexistence of HA and bacteria inhibits Cd adsorption, suggesting a "blocking effect" between humic acid and bacterial cells. Large positive entropies (68.1~114.4 J/mol/K), and linear combination fitting of the EXAFS spectra for Cd adsorbed onto Mont-bacteria and Mont-HA-bacteria composites, demonstrate that Cd is mostly bound to bacterial surface functional groups by forming inner-sphere complexes. All our results together support the assertion that there is a degree of site masking in the ternary clay mineral-humic acid-bacteria composite. Because of this, in the ternary composite, Cd preferentially binds to the higher affinity components-i.e., the bacteria. PMID:26792640

  16. Cd(II) Sorption on Montmorillonite-Humic acid-Bacteria Composites

    PubMed Central

    Du, Huihui; Chen, Wenli; Cai, Peng; Rong, Xingmin; Dai, Ke; Peacock, Caroline L.; Huang, Qiaoyun

    2016-01-01

    Soil components (e.g., clays, bacteria and humic substances) are known to produce mineral-organic composites in natural systems. Herein, batch sorption isotherms, isothermal titration calorimetry (ITC), and Cd K-edge EXAFS spectroscopy were applied to investigate the binding characteristics of Cd on montmorillonite(Mont)-humic acid(HA)-bacteria composites. Additive sorption and non-additive Cd(II) sorption behaviour is observed for the binary Mont-bacteria and ternary Mont-HA-bacteria composite, respectively. Specifically, in the ternary composite, the coexistence of HA and bacteria inhibits Cd adsorption, suggesting a “blocking effect” between humic acid and bacterial cells. Large positive entropies (68.1 ~ 114.4 J/mol/K), and linear combination fitting of the EXAFS spectra for Cd adsorbed onto Mont-bacteria and Mont-HA-bacteria composites, demonstrate that Cd is mostly bound to bacterial surface functional groups by forming inner-sphere complexes. All our results together support the assertion that there is a degree of site masking in the ternary clay mineral-humic acid-bacteria composite. Because of this, in the ternary composite, Cd preferentially binds to the higher affinity components-i.e., the bacteria. PMID:26792640

  17. Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments.

    PubMed

    Hakim, Hakimullah; Alam, Md Shahin; Sangsriratanakul, Natthanan; Nakajima, Katsuhiro; Kitazawa, Minori; Ota, Mari; Toyofuku, Chiharu; Yamada, Masashi; Thammakarn, Chanathip; Shoham, Dany; Takehara, Kazuaki

    2016-08-01

    The capacity of slightly acidic hypochlorous acid water (SAHW), in both liquid and spray form, to inactivate bacteria was evaluated as a potential candidate for biosecurity enhancement in poultry production. SAHW (containing 50 or 100 ppm chlorine, pH 6) was able to inactivate Escherichia coli and Salmonella Infantis in liquid to below detectable levels (≤2.6 log10 CFU/ml) within 5 sec of exposure. In addition, SAHW antibacterial capacity was evaluated by spraying it using a nebulizer into a box containing these bacteria, which were present on the surfaces of glass plates and rayon sheets. SAHW was able to inactivate both bacterial species on the glass plates (dry condition) and rayon sheets within 5 min spraying and 5 min contact times, with the exception of 50 ppm SAHW on the rayon sheets. Furthermore, a corrosivity test determined that SAHW does not corrode metallic objects, even at the longest exposure times (83 days). Our findings demonstrate that SAHW is a good candidate for biosecurity enhancement in the poultry industry. Spraying it on the surfaces of objects, eggshells, egg incubators and transport cages could reduce the chances of contamination and disease transmission. These results augment previous findings demonstrating the competence of SAHW as an anti-viral disinfectant. PMID:27052464

  18. Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments

    PubMed Central

    HAKIM, Hakimullah; ALAM, Md. Shahin; SANGSRIRATANAKUL, Natthanan; NAKAJIMA, Katsuhiro; KITAZAWA, Minori; OTA, Mari; TOYOFUKU, Chiharu; YAMADA, Masashi; THAMMAKARN, Chanathip; SHOHAM, Dany; TAKEHARA, Kazuaki

    2016-01-01

    The capacity of slightly acidic hypochlorous acid water (SAHW), in both liquid and spray form, to inactivate bacteria was evaluated as a potential candidate for biosecurity enhancement in poultry production. SAHW (containing 50 or 100 ppm chlorine, pH 6) was able to inactivate Escherichia coli and Salmonella Infantis in liquid to below detectable levels (≤2.6 log10 CFU/ml) within 5 sec of exposure. In addition, SAHW antibacterial capacity was evaluated by spraying it using a nebulizer into a box containing these bacteria, which were present on the surfaces of glass plates and rayon sheets. SAHW was able to inactivate both bacterial species on the glass plates (dry condition) and rayon sheets within 5 min spraying and 5 min contact times, with the exception of 50 ppm SAHW on the rayon sheets. Furthermore, a corrosivity test determined that SAHW does not corrode metallic objects, even at the longest exposure times (83 days). Our findings demonstrate that SAHW is a good candidate for biosecurity enhancement in the poultry industry. Spraying it on the surfaces of objects, eggshells, egg incubators and transport cages could reduce the chances of contamination and disease transmission. These results augment previous findings demonstrating the competence of SAHW as an anti-viral disinfectant. PMID:27052464

  19. Bacillus spp. produce antibacterial activities against lactic acid bacteria that contaminate fuel ethanol plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) frequently contaminate commercial fuel ethanol fermentations, reducing yields and decreasing profitability of biofuel production. Microorganisms from environmental sources in different geographic regions of Thailand were tested for antibacterial activity against LAB. Fou...

  20. Yeasts that utilize lactose in sweet whey

    SciTech Connect

    Gholson, J.H.; Gough, R.H.

    1980-01-01

    Since processing costs are usually higher for whey than for other available food or feed nutrients, only about one-third of whey produced in the US is used by food and feed industries. As a result whey disposal costs are a problem. Further; when whey is disposed of through municipal sewerage systems, the lactose present is changed by bacteria to lactic acid which tends to act as a preservative and retards further oxidation of whey constituents. This article describes a method of utilizing lactose-fermenting yeasts to produce large quantities of yeast cells, single-cell protein. Kluveromyces fragilis was found to be the most effective yeast species and the yeast cells produced could be used as a natural food or feed additive. Results of this study determined that certain methods and yeast strains could reduce whey-related pollution and thus help reduce costs of whey disposal.

  1. The production of succinic acid by yeast Yarrowia lipolytica through a two-step process.

    PubMed

    Kamzolova, Svetlana V; Vinokurova, Natalia G; Shemshura, Olga N; Bekmakhanova, Nadiya E; Lunina, Julia N; Samoilenko, Vladimir A; Morgunov, Igor G

    2014-09-01

    The production of α-ketoglutaric acid by yeast Yarrowia lipolytica VKMY-2412 from ethanol and its subsequent chemical conversion to succinic acid (SA) were investigated. A highly effective and environmentally friendly process of α-ketoglutaric acid production was developed using a special pH-controlling strategy, in which the titration of the culture broth with KOH in the acid-formation phase was minimal, that allowed accumulation of only low amounts of inorganic wastes in the course of SA recovery. The culture broth filtrate containing α-ketoglutaric acid (88.7 g l(-1)) was directly employed for SA production; the amount of SA produced comprised 71.7 g l(-1) with the yield of 70% from ethanol consumed. SA was isolated from the culture broth filtrate in a crystalline form with the purity of 100%. The yield of isolated SA was as high as 72% of its amount in the culture broth filtrate. The antimicrobial and nematocidic effects of SA of microbial origin on pathogenic organisms that cause human and plant diseases were revealed for the first time. PMID:24972816

  2. Improving polyketide and fatty acid synthesis by engineering of the yeast acetyl-CoA carboxylase.

    PubMed

    Choi, Jin Wook; Da Silva, Nancy A

    2014-10-10

    Polyketides and fatty acids are important in the production of pharmaceuticals, industrial chemicals, and biofuels. The synthesis of the malonyl-CoA building block, catalyzed by acetyl-CoA carboxylase (Acc1), is considered a limiting step to achieving high titers of polyketides and fatty acids in Saccharomyces cerevisiae. Acc1 is deactivated by AMP-activated serine/threonine protein kinase (Snf1) when glucose is depleted. To prevent this deactivation, the enzyme was aligned with the Rattus norvegicus (rat) Acc1 to identify a critical amino acid (Ser-1157) for phosphorylation and deactivation. Introduction of a S1157A mutation into Acc1 resulted in 9-fold higher specific activity following glucose depletion. The enzyme was tested in yeast engineered to produce the polyketide 6-methylsalisylic acid (6-MSA). Both 6-MSA and native fatty acid levels increased by 3-fold. Utilization of this modified Acc1 enzyme will also be beneficial for other products built from malonyl-CoA. PMID:25078432

  3. Lactic Acid Bacterium and Yeast Microbiotas of 19 Sourdoughs Used for Traditional/Typical Italian Breads: Interactions between Ingredients and Microbial Species Diversity

    PubMed Central

    Minervini, Fabio; Di Cagno, Raffaella; Lattanzi, Anna; Antonielli, Livio; Cardinali, Gianluigi; Cappelle, Stefan; Gobbetti, Marco

    2012-01-01

    The study of the microbiotas of 19 Italian sourdoughs used for the manufacture of traditional/typical breads allowed the identification, through a culture-dependent approach, of 20 and 4 species of lactic acid bacteria (LAB) and yeasts, respectively. Numerically, the most frequent LAB isolates were Lactobacillus sanfranciscensis (ca. 28% of the total LAB isolates), Lactobacillus plantarum (ca. 16%), and Lactobacillus paralimentarius (ca. 14%). Saccharomyces cerevisiae was identified in 16 sourdoughs. Candida humilis, Kazachstania barnettii, and Kazachstania exigua were also identified. As shown by principal component analysis (PCA), a correlation was found between the ingredients, especially the type of flour, the microbial community, and the biochemical features of sourdoughs. Triticum durum flours were characterized by the high level of maltose, glucose, fructose, and free amino acids (FAA) correlated with the sole or main presence of obligately heterofermentative LAB, the lowest number of facultatively heterofermentative strains, and the low cell density of yeasts in the mature sourdoughs. This study highlighted, through a comprehensive and comparative approach, the dominant microbiotas of 19 Italian sourdoughs, which determined some of the peculiarities of the resulting traditional/typical Italian breads. PMID:22156414

  4. Evaluating Rare Amino Acid Substitutions (RGC_CAMs) in a Yeast Model Clade

    PubMed Central

    Polzin, Kenneth; Rokas, Antonis

    2014-01-01

    When inferring phylogenetic relationships, not all sites in a sequence alignment are equally informative. One recently proposed approach that takes advantage of this inequality relies on sites that contain amino acids whose replacement requires multiple substitutions. Identifying these so-called RGC_CAM substitutions (after Rare Genomic Changes as Conserved Amino acids-Multiple substitutions) requires that, first, at any given site in the amino acid sequence alignment, there must be a minimum of two different amino acids; second, each amino acid must be present in at least two taxa; and third, the amino acids must require a minimum of two nucleotide substitutions to replace each other. Although theory suggests that RGC_CAM substitutions are expected to be rare and less likely to be homoplastic, the informativeness of RGC_CAM substitutions has not been extensively evaluated in biological data sets. We investigated the quality of RGC_CAM substitutions by examining their degree of homoplasy and internode certainty in nearly 2.7 million aligned amino acid sites from 5,261 proteins from five species belonging to the yeast Saccharomyces sensu stricto clade whose phylogeny is well-established. We identified 2,647 sites containing RGC_CAM substitutions, a number that contrasts sharply with the 100,887 sites containing RGC_non-CAM substitutions (i.e., changes between amino acids that require only a single nucleotide substitution). We found that RGC_CAM substitutions had significantly lower homoplasy than RGC_non-CAM ones; specifically RGC_CAM substitutions showed a per-site average homoplasy index of 0.100, whereas RGC_non-CAM substitutions had a homoplasy index of 0.215. Internode certainty values were also higher for sites containing RGC_CAM substitutions than for RGC_non-CAM ones. These results suggest that RGC_CAM substitutions possess a strong phylogenetic signal and are useful markers for phylogenetic inference despite their rarity. PMID:24637883

  5. Analysis of moisture content, acidity and contamination by yeast and molds in Apis mellifera L. honey from central Brazil

    PubMed Central

    Ananias, Karla Rubia; de Melo, Adriane Alexandre Machado; de Moura, Celso José

    2013-01-01

    The development of mold of environmental origin in honey affects its quality and leads to its deterioration, so yeasts and molds counts have been used as an important indicator of hygiene levels during its processing, transportation and storage. The aim of this study was to evaluate the levels of yeasts and molds contamination and their correlation with moisture and acidity levels in Apis mellifera L. honey from central Brazil. In 20% of the samples, the yeasts and molds counts exceeded the limit established by legislation for the marketing of honey in the MERCOSUR, while 42.8% and 5.7% presented above-standard acidity and moisture levels, respectively. Although samples showed yeasts and molds counts over 1.0 × 102 UFC.g−1, there was no correlation between moisture content and the number of microorganisms, since, in part of the samples with above-standard counts, the moisture level was below 20%. In some samples the acidity level was higher than that established by legislation, but only one sample presented a yeasts and molds count above the limit established by MERCOSUR, which would suggest the influence of the floral source on this parameter. In general, of the 35 samples analyzed, the quality was considered inadequate in 45.7% of cases. PMID:24516434

  6. Characterization of the spoilage lactic acid bacteria in “sliced vacuum-packed cooked ham”

    PubMed Central

    Kalschne, Daneysa Lahis; Womer, Rute; Mattana, Ademir; Sarmento, Cleonice Mendes Pereira; Colla, Luciane Maria; Colla, Eliane

    2015-01-01

    The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc / Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus , following by Lactobacillus sakei and Leuconostoc mesentereoides ; the Enterococcus sp. was not present in the samples. PMID:26221105

  7. Selection of lactic acid bacteria from Brazilian kefir grains for potential use as starter or probiotic cultures.

    PubMed

    Zanirati, Débora Ferreira; Abatemarco, Mário; Sandes, Sávio Henrique de Cicco; Nicoli, Jacques Robert; Nunes, Álvaro Cantini; Neumann, Elisabeth

    2015-04-01

    Brazilian kefir is a homemade fermented beverage that is obtained by incubating milk or a brown sugar solution with kefir grains that contribute their different microbiological compositions. It is highly important to isolate and characterize microorganisms from Brazilian kefir grains to obtain starter cultures for the industrial production of a standardized commercial kefir. Thus, the present study aimed to isolate lactic acid bacteria from eight kefir grains that were propagated in milk or sugar solutions from five different locations in Brazil and to select Lactobacillus isolates based on desirable in vitro probiotic properties. One hundred eight isolates from both substrates were identified by amplified ribosomal DNA restriction analysis and/or 16S rRNA gene sequencing and were determined to belong to the following 11 species from the genera: Lactococcus, Leuconostoc, Lactobacillus (L.), and Oenococcus. Leuconostoc mesenteroides, Lactobacillus kefiri, and Lactobacillus kefiranofaciens were isolated only from milk grains, whereas Lactobacillus perolens, Lactobacillus parafarraginis, Lactobacillus diolivorans, and Oenococcus oeni were isolated exclusively from sugar water grains. When the microbial compositions of four kefir grains were evaluated with culture-independent analyses, L. kefiranofaciens was observed to predominant in milk grains, whereas Lactobacillus hilgardii was most abundant in sugar water kefir. Unfortunately, L. hilgardii was not isolated from any grain, although this bacteria was detected with a culture-independent methodology. Fifty-two isolated Lactobacilli were tested for gastric juice and bile salt tolerance, antagonism against pathogens, antimicrobial resistance, and surface hydrophobicity. Three Lactobacillus strains (L. kefiranofaciens 8U, L. diolivorans 1Z, and Lactobacillus casei 17U) could be classified as potential probiotics. In conclusion, several lactic acid bacteria that could be used in combination with yeasts as starter

  8. Stoicheiometrical proton and potassium ion movements accompanying the absorption of amino acids by the yeast Saccharomyces carlsbergensis

    PubMed Central

    Eddy, A. A.; Nowacki, J. A.

    1971-01-01

    1. Proton uptake into the yeast Saccharomyces carlsbergensis, was studied at pH4.5–5.5 in the presence of both antimycin and 2-deoxyglucose to inhibit energy metabolism. Previous work had shown that the cells then absorbed about 20nmol of glycine or l-phenylalanine against a considerable amino acid concentration gradient. The addition of the amino acid immediately stimulated the rate of uptake of protons two- to three-fold. About 2 extra equivalents of H+ accompanied a given amount of the amino acids into the yeast preparations exposed to the metabolic inhibitors for 2–4min and about 1.2 equivalents after 20min exposure. 2. Analogous observations were made during serial additions of glycine, l-phenylalanine, l-leucine and l-lysine to preparations lacking the metabolic inhibitors and deficient in substrates needed for energy metabolism. In fresh cellular preparations the influx of glycine was then closely coupled to a stimulated flow of 2.1 equiv. of H+ into the yeast. A similar number of K+ ions left the cells. About 30% of the extra protons was subsequently ejected from the yeast. Deoxyglucose and antimycin together inhibited the ejection of protons. When the yeast had been fed with glucose energy metabolism was stimulated and almost as many protons as were absorbed with the amino acid were apparently ejected again. 3. Yeast preparations containing Na+, instead of K+, as the principal cation absorbed about 1 extra equivalent of H+ after the addition of phenylalanine, glycine or leucine. This response was not observed in the presence of both deoxyglucose and antimycin. 4. The observations show that H+ and, in certain circumstances, K+ are co-substrates in the transport of the amino acids into the yeast. An analogy is drawn with the roles of Na+ and K+ as co-substrates in certain mammalian systems. The results lead to various models relating the physical flow of the co-substrate ions on the amino acid carrier to the transduction of chemical energy in an

  9. Genotypic identification of some lactic acid bacteria by amplified fragment length polymorphism analysis and investigation of their potential usage as starter culture combinations in Beyaz cheese manufacture.

    PubMed

    Karahan, A G; Başyiğit Kiliç, G; Kart, A; Sanlidere Aloğlu, H; Oner, Z; Aydemir, S; Erkuş, O; Harsa, S

    2010-01-01

    In this study, 2 different starter culture combinations were prepared for cheesemaking. Starter culture combinations were formed from 8 strains of lactic acid bacteria. They were identified as Lactococcus lactis ssp. lactis (2 strains), Lactobacillus plantarum (5 strains), and Lactobacillus paraplantarum (1 strain) by amplified fragment length polymorphism analysis. The effects of these combinations on the physicochemical and microbiological properties of Beyaz cheeses were investigated. These cheeses were compared with Beyaz cheeses that were produced with a commercial starter culture containing Lc. lactis ssp. lactis and Lc. lactis ssp. cremoris as control. All cheeses were ripened in brine at 4 degrees C for 90 d. Dry matter, fat in dry matter, titratable acidity, pH, salt in dry matter, total N, water-soluble N, and ripening index were determined. Sodium dodecyl sulfate-PAGE patterns of cheeses showed that alpha(S)-casein and beta-casein degraded slightly during the ripening period. Lactic acid bacteria, total mesophilic aerobic bacteria, yeast, molds, and coliforms were also counted. All analyses were repeated twice during d 7, 30, 60, and 90. The starter culture combinations were found to be significantly different from the control group in pH, salt content, and lactobacilli, lactococci, and total mesophilic aerobic bacteria counts, whereas the cheeses were similar in fat, dry matter content, and coliform, yeast, and mold counts. The sensory analysis of cheeses indicated that textural properties of control cheeses presented somewhat lower scores than those of the test groups. The panelists preferred the tastes of treatment cheeses, whereas cheeses with starter culture combinations and control cheeses had similar scores for appearance and flavor. These results indicated that both starter culture combinations are suitable for Beyaz cheese production. PMID:20059897

  10. Probiotic lactic acid bacteria – the fledgling cuckoos of the gut?

    PubMed Central

    Berstad, Arnold; Raa, Jan; Midtvedt, Tore; Valeur, Jørgen

    2016-01-01

    It is tempting to look at bacteria from our human egocentric point of view and label them as either ‘good’ or ‘bad’. However, a microbial society has its own system of government – ‘microcracy’ – and its own rules of play. Lactic acid bacteria are often referred to as representatives of the good ones, and there is little doubt that those belonging to the normal intestinal flora are beneficial for human health. But we should stop thinking of lactic acid bacteria as always being ‘friendly’ – they may instead behave like fledgling cuckoos. PMID:27235098

  11. Microbial dynamics of Castelmagno PDO, a traditional Italian cheese, with a focus on lactic acid bacteria ecology.

    PubMed

    Dolci, Paola; Alessandria, Valentina; Rantsiou, Kalliopi; Rolle, Luca; Zeppa, Giuseppe; Cocolin, Luca

    2008-03-20

    The dynamics of dominant microflora throughout the manufacture and ripening processes were evaluated in three batches of traditional Castelmagno PDO cheese. Milk, curd and cheese samples, at different stages during cheesemaking, were collected and subjected to culture-dependent and -independent analysis. Traditional plating and genetic identification of lactic acid bacteria (LAB) isolates, and PCR-DGGE analysis of V1 region of 16S rRNA gene were carried out. The collected samples were also monitored by HPLC for the presence of organic acids, sugars and ketones. LAB resulted to be the prevailing microflora in all production stages although enterococci, coagulase-negative cocci and yeasts also showed considerable viable counts probably related to the presence, in the dairy samples analysed, of free short-chain fatty acids detected by HPLC. Lactococcus lactis subsp. lactis was the species most frequently isolated during Castelmagno PDO manufacture, while Lactobacillus plantarum and Lactobacillus paracasei were isolated with the highest frequencies from ripened Castelmagno PDO cheese samples. Occasionally strains of Lactobacillus delbrueckii subsp. lactis, Lactobacillus coryniformis subsp. torquens and Lactobacillus casei were isolated. The results obtained on Castelmagno PDO microflora underlines a partial correspondence between culture-dependent method and DGGE analysis. Thus, in this study, it is highlighted once more the importance to combine molecular culture-independent approaches with classical microbiological methods for the study of complex environmental communities occurring in food matrices. PMID:18272246

  12. SAGA is an essential in vivo target of the yeast acidic activator Gal4p

    PubMed Central

    Bhaumik, Sukesh R.; Green, Michael R.

    2001-01-01

    Despite major advances in characterizing the eukaryotic transcriptional machinery, the function of promoter-specific transcriptional activators (activators) is still not understood. For example, in no case have the direct in vivo targets of a transcriptional activator been unambiguously identified, nor has it been resolved whether activators have a single essential target or multiple redundant targets. Here we address these issues for the prototype acidic activator yeast Gal4p. Gal4p binds to the upstream activating sequence (UAS) of GAL1 and several other GAL genes and stimulates transcription in the presence of galactose. Previous studies have shown that GAL1 transcription is dependent on the yeast SAGA (Spt/Ada/GCN5/acetyltransferase) complex. Using formaldehyde-based in vivo cross-linking, we show that the Gal4p activation domain recruits SAGA to the GAL1 UAS. If SAGA is not recruited to the UAS, the preinitiation complex (PIC) fails to assemble at the GAL1 core promoter, and transcription does not occur. SAGA, but not other transcription components, is also recruited by the Gal4p activation domain to a plasmid containing minimal Gal4p-binding sites. Recruitment of SAGA by Gal4p and stimulation of PIC assembly is dependent on several SAGA subunits but not the SAGA histone acetyl-transferase (HAT) GCN5. Based on these and other results, we conclude that SAGA is an essential target of Gal4p that, following recruitment to the UAS, facilitates PIC assembly and transcription. PMID:11485988

  13. Distinct Amino Acid Compositional Requirements for Formation and Maintenance of the [PSI+] Prion in Yeast

    PubMed Central

    MacLea, Kyle S.; Paul, Kacy R.; Ben-Musa, Zobaida; Waechter, Aubrey; Shattuck, Jenifer E.; Gruca, Margaret

    2014-01-01

    Multiple yeast prions have been identified that result from the structural conversion of proteins into a self-propagating amyloid form. Amyloid-based prion activity in yeast requires a series of discrete steps. First, the prion protein must form an amyloid nucleus that can recruit and structurally convert additional soluble proteins. Subsequently, maintenance of the prion during cell division requires fragmentation of these aggregates to create new heritable propagons. For the Saccharomyces cerevisiae prion protein Sup35, these different activities are encoded by different regions of the Sup35 prion domain. An N-terminal glutamine/asparagine-rich nucleation domain is required for nucleation and fiber growth, while an adjacent oligopeptide repeat domain is largely dispensable for prion nucleation and fiber growth but is required for chaperone-dependent prion maintenance. Although prion activity of glutamine/asparagine-rich proteins is predominantly determined by amino acid composition, the nucleation and oligopeptide repeat domains of Sup35 have distinct compositional requirements. Here, we quantitatively define these compositional requirements in vivo. We show that aromatic residues strongly promote both prion formation and chaperone-dependent prion maintenance. In contrast, nonaromatic hydrophobic residues strongly promote prion formation but inhibit prion propagation. These results provide insight into why some aggregation-prone proteins are unable to propagate as prions. PMID:25547291

  14. Affinity chromatography of yeast alpha-glucosidase using ligand-mediated chromatography on immobilized phenylboronic acids.

    PubMed Central

    Myöhänen, T A; Bouriotis, V; Dean, P D

    1981-01-01

    The synthesis of 3-nitro-4-(6-aminohexylamido)phenylboronic acid is described. The properties of two novel forms of immobilized phenylboronate agarose adsorbents [m-aminophenylboronic acid-Matrex Gel and 3-nitro-4-(6-aminohexylamido)phenylboronic acid-Sepharose CL-6B] were investigated. Both gels bind and selectively retard the glycoprotein alpha-glucosidase from yeast. The retardation is affected by following parameters: (i) pH, (ii) presence of sugar, (iii) concentration of sugar and (iv) buffer species (especially triethanolamine). Five sugars were studied, namely sorbitol, fructose, ribose, glucose and maltose. The concentration of sugar required to produce significant retardation increased in the above order, whereas the ability of sugar to form a complex with boron decreases in the same order. These effects were observed with crude as well as pure enzyme. Since alpha-glucosidase is a glycoprotein, it is proposed that this protein is mainly bound to these immobilized phenylboronates via sugar (glyco) residues. Displacement of the enzyme from the column is effected by the sugar in the buffer (or in a preincubation mixture). However, the marked pH-dependence (this retardation effect could only be observed at pH 7.4) suggests that these results are not due solely to hydrophobic or ionic mechanisms and are more complex than simple sugar-phenylboronic acid interactions. PMID:7034722

  15. Methyl jasmonate, yeast extract and sucrose stimulate phenolic acids accumulation in Eryngium planum L. shoot cultures.

    PubMed

    Kikowska, Małgorzata; Kędziora, Izabela; Krawczyk, Aldona; Thiem, Barbara

    2015-01-01

    Eryngium planum L. has been reported as a medicinal plant used in traditional medicine in Europe. The tissue cultures may be an alternative source of the biomass rich in desired bioactive compounds. The purpose of this study was to investigate the influence of the biotechnological techniques on the selected phenolic acids accumulation in the agitated shoot cultures of E. planum. Qualitative and quantitative analyses of those compounds in 50% aqueous - methanolic extracts from the biomass were conducted by applying the HPLC method. Methyl jasmonate (MeJA), yeast extract (YE) and sucrose (Suc) stimulated accumulation of the phenolic acids: rosmarinic (RA), chlorogenic (CGA) and caffeic (CA) in in vitro shoot cultures. Cultivation of shoots in liquid MS media supplemented with 1.0 mg L(-1) 6-benzyladenine and 0.1 mg L(-1) indole-3-acetic acid in the presence of 100 µM MeJA for 48h was an optimum condition of elicitation and resulted in approximately 4.5-fold increased content of RA + CGA + CA in plant material compared to the control (19.795 mg g(-1) DW, 4.36 mg g(-1) DW, respectively). The results provide the first evidence that the selected phenolic acids can be synthesized in elicited shoot cultures of flat sea holly in higher amount than in untreated shoots. PMID:25856557

  16. Acetic acid bacteria in traditional balsamic vinegar: phenotypic traits relevant for starter cultures selection.

    PubMed

    Gullo, Maria; Giudici, Paolo

    2008-06-30

    This review focuses on acetic acid bacteria in traditional balsamic vinegar process. Although several studies are available on acetic acid bacteria ecology, metabolism and nutritional requirements, their activity as well as their technological traits in homemade vinegars as traditional balsamic vinegar is not well known. The basic technology to oxidise cooked grape must to produce traditional balsamic vinegar is performed by the so called "seed-vinegar" that is a microbiologically undefined starter culture obtained from spontaneous acetification of previous raw material. Selected starter cultures are the main technological improvement in order to innovate traditional balsamic vinegar production but until now they are rarely applied. To develop acetic acid bacteria starter cultures, selection criteria have to take in account composition of raw material, acetic acid bacteria metabolic activities, applied technology and desired characteristics of the final product. For traditional balsamic vinegar, significative phenotypical traits of acetic acid bacteria have been highlighted. Basic traits are: ethanol preferred and efficient oxidation, fast rate of acetic acid production, tolerance to high concentration of acetic acid, no overoxidation and low pH resistance. Specific traits are tolerance to high sugar concentration and to a wide temperature range. Gluconacetobacter europaeus and Acetobacter malorum strains can be evaluated to develop selected starter cultures since they show one or more suitable characters. PMID:18177968

  17. Isolation of lactic acid bacteria with potential protective culture characteristics from fruits

    NASA Astrophysics Data System (ADS)

    Hashim, Nurul Huda; Sani, Norrakiah Abdullah

    2015-09-01

    Lactic acid bacteria are also known as beneficial microorganisms abundantly found in fermented food products. In this study, lactic acid bacteria were isolated from fresh cut fruits obtained from local markets. Throughout the isolation process from 11 samples of fruits, 225 presumptive lactic acid bacteria were isolated on MRS agar medium. After catalase and oxidase tests, 149 resulted to fit the characteristics of lactic acid bacteria. Further identification using Gram staining was conducted to identify the Gram positive bacteria. After this confirmation, the fermentation characteristics of these isolates were identified. It was found that 87 (58.4%) isolates were heterofermentative, while the rest of 62 (41.6%) are homofermentative lactic acid bacteria. Later, all these isolates were investigated for the ability to inhibit growth of Staphylococcus aureus using agar spot assay method. Seven (4.7%) isolates showed strong antagonistic capacity, while 127 (85.2%) and 8 (5.4%) isolates have medium and weak antagonistic capacity, respectively. The other 7 (4.7%) isolates indicated to have no antagonistic effect on S. aureus. Results support the potential of LAB isolated in this study which showed strong antagonistic activity against S. aureus may be manipulated to become protective cultures in food products. While the homofermentative or heterofermentative LAB can be utilized in fermentation of food and non-food products depending on the by-products required during the fermentation.

  18. Putrescine production from different amino acid precursors by lactic acid bacteria from wine and cider.

    PubMed

    Costantini, Antonella; Pietroniro, Roberta; Doria, Francesca; Pessione, Enrica; Garcia-Moruno, Emilia

    2013-07-01

    The aim of this work was to study the production of biogenic amines and particularly putrescine in lactic acid bacteria (LAB) related to wine and cider. We applied an analytical protocol that involves the use of PCR and TLC techniques to determine the production of putrescine from different precursors. Moreover, we also studied the ability of the Lactobacillus and Pediococcus tested to produce histamine and tyramine. The results showed that the majority of the Lactobacillus brevis analyzed harbour both AgDI and tdc genes and are tyramine and putrescine producers. Conversely, among the other LAB tested, only one Lactobacillus hilgardii and one Pediococcus pentosaceus produced putrescine. The AgDI gene was also detected in two other LAB (Lactobacillus mali and Pediococcus parvulus), but no putrescine production was observed. Finally, hdc gene and histamine production were found in strains (L. hilgardii 5211, isolated from wine, and Lactobacillus casei 18, isolated from cider) that were not putrescine producers. PMID:23685467

  19. Protein and Amino Acid Restriction, Aging and Disease: from yeast to humans

    PubMed Central

    Mirzaei, Hamed; Suarez, Jorge A.; Longo, Valter D.

    2014-01-01

    Many of the effects of dietary restriction (DR) on longevity and health span in model organisms have been linked to reduced protein and amino acid (AA) intake and the stimulation of specific nutrient signaling pathways. Studies in yeast have shown that addition of serine, threonine, and valine in media promotes cellular sensitization and aging by activating different but connected pathways. Protein or essential AA restriction extends both lifespan and healthspan in rodent models. In humans, protein restriction (PR) has been associated with reduced cancer, diabetes, and overall mortality. Thus, interventions aimed at lowering the intake of proteins or specific AAs can be beneficial and have the potential to be widely adopted and effective in optimizing healthspan. PMID:25153840

  20. S-Adenosyl-L-Methionine protects the probiotic yeast, Saccharomyces boulardii, from acid-induced cell death

    PubMed Central

    2013-01-01

    Background Saccharomyces boulardii is a probiotic yeast routinely used to prevent and to treat gastrointestinal disorders, including the antibiotic-associated diarrhea caused by Clostridium difficile infections. However, only 1-3% of the yeast administered orally is recovered alive in the feces suggesting that this yeast is unable to survive the acidic environment of the gastrointestinal tract. Results We provide evidence that suggests that S. boulardii undergoes programmed cell death (PCD) in acidic environments, which is accompanied by the generation of reactive oxygen species and the appearance of caspase-like activity. To better understand the mechanism of cell death at the molecular level, we generated microarray gene expression profiles of S. boulardii cells cultured in an acidic environment. Significantly, functional annotation revealed that the up-regulated genes were significantly over-represented in cell death pathways Finally, we show that S-adenosyl-L-methionine (AdoMet), a commercially available, FDA-approved dietary supplement, enhances the viability of S. boulardii in acidic environments, most likely by preventing programmed cell death. Conclusions In toto, given the observation that many of the proven health benefits of S. boulardii are dependent on cell viability, our data suggests that taking S. boulardii and AdoMet together may be a more effective treatment for gastrointestinal disorders than taking the probiotic yeast alone. PMID:23402325

  1. Effects of organic acid treatments on small hive beetles, Aethina tumida, and the associated yeast Kodamaea ohmeri.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In honey bees, Apis mellifera, colonies infested with larval and adult small hive beetles (=SHB), hive materials and in particular honey tends to ferment due to the SHB associated yeast Kodamaea ohmeri. Here we test the effects of organic acids used by beekeepers to control other pests on SHB and K...

  2. Draft Genome Sequence of Cutaneotrichosporon curvatus DSM 101032 (Formerly Cryptococcus curvatus), an Oleaginous Yeast Producing Polyunsaturated Fatty Acids.

    PubMed

    Hofmeyer, Thomas; Hackenschmidt, Silke; Nadler, Florian; Thürmer, Andrea; Daniel, Rolf; Kabisch, Johannes

    2016-01-01

    Cutaneotrichosporon curvatus DSM 101032 is an oleaginous yeast that can be isolated from various habitats and is capable of producing substantial amounts of polyunsaturated fatty acids. Here, we present the first draft genome sequence of any C. curvatus species. PMID:27174275

  3. Draft Genome Sequence of Cutaneotrichosporon curvatus DSM 101032 (Formerly Cryptococcus curvatus), an Oleaginous Yeast Producing Polyunsaturated Fatty Acids

    PubMed Central

    Hofmeyer, Thomas; Hackenschmidt, Silke; Nadler, Florian; Thürmer, Andrea; Daniel, Rolf

    2016-01-01

    Cutaneotrichosporon curvatus DSM 101032 is an oleaginous yeast that can be isolated from various habitats and is capable of producing substantial amounts of polyunsaturated fatty acids. Here, we present the first draft genome sequence of any C. curvatus species. PMID:27174275

  4. Hydrothermal treatment of oleaginous yeast for the recovery of free fatty acids for use in advanced biofuel production.

    PubMed

    Espinosa-Gonzalez, Isabel; Parashar, Archana; Bressler, David C

    2014-10-10

    Microbial oils hold great potential as a suitable feedstock for the renewable production of biofuels. Specifically, the use of oleaginous yeasts offers several advantages related to cultivation and quality of lipid products. However, one of the major bottlenecks for large-scale production of yeast oils is found in the lipid extraction process. This work investigated the hydrothermal treatment of oleaginous yeast for hydrolysis and lipid extraction resulting in fatty acids used for biofuel production. The oleaginous yeast, Cryptococcus curvatus, was grown in 5 L bioreactors and the biomass slurry with 53±4% lipid content (dry weight basis) was treated at 280 °C for 1h with an initial pressure of 500 psi in batch stainless steel reactors. The hydrolysis product was separated and each of the resulting streams was further characterized. The hexane soluble fraction contained fatty acids from the hydrolysis of yeast triacylglycerides, and was low in nitrogen and minerals and could be directly integrated as feedstock into pyrolysis processing to produce biofuels. The proposed hydrothermal treatment addresses some current technological bottlenecks associated with traditional methodologies such as dewatering, oil extraction and co-product utilization. It also enhances the feasibility of using microbial biomass for production of renewable fuels and chemicals. PMID:25034431

  5. Transcriptional and antioxidative responses to endogenous polyunsaturated fatty acid accumulation in yeast.

    PubMed

    Andrisic, Luka; Collinson, Emma J; Tehlivets, Oksana; Perak, Eleonora; Zarkovic, Tomislav; Dawes, Ian W; Zarkovic, Neven; Cipak Gasparovic, Ana

    2015-01-01

    Pathophysiology of polyunsaturated fatty acids (PUFAs) is associated with aberrant lipid and oxygen metabolism. In particular, under oxidative stress, PUFAs are prone to autocatalytic degradation via peroxidation, leading to formation of reactive aldehydes with numerous potentially harmful effects. However, the pathological and compensatory mechanisms induced by lipid peroxidation are very complex and not sufficiently understood. In our study, we have used yeast capable of endogenous PUFA synthesis in order to understand the effects triggered by PUFA accumulation on cellular physiology of a eukaryotic organism. The mechanisms induced by PUFA accumulation in S. cerevisiae expressing Hevea brasiliensis Δ12-fatty acid desaturase include down-regulation of components of electron transport chain in mitochondria as well as up-regulation of pentose-phosphate pathway and fatty acid β-oxidation at the transcriptional level. Interestingly, while no changes were observed at the transcriptional level, activities of two important enzymatic antioxidants, catalase and glutathione-S-transferase, were altered in response to PUFA accumulation. Increased intracellular glutathione levels further suggest an endogenous oxidative stress and activation of antioxidative defense mechanisms under conditions of PUFA accumulation. Finally, our data suggest that PUFA in cell membrane causes metabolic changes which in turn lead to adaptation to endogenous oxidative stress. PMID:25280400

  6. Lactic acid-producing yeast cells having nonfunctional L- or D-lactate:ferricytochrome C oxidoreductase cells

    SciTech Connect

    Miller, Matthew; Suominen, Pirkko; Aristidou, Aristos; Hause, Benjamin Matthew; Van Hoek, Pim; Dundon, Catherine Asleson

    2012-03-20

    Yeast cells having an exogenous lactate dehydrogenase gene ae modified by reducing L- or D-lactate:ferricytochrome c oxidoreductase activity in the cell. This leads to reduced consumption of lactate by the cell and can increase overall lactate yields in a fermentation process. Cells having the reduced L- or D-lactate:ferricytochrome c oxidoreductase activity can be screened for by resistance to organic acids such as lactic or glycolic acid.

  7. Identification of uric acid as the redox molecule secreted by the yeast Arxula adeninivorans.

    PubMed

    Williams, Jonathan; Trautwein-Schult, Anke; Jankowska, Dagmara; Kunze, Gotthard; Squire, Marie A; Baronian, Keith

    2014-03-01

    The yeast Arxula adeninivorans has been previously shown to secrete a large amount of an electro-active molecule. The molecule was produced by cells that had been cultivated in a rich medium, harvested, washed and then suspended in phosphate-buffered saline (PBS). The molecule was easily detectable after 60 min of incubation in PBS, and the cells continued to produce the molecule in these conditions for up to 3 days. The peak anodic potential of the oxidation peak was 0.42 V, and it was shown to be a solution species rather than a cell-attached species. We have optimised the production of the molecule, identified it by high-pressure liquid chromatography (HPLC) fractionation and high-resolution mass spectrometric analysis and determined the pathway involved in its synthesis. It has a mass/charge ratio that corresponds to uric acid, and this identification was supported by comparing UV spectra and cyclic voltammograms of the samples to those of uric acid. An A. adeninivorans xanthine oxidase gene disruption mutant failed to produce uric acid, which added further validity to this identification. It also demonstrated that the purine catabolism pathway is involved in its production. A transgenic A. adeninivorans strain with a switchable urate oxidase gene (AUOX) accumulated uric acid when the gene was switched off but did not when the gene was switched on. Cultivation of cells on amino acid and purine-free minimal media with an inorganic nitrogen source suggests that the cells synthesise purines from inorganic nitrogen and proceed to degrade them via the normal purine degradation pathway. PMID:24407453

  8. Synthesis of the cancer preventive peptide lunasin by lactic acid bacteria during sourdough fermentation.

    PubMed

    Rizzello, Carlo G; Nionelli, Luana; Coda, Rossana; Gobbetti, Marco

    2012-01-01

    This study aimed to exploit the potential of sourdough lactic acid bacteria to release lunasin during fermentation of cereal and nonconventional flours. The peptidase activities of a large number of sourdough lactic acid bacteria were screened using synthetic substrates. Selected lactic acid bacteria were used as sourdough starters to ferment wholemeal wheat, soybean, barley, amaranth, and rye flours. Proteinase activity during fermentation was characterized by SDS-PAGE analysis of the water-soluble extracts. Albumins having molecular masses of 18 to 22 kDa, which included the size of lunasin precursors, were markedly affected by proteolysis of lactic acid bacteria. After fermentation, lunasin from the water-soluble extracts was quantified, purified, and identified through RP-HPLC and nano-LC-ESI-MS analyses. Compared to control doughs, the concentration of lunasin increased up to 2-4 times during fermentation. Lactobacillus curvatus SAL33 and Lactobacillus brevis AM7 synthesized the highest concentrations of lunasin in all the flours. Besides the presence of the entire lunasin sequence, fragments containing the immunoreactive epitope RGDDDDDDDDD were also found. This study shows that fermentation by lactic acid bacteria increased the concentration of lunasin to levels that would suggest new possibilities for the biological synthesis and for the formulation of functional foods. PMID:22098174

  9. Isolation and characterization of a gene specific to lager brewing yeast that encodes a branched-chain amino acid permease.

    PubMed

    Kodama, Y; Omura, F; Ashikari, T

    2001-08-01

    We found two types of branched-chain amino acid permease gene (BAP2) in the lager brewing yeast Saccharomyces pastorianus BH-225 and cloned one type of BAP2 gene (Lg-BAP2), which is identical to that of Saccharomyces bayanus (by-BAP2-1). The other BAP2 gene of the lager brewing yeast (cer-BAP2) is very similar to the Saccharomyces cerevisiae BAP2 gene. This result substantiates the notion that lager brewing yeast is a hybrid of S. cerevisiae and S. bayanus. The amino acid sequence homology between S. cerevisiae Bap2p and Lg-Bap2p was 88%. The transcription of Lg-BAP2 was not induced by the addition of leucine to the growth medium, while that of cer-BAP2 was induced. The transcription of Lg-BAP2 was repressed by the presence of ethanol and weak organic acid, while that of cer-BAP2 was not affected by these compounds. Furthermore, Northern analysis during beer fermentation revealed that the transcription of Lg-BAP2 was repressed at the beginning of the fermentation, while cer-BAP2 was highly expressed throughout the fermentation. These results suggest that the transcription of Lg-BAP2 is regulated differently from that of cer-BAP2 in lager brewing yeasts. PMID:11472919

  10. Selective suppression of bacterial contaminants by process conditions during lignocellulose based yeast fermentations

    PubMed Central

    2011-01-01

    Background Contamination of bacteria in large-scale yeast fermentations is a serious problem and a threat to the development of successful biofuel production plants. Huge research efforts have been spent in order to solve this problem, but additional ways must still be found to keep bacterial contaminants from thriving in these environments. The aim of this project was to develop process conditions that would inhibit bacterial growth while giving yeast a competitive advantage. Results Lactic acid bacteria are usually considered to be the most common contaminants in industrial yeast fermentations. Our observations support this view but also suggest that acetic acid bacteria, although not so numerous, could be a much more problematic obstacle to overcome. Acetic acid bacteria showed a capacity to drastically reduce the viability of yeast. In addition, they consumed the previously formed ethanol. Lactic acid bacteria did not show this detrimental effect on yeast viability. It was possible to combat both types of bacteria by a combined addition of NaCl and ethanol to the wood hydrolysate medium used. As a result of NaCl + ethanol additions the amount of viable bacteria decreased and yeast viability was enhanced concomitantly with an increase in ethanol concentration. The successful result obtained via addition of NaCl and ethanol was also confirmed in a real industrial ethanol production plant with its natural inherent yeast/bacterial community. Conclusions It is possible to reduce the number of bacteria and offer a selective advantage to yeast by a combined addition of NaCl and ethanol when cultivated in lignocellulosic medium such as wood hydrolysate. However, for optimal results, the concentrations of NaCl + ethanol must be adjusted to suit the challenges offered by each hydrolysate. PMID:22185398

  11. HYDROLYTIC BREAKDOWN OF LACTOFERRICIN BY LACTIC ACID BACTERIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactoferricin is a 25 amino acid antimicrobial peptide domain that is liberated by pepsin digestion of lactoferrin in bovine milk. Along with its antibacterial properties, lactoferricin has also been reported to have immunostimulatory, antiviral, and anticarcinogenic effects. There is substantial ...

  12. Ribonuclease "XlaI," an activity from Xenopus laevis oocytes that excises intervening sequences from yeast transfer ribonucleic acid precursors.

    PubMed Central

    Otsuka, A; de Paolis, A; Tocchini-Valentini, G P

    1981-01-01

    A ribonuclease (RNase) activity, RNase "XlaI," responsible for the excision of intervening sequences from two yeast transfer ribonucleic acid (tRNA) precursors, pre-tRNA(Tyr) and pre-tRNA(3Leu), has been purified 54-fold from nuclear extracts of Xenopus laevis oocytes. The RNase preparation is essentially free of contaminating RNase. A quantitative assay for RNase XlaI was developed, and the reaction products were characterized. RNase XlaI cleavage sites in the yeast tRNA precursors were identical to those made by yeast extracts (including 3'-phosphate and 5'-hydroxyl termini). Cleavage of pre-tRNA(3Leu) by RNase XlaI and subsequent ligation of the half-tRNA molecules do not require removal of the 5' leader or 3' trailer sequences. Images PMID:6765601

  13. Bacteriophages of lactic acid bacteria and their impact on milk fermentations.

    PubMed

    Garneau, Josiane E; Moineau, Sylvain

    2011-08-30

    Every biotechnology process that relies on the use of bacteria to make a product or to overproduce a molecule may, at some time, struggle with the presence of virulent phages. For example, phages are the primary cause of fermentation failure in the milk transformation industry. This review focuses on the recent scientific advances in the field of lactic acid bacteria phage research. Three specific topics, namely, the sources of contamination, the detection methods and the control procedures will be discussed. PMID:21995802

  14. Yeast Coq9 controls deamination of coenzyme Q intermediates that derive from para-aminobenzoic acid.

    PubMed

    He, Cuiwen H; Black, Dylan S; Nguyen, Theresa P T; Wang, Charles; Srinivasan, Chandra; Clarke, Catherine F

    2015-09-01

    Coq9 is a polypeptide subunit in a mitochondrial multi-subunit complex, termed the CoQ-synthome, required for biosynthesis of coenzyme Q (ubiquinone or Q). Deletion of COQ9 results in dissociation of the CoQ-synthome, but over-expression of Coq8 putative kinase stabilizes the CoQ-synthome in the coq9 null mutant and leads to the accumulation of two nitrogen-containing Q intermediates, imino-demethoxy-Q6 (IDMQ6) and 3-hexaprenyl-4-aminophenol (4-AP) when para-aminobenzoic acid (pABA) is provided as a ring precursor. To investigate whether Coq9 is responsible for deamination steps in Q biosynthesis, we utilized the yeast coq5-5 point mutant. The yeast coq5-5 point mutant is defective in the C-methyltransferase step of Q biosynthesis but retains normal steady-state levels of the Coq5 polypeptide. Here, we show that when high amounts of 13C6-pABA are provided, the coq5-5 mutant accumulates both 13C6-imino-demethyl-demethoxy-Q6 (13C6-IDDMQ6) and 13C6-demethyl-demethoxy-Q6 (13C6-DDMQ6). Deletion of COQ9 in the yeast coq5-5 mutant along with Coq8 over-expression and 13C6- pABA labeling leads to the absence of 13C6-DDMQ6, and the nitrogen-containing intermediates 13C6-4-AP and 13C6-IDDMQ6 persist. We describe a coq9 temperature-sensitive mutant and show that at the non-permissive temperature, steady-state polypeptide levels of Coq9-ts19 increased, while Coq4, Coq5, Coq6, and Coq7 decreased. The coq9-ts19 mutant had decreased Q6 content and increased levels of nitrogen-containing intermediates. These findings identify Coq9 as a multi-functional protein that is required for the function of Coq6 and Coq7 hydroxylases, for removal of the nitrogen substituent from pABA-derived Q intermediates, and is an essential component of the CoQ synthome. PMID:26008578

  15. Expression cloning in yeast of a cDNA encoding a broad specificity amino acid permease from Arabidopsis thaliana.

    PubMed Central

    Frommer, W B; Hummel, S; Riesmeier, J W

    1993-01-01

    To study amino acid transport in plants at the molecular level, we have isolated an amino acid permease cDNA from Arabidopsis thaliana by complementation of a yeast mutant defective in proline uptake with a cDNA. The predicted polypeptide of 53 kDa is highly hydrophobic with 12 putative membrane-spanning regions and shows no significant homologies to other known transporters. Expression of the cDNA enables the yeast mutant to take up L-[14C]proline. Competition studies argue for a broad but stereospecific substrate recognition by the permease, which resembles neutral or general amino acid transport systems from Chlorella and higher plants. Both pH dependence and inhibition by protonophores are consistent with a proton symport mechanism. Images Fig. 1 PMID:8327465

  16. FTIR microspectroscopy for rapid screening and monitoring of polyunsaturated fatty acid production in commercially valuable marine yeasts and protists.

    PubMed

    Vongsvivut, Jitraporn; Heraud, Philip; Gupta, Adarsha; Puri, Munish; McNaughton, Don; Barrow, Colin J

    2013-10-21

    The increase in polyunsaturated fatty acid (PUFA) consumption has prompted research into alternative resources other than fish oil. In this study, a new approach based on focal-plane-array Fourier transform infrared (FPA-FTIR) microspectroscopy and multivariate data analysis was developed for the characterisation of some marine microorganisms. Cell and lipid compositions in lipid-rich marine yeasts collected from the Australian coast were characterised in comparison to a commercially available PUFA-producing marine fungoid protist, thraustochytrid. Multivariate classification methods provided good discriminative accuracy evidenced from (i) separation of the yeasts from thraustochytrids and distinct spectral clusters among the yeasts that conformed well to their biological identities, and (ii) correct classification of yeasts from a totally independent set using cross-validation testing. The findings further indicated additional capability of the developed FPA-FTIR methodology, when combined with partial least squares regression (PLSR) analysis, for rapid monitoring of lipid production in one of the yeasts during the growth period, which was achieved at a high accuracy compared to the results obtained from the traditional lipid analysis based on gas chromatography. The developed FTIR-based approach when coupled to programmable withdrawal devices and a cytocentrifugation module would have strong potential as a novel online monitoring technology suited for bioprocessing applications and large-scale production. PMID:23957051

  17. Effect of Wheat Dietary Fiber Particle Size during Digestion In Vitro on Bile Acid, Faecal Bacteria and Short-Chain Fatty Acid Content.

    PubMed

    Dziedzic, Krzysztof; Szwengiel, Artur; Górecka, Danuta; Gujska, Elżbieta; Kaczkowska, Joanna; Drożdżyńska, Agnieszka; Walkowiak, Jarosław

    2016-06-01

    The influence of bile acid concentration on the growth of Bifidobacterium spp. and Lactobacillus spp. bacteria was demonstrated. Exposing these bacteria to the environment containing bile acid salts, and very poor in nutrients, leads to the disappearance of these microorganisms due to the toxic effect of bile acids. A multidimensional analysis of data in the form of principal component analysis indicated that lactic acid bacteria bind bile acids and show antagonistic effect on E. coli spp. bacteria. The growth in E. coli spp. population was accompanied by a decline in the population of Bifidobacterium spp. and Lactobacillus spp. with a simultaneous reduction in the concentration of bile acids. This is direct proof of acid binding ability of the tested lactic acid bacteria with respect to cholic acid, lithocholic acid and deoxycholic acid. This research demonstrated that the degree of fineness of wheat dietary fibre does not affect the sorption of bile acids and growth of some bacteria species; however, it has an impact on the profile of synthesized short-chained fatty acids. During the digestion of a very fine wheat fibre fraction (WF 90), an increase in the concentration of propionic and butyric acids, as compared with the wheat fiber fraction of larger particles - WF 500, was observed. Our study suggested that wheat fibre did not affect faecal bacteria growth, however, we observed binding of bile acids by Bifidobacterium spp. and Lactobacillus spp. PMID:26924312

  18. The N-acetylcysteine-insensitive acetic acid-induced yeast programmed cell death occurs without macroautophagy.

    PubMed

    Antonacci, Lucia; Guaragnella, Nicoletta; Ždralevic, Maša; Passarella, Salvatore; Marra, Ersilia; Giannattasio, Sergio

    2012-12-01

    Programmed cell death can occur through two separate pathways caused by treatment of Saccharomyces cerevisiae with acetic acid (AA-PCD), which differ from one another essentially with respect to their sensitivity to N-acetylcysteine (NAC) and to the role played by cytochrome c and metacaspase YCA1. Moreover, yeast can also undergo macroautophagy which occurs in NAC-insensitive manner. In order to gain some insight into the relationship between AA-PCD and macroautophagy use was made of WT and knock-out cells lacking YCA1 and/or cytochrome c. We show that i. macroautophagy is modulated by YCA1 and by cytochrome c in a negative and positive manner, respectively, ii. the NAC-insensitive AA-PCD and macroautophagy differ from one another and iii. NAC-insensitive AA-PCD pathway takes place essentially without macroautophagy, even if the shift of extracellular pH to acidic values required for AA-PCD to occur leads itself to increased or decreased macroautophagy in YCA1 or cytochrome c-lacking cells. PMID:23072389

  19. Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

    PubMed

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

    2014-12-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. PMID:25261518

  20. Hydroxycinnamic Acids Used as External Acceptors of Electrons: an Energetic Advantage for Strictly Heterofermentative Lactic Acid Bacteria

    PubMed Central

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria

    2014-01-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD+/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD+/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. PMID:25261518

  1. Cancer Preventive Potential of Kimchi Lactic Acid Bacteria (Weissella cibaria, Lactobacillus plantarum)

    PubMed Central

    Kwak, Shin-Hye; Cho, Young-Mi; Noh, Geon-Min; Om, Ae-Son

    2014-01-01

    The number of death due to cancer has been increasing in Korea. Chemotherapy is known to cause side effects because it damages not only cancerous cells but healthy cells. Recently, attention has focused on food-derived chemopreventive and anti-tumor agents or formulations with fewer side effects. Kimchi, most popular and widely consumed in Korea, contains high levels of lactic acid bacteria and has been shown to possess chemopreventive effects. This review focuses on Weissella cibaria and Lactobacillus plantarum, the representatives of kimchi lactic acid bacteria, in terms of their abilities to prevent cancer. Further studies are needed to understand the mechanisms by which lactic acid bacteria in kimchi prevent carcinogenic processes and improve immune functions. PMID:25574459

  2. Phenotypic and genotypic characterization of lactic acid bacteria isolated from raw goat milk and effect of farming practices on the dominant species of lactic acid bacteria.

    PubMed

    Tormo, Hélène; Ali Haimoud Lekhal, Djamila; Roques, C

    2015-10-01

    Lactic acid bacteria, in particular Lactococcus lactis, play a decisive role in the cheese making process and more particularly in lactic cheeses which are primarily produced on goat dairy farms. The objective of this study was therefore to identify the main lactic acid bacteria found in raw goats' milk from three different regions in France and evaluate if certain farming practices have an effect on the distribution of species of lactic acid bacteria in the various milk samples. Identification at genus or species level was carried out using phenotypic tests and genotypic methods including repetitive element REP-PCR, species-specific PCR and 16S rRNA gene sequencing. The distribution of the main bacterial species in the milk samples varied depending on farms and their characteristics. Out of the 146 strains identified, L. lactis was the dominant species (60% of strains), followed by Enterococcus (38%) of which Enterococcus faecalis and Enterococcus faecium. Within the species L. lactis, L. lactis subsp lactis was detected more frequently than L. lactis subsp cremoris (74% vs. 26%). The predominance of L. lactis subsp cremoris was linked to geographical area studied. It appears that the animals' environment plays a role in the balance between the dominance of L. lactis and enterococci in raw goats' milk. The separation between the milking parlor and the goat shed (vs no separation) and only straw in the bedding (vs straw and hay) seems to promote L. lactis in the milk (vs enterococci). PMID:26082325

  3. Production of Antilisterial Bacteriocins from Lactic Acid Bacteria in Dairy-Based Media: A Comparative Study.

    PubMed

    Ünlü, Gülhan; Nielsen, Barbara; Ionita, Claudia

    2015-12-01

    One hundred and eight strains of lactic acid bacteria (LAB) were screened for bacteriocin production by the modified deferred antagonism and agar well diffusion methods. When the modified deferred antagonism method was employed, 82 LAB strains showed inhibitory action against Listeria monocytogenes v7 ½a, whereas 26 LAB strains expressed no inhibition. Only 12 LAB strains exhibited inhibitory activity when the agar well diffusion method was used, 11 of which had been previously recognized as bacteriocin production positive (Bac(+)). Lactobacillus viridescens NRRL B-1951 was determined, for the first time, to produce an inhibitory compound with a proteinaceous nature. The inhibitory activity was observed in the presence of lipase, α-chymotrypsin, and trypsin, but no inhibition zone could be detected in the presence of proteinase K, indicating the proteinaceous nature of the inhibitory compound. The inhibitory compound was active against Lact. sake ATCC 15521 and Lact. plantarum NCDO 995. Bacteriocin production by the Bac(+) LAB strains was assessed in Lactobacillus MRS Broth as well as in dairy-based media such as nonfat milk, demineralized whey powder, and cheddar cheese whey supplemented with complex nutrient sources that are rich in nitrogen. Lact. sake ATCC 15521 and L. monocytogenes CWD 1002, CWD 1092, CWD 1157, CWD 1198, and v7 ½a were used as indicators. The inhibitory activities of the bacteriocins varied depending on the indicator strains and the growth media used. The LAB indicator strains were found to be more sensitive to inhibition by bacteriocins when compared to the listerial indicator strains. Among the listerial indicators, L. monocytogenes CWD 1002 and CWD 1198 were the most sensitive strains to the bacteriocins investigated in this study. Media composition had a significant influence on bacteriocin production and activity. When compared to demineralized whey powder medium and cheddar cheese whey medium supplemented with whey protein concentrate

  4. [Comparative genomics and evolutionary analysis of CRISPR loci in acetic acid bacteria].

    PubMed

    Kai, Xia; Xinle, Liang; Yudong, Li

    2015-12-01

    The clustered regularly interspaced short palindromic repeat (CRISPR) is a widespread adaptive immunity system that exists in most archaea and many bacteria against foreign DNA, such as phages, viruses and plasmids. In general, CRISPR system consists of direct repeat, leader, spacer and CRISPR-associated sequences. Acetic acid bacteria (AAB) play an important role in industrial fermentation of vinegar and bioelectrochemistry. To investigate the polymorphism and evolution pattern of CRISPR loci in acetic acid bacteria, bioinformatic analyses were performed on 48 species from three main genera (Acetobacter, Gluconacetobacter and Gluconobacter) with whole genome sequences available from the NCBI database. The results showed that the CRISPR system existed in 32 species of the 48 strains studied. Most of the CRISPR-Cas system in AAB belonged to type I CRISPR-Cas system (subtype E and C), but type II CRISPR-Cas system which contain cas9 gene was only found in the genus Acetobacter and Gluconacetobacter. The repeat sequences of some CRISPR were highly conserved among species from different genera, and the leader sequences of some CRISPR possessed conservative motif, which was associated with regulated promoters. Moreover, phylogenetic analysis of cas1 demonstrated that they were suitable for classification of species. The conservation of cas1 genes was associated with that of repeat sequences among different strains, suggesting they were subjected to similar functional constraints. Moreover, the number of spacer was positively correlated with the number of prophages and insertion sequences, indicating the acetic acid bacteria were continually invaded by new foreign DNA. The comparative analysis of CRISR loci in acetic acid bacteria provided the basis for investigating the molecular mechanism of different acetic acid tolerance and genome stability in acetic acid bacteria. PMID:26704949

  5. 10-oxo-12(Z)-octadecenoic acid, a linoleic acid metabolite produced by gut lactic acid bacteria, potently activates PPARγ and stimulates adipogenesis

    SciTech Connect

    Goto, Tsuyoshi; Kim, Young-Il; Furuzono, Tomoya; Takahashi, Nobuyuki; Yamakuni, Kanae; Yang, Ha-Eun; Li, Yongjia; Ohue, Ryuji; Nomura, Wataru; Sugawara, Tatsuya; Yu, Rina; Kitamura, Nahoko; and others

    2015-04-17

    Our previous study has shown that gut lactic acid bacteria generate various kinds of fatty acids from polyunsaturated fatty acids such as linoleic acid (LA). In this study, we investigated the effects of LA and LA-derived fatty acids on the activation of peroxisome proliferator-activated receptors (PPARs) which regulate whole-body energy metabolism. None of the fatty acids activated PPARδ, whereas almost all activated PPARα in luciferase assays. Two fatty acids potently activated PPARγ, a master regulator of adipocyte differentiation, with 10-oxo-12(Z)-octadecenoic acid (KetoA) having the most potency. In 3T3-L1 cells, KetoA induced adipocyte differentiation via the activation of PPARγ, and increased adiponectin production and insulin-stimulated glucose uptake. These findings suggest that fatty acids, including KetoA, generated in gut by lactic acid bacteria may be involved in the regulation of host energy metabolism. - Highlights: • Most LA-derived fatty acids from gut lactic acid bacteria potently activated PPARα. • Among tested fatty acids, KetoA and KetoC significantly activated PPARγ. • KetoA induced adipocyte differentiation via the activation of PPARγ. • KetoA enhanced adiponectin production and glucose uptake during adipogenesis.

  6. Study of the Ecology of Fresh Sausages and Characterization of Populations of Lactic Acid Bacteria by Molecular Methods

    PubMed Central

    Cocolin, Luca; Rantsiou, Kalliopi; Iacumin, Lucilla; Urso, Rosalinda; Cantoni, Carlo; Comi, Giuseppe

    2004-01-01

    In this study, a polyphasic approach was used to study the ecology of fresh sausages and to characterize populations of lactic acid bacteria (LAB). The microbial profile of fresh sausages was monitored from the production day to the 10th day of storage at 4°C. Samples were collected on days 0, 3, 6, and 10, and culture-dependent and -independent methods of detection and identification were applied. Traditional plating and isolation of LAB strains, which were subsequently identified by molecular methods, and the application of PCR-denaturing gradient gel electrophoresis (DGGE) to DNA and RNA extracted directly from the fresh sausage samples allowed the study in detail of the changes in the bacterial and yeast populations during storage. Brochothrix thermosphacta and Lactobacillus sakei were the main populations present. In particular, B. thermosphacta was present throughout the process, as determined by both DNA and RNA analysis. Other bacterial species, mainly Staphylococcus xylosus, Leuconostoc mesenteroides, and L. curvatus, were detected by DGGE. Moreover, an uncultured bacterium and an uncultured Staphylococcus sp. were present, too. LAB strains isolated at day 0 were identified as Lactococcus lactis subsp. lactis, L. casei, and Enterococcus casseliflavus, and on day 3 a strain of Leuconostoc mesenteroides was identified. The remaining strains isolated belonged to L. sakei. Concerning the yeast ecology, only Debaryomyces hansenii was established in the fresh sausages. Capronia mansonii was initially present, but it was not detected after the first 3 days. At last, L. sakei isolates were characterized by randomly amplified polymorphic DNA PCR and repetitive DNA element PCR. The results obtained underlined how different populations took over at different steps of the process. This is believed to be the result of the selection of the particular population, possibly due to the low storage temperature employed. PMID:15066777

  7. Plasmids from Food Lactic Acid Bacteria: Diversity, Similarity, and New Developments

    PubMed Central

    Cui, Yanhua; Hu, Tong; Qu, Xiaojun; Zhang, Lanwei; Ding, Zhongqing; Dong, Aijun

    2015-01-01

    Plasmids are widely distributed in different sources of lactic acid bacteria (LAB) as self-replicating extrachromosomal genetic materials, and have received considerable attention due to their close relationship with many important functions as well as some industrially relevant characteristics of the LAB species. They are interesting with regard to the development of food-grade cloning vectors. This review summarizes new developments in the area of lactic acid bacteria plasmids and aims to provide up to date information that can be used in related future research. PMID:26068451

  8. A combination of two lactic acid bacteria improves the hydrolysis of gliadin during wheat dough fermentation.

    PubMed

    Gerez, Carla Luciana; Dallagnol, Andrea; Rollán, Graciela; Font de Valdez, Graciela

    2012-12-01

    The evaluation of gliadin hydrolysis during dough fermentation by using two lactic acid bacteria, Lactobacillus plantarum CRL 775 and Pediococcus pentosaceus CRL 792, as pooled cell suspension (LAB) or cell free extract (CFE) was undertaken. The CFE pool produced a greater (121%) increase in amino acid concentration than the LAB pool (70-80%). These results were correlated with the decrease (76,100 and 64,300 ppm) in the gliadin concentration of doughs supplemented with CFE and LAB, respectively, compared to control doughs. The use of LAB peptidases seemed to be a viable technologic alternative to reduce the gliadin concentration in wheat dough without using living bacteria as starter. PMID:22986210

  9. Acetic Acid Bacteria and the Production and Quality of Wine Vinegar

    PubMed Central

    Torija, María Jesús; García-Parrilla, María del Carmen; Troncoso, Ana María

    2014-01-01

    The production of vinegar depends on an oxidation process that is mainly performed by acetic acid bacteria. Despite the different methods of vinegar production (more or less designated as either “fast” or “traditional”), the use of pure starter cultures remains far from being a reality. Uncontrolled mixed cultures are normally used, but this review proposes the use of controlled mixed cultures. The acetic acid bacteria species determine the quality of vinegar, although the final quality is a combined result of technological process, wood contact, and aging. This discussion centers on wine vinegar and evaluates the effects of these different processes on its chemical and sensory properties. PMID:24574887

  10. Effects of maturity stage and lactic acid bacteria on the fermentation quality and aerobic stability of Siberian wildrye silage.

    PubMed

    Li, Ping; Bai, Shiqie; You, Minghong; Shen, Yixin

    2016-09-01

    It is difficult to make good quality of silage from alpine gramineous from the Qinghai Tibetan plateau. The effects of lactic acid bacteria (LAB) on the fermentation quality and aerobic stability of Siberian wildrye silage were studied in southeast of the Qinghai Tibetan plateau. Siberian wildrye materials were freshly cut at the sprouting stage, flowering stage, and milky stage. Silage was prepared by using a small-scale silage fermentation system (bag silos). Lactobacillus plantarum (LP, 5 × 10(8) cfu/kg FM), Lactobacillus buchneri (LB, 5 × 10(8) cfu/kg FM) and their mixture (LP+LB, 5 × 10(8) cfu/kg FM) as silage additives were separately added to ensiled forages, and no additive served as control (CK). These bag silos were kept at room temperature (<15°C), and the silage qualities were analyzed after 60 days of ensiling. The number of indigenous LAB on fresh materials was less than that of yeasts and molds, and LAB species showed specification adapted to low temperature. LAB inoculated silages had lower (P < 0.05) pH value, NH 3-N/TN and butyric acid content compared with control silage. Silage treated with LB had higher contents of acetic acid, propionic acid, WSC and CP. However, the aerobic stability of silages inoculated with LAB did not differ significantly between stages (P > 0.05). When fermentation characteristics, chemical composition, and aerobic stability were considered, treatment with L. plantarum resulted in high quality of Siberian wildrye silage harvested at the flowering stage in the alpine region. PMID:27625768

  11. Lactic Acid Bateria - Friend or Foe? Lactic Acid Bacteria in the Production of Polysaccharides and Fuel Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactic acid bacteria (LAB) have been widely used in the production of fermented foods and as probiotics. Alternan is a glucan with a distinctive backbone structure of alternating alpha-(1,6) and alpha-(1,3) linkages produced by the LAB Leuconostoc mesenteroides. In recent years, improved strains f...

  12. Relationship between Sublethal Injury and Inactivation of Yeast Cells by the Combination of Sorbic Acid and Pulsed Electric Fields▿

    PubMed Central

    Somolinos, M.; García, D.; Condón, S.; Mañas, P.; Pagán, R.

    2007-01-01

    The objective of this study was to investigate the occurrence of sublethal injury after the pulsed-electric-field (PEF) treatment of two yeasts, Dekkera bruxellensis and Saccharomyces cerevisiae, as well as the relation of sublethal injury to the inactivating effect of the combination of PEF and sorbic acid. PEF caused sublethal injury in both yeasts: more than 90% of surviving D. bruxellensis cells and 99% of surviving S. cerevisiae cells were sublethally injured after 50 pulses at 12 kV/cm in buffer at pHs of both 7.0 and 4.0. The proportion of sublethally injured cells reached a maximum after 50 pulses at 12.0 kV/cm (S. cerevisiae) or 16.5 kV/cm (D. bruxellensis), and it kept constant or progressively decreased at greater electric field strengths and with longer PEF treatments. Sublethally PEF-injured cells showed sensitivity to the presence of sorbic acid at a concentration of 2,000 ppm. A synergistic inactivating effect of the combination of PEF and sorbic acid was observed. Survivors of the PEF treatment were progressively inactivated in the presence of 2,000 ppm of sorbic acid at pH 3.8, with the combined treatments achieving more than log10 5 cycles of dead cells under the conditions investigated. This study has demonstrated the occurrence of sublethal injury after exposure to PEF, so yeast inactivation by PEF is not an all-or-nothing event. The combination of PEF and sorbic acid has proven to be an effective method to achieve a higher level of yeast inactivation. This work contributes to the knowledge of the mechanism of microbial inactivation by PEF, and it may be useful for improving food preservation by PEF technology. PMID:17468278

  13. The Antifungal Eugenol Perturbs Dual Aromatic and Branched-Chain Amino Acid Permeases in the Cytoplasmic Membrane of Yeast

    PubMed Central

    Darvishi, Emad; Omidi, Mansoor; Bushehri, Ali Akbar Shahnejat; Golshani, Ashkan; Smith, Myron L.

    2013-01-01

    Eugenol is an aromatic component of clove oil that has therapeutic potential as an antifungal drug, although its mode of action and precise cellular target(s) remain ambiguous. To address this knowledge gap, a chemical-genetic profile analysis of eugenol was done using ∼4700 haploid Saccharomyces cerevisiae gene deletion mutants to reveal 21 deletion mutants with the greatest degree of susceptibility. Cellular roles of deleted genes in the most susceptible mutants indicate that the main targets for eugenol include pathways involved in biosynthesis and transport of aromatic and branched-chain amino acids. Follow-up analyses showed inhibitory effects of eugenol on amino acid permeases in the yeast cytoplasmic membrane. Furthermore, phenotypic suppression analysis revealed that eugenol interferes with two permeases, Tat1p and Gap1p, which are both involved in dual transport of aromatic and branched-chain amino acids through the yeast cytoplasmic membrane. Perturbation of cytoplasmic permeases represents a novel antifungal target and may explain previous observations that exposure to eugenol results in leakage of cell contents. Eugenol exposure may also contribute to amino acid starvation and thus holds promise as an anticancer therapeutic drug. Finally, this study provides further evidence of the usefulness of the yeast Gene Deletion Array approach in uncovering the mode of action of natural health products. PMID:24204588

  14. Local domestication of lactic acid bacteria via cassava beer fermentation

    PubMed Central

    Meadow, James F.; Liebert, Melissa A.; Cepon-Robins, Tara J.; Gildner, Theresa E.; Urlacher, Samuel S.; Bohannan, Brendan J.M.; Snodgrass, J. Josh; Sugiyama, Lawrence S.

    2014-01-01

    Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) is thought to improve nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes for the human microbiome, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples. Significantly greater phylogenetic similarity was observed among chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human-mediated factors, may be responsible for creating locally distinct ferments. Our results add to evidence from other fermentation systems suggesting that traditional fermentation may be a form of domestication, providing endemic beneficial inocula for consumers, but additional research is needed to identify the mechanisms and extent of microbial dispersal. PMID:25071997

  15. Local domestication of lactic acid bacteria via cassava beer fermentation.

    PubMed

    Colehour, Alese M; Meadow, James F; Liebert, Melissa A; Cepon-Robins, Tara J; Gildner, Theresa E; Urlacher, Samuel S; Bohannan, Brendan J M; Snodgrass, J Josh; Sugiyama, Lawrence S

    2014-01-01

    Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) is thought to improve nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes for the human microbiome, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples. Significantly greater phylogenetic similarity was observed among chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human-mediated factors, may be responsible for creating locally distinct ferments. Our results add to evidence from other fermentation systems suggesting that traditional fermentation may be a form of domestication, providing endemic beneficial inocula for consumers, but additional research is needed to identify the mechanisms and extent of microbial dispersal. PMID:25071997

  16. Diversity of culturable yeasts in phylloplane of sugarcane in Thailand and their capability to produce indole-3-acetic acid.

    PubMed

    Limtong, Savitree; Kaewwichian, Rungluk; Yongmanitchai, Wichien; Kawasaki, Hiroko

    2014-06-01

    Yeasts were isolated by the enrichment technique from the phylloplane of 94 samples of sugarcane leaf collected from seven provinces in Thailand. All sugarcane leaf samples contained yeasts and 158 yeast strains were obtained. On the basis of the D1/D2 domain of the large subunit rRNA gene sequence analysis, 144 strains were identified to 24 known species in 14 genera belonging to the Ascomycota viz. Candida akabanensis, Candida dendronema, Candida mesorugosa, Candida michaelii, Candida nivariensis, Candida rugosa, Candida orthopsilosis, Candida quercitrusa, Candida tropicalis, Candida xylopsoci, Cyberlindnera fabianii, Cyberlindnera rhodanensis, Debaryomyces nepalensis, Hannaella aff. coprosmaensis, Hanseniaspora guilliermondii, Kluyveromyces marxianus, Lachancea thermotolerans, Lodderomyces elongisporus, Metschnikowia koreensis, Meyerozyma caribbica, Millerozyma koratensis, Pichia kudriavzevii, Torulaspora delbrueckii and Wickerhamomyces edaphicus, and 12 species in six genera of the Basidiomycota viz . Cryptococcus flavescens, Cryptococcus laurentii, Cryptococcus rajasthanensis, Kwoniella heveanensis, Rhodosporidium fluviale, Rhodosporidium paludigenum, Rhodotorula mucilaginosa, Rhodotorula sesimbrana, Rhodotorula taiwanensis, Sporidiobolus ruineniae, Sporobolomyces carnicolor and Sporobolomyces nylandii. Seven strains were identical or similar to four undescribed species. Another seven strains represented four novels species in the genus Metschnikowia, Nakazawaea, Wickerhamomyces and Yamadazyma. The results revealed 69 % of the isolated strains were ascomycete yeasts and 31 % were basidiomycete yeast. The most prevalent species was M. caribbica with a 23 % frequency of occurrence followed by Rh. taiwanensis (11 %) and C. tropicalis (10 %). All strains were assessed for indole-3-acetic acid (IAA) producing capability showing that 69 strains had the capability of producing IAA when cultivated in yeast extract peptone dextrose broth supplemented with 1

  17. Sulfuric acid hydrolysis and detoxification of red alga Pterocladiella capillacea for bioethanol fermentation with thermotolerant yeast Kluyveromyces marxianus.

    PubMed

    Wu, Chien-Hui; Chien, Wei-Chen; Chou, Han-Kai; Yang, Jungwoo; Lin, Hong-Ting Victor

    2014-09-01

    One-step sulfuric acid saccharification of the red alga Pterocladiella capillacea was optimized, and various detoxification methods (neutralization, overliming, and electrodialysis) of the acid hydrolysate were evaluated for fermentation with the thermotolerant yeast Kluyveromyces marxianus. A proximate composition analysis indicated that P. capillacea was rich in carbohydrates. A significant galactose recovery of 81.1 ± 5% was also achieved under the conditions of a 12% (w/v) biomass load, 5% (v/v) sulfuric acid, 121°C, and hydrolysis for 30 min. Among the various detoxification methods, electrodialysis was identified as the most suitable for fermentable sugar recovery and organic acid removal (100% reduction of formic and levulinic acids), even though it failed to reduce the amount of the inhibitor 5-HMF. As a result, K. marxianus fermentation with the electrodialyzed acid hydrolysate of P. capillacea resulted in the best ethanol levels and fermentation efficiency. PMID:24851812

  18. Surviving the Acid Test: Responses of Gram-Positive Bacteria to Low pH

    PubMed Central

    Cotter, Paul D.; Hill, Colin

    2003-01-01

    Gram-positive bacteria possess a myriad of acid resistance systems that can help them to overcome the challenge posed by different acidic environments. In this review the most common mechanisms are described: i.e., the use of proton pumps, the protection or repair of macromolecules, cell membrane changes, production of alkali, induction of pathways by transcriptional regulators, alteration of metabolism, and the role of cell density and cell signaling. We also discuss the reponses of Listeria monocytogenes, Rhodococcus, Mycobacterium, Clostridium perfringens, Staphylococcus aureus, Bacillus cereus, oral streptococci, and lactic acid bacteria to acidic environments and outline ways in which this knowledge has been or may be used to either aid or prevent bacterial survival in low-pH environments. PMID:12966143

  19. Heterologous surface display on lactic acid bacteria: non-GMO alternative?

    PubMed Central

    Zadravec, Petra; Štrukelj, Borut; Berlec, Aleš

    2015-01-01

    Lactic acid bacteria (LAB) are food-grade hosts for surface display with potential applications in food and therapy. Alternative approaches to surface display on LAB would avoid the use of recombinant DNA technology and genetically-modified organism (GMO)-related regulatory requirements. Non-covalent surface display of proteins can be achieved by fusing them to various cell-wall binding domains, of which the Lysine motif domain (LysM) is particularly well studied. Fusion proteins have been isolated from recombinant bacteria or from their growth medium and displayed on unmodified bacteria, enabling heterologous surface display. This was demonstrated on non-viable cells devoid of protein content, termed bacteria-like particles, and on various species of genus Lactobacillus. Of the latter, Lactobacillus salivarius ATCC 11741 was recently shown to be particularly amenable for LysM-mediated display. Possible regulatory implications of heterologous surface display are discussed, particularly those relevant for the European Union. PMID:25880164

  20. [Susceptibility of spore-forming butyric acid bacteria to antimicrobial agents].

    PubMed

    Kaneko, Naofumi; Nakayama, Tomohiro; Ichikawa, Nobuhiro

    2012-01-01

    Antimicrobial agents occasionally cause certain adverse effects, such as diarrhea and loose stool, by altering the composition of the intestinal flora. Antibiotic-resistant lactic acid bacteria are used to prevent these adverse effects. Although these bacteria are not resistant to several recently introduced antimicrobial agents, bacterial preparations are still sometimes prescribed concomitantly with these antimicrobial agents. In this study, we investigated whether the administration of the spore-forming butyric acid bacteria Clostridium butyricum improves the adverse clinical effects by preventing diarrhea. Inhibition of C. butyricum growth was observed with 17 of the 20 antimicrobial agents used. However, dilution of 11 of these 17 agents resulted in the regrowth of C. butyricum. These results suggest that C. butyricum may survive exposure to several antibiotic agents by forming spores. Further, a decrease in the antimicrobial agent concentration in the gastrointestinal tract permits the vegetative growth of C. butyricum, which functions as a probiotic. PMID:22790032

  1. Comparison of the Morphology and Deoxyribonucleic Acid Composition of 27 Strains of Nitrifying Bacteria1

    PubMed Central

    Watson, Stanley W.; Mandel, Manley

    1971-01-01

    The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid GC compositions. Similarly, the nitrite-oxidizing bacteria were separated into three genera based on their morphology. The members of two of these nitrite-oxidizing genera, Nitrobacter and Nitrococcus, had similar GC compositions, but Nitrospina gracilis had a significantly lower GC composition than the members of the other two genera. Images PMID:4939767

  2. Short-chain fatty acids produced by intestinal bacteria.

    PubMed

    Topping, D L

    1996-03-01

    The colon is the major site of bacterial colonisation in the human gut and the resident species are predominantly anaerobes. They include potential pathogens but the greater proportion appear to be organisms which salvage energy through the metabolism of undigested carbohydrates and gut secretions. The major products of carbohydrate metabolism are the short chain fatty acids (SCFA), acetate, propionate and butyrate. In addition to general effects (such as lowering of pH) individual acids exert specific effects. All of the major SCFA appear to promote the flow of blood through the colonic vasculature while propionate enhances muscular activity and epithelial cell proliferation. Butyrate appears to promote a normal cell phenotype as well as being a major fuel for colonocytes. Important substrates for bacterial fermentation include non-starch polysaccharides (major components of dietary fibre) but it seems that starch which has escaped digestion in the small intestine (resistant starch) is the major contributor. Oligosaccharides are utilised by probiotic organisms and in the diet, act as prebiotics in promoting their numbers in faeces. High amylose starch is a form of RS and it appears to act as a prebiotic also. Although there is evidence that probiotics such as Bifidobacteria metabolise oligosaccharides and other carbohydrates, there appears to be little evidence to support a change in faecal SCFA excretion. It seems that any health benefits of probiotics are exerted through means other than SCFA. PMID:24394459

  3. Racemization in Reverse: Evidence that D-Amino Acid Toxicity on Earth Is Controlled by Bacteria with Racemases

    PubMed Central

    Zhang, Gaosen; Sun, Henry J.

    2014-01-01

    D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free. PMID:24647559

  4. Glucansucrases from lactic acid bacteria which produce water-insoluble polysaccharides from sucrose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dextrans and related glucans produced from sucrose by lactic acid bacteria have been studied for many years and are used in numerous commercial applications and products. Most of these glucans are water-soluble, except for a few notable exceptions from cariogenic Streptococcus spp. and a very small ...

  5. Bacteria and Archaea in acidic environments and a key to morphological identification

    USGS Publications Warehouse

    Robbins, E.I.

    2000-01-01

    Natural and anthropogenic acidic environments are dominated by bacteria and Archaea. As many as 86 genera or species have been identified or isolated from pH <4.5 environments. This paper reviews the worldwide literature and provide tables of morphological characteristics, habitat information and a key for light microscope identification for the non-microbiologist.

  6. Comparison of phenotypic and molecular tests to identify lactic acid bacteria

    PubMed Central

    Moraes, Paula Mendonça; Perin, Luana Martins; Júnior, Abelardo Silva; Nero, Luís Augusto

    2013-01-01

    Twenty-nine lactic acid bacteria (LAB) isolates were submitted for identification using Biolog, API50CHL, 16S rDNA sequencing, and species-specific PCR reactions. The identification results were compared, and it was concluded that a polyphasic approach is necessary for proper LAB identification, being the molecular analyzes the most reliable. PMID:24159291

  7. The Effects of Monensin on Amino Acid Catabolizing Bacteria Isolated from the Boer Goat Rumen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    When ruminants consume feed, as much as half of the amino acid nitrogen can be lost due to microbial degradation in the rumen. Hyper ammonia-producing bacteria (HAB) are primarily responsible for nitrogen loss in sheep and cattle, and these organisms have been well characterized. However, little is ...

  8. Mine Waste Technology Program. In Situ Source Control Of Acid Generation Using Sulfate-Reducing Bacteria

    EPA Science Inventory

    This report summarizes the results of the Mine Waste Technology Program (MWTP) Activity III, Project 3, In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S....

  9. Survival and Phospholipid Fatty Acid Profiles of Surface and Subsurface Bacteria in Natural Sediment Microcosms

    PubMed Central

    Kieft, T. L.; Wilch, E.; O'Connor, K.; Ringelberg, D. B.; White, D. C.

    1997-01-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P. fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. PMID:16535578

  10. Survival and phospholipid fatty acid profiles of surface and subsurface bacteria in natural sediment microcosms

    SciTech Connect

    Kieft, T.L.; Wilch, E.; O`Connor, K.

    1997-04-01

    Although starvation survival has been characterized for many bacteria, few subsurface bacteria have been tested, and few if any have been tested in natural subsurface porous media. We hypothesized that subsurface bacteria may be uniquely adapted for long-term survival in situ. We further hypothesized that subsurface conditions (sediment type and moisture content) would influence microbial survival. We compared starvation survival capabilities of surface and subsurface strains of Pseudomonas fluorescens and a novel Arthrobacter sp. in microcosms composed of natural sediments. Bacteria were incubated for up to 64 weeks under saturated and unsaturated conditions in sterilized microcosms containing either a silty sand paleosol (buried soil) or a sandy silt nonpaleosol sediment. Direct counts, plate counts, and cell sizes were measured. Membrane phospholipid fatty acid (PLFA) profiles were quantified to determine temporal patterns of PLFA stress signatures and differences in PLFAs among strains and treatments. The Arthrobacter strains survived better than the P. fluorescens strains; however, differences in survival between surface and subsurface strains of each genus were not significant. Bacteria survived better in the paleosol than in the nonpaleosol and survived better under saturated conditions than under unsaturated conditions. Cell volumes of all strains decreased; however, sediment type and moisture did not influence rates of miniaturization. Both P.fluorescens strains showed PLFA stress signatures typical for gram-negative bacteria: increased ratios of saturated to unsaturated fatty acids, increased ratios of trans- to cis-monoenoic fatty acids, and increased ratios of cyclopropyl to monoenoic precursor fatty acids. The Arthrobacter strains showed few changes in PLFAs. Environmental conditions strongly influenced PLFA profiles. 40 refs., 7 figs.

  11. Suppression of ricinoleic acid toxicity by ptl2 overexpression in fission yeast Schizosaccharomyces pombe.

    PubMed

    Yazawa, Hisashi; Ogiso, Masayo; Kumagai, Hiromichi; Uemura, Hiroshi

    2014-11-01

    We previously succeeded to obtain a high content of ricinoleic acid (RA), a hydroxylated fatty acid with great values as a petrochemical replacement, in fission yeast Schizosaccharomyces pombe by introducing Claviceps purpurea oleate Δ12-hydroxylase gene (CpFAH12). Although the production was toxic to S. pombe cells, we identified plg7, encoding phospholipase A2, as a multicopy suppressor that restored the growth defect by removing RA from phospholipids and induced secretion of a part of the released free RA into culture media. In this study, we extended our analysis and examined the effect of triglyceride (TG) lipase overexpression on the tolerance to RA toxicity and RA productivity. S. pombe has three TG lipase genes, ptl1, ptl2, and ptl3, which have high protein sequence similarities to each other and to Saccharomyces cerevisiae counterparts TGL3, TGL4, and TGL5, but only ptl2 overexpression suppressed the growth defect induced by RA production, and the culture grown at 20 °C secreted free RA into media like plg7 overexpression. Suppression by ptl2 was independent of plg7, and a large amount of free RA was accumulated in the cells concomitant with the decrease in RA moieties in phospholipids. Furthermore, the suppression by ptl2 was attenuated by bromoenol lactone (BEL), a phospholipase A2 specific inhibitor, suggesting that Ptl2p may have phospholipase activity. Simultaneous overexpression of ptl2 and plg7 in the FAH12 integrant increased secretion and intracellular accumulation of RA 1.2- and 1.3-fold, respectively, compared to those with single overexpression of plg7 on day 10 at 20 °C. PMID:25109267

  12. Phytic acid degrading lactic acid bacteria in tef-injera fermentation.

    PubMed

    Fischer, Maren M; Egli, Ines M; Aeberli, Isabelle; Hurrell, Richard F; Meile, Leo

    2014-11-01

    Ethiopian injera, a soft pancake, baked from fermented batter, is preferentially prepared from tef (Eragrostis tef) flour. The phytic acid (PA) content of tef is high and is only partly degraded during the fermentation step. PA chelates with iron and zinc in the human digestive tract and strongly inhibits their absorption. With the aim to formulate a starter culture that would substantially degrade PA during injera preparation, we assessed the potential of microorganisms isolated from Ethiopian household-tef fermentations to degrade PA. Lactic acid bacteria (LAB) were found to be among the dominating microorganisms. Seventy-six isolates from thirteen different tef fermentations were analyzed for phytase activity and thirteen different isolates of seven different species were detected to be positive in a phytase screening assay. In 20-mL model tef fermentations, out of these thirteen isolates, the use of Lactobacillus (L.) buchneri strain MF58 and Pediococcus pentosaceus strain MF35 resulted in lowest PA contents in the fermented tef of 41% and 42%, respectively of its initial content. In comparison 59% of PA remained when spontaneously fermented. Full scale tef fermentation (0.6L) and injera production using L. buchneri MF58 as culture additive decreased PA in cooked injera from 1.05 to 0.34±0.02 g/100 g, representing a degradation of 68% compared to 42% in injera from non-inoculated traditional fermentation. The visual appearance of the pancakes was similar. The final molar ratios of PA to iron of 4 and to zinc of 12 achieved with L. buchneri MF58 were decreased by ca. 50% compared to the traditional fermentation. In conclusion, selected LAB strains in tef fermentations can degrade PA, with L. buchneri MF58 displaying the highest PA degrading potential. The 68% PA degradation achieved by the application of L. buchneri MF58 would be expected to improve human zinc absorption from tef-injera, but further PA degradation is probably necessary if iron absorption has to

  13. Citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 and purification of citric acid.

    PubMed

    Wang, Ling-Fei; Wang, Zhi-Peng; Liu, Xiao-Yan; Chi, Zhen-Ming

    2013-11-01

    In this study, citric acid production from extract of Jerusalem artichoke tubers by the genetically engineered yeast Yarrowia lipolytica strain 30 was investigated. After the compositions of the extract of Jerusalem artichoke tubers for citric acid production were optimized, the results showed that natural components of extract of Jerusalem artichoke tubers without addition of any other components were suitable for citric acid production by the yeast strain. During 10 L fermentation using the extract containing 84.3 g L(-1) total sugars, 68.3 g L(-1) citric acid was produced and the yield of citric acid was 0.91 g g(-1) within 336 h. At the end of the fermentation, 9.2 g L(-1) of residual total sugar and 2.1 g L(-1) of reducing sugar were left in the fermented medium. At the same time, citric acid in the supernatant of the culture was purified. It was found that 67.2 % of the citric acid in the supernatant of the culture was recovered and purity of citric acid in the crystal was 96 %. PMID:23584740

  14. Efficiency of fatty acid synthesis by oleaginous yeasts: Prediction of yield and fatty acid cell content from consumed C/N ratio by a simple method.

    PubMed

    Granger, L M; Perlot, P; Goma, G; Pareilleux, A

    1993-11-20

    In nitrogen-limited media, growth and fatty acid formation by the oleaginous yeast Rhodotorula glutinis, i.e., yield and fatty acid cell content, have been characterized regarding carbon and nitrogen availabilities. It was shown that the formation of fatty acid free biomass was limited by nitrogen availability, whereas the fatty acid production was directly dependent on the consumed C/N ratio. According to these observations, the fraction of substrate consumed for fatty acid synthesis was estimated by using a simple method based on the actual yields, i.e., the mass of carbon source strictly converted into fatty acids and fatty acid free biomass. From these results, relationships were established allowing to predict in a simple and performing manner the maximal attainable fatty acid cell content and yield from the available carbon and nitrogen. These relationships were validated by using experimental data obtained by various authors with different yeast strains, and the proposed method was compared to the energetic and mass balance method previously described. PMID:18609663

  15. Antibacterial activity of hen egg white lysozyme modified by heat and enzymatic treatments against oenological lactic acid bacteria and acetic acid bacteria.

    PubMed

    Carrillo, W; García-Ruiz, A; Recio, I; Moreno-Arribas, M V

    2014-10-01

    The antimicrobial activity of heat-denatured and hydrolyzed hen egg white lysozyme against oenological lactic acid and acetic acid bacteria was investigated. The lysozyme was denatured by heating, and native and heat-denatured lysozymes were hydrolyzed by pepsin. The lytic activity against Micrococcus lysodeikticus of heat-denatured lysozyme decreased with the temperature of the heat treatment, whereas the hydrolyzed lysozyme had no enzymatic activity. Heat-denatured and hydrolyzed lysozyme preparations showed antimicrobial activity against acetic acid bacteria. Lysozyme heated at 90°C exerted potent activity against Acetobacter aceti CIAL-106 and Gluconobacter oxydans CIAL-107 with concentrations required to obtain 50% inhibition of growth (IC50) of 0.089 and 0.013 mg/ml, respectively. This preparation also demonstrated activity against Lactobacillus casei CIAL-52 and Oenococcus oeni CIAL-91 (IC50, 1.37 and 0.45 mg/ml, respectively). The two hydrolysates from native and heat-denatured lysozyme were active against O. oeni CIAL-96 (IC50, 2.77 and 0.3 mg/ml, respectively). The results obtained suggest that thermal and enzymatic treatments increase the antibacterial spectrum of hen egg white lysozyme in relation to oenological microorganisms. PMID:25285490

  16. Organism-Adapted Specificity of the Allosteric Regulation of Pyruvate Kinase in Lactic Acid Bacteria

    PubMed Central

    Veith, Nadine; Feldman-Salit, Anna; Cojocaru, Vlad; Henrich, Stefan; Kummer, Ursula; Wade, Rebecca C.

    2013-01-01

    Pyruvate kinase (PYK) is a critical allosterically regulated enzyme that links glycolysis, the primary energy metabolism, to cellular metabolism. Lactic acid bacteria rely almost exclusively on glycolysis for their energy production under anaerobic conditions, which reinforces the key role of PYK in their metabolism. These organisms are closely related, but have adapted to a huge variety of native environments. They include food-fermenting organisms, important symbionts in the human gut, and antibiotic-resistant pathogens. In contrast to the rather conserved inhibition of PYK by inorganic phosphate, the activation of PYK shows high variability in the type of activating compound between different lactic acid bacteria. System-wide comparative studies of the metabolism of lactic acid bacteria are required to understand the reasons for the diversity of these closely related microorganisms. These require knowledge of the identities of the enzyme modifiers. Here, we predict potential allosteric activators of PYKs from three lactic acid bacteria which are adapted to different native environments. We used protein structure-based molecular modeling and enzyme kinetic modeling to predict and validate potential activators of PYK. Specifically, we compared the electrostatic potential and the binding of phosphate moieties at the allosteric binding sites, and predicted potential allosteric activators by docking. We then made a kinetic model of Lactococcus lactis PYK to relate the activator predictions to the intracellular sugar-phosphate conditions in lactic acid bacteria. This strategy enabled us to predict fructose 1,6-bisphosphate as the sole activator of the Enterococcus faecalis PYK, and to predict that the PYKs from Streptococcus pyogenes and Lactobacillus plantarum show weaker specificity for their allosteric activators, while still having fructose 1,6-bisphosphate play the main activator role in vivo. These differences in the specificity of allosteric activation may

  17. Metabolism of the 18O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria.

    PubMed

    DeWeerd, K A; Saxena, A; Nagle, D P; Suflita, J M

    1988-05-01

    O-methyl substituents of aromatic compounds can provide C1 growth substrates for facultative and strict anaerobic bacteria isolated from diverse environments. The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. Using high-pressure liquid chromatography and gas chromatography-mass spectral analysis, we found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium limosum, and a strain of Acetobacterium woodii metabolized 3-[methoxy-18O]methoxybenzoic acid (3-anisic acid) to 3-[hydroxy-18O]hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium, Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments. The results clearly indicate a methyl rather than methoxy group removal mechanism for such reactions. PMID:3389815

  18. Metabolism of the 18O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria.

    PubMed Central

    DeWeerd, K A; Saxena, A; Nagle, D P; Suflita, J M

    1988-01-01

    O-methyl substituents of aromatic compounds can provide C1 growth substrates for facultative and strict anaerobic bacteria isolated from diverse environments. The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. Using high-pressure liquid chromatography and gas chromatography-mass spectral analysis, we found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium limosum, and a strain of Acetobacterium woodii metabolized 3-[methoxy-18O]methoxybenzoic acid (3-anisic acid) to 3-[hydroxy-18O]hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium, Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unable to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments. The results clearly indicate a methyl rather than methoxy group removal mechanism for such reactions. PMID:3389815

  19. Yeast Extract and Silver Nitrate Induce the Expression of Phenylpropanoid Biosynthetic Genes and Induce the Accumulation of Rosmarinic Acid in Agastache rugosa Cell Culture.

    PubMed

    Park, Woo Tae; Arasu, Mariadhas Valan; Al-Dhabi, Naif Abdullah; Yeo, Sun Kyung; Jeon, Jin; Park, Jong Seok; Lee, Sook Young; Park, Sang Un

    2016-01-01

    The present study aimed to investigate the role of yeast extract and silver nitrate on the enhancement of phenylpropanoid pathway genes and accumulation of rosmarinic acid in Agastache rugosa cell cultures. The treatment of cell cultures with yeast extract (500 mg/L) and silver nitrate (30 mg/L) for varying times enhanced the expression of genes in the phenylpropanoid pathway and the production of rosmarinic acid. The results indicated that the expression of RAS and HPPR was proportional to the amount of yeast extract and silver nitrate. The transcript levels of HPPR under yeast extract treatment were 1.84-, 1.97-, and 2.86-fold higher than the control treatments after 3, 6, and 12 h, respectively, whereas PAL expression under silver nitrate treatment was 52.31-fold higher than in the non-treated controls after 24 h of elicitation. The concentration of rosmarinic acid was directly proportional to the concentration of the applied elicitors. Yeast extract supplementation documented the highest amount of rosmarinic acid at 4.98 mg/g, whereas silver nitrate addition resulted in a comparatively lower amount of rosmarinic acid at 0.65 mg/g. In conclusion, addition of yeast extract to the cell cultures enhanced the accumulation of rosmarinic acid, which was evidenced by the expression levels of the phenylpropanoid biosynthetic pathway genes in A. rugosa. PMID:27043507

  20. Spatio-Temporal Variations of High and Low Nucleic Acid Content Bacteria in an Exorheic River

    PubMed Central

    Ma, Lili; Ji, Yurui; Bartlam, Mark; Wang, Yingying

    2016-01-01

    Bacteria with high nucleic acid (HNA) and low nucleic acid (LNA) content are commonly observed in aquatic environments. To date, limited knowledge is available on their temporal and spatial variations in freshwater environments. Here an investigation of HNA and LNA bacterial abundance and their flow cytometric characteristics was conducted in an exorheic river (Haihe River, Northern China) over a one year period covering September (autumn) 2011, December (winter) 2011, April (spring) 2012, and July (summer) 2012. The results showed that LNA and HNA bacteria contributed similarly to the total bacterial abundance on both the spatial and temporal scale. The variability of HNA on abundance, fluorescence intensity (FL1) and side scatter (SSC) were more sensitive to environmental factors than that of LNA bacteria. Meanwhile, the relative distance of SSC between HNA and LNA was more variable than that of FL1. Multivariate analysis further demonstrated that the influence of geographical distance (reflected by the salinity gradient along river to ocean) and temporal changes (as temperature variation due to seasonal succession) on the patterns of LNA and HNA were stronger than the effects of nutrient conditions. Furthermore, the results demonstrated that the distribution of LNA and HNA bacteria, including the abundance, FL1 and SSC, was controlled by different variables. The results suggested that LNA and HNA bacteria might play different ecological roles in the exorheic river. PMID:27082986

  1. Genome-scale metabolic modeling and in silico analysis of lipid accumulating yeast Candida tropicalis for dicarboxylic acid production.

    PubMed

    Mishra, Pranjul; Park, Gyu-Yeon; Lakshmanan, Meiyappan; Lee, Hee-Seok; Lee, Hongweon; Chang, Matthew Wook; Ching, Chi Bun; Ahn, Jungoh; Lee, Dong-Yup

    2016-09-01

    Recently, the bio-production of α,ω-dicarboxylic acids (DCAs) has gained significant attention, which potentially leads to the replacement of the conventional petroleum-based products. In this regard, the lipid accumulating yeast Candida tropicalis, has been recognized as a promising microbial host for DCA biosynthesis: it possess the unique ω-oxidation pathway where the terminal carbon of α-fatty acids is oxidized to form DCAs with varying chain lengths. However, despite such industrial importance, its cellular physiology and lipid accumulation capability remain largely uncharacterized. Thus, it is imperative to better understand the metabolic behavior of this lipogenic yeast, which could be achieved by a systems biological approach. To this end, herein, we reconstructed the genome-scale metabolic model of C. tropicalis, iCT646, accounting for 646 unique genes, 945 metabolic reactions, and 712 metabolites. Initially, the comparative network analysis of iCT646 with other yeasts revealed several distinctive metabolic reactions, mainly within the amino acid and lipid metabolism including the ω-oxidation pathway. Constraints-based flux analysis was, then, employed to predict the in silico growth rates of C. tropicalis which are highly consistent with the cellular phenotype observed in glucose and xylose minimal media chemostat cultures. Subsequently, the lipid accumulation capability of C. tropicalis was explored in comparison with Saccharomyces cerevisiae, indicating that the formation of "citrate pyruvate cycle" is essential to the lipid accumulation in oleaginous yeasts. The in silico flux analysis also highlighted the enhanced ability of pentose phosphate pathway as NADPH source rather than malic enzyme during lipogenesis. Finally, iCT646 was successfully utilized to highlight the key directions of C. tropicalis strain design for the whole cell biotransformation application to produce long-chain DCAs from alkanes. Biotechnol. Bioeng. 2016;113: 1993-2004.

  2. Concentrated sulfite-yeast fermenting mixture as a corrosion inhibitor of copper in mixtures of sulfuric and nitric acid

    SciTech Connect

    Agaev, N.M.; Smorodin, A.E.; Rzaev, E.R.; Tyr, S.G.; Shlimak, Ya.B.; Geidarova, G.D.; Eremeeva, R.A.; Nasirov, G.N.

    1987-03-01

    At the Baku factory of residential air conditioning systems both preliminary and final pickling of copper tubing is carried out in a solution of sulfuric and nitric acids. The authors of this study, in seeking an inhibitor to control this process, evaluate the protective properties of an inhibitor based on a concentrated sulfite-yeast fermenting mixture that is generated as a common waste product by the cellulose-pulp industry. It consists of calcium, sodium, and ammonium salts of lignin sulfonic acids. Tests revealed not only its inhibiting effectiveness but also its capacity to lower toxic gas levels of nitrogen oxides in the plant environment.

  3. Genomewide expression analysis in amino acid-producing bacteria using DNA microarrays.

    PubMed

    Polen, Tino; Wendisch, Volker F

    2004-01-01

    DNA microarray technology has become an important research tool for biotechnology and microbiology. It is now possible to characterize genetic diversity and gene expression in a genomewide manner. DNA microarrays have been applied extensively to study the biology of many bacteria including Escherichia coli, but only recently have they been developed for the Gram-positive Corynebacterium glutamicum. Both bacteria are widely used for biotechnological amino acid production. In this article, in addition to the design and generation of microarrays as well as their use in hybridization experiments and subsequent data analysis, we describe recent applications of DNA microarray technology regarding amino acid production in C. glutamicum and E. coli. We also discuss the impact of functional genomics studies on fundamental as well as applied aspects of amino acid production with C. glutamicum and E. coli. PMID:15304751

  4. [Partial sequence homology of FtsZ in phylogenetics analysis of lactic acid bacteria].

    PubMed

    Zhang, Bin; Dong, Xiu-zhu

    2005-10-01

    FtsZ is a structurally conserved protein, which is universal among the prokaryotes. It plays a key role in prokaryote cell division. A partial fragment of the ftsZ gene about 800bp in length was amplified and sequenced and a partial FtsZ protein phylogenetic tree for the lactic acid bacteria was constructed. By comparing the FtsZ phylogenetic tree with the 16S rDNA tree, it was shown that the two trees were similar in topology. Both trees revealed that Pediococcus spp. were closely related with L. casei group of Lactobacillus spp. , but less related with other lactic acid cocci such as Enterococcus and Streptococcus. The results also showed that the discriminative power of FtsZ was higher than that of 16S rDNA for either inter-species or inter-genus and could be a very useful tool in species identification of lactic acid bacteria. PMID:16342751

  5. Use of autochthonous lactic acid bacteria starters to ferment mango juice for promoting its probiotic roles.

    PubMed

    Liao, Xue-Yi; Guo, Li-Qiong; Ye, Zhi-Wei; Qiu, Ling-Yan; Gu, Feng-Wei; Lin, Jun-Fang

    2016-05-18

    Strains of Leuconostoc mesenteroides, Pediococcus pentosaceus, and Lactobacillus brevis were identified from mango fruits by partial 16S rDNA gene sequence. Based on the ability of producing mannitol and diacetyl, Leuconostoc mesenteroides MPL18 and MPL39 were selected within the lactic acid bacteria isolates, and used as mixed starters to ferment mango juice (MJ). Both the autochthonous strains grew well in fermented mango juice (FMJ) and remained viable at 9.81 log cfu mL(-1) during 30 days of storage at 4°C. The content of total sugar of FMJ was lower than that of MJ, while the concentration of mannitol was higher than that of MJ, and the concentration of diacetyl was 3.29 ± 0.12 mg L(-1). Among detected organic acids including citric acid, gallic acid, lactic acid, and acetic acid, only citric acid and gallic acid were found in MJ, while all detected organic acids were found in FMJ. The concentration of lactic acid of FMJ was the highest (78.62 ± 13.66 mM) among all detected organic acids. The DPPH radical scavenging capacity of FMJ was higher than that of MJ. Total phenolic compounds were better preserved in FMJ. The acidity and sweetness had a noticeable impact on the overall acceptance of the treated sample. PMID:26176886

  6. Cotransport of bacteria with hematite in porous media: Effects of ion valence and humic acid.

    PubMed

    Yang, Haiyan; Ge, Zhi; Wu, Dan; Tong, Meiping; Ni, Jinren

    2016-01-01

    This study investigated the influence of multiple colloids (hematite and humic acid) on the transport and deposition of bacteria (Escherichia coli) in packed porous media in both NaCl (5 mM) and CaCl2 (1 mM) solutions at pH 6. Due to the alteration of cell physicochemical properties, the presence of hematite and humic acid in cell suspensions significantly affected bacterial transport and deposition in quartz sand. Specifically, the presence of hematite (5 mg/L) decreased cell transport (increased cell deposition) in quartz sand in both NaCl and CaCl2 solutions, which could be attributed to the less negative overall zeta potentials of bacteria induced by the adsorption of positively charged hematite onto cell surfaces. The presence of a low concentration (0.1 mg/L) of humic acid in bacteria and hematite mixed suspensions reduced the adsorption of hematite onto cell surfaces, leading to increased cell transport in quartz sand in NaCl solutions, whereas, in CaCl2 solutions, the presence of 0.1 mg/L humic acid increased the formation of hematite-cell aggregates and thus decreased cell transport in quartz sand. When the concentration of humic acid was increased to 1 mg/L, enhanced cell transport was observed in both NaCl and CaCl2 solutions. The decreased adsorption of hematite onto cell surfaces as well as the competition of deposition sites on quartz sand with bacteria by the suspended humic acid contributed to the increased cell transport. PMID:26558710

  7. Homology analyses of the protein sequences of fatty acid synthases from chicken liver, rat mammary gland, and yeast

    SciTech Connect

    Chang, Soo-Ik ); Hammes, G.G. )

    1989-11-01

    Homology analyses of the protein sequences of chicken liver and rat mammary gland fatty acid synthases were carried out. The amino acid sequences of the chicken and rat enzymes are 67% identical. If conservative substitutions are allowed, 78% of the amino acids are matched. A region of low homologies exists between the functional domains, in particular around amino acid residues 1059-1264 of the chicken enzyme. Homologies between the active sites of chicken and rat and of chicken and yeast enzymes have been analyzed by an alignment method. A high degree of homology exists between the active sites of the chicken and rat enzymes. However, the chicken and yeast enzymes show a lower degree of homology. The DADPH-binding dinucleotide folds of the {beta}-ketoacyl reductase and the enoyl reductase sites were identified by comparison with a known consensus sequence for the DADP- and FAD-binding dinucleotide folds. The active sites of all of the enzymes are primarily in hydrophobic regions of the protein. This study suggests that the genes for the functional domains of fatty acid synthase were originally separated, and these genes were connected to each other by using different connecting nucleotide sequences in different species. An alternative explanation for the differences in rat and chicken is a common ancestry and mutations in the joining regions during evolution.

  8. Conversion of the mycotoxin patulin to the less toxic desoxypatulinic acid by the biocontrol yeast Rhodosporidium kratochvilovae strain LS11.

    PubMed

    Castoria, Raffaello; Mannina, Luisa; Durán-Patrón, Rosa; Maffei, Francesca; Sobolev, Anatoly P; De Felice, Dario V; Pinedo-Rivilla, Cristina; Ritieni, Alberto; Ferracane, Rosalia; Wright, Sandra A I

    2011-11-01

    The infection of stored apples by the fungus Penicillium expansum causes the contamination of fruits and fruit-derived products with the mycotoxin patulin, which is a major issue in food safety. Fungal attack can be prevented by beneficial microorganisms, so-called biocontrol agents. Previous time-course thin layer chromatography analyses showed that the aerobic incubation of patulin with the biocontrol yeast Rhodosporidium kratochvilovae strain LS11 leads to the disappearance of the mycotoxin spot and the parallel emergence of two new spots, one of which disappears over time. In this work, we analyzed the biodegradation of patulin effected by LS11 through HPLC. The more stable of the two compounds was purified and characterized by nuclear magnetic resonance as desoxypatulinic acid, whose formation was also quantitated in patulin degradation experiments. After R. kratochvilovae LS11 had been incubated in the presence of (13)C-labeled patulin, label was traced to desoxypatulinic acid, thus proving that this compound derives from the metabolization of patulin by the yeast. Desoxypatulinic acid was much less toxic than patulin to human lymphocytes and, in contrast to patulin, did not react in vitro with the thiol-bearing tripeptide glutathione. The lower toxicity of desoxypatulinic acid is proposed to be a consequence of the hydrolysis of the lactone ring and the loss of functional groups that react with thiol groups. The formation of desoxypatulinic acid from patulin represents a novel biodegradation pathway that is also a detoxification process. PMID:21928828

  9. Effect of camelina oil or live yeasts (Saccharomyces cerevisiae) on ruminal methane production, rumen fermentation, and milk fatty acid composition in lactating cows fed grass silage diets.

    PubMed

    Bayat, A R; Kairenius, P; Stefański, T; Leskinen, H; Comtet-Marre, S; Forano, E; Chaucheyras-Durand, F; Shingfield, K J

    2015-05-01

    The potential of dietary supplements of 2 live yeast strains (Saccharomyces cerevisiae) or camelina oil to lower ruminal methane (CH4) and carbon dioxide (CO2) production and the associated effects on animal performance, rumen fermentation, rumen microbial populations, nutrient metabolism, and milk fatty acid (FA) composition of cows fed grass silage-based diets were examined. Four Finnish Ayrshire cows (53±7 d in milk) fitted with rumen cannula were used in a 4×4 Latin square with four 42-d periods. Cows received a basal total mixed ration (control treatment) with a 50:50 forage-to-concentrate ratio [on a dry matter (DM) basis] containing grass silage, the same basal total mixed ration supplemented with 1 of 2 live yeasts, A or B, administered directly in the rumen at 10(10) cfu/d (treatments A and B), or supplements of 60g of camelina oil/kg of diet DM that replaced concentrate ingredients in the basal total mixed ration (treatment CO). Relative to the control, treatments A and B had no effects on DM intake, rumen fermentation, ruminal gas production, or apparent total-tract nutrient digestibility. In contrast, treatment CO lowered DM intake and ruminal CH4 and CO2 production, responses associated with numerical nonsignificant decreases in total-tract organic matter digestibility, but no alterations in rumen fermentation characteristics or changes in the total numbers of rumen bacteria, methanogens, protozoa, and fungi. Compared with the control, treatment CO decreased the yields of milk, milk fat, lactose, and protein. Relative to treatment B, treatment CO improved nitrogen utilization due to a lower crude protein intake. Treatment A had no influence on milk FA composition, whereas treatment B increased cis-9 10:1 and decreased 11-cyclohexyl 11:0 and 24:0 concentrations. Treatment CO decreased milk fat 8:0 to 16:0 and total saturated FA, and increased 18:0, 18:1, 18:2, conjugated linoleic acid, 18:3n-3, and trans FA concentrations. Decreases in ruminal CH4

  10. Production and transformation of dissolved neutral sugars and amino acids by bacteria in seawater

    NASA Astrophysics Data System (ADS)

    Jørgensen, L.; Lechtenfeld, O. J.; Benner, R.; Middelboe, M.; Stedmon, C. A.

    2014-10-01

    Dissolved organic matter (DOM) in the ocean consists of a heterogeneous mixture of molecules, most of which are of unknown origin. Neutral sugars and amino acids are among the few recognizable biomolecules in DOM, and the molecular composition of these biomolecules is shaped primarily by biological production and degradation processes. This study provides insight into the bioavailability of biomolecules as well as the chemical composition of DOM produced by bacteria. The molecular compositions of combined neutral sugars and amino acids were investigated in DOM produced by bacteria and in DOM remaining after 32 days of bacterial degradation. Results from bioassay incubations with natural seawater (sampled from water masses originating from the surface waters of the Arctic Ocean and the North Atlantic Ocean) and artificial seawater indicate that the molecular compositions following bacterial degradation are not strongly influenced by the initial substrate or bacterial community. The molecular composition of neutral sugars released by bacteria was characterized by a high glucose content (47 mol %) and heterogeneous contributions from other neutral sugars (3-14 mol %). DOM remaining after bacterial degradation was characterized by a high galactose content (33 mol %), followed by glucose (22 mol %) and the remaining neutral sugars (7-11 mol %). The ratio of D-amino acids to L-amino acids increased during the experiments as a response to bacterial degradation, and after 32 days, the D/L ratios of aspartic acid, glutamic acid, serine and alanine reached around 0.79, 0.32, 0.30 and 0.51 in all treatments, respectively. The striking similarity in neutral sugar and amino acid compositions between natural (representing marine semi-labile and refractory DOM) and artificial (representing bacterially produced DOM) seawater samples, suggests that microbes transform bioavailable neutral sugars and amino acids into a common, more persistent form.

  11. Isolation of acetic, propionic and butyric acid-forming bacteria from biogas plants.

    PubMed

    Cibis, Katharina Gabriela; Gneipel, Armin; König, Helmut

    2016-02-20

    In this study, acetic, propionic and butyric acid-forming bacteria were isolated from thermophilic and mesophilic biogas plants (BGP) located in Germany. The fermenters were fed with maize silage and cattle or swine manure. Furthermore, pressurized laboratory fermenters digesting maize silage were sampled. Enrichment cultures for the isolation of acid-forming bacteria were grown in minimal medium supplemented with one of the following carbon sources: Na(+)-dl-lactate, succinate, ethanol, glycerol, glucose or a mixture of amino acids. These substrates could be converted by the isolates to acetic, propionic or butyric acid. In total, 49 isolates were obtained, which belonged to the phyla Firmicutes, Tenericutes or Thermotogae. According to 16S rRNA gene sequences, most isolates were related to Clostridium sporosphaeroides, Defluviitoga tunisiensis and Dendrosporobacter quercicolus. Acetic, propionic or butyric acid were produced in cultures of isolates affiliated to Bacillus thermoamylovorans, Clostridium aminovalericum, Clostridium cochlearium/Clostridium tetani, C. sporosphaeroides, D. quercicolus, Proteiniborus ethanoligenes, Selenomonas bovis and Tepidanaerobacter sp. Isolates related to Thermoanaerobacterium thermosaccharolyticum produced acetic, butyric and lactic acid, and isolates related to D. tunisiensis formed acetic acid. Specific primer sets targeting 16S rRNA gene sequences were designed and used for real-time quantitative PCR (qPCR). The isolates were physiologically characterized and their role in BGP discussed. PMID:26779817

  12. Study of the possible mechanisms involved in the mucosal immune system activation by lactic acid bacteria.

    PubMed

    Perdigón, G; Vintiñi, E; Alvarez, S; Medina, M; Medici, M

    1999-06-01

    The induction of a mucosal immune response is not easy due to the development of oral tolerance, but under some conditions, bacteria can activate this immune system. Antigens administered orally can interact with M cells of Peyer's patches or bind to the epithelial cells. We have demonstrated that certain lactic acid bacteria are able to induce specific secretory immunity, and others will enhance the gut inflammatory immune response. The aim of this work was to establish the reason for these different behaviors and to define possible mechanisms involved in the interaction of lactic acid bacteria at the intestinal level. We studied IgA+ and IgM+ B cells comparatively in bronchus and intestine and CD4+ T cells and IgA anti-lactic acid bacteria antibodies in the intestinal fluid, induced by oral administration of Lactobacillus casei, Lb. delbrueckii ssp. bulgaricus, Lb. acidophilus, Lb. plantarum, Lb. rhamnosus, Lactococcus lactis, and Streptococcus salivarius ssp. thermophilus. The increase in the IgA+ B cells in the bronchus means that these lactic acid bacteria were able to induce the IgA cycle by interaction with M cells from Peyer's patches or intestinal epithelial cells. The IgM+ cells increased when the stimulus did not induce the switch from IgM+ to IgA+. The increase in the CD4+ cells suggests interaction of Peyer's patches and enhancement of the B- and T-cell migration. The anti-lactic acid bacteria antibody is related to the processing and presentation of the microorganisms to the immune cells. We demonstrated that Lb. casei and Lb. plantarum were able to interact with Peyer's patch cells and showed an increase in IgA-, CD4+ cells, and antibodies specific for the stimulating strain. Lactobacillus acidophilus induced gut mucosal activation by interaction with the epithelial cells without increase in the immune cells associated with the bronchus. Although Lb. rhamnosus and Strep. salivarius ssp. thermophilus interact with epithelial cells, they also induced

  13. [Studies on the effects of carbon:nitrogen ratio, inoculum type and yeast extract addition on jasmonic acid production by Botryodiplodia theobromae Pat. strain RC1].

    PubMed

    Eng Sánchez, Felipe; Gutiérrez-Rojas, Mariano; Favela-Torres, Ernesto

    2008-09-30

    Jasmonic acid is a native plant growth regulator produced by algae, microorganisms and higher plants. This regulator is involved in the activation of defence mechanisms against pathogens and wounding in plants. Studies concerning the effects of carbon: nitrogen ratio (C/Nr: 17, 35 and 70), type of inoculum (spores or mycelium) and the yeast extract addition in the media on jasmonic acid production by Botryodiplodia theobromae were evaluated. Jasmonic acid production was stimulated at the carbon: nitrogen ratio of 17. Jasmonic acid productivity was higher in the media inoculated with mycelium and in the media with yeast extract 1.7 and 1.3 times, respectively. PMID:18785793

  14. Polyunsaturated fatty acid saturation by gut lactic acid bacteria affecting host lipid composition

    PubMed Central

    Kishino, Shigenobu; Takeuchi, Michiki; Park, Si-Bum; Hirata, Akiko; Kitamura, Nahoko; Kunisawa, Jun; Kiyono, Hiroshi; Iwamoto, Ryo; Isobe, Yosuke; Arita, Makoto; Arai, Hiroyuki; Ueda, Kazumitsu; Shima, Jun; Takahashi, Satomi; Yokozeki, Kenzo; Shimizu, Sakayu; Ogawa, Jun

    2013-01-01

    In the representative gut bacterium Lactobacillus plantarum, we identified genes encoding the enzymes involved in a saturation metabolism of polyunsaturated fatty acids and revealed in detail the metabolic pathway that generates hydroxy fatty acids, oxo fatty acids, conjugated fatty acids, and partially saturated trans-fatty acids as intermediates. Furthermore, we observed these intermediates, especially hydroxy fatty acids, in host organs. Levels of hydroxy fatty acids were much higher in specific pathogen-free mice than in germ-free mice, indicating that these fatty acids are generated through polyunsaturated fatty acids metabolism of gastrointestinal microorganisms. These findings suggested that lipid metabolism by gastrointestinal microbes affects the health of the host by modifying fatty acid composition. PMID:24127592

  15. Occurrence of Arginine Deiminase Pathway Enzymes in Arginine Catabolism by Wine Lactic Acid Bacteria

    PubMed Central

    Liu, S.; Pritchard, G. G.; Hardman, M. J.; Pilone, G. J.

    1995-01-01

    l-Arginine, an amino acid found in significant quantities in grape juice and wine, is known to be catabolized by some wine lactic acid bacteria. The correlation between the occurrence of arginine deiminase pathway enzymes and the ability to catabolize arginine was examined in this study. The activities of the three arginine deiminase pathway enzymes, arginine deiminase, ornithine transcarbamylase, and carbamate kinase, were measured in cell extracts of 35 strains of wine lactic acid bacteria. These enzymes were present in all heterofermentative lactobacilli and most leuconostocs but were absent in all the homofermentative lactobacilli and pediococci examined. There was a good correlation among arginine degradation, formation of ammonia and citrulline, and the occurrence of arginine deiminase pathway enzymes. Urea was not detected during arginine degradation, suggesting that the catabolism of arginine did not proceed via the arginase-catalyzed reaction, as has been suggested in some earlier studies. Detection of ammonia with Nessler's reagent was shown to be a simple, rapid test to assess the ability of wine lactic acid bacteria to degrade arginine, although in media containing relatively high concentrations (>0.5%) of fructose, ammonia formation is inhibited. PMID:16534912

  16. Effects of Lactic Acid-Forming Bacteria on Vibrio comma Inoculated into Intestinal Segments of Rabbits

    PubMed Central

    Hattori, Zenpachiro; Misawa, Hiroshi; Igarashi, Isamu; Sugiya, Yukio

    1965-01-01

    Hattori, H. (Sankyo Co., Ltd., Tokyo, Japan), H. Misawa, I. Igarashi, and Y. Sugiya. Effects of lactic acid-forming bacteria on Vibrio comma inoculated into intestinal segments of rabbits. J. Bacteriol. 90:541–545. 1965.—Mixed inocula of Vibrio comma KC-4 and various lactic acid-forming bacteria were injected into the intestinal segments of rabbits (De and Chatterje, 1953) to observe the effects of the latter agents in altering the changes produced by strain KC-4. The animals were sacrificed 10 and 20 hr after inoculation. The inoculated intestinal segments were first examined grossly, and the amount of exudate in the segments, if any, was measured, after which the tissues were subjected to pathological examination. When KC-4 cells together with spore-bearing lactic acid-forming bacilli, strain P-22, or Lactobacillus casei were introduced, the intestinal segments showed few or no macroscopic and microscopic changes, and no accumulation of exudate. With mixed inoculation with lactic acid bacteria such as L. bulgaricus, L. acidophilus, Streptococcus lactis, and S. faecalis, changes were produced by strain KC-4. Macroscopically, no difference was discernible between the changes caused by mixed inoculation and those produced by single inoculation of KC-4. Upon pathological examination, however, it was seen that changes resulting from mixed inoculation were slightly less severe than those produced by inoculation with strain KC-4 only. Images PMID:14329471

  17. Lactic acid bacteria convert glucosinolates to nitriles efficiently yet differently from enterobacteriaceae.

    PubMed

    Mullaney, Jane A; Kelly, William J; McGhie, Tony K; Ansell, Juliet; Heyes, Julian A

    2013-03-27

    Glucosinolates from the genus Brassica can be converted into bioactive compounds known to induce phase II enzymes, which may decrease the risk of cancers. Conversion via hydrolysis is usually by the brassica enzyme myrosinase, which can be inactivated by cooking or storage. We examined the potential of three beneficial bacteria, Lactobacillus plantarum KW30, Lactococcus lactis subsp. lactis KF147, and Escherichia coli Nissle 1917, and known myrosinase-producer Enterobacter cloacae to catalyze the conversion of glucosinolates in broccoli extract. Enterobacteriaceae consumed on average 65% glucoiberin and 78% glucoraphanin, transforming them into glucoiberverin and glucoerucin, respectively, and small amounts of iberverin nitrile and erucin nitrile. The lactic acid bacteria did not accumulate reduced glucosinolates, consuming all at 30-33% and transforming these into iberverin nitrile, erucin nitrile, sulforaphane nitrile, and further unidentified metabolites. Adding beneficial bacteria to a glucosinolate-rich diet may increase glucosinolate transformation, thereby increasing host exposure to bioactives. PMID:23461529

  18. Aflatoxin B1 binding capacity of autochthonous strains of lactic acid bacteria.

    PubMed

    Fazeli, Mohammad R; Hajimohammadali, M; Moshkani, Azamossadat; Samadi, Nasrin; Jamalifar, Hossein; Khoshayand, Mohammad R; Vaghari, Elham; Pouragahi, Samieh

    2009-01-01

    Some foods are prone to contamination with aflatoxins, with detrimental effect on human health. Lactic acid bacteria have been reported to bind aflatoxins and remove them from foods and feeds. Reduction of aflatoxin B1 (AFB1) from the liquid media by the autochthonous lactic acid bacteria (Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus fermentum) isolated from traditional Iranian sourdough and dairy products is reported in the current study. The effect of incubation time on the binding capacity of the strains to AFB1 was also investigated. Duplicates of individual bacteria with population equivalent to 2 X 10(10) CFU/ml were incubated in the presence of AFB1 at 37 degrees C for a period of 72 h, and the amounts of unbound AFB1 were quantitated by reverse-phase high-performance liquid chromatography. All the strains were capable of removal of AFB1, and the reduction of AFB1 ranged from 25 to 61% throughout the incubation period. Removal of AFB1 was a rapid process, with approximately 61 and 56% of the toxin taken instantly by L. fermentum and L. plantarum, respectively. Binding was of a reversible nature, and some of the bound AFB1 was released into the media by the repeated centrifugation and resuspension of the cell pellets. The stability of the bacteria-toxin complex was strain dependent, and L. casei was a stronger binder of AFB1 compared with the other bacteria. No toxin release was observed after 24 h. These findings tend to suggest that certain novel probiotic bacteria with high aflatoxin binding capacity could be selected for detoxification of foods. PMID:19205485

  19. Impact of gluconic fermentation of strawberry using acetic acid bacteria on amino acids and biogenic amines profile.

    PubMed

    Ordóñez, J L; Sainz, F; Callejón, R M; Troncoso, A M; Torija, M J; García-Parrilla, M C

    2015-07-01

    This paper studies the amino acid profile of beverages obtained through the fermentation of strawberry purée by a surface culture using three strains belonging to different acetic acid bacteria species (one of Gluconobacter japonicus, one of Gluconobacter oxydans and one of Acetobacter malorum). An HPLC-UV method involving diethyl ethoxymethylenemalonate (DEEMM) was adapted and validated. From the entire set of 21 amino acids, multiple linear regressions showed that glutamine, alanine, arginine, tryptophan, GABA and proline were significantly related to the fermentation process. Furthermore, linear discriminant analysis classified 100% of the samples correctly in accordance with the microorganism involved. G. japonicus consumed glucose most quickly and achieved the greatest decrease in amino acid concentration. None of the 8 biogenic amines were detected in the final products, which could serve as a safety guarantee for these strawberry gluconic fermentation beverages, in this regard. PMID:25704705

  20. Fast and accurate preparation fatty acid methyl esters by microwave-assisted derivatization in the yeast Saccharomyces cerevisiae.

    PubMed

    Khoomrung, Sakda; Chumnanpuen, Pramote; Jansa-ard, Suwanee; Nookaew, Intawat; Nielsen, Jens

    2012-06-01

    We present a fast and accurate method for preparation of fatty acid methyl esters (FAMEs) using microwave-assisted derivatization of fatty acids present in yeast samples. The esterification of free/bound fatty acids to FAMEs was completed within 5 min, which is 24 times faster than with conventional heating methods. The developed method was validated in two ways: (1) through comparison with a conventional method (hot plate) and (2) through validation with the standard reference material (SRM) 3275-2 omega-3 and omega-6 fatty acids in fish oil (from the Nation Institute of Standards and Technology, USA). There were no significant differences (P>0.05) in yields of FAMEs with both validations. By performing a simple modification of closed-vessel microwave heating, it was possible to carry out the esterification in Pyrex glass tubes kept inside the closed vessel. Hereby, we are able to increase the number of sample preparations to several hundred samples per day as the time for preparation of reused vessels was eliminated. Pretreated cell disruption steps are not required, since the direct FAME preparation provides equally quantitative results. The new microwave-assisted derivatization method facilitates the preparation of FAMEs directly from yeast cells, but the method is likely to also be applicable for other biological samples. PMID:22569641

  1. Involvement of multiple basic amino acids in yeast ribosomal protein L1 in 5S rRNA recognition.

    PubMed

    Yeh, L C; Lee, J C

    1995-01-01

    The role of basic amino acid residues located at the C-terminal region of the yeast ribosomal protein L1 in 5S rRNA binding was characterized in vitro and in vivo. Mutant proteins containing single or multiple amino acid substitutions were generated by site-directed mutagenesis of the L1 gene carried on a plasmid. In vitro RNP formation was examined by production of the mutant protein in the presence of the RNA molecule. The thermostability of the resultant RNP was also studied. Effects of these mutations on cell viability and ribosome assembly were characterized by transformation of a conditional null L1 yeast mutant with the mutated L1 gene expressed from the plasmid. Substitution of any one of the lysine or arginine residue did not affect significantly RNA binding in vitro or cell growth in vivo. However, several mutant proteins with substitutions of two of these basic amino acids bound RNA weakly and the RNPs were less stable. Cells expressing these mutant proteins were lethal. Theoretical structural prediction of these amino acids further provided information regarding their collective contributions to RNA recognition and to interaction between the RNP and other components of the 60S ribosomal subunit. PMID:8643400

  2. Novel Simplified and Rapid Method for Screening and Isolation of Polyunsaturated Fatty Acids Producing Marine Bacteria

    PubMed Central

    Tilay, Ashwini; Annapure, Uday

    2012-01-01

    Bacterial production of polyunsaturated fatty acids (PUFAs) is a potential biotechnological approach for production of valuable nutraceuticals. Reliable method for screening of number of strains within short period of time is great need. Here, we report a novel simplified method for screening and isolation of PUFA-producing bacteria by direct visualization using the H2O2-plate assay. The oxidative stability of PUFAs in growing bacteria towards added H2O2 is a distinguishing characteristic between the PUFAs producers (no zone of inhibition) and non-PUFAs producers (zone of inhibition) by direct visualization. The confirmation of assay results was performed by injecting fatty acid methyl esters (FAMEs) produced by selected marine bacteria to Gas Chromatography-Mass Spectrometry (GCMS). To date, this assay is the most effective, inexpensive, and specific method for bacteria producing PUFAs and shows drastically reduction in the number of samples thus saves the time, effort, and cost of screening and isolating strains of bacterial PUFAs producers. PMID:22934188

  3. Phenotypic and Genotypic Characterization of Some Lactic Acid Bacteria Isolated from Bee Pollen: A Preliminary Study

    PubMed Central

    BELHADJ, Hani; HARZALLAH, Daoud; BOUAMRA, Dalila; KHENNOUF, Seddik; Dahamna, Saliha; GHADBANE, Mouloud

    2014-01-01

    In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133. PMID:24936378

  4. Phenotypic and genotypic characterization of some lactic Acid bacteria isolated from bee pollen: a preliminary study.

    PubMed

    Belhadj, Hani; Harzallah, Daoud; Bouamra, Dalila; Khennouf, Seddik; Dahamna, Saliha; Ghadbane, Mouloud

    2014-01-01

    In the present work, five hundred and sixty-seven isolates of lactic acid bacteria were recovered from raw bee pollen grains. All isolates were screened for their antagonistic activity against both Gram-positive and Gram-negative pathogenic bacteria. Neutralized supernatants of 54 lactic acid bacteria (LAB) cultures from 216 active isolates inhibited the growth of indicator bacteria. They were phenotypically characterized, based on the fermentation of 39 carbohydrates. Using the simple matching coefficient and unweighted pair group algorithm with arithmetic averages (UPGMA), seven clusters with other two members were defined at the 79% similarity level. The following species were characterized: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Pediococcus acidilactici, Pediococcus pentosaceus, and unidentified lactobacilli. Phenotypic characteristics of major and minor clusters were also identified. Partial sequencing of the 16S rRNA gene of representative isolates from each cluster was performed, and ten strains were assigned to seven species: Lactobacillus plantarum, Lactobacillus fermentum, Lactococcus lactis, Lactobacillus ingluviei, Pediococcus pentosaceus, Lactobacillus acidipiscis and Weissella cibaria. The molecular method used failed to determine the exact taxonomic status of BH0900 and AH3133. PMID:24936378

  5. The aflatoxin B1 isolating potential of two lactic acid bacteria

    PubMed Central

    Hamidi, Adel; Mirnejad, Reza; Yahaghi, Emad; Behnod, Vahid; Mirhosseini, Ali; Amani, Sajad; Sattari, Sara; Darian, Ebrahim Khodaverdi

    2013-01-01

    Objective To determine lactic acid bacteria's capability to enhance the process of binding and isolating aflatoxin B1 and to utilize such lactic acid bacteria as a food supplement or probiotic products for preventing absorption of aflatoxin B1 in human and animal bodies. Methods In the present research, the bacteria were isolated from five different sources. For surveying the capability of the bacteria in isolating aflatoxin B1, ELISA method was implemented, and for identifying the resultant strains through 16S rRNA sequencing method, universal primers were applied. Results Among the strains which were isolated, two strains of Lactobacillus pentosus and Lactobacillus beveris exhibited the capability of absorbing and isolating aflatoxin B1 by respectively absorbing and discharging 17.4% and 34.7% of the aforementioned toxin existing in the experiment solution. Conclusions Strains of Lactobacillus pentosus and Lactobacillus beveris were isolated from human feces and local milk samples, respectively. And both strains has the ability to isolate or bind with aflatoxin B1. PMID:23998015

  6. Application of Lactic Acid Bacteria (LAB) in freshness keeping of tilapia fillets as sashimi

    NASA Astrophysics Data System (ADS)

    Cao, Rong; Liu, Qi; Chen, Shengjun; Yang, Xianqing; Li, Laihao

    2015-08-01

    Aquatic products are extremely perishable food commodities. Developing methods to keep the freshness of fish represents a major task of the fishery processing industry. Application of Lactic Acid Bacteria (LAB) as food preservative is a novel approach. In the present study, the possibility of using lactic acid bacteria in freshness keeping of tilapia fillets as sashimi was examined. Fish fillets were dipped in Lactobacillus plantarum 1.19 (obtained from China General Microbiological Culture Collection Center) suspension as LAB-treated group. Changes in K-value, APC, sensory properties and microbial flora were analyzed. Results showed that LAB treatment slowed the increase of K-value and APC in the earlier storage, and caused a smooth decrease in sensory score. Gram-negative bacteria dominated during refrigerated storage, with Pseudomonas and Aeromonas being relatively abundant. Lactobacillus plantarum 1.19 had no obvious inhibitory effect against these Gram-negatives. However, Lactobacillus plantarum 1.19 changed the composition of Gram-positive bacteria. No Micrococcus were detected and the proportion of Staphylococcus decreased in the spoiled LAB-treated samples. The period that tilapia fillets could be used as sashimi material extended from 24 h to 48 h after LAB treatment. The potential of using LAB in sashimi processing was confirmed.

  7. Dual-coated lactic acid bacteria: an emerging innovative technology in the field of probiotics.

    PubMed

    Alvarez-Calatayud, Guillermo; Margolles, Abelardo

    2016-01-01

    Probiotics are living micro-organisms that do not naturally have shelf life, and normally are weakly protected against the digestive action of the GI tract. A new dual coating technology has been developed in an effort to maximize survival, that is, to be able to reach the intestine alive and in sufficient numbers to confer the beneficial health effects on the host. Dual-coating of lactic acid bacteria (LAB) is the result of fourth-generation coating technology for the protection of these bacteria at least 100-fold or greater than the uncoated LAB. This innovative technique involves a first pH-dependent protein layer that protects bacteria from gastric acid and bile salt, and a second polysaccharide matrix that protects bacteria from external factors, such as humidity, temperature and pressure, as well as the digestive action during the passage through the GI tract. Dual-coated probiotic formulation is applicable to different therapeutic areas, including irritable bowel syndrome, atopic dermatitis, acute diarrhea, chronic constipation, Helicobacter pylori eradication, and prevention of antibiotic-associated diarrhea. An updated review of the efficacy of doubly coated probiotic strains for improving bacterial survival in the intestinal tract and its consequent clinical benefits in humans is here presented. PMID:26780116

  8. Modelling of the acid base properties of two thermophilic bacteria at different growth times

    NASA Astrophysics Data System (ADS)

    Heinrich, Hannah T. M.; Bremer, Phil J.; McQuillan, A. James; Daughney, Christopher J.

    2008-09-01

    Acid-base titrations and electrophoretic mobility measurements were conducted on the thermophilic bacteria Anoxybacillus flavithermus and Geobacillus stearothermophilus at two different growth times corresponding to exponential and stationary/death phase. The data showed significant differences between the two investigated growth times for both bacterial species. In stationary/death phase samples, cells were disrupted and their buffering capacity was lower than that of exponential phase cells. For G. stearothermophilus the electrophoretic mobility profiles changed dramatically. Chemical equilibrium models were developed to simultaneously describe the data from the titrations and the electrophoretic mobility measurements. A simple approach was developed to determine confidence intervals for the overall variance between the model and the experimental data, in order to identify statistically significant changes in model fit and thereby select the simplest model that was able to adequately describe each data set. Exponential phase cells of the investigated thermophiles had a higher total site concentration than the average found for mesophilic bacteria (based on a previously published generalised model for the acid-base behaviour of mesophiles), whereas the opposite was true for cells in stationary/death phase. The results of this study indicate that growth phase is an important parameter that can affect ion binding by bacteria, that growth phase should be considered when developing or employing chemical models for bacteria-bearing systems.

  9. Characterization of Lactic Acid Bacteria Isolated from Sauce-type Kimchi.

    PubMed

    Jung, Suk Hee; Park, Joung Whan; Cho, Il Jae; Lee, Nam Keun; Yeo, In-Cheol; Kim, Byung Yong; Kim, Hye Kyung; Hahm, Young Tae

    2012-09-01

    This study was carried out to investigate the isolation and characterization of lactic acid bacteria (LAB) from naturally fermented sauce-type kimchi. Sauce-type kimchi was prepared with fresh, chopped ingredients (Korean cabbage, radish, garlic, ginger, green onion, and red pepper). The two isolated bacteria from sauce-type kimchi were identified as Pediococcus pentosaceus and Lactobacillus brevis by 16S rDNA sequencing and tentatively named Pediococcus sp. IJ-K1 and Lactobacillus sp. IJ-K2, respectively. Pediococcus sp. IJ-K1 was isolated from the early and middle fermentation stages of sauce-type kimchi whereas Lactobacillus sp. IJ-K2 was isolated from the late fermentation stage. The resistance of Pediococcus sp. IJ-K1 and Lactobacillus sp. IJ-K2 to artificial gastric and bile acids led to bacterial survival rates that were 100% and 84.21%, respectively. PMID:24471087

  10. Immune modulation of blood leukocytes in humans by lactic acid bacteria: criteria for strain selection.

    PubMed

    Schiffrin, E J; Brassart, D; Servin, A L; Rochat, F; Donnet-Hughes, A

    1997-08-01

    Lactic acid bacteria in food can transiently colonize the intestine and exert beneficial effects (probiotic). Survival during intestinal transit or adhesion to epithelium or both seem to be important for modifying the host's immune reactivity. Because Lactobacillus acidophilus strain La1 is adherent to enterocytes in vitro, we hypothesize that contact with immune cells may occur in vivo. However, Bifidobacterium bifidum strain Bb12, which shows high fecal colonization, is another potential immunomodulator. Twenty-eight volunteers were divided into two groups and given a fermented product containing one of the two strains. Lymphocyte subsets and leukocyte phagocytic activity were studied in blood. No modifications were detected in lymphocyte subsets. In contrast, phagocytosis of Escherichia coli ssp. was enhanced in both groups (P < 0.001 for both). Bacterial adhesion to enterocytes, fecal colonization, or both seem to be valuable selection criteria for immunomodulation. Antiinfective mechanisms of defense can be enhanced after ingestion of specific lactic acid bacteria strains. PMID:9250141

  11. Effect of oxidoreduction potential on aroma biosynthesis by lactic acid bacteria in nonfat yogurt.

    PubMed

    Martin, F; Cachon, R; Pernin, K; De Coninck, J; Gervais, P; Guichard, E; Cayot, N

    2011-02-01

    The aim of this study was to investigate the effect of oxidoreduction potential (Eh) on the biosynthesis of aroma compounds by lactic acid bacteria in non-fat yogurt. The study was done with yogurts fermented by Lactobacillus bulgaricus and Streptococcus thermophilus. The Eh was modified by the application of different gaseous conditions (air, nitrogen, and nitrogen/hydrogen). Acetaldehyde, dimethyl sulfide, diacetyl, and pentane-2,3-dione, as the major endogenous odorant compounds of yogurt, were chosen as tracers for the biosynthesis of aroma compounds by lactic acid bacteria. Oxidative conditions favored the production of acetaldehyde, dimethyl sulfide, and diketones (diacetyl and pentane-2,3-dione). The Eh of the medium influences aroma production in yogurt by modifying the metabolic pathways of Lb. bulgaricus and Strep. thermophilus. The use of Eh as a control parameter during yogurt production could permit the control of aroma formation. PMID:21257030

  12. Fatty acid and hydroxy acid adaptation in three gram-negative hydrocarbon-degrading bacteria in relation to carbon source.

    PubMed

    Soltani, Mohamed; Metzger, Pierre; Largeau, Claude

    2005-12-01

    The lipids of three gram-negative bacteria, Acinetobacter calcoaceticus, Marinobacter aquaeolei, and Pseudomonas oleovorans grown on mineral media supplemented with ammonium acetate or hydrocarbons, were isolated, purified, and their structures determined. Three pools of lipids were isolated according to a sequential procedure: unbound lipids extracted with organic solvents, comprising metabolic lipids and the main part of membrane lipids, OH--labile lipids (mainly ester-bound in the lipopolysaccharides, LPS) and H+-labile lipids (mainly amide-bound in the LPS). Unsaturated FA composition gave evidence for an aerobic desaturation pathway for the synthesis of these acids in A. calcoaceticus and M. aquaeolei, a nonclassic route in gram-negative bacteria. Surprisingly, both aerobic and anaerobic pathways are operating in the studied strain of P. oleovorans. The increase of the proportion of saturated FA observed for the strain of P. oleovorans grown on light hydrocarbons would increase the temperature transition of the lipids for maintaining the inner membrane fluidity. An opposite phenomenon occurs in A. calcoaceticus and M. aquaeolei grown on solid or highly viscous C19 hydrocarbons. The increases of FA < C18 when the bacteria were grown on n-nonadecane, or of iso-FA in cultures on isononadecane would decrease the transition temperature of the lipids, to maintain the fluidity of the inner membranes. Moreover, P. oleovorans grown on hydrocarbons greatly decreases the proportion of P-hydroxy acids of LPS, thus likely maintaining the physical properties of the outer membrane. By contrast, no dramatic change in hydroxy acid composition occurred in the other two bacteria. PMID:16477811

  13. Induction of multiple pleiotropic drug resistance genes in yeast engineered to produce an increased level of anti-malarial drug precursor, artemisinic acid

    PubMed Central

    Ro, Dae-Kyun; Ouellet, Mario; Paradise, Eric M; Burd, Helcio; Eng, Diana; Paddon, Chris J; Newman, Jack D; Keasling, Jay D

    2008-01-01

    Background Due to the global occurrence of multi-drug-resistant malarial parasites (Plasmodium falciparum), the anti-malarial drug most effective against malaria is artemisinin, a natural product (sesquiterpene lactone endoperoxide) extracted from sweet wormwood (Artemisia annua). However, artemisinin is in short supply and unaffordable to most malaria patients. Artemisinin can be semi-synthesized from its precursor artemisinic acid, which can be synthesized from simple sugars using microorganisms genetically engineered with genes from A. annua. In order to develop an industrially competent yeast strain, detailed analyses of microbial physiology and development of gene expression strategies are required. Results Three plant genes coding for amorphadiene synthase, amorphadiene oxidase (AMO or CYP71AV1), and cytochrome P450 reductase, which in concert divert carbon flux from farnesyl diphosphate to artemisinic acid, were expressed from a single plasmid. The artemisinic acid production in the engineered yeast reached 250 μg mL-1 in shake-flask cultures and 1 g L-1 in bio-reactors with the use of Leu2d selection marker and appropriate medium formulation. When plasmid stability was measured, the yeast strain synthesizing amorphadiene alone maintained the plasmid in 84% of the cells, whereas the yeast strain synthesizing artemisinic acid showed poor plasmid stability. Inactivation of AMO by a point-mutation restored the high plasmid stability, indicating that the low plasmid stability is not caused by production of the AMO protein but by artemisinic acid synthesis or accumulation. Semi-quantitative reverse-transcriptase (RT)-PCR and quantitative real time-PCR consistently showed that pleiotropic drug resistance (PDR) genes, belonging to the family of ATP-Binding Cassette (ABC) transporter, were massively induced in the yeast strain producing artemisinic acid, relative to the yeast strain producing the hydrocarbon amorphadiene alone. Global transcriptional analysis by

  14. Systematic identification of genes involved in metabolic acid stress resistance in yeast and their potential as cancer targets.

    PubMed

    Shin, John J; Aftab, Qurratulain; Austin, Pamela; McQueen, Jennifer A; Poon, Tak; Li, Shu Chen; Young, Barry P; Roskelley, Calvin D; Loewen, Christopher J R

    2016-09-01

    A hallmark of all primary and metastatic tumours is their high rate of glucose uptake and glycolysis. A consequence of the glycolytic phenotype is the accumulation of metabolic acid; hence, tumour cells experience considerable intracellular acid stress. To compensate, tumour cells upregulate acid pumps, which expel the metabolic acid into the surrounding tumour environment, resulting in alkalization of intracellular pH and acidification of the tumour microenvironment. Nevertheless, we have only a limited understanding of the consequences of altered intracellular pH on cell physiology, or of the genes and pathways that respond to metabolic acid stress. We have used yeast as a genetic model for metabolic acid stress with the rationale that the metabolic changes that occur in cancer that lead to intracellular acid stress are likely fundamental. Using a quantitative systems biology approach we identified 129 genes required for optimal growth under conditions of metabolic acid stress. We identified six highly conserved protein complexes with functions related to oxidative phosphorylation (mitochondrial respiratory chain complex III and IV), mitochondrial tRNA biosynthesis [glutamyl-tRNA(Gln) amidotransferase complex], histone methylation (Set1C-COMPASS), lysosome biogenesis (AP-3 adapter complex), and mRNA processing and P-body formation (PAN complex). We tested roles for two of these, AP-3 adapter complex and PAN deadenylase complex, in resistance to acid stress using a myeloid leukaemia-derived human cell line that we determined to be acid stress resistant. Loss of either complex inhibited growth of Hap1 cells at neutral pH and caused sensitivity to acid stress, indicating that AP-3 and PAN complexes are promising new targets in the treatment of cancer. Additionally, our data suggests that tumours may be genetically sensitized to acid stress and hence susceptible to acid stress-directed therapies, as many tumours accumulate mutations in mitochondrial respiratory chain

  15. Immune Modulation Capability of Exopolysaccharides Synthesised by Lactic Acid Bacteria and Bifidobacteria.

    PubMed

    Hidalgo-Cantabrana, Claudio; López, Patricia; Gueimonde, Miguel; de Los Reyes-Gavilán, Clara G; Suárez, Ana; Margolles, Abelardo; Ruas-Madiedo, Patricia

    2012-12-01

    During recent years, the exopolysaccharides (EPS) produced by some strains of lactic acid bacteria and bifidobacteria have attracted the attention of researchers, mainly due to their potential technological applications. However, more recently, it has been observed that some of these EPS present immunomodulatory properties, which suggest a potential effect on human health. Whereas EPS from lactic acid bacteria have been studied in some detail, those of bifidobacteria largely remain uncharacterized in spite of the ubiquity of EPS genes in Bifidobacterium genomes. In this review, we have analysed the data collected in the literature about the potential immune-modulating capability of EPS produced by lactic acid bacteria and bifidobacteria. From this data analysis, as well as from results obtained in our group, a hypothesis relating the physicochemical characteristics of EPS with their immune modulation capability was highlighted. We propose that EPS having negative charge and/or small size (molecular weight) are able to act as mild stimulators of immune cells, whereas those polymers non-charged and with a large size present a suppressive profile. PMID:26782182

  16. Taxonomic homogeneity of a salt-tolerant lactic acid bacteria isolated from shoyu mash.

    PubMed

    Hanagata, Hiroshi; Shida, Osamu; Takagi, Hiroaki

    2003-04-01

    Forty-seven salt-tolerant lactic acid bacteria, which had been isolated from different places and grown in 15% NaCl, were examined to assess their taxonomic heterogeneity. Among the isolates, 42 were isolated from shoyu mash during the acid fermentation phase, 2 were from miso and 3 were from anchovy pickles. All isolates were identified as Tetragenococcus halophilus on the basis of DNA relatedness values. We further examined 102 phenotypic characteristics of them. The isolates exhibited differences in only 16, supporting the conclusion obtained from the DNA relatedness analysis. PMID:12833212

  17. Evolution of Acetic Acid Bacteria During Fermentation and Storage of Wine

    PubMed Central

    Joyeux, A.; Lafon-Lafourcade, S.; Ribéreau-Gayon, P.

    1984-01-01

    Acetic acid bacteria were present at all stages of wine making, from the mature grape through vinification to conservation. A succession of Gluconobacter oxydans, Acetobacter pasteurianus, and Acetobacter aceti during the course of these stages was noted. Low levels of A. aceti remained in the wine; they exhibited rapid proliferation on short exposure of the wine to air and caused significant increases in the concentration of acetic acid. Higher temperature of wine storage and higher wine pH favored the development and metabolism of these species. PMID:16346581

  18. Isolation of Soil Bacteria Adapted To Degrade Humic Acid-Sorbed Phenanthrene

    PubMed Central

    Vacca, D. J.; Bleam, W. F.; Hickey, W. J.

    2005-01-01

    The goal of these studies was to determine how sorption by humic acids affected the bioavailability of polynuclear aromatic hydrocarbons (PAHs) to PAH-degrading microbes. Micellar solutions of humic acid were used as sorbents, and phenanthrene was used as a model PAH. Enrichments from PAH-contaminated soils established with nonsorbed phenanthrene yielded a total of 25 different isolates representing a diversity of bacterial phylotypes. In contrast, only three strains of Burkholderia spp. and one strain each of Delftia sp. and Sphingomonas sp. were isolated from enrichments with humic acid-sorbed phenanthrene (HASP). Using [14C]phenanthrene as a radiotracer, we verified that only HASP isolates were capable of mineralizing HASP, a phenotype hence termed “competence.” Competence was an all-or-nothing phenotype: noncompetent strains showed no detectable phenanthrene mineralization in HASP cultures, but levels of phenanthrene mineralization effected by competent strains in HASP and NSP cultures were not significantly different. Levels and rates of phenanthrene mineralization exceeded those predicted to be supported solely by the metabolism of phenanthrene in the aqueous phase of HASP cultures. Thus, competent strains were able to directly access phenanthrene sorbed by the humic acids and did not rely on desorption for substrate uptake. To the best of our knowledge, this is the first report of (i) a selective interaction between aerobic bacteria and humic acid molecules and (ii) differential bioavailability to bacteria of PAHs sorbed to a natural biogeopolymer. PMID:16000791

  19. Effects of worts treated with proteases on the assimilation of free amino acids and fermentation performance of lager yeast.

    PubMed

    Lei, Hongjie; Zheng, Liye; Wang, Chenxia; Zhao, Haifeng; Zhao, Mouming

    2013-02-01

    The objective of this study was to investigate the changes in free amino acids (FAA) composition by supplementing three commercial proteases (Neutrase, Flavorzyme and Protamex) at the beginning of wort mashing, and monitoring the effects on the assimilation pattern of FAA and fermentation performance of lager yeast (Saccharomyces pastorianus) during normal and high gravity fermentations. Proteases supplementation significantly improved the extract yield and FAA level of mashed worts. Normal gravity worts treated with Flavorzyme and Neutrase exhibited higher fermentability, ethanol production and flavor volatiles concentration compared to the control worts, while these beneficial effects were observed in high gravity worts treated with Protamex and Neutrase. The reason for the above results is proposed to be the change in the assimilation pattern of FAA in lager yeast with increased wort gravity, especially for the improved assimilation ratios of Leu, Arg, Phe, His, Asp and Val. In normal gravity fermentations, there were strong correlations between the assimilation amounts of Lys, Leu, Arg and His and fermentability, while in high gravity fermentations, these good correlations were found with only Lys and His. The present study suggested that optimizing the composition of FAA by supplementing proteases during wort mashing was beneficial to beer brewing for improving fermentation performance of lager yeast and flavor volatiles formation. PMID:23279816

  20. Antagonistic activity of lactic acid bacteria as probiotics against selected bacteria of the Enterobaceriacae family in the presence of polyols and their galactosyl derivatives.

    PubMed

    Klewicki, Robert; Klewicka, Elzbieta

    2004-02-01

    Probiotic lactic acid bacteria were grown on erythritol, xylitol, sorbitol or lactitol and produced various derivatives: gal-erythritol, gal-xylitol, and gal-sorbitol as prebiotics. Galactosyl derivatives of erythritol, xylitol and sorbitol were metabolised by Lactobacillus spp. This resulted in their antagonistic activity against the test microflora. No activity was observed in the presence of xylitol and erythritol. Gal-sorbitol obtained by enzymatic transglycosylation from lactose had the same abilities of inducing the antagonistic activity of lactic acid bacteria that lactitol had. PMID:15055768

  1. Molecular cloning of a Pinguiochrysis pyriformis oleate-specific microsomal Δ12-fatty acid desaturase and functional analysis in yeasts and thraustochytrids.

    PubMed

    Matsuda, Takanori; Sakaguchi, Keishi; Kobayashi, Takumi; Abe, Eriko; Kurano, Norihide; Sato, Akira; Okita, Yuji; Sugimoto, Shinichi; Hama, Yoichiro; Hayashi, Masahiro; Okino, Nozomu; Ito, Makoto

    2011-10-01

    We isolated a putative desaturase gene from a marine alga, Pinguiochrysis pyriformis MBIC 10872, which is capable of accumulating eicosapentaenoic acid (C20:5(Δ5,8,11,14,17)). The gene possessed an open reading frame of 1,314 bp encoding a putative 437 amino acid residues showing high sequence identity (37-48%) with fungal and nematode Δ12-fatty acid desaturases. Yeast cells transformed with the gene converted endogenous oleic acid (C18:1(Δ9)) to linoleic acid (C18:2(Δ9,12)). However, no double bonds were introduced into other endogenous fatty acids or exogenously added fatty acids. Flag-tagged enzyme was recovered in the micosome fraction when expressed in yeast cells. To express the gene in thraustochytrids, a construct driven by the thraustochytrid-derived ubiquitin promoter was used. Interestingly, exogenously added oleic acid was converted to linoleic acid in the gene transformants but not mock transformants of Aurantiochytrium limacinum mh0186. These results clearly indicate that the gene encodes a microsomal Δ12-fatty acid desaturase and was expressed functionally in not only yeasts but also thraustochytrids. This is the first report describing the heterozygous expression of a fatty acid desaturase in thraustochytrids, and could facilitate a genetic approach towards fatty acid synthesis in thraustochytrids which are expected to be an alternative source of polyunsaturated fatty acids. PMID:21705343

  2. Enhanced α-ketoglutaric acid production and recovery in Yarrowia lipolytica yeast by effective pH controlling.

    PubMed

    Morgunov, Igor G; Kamzolova, Svetlana V; Samoilenko, Vladimir A

    2013-10-01

    The replacement of chemical synthesis by environmentally friendly energy-efficient technologies for production of valuable metabolites is a principal strategy of developing biotechnological industry all over the world. In the present study, we develop a method for α-ketoglutaric acid (KGA) production from rapeseed oil with the use of Yarrowia lipolytica yeast. Sixty strains of Y. lipolytica yeasts were tested for their ability to produce KGA, and the strain Y. lipolytica 212 (Y. lipolytica VKM Y-2412) was selected as a promising KGA producer. Using a three-stage pH controlling, in which pH was 4.5 in the growth phase, then since 72 to 144 h, pH was maintained at 3.5 and in the later phase of acid production, the titration by KOH was switch off, selected strain produced 106.5 g l(-1) of KGA with mass yield of 0.95 g g(-1). KGA in the form of monopotassium salt was isolated from the culture broth and purified. The isolation procedure involved separation of biomass, extraction of residual triglycerides, filtrate bleaching, and acidification with mineral acid (to pH 2.8-3.4), concentration, precipitation of mineral salts, and crystallization of the product. The purity of KGA isolated from the culture filtrate reached 99.1 %. PMID:23948727

  3. Nucleic acid fluorochromes and flow cytometry prove useful in assessing the effect of chlorination on drinking water bacteria.

    PubMed

    Phe, Meng-Huot; Dossot, Manuel; Guilloteau, Hélène; Block, Jean-Claude

    2005-09-01

    Flow cytometry (FCM), combined with staining using two fluorochromes (propidium iodide, PI, or SYBR Green II RNA gel stain, SYBR-II), was used to assess nucleic acid injuries to chlorinated drinking water bacteria. Highly fluorescent SYBR-II-stained bacteria were converted to bacteria with low fluorescence after chlorination. PI staining of bacteria exposed to different doses of chlorine showed membrane permeabilisation ([Cl2] < 0.2 mg L(-1)) and nucleic acid damage at higher doses ([Cl2] > 0.3 mg L(-1)). Above a threshold dose (between 1.5 and 3 mg Cl2 L(-1)), nucleic acids appeared severely damaged and incapable of being stained by PI or SYBR-II. These results constitute evidence that FCM is a promising tool for assessing drinking water bacteria injuries and for controlling chlorine disinfection efficiency much more rapidly than the standard sensitive but time-consuming heterotrophic plate count method. PMID:16081129

  4. SFH2 regulates fatty acid synthase activity in the yeast Saccharomyces cerevisiae and is critical to prevent saturated fatty acid accumulation in response to haem and oleic acid depletion.

    PubMed

    Desfougères, Thomas; Ferreira, Thierry; Bergès, Thierry; Régnacq, Matthieu

    2008-01-01

    The yeast Saccharomyces cerevisiae is a facultative anaerobic organism. Under anaerobiosis, sustained growth relies on the presence of exogenously supplied unsaturated fatty acids and ergosterol that yeast is unable to synthesize in the absence of oxygen or upon haem depletion. In the absence of exogenous supplementation with unsaturated fatty acid, a net accumulation of SFA (saturated fatty acid) is observed that induces significant modification of phospholipid profile [Ferreira, Régnacq, Alimardani, Moreau-Vauzelle and Bergès (2004) Biochem. J. 378, 899-908]. In the present paper, we focus on the role of SFH2/CSR1, a hypoxic gene related to SEC14 and its involvement in lipid metabolism upon haem depletion in the absence of oleic acid supplementation. We observed that inactivation of SFH2 results in enhanced accumulation of SFA and phospholipid metabolism alterations. It results in premature growth arrest and leads to an exacerbated sensitivity to exogenous SFA. This phenotype is suppressed in the presence of exogenous oleic acid, or by a controlled expression of FAS1, one of the two genes encoding FAS. We present several lines of evidence to suggest that Sfh2p and oleic acid regulate SFA synthase in yeast at different levels: whereas oleic acid acts on FAS2 at the transcriptional level, we show that Sfh2p inhibits fatty acid synthase activity in response to haem depletion. PMID:17803462

  5. Isolation and Characterization of Methanesulfonic Acid-Degrading Bacteria from the Marine Environment

    PubMed Central

    Thompson, A. S.; Owens, N.; Murrell, J. C.

    1995-01-01

    Two methylotrophic bacterial strains, TR3 and PSCH4, capable of growth on methanesulfonic acid as the sole carbon source were isolated from the marine environment. Methanesulfonic acid metabolism in these strains was initiated by an inducible NADH-dependent monooxygenase, which cleaved methanesulfonic acid into formaldehyde and sulfite. The presence of hydroxypyruvate reductase and the absence of ribulose monophosphate-dependent hexulose monophosphate synthase indicated the presence of the serine pathway for formaldehyde assimilation. Cell suspensions of bacteria grown on methanesulfonic acid completely oxidized methanesulfonic acid to carbon dioxide and sulfite with a methanesulfonic acid/oxygen stoichiometry of 1.0:2.0. Oxygen electrode-substrate studies indicated the dissimilation of formaldehyde to formate and carbon dioxide for energy generation. Carbon dioxide was not fixed by ribulose bisphosphate carboxylase. It was shown that methanol is not an intermediate in methanesulfonic acid metabolism, although these strains grew on methanol and other one-carbon compounds, as well as a variety of heterotrophic carbon sources. These two novel marine facultative methylotrophs have the ability to mineralize methanesulfonic acid and may play a role in the cycling of global organic sulfur. PMID:16535055

  6. Antagonistic Characteristics Against Food-borne Pathogenic Bacteria of Lactic Acid Bacteria and Bifidobacteria Isolated from Feces of Healthy Thai Infants

    PubMed Central

    Uraipan, Supansa; Hongpattarakere, Tipparat

    2015-01-01

    Background: Food-borne pathogens are among the most significant problems in maintaining the health of people. Many probiotics have been widely reported to alleviate and protect against gastrointestinal infections through antibacterial secretion. However, the majority of them cannot always play antagonistic roles under gut conditions. Probiotic bacteria of human origin must possess other protective mechanisms to survive, out-compete intestinal flora and to successfully establish in their new host at a significant level. Objectives: Probiotic characteristics of Lactic Acid Bacteria (LAB) and bifidobacteria isolated from the feces of Thai infants were primarily investigated in terms of gastric acid and bile resistances, antibacterial activity and mucin adhesion ability. Antagonistic interaction through secretion of antibacterial compounds and competitive exclusion against food-borne pathogens were also evaluated. Materials and Methods: Culturable LAB and bifidobacteria were isolated from feces of Thai infants. Their ability to withstand gastric acid and bile were then evaluated. Acid and bile salt tolerant LAB and bifidobacteria were identified. They were then further assessed according to their antagonistic interactions through antibacterial secretion, mucin adhesion and competitive mucin adhesion against various food-borne pathogenic bacteria. Results: Gastric acid and bile tolerant LAB and bifidobacteria isolated from healthy infant feces were identified and selected according to their antagonistic interaction against various food-borne pathogenic bacteria. These antagonistic probiotics included four strains of Lactobacillus rhamnosus, two strains of L. casei, five strains of L. plantarum, two strains of Bifidobacterium longum subsp. longum and three strains of B. bifidum. All strains of the selected LAB inhibited all pathogenic bacteria tested through antibacterial secretion, while bifidobacteria showed high level of competitive exclusion against the pathogenic

  7. Comparative chemotaxonomic studies of mycolic acid-free coryneform bacteria of human origin.

    PubMed

    Barreau, C; Bimet, F; Kiredjian, M; Rouillon, N; Bizet, C

    1993-08-01

    Forty-two clinical isolates were classified as Corynebacterium minutissimum, Corynebacterium striatum, and Corynebacterium CDC group I by the API Coryne system. The chemotaxonomic characteristics of the isolates were determined by thin-layer chromatographic analysis. Twenty-six isolates were found to have a type IV cell wall (meso-di-aminopimelic acid arabinose, galactose) but did not contain mycolic acids. These 26 isolates shared chemotaxonomic characteristics with those of mycolic acid-free reference strains (including the Corynebacterium amycolatum NCFB 2768 type strain, "Corynebacterium asperum," and coryneform CDC groups I2 and F2). The total protein profiles of the isolates determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were similar to each other and to that of the C. amycolatum type strain. The profiles of the reference strains "Corynebacterium asperum" (CIP 100836, CIP 80.54, CIP 79.37, CIP 52.13), coryneform bacteria CDC groups I2 and F2 (CDC F5771, F5890, G723, G1970), and C. amycolatum were closely related. Thus, the mycolic acid-negative strains with a chemotype IV wall may belong to a single taxon. DNA hybridization studies could confirm this hypothesis. The present study shows the importance of chemotaxonomic analysis for verifying strain identifications and completing results from biochemical tests, particularly for coryneform bacteria. PMID:8370733

  8. Comparative chemotaxonomic studies of mycolic acid-free coryneform bacteria of human origin.

    PubMed Central

    Barreau, C; Bimet, F; Kiredjian, M; Rouillon, N; Bizet, C

    1993-01-01

    Forty-two clinical isolates were classified as Corynebacterium minutissimum, Corynebacterium striatum, and Corynebacterium CDC group I by the API Coryne system. The chemotaxonomic characteristics of the isolates were determined by thin-layer chromatographic analysis. Twenty-six isolates were found to have a type IV cell wall (meso-di-aminopimelic acid arabinose, galactose) but did not contain mycolic acids. These 26 isolates shared chemotaxonomic characteristics with those of mycolic acid-free reference strains (including the Corynebacterium amycolatum NCFB 2768 type strain, "Corynebacterium asperum," and coryneform CDC groups I2 and F2). The total protein profiles of the isolates determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were similar to each other and to that of the C. amycolatum type strain. The profiles of the reference strains "Corynebacterium asperum" (CIP 100836, CIP 80.54, CIP 79.37, CIP 52.13), coryneform bacteria CDC groups I2 and F2 (CDC F5771, F5890, G723, G1970), and C. amycolatum were closely related. Thus, the mycolic acid-negative strains with a chemotype IV wall may belong to a single taxon. DNA hybridization studies could confirm this hypothesis. The present study shows the importance of chemotaxonomic analysis for verifying strain identifications and completing results from biochemical tests, particularly for coryneform bacteria. Images PMID:8370733

  9. Population dynamics of acetic acid bacteria during traditional wine vinegar production.

    PubMed

    Vegas, Carlos; Mateo, Estibaliz; González, Angel; Jara, Carla; Guillamón, José Manuel; Poblet, Montse; Torija, Ma Jesús; Mas, Albert

    2010-03-31

    The population dynamics of acetic acid bacteria in traditional vinegar production was determined in two independent vinegar plants at both the species and strain level. The effect of barrels made of four different woods upon the population dynamics was also determined. Acetic acid bacteria were isolated on solid media and the species were identified by RFLP-PCR of 16S rRNA genes and confirmed by 16S rRNA gene sequencing, while strains were typed by ERIC-PCR and (GTG)(5)-rep-PCR. The most widely isolated species was Acetobacter pasteurianus, which accounted for 100% of all the isolates during most of the acetification. Gluconacetobacter europaeus only appeared at any notable level at the end of the process in oak barrels from one vinegar plant. The various A. pasteurianus strains showed a clear succession as the concentration of acetic acid increased. In both vinegar plants the relative dominance of different strains was modified as the concentrations of acetic acid increased, and strain diversity tended to reduce at the end of the process. PMID:20117853

  10. Size-Dependent Toxicity of Silver Nanoparticles to Bacteria, Yeast, Algae, Crustaceans and Mammalian Cells In Vitro

    PubMed Central

    Ivask, Angela; Kurvet, Imbi; Kasemets, Kaja; Blinova, Irina; Aruoja, Villem; Suppi, Sandra; Vija, Heiki; Käkinen, Aleksandr; Titma, Tiina; Heinlaan, Margit; Visnapuu, Meeri; Koller, Dagmar; Kisand, Vambola; Kahru, Anne

    2014-01-01

    The concept of nanotechnologies is based on size-dependent properties of particles in the 1–100 nm range. However, the relation between the particle size and biological effects is still unclear. The aim of the current paper was to generate and analyse a homogenous set of experimental toxicity data on Ag nanoparticles (Ag NPs) of similar coating (citrate) but of 5 different primary sizes (10, 20, 40, 60 and 80 nm) to different types of organisms/cells commonly used in toxicity assays: bacterial, yeast and algal cells, crustaceans and mammalian cells in vitro. When possible, the assays were conducted in ultrapure water to minimise the effect of medium components on silver speciation. The toxic effects of NPs to different organisms varied about two orders of magnitude, being the lowest (∼0.1 mg Ag/L) for crustaceans and algae and the highest (∼26 mg Ag/L) for mammalian cells. To quantify the role of Ag ions in the toxicity of Ag NPs, we normalized the EC50 values to Ag ions that dissolved from the NPs. The analysis showed that the toxicity of 20–80 nm Ag NPs could fully be explained by released Ag ions whereas 10 nm Ag NPs proved more toxic than predicted. Using E. coli Ag-biosensor, we demonstrated that 10 nm Ag NPs were more bioavailable to E. coli than silver salt (AgNO3). Thus, one may infer that 10 nm Ag NPs had more efficient cell-particle contact resulting in higher intracellular bioavailability of silver than in case of bigger NPs. Although the latter conclusion is initially based on one test organism, it may lead to an explanation for “size-dependent“ biological effects of silver NPs. This study, for the first time, investigated the size-dependent toxic effects of a well-characterized library of Ag NPs to several microbial species, protozoans, algae, crustaceans and mammalian cells in vitro. PMID:25048192

  11. Zebrafish gut colonization by mCherry-labelled lactic acid bacteria.

    PubMed

    Russo, Pasquale; Iturria, Iñaki; Mohedano, Maria Luz; Caggianiello, Graziano; Rainieri, Sandra; Fiocco, Daniela; Angel Pardo, Miguel; López, Paloma; Spano, Giuseppe

    2015-04-01

    A critical feature of probiotic microorganisms is their ability to colonize the intestine of the host. Although the microbial potential to adhere to the human gut lumen has been investigated in in vitro models, there is still much to discover about their in vivo behaviour. Zebrafish is a vertebrate model that is being widely used to investigate various biological processes shared with humans. In this work, we report on the use of the zebrafish model to investigate the in vivo colonization ability of previously characterized probiotic lactic acid bacteria. Lactobacillus plantarum Lp90, L. plantarum B2 and Lactobacillus fermentum PBCC11.5 were fluorescently tagged by transfer of the pRCR12 plasmid, which encodes the mCherry protein and which was constructed in this work. The recombinant bacteria were used to infect germ-free zebrafish larvae. After removal of bacteria, the colonization ability of the strains was monitored until 3 days post-infection by using a fluorescence stereomicroscope. The results indicated differential adhesion capabilities among the strains. Interestingly, a displacement of bacteria from the medium to the posterior intestinal tract was observed as a function of time that suggested a transient colonization by probiotics. Based on fluorescence observation, L. plantarum strains exhibited a more robust adhesion capability. In conclusion, the use of pRCR12 plasmid for labelling Lactobacillus strains provides a powerful and very efficient tool to monitor the in vivo colonization in zebrafish larvae and to investigate the adhesion ability of probiotic microorganisms. PMID:25586576

  12. Phylogenetic analysis of antimicrobial lactic acid bacteria from farmed seabass Dicentrarchus labrax.

    PubMed

    Bourouni, Ouissal Chahad; El Bour, Monia; Calo-Mata, Pilar; Mraouna, Radhia; Abedellatif, Boudabous; Barros-Velàzquez, Jorge

    2012-04-01

    The use of lactic acid bacteria (LAB) in the prevention or reduction of fish diseases is receiving increasing attention. In the present study, 47 LAB strains were isolated from farmed seabass ( Dicentrarchus labrax ) and were phenotypically and phylogenetically analysed by 16S rDNA and randomly amplified polymorphic DNA - polymerase chain reaction (RAPD-PCR). Their antimicrobial effect was tested in vitro against a wide variety of pathogenic and spoilage bacteria. Most of the strains isolated were enterococci belonging to the following species: Enterococcus faecium (59%), Enterococcus faecalis (21%), Enterococcus sanguinicola (4 strains), Enterococcus mundtii (1 strain), Enterococcus pseudoavium (1 strain), and Lactococcus lactis (1 strain). An Aerococcus viridans strain was also isolated. The survey of their antimicrobial susceptibility showed that all isolates were sensitive to vancomycin and exhibited resistance to between 4 and 10 other antibiotics relevant for therapy in human and animal medicine. Different patterns of resistance were noted for skin and intestines isolates. More than 69% (32 strains) of the isolates inhibited the growth of the majority of pathogenic and spoilage bacteria tested, including Listeria monocytogenes, Staphylococcus aureus, Aeromonas hydrophila, Aeromonas salmonicida, Vibrio anguillarum, and Carnobacterium sp. To our knowledge, this is the first report of bioactive enterococcal species isolated from seabass that could potentially inhibit the undesirable bacteria found in food systems. PMID:22439634

  13. Promotion of Intestinal Epithelial Cell Turnover by Commensal Bacteria: Role of Short-Chain Fatty Acids.

    PubMed

    Park, Jung-Ha; Kotani, Takenori; Konno, Tasuku; Setiawan, Jajar; Kitamura, Yasuaki; Imada, Shinya; Usui, Yutaro; Hatano, Naoya; Shinohara, Masakazu; Saito, Yasuyuki; Murata, Yoji; Matozaki, Takashi

    2016-01-01

    The life span of intestinal epithelial cells (IECs) is short (3-5 days), and its regulation is thought to be important for homeostasis of the intestinal epithelium. We have now investigated the role of commensal bacteria in regulation of IEC turnover in the small intestine. The proliferative activity of IECs in intestinal crypts as well as the migration of these cells along the crypt-villus axis were markedly attenuated both in germ-free mice and in specific pathogen-free (SPF) mice treated with a mixture of antibiotics, with antibiotics selective for Gram-positive bacteria being most effective in this regard. Oral administration of chloroform-treated feces of SPF mice to germ-free mice resulted in a marked increase in IEC turnover, suggesting that spore-forming Gram-positive bacteria contribute to this effect. Oral administration of short-chain fatty acids (SCFAs) as bacterial fermentation products also restored the turnover of IECs in antibiotic-treated SPF mice as well as promoted the development of intestinal organoids in vitro. Antibiotic treatment reduced the phosphorylation levels of ERK, ribosomal protein S6, and STAT3 in IECs of SPF mice. Our results thus suggest that Gram-positive commensal bacteria are a major determinant of IEC turnover, and that their stimulatory effect is mediated by SCFAs. PMID:27232601

  14. Promotion of Intestinal Epithelial Cell Turnover by Commensal Bacteria: Role of Short-Chain Fatty Acids

    PubMed Central

    Park, Jung-ha; Kotani, Takenori; Konno, Tasuku; Setiawan, Jajar; Kitamura, Yasuaki; Imada, Shinya; Usui, Yutaro; Hatano, Naoya; Shinohara, Masakazu; Saito, Yasuyuki; Murata, Yoji; Matozaki, Takashi

    2016-01-01

    The life span of intestinal epithelial cells (IECs) is short (3–5 days), and its regulation is thought to be important for homeostasis of the intestinal epithelium. We have now investigated the role of commensal bacteria in regulation of IEC turnover in the small intestine. The proliferative activity of IECs in intestinal crypts as well as the migration of these cells along the crypt-villus axis were markedly attenuated both in germ-free mice and in specific pathogen–free (SPF) mice treated with a mixture of antibiotics, with antibiotics selective for Gram-positive bacteria being most effective in this regard. Oral administration of chloroform-treated feces of SPF mice to germ-free mice resulted in a marked increase in IEC turnover, suggesting that spore-forming Gram-positive bacteria contribute to this effect. Oral administration of short-chain fatty acids (SCFAs) as bacterial fermentation products also restored the turnover of IECs in antibiotic-treated SPF mice as well as promoted the development of intestinal organoids in vitro. Antibiotic treatment reduced the phosphorylation levels of ERK, ribosomal protein S6, and STAT3 in IECs of SPF mice. Our results thus suggest that Gram-positive commensal bacteria are a major determinant of IEC turnover, and that their stimulatory effect is mediated by SCFAs. PMID:27232601

  15. Current status and emerging role of glutathione in food grade lactic acid bacteria

    PubMed Central

    2012-01-01

    Lactic acid bacteria (LAB) have taken centre stage in perspectives of modern fermented food industry and probiotic based therapeutics. These bacteria encounter various stress conditions during industrial processing or in the gastrointestinal environment. Such conditions are overcome by complex molecular assemblies capable of synthesizing and/or metabolizing molecules that play a specific role in stress adaptation. Thiols are important class of molecules which contribute towards stress management in cell. Glutathione, a low molecular weight thiol antioxidant distributed widely in eukaryotes and Gram negative organisms, is present sporadically in Gram positive bacteria. However, new insights on its occurrence and role in the latter group are coming to light. Some LAB and closely related Gram positive organisms are proposed to possess glutathione synthesis and/or utilization machinery. Also, supplementation of glutathione in food grade LAB is gaining attention for its role in stress protection and as a nutrient and sulfur source. Owing to the immense benefits of glutathione, its release by probiotic bacteria could also find important applications in health improvement. This review presents our current understanding about the status of glutathione and its role as an exogenously added molecule in food grade LAB and closely related organisms. PMID:22920585

  16. Interactions of the cell-wall glycopolymers of lactic acid bacteria with their bacteriophages

    PubMed Central

    Chapot-Chartier, Marie-Pierre

    2014-01-01

    Lactic acid bacteria (LAB) are Gram positive bacteria widely used in the production of fermented food in particular cheese and yoghurts. Bacteriophage infections during fermentation processes have been for many years a major industrial concern and have stimulated numerous research efforts. Better understanding of the molecular mechanisms of bacteriophage interactions with their host bacteria is required for the development of efficient strategies to fight against infections. The bacterial cell wall plays key roles in these interactions. First, bacteriophages must adsorb at the bacterial surface through specific interactions with receptors that are cell wall components. At next step, phages must overcome the barrier constituted by cell wall peptidoglycan (PG) to inject DNA inside bacterial cell. Also at the end of the infection cycle, phages synthesize endolysins able to hydrolyze PG and lyse bacterial cells to release phage progeny. In the last decade, concomitant development of genomics and structural analysis of cell wall components allowed considerable advances in the knowledge of their structure and function in several model LAB. Here, we describe the present knowledge on the structure of the cell wall glycopolymers of the best characterized LAB emphasizing their structural variations and we present the available data regarding their role in bacteria-phage specific interactions at the different steps of the infection cycle. PMID:24904550

  17. Impairment of cellulose- and cellobiose-degrading soil Bacteria by two acidic herbicides.

    PubMed

    Schellenberger, Stefanie; Drake, Harold L; Kolb, Steffen

    2012-02-01

    Herbicides have the potential to impair the metabolism of soil microorganisms. The current study addressed the toxic effect of bentazon and 4-chloro-2-methylphenoxyacetic acid on aerobic and anaerobic Bacteria that are involved in cellulose and cellobiose degradation in an agricultural soil. Aerobic saccharide degradation was reduced at concentrations of herbicides above environmental values. Microbial processes (e.g. fermentations, ferric iron reduction) that were linked to anaerobic cellulose and cellobiose degradation were reduced in the presence of both herbicides at concentrations above and at those that occur in crop field soil. 16S rRNA gene transcript numbers of total Bacteria, and selected bacterial taxa (Clostridia [Group I], Planctomycetaceae, and two uncultivated taxa of Bacteroidetes) decreased more in anoxic than in oxic cellulose-supplemented soil microcosms in the presence of both herbicides. Collectively, the results suggested that the metabolism of anaerobic cellulose-degrading Bacteria was impaired by typical in situ herbicide concentrations, whereas in situ concentrations did not impair metabolism of aerobic cellulose- and cellobiose-degrading soil Bacteria. PMID:22098368

  18. Aflatoxin B1 binding by dairy strains of lactic acid bacteria and bifidobacteria.

    PubMed

    Peltonen, K; el-Nezami, H; Haskard, C; Ahokas, J; Salminen, S

    2001-10-01

    Various food commodities including dairy products may be contaminated with aflatoxins, which, even in small quantities, have detrimental effects on human and animal health. Several microorganisms have been reported to bind or degrade aflatoxins in foods and feeds. This study assessed the binding of aflatoxin B1 (AFB1) from contaminated solution by 20 strains of lactic acid bacteria and bifidobacteria. The selected strains are used in the food industry and comprised 12 Lactobacillus, five Bifidobacterium, and three Lactococcus strains. Bacteria and AFB1 were incubated (24 h, +37 degrees C) and the amount of unbound AFB1 was quantitated by HPLC. Between 5.6 and 59.7% AFB1 was bound from solution by these strains. Two Lactobacillus amylovorus strains and one Lactobacillus rhamnosus strain removed more than 50% AFB1 and were selected for further study. Bacterial binding of AFB1 by these strains was rapid, and more than 50% AFB1 was bound throughout a 72-h incubation period. Binding was reversible, and AFB1 was released by repeated aqueous washes. These findings further support the ability of specific strains of lactic acid bacteria to bind selected dietary contaminants. PMID:11699445

  19. Screening of species-specific lactic acid bacteria for veal calves multi-strain probiotic adjuncts.

    PubMed

    Ripamonti, Barbara; Agazzi, Alessandro; Bersani, Carla; De Dea, Paola; Pecorini, Chiara; Pirani, Silvia; Rebucci, Raffaella; Savoini, Giovanni; Stella, Simone; Stenico, Alberta; Tirloni, Erica; Domeneghini, Cinzia

    2011-06-01

    The selection of promising specific species of lactic acid bacteria with potential probiotic characteristics is of particular interest in producing multi species-specific probiotic adjuncts in veal calves rearing. The aim of the present work was to select and evaluate in vitro the functional activity of lactic acid bacteria, Bifidobacterium longum and Bacillus coagulans strains isolated from veal calves in order to assess their potential use as multi species-specific probiotics for veal calves. For this purpose, bacterial strains isolated from faeces collected from 40 healthy 50-day-calves, were identified by RiboPrinter and 16s rRNA gene sequence. The most frequent strains belonged to the species B. longum, Streptococcus bovis, Lactobacillus animalis and Streptococcus macedonicus. Among these, 7 strains were chosen for testing their probiotic characteristics in vitro. Three strains, namely L. animalis SB310, Lactobacillus paracasei subsp. paracasei SB137 and B. coagulans SB117 showed varying individual but promising capabilities to survive in the gastrointestinal tract, to adhere, to produce antimicrobial compounds. These three selected species-specific bacteria demonstrated in vitro, both singularly and mixed, the functional properties needed for their use as potential probiotics in veal calves. PMID:21619939

  20. Influence of Perfluorooctanoic Acid on the Transport and Deposition Behaviors of Bacteria in Quartz Sand.

    PubMed

    Wu, Dan; Tong, Meiping; Kim, Hyunjung

    2016-03-01

    The significance of perfluorooctanoic acid (PFOA) on the transport and deposition behaviors of bacteria (Gram-negative Escherichia coli and Gram-positive Bacillus subtilis) in quartz sand is examined in both NaCl and CaCl2 solutions at pH 5.6 by comparing both breakthrough curves and retained profiles with PFOA in solutions versus those without PFOA. All test conditions are found to be highly unfavorable for cell deposition regardless of the presence of PFOA; however, 7%-46% cell deposition is observed depending on the conditions. The cell deposition may be attributed to micro- or nanoscale roughness and/or to chemical heterogeneity of the sand surface. The results show that, under all examined conditions, PFOA in suspensions increases cell transport and decreases cell deposition in porous media regardless of cell type, presence or absence of extracellular polymeric substances, ionic strength, and ion valence. We find that the additional repulsion between bacteria and quartz sand caused by both acid-base interaction and steric repulsion as well as the competition for deposition sites on quartz sand surfaces by PFOA are responsible for the enhanced transport and decreased deposition of bacteria with PFOA in solutions. PMID:26866280

  1. The activity of ferulic and gallic acids in biofilm prevention and control of pathogenic bacteria.

    PubMed

    Borges, Anabela; Saavedra, Maria J; Simões, Manuel

    2012-01-01

    The activity of two phenolic acids, gallic acid (GA) and ferulic acid (FA) at 1000 μg ml(-1), was evaluated on the prevention and control of biofilms formed by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. In addition, the effect of the two phenolic acids was tested on planktonic cell susceptibility, bacterial motility and adhesion. Biofilm prevention and control were tested using a microtiter plate assay and the effect of the phenolic acids was assessed on biofilm mass (crystal violet staining) and on the quantification of metabolic activity (alamar blue assay). The minimum bactericidal concentration for P. aeruginosa was 500 μg ml(-1) (for both phenolic acids), whilst for E. coli it was 2500 μg ml(-1) (FA) and 5000 μg ml(-1) (GA), for L. monocytogenes it was >5000 μg ml(-1) (for both phenolic acids), and for S. aureus it was 5000 μg ml(-1) (FA) and >5000 μg ml(-1) (GA). GA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. FA caused total inhibition of swimming (L. monocytogenes) and swarming (L. monocytogenes and E. coli) motilities. Colony spreading of S. aureus was completely inhibited by FA. The interference of GA and FA with bacterial adhesion was evaluated by the determination of the free energy of adhesion. Adhesion was less favorable when the bacteria were exposed to GA (P. aeruginosa, S. aureus and L. monocytogenes) and FA (P. aeruginosa and S. aureus). Both phenolics had preventive action on biofilm formation and showed a higher potential to reduce the mass of biofilms formed by the Gram-negative bacteria. GA and FA promoted reductions in biofilm activity >70% for all the biofilms tested. The two phenolic acids demonstrated the potential to inhibit bacterial motility and to prevent and control biofilms of four important human pathogenic bacteria. This study also emphasizes the potential of phytochemicals as an emergent source of biofilm

  2. GFP Reporter Screens for the Engineering of Amino Acid Degrading Enzymes from Libraries Expressed in Bacteria

    PubMed Central

    Paley, Olga; Agnello, Giulia; Cantor, Jason; Yoo, Tae Hyun; Georgiou, George; Stone, Everett

    2014-01-01

    There is significant interest in engineering human amino acid degrading enzymes as non-immunogenic chemotherapeutic agents. We describe a high-throughput fluorescence activated cell sorting (FACS) assay for detecting the catalytic activity of amino acid degrading enzymes in bacteria, at the single cell level. This assay relies on coupling the synthesis of the GFP reporter to the catalytic activity of the desired amino acid degrading enzyme in an appropriate E. coli genetic background. The method described here allows facile screening of much larger libraries (106–107) than was previously possible. We demonstrate the application of this technique in the screening of libraries of bacterial and human asparaginases and also for the catalytic optimization of an engineered human methionine gamma lyase. PMID:23423887

  3. Screening of potential probiotic lactic acid bacteria based on gastrointestinal properties and perfluorooctanoate toxicity.

    PubMed

    Xing, Jiali; Wang, Fan; Xu, Qi; Yin, Boxing; Fang, Dongsheng; Zhao, Jianxin; Zhang, Hao; Chen, Yong Q; Wang, Gang; Chen, Wei

    2016-08-01

    The consumption of lactic acid bacteria capable of binding or degrading food-borne carcinogens may reduce human exposure to these deleterious compounds. In this study, 25 Lactobacillus strains isolated from human, plant, or dairy environments were investigated for their potential probiotic capacity against perfluorooctanoate (PFOA) toxicity. The PFOA binding, tolerance ability, and acid and bile salt tolerance were investigated and assessed by principal component analysis. Additionally, the effect of different pH levels and binding times was assessed. These strains exhibited different degrees of PFOA binding; the strain with the highest PFOA binding capability was Lactobacillus plantarum CCFM738, which bound to 49.40 ± 1.5 % of available PFOA. This strain also exhibited relatively good cellular antioxidative properties, acid and bile salt tolerance, and adhesion to Caco-2 cells. This study suggests that L. plantarum CCFM738 could be used as a potential probiotic in food applications against PFOA toxicity. PMID:27094185

  4. Isolation of lactic acid bacteria from Malaysian foods and assessment of the isolates for industrial potential.

    PubMed

    Mohd Adnan, Ahmad Faris; Tan, Irene K P

    2007-05-01

    Two traditional fermented food 'tapai' (fermented tapioca) and 'tempoyak' (fermented durian flesh), chilli puree and fresh goat's milk were used as sources for the isolation of lactic acid bacteria (LAB). A total of 126 isolates were obtained and by sequential screening for catalase activity and Gram-staining, 55 were determined to be LAB out of which 16 were established to be homofermentative by the gel plug test. Seven isolates were identified by use of the API 50CHL kit and two lactobacilli strains and one lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The lactobacilli strains, both isolated from 'tapai', produced higher amounts of cells and lactic acid from glucose as compared to the lactococci strain isolated from fresh goat's milk. PMID:16872826

  5. Oil production by oleaginous yeasts using the hydrolysate from pretreatment of wheat straw with dilute sulfuric acid.

    PubMed

    Yu, Xiaochen; Zheng, Yubin; Dorgan, Kathleen M; Chen, Shulin

    2011-05-01

    This paper explores the use of the hydrolysate from the dilute sulfuric acid pretreatment of wheat straw for microbial oil production. The resulting hydrolysate was composed of pentoses (24.3g/L) and hexoses (4.9 g/L), along with some other degradation products, such as acetic acid, furfural, and hydroxymethylfurfural (HMF). Five oleaginous yeast strains, Cryptococcus curvatus, Rhodotorula glutinis, Rhodosporidium toruloides, Lipomyces starkeyi, and Yarrowia lipolytica, were evaluated by using this hydrolysate as substrates. The results showed that all of these strains could use the detoxified hydrolysate to produce lipids while except R. toruloides non-detoxified hydrolysate could also be used for the growth of all of the selective yeast strains. C. curvatus showed the highest lipid concentrations in medium on both the detoxified (4.2g/L) and non-detoxified (5.8 g/L) hydrolysates. And the inhibitory effect studies on C. curvatus indicated HMF had insignificant impacts at a concentration of up to 3g/L while furfural inhibited cell growth and lipid content by 72.0% and 62.0% at 1g/L, respectively. Our work demonstrates that lipid production is a promising alternative to utilize hemicellulosic sugars obtained during pretreatment of lignocellulosic materials. PMID:21463940

  6. Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications

    PubMed Central

    2014-01-01

    Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed. PMID:25186038

  7. Novel bacteriocins from lactic acid bacteria (LAB): various structures and applications.

    PubMed

    Perez, Rodney H; Zendo, Takeshi; Sonomoto, Kenji

    2014-08-29

    Bacteriocins are heat-stable ribosomally synthesized antimicrobial peptides produced by various bacteria, including food-grade lactic acid bacteria (LAB). These antimicrobial peptides have huge potential as both food preservatives, and as next-generation antibiotics targeting the multiple-drug resistant pathogens. The increasing number of reports of new bacteriocins with unique properties indicates that there is still a lot to learn about this family of peptide antibiotics. In this review, we highlight our system of fast tracking the discovery of novel bacteriocins, belonging to different classes, and isolated from various sources. This system employs molecular mass analysis of supernatant from the candidate strain, coupled with a statistical analysis of their antimicrobial spectra that can even discriminate novel variants of known bacteriocins. This review also discusses current updates regarding the structural characterization, mode of antimicrobial action, and biosynthetic mechanisms of various novel bacteriocins. Future perspectives and potential applications of these novel bacteriocins are also discussed. PMID:25186038

  8. Interaction of lactic acid bacteria with metal ions: opportunities for improving food safety and quality.

    PubMed

    Mrvčić, Jasna; Stanzer, Damir; Solić, Ema; Stehlik-Tomas, Vesna

    2012-09-01

    Certain species of lactic acid bacteria (LAB), as well as other microorganisms, can bind metal ions to their cells surface or transport and store them inside the cell. Due to this fact, over the past few years interactions of metal ions with LAB have been intensively investigated in order to develop the usage of these bacteria in new biotechnology processes in addition to their health and probiotic aspects. Preliminary studies in model aqueous solutions yielded LAB with high absorption potential for toxic and essential metal ions, which can be used for improving food safety and quality. This paper provides an overview of results obtained by LAB application in toxic metal ions removing from drinking water, food and human body, as well as production of functional foods and nutraceutics. The biosorption abilities of LAB towards metal ions are emphasized. The binding mechanisms, as well as the parameters influencing the passive and active uptake are analyzed. PMID:22806724

  9. Occurrence of Lactic Acid Bacteria During the Different Stages of Vinification and Conservation of Wines

    PubMed Central

    Lafon-Lafourcade, S.; Carre, E.; Ribéreau-Gayon, P.

    1983-01-01

    We showed that the growth of lactic acid bacteria during alcoholic fermentation depends on the composition of the must. We illustrated how the addition of sulfur dioxide to the must before fermentation and the temperature of storage both affect the growth of these bacteria in the wine. Whereas species of Lactobacillus and Leuconostoc mesenteroides were isolated from grapes and must, Leuconostoc oenos was the only species isolated after alcoholic fermentation. This organism was responsible for the malolactic fermentation. Isolates of this species varied in their ability to ferment pentoses and hexoses. The survival of Leuconostoc oenos in wines after malolactic fermentation depended on wine pH, alcohol concentration, SO2 concentration, and temperature of storage. PMID:16346401

  10. Lactic Acid Bacteria Inducing a Weak Interleukin-12 and Tumor Necrosis Factor Alpha Response in Human Dendritic Cells Inhibit Strongly Stimulating Lactic Acid Bacteria but Act Synergistically with Gram-Negative Bacteria

    PubMed Central

    Zeuthen, Louise Hjerrild; Christensen, Hanne Risager; Frøkiær, Hanne

    2006-01-01

    The development and maintenance of immune homeostasis indispensably depend on signals from the gut flora. Lactic acid bacteria (LAB), which are gram-positive (G+) organisms, are plausible significant players and have received much attention. Gram-negative (G−) commensals, such as members of the family Enterobacteriaceae, may, however, be immunomodulators that are as important as G+ organisms but tend to be overlooked. Dendritic cells (DCs) are crucial immune regulators, and therefore, the present study aimed at investigating differences among human gut flora-derived LAB and G− bacteria in their patterns of DC polarization. Human monocyte-derived DCs were exposed to UV-killed bacteria, and cytokine secretion and surface marker expression were analyzed. Profound differences in the DC polarization patterns were found among the strains. While strains of LAB varied greatly in their capacity to induce interleukin-12 (IL-12) and tumor necrosis factor alpha (TNF-α), G− strains were consistently weak IL-12 and TNF-α inducers. All strains induced significant amounts of IL-10, but G− bacteria were far more potent IL-10 inducers than LAB. Interestingly, we found that when weakly IL-12- and TNF-α-inducing LAB and strong IL-12- and TNF-α-inducing LAB were mixed, the weakly IL-12- and TNF-α-inducing LAB efficiently inhibited otherwise strong IL-12- and TNF-α-inducing LAB, yet when weakly IL-12- and TNF-α-inducing LAB were mixed with G− bacteria, they synergistically induced IL-12 and TNF-α. Furthermore, strong IL-12- and TNF-α-inducing LAB efficiently up-regulated surface markers (CD40, CD83, CD86, and HLA-DR), which were inhibited by weakly IL-12- and TNF-α-inducing LAB. All G− bacteria potently up-regulated surface markers; however, these markers were not inhibited by weakly IL-12- and TNF-α-inducing LAB. These much divergent DC stimulation patterns among intestinal bacteria, which encompass both antagonistic and synergistic relationships, support the

  11. Characteristics of lactic acid bacteria isolates and their effect on silage fermentation of fruit residues.

    PubMed

    Yang, Jinsong; Tan, Haisheng; Cai, Yimin

    2016-07-01

    The natural lactic acid bacteria (LAB) population, chemical composition, and silage fermentation of fruit residues were studied. Eighty-two strains of LAB were isolated from fruit residues such as banana leaf and stem, pineapple peel, and papaya peel. All strains were gram-positive and catalase-negative bacteria, and they were divided into 7 groups (A-G) according to morphological and biochemical characters. Strains in groups A to F were rods, and group G was cocci. Group F produced gas from glucose; other groups did not. Groups A to C and F formed dl-lactic acid, whereas groups D, E, and G formed l-lactic acid. Based on the 16S rRNA gene sequence and DNA-DNA hybridization analysis, groups A to G strains were identified as Lactobacillus plantarum (54.9% of the total isolates), Lactobacillus paraplantarum (3.6%), Lactobacillus nagelii (8.5%), Lactobacillus perolens (4.9%), Lactobacillus casei (11.0%), Lactobacillus fermentum (9.8%), and Enterococcus gallinarum (7.3%), respectively. Lactobacillus plantarum and Lactobacillus casei are the most frequently isolated from fruit residues as a dominant species, and they could grow at a lower pH conditions and produce more lactic acid than other isolates. Pineapple and papaya peels contained higher crude protein (11.5-13.8%) and water-soluble carbohydrate (16.8-22.4%), but lower acid detergent fiber contents (21.2 to 26.4%) than banana stems and leaves (8.2% crude protein, 42.8% acid detergent fiber, and 5.1% water-soluble carbohydrate). Compared with banana stem and leaf silages, the pineapple and papaya peel silages were well preserved with a lower pH and higher lactate content. The study suggests that the fruit residues contain excellent LAB species and abundant feed nutrients, and that they can be preserved as silage to be potential food resources for livestock. PMID:27108171

  12. Synthetic Teichoic Acid Conjugate Vaccine against Nosocomial Gram-Positive Bacteria

    PubMed Central

    Laverde, Diana; Wobser, Dominique; Romero-Saavedra, Felipe; Hogendorf, Wouter; van der Marel, Gijsbert; Berthold, Martin; Kropec, Andrea; Codee, Jeroen; Huebner, Johannes

    2014-01-01

    Lipoteichoic acids (LTA) are amphiphilic polymers that are important constituents of the cell wall of many Gram-positive bacteria. The chemical structures of LTA vary among organisms, albeit in the majority of Gram-positive bacteria the LTAs feature a common poly-1,3-(glycerolphosphate) backbone. Previously, the specificity of opsonic antibodies for this backbone present in some Gram-positive bacteria has been demonstrated, suggesting that this minimal structure may be sufficient for vaccine development. In the present work, we studied a well-defined synthetic LTA-fragment, which is able to inhibit opsonic killing of polyclonal rabbit sera raised against native LTA from Enterococcus faecalis 12030. This promising compound was conjugated with BSA and used to raise rabbit polyclonal antibodies. Subsequently, the opsonic activity of this serum was tested in an opsonophagocytic assay and specificity was confirmed by an opsonophagocytic inhibition assay. The conjugated LTA-fragment was able to induce specific opsonic antibodies that mediate killing of the clinical strains E. faecalis 12030, Enterococcus faecium E1162, and community-acquired Staphylococcus aureus strain MW2 (USA400). Prophylactic immunization with the teichoic acid conjugate and with the rabbit serum raised against this compound was evaluated in active and passive immunization studies in mice, and in an enterococcal endocarditis rat model. In all animal models, a statistically significant reduction of colony counts was observed indicating that the novel synthetic LTA-fragment conjugate is a promising vaccine candidate for active or passive immunotherapy against E. faecalis and other Gram-positive bacteria. PMID:25333799

  13. Antigenotoxic activity of lactic acid bacteria, prebiotics, and products of their fermentation against selected mutagens.

    PubMed

    Nowak, Adriana; Śliżewska, Katarzyna; Otlewska, Anna

    2015-12-01

    Dietary components such as lactic acid bacteria (LAB) and prebiotics can modulate the intestinal microbiota and are thought to be involved in the reduction of colorectal cancer risk. The presented study measured, using the comet assay, the antigenotoxic activity of both probiotic and non-probiotic LAB, as well as some prebiotics and the end-products of their fermentation, against fecal water (FW). The production of short chain fatty acids by the bacteria was quantified using HPLC. Seven out of the ten tested viable strains significantly decreased DNA damage induced by FW. The most effective of them were Lactobacillus mucosae 0988 and Bifidobacterium animalis ssp. lactis Bb-12, leading to a 76% and 80% decrease in genotoxicity, respectively. The end-products of fermentation of seven prebiotics by Lactobacillus casei DN 114-001 exhibited the strongest antigenotoxic activity against FW, with fermented inulin reducing genotoxicity by 75%. Among the tested bacteria, this strain produced the highest amounts of butyrate in the process of prebiotic fermentation, and especially from resistant dextrin (4.09 μM/mL). Fermented resistant dextrin improved DNA repair by 78% in cells pre-treated with 6.8 μM methylnitronitrosoguanidine (MNNG). Fermented inulin induced stronger DNA repair in cells pre-treated with mutagens (FW, 25 μM hydrogen peroxide, or MNNG) than non-fermented inulin, and the efficiency of DNA repair after 120 min of incubation decreased by 71%, 50% and 70%, respectively. The different degrees of genotoxicity inhibition observed for the various combinations of bacteria and prebiotics suggest that this effect may be attributable to carbohydrate type, SCFA yield, and the ratio of the end-products of prebiotic fermentation. PMID:26404012

  14. Efficacy of Locally Isolated Lactic Acid Bacteria Against Antibiotic-Resistant Uropathogens

    PubMed Central

    Manzoor, Asma; Ul-Haq, Ikram; Baig, Shahjhan; Qazi, Javed Iqbal; Seratlic, Sanja

    2016-01-01

    Background: Antibiotic resistance represents a serious global health threat to public health, so infections such as pneumonia and urinary tract infection (UTI) are becoming harder to treat. Therefore, it is necessary to develop an action plan to restrain the problem of antibiotic resistance. One approach in UTI control could be the use of lactobacilli because these indigenous inhabitants in human intestine have been found to play an important role in protecting the host from various infections. Objectives: We sought to check the efficacy of locally isolated Lactobacillus species to eradicate antibiotic-resistant pathogenic bacteria causing UTI. Materials and Methods: Lactic acid bacteria isolated from spoiled fruits and vegetables and grown in MRS medium were screened against multi-drug-resistant Candida albicans, Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Enterococcus fecalis. Results: Fifty-four lactic acid bacteria were isolated from spoiled fruits and vegetables, of which 11 Gram-positive and catalase-negative Lactobacillus isolates were identified by carbohydrate assimilation profiles as Lactobacillus acidophilus, L. paracasei, L. delbrueckii, L. casei, L. helveticus, L. brevis, L. salivarius, L. fermentum, L. rhamnosus, L. animalis, and L. plantarum. The latter organism had the highest abundance of all the samples, so its isolates were also verified through 16S rRNA gene sequencing. The isolated Lactobacilli were screened against multi-drug-resistant uropathogens, viz. C. albicans, P. aeruginosa, K. pneumoniae, E. fecalis, and E. coli. The growth inhibition zone (GIZ) was over 10 mm against all the uropathogenic test organisms, where L. fermentum and L. plantarum strains demonstrated remarkable inhibitory activities against E. coli and E. faecalis, with a GIZ up to 28 mm. The susceptibility test to 16 antibiotics showed multidrug resistance (3 to 5 antibiotics) among all the tested uropathogens. Conclusions: The obtained results

  15. Efficacy of microencapsulated lactic acid bacteria in Helicobater pylori eradication therapy

    PubMed Central

    Khalil, Maha A.; El-Sheekh, Mostafa M.; El-Adawi, Hala I.; El-Deeb, Nehal M.; Hussein, Mohamed Z.

    2015-01-01

    Background: Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in the effectiveness to exert health benefits for a patient. This study focuses on providing probiotic living cells with a physical barrier against adverse environmental conditions. Materials and Methods: Microencapsulation of the selected lactic acid bacteria (LAB) using chitosan and alginate was performed. Physical examination of the formulated LAB microcapsules was observed using phase contrast inverted microscope and scanning electron microscope (SEM). Finally, the survival of microencapsulated and noncapsulated bacteria was cheeked in the simulated human gastric tract (GT). The potential antimicrobial activity of the most potent microencapsulated LAB strain was in vivo evaluated in rabbit models. Results: Microencapsulated L. plantarum, L. acidophilus, and L. bulgaricus DSMZ 20080 were loaded with 1.03 × 1010 CFU viable bacteria/g, 1.9 × 1010 CFU viable bacteria/g, and 5.5 × 109 CFU viable bacteria/g, respectively. The survival of microencapsulated cells was significantly higher than that of the free cells after exposure to simulated gastric juice (SGJ) at pH 2. Additionally, in simulated small intestine juice (SSJ), larger amounts of the selected LAB cells were found, whereas in simulated colon juice (SCJ), the released LAB reached the maximum counts. In vivo results pointed out that an 8-week supplementation with a triple therapy of a microencapsulated L. plantarum, L. acidophilus, and L. bulgaricus DSMZ 20080 might be able to reduce H. pylori. Conclusion: Microencapsulated probiotics could possibly compete with and downregulate H. pylori infection in humans. PMID:26929759

  16. Application of antimicrobial-producing lactic acid bacteria to control pathogens in ready-to-use vegetables.

    PubMed

    Vescovo, M; Torriani, S; Orsi, C; Macchiarolo, F; Scolari, G

    1996-08-01

    Five psychrotrophic strains of lactic acid bacteria (Lactobacillus casei, Lact. plantarum and Pediococcus spp.) were isolated from 22 samples of commercial salads. These strains were shown to inhibit Aeromonas hydrophila, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus on MRS agar, in salads and in juice prepared from vegetable salads. Lactobacillus casei IMPCLC34 was most effective in reducing total mesophilic bacteria and the coliform group; Aer. hydrophila, Salm. typhimurium and Staph. aureus disappeared after 6 d of storage, while the counts for L. monocytogenes remained constant. The potential application of antimicrobial-producing lactic acid bacteria as biopreservatives of ready-to-use vegetables is suggested. PMID:8760320

  17. Evidence of Two Functionally Distinct Ornithine Decarboxylation Systems in Lactic Acid Bacteria

    PubMed Central

    Romano, Andrea; Trip, Hein; Lonvaud-Funel, Aline; Lolkema, Juke S.

    2012-01-01

    Biogenic amines are low-molecular-weight organic bases whose presence in food can result in health problems. The biosynthesis of biogenic amines in fermented foods mostly proceeds through amino acid decarboxylation carried out by lactic acid bacteria (LAB), but not all systems leading to biogenic amine production by LAB have been thoroughly characterized. Here, putative ornithine decarboxylation pathways consisting of a putative ornithine decarboxylase and an amino acid transporter were identified in LAB by strain collection screening and database searches. The decarboxylases were produced in heterologous hosts and purified and characterized in vitro, whereas transporters were heterologously expressed in Lactococcus lactis and functionally characterized in vivo. Amino acid decarboxylation by whole cells of the original hosts was determined as well. We concluded that two distinct types of ornithine decarboxylation systems exist in LAB. One is composed of an ornithine decarboxylase coupled to an ornithine/putrescine transmembrane exchanger. Their combined activities results in the extracellular release of putrescine. This typical amino acid decarboxylation system is present in only a few LAB strains and may contribute to metabolic energy production and/or pH homeostasis. The second system is widespread among LAB. It is composed of a decarboxylase active on ornithine and l-2,4-diaminobutyric acid (DABA) and a transporter that mediates unidirectional transport of ornithine into the cytoplasm. Diamines that result from this second system are retained within the cytosol. PMID:22247134

  18. Oxalic acid: a signal molecule for fungus-feeding bacteria of the genus Collimonas?

    PubMed

    Rudnick, M B; van Veen, J A; de Boer, W

    2015-10-01

    Mycophagous (=fungus feeding) soil bacteria of the genus Collimonas have been shown to colonize and grow on hyphae of different fungal hosts as the only source of energy and carbon. The ability to exploit fungal nutrient resources might require a strategy for collimonads to sense fungi in the soil matrix. Oxalic acid is ubiquitously secreted by soil fungi, serving different purposes. In this study, we investigated the possibility that collimonads might use oxalic acid secretion to localize a fungal host and move towards it. We first confirmed earlier indications that collimonads have a very limited ability to use oxalic acid as growth substrate. In a second step, with using different assays, we show that oxalic acid triggers bacterial movement in such a way that accumulation of cells can be expected at micro-sites with high free oxalic acid concentrations. Based on these observations we propose that oxalic acid functions as a signal molecule to guide collimonads to hyphal tips, the mycelial zones that are most sensitive for mycophagous bacterial attack. PMID:25858310

  19. Biofilm-forming bacteria with varying tolerance to peracetic acid from a paper machine.

    PubMed

    Rasimus, Stiina; Kolari, Marko; Rita, Hannu; Hoornstra, Douwe; Salkinoja-Salonen, Mirja

    2011-09-01

    Biofilms cause runnability problems in paper machines and are therefore controlled with biocides. Peracetic acid is usually effective in preventing bulky biofilms. This study investigated the microbiological status of a paper machine where low concentrations (≤ 15 ppm active ingredient) of peracetic acid had been used for several years. The paper machine contained a low amount of biofilms. Biofilm-forming bacteria from this environment were isolated and characterized by 16S rRNA gene sequencing, whole-cell fatty acid analysis, biochemical tests, and DNA fingerprinting. Seventy-five percent of the isolates were identified as members of the subclades Sphingomonas trueperi and S. aquatilis, and the others as species of the genera Burkholderia (B. cepacia complex), Methylobacterium, and Rhizobium. Although the isolation media were suitable for the common paper machine biofoulers Deinococcus, Meiothermus, and Pseudoxanthomonas, none of these were found, indicating that peracetic acid had prevented their growth. Spontaneous, irreversible loss of the ability to form biofilm was observed during subculturing of certain isolates of the subclade S. trueperi. The Sphingomonas isolates formed monoculture biofilms that tolerated peracetic acid at concentrations (10 ppm active ingredient) used for antifouling in paper machines. High pH and low conductivity of the process waters favored the peracetic acid tolerance of Sphingomonas sp. biofilms. This appears to be the first report on sphingomonads as biofilm formers in warm water using industries. PMID:21161323

  20. Submerged yeast fermentation of acid cheese whey for protein production and pollution potential reduction.

    PubMed

    Ghaly, A E; Kamal, M A

    2004-02-01

    Bench-scale batch bioreactors were used to study the effectiveness of cheese whey fermentation for single-cell protein production using the yeast Kluyveromyces fragilis in reducing the pollution potential of whey as measured by solids, chemical oxygen demand (COD) and nitrogenous compounds concentrations. The four principal phases (lag, exponential, stationary and death) encountered in the history of a microbial culture grown under batch conditions were clearly recognized in the growth, temperature and dissolved oxygen curves. The lactose concentration and soluble COD displayed three distinct phases corresponding to the lag, exponential and stationary phases of the yeast growth. The minimum dissolved oxygen and maximum temperature observed in this study (at an air flow of 3 VVM, a mixing speed of 400 rpm and an ambient temperature) were 2.49 mg/L and 31.6 degrees C, respectively. About 99% of lactose (90.6% of soluble COD) was utilized after 28 h. The total COD continued to decline due to cell death resulting in a reduction of 42.98%. The total nitrogen concentration remained unchanged while the organic nitrogen increased during the exponential phase and then declined during the death phase. The ash content remained unchanged while a substantial reduction (56%) of the volatile solids was observed. These results indicated that sufficient oxygen for yeast growth was present in the medium and no cooling system was needed for this type of fermenter under similar experimental conditions. Recovering the yeast biomass with ultrafiltration reduced the total COD by 98% of its initial value in the raw whey. PMID:14723932

  1. Lactic acid bacteria activating innate immunity improve survival in bacterial infection model of silkworm.

    PubMed

    Nishida, Satoshi; Ono, Yasuo; Sekimizu, Kazuhisa

    2016-02-01

    Lactic acid bacteria (LAB) have been thought to be helpful for human heath in the gut as probiotics. It recently was noted that activity of LAB stimulating immune systems is important. Innate immune systems are conserved in mammals and insects. Silkworm has innate immunity in response to microbes. Microbe-associated molecular pattern (ex. peptidoglycan and β-glucan) induces a muscle contraction of silkworm larva. In this study, we established an efficient method to isolate lactic acid bacteria derived from natural products. We selected a highly active LAB to activate the innate immunity in silkworm by using the silkworm muscle contraction assay, as well. The assay revealed that Lactococcus lactis 11/19-B1 was highly active on the stimulation of the innate immunity in silkworm. L. lactis 11/19-B1 solely fermented milk with casamino acid and glucose. This strain would be a starter strain to make yogurt. Compared to commercially available yogurt LAB, L. lactis 11/19-B1 has higher activity on silkworm contraction. Silkworm normally ingested an artificial diet mixed with L. lactis 11/19-B1 or a yogurt fermented with L. lactis 11/19-B1. Interestingly, silkworms that ingested the LAB showed tolerance against the pathogenicity of Pseudomonas aeruginosa. These data suggest that Lactococcus lactis 11/19-B1 would be expected to be useful for making yogurt and probiotics to activate innate immunity. PMID:26971556

  2. Screening and characterization of ethanol-tolerant and thermotolerant acetic acid bacteria from Chinese vinegar Pei.

    PubMed

    Chen, Yang; Bai, Ye; Li, Dongsheng; Wang, Chao; Xu, Ning; Hu, Yong

    2016-01-01

    Acetic acid bacteria (AAB) are important microorganisms in the vinegar industry. However, AAB have to tolerate the presence of ethanol and high temperatures, especially in submerged fermentation (SF), which inhibits AAB growth and acid yield. In this study, seven AAB that are tolerant to temperatures above 40 °C and ethanol concentrations above 10% (v/v) were isolated from Chinese vinegar Pei. All the isolated AAB belong to Acetobacter pasteurianus according to 16S rDNA analysis. Among all AAB, AAB4 produced the highest acid yield under high temperature and ethanol test conditions. At 4% ethanol and 30-40 °C temperatures, AAB4 maintained an alcohol-acid transform ratio of more than 90.5 %. High alcohol-acid transform ratio was still maintained even at higher temperatures, namely, 87.2, 77.1, 14.5 and 2.9% at 41, 42, 43 and 44 °C, respectively. At 30 °C and different initial ethanol concentrations (4-10%), the acid yield by AAB4 increased gradually, although the alcohol-acid transform ratio decreased to some extent. However, 46.5, 8.7 and 0.9% ratios were retained at ethanol concentrations of 11, 12 and 13%, respectively. When compared with AS1.41 (an AAB widely used in China) using a 10 L fermentor, AAB4 produced 42.0 g/L acetic acid at 37 °C with 10% ethanol, whereas AS1.41 almost stopped producing acetic acid. In conclusion, these traits suggest that AAB4 is a valuable strain for vinegar production in SF. PMID:26712629

  3. Use of sourdough made with quinoa (Chenopodium quinoa) flour and autochthonous selected lactic acid bacteria for enhancing the nutritional, textural and sensory features of white bread.

    PubMed

    Rizzello, Carlo Giuseppe; Lorusso, Anna; Montemurro, Marco; Gobbetti, Marco

    2016-06-01

    Lactic acid bacteria were isolated and identified from quinoa flour, spontaneously fermented quinoa dough, and type I quinoa sourdough. Strains were further selected based on acidification and proteolytic activities. Selected Lactobacillus plantarum T6B10 and Lactobacillus rossiae T0A16 were used as mixed starter to get quinoa sourdough. Compared to non-fermented flour, organic acids, free amino acids, soluble fibers, total phenols, phytase and antioxidant activities, and in vitro protein digestibility markedly increased during fermentation. A wheat bread was made using 20% (w/w) of quinoa sourdough, and compared to baker's yeast wheat breads manufactured with or without quinoa flour. The use of quinoa sourdough improved the chemical, textural, and sensory features of wheat bread, showing better performances compared to the use of quinoa flour. Protein digestibility and quality, and the rate of starch hydrolysis were also nutritional features that markedly improved using quinoa sourdough as an ingredient. This study exploited the potential of quinoa flour through sourdough fermentation. A number of advantages encouraged the manufacture of novel and healthy leavened baked goods. PMID:26919812

  4. Iso-branched 2- and 3-hydroxy fatty acids as characteristic lipid constituents of some gliding bacteria.

    PubMed Central

    Fautz, E; Rosenfelder, G; Grotjahn, L

    1979-01-01

    The fatty acids present in the total hydrolysates of several gliding bacteria (Myxococcus fulvus, Stigmatella aurantiaca, Cytophaga johnsonae, Cytophaga sp. strain samoa and Flexibacter elegans) were analyzed by combined gas-liquid chromatography and mass spectrometry. In addition to 13-methyl-tetradecanoic acid, 15-methyl-hexadecanoic acid, hexadecanoic acid, and hexadecenoic acid, 2- and 3-hydroxy fatty acids comprised up to 50% of the total fatty acids. The majority was odd-numbered and iso-branched. Small amounts of even-numbered and unbranched fatty acids were also present. Whereas 2-hydroxy-15-methyl hexadecanoic acid was characteristic for myxobacteria, 2-hydroxy-13-methyl-tetradecanoic acid, 3-hydroxy-13-methyl-tetradecanoic acid, and 3-hydroxy-15-methyl-hexadecanoic acid were dominant in the Cytophaga-Flexibacter group. PMID:118159

  5. Enrichment of conjugated linoleic acid (CLA) in hen eggs and broiler chickens meat by lactic acid bacteria.

    PubMed

    Herzallah, Saqer

    2013-01-01

    1. The aim of this work was to compare conjugated linoleic acid (CLA) concentrations in chickens supplemented with 4 American Tissue Culture Collection (ATCC) bacterial strains, Lactobacillus plantarum, Lactobacillus lactis, Lactobacillus casei and Lactobacillus fermentum, and 4 isolates of Lactobacillus reuteri from camel, cattle, sheep and goat rumen extracts. 2. Micro-organisms were grown anaerobically in MRS broth, and 10(6) CFU/ml of bacteria were administered orally to mixed-sex, 1-d-old broiler chickens weekly for 4 weeks and to 23-week-old layer hens weekly for 6 weeks. 3. The 4 strains were evaluated for their effects on synthesis of CLA in hen eggs and broiler meat cuts. 4. Administration of pure Lactobacillus and isolated L. reuteri strains from camel, cattle, goat and sheep led to significantly increased CLA concentrations of 0.2-1.2 mg/g of fat in eggs and 0.3-1.88 mg/g of fat in broiler chicken flesh homogenates of leg, thigh and breast. 5. These data demonstrate that lactic acid bacteria of animal origin (L. reuteri) significantly enhanced CLA synthesis in both eggs and broiler meat cuts. PMID:24397511

  6. Biodiversity and γ-aminobutyric acid production by lactic acid bacteria isolated from traditional alpine raw cow's milk cheeses.

    PubMed

    Franciosi, Elena; Carafa, Ilaria; Nardin, Tiziana; Schiavon, Silvia; Poznanski, Elisa; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M

    2015-01-01

    "Nostrano-cheeses" are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of "Nostrano-cheeses" and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus. PMID:25802859

  7. Biodiversity and γ-Aminobutyric Acid Production by Lactic Acid Bacteria Isolated from Traditional Alpine Raw Cow's Milk Cheeses

    PubMed Central

    Nardin, Tiziana; Schiavon, Silvia; Cavazza, Agostino; Larcher, Roberto; Tuohy, Kieran M.

    2015-01-01

    “Nostrano-cheeses” are traditional alpine cheeses made from raw cow's milk in Trentino-Alto Adige, Italy. This study identified lactic acid bacteria (LAB) developing during maturation of “Nostrano-cheeses” and evaluated their potential to produce γ-aminobutyric acid (GABA), an immunologically active compound and neurotransmitter. Cheese samples were collected on six cheese-making days, in three dairy factories located in different areas of Trentino and at different stages of cheese ripening (24 h, 15 days, and 1, 2, 3, 6, and 8 months). A total of 1,059 LAB isolates were screened using Random Amplified Polymorphic DNA-PCR (RAPD-PCR) and differentiated into 583 clusters. LAB strains from dominant clusters (n = 97) were genetically identified to species level by partial 16S rRNA gene sequencing. LAB species most frequently isolated were Lactobacillus paracasei, Streptococcus thermophilus, and Leuconostoc mesenteroides. The 97 dominant clusters were also characterized for their ability in producing GABA by high-performance liquid chromatography (HPLC). About 71% of the dominant bacteria clusters evolving during cheeses ripening were able to produce GABA. Most GABA producers were Lactobacillus paracasei but other GABA producing species included Lactococcus lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Pediococcus pentosaceus, and Streptococcus thermophilus. No Enterococcus faecalis or Sc. macedonicus isolates produced GABA. The isolate producing the highest amount of GABA (80.0±2.7 mg/kg) was a Sc. thermophilus. PMID:25802859

  8. The potential of lactic acid bacteria for the production of safe and wholesome food.

    PubMed

    Hammes, W P; Tichaczek, P S

    1994-03-01

    By tradition lactic acid bacteria (LAB) are involved in the production of fermented foods. These constitute one quarter of our diet and are characterized by a safe history, certain beneficial health effects, and an extended shelf life when compared with raw materials. The various fermenting substrates are habitats for specific LAB that differ in their metabolic potential. The health effects exerted by LAB are the following: 1. Production of lactic acid and minor amounts of acetic and formic acid. These cause: a drop in pH and thereby growth inhibition of food spoiling or poisoning bacteria; killing of certain pathogens; detoxification by degradation of noxious compounds of plant origin (usually in combination with plant-derived enzymatic activities). 2. Production of antimicrobial compounds (e.g. bacteriocins, H2O2, fatty acids). 3. Probiotic effects as live organisms in food. The wholesomeness of LAB can also be extended to fields outside human nutrition, as they may act as probiotics in animal production or as plant protectives in agriculture and thus contribute to healthy raw materials for food production. Modern concepts or perspectives of the application of LAB include the following: 1. Selection of the best adapted and safely performing LAB strains. 2. Selection of strains with probiotic effects. 3. Selection of strains with health-promoting effects (e.g. production of vitamins or essential amino acids, anti-tumour activity). 4. Selection of strains with food protective activities (inhibiting spoilage or food pathogens). These strains can be added to food or used as starters in food fermentations. They may be found as wild-type organisms or can be obtained by genetic engineering.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8178575

  9. Metabolic engineering of lactic acid bacteria for the production of industrially important compounds

    PubMed Central

    Papagianni, Maria

    2012-01-01

    Lactic acid bacteria (LAB) are receiving increased attention for use as cell factories for the production of metabolites with wide use by the food and pharmaceutical industries. The availability of efficient tools for genetic modification of LAB during the past decade permitted the application of metabolic engineering strategies at the levels of both the primary and the more complex secondary metabolism. The recent developments in the area with a focus on the production of industrially important metabolites will be discussed in this review. PMID:24688663

  10. Stable carbon isotope analysis of nucleic acids to trace sources of dissolved substrates used by estuarine bacteria.

    PubMed Central

    Coffin, R B; Velinsky, D J; Devereux, R; Price, W A; Cifuentes, L A

    1990-01-01

    The natural abundance of stable carbon isotopes measured in bacterial nucleic acids extracted from estuarine bacterial concentrates was used to trace sources of organic matter for bacteria in aquatic environments. The stable carbon isotope ratios of Pseudomonas aeruginosa and nucleic acids extracted from cultures resembled those of the carbon source on which bacteria were grown. The carbon isotope discrimination between the substrate and total cell carbon from bacterial cultures averaged 2.3% +/- 0.6% (n = 13). Furthermore, the isotope discrimination between the substrate and nucleic acids extracted from bacterial cultures was 2.4% +/- 0.4% (n = 10), not significantly different from the discrimination between bacteria and the substrate. Estuarine water samples were prefiltered through 1-micron-pore-size cartridge filters. Bacterium-sized particles in the filtrates were concentrated with tangential-flow filtration and centrifugation, and nucleic acids were then extracted from these concentrates. Hybridization with 16S rRNA probes showed that approximately 90% of the nucleic acids extracted on two sample dates were of eubacterial origin. Bacteria and nucleic acids from incubation experiments using estuarine water samples enriched with dissolved organic matter from Spartina alterniflora and Cyclotella caspia had stable carbon isotope values similar to those of the substrate sources. In a survey that compared diverse estuarine environments, stable carbon isotopes of bacteria grown in incubation experiments ranged from -31.9 to -20.5%. The range in isotope values of nucleic acids extracted from indigenous bacteria from the same waters was similar, -27.9 to -20.2%. Generally, the lack of isotope discrimination between bacteria and nucleic acids that was noted in the laboratory was observed in the field.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2389930

  11. Phage-Host Interactions of Cheese-Making Lactic Acid Bacteria.

    PubMed

    Mahony, Jennifer; McDonnell, Brian; Casey, Eoghan; van Sinderen, Douwe

    2016-01-01

    Cheese production is a global biotechnological practice that is reliant on robust and technologically appropriate starter and adjunct starter cultures to acidify the milk and impart particular flavor and textural properties to specific cheeses. To this end, lactic acid bacteria, including Lactococcus lactis, Streptococcus thermophilus, and Lactobacillus and Leuconostoc spp., are routinely employed. However, these bacteria are susceptible to infection by (bacterio)phages. Over the past decade in particular, significant advances have been achieved in defining the receptor molecules presented by lactococcal host bacteria and in the structural analysis of corresponding phage-encoded receptor-binding proteins. These lactococcal model systems are expanding toward understanding phage-host interactions of other LAB species. Ultimately, such scientific efforts will uncover the mechanistic (dis)similarities among these phages and define how these phages recognize and infect their hosts. This review presents the current status of the LAB-phage interactome, highlighting the most recent and significant developments in this active research field. PMID:26735798

  12. Application of lactic acid bacteria in removing heavy metals and aflatoxin B1 from contaminated water.

    PubMed

    Elsanhoty, Rafaat M; Al-Turki, I A; Ramadan, Mohamed Fawzy

    2016-01-01

    In this study selected lactic acid bacteria (LAB, Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus plantrium and Streptococcus thermophiles) and probiotic bacteria (Bifidobacterium angulatum) were tested for their ability in removing heavy metals (HM) including cadmium (Cd), lead (Pb) and arsenic (As) as well as aflatoxin B1 (AFB1) from contaminated water. The biosorption parameters (pH, bacterial concentration, contact time and temperature) of removal using individual as well as mixed LAB and probiotic bacteria were studied. Removal of HM and AFB1 depended on the strain, wherein the process was strongly pH-dependent with high removal ability at a pH close to neutral. The increase in bacterial concentration enhanced the removal of Cd, Pb and As. Also, increasing of contact time and temperature increased the ability of LAB to remove HM. The effect of contact time on Cd removal was slightly different when freshly cultured cells were used. The removal of Cd, Pb and As decreased with the increase in the initial metal concentration. The most effective HM removers were Lactobacillus acidophilus and Bifidobacterium angulatum. The system was found to be adequate for concentrations of HM under investigation. At the end of the operation, the concentration of HM reached the level allowed by the World Health Organization regulations. PMID:27508367

  13. Uric Acid-Degrading Bacteria in Guts of Termites [Reticulitermes flavipes (Kollar)] †

    PubMed Central

    Potrikus, C. J.; Breznak, John A.

    1980-01-01

    Uricolytic bacteria were present in guts of Reticulitermes flavipes in populations up to 6 × 104 cells per gut. Of 82 strains isolated under strict anaerobic conditions, most were group N Streptococcus sp., Bacteroides termitidis, and Citrobacter sp. All isolates used uric acid (UA) as an energy source anaerobically, but not aerobically, and NH3 was the major nitrogenous product of uricolysis. However, none of the isolates had an absolute requirement for UA. Utilization of heterocyclic compounds other than UA was limited. Fresh termite gut contents also degraded UA anaerobically, as measured by 14CO2 evolution from [2-14C]UA. The magnitude of anaerobic uricolysis [0.67 pmol of UA catabolized/(gut × h)] was entirely consistent with the population density of uricolytic bacteria in situ. Uricolytic gut bacteria may convert UA in situ to products usable by termites for carbon, nitrogen, energy, or all three. This possibility is consistent with the fact that R. flavipes termites from UA, but they do not void the purine in excreta despite the lack of uricase in their tissues. PMID:16345587

  14. Potential of selected lactic acid bacteria to produce food compatible antifungal metabolites.

    PubMed

    De Muynck, Cassandra; Leroy, Annelies I J; De Maeseneire, Sofie; Arnaut, Filip; Soetaert, Wim; Vandamme, Erick J

    2004-01-01

    The aim of this study was to assess the potential of lactic acid bacteria to inhibit the outgrowth of some common food-spoiling fungi. Culture supernatants of 17 Lactic acid bacterial strains as well as of three commercial probiotic cultures were evaluated for antifungal activity using an agar-diffusion method. The method parameters were chosen in order to reveal compounds for potential use in food (bio)preservation. Thirteen strains showed antifungal activity of which five strains were very promising: Lactobacillus acidophilus LMG 9433, L. amylovorus DSM 20532, L. brevis LMG 6906, L. coryniformis subsp. coryniformis LMG 9196 and L. plantarum LMG 6907. Four of these five strains were further examined; it was found that the produced antifungal metabolites were pH-dependent. The exact chemical nature of these substances has not been revealed yet. PMID:15646380

  15. Root-Secreted Malic Acid Recruits Beneficial Soil Bacteria1[C][W][OA

    PubMed Central

    Rudrappa, Thimmaraju; Czymmek, Kirk J.; Paré, Paul W.; Bais, Harsh P.

    2008-01-01

    Beneficial soil bacteria confer immunity against a wide range of foliar diseases by activating plant defenses, thereby reducing a plant's susceptibility to pathogen attack. Although bacterial signals have been identified that activate these plant defenses, plant metabolites that elicit rhizobacterial responses have not been demonstrated. Here, we provide biochemical evidence that the tricarboxylic acid cycle intermediate l-malic acid (MA) secreted from roots of Arabidopsis (Arabidopsis thaliana) selectively signals and recruits the beneficial rhizobacterium Bacillus subtilis FB17 in a dose-dependent manner. Root secretions of l-MA are induced by the foliar pathogen Pseudomonas syringae pv tomato (Pst DC3000) and elevated levels of l-MA promote binding and biofilm formation of FB17 on Arabidopsis roots. The demonstration that roots selectively secrete l-MA and effectively signal beneficial rhizobacteria establishes a regulatory role of root metabolites in recruitment of beneficial microbes, as well as underscores the breadth and sophistication of plant-microbial interactions. PMID:18820082

  16. Rapid identification of acetic acid bacteria using MALDI-TOF mass spectrometry fingerprinting.

    PubMed

    Andrés-Barrao, Cristina; Benagli, Cinzia; Chappuis, Malou; Ortega Pérez, Ruben; Tonolla, Mauro; Barja, François

    2013-03-01

    Acetic acid bacteria (AAB) are widespread microorganisms characterized by their ability to transform alcohols and sugar-alcohols into their corresponding organic acids. The suitability of matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF MS) for the identification of cultured AAB involved in the industrial production of vinegar was evaluated on 64 reference strains from the genera Acetobacter, Gluconacetobacter and Gluconobacter. Analysis of MS spectra obtained from single colonies of these strains confirmed their basic classification based on comparative 16S rRNA gene sequence analysis. MALDI-TOF analyses of isolates from vinegar cross-checked by comparative sequence analysis of 16S rRNA gene fragments allowed AAB to be identified, and it was possible to differentiate them from mixed cultures and non-AAB. The results showed that MALDI-TOF MS analysis was a rapid and reliable method for the clustering and identification of AAB species. PMID:23182036

  17. Effect of pH alkaline salts of fatty acids on the inhibition of bacteria associated with poultry processing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The agar diffusion assay was used to examine the effect of pH on the ability of alkaline salts of three fatty acids (FA) to inhibit growth of bacteria associated with poultry processing. FA solutions were prepared by dissolving 0.5 M concentrations of caprylic, capric, or lauric acid in separate ali...

  18. Draft Genome Sequences of Gluconobacter cerinus CECT 9110 and Gluconobacter japonicus CECT 8443, Acetic Acid Bacteria Isolated from Grape Must

    PubMed Central

    Sainz, Florencia

    2016-01-01

    We report here the draft genome sequences of Gluconobacter cerinus strain CECT9110 and Gluconobacter japonicus CECT8443, acetic acid bacteria isolated from grape must. Gluconobacter species are well known for their ability to oxidize sugar alcohols into the corresponding acids. Our objective was to select strains to oxidize effectively d-glucose. PMID:27365351

  19. Succinic acid in levels produced by yeast (Saccharomyces cerevisiae) during fermentation strongly impacts wheat bread dough properties.

    PubMed

    Jayaram, Vinay B; Cuyvers, Sven; Verstrepen, Kevin J; Delcour, Jan A; Courtin, Christophe M

    2014-05-15

    Succinic acid (SA) was recently shown to be the major pH determining metabolite produced by yeast during straight-dough fermentation (Jayaram et al., 2013), reaching levels as high as 1.6 mmol/100 g of flour. Here, the impact of such levels of SA (0.8, 1.6 and 2.4 mmol/100 g flour) on yeastless dough properties was investigated. SA decreased the development time and stability of dough significantly. Uniaxial extension tests showed a consistent decrease in dough extensibility upon increasing SA addition. Upon biaxial extension in the presence of 2.4 mmol SA/100 g flour, a dough extensibility decrease of 47-65% and a dough strength increase of 25-40% were seen. While the SA solvent retention capacity of flour increased with increasing SA concentration in the solvent, gluten agglomeration decreased with gluten yield reductions of over 50%. The results suggest that SA leads to swelling and unfolding of gluten proteins, thereby increasing their interaction potential and dough strength, but simultaneously increasing intermolecular electrostatic repulsive forces. These phenomena lead to the reported changes in dough properties. Together, our results establish SA as an important yeast metabolite for dough rheology. PMID:24423552

  20. Candida digboiensis sp. nov., a novel anamorphic yeast species from an acidic tar sludge-contaminated oilfield.

    PubMed

    Prasad, G S; Mayilraj, S; Sood, Nitu; Singh, Vijeyta; Biswas, Kakoli; Lal, Banwari

    2005-03-01

    Two strains (TERI-6(T) and TERI-7) of a novel yeast species were isolated from acidic tar sludge-contaminated soil samples collected from Digboi Refinery, Assam, India. These two yeast strains were morphologically, physiologically and phylogenetically identical to each other. No sexual reproduction was observed on corn meal, malt, Gorodkowa, YM or V8 agars. Physiologically, the novel isolates were most closely related to Candida blankii, but differed in eight physiological tests. The prominent differences were the ability of the isolates to assimilate melibiose and inulin and their inability to assimilate d-glucuronate, succinate and citrate. Phylogenetic analysis using the D1/D2 variable domain showed that the closest relative of these strains is C. blankii (2.8 % divergence). Other related species are Zygoascus hellenicus and Candida bituminiphila. The isolates differed from C. blankii by 11 base substitutions in the 18S rRNA gene sequence and by 58 base substitutions in the internal transcribed spacer sequences. The physiological, biochemical and molecular data support the contention that strains TERI-6(T) and TERI-7 represent a novel species, for which the name Candida digboiensis sp. nov. is proposed. The type strain is TERI-6(T) (=MTCC 4371(T)=CBS 9800(T)=JCM 12300(T)). PMID:15774693

  1. Isolation of Lactic Acid Bacteria Showing Antioxidative and Probiotic Activities from Kimchi and Infant Feces.

    PubMed

    Ji, Keunho; Jang, Na Young; Kim, Young Tae

    2015-09-01

    The purpose of this study was to investigate lactic acid bacteria with antioxidative and probiotic activities isolated from Korean healthy infant feces and kimchi. Isolates A1, A2, S1, S2, and S3 were assigned to Lactobacillus sp. and isolates A3, A4, E1, E2, E3, and E4 were assigned to Leuconostoc sp. on the basis of their physiological properties and 16S ribosomal DNA sequence analysis. Most strains were confirmed as safe bioresources through nonhemolytic activities and non-production of harmful enzymes such as β-glucosidase, β- glucuronidase and tryptophanase. The 11 isolates showed different resistance to acid and bile acids. In addition, they exhibited antibacterial activity against foodborne bacteria, especially Bacillus cereus, Listeria monocytogenes, and Escherichia coli. Furthermore, all strains showed significantly high levels of hydrophobicity. The antioxidant effects of culture filtrates of the 11 strains included 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity, 2.2'- azino-bis (2-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation scavenging activity, and superoxide dismutase activity. The results revealed that most of the culture filtrates have effective scavenging activity for DPPH and ABTS radicals. All strains appeared to have effective superoxide dismutase activity. In conclusion, the isolated strains A1, A3, S1, and S3 have significant probiotic activities applicable to the development of functional foods and health-related products. These strains might also contribute to preventing and controlling several diseases associated with oxidative stress, when used as probiotics. PMID:25951843

  2. Sourdough lactic acid bacteria: exploration of non-wheat cereal-based fermentation.

    PubMed

    Coda, Rossana; Cagno, Raffaella Di; Gobbetti, Marco; Rizzello, Carlo Giuseppe

    2014-02-01

    Cereal-based foods represent a very important source of biological as well as of cultural diversity, as testified by the wide range of derived fermented products. A trend that is increasingly attracting bakery industries as well as consumers is the use of non-conventional flours for the production of novel products, characterised by peculiar flavour and better nutritional value. Lactic acid bacteria microbiota of several non-wheat cereals and pseudo-cereals has been recently deeply investigated with the aim of studying the biodiversity and finding starter cultures for sourdough fermentation. Currently, the use of ancient or ethnic grains is mainly limited to traditional typical foods and the bread making process is not well standardised with consequent negative effects on the final properties. The challenge in fermenting such grains is represented by the necessity to combine good technology and sensory properties with nutritional/health benefits. The choice of the starter cultures has a critical impact on the final quality of cereal-based products, and strains that dominate and outcompete contaminants should be applied for specific sourdough fermentations. In this sense, screening and characterisation of the lactic acid bacteria microbiota is very useful in the improvement of a peculiar flour, from both a nutritional and technological point of view. PMID:24230473

  3. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions. PMID:25228086

  4. Molecular diversity of lactic acid bacteria from cassava sour starch (Colombia).

    PubMed

    Omar, N B; Ampe, F; Raimbault, M; Guyot, J P; Tailliez, P

    2000-06-01

    Lactic acid bacteria and more particularly lactobacilli and Leuconostoc, are widely found in a wide variety of traditional fermented foods of tropical countries, made with cereals, tubers, meat or fish. These products represent a source of bacterial diversity that cannot be accurately analysed using classical phenotypic and biochemical tests. In the present work, the identification and the molecular diversity of lactic acid bacteria isolated from cassava sour starch fermentation were assessed by using a combination of complementary molecular methods: Randomly Amplified Polymorphic DNA fingerprinting (RAPD), plasmid profiling, hybridization using rRNA phylogenetic probes and partial 16S rDNA sequencing. The results revealed a large diversity of bacterial species (Lb. manihotivorans, Lb. plantarum, Lb. casei, Lb. hilgardii, Lb. buchneri, Lb. fermentum, Ln. mesenteroides and Pediococcus sp.). However, the most frequently isolated species were Lb. plantarum and Lb. manihotivorans. The RAPD analysis revealed a large molecular diversity between Lb. manihotivorans or Lb. plantarum strains. These results, observed on a rather limited number of samples, reveal that significant bacterial diversity is generated in traditional cassava sour starch fermentations. We propose that the presence of the amylolytic Lb. manihotivorans strains could have a role in sour starch processing. PMID:10930082

  5. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    PubMed

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. PMID:27058913

  6. ADANSONIAN ANALYSIS AND DEOXYRIBONUCLEIC ACID BASE COMPOSITION OF SOME GRAM-NEGATIVE BACTERIA

    PubMed Central

    Colwell, R. R.; Mandel, M.

    1964-01-01

    Colwell, R. R. (Georgetown University, Washington, D.C.), and M. Mandel. Adansonian analysis and deoxyribonucleic acid base composition of some gram-negative bacteria. J. Bacteriol. 87:1412–1422. 1964.—The deoxyribonucleic acid (DNA) base compositions and S values for a minimum of 134 coded properties were determined for representative cultures of the genera Pseudomonas, Xanthomonas, Aeromonas, Vibrio, Aerobacter, Escherichia, Alcaligenes, and Flavobacterium. Those cultures having a high degree of similarity by the criterion of numerical taxonomy were found to have similar DNA base compositions. The relative affinities of clusters of cultures suggest taxonomic relations. Eleven species of Xanthomonas might be a single species, and V. metschnikovii was shown to be more closely related to enteric bacteria than to other vibrios which, in turn, were found to be like pseudomonads. Aeromonas was found to be intermediate in similarity to enterics and pseudomonads and divisible into at least two, but possibly three, species. F. aquatile was unlike any of the other organisms studied, and its DNA also differed greatly in composition from other representatives of the genus. PMID:14188722

  7. Chemotactic behavior of deep subsurface bacteria toward carbohydrates, amino acids and a chlorinated alkene

    SciTech Connect

    Lopez de Victoria, G. . Dept. of Biology)

    1989-02-01

    The chemotactic behavior of deep terrestrial subsurface bacteria toward amino acids, carbohydrates and trichloroethylene was assayed using a modification of the capillary method and bacterial enumeration by acridine orange direct counts. Eleven isolates of bacteria isolated from six different geological formations were investigated. A bimodal response rather than an absolute positive or negative response was observed in most assays. Most of the isolates were positively chemotactic to low concentrations of substrates and were repelled by high concentrations of the same substrate. However, this was not the case for trichloroethylene (TCE) which was mostly an attractant and elicited the highest responses in all the isolates when compared with amino acids and carbohydrates. The movement rates of these isolates in aseptic subsurface sediments in the absence and presence of TCE were also determined using a laboratory model. All of the isolates showed distinct response range, peak, and threshold concentrations when exposed to the same substrates suggesting that they are possibly different species as has been inferred from DNA homology studies. 101 refs., 4 figs., 57 tabs.

  8. Lactic acid bacteria producing B-group vitamins: a great potential for functional cereals products.

    PubMed

    Capozzi, Vittorio; Russo, Pasquale; Dueñas, María Teresa; López, Paloma; Spano, Giuseppe

    2012-12-01

    Wheat contains various essential nutrients including the B group of vitamins. However, B group vitamins, normally present in cereals-derived products, are easily removed or destroyed during milling, food processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of a large variety of foods and can improve the safety, shelf life, nutritional value, flavor and overall quality of the fermented products. In this regard, the identification and application of strains delivering health-promoting compounds is a fascinating field. Besides their key role in food fermentations, several LAB found in the gastrointestinal tract of humans and animals are commercially used as probiotics and possess generally recognized as safe status. LAB are usually auxotrophic for several vitamins although certain strains of LAB have the capability to synthesize water-soluble vitamins such as those included in the B group. In recent years, a number of biotechnological processes have been explored to perform a more economical and sustainable vitamin production than that obtained via chemical synthesis. This review article will briefly report the current knowledge on lactic acid bacteria synthesis of vitamins B2, B11 and B12 and the potential strategies to increase B-group vitamin content in cereals-based products, where vitamins-producing LAB have been leading to the elaboration of novel fermented functional foods. In addition, the use of genetic strategies to increase vitamin production or to create novel vitamin-producing strains will be also discussed. PMID:23093174

  9. Honeybees and beehives are rich sources for fructophilic lactic acid bacteria.

    PubMed

    Endo, Akihito; Salminen, Seppo

    2013-09-01

    Fructophilic lactic acid bacteria (FLAB) are a specific group of lactic acid bacteria (LAB) characterized and described only recently. They prefer fructose as growth substrate and inhabit only fructose-rich niches. Honeybees are high-fructose-consuming insects and important pollinators in nature, but reported to be decreasing in the wild. In the present study, we analyzed FLAB microbiota in honeybees, larvae, fresh honey and bee pollen. A total of 66 strains of LAB were isolated from samples using a selective isolation technique for FLAB. Surprisingly, all strains showed fructophilic characteristics. The 66 strains and ten FLAB strains isolated from flowers in a separate study were genotypically separated into six groups, four of which being identified as Lactobacillus kunkeei and two as Fructobacillus fructosus. One of the L. kunkeei isolates showed antibacterial activity against Melissococcus plutonius, a causative pathogen of European foulbrood, this protection being attributable to production of an antibacterial peptide or protein. Culture-independent analysis suggested that bee products and larvae contained simple Lactobacillus-group microbiota, dominated by L. kunkeei, although adult bees carried a more complex microbiota. The findings clearly demonstrate that honeybees and their products are rich sources of FLAB, and FLAB are potential candidates for future bee probiotics. PMID:23845309

  10. Sugar-coated: exopolysaccharide producing lactic acid bacteria for food and human health applications.

    PubMed

    Ryan, P M; Ross, R P; Fitzgerald, G F; Caplice, N M; Stanton, C

    2015-03-01

    The human enteric microbiome represents a veritable organ relied upon by the host for a range of metabolic and homeostatic functions. Through the production of metabolites such as short chain fatty acids (SCFA), folate, vitamins B and K, lactic acid, bacteriocins, peroxides and exopolysaccharides, the bacteria of the gut microbiome provide nutritional components for colonocytes, liver and muscle cells, competitively exclude potential pathogenic organisms and modulate the hosts immune system. Due to the extensive variation in structure, size and composition, microbial exopolysaccharides represent a useful set of versatile natural ingredients for the food industrial sector, both in terms of their rheological properties and in many cases, their associated health benefits. The exopolysaccharide-producing bacteria that fall within the 35 Lactobacillus and five Bifidobacterium species which have achieved qualified presumption of safety (QPS) and generally recognised as safe (GRAS) status are of particular interest, as their inclusion in food products can avoid considerable scrutiny. In addition, additives commonly utilised by the food industry are becoming unattractive to the consumer, due to the demand for a more 'natural' and 'clean labelled' diet. In situ production of exopolysaccharides by food-grade cultures in many cases confers similar rheological and sensory properties in fermented dairy products, as traditional additives, such as hydrocolloids, collagen and alginate. This review will focus on microbial synthesis of exopolysaccharides, the human health benefits of dietary exopolysaccharides and the technofunctional applications of exopolysaccharide-synthesising microbes in the food industry. PMID:25580594

  11. Selective removal of transition metals from acidic mine waters by novel consortia of acidophilic sulfidogenic bacteria

    PubMed Central

    Ňancucheo, Ivan; Johnson, D. Barrie

    2012-01-01

    Summary Two continuous‐flow bench‐scale bioreactor systems populated by mixed communities of acidophilic sulfate‐reducing bacteria were constructed and tested for their abilities to promote the selective precipitation of transition metals (as sulfides) present in synthetic mine waters, using glycerol as electron donor. The objective with the first system (selective precipitation of copper from acidic mine water containing a variety of soluble metals) was achieved by maintaining a bioreactor pH of ∼2.2–2.5. The second system was fed with acidic (pH 2.5) synthetic mine water containing 3 mM of both zinc and ferrous iron, and varying concentrations (0.5–30 mM) of aluminium. Selective precipitation of zinc sulfide was possible by operating the bioreactor at pH 4.0 and supplementing the synthetic mine water with 4 mM glycerol. Analysis of the microbial populations in the bioreactors showed that they changed with varying operational parameters, and novel acidophilic bacteria (including one sulfidogen) were isolated from the bioreactors. The acidophilic sulfidogenic bioreactors provided ‘proof of principle’ that segregation of metals present in mine waters is possible using simple online systems within which controlled pH conditions are maintained. The modular units are versatile and robust, and involve minimum engineering complexity. PMID:21895996

  12. Modelling and predicting the simultaneous growth of Escherichia coli and lactic acid bacteria in milk.

    PubMed

    Ačai, P; Valík, L'; Medved'ová, A; Rosskopf, F

    2016-09-01

    Modelling and predicting the simultaneous competitive growth of Escherichia coli and starter culture of lactic acid bacteria (Fresco 1010, Chr. Hansen, Hørsholm, Denmark) was studied in milk at different temperatures and Fresco inoculum concentrations. The lactic acid bacteria (LAB) were able to induce an early stationary state in E. coli The developed model described and tested the growth inhibition of E. coli (with initial inoculum concentration 10(3) CFU/mL) when LAB have reached maximum density in different conditions of temperature (ranging from 12 ℃ to 30 ℃) and for various inoculum sizes of LAB (ranging from approximately 10(3) to 10(7) CFU/mL). The prediction ability of the microbial competition model (the Baranyi and Roberts model coupled with the Gimenez and Dalgaard model) was first performed only with parameters estimated from individual growth of E. coli and the LAB and then with the introduced competition coefficients evaluated from co-culture growth of E. coli and LAB in milk. Both the results and their statistical indices showed that the model with incorporated average values of competition coefficients improved the prediction of E. coli behaviour in co-culture with LAB. PMID:26683482

  13. Prediction of acid lactic-bacteria growth in turkey ham processed by high hydrostatic pressure

    PubMed Central

    Mathias, S.P.; Rosenthal, A.; Gaspar, A.; Aragão, G.M.F.; Slongo-Marcusi, A.

    2013-01-01

    High hydrostatic pressure (HHP) has been investigated and industrially applied to extend shelf life of meat-based products. Traditional ham packaged under microaerophilic conditions may sometimes present high lactic acid bacteria population during refrigerated storage, which limits shelf life due to development of unpleasant odor and greenish and sticky appearance. This study aimed at evaluating the shelf life of turkey ham pressurized at 400 MPa for 15 min and stored at 4, 8 and 12 °C, in comparison to the non pressurized product. The lactic acid bacteria population up to 107 CFU/g of product was set as the criteria to determine the limiting shelf life According to such parameter the pressurized sample achieved a commercial viability within 75 days when stored at 4 °C while the control lasted only 45 days. Predictive microbiology using Gompertz and Baranyi and Roberts models fitted well both for the pressurized and control samples. The results indicated that the high hydrostatic pressure treatment greatly increased the turkey ham commercial viability in comparison to the usual length, by slowing down the growth of microorganisms in the product. PMID:24159279

  14. Screening, Characterization and In Vitro Evaluation of Probiotic Properties Among Lactic Acid Bacteria Through Comparative Analysis.

    PubMed

    Devi, Sundru Manjulata; Archer, Ann Catherine; Halami, Prakash M

    2015-09-01

    The present work aimed to identify probiotic bacteria from healthy human infant faecal and dairy samples. Subsequently, an assay was developed to evaluate the probiotic properties using comparative genetic approach for marker genes involved in adhesion to the intestinal epithelial layer. Several in vitro properties including tolerance to biological barriers (such as acid and bile), antimicrobial spectrum, resistance to simulated digestive fluids and cellular hydrophobicity were assessed. The potential probiotic cultures were rapidly characterized by morphological, physiological and molecular-based methods [such as RFLP, ITS, RAPD and (GTG)5]. Further analysis by 16S rDNA sequencing revealed that the selected isolates belong to Lactobacillus, Pediococcus and Enterococcus species. Two cultures of non-lactic, non-pathogenic Staphylococcus spp. were also isolated. The native isolates were able to survive under acidic, bile and simulated intestinal conditions. In addition, these cultures inhibited the growth of tested bacterial pathogens. Further, no correlation was observed between hydrophobicity and adhesion ability. Sequencing of probiotic marker genes such as bile salt hydrolase (bsh), fibronectin-binding protein (fbp) and mucin-binding protein (mub) for selected isolates revealed nucleotide variation. The probiotic binding domains were detected by several bioinformatic tools. The approach used in the study enabled the identification of potential probiotic domains responsible for adhesion of bacteria to intestinal epithelial layer, which may further assist in screening of novel probiotic bacteria. The rapid detection of binding domains will help in revealing the beneficial properties of the probiotic cultures. Further, studies will be performed to develop a novel probiotic product which will contribute in food and feed industry. PMID:26049925

  15. Isolating and evaluating lactic acid bacteria strains for effectiveness of Leymus chinensis silage fermentation.

    PubMed

    Zhang, Q; Li, X J; Zhao, M M; Yu, Z

    2014-10-01

    Five LAB strains were evaluated using the acid production ability test, morphological observation, Gram staining, physiological, biochemical and acid tolerance tests. All five strains (LP1, LP2, LP3, LC1 and LC2) grew at pH 4·0, and LP1 grew at 15°C. Strains LP1, LP2 and LP3 were identified as Lactobacillus plantarum, whereas LC1 and LC2 were classified as Lactobacillus casei by sequencing 16S rDNA. The five isolated strains and two commercial inoculants (PS and CL) were added to native grass and Leymus chinensis (Trin.) Tzvel. for ensiling. All five isolated strains decreased the pH and ammonia nitrogen content, increased the lactic acid content and LP1, LP2 and LP3 increased the acetic content and lactic/acetic acid ratio of L. chinensis silage significantly. The five isolated strains and two commercial inoculants decreased the butyric acid content of the native grass silage. LP2 treatment had lower butyric acid content and ammonia nitrogen content than the other treatments. The five isolated strains improved the quality of L. chinensis silage. The five isolated strains and the two commercial inoculants were not effective in improving the fermentation quality of the native grass silage, but LP2 performed better comparatively. Significance and impact of the study: Leymus chinensis is an important grass in China and Russia, being the primary grass of the short grassland 'steppe' regions of central Asia. However, it has been difficult to make high-quality silage of this species because of low concentration of water-soluble carbohydrates (WSC). Isolating and evaluating lactic acid bacteria strains will be helpful for improving the silage quality of this extensively grown species. PMID:24888497

  16. [Directed isolation of gram-negative asporogenous bacteria from natural substrates].

    PubMed

    Ivanitskaia, L P; Singal, E M; Bodunkova, L E; Ostanina, L N; Baturina, M V

    1984-10-01

    A method for selective isolation of gramnegative nonsporulating bacteria from soil substrates was developed. The method consists of plating out the substrates on a glucose-yeast medium with addition of benzylpenicillin and nalidixic acid. The isolation frequency of gramnegative nonsporulating bacteria increased under such conditions from 9-16 (control) to 80-100 per cent. At the same time the isolation frequency of gram-positive bacteria decreased from 88.5 to 9.6 per cent. PMID:6391365

  17. Extraction of ethanol with higher carboxylic acid solvents and their toxicity to yeast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In a screening exercise for ethanol-selective extraction solvents, partitioning of ethanol and water from a 5 wt% aqueous solution into several C8 – C18 carboxylic acids was studied. Results for the acids are compared with those from alcohols of similar structure. In all cases studied, the acids exh...

  18. A prebiotic role of Ecklonia cava improves the mortality of Edwardsiella tarda-infected zebrafish models via regulating the growth of lactic acid bacteria and pathogen bacteria.

    PubMed

    Lee, WonWoo; Oh, Jae Young; Kim, Eun-A; Kang, Nalae; Kim, Kil-Nam; Ahn, Ginnae; Jeon, You-Jin

    2016-07-01

    In this study, the beneficial prebiotic roles of Ecklonia cava (E. cava, EC) were evaluated on the growth of lactic acid bacteria (LAB) and pathogen bacteria and the mortality of pathogen-bacteria infected zebrafish model. The result showed that the original E. cava (EC) led to the highest growth effects on three LABs (Lactobacillus brevis, L. brevis; Lactobacillus pentosus, L. pentosus; Lactobacillus plantarum; L. plantarum) and it was dose-dependent manners. Also, EC, its Celluclast enzymatic (ECC) and 100% ethanol extracts (ECE) showed the anti-bacterial activities on the fish pathogenic bacteria such as (Edwardsiella tarda; E. tarda, Streptococcus iniae; S. iniae, and Vibrio harveyi; V. harveyi). Interestingly, EC induced the higher production of the secondary metabolites from L. plantarum in MRS medium. The secondary metabolites produced by EC significantly inhibited the growth of pathogen bacteria. In further in vivo study, the co-treatment of EC and L. plantarum improved the growth and mortality of E. tarda-infected zebrafish as regulating the expression of inflammatory molecules such as iNOS and COX2. Taken together, our present study suggests that the EC plays an important role as a potential prebiotic and has a protective effect against the infection caused by E. tarda injection in zebrafish. Also, our conclusion from this evidence is that EC can be used and applied as a useful prebiotic. PMID:27192145

  19. Antimicrobial activity of an Amazon medicinal plant (Chancapiedra) (Phyllanthus niruri L.) against Helicobacter pylori and lactic acid bacteria.

    PubMed

    Ranilla, Lena Gálvez; Apostolidis, Emmanouil; Shetty, Kalidas

    2012-06-01

    The potential of water extracts of the Amazon medicinal plant Chancapiedra (Phyllanthus niruri L.) from Ecuador and Peru for antimicrobial activity against Helicobacter pylori and different strains of lactic acid bacteria such as Lactobacillus acidophilus, Lactobacillus casei and Lactobacillus plantarum was investigated. H. pylori was inhibited by both water extracts in a dose dependent manner, whereas lactic acid bacterial growth was not affected. Both extracts contained ellagic acid and hydroxycinnamic acid derivatives and exhibited high free radical scavenging linked-antioxidant activities (89%). However, gallic acid was detected only in the Ecuadorian extract. Preliminary studies on the mode of action of Chancapiedra against H. pylori revealed that inhibition may not involve proline dehydrogenase-based oxidative phosphorylation inhibition associated with simple mono-phenolics and could involve ellagitannins or other non-phenolic compounds through a yet unknown mechanism. This study provides evidence about the potential of Chancapiedra for H. pylori inhibition without affecting beneficial lactic acid bacteria. PMID:22034238

  20. Unified Theory of Bacterial Sialometabolism: How and Why Bacteria Metabolize Host Sialic Acids

    PubMed Central

    Vimr, Eric R.

    2013-01-01

    Sialic acids are structurally diverse nine-carbon ketosugars found mostly in humans and other animals as the terminal units on carbohydrate chains linked to proteins or lipids. The sialic acids function in cell-cell and cell-molecule interactions necessary for organismic development and homeostasis. They not only pose a barrier to microorganisms inhabiting or invading an animal mucosal surface, but also present a source of potential carbon, nitrogen, and cell wall metabolites necessary for bacterial colonization, persistence, growth, and, occasionally, disease. The explosion of microbial genomic sequencing projects reveals remarkable diversity in bacterial sialic acid metabolic potential. How bacteria exploit host sialic acids includes a surprisingly complex array of metabolic and regulatory capabilities that is just now entering a mature research stage. This paper attempts to describe the variety of bacterial sialometabolic systems by focusing on recent advances at the molecular and host-microbe-interaction levels. The hope is that this focus will provide a framework for further research that holds promise for better understanding of the metabolic interplay between bacterial growth and the host environment. An ability to modify or block this interplay has already yielded important new insights into potentially new therapeutic approaches for modifying or blocking bacterial colonization or infection. PMID:23724337

  1. Mechanism of gallic acid biosynthesis in bacteria (Escherichia coli) and walnut (Juglans regia).

    PubMed

    Muir, Ryann M; Ibáñez, Ana M; Uratsu, Sandra L; Ingham, Elizabeth S; Leslie, Charles A; McGranahan, Gale H; Batra, Neelu; Goyal, Sham; Joseph, Jorly; Jemmis, Eluvathingal D; Dandekar, Abhaya M

    2011-04-01

    Gallic acid (GA), a key intermediate in the synthesis of plant hydrolysable tannins, is also a primary anti-inflammatory, cardio-protective agent found in wine, tea, and cocoa. In this publication, we reveal the identity of a gene and encoded protein essential for GA synthesis. Although it has long been recognized that plants, bacteria, and fungi synthesize and accumulate GA, the pathway leading to its synthesis was largely unknown. Here we provide evidence that shikimate dehydrogenase (SDH), a shikimate pathway enzyme essential for aromatic amino acid synthesis, is also required for GA production. Escherichia coli (E. coli) aroE mutants lacking a functional SDH can be complemented with the plant enzyme such that they grew on media lacking aromatic amino acids and produced GA in vitro. Transgenic Nicotiana tabacum lines expressing a Juglans regia SDH exhibited a 500% increase in GA accumulation. The J. regia and E. coli SDH was purified via overexpression in E. coli and used to measure substrate and cofactor kinetics, following reduction of NADP(+) to NADPH. Reversed-phase liquid chromatography coupled to electrospray mass spectrometry (RP-LC/ESI-MS) was used to quantify and validate GA production through dehydrogenation of 3-dehydroshikimate (3-DHS) by purified E. coli and J. regia SDH when shikimic acid (SA) or 3-DHS were used as substrates and NADP(+) as cofactor. Finally, we show that purified E. coli and J. regia SDH produced GA in vitro. PMID:21279669

  2. [Effects of a lactic acid bacteria community SFC-2 treated on rice straw].

    PubMed

    Gao, Li-Juan; Wang, Xiao-Fen; Yang, Hong-Yan; Gao, Xiu-Zhi; Lü, Yu-Cai; Cui, Zong-Jun

    2007-06-01

    Aimed to utilize rice straw and lessen the pressure of environment, the rice straw was used as the fermentation material, and a lactic acid bacteria community SFC-2 from my laboratory was inoculated into the rice straw to investigate the inoculation effects. After 30 days fermentation, the inoculated fermented straw smelt acid-fragrant, and the pH value was 3.8, which was lower than the control of 4.1. Furthermore, lactic acid concentration was more than that in the control. Especially L-lactic acid concentration was two times more than in the control, and the crude protein content was 10.16% higher than that in the control, and the crude fiber content was 3.2% lower than that in the control. From the patterns of denaturing gradient gel electrophoresis (DGGE), Lactobacillus plantarum, Lactobacillus fermentum and Lactobacillus paracasei rapidly became the advantageous species in the inoculated straws. However, Enterobacter sakazakii, Pantoea agglomerans, Enterobacter endosymbiont, Pantoea ananatis, whichwere predominate in the controls, were not detected in the inoculated straws, and the fermented quality was improved significantly. PMID:17674756

  3. Cholesterol assimilation by lactic acid bacteria and bifidobacteria isolated from the human gut.

    PubMed

    Pereira, Dora I A; Gibson, Glenn R

    2002-09-01

    The objective of this study was to evaluate the effect of human gut-derived lactic acid bacteria and bifidobacteria on cholesterol levels in vitro. Continuous cultures inoculated with fecal material from healthy human volunteers with media supplemented with cholesterol and bile acids were used to enrich for potential cholesterol assimilators among the indigenous bacterial populations. Seven potential probiotics were found: Lactobacillus fermentum strains F53 and KC5b, Bifidobacterium infantis ATCC 15697, Streptococcus bovis ATCC 43143, Enterococcus durans DSM 20633, Enterococcus gallinarum, and Enterococcus faecalis. A comparative evaluation regarding the in vitro cholesterol reduction abilities of these strains along with commercial probiotics was undertaken. The degree of acid and bile tolerance of strains was also evaluated. The human isolate L. fermentum KC5b was able to maintain viability for 2 h at pH 2 and to grow in a medium with 4,000 mg of bile acids per liter. This strain was also able to remove a maximum of 14.8 mg of cholesterol per g (dry weight) of cells from the culture medium and therefore was regarded as a candidate probiotic. PMID:12200334

  4. Inverse metabolic engineering based on transient acclimation of yeast improves acid-containing xylose fermentation and tolerance to formic and acetic acids.

    PubMed

    Hasunuma, Tomohisa; Sakamoto, Takatoshi; Kondo, Akihiko

    2016-01-01

    Improving the production of ethanol from xylose is an important goal in metabolic engineering of Saccharomyces cerevisiae. Furthermore, S. cerevisiae must produce ethanol in the presence of weak acids (formate and acetate) generated during pre-treatment of lignocellulosic biomass. In this study, weak acid-containing xylose fermentation was significantly improved using cells that were acclimated to the weak acids during pre-cultivation. Transcriptome analyses showed that levels of transcripts for transcriptional/translational machinery-related genes (RTC3 and ANB1) were enhanced by formate and acetate acclimation. Recombinant yeast strains overexpressing RTC3 and ANB1 demonstrated improved ethanol production from xylose in the presence of the weak acids, along with improved tolerance to the acids. Novel metabolic engineering strategy based on the combination of short-term acclimation and system-wide analysis was developed, which can develop stress-tolerant strains in a short period of time, although conventional evolutionary engineering approach has required long periods of time to isolate inhibitor-adapted strains. PMID:26521247

  5. Changes in composition and amino acid profile during dry grind ethanol processing from corn and estimation of yeast contribution toward DDGS proteins.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three sets of ground corn, yeast, intermediate masses and DDGS were collected from three commercial ethanol plants in Iowa. Samples were freeze-dried before chemical analysis. Compared to ground corn, there was slight increase in contents of protein, oil, ash, and amino acids (AA) before fermentati...

  6. Evaluation of epidemiological studies of intestinal bacteria that affected occurrence of colorectal cancer: studies of prevention of colorectal tumors by dairy products and lactic acid bacteria.

    PubMed

    Kawano, Atsuko; Ishikawa, Hideki; Nakamura, Tomiyo; Kono, Koichi

    2010-05-01

    Enviromental factors have been consistently associated with colon cancer risk. In particular, consumption of Western-style diet including red meat is the most widely accepted etiologic risk factor. It has been reported that dietary factors change the proportion of intestinal flora, and it also affects the composition of fecal bile acids and the intestinal activity of some mutagens. In addition, it was suggested that modulating the composition of intestinal flora may reduce the occurrence of colorectal cancer. In this review, we present the clinical studies on the association between intestinal flora and the risk of colorectal cancer that have been carried out to date. The clinical studies of intestinal bacteria related to colorectal cancer risk have not shown consistent results so far, compared with the accomplishments of some basic studies. On the other hand, it was suggested in some clinical studies that lactic acid bacteria reduce the occurrence of colorectal cancer. PMID:20508386

  7. Marine yeasts as biocontrol agents and producers of bio-products.

    PubMed

    Chi, Zhen-Ming; Liu, Guanglei; Zhao, Shoufeng; Li, Jing; Peng, Ying

    2010-05-01

    As some species of marine yeasts can colonize intestine of marine animals, they can be used as probiotics. It has been reported that beta-glucans from marine yeast cells can be utilized as immuno-stimulants in marine animals. Some siderophores or killer toxins produced by marine yeasts have ability to inhibit growth of pathogenic bacteria or kill pathogenic yeasts in marine animals. The virulent factors from marine pathogens can be genetically displayed on marine yeast cells, and the yeast cells displaying the virulent factors can stimulate marine animals to produce specific antibody against the pathogens. Some marine yeast cells are rich in proteins and essential amino acids and can be used in nutrition for marine animals. The marine yeast cells rich in lipid can be used for biodiesel production. Recently, it has been reported that some strains of Yarrowia lipolytica isolated from marine environments can produce nanoparticles. Because many marine yeasts can remove organic pollutants and heavy metals, they can be applied to remediation of marine environments. It has been shown that the enzymes produced by some marine yeasts have many unique properties and many potential applications. PMID:20195858

  8. In situ biodegradation of naphthenic acids in oil sands tailings pond water using indigenous algae-bacteria consortium.

    PubMed

    Mahdavi, Hamed; Prasad, Vinay; Liu, Yang; Ulrich, Ania C

    2015-01-01

    In this study, the biodegradation of total acid-extractable organics (TAOs), commonly called naphthenic acids (NAs), was investigated. An indigenous microbial culture containing algae and bacteria was taken from the surface of a tailings pond and incubated over the course of 120days. The influence of light, oxygen and the presence of indigenous algae and bacteria, and a diatom (Navicula pelliculosa) on the TAO removal rate were elucidated. The highest biodegradation rate was observed with bacteria growth only (without light exposure) with a half-life (t(1/2)) of 203days. The algae-bacteria consortium enhanced the detoxification process, however, bacterial biomass played the main role in toxicity reduction. Principal component analysis (PCA) conducted on FT-IR spectra, identified functional groups and bonds (representing potential markers for biotransformation of TAOs) as follows: hydroxyl, carboxyl and amide groups along with CH, arylH, arylOH and NH bonds. PMID:25841188

  9. The cell membrane and the struggle for life of lactic acid bacteria.

    PubMed

    Konings, Wil N

    2002-08-01

    The major life-threatening event for lactic acid bacteria (LAB) in their natural environment is the depletion of their energy sources and LAB can survive such conditions only for a short period of time. During periods of starvation LAB can exploit optimally the potential energy sources in their environment usually by applying proton motive force generating membrane transport systems. These systems include in addition to the proton translocating F0F1-ATPase: a respiratory chain when hemin is present in the medium, electrogenic solute uptake and excretion systems, electrogenic lactate/proton symport and precursor/product exchange systems. Most of these metabolic energy-generating systems offer as additional bonus the prevention of a lethal decrease of the internal and external pH. LAB have limited biosynthetic capacities and rely heavily on the presence of essential components such as sources of amino acids in their environment. The uptake of amino acids requires a major fraction of the available metabolic energy of LAB. The metabolic energy cost of amino acid uptake can be reduced drastically by accumulating oligopeptides instead of the individual amino acids and by proton motive force-generating efflux of excessively accumulated amino acids. Other life-threatening conditions that LAB encounter in their environment are rapid changes in the osmolality and the exposure to cytotoxic compounds, including antibiotics. LAB respond to osmotic upshock or downshock by accumulating or releasing rapidly osmolytes such as glycine-betaine. The life-threatening presence of cytotoxic compounds, including antibiotics, is effectively counteracted by powerful drug extruding multidrug resistance systems. The number and variety of defense mechanisms in LAB is surprisingly high. Most defense mechanisms operate in the cytoplasmic membrane to control the internal environment and the energetic status of LAB. Annotation of the functions of the genes in the genomes of LAB will undoubtedly

  10. Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite

    PubMed Central

    Moreau, Jennifer L.; Sun, Limin; Chow, Laurence C.; Xu, Hockin H. K.

    2012-01-01

    Dental composites do not hinder bacteria colonization and plaque formation. Caries at the restoration margins is a frequent reason for replacement of existing restorations, which accounts for 50 to 70% of all restorations. The objectives of this study were to examine the filler level effect on nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and investigate the load-bearing and acid-neutralizing properties and bacteria inhibition. NACP with 116-nm particle size were synthesized via a spray-drying technique and incorporated into a resin. Flexural strength of nanocomposite with 10 to 30% NACP fillers matched the strength of a commercial hybrid composite (p > 0.1). Nanocomposite with 40% NACP matched the strength of a microfill composite, which was 2-fold that of a resin-modified glass ionomer. Nanocomposite with 40% NACP neutralized a lactic acid solution of pH 4 by rapidly increasing the pH to 5.69 in 10 min. In contrast, the commercial controls had pH staying at near 4. Using Streptoccocus mutans, an agar disk-diffusion test showed no inhibition zone for commercial controls. In contrast, the inhibition zone was (2.5 ± 0.7) mm for nanocomposite with 40% NACP. Crystal violet staining showed that S. mutans coverage on nanocomposite was 1/4 that on commercial composite. In conclusion, novel calcium–phosphate nanocomposite matched the mechanical properties of commercial composite and rapidly neutralized lactic acid of pH 4. The nanocomposite appeared to moderately reduce the S. mutans growth, and further study is needed to obtain strong antimicrobial properties. The new nanocomposite may have potential to reduce secondary caries and restoration fracture, two main challenges facing tooth cavity restorations. PMID:21504057

  11. Mechanical and acid neutralizing properties and bacteria inhibition of amorphous calcium phosphate dental nanocomposite.

    PubMed

    Moreau, Jennifer L; Sun, Limin; Chow, Laurence C; Xu, Hockin H K

    2011-07-01

    Dental composites do not hinder bacteria colonization and plaque formation. Caries at the restoration margins is a frequent reason for replacement of existing restorations, which accounts for 50 to 70% of all restorations. The objectives of this study were to examine the filler level effect on nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) and investigate the load-bearing and acid-neutralizing properties and bacteria inhibition. NACP with 116-nm particle size were synthesized via a spray-drying technique and incorporated into a resin. Flexural strength of nanocomposite with 10 to 30% NACP fillers matched the strength of a commercial hybrid composite (p > 0.1). Nanocomposite with 40% NACP matched the strength of a microfill composite, which was 2-fold that of a resin-modified glass ionomer. Nanocomposite with 40% NACP neutralized a lactic acid solution of pH 4 by rapidly increasing the pH to 5.69 in 10 min. In contrast, the commercial controls had pH staying at near 4. Using Streptoccocus mutans, an agar disk-diffusion test showed no inhibition zone for commercial controls. In contrast, the inhibition zone was (2.5 ± 0.7) mm for nanocomposite with 40% NACP. Crystal violet staining showed that S. mutans coverage on nanocomposite was 1/4 that on commercial composite. In conclusion, novel calcium-phosphate nanocomposite matched the mechanical properties of commercial composite and rapidly neutralized lactic acid of pH 4. The nanocomposite appeared to moderately reduce the S. mutans growth, and further study is needed to obtain strong antimicrobial properties. The new nanocomposite may have potential to reduce secondary caries and restoration fracture, two main challenges facing tooth cavity restorations. PMID:21504057

  12. One carbon metabolism in anaerobic bacteria: Regulation of carbon and electron flow during organic acid production

    SciTech Connect

    Zeikus, J.G.; Jain, M.

    1993-12-31

    The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen metabolism by fermentation, enzyme, and electron carrier analysis using Butyribacterium methylotrophicum, Anaeroblospirillum succiniciproducens, Methanosarcina barkeri, and a newly isolated tri-culture composed of a syntrophic butyrate degrader strain IB, Methanosarcina mazei and Methanobacterium formicicum as model systems. To understand the regulation of hydrogen metabolism during butyrate production or acetate degradation, hydrogenase activity in B. methylotrophicum or M. barkeri is measured in relation to growth substrate and pH; hydrogenase is purified and characterized to investigate number of hydrogenases; their localization and functions; and, their sequences are determined. To understand the mechanism for catabolic CO{sub 2} fixation to succinate the PEP carboxykinase enzyme and gene of A. succiniciproducens are purified and characterized. Genetically engineered strains of Escherichia coli containing the phosphoenolpyruvate (PEP) carboxykinase gene are examined for their ability to produce succinate in high yield. To understand the mechanism of fatty acid degradation by syntrophic acetogens during mixed culture methanogenesis formate and hydrogen production are characterized by radio tracer studies. It is intended that these studies provide strategies to improve anaerobic fermentations used for the production of organic acids or methane and, new basic understanding on catabolic CO{sub 2} fixation mechanisms and on the function of hydrogenase in anaerobic bacteria.

  13. Comparative Genomics of Syntrophic Branched-Chain Fatty Acid Degrading Bacteria

    PubMed Central

    Narihiro, Takashi; Nobu, Masaru K.; Tamaki, Hideyuki; Kamagata, Yoichi; Sekiguchi, Yuji; Liu, Wen-Tso

    2016-01-01

    The syntrophic degradation of branched-chain fatty acids (BCFAs) such as 2-methylbutyrate and isobutyrate is an essential step in the production of methane from proteins/amino acids in anaerobic ecosystems. While a few syntrophic BCFA-degrading bacteria have been isolated, their metabolic pathways in BCFA and short-chain fatty acid (SCFA) degradation as well as energy conservation systems remain unclear. In an attempt to identify these pathways, we herein performed comparative genomics of three syntrophic bacteria: 2-methylbutyrate-degrading “Syntrophomonas wolfei subsp. methylbutyratica” strain JCM 14075T (=4J5T), isobutyrate-degrading Syntrophothermus lipocalidus strain TGB-C1T, and non-BCFA-metabolizing S. wolfei subsp. wolfei strain GöttingenT. We demonstrated that 4J5 and TGB-C1 both encode multiple genes/gene clusters involved in β-oxidation, as observed in the Göttingen genome, which has multiple copies of genes associated with butyrate degradation. The 4J5 genome possesses phylogenetically distinct β-oxidation genes, which may be involved in 2-methylbutyrate degradation. In addition, these Syntrophomonadaceae strains harbor various hydrogen/formate generation systems (i.e., electron-bifurcating hydrogenase, formate dehydrogenase, and membrane-bound hydrogenase) and energy-conserving electron transport systems, including electron transfer flavoprotein (ETF)-linked acyl-CoA dehydrogenase, ETF-linked iron-sulfur binding reductase, ETF dehydrogenase (FixABCX), and flavin oxidoreductase-heterodisulfide reductase (Flox-Hdr). Unexpectedly, the TGB-C1 genome encodes a nitrogenase complex, which may function as an alternative H2 generation mechanism. These results suggest that the BCFA-degrading syntrophic strains 4J5 and TGB-C1 possess specific β-oxidation-related enzymes for BCFA oxidation as well as appropriate energy conservation systems to perform thermodynamically unfavorable syntrophic metabolism. PMID:27431485

  14. Bioconversion of Raw Glycerol Generated from the Synthesis of Biodiesel by Different Oleaginous Yeasts: Lipid Content and Fatty Acid Profile of Biomass.

    PubMed

    Spier, Franciela; Buffon, Jaqueline G; Burkert, Carlos A V

    2015-12-01

    In this work, 12 different yeast strains were evaluated to gauge their ability to accumulate lipids using raw glycerol as the main carbon source. Lipomyces lipofer NRRL Y-1155 stood out above the other strains, achieving 9.48 g/l biomass, 57.64 % lipid content and 5.46 g/l lipid production. The fatty acid profile was similar to vegetable oils commonly used in the synthesis of biodiesel, with the predominance of polyunsaturated acids, especially linoleic acid, reaching 68.3 % for Rhodotorula glutinis NRRL YB-252. The occurrence of palmitic acid (39.3 % for Lipomyces starkeyi NRRL Y-11557) was also notable. Thus, yeast biomass with high lipid content can be a sustainable and renewable alternative as a raw material for the biodiesel industry. PMID:26543267

  15. Dysfunction of organic anion transporting polypeptide 1a1 alters intestinal bacteria and bile acid metabolism in mice.

    PubMed

    Zhang, Youcai; Limaye, Pallavi B; Lehman-McKeeman, Lois D; Klaassen, Curtis D

    2012-01-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

  16. Dysfunction of Organic Anion Transporting Polypeptide 1a1 Alters Intestinal Bacteria and Bile Acid Metabolism in Mice

    PubMed Central

    Zhang, Youcai; Limaye, Pallavi B.; Lehman-McKeeman, Lois D.; Klaassen, Curtis D.

    2012-01-01

    Organic anion transporting polypeptide 1a1 (Oatp1a1) is predominantly expressed in liver and is able to transport bile acids (BAs) in vitro. Male Oatp1a1-null mice have increased concentrations of taurodeoxycholic acid (TDCA), a secondary BA generated by intestinal bacteria, in both serum and livers. Therefore, in the present study, BA concentrations and intestinal bacteria in wild-type (WT) and Oatp1a1-null mice were quantified to investigate whether the increase of secondary BAs in Oatp1a1-null mice is due to alterations in intestinal bacteria. The data demonstrate that Oatp1a1-null mice : (1) have similar bile flow and BA concentrations in bile as WT mice; (2) have a markedly different BA composition in the intestinal contents, with a decrease in conjugated BAs and an increase in unconjugated BAs; (3) have BAs in the feces that are more deconjugated, desulfated, 7-dehydroxylated, 3-epimerized, and oxidized, but less 7-epimerized; (4) have 10-fold more bacteria in the small intestine, and 2-fold more bacteria in the large intestine which is majorly due to a 200% increase in Bacteroides and a 30% reduction in Firmicutes; and (5) have a different urinary excretion of bacteria-related metabolites than WT mice. In conclusion, the present study for the first time established that lack of a liver transporter (Oatp1a1) markedly alters the intestinal environment in mice, namely the bacteria composition. PMID:22496825

  17. Modelling the effect of lactic acid bacteria from starter- and aroma culture on growth of Listeria monocytogenes in cottage cheese.

    PubMed

    Østergaard, Nina Bjerre; Eklöw, Annelie; Dalgaard, Paw

    2014-10-01

    Four mathematical models were developed and validated for simultaneous growth of mesophilic lactic acid bacteria from added cultures and Listeria monocytogenes, during chilled storage of cottage cheese with fresh- or cultured cream dressing. The mathematical models include the effect of temperature, pH, NaCl, lactic- and sorbic acid and the interaction between these environmental factors. Growth models were developed by combining new and existing cardinal parameter values. Subsequently, the reference growth rate parameters (μref at 25°C) were fitted to a total of 52 growth rates from cottage cheese to improve model performance. The inhibiting effect of mesophilic lactic acid bacteria from added cultures on growth of L. monocytogenes was efficiently modelled using the Jameson approach. The new models appropriately predicted the maximum population density of L. monocytogenes in cottage cheese. The developed models were successfully validated by using 25 growth rates for L. monocytogenes, 17 growth rates for lactic acid bacteria and a total of 26 growth curves for simultaneous growth of L. monocytogenes and lactic acid bacteria in cottage cheese. These data were used in combination with bias- and accuracy factors and with the concept of acceptable simulation zone. Evaluation of predicted growth rates of L. monocytogenes in cottage cheese with fresh- or cultured cream dressing resulted in bias-factors (Bf) of 1.07-1.10 with corresponding accuracy factor (Af) values of 1.11 to 1.22. Lactic acid bacteria from added starter culture were on average predicted to grow 16% faster than observed (Bf of 1.16 and Af of 1.32) and growth of the diacetyl producing aroma culture was on average predicted 9% slower than observed (Bf of 0.91 and Af of 1.17). The acceptable simulation zone method showed the new models to successfully predict maximum population density of L. monocytogenes when growing together with lactic acid bacteria in cottage cheese. 11 of 13 simulations of L</