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Sample records for acid production rate

  1. High Acetic Acid Production Rate Obtained by Microbial Electrosynthesis from Carbon Dioxide.

    PubMed

    Jourdin, Ludovic; Grieger, Timothy; Monetti, Juliette; Flexer, Victoria; Freguia, Stefano; Lu, Yang; Chen, Jun; Romano, Mark; Wallace, Gordon G; Keller, Jurg

    2015-11-17

    High product specificity and production rate are regarded as key success parameters for large-scale applicability of a (bio)chemical reaction technology. Here, we report a significant performance enhancement in acetate formation from CO2, reaching comparable productivity levels as in industrial fermentation processes (volumetric production rate and product yield). A biocathode current density of -102 ± 1 A m(-2) and an acetic acid production rate of 685 ± 30 (g m(-2) day(-1)) have been achieved in this study. High recoveries of 94 ± 2% of the CO2 supplied as the sole carbon source and 100 ± 4% of electrons into the final product (acetic acid) were achieved after development of a mature biofilm, reaching an elevated product titer of up to 11 g L(-1). This high product specificity is remarkable for mixed microbial cultures, which would make the product downstream processing easier and the technology more attractive. This performance enhancement was enabled through the combination of a well-acclimatized and enriched microbial culture (very fast start-up after culture transfer), coupled with the use of a newly synthesized electrode material, EPD-3D. The throwing power of the electrophoretic deposition technique, a method suitable for large-scale production, was harnessed to form multiwalled carbon nanotube coatings onto reticulated vitreous carbon to generate a hierarchical porous structure. PMID:26484732

  2. Measurement and Analysis of Extracellular Acid Production to Determine Glycolytic Rate.

    PubMed

    Mookerjee, Shona A; Brand, Martin D

    2015-01-01

    Extracellular measurement of oxygen consumption and acid production is a simple and powerful way to monitor rates of respiration and glycolysis(1). Both mitochondrial (respiration) and non-mitochondrial (other redox) reactions consume oxygen, but these reactions can be easily distinguished by chemical inhibition of mitochondrial respiration. However, while mitochondrial oxygen consumption is an unambiguous and direct measurement of respiration rate(2), the same is not true for extracellular acid production and its relationship to glycolytic rate (3-6). Extracellular acid produced by cells is derived from both lactate, produced by anaerobic glycolysis, and CO2, produced in the citric acid cycle during respiration. For glycolysis, the conversion of glucose to lactate(-) + H(+) and the export of products into the assay medium is the source of glycolytic acidification. For respiration, the export of CO2, hydration to H2CO3 and dissociation to HCO3(-) + H(+) is the source of respiratory acidification. The proportions of glycolytic and respiratory acidification depend on the experimental conditions, including cell type and substrate(s) provided, and can range from nearly 100% glycolytic acidification to nearly 100% respiratory acidification (6). Here, we demonstrate the data collection and calculation methods needed to determine respiratory and glycolytic contributions to total extracellular acidification by whole cells in culture using C2C12 myoblast cells as a model. PMID:26709455

  3. Decomposition of phenylarsonic acid by AOP processes: degradation rate constants and by-products.

    PubMed

    Jaworek, K; Czaplicka, M; Bratek, Ł

    2014-10-01

    The paper presents results of the studies photodegradation, photooxidation, and oxidation of phenylarsonic acid (PAA) in aquatic solution. The water solutions, which consist of 2.7 g dm(-3) phenylarsonic acid, were subjected to advance oxidation process (AOP) in UV, UV/H2O2, UV/O3, H2O2, and O3 systems under two pH conditions. Kinetic rate constants and half-life of phenylarsonic acid decomposition reaction are presented. The results from the study indicate that at pH 2 and 7, PAA degradation processes takes place in accordance with the pseudo first order kinetic reaction. The highest rate constants (10.45 × 10(-3) and 20.12 × 10(-3)) and degradation efficiencies at pH 2 and 7 were obtained at UV/O3 processes. In solution, after processes, benzene, phenol, acetophenone, o-hydroxybiphenyl, p-hydroxybiphenyl, benzoic acid, benzaldehyde, and biphenyl were identified. PMID:24824504

  4. Pickled egg production: effect of brine acetic acid concentration and packing conditions on acidification rate.

    PubMed

    Acosta, Oscar; Gao, Xiaofan; Sullivan, Elizabeth K; Padilla-Zakour, Olga I

    2014-05-01

    U.S. federal regulations require that acidified foods must reach a pH of 4.6 or lower within 24 h of packaging or be kept refrigerated until then. Processes and formulations should be designed to satisfy this requirement, unless proper studies demonstrate the safety of other conditions. Our objective was to determine the effect of brine acetic acid concentration and packing conditions on the acidification rate of hard-boiled eggs. Eggs were acidified (60/40 egg-to-brine ratio) at various conditions of brine temperature, heat treatment to filled jars, and postpacking temperature: (i) 25 °C/none/25 °C (cold fill), (ii) 25 °C/none/2 °C (cold fill/refrigerated), (iii) 85 °C/none/25 °C (hot fill), and (iv) 25 °C/100 °C for 16 min/25 °C (water bath). Three brine concentrations were evaluated (7.5, 4.9, and 2.5% acetic acid) and egg pH values (whole, yolk, four points within egg) were measured from 4 to 144 h, with eggs equilibrating at pH 3.8, 4.0, and 4.3, respectively. Experiments were conducted in triplicate, and effects were considered significant when P < 0.05. Multiple linear regression analysis was conducted to evaluate the effect on pH values at the center of the yolk. Regression analysis showed that brine concentration of 2.5% decreased the acidification rate, while packing conditions of the hot fill trial increased it. Inverse prediction was used to determine the time for the center of the yolk and the total yolk to reach a pH value of 4.6. These results demonstrate the importance of conducting acidification studies with proper pH measurements to determine safe conditions to manufacture commercially stable pickled eggs. PMID:24780334

  5. Seasonal Changes in Mycosporine-Like Amino Acid Production Rate with Respect to Natural Phytoplankton Species Composition

    PubMed Central

    Ha, Sun-Yong; Lee, Yeonjung; Kim, Min-Seob; Kumar, K. Suresh; Shin, Kyung-Hoon

    2015-01-01

    After in situ incubation at the site for a year, phytoplanktons in surface water were exposed to natural light in temperate lakes (every month); thereafter, the net production rate of photoprotective compounds (mycosporine-like amino acids, MAAs) was calculated using 13C labeled tracer. This is the first report describing seasonal variation in the net production rate of individual MAAs in temperate lakes using a compound-specific stable isotope method. In the mid-latitude region of the Korean Peninsula, UV radiation (UVR) usually peaks from July to August. In Lake Paldang and Lake Cheongpyeong, diatoms dominated among the phytoplankton throughout the year. The relative abundance of Cyanophyceae (Anabaena spiroides) reached over 80% during July in Lake Cheongpyeong. Changes in phytoplankton abundance indicate that the phytoplankton community structure is influenced by seasonal changes in the net production rate and concentration of MAAs. Notably, particulate organic matter (POM) showed a remarkable change based on the UV intensity occurring during that period; this was because of the fact that cyanobacteria that are highly sensitive to UV irradiance dominated the community. POM cultured in Lake Paldang had the greatest shinorine (SH) production rate during October, i.e., 83.83 ± 10.47 fgC·L−1·h−1. The dominance of diatoms indicated that they had a long-term response to UVR. Evaluation of POM cultured in Lake Cheongpyeong revealed that there was an increase in the net MAA production in July (when UVR reached the maximum); a substantial amount of SH, i.e., 17.62 ± 18.34 fgC·L−1·h−1, was recorded during this period. Our results demonstrate that both the net production rate as well as the concentration of MAAs related to photoinduction depended on the phytoplankton community structure. In addition, seasonal changes in UVR also influenced the quantity and production of MAAs in phytoplanktons (especially Cyanophyceae). PMID:26561820

  6. Acidity variations across the cloud drop size spectrum and their influence on rates of atmospheric sulfate production

    SciTech Connect

    Collett, J.L. Jr.; Bator, A.; Rao, Xin; Demoz, B.

    1994-11-01

    Measurements of pH variations within natural cloud drop populations reveal that small drops are often more acidic than large drops. Cloud samples collected from coastal stratus clouds, frontal clouds, and radiation fogs, from heavily polluted and pristine locations, had pH values ranging from below three to more than seven. Differences between small and large cloud drop acidities as large as two pH units were observed, although differences were generally below one pH unit. This chemical heterogenity can significantly enhance oxidation of sulfur dioxide to sulfate within clouds, relative to oxidation rates predicted from the average cloudwater composition. One-third of the sampled clouds were estimated to experience an increase of at least 20% in the rate of sulfur oxidation by ozone (8% of the clouds had increases exceeding 100%) as a result of acidity differences between large and small cloud drops. These findings suggest that sulfate production within clouds, a critical component of the global sulfur cycle, may be more rapid than previously though. 20 refs., 3 figs.

  7. Bile acid production in human subjects: rate of oxidation of (24,25-/sup 3/H)cholesterol compared to fecal bile acid excretion

    SciTech Connect

    Davidson, N.O.; Bradlow, H.L.; Ahrens, E.H. Jr.; Rosenfeld, R.S.; Schwartz, C.C.

    1986-02-01

    Bile acid production has been quantitated in seven subjects by methods that compare the results of two independent approaches, namely, quantitation of cholesterol side-chain oxidation and fecal bile acid excretion. Six hypertriglyceridemic (HT) subjects and one normolipidemic control were studied by both techniques. A further control subject was studied by the cholesterol side-chain oxidation method alone. Cholesterol side-chain oxidation was quantitated by measuring the appearance of /sup 3/H/sub 2/O after intravenous administration of (24,25-/sup 3/H)cholesterol, using multicompartmental analysis of plasma cholesterol and (/sup 3/H)water specific activity. Body water kinetics were independently defined by use of oral D/sub 2/O. Two HT subjects were restudied while they were taking cholestyramine, 16 g/day. In all ten studies, multicompartmental analysis closely simulated the observed appearance of /sup 3/H/sub 2/O. Values obtained for bile acid production suggest that cholesterol oxidation, or bile acid input, was significantly greater than fecal bile acid output in the HT subjects (P less than 0.05). Cholesterol side-chain oxidation rates in the two normal subjects were lower than those encountered in HT subjects, being similar to published values for normal subjects both for bile acid synthesis as determined by isotope dilution kinetics and fecal bile acid excretion. Studies conducted with two, synthetically different, preparations of (24,25-/sup 3/H)cholesterol indicated that, in one of the two preparations, approximately 20% of the tritium label was at positions proximal to C24. In the other preparation examined, all of the tritium was located at, or distal to, C24. Further studies revealed that 0.055-0.24% of the dose was present as labile tritium by virtue of its appearance as /sup 3/H/sub 2/O following in vitro incubation with human plasma. (Abstract Truncated)

  8. Potential Link Between Contents of Fatty Acids and Soybean Seed Germination Rate Under Early Production System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean seed produced from the Early Soybean Production System (ESPS) in the Midsouth often has low germination with poor seed quality. The mechanism of this phenomenon is not clear. A field study was conducted in 2008 and 2009 on a silt-loam -soil at the Delta Research and Extension Center, Stonevi...

  9. High-rate volatile fatty acid (VFA) production by a granular sludge process at low pH.

    PubMed

    Tamis, J; Joosse, B M; Loosdrecht, M C M van; Kleerebezem, R

    2015-11-01

    Volatile fatty acids (VFA) are proposed platform molecules for the production of basic chemicals and polymers from organic waste streams. In this study we developed a granular sludge process to produce VFA at high rate, yield and purity while minimizing potential operational costs. A lab-scale anaerobic sequencing batch reactor (ASBR) was fed with 10 g l(-1) glucose as model substrate. Inclusion of a short (2 min) settling phase before effluent discharge enabled effective granulation and very high volumetric conversion rates of 150-300 gCOD l(-1)  d(-1) were observed during glucose conversion. The product spectrum remained similar at the tested pH range with acetate and butyrate as the main products, and a total VFA yield of 60-70% on chemical oxygen demand (COD) basis. The requirement for base addition for pH regulation could be reduced from 1.1 to 0.6 mol OH(-) (mol glucose)(-1) by lowering the pH from 5.5 to 4.5. Solids concentrations in the effluent were 0.6 ± 0.3 g l(-1) but could be reduced to 0.02 ± 0.01 g l(-1) by introduction of an additional settling period of 5 min. The efficient production of VFA at low pH with a virtually solid-free effluent increases the economic feasibility of waste-based chemicals and polymer production. Biotechnol. PMID:25950759

  10. A comparison of three pH control methods for revealing effects of undissociated butyric acid on specific butanol production rate in batch fermentation of Clostridium acetobutylicum

    PubMed Central

    2013-01-01

    pH control has been essential for butanol production with Clostridium acetobutylicum. However, it is not very clear at what pH level the acid crash will occur, at what pH level butanol production will be dominant, and at what pH level butyric acid production will be prevailing. Furthermore, contradictory results have been reported about required acidic conditions for initiation of solventogenesis. In this study, with the aim of further understanding the role of undissociated butyric acid in butanol production, we investigated the correlation between undissociated butyric acid concentration and specific butanol production rate in batch fermentation of Clostridium acetobutylicum by comparing three pH control approaches: NaOH neutralization (at 12, 24 or 36 h), CaCO3 supplementation (2, 5, or 8 g/l) and NaOAc buffering (pH 4.6, 5.0 or 5.6). By neutralizing the fermentation pH to ~5.0 at different time, we observed that neutralization should take place at the beginning of exponential phase (12 h), and otherwise resulting in lower concentrations of undissociated butyric acid, cell biomass and final butanol. CaCO3 supplementation extended cell growth to 36 h and resulted in higher butyrate yield under 8 g/L of CaCO3. In the NaOAc buffering, the highest specific butanol rate (0.58 h−1) was associated with the highest undissociated butyric acid (1.92 g/L). The linear correlation of the undissociated butyric acid with the specific butanol production rates suggested the undissociated butyric acid could be the major driving force for butanol production. PMID:23294525

  11. Changes in ruminal volatile fatty acid production and absorption rate during the dry period and early lactation as affected by rate of increase of concentrate allowance.

    PubMed

    Dieho, K; Dijkstra, J; Schonewille, J T; Bannink, A

    2016-07-01

    The aim of the present experiment was to study changes in volatile fatty acid (VFA) production using an isotope dilution technique, and changes in VFA fractional absorption rate (kaVFA) using a buffer incubation technique (BIT) during the dry period and early lactation, as affected by the postpartum (pp) rate of increase of concentrate allowance. The current results are complementary to previously reported changes on rumen papillae morphology from the same experiment. From 50 d antepartum to 80 d pp, VFA production rate was measured 5 times and kaVFA was measured 10 times in 12 rumen-cannulated Holstein Friesian cows. Cows had free access to a mixed ration, consisting of grass and corn silage, soybean meal, and (dry period only) chopped straw. Treatment consisted of either a rapid (RAP; 1.0 kg of DM/d; n=6) or gradual (GRAD; 0.25 kg of DM/d; n=6) increase of concentrate allowance (up to 10.9 kg of DM/d), starting at 4 d pp, aimed at creating a contrast in rumen-fermentable organic matter intake. For the BIT, rumen contents were evacuated, the rumen washed, and a standardized buffer fluid introduced [120 mM VFA, 60% acetic (Ac), 25% propionic (Pr), and 15% butyric (Bu) acid; pH 5.9 and Co-EDTA as fluid passage marker]. For the isotope dilution technique, a pulse-dose of (13)C-labeled Ac, Pr, and Bu and Co-EDTA as fluid passage marker was infused. The rate of total VFA production was similar between treatments and was 2 times higher during the lactation (114 mol/d) than the dry period (53 mol/d). Although papillae surface area at 16, 30, and 44 d pp was greater in RAP than GRAD, Bu and Ac production at these days did not differ between RAP and GRAD, whereas at 16 d pp RAP produced more Pr than GRAD. These results provide little support for the particular proliferative effects of Bu on papillae surface area. Similar to developments in papillae surface area in the dry period and early lactation, the kaVFA (per hour), measured using the BIT, decreased from 0.45 (Ac), 0

  12. PRODUCTION OF TRIFLUOROACETIC ACID

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-07-19

    A method is given for the production of improved yields of trifluoroacetic acid. The compound is prepared by oxidizing m-aminobenzotrifluoride with an alkali metal or alkaline earth metal permanganate at a temperature in the range of 80 deg C to 100 deg C while dissolved ln a mixture of water with glacial acetic acid and/or trifluoroacetic acid. Preferably a mixture of water and trifluoroacetic acid ls used as the solvent.

  13. Optimization of Aeration and Agitation Rate for Lipid and Gamma Linolenic Acid Production by Cunninghamella bainieri 2A1 in Submerged Fermentation Using Response Surface Methodology

    PubMed Central

    Saad, Normah; Abdeshahian, Peyman; Kalil, Mohd Sahaid; Wan Yusoff, Wan Mohtar

    2014-01-01

    The locally isolated filamentous fungus Cunninghamella bainieri 2A1 was cultivated in a 5 L bioreactor to produce lipid and gamma-linolenic acid (GLA). The optimization was carried out using response surface methodology based on a central composite design. A statistical model, second-order polynomial model, was adjusted to the experimental data to evaluate the effect of key operating variables, including aeration rate and agitation speed on lipid production. Process analysis showed that linear and quadratic effect of agitation intensity significantly influenced lipid production process (P < 0.01). The quadratic model also indicated that the interaction between aeration rate and agitation speed had a highly significant effect on lipid production (P < 0.01). Experimental results showed that a lipid content of 38.71% was produced in optimum conditions using an airflow rate and agitation speed of 0.32 vvm and 599 rpm, respectively. Similar results revealed that 0.058 (g/g) gamma-linolenic acid was produced in optimum conditions where 1.0 vvm aeration rate and 441.45 rpm agitation rate were used. The regression model confirmed that aeration and agitation were of prime importance for optimum production of lipid in the bioreactor. PMID:25610901

  14. Production rate estimation of mycosporine-like amino acids in two Arctic melt ponds by stable isotope probing with NAH(13) CO3.

    PubMed

    Ha, Sun-Yong; Min, Jun-Oh; Joo, Hyun Min; Chung, Kyung Ho; Shin, Kyung-Hoon; Yang, EunJin; Kang, Sung-Ho

    2014-10-01

    The net carbon uptake rate and net production rate of mycosporine-like amino acids (MAAs) were measured in phytoplankton from 2 different melt ponds (MPs; closed and open type pond) in the western Arctic Ocean using a (13) C stable isotope tracer technique. The Research Vessel Araon visited ice-covered western-central basins situated at 82°N and 173°E in the summer of 2012, when Arctic sea ice declined to a record minimum. The average net carbon uptake rate of the phytoplankton in polycarbonate (PC) bottles in the closed MP was 3.24 mg C · m(-3) · h(-1) (SD = ±1.12 mg C · m(-3) · h(-1) ), while that in the open MP was 1.3 mg C · m(-3) · h(-1) (SD = ±0.05 mg C · m(-3) · h(-1) ). The net production rate of total MAAs in incubated PC bottles was highest (1.44 (SD = ±0.24) ng C · L(-1) · h(-1) ) in the open MP and lowest (0.05 (SD = ±0.003) ng C · L(-1) · h(-1) ) in the closed MP. The net production rate of shinorine and palythine in incubated PC bottles at the open MP presented significantly high values 0.76 (SD = ±0.12) ng C · L(-1) · h(-1) and 0.53 (SD = ±0.06) ng C · L(-1) · h(-1) . Our results showed that high net production rate of MAAs in the open MP was enhanced by a combination of osmotic and UVR stress and that in situ net production rates of individual MAA can be determined using (13) C tracer in MPs in Arctic sea ice. PMID:26988644

  15. Regio- and stereo-chemical oxidation of linoleic acid by human myoglobin and hydrogen peroxide: Tyr103 affects rate and product distribution

    PubMed Central

    2004-01-01

    Mb (myoglobin) plus H2O2 catalyses the oxidation of various substrates via a peroxidase-like activity. A Y103F (Tyr103→Phe) variant of human Mb has been constructed to assess the effect of exchanging an electron-rich oxidizable amino acid on the peroxidase activity of human Mb. Steady-state analyses of reaction mixtures containing Y103F Mb, purified linoleic acid and H2O2 revealed a lower total yield of lipid oxidation products than mixtures containing the wild-type protein, consistent with the reported decrease in the rate constant for reaction of Y103F Mb with H2O2 [Witting, Mauk and Lay (2002) Biochemistry 41, 11495–11503]. Irrespective of the Mb employed, lipid oxidation yielded 9(R/S)-HODE [9(R,S)-hydroxy-10E,12Z-octadecadienoic acid] in preference to 13(R/S)-HODE [13(R,S)-hydroxy-9Z,11E-octadecadienoic acid], while 9- and 13-keto-octadecadienoic acid were formed in trace amounts. However, lipid oxidation by the Y103F variant of Mb proceeded with a lower Vmax value and an increased Km value relative to the wild-type control. Consistent with the increased Km, the product distribution from reactions with Y103F Mb showed decreased selectivity compared with the wild-type protein, as judged by the decreased yield of 9(S)-relative to 9(R)-HODE. Together, these data verify that Tyr103 plays a significant role in substrate binding and orientation in the haem pocket of human Mb. Also, the midpoint potential for the Fe(III)/(II) one-electron reduction was shifted slightly, but significantly, to a higher potential, confirming the importance of Tyr103 to the hydrogen-bonding network involving residues that line the haem crevice of human Mb. PMID:15035657

  16. Improved production of poly(lactic acid)-like polyester based on metabolite analysis to address the rate-limiting step.

    PubMed

    Matsumoto, Ken'ichiro; Tobitani, Kota; Aoki, Shunsuke; Song, Yuyang; Ooi, Toshihiko; Taguchi, Seiichi

    2014-12-01

    The biosynthesis of poly(lactic acid) (PLA)-like polymers, composed of >99 mol% lactate and a trace amount of 3-hydroxybutyrate, in engineered Corynebacterium glutamicum consists of two steps; the generation of the monomer substrate lactyl-coenzyme A (CoA) and the polyhydroxyalkanoate (PHA) synthase-catalyzed polymerization of lactyl-CoA. In order to increase polymer productivity, we explored the rate-limiting step in PLA-like polymer synthesis based on quantitative metabolite analysis using liquid chromatography mass spectroscopy (LC-MS). A significant pool of lactyl-CoA was found during polymer synthesis. This result suggested that the rate-limitation occurred at the polymerization step. Accordingly, the expression level of PHA synthase was increased by means of codon-optimization of the corresponding gene that consequently led to an increase in polymer content by 4.4-fold compared to the control. Notably, the codon-optimization did not significantly affect the concentration of lactyl-CoA, suggesting that the polymerization reaction was still the rate-limiting step upon the overexpression of PHA synthase. Another important finding was that the generation of lactyl-CoA was concomitant with a decrease in the acetyl-CoA level, indicating that acetyl-CoA served as a CoA donor for lactyl-CoA synthesis. These results show that obtaining information on the metabolite concentrations is highly useful for improving PLA-like polymer production. This strategy should be applicable to a wide range of PHA-producing systems. PMID:26267112

  17. Fumaric acid production by fermentation

    PubMed Central

    Roa Engel, Carol A.; Zijlmans, Tiemen W.; van Gulik, Walter M.; van der Wielen, Luuk A. M.

    2008-01-01

    The potential of fumaric acid as a raw material in the polymer industry and the increment of cost of petroleum-based fumaric acid raises interest in fermentation processes for production of this compound from renewable resources. Although the chemical process yields 112% w/w fumaric acid from maleic anhydride and the fermentation process yields only 85% w/w from glucose, the latter raw material is three times cheaper. Besides, the fermentation fixes CO2. Production of fumaric acid by Rhizopus species and the involved metabolic pathways are reviewed. Submerged fermentation systems coupled with product recovery techniques seem to have achieved economically attractive yields and productivities. Future prospects for improvement of fumaric acid production include metabolic engineering approaches to achieve low pH fermentations. PMID:18214471

  18. Microbial production of lactic acid.

    PubMed

    Eiteman, Mark A; Ramalingam, Subramanian

    2015-05-01

    Lactic acid is an important commodity chemical having a wide range of applications. Microbial production effectively competes with chemical synthesis methods because biochemical synthesis permits the generation of either one of the two enantiomers with high optical purity at high yield and titer, a result which is particularly beneficial for the production of poly(lactic acid) polymers having specific properties. The commercial viability of microbial lactic acid production relies on utilization of inexpensive carbon substrates derived from agricultural or waste resources. Therefore, optimal lactic acid formation requires an understanding and engineering of both the competing pathways involved in carbohydrate metabolism, as well as pathways leading to potential by-products which both affect product yield. Recent research leverages those biochemical pathways, while researchers also continue to seek strains with improved tolerance and ability to perform under desirable industrial conditions, for example, of pH and temperature. PMID:25604523

  19. Biotechnological production of citric acid

    PubMed Central

    Max, Belén; Salgado, José Manuel; Rodríguez, Noelia; Cortés, Sandra; Converti, Attilio; Domínguez, José Manuel

    2010-01-01

    This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid. PMID:24031566

  20. PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS

    DOEpatents

    Haworth, W.N.; Stacey, M.

    1949-08-30

    A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

  1. NPP ATMS Snowfall Rate Product

    NASA Technical Reports Server (NTRS)

    Meng, Huan; Ferraro, Ralph; Kongoli, Cezar; Wang, Nai-Yu; Dong, Jun; Zavodsky, Bradley; Yan, Banghua

    2015-01-01

    Passive microwave measurements at certain high frequencies are sensitive to the scattering effect of snow particles and can be utilized to retrieve snowfall properties. Some of the microwave sensors with snowfall sensitive channels are Advanced Microwave Sounding Unit (AMSU), Microwave Humidity Sounder (MHS) and Advance Technology Microwave Sounder (ATMS). ATMS is the follow-on sensor to AMSU and MHS. Currently, an AMSU and MHS based land snowfall rate (SFR) product is running operationally at NOAA/NESDIS. Based on the AMSU/MHS SFR, an ATMS SFR algorithm has been developed recently. The algorithm performs retrieval in three steps: snowfall detection, retrieval of cloud properties, and estimation of snow particle terminal velocity and snowfall rate. The snowfall detection component utilizes principal component analysis and a logistic regression model. The model employs a combination of temperature and water vapor sounding channels to detect the scattering signal from falling snow and derive the probability of snowfall (Kongoli et al., 2015). In addition, a set of NWP model based filters is also employed to improve the accuracy of snowfall detection. Cloud properties are retrieved using an inversion method with an iteration algorithm and a two-stream radiative transfer model (Yan et al., 2008). A method developed by Heymsfield and Westbrook (2010) is adopted to calculate snow particle terminal velocity. Finally, snowfall rate is computed by numerically solving a complex integral. NCEP CMORPH analysis has shown that integration of ATMS SFR has improved the performance of CMORPH-Snow. The ATMS SFR product is also being assessed at several NWS Weather Forecast Offices for its usefulness in weather forecast.

  2. Amino acids in sheep production.

    PubMed

    McCoard, Susan A; Sales, Francisco A; Sciascia, Quentin L

    2016-01-01

    Increasing production efficiency with a high standard of animal welfare and respect for the environment is a goal of sheep farming systems. Substantial gains in productivity have been achieved through improved genetics, nutrition and management changes; however the survival and growth performance of multiple-born lambs still remains a problem. This is a significant production efficiency and animal well-being issue. There is a growing body of evidence that some amino acids have a role in regulating growth, reproduction and immunity through modulation of metabolic and cell signaling pathways. The purpose of this review is to provide an overview of what is currently known about the role of amino acids in sheep production and the potential for supplementation strategies to influence on-farm survival and growth of lambs. PMID:26709661

  3. Degradation rates of glycerol polyesters at acidic and basic conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyesters prepared from glycerol with mixtures of adipic and citric acids were evaluated in the laboratory to estimate degradation rates over a range of pH conditions. These renewable polymers provide a market for glycerol that is generated during biodiesel production. The polyesters were prepared...

  4. Radiolytic hydrogen production from process vessels in HB line - production rates compared to evolution rates and discussion of LASL reviews

    SciTech Connect

    Bibler, N.E.

    1992-11-12

    Hydrogen production from radiolysis of aqueous solutions can create a safety hazard since hydrogen is flammable. At times this production can be significant, especially in HB line where nitric acid solutions containing high concentrations of Pu-238, an intense alpha emitter, are processed. The hydrogen production rates from these solutions are necessary for safety analyses of these process systems. The methods and conclusions of hydrogen production rate tests are provided in this report.

  5. Modeling the continuous lactic acid production process from wheat flour.

    PubMed

    Gonzalez, Karen; Tebbani, Sihem; Lopes, Filipa; Thorigné, Aurore; Givry, Sébastien; Dumur, Didier; Pareau, Dominique

    2016-01-01

    A kinetic model of the simultaneous saccharification, protein hydrolysis, and fermentation (SSPHF) process for lactic acid production from wheat flour has been developed. The model describes the bacterial growth, substrate consumption, lactic acid production, and maltose hydrolysis. The model was fitted and validated with data from SSPHF experiments obtained under different dilution rates. The results of the model are in good agreement with the experimental data. Steady state concentrations of biomass, lactic acid, glucose, and maltose as function of the dilution rate were predicted by the model. This steady state analysis is further useful to determine the operating conditions that maximize lactic acid productivity. PMID:26399412

  6. Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, α-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

  7. 30 CFR 250.1632 - Production rates.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Production rates. 250.1632 Section 250.1632 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE... § 250.1632 Production rates. Each sulphur deposit shall be produced at rates that will provide...

  8. 30 CFR 250.1632 - Production rates.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Production rates. 250.1632 Section 250.1632 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Sulphur Operations § 250.1632 Production rates. Each...

  9. Production of carboxylic acid and salt co-products

    DOEpatents

    Hanchar, Robert J.; Kleff, Susanne; Guettler, Michael V.

    2014-09-09

    This invention provide processes for producing carboxylic acid product, along with useful salts. The carboxylic acid product that is produced according to this invention is preferably a C.sub.2-C.sub.12 carboxylic acid. Among the salts produced in the process of the invention are ammonium salts.

  10. Toward biotechnological production of adipic acid and precursors from biorenewables.

    PubMed

    Polen, Tino; Spelberg, Markus; Bott, Michael

    2013-08-20

    Adipic acid is the most important commercial aliphatic dicarboxylic acid in the chemical industry and is primarily used for the production of nylon-6,6 polyamide. The current adipic acid market volume is about 2.6 million tons/y and the average annual demand growth rate forecast to stay at 3-3.5% worldwide. Hitherto, the industrial production of adipic acid is carried out by petroleum-based chemo-catalytic processes from non-renewable fossil fuels. However, in the past years, efforts were made to find alternative routes for adipic acid production from renewable carbon sources by biotechnological processes. Here we review the approaches and the progress made toward bio-based production of adipic acid. PMID:22824738

  11. Calcite crystal growth rate inhibition by polycarboxylic acids

    USGS Publications Warehouse

    Reddy, M.M.; Hoch, A.R.

    2001-01-01

    Calcite crystal growth rates measured in the presence of several polycarboxyclic acids show that tetrahydrofurantetracarboxylic acid (THFTCA) and cyclopentanetetracarboxylic acid (CPTCA) are effective growth rate inhibitors at low solution concentrations (0.01 to 1 mg/L). In contrast, linear polycarbocylic acids (citric acid and tricarballylic acid) had no inhibiting effect on calcite growth rates at concentrations up to 10 mg/L. Calcite crystal growth rate inhibition by cyclic polycarboxyclic acids appears to involve blockage of crystal growth sites on the mineral surface by several carboxylate groups. Growth morphology varied for growth in the absence and in the presence of both THFTCA and CPTCA. More effective growth rate reduction by CPTCA relative to THFTCA suggests that inhibitor carboxylate stereochemical orientation controls calcite surface interaction with carboxylate inhibitors. ?? 20O1 Academic Press.

  12. Oxygen transfer rate and sophorose lipid production by Candida bombicola.

    PubMed

    Guilmanov, Vladimir; Ballistreri, Alberto; Impallomeni, Giuseppe; Gross, Richard A

    2002-03-01

    Sophorose lipids (SLs) have applications as surfactants and are produced at high levels by several yeasts. We developed a fed-batch shake-flask method for the production of SLs by Candida bombicola ATCC 22214. Optimal aeration, expressed in terms of oxygen transfer rate, was between 50 and 80 mM O(2)/L h(-1) and resulted in maximum values for both volumetric product formation (1-1.5 g/L h(-1)) and SL yield (350 g/L). The lowest aeration levels resulted in the enrichment in saturated fatty acid SLs at the expense of unsaturated fatty acid SLs. PMID:11788948

  13. Effect of seeding rate on organic production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased demand for organic rice (Oryza sativa L.) has incentivized producer conversion from conventional to organically-managed rice production in the U.S. Little is known on the impacts of seeding rate on organic rice production. A completely randomized factorial design with four replications was...

  14. Cultivation characteristics of immobilized Aspergillus oryzae for kojic acid production.

    PubMed

    Kwak, M Y; Rhee, J S

    1992-04-15

    Aspergillus oryzae in situ grown from spores entrapped in calcium alginate gel beads was used for the production of kojic acid. The immobilized cells in flask cultures produced kojic acid in a linear proportion while maintaining the stable metabolic activity for a prolonged production period. Kojic acid was accumulated up to a high concentration of 83 g/L, at which the kojic acid began to crystallize, and, thus, the culture had to be replaced with fresh media for the next batch culture. The overall productivities of two consecutive cultivations were higher than that of free mycelial fermentation. However, the production rate of kojic acid by the immobilized cells was suddenly decreased with the appearance of central cavernae inside the immobilized gel beads after 12 days of the third batch cultivation. PMID:18601027

  15. Reduction Rates for Higher Americium Oxidation States in Nitric Acid

    SciTech Connect

    Grimes, Travis Shane; Mincher, Bruce Jay; Schmitt, Nicholas C

    2015-09-30

    The stability of hexavalent americium was measured using multiple americium concentrations and nitric acid concentrations after contact with the strong oxidant sodium bismuthate. Contrary to our hypotheses Am(VI) was not reduced faster at higher americium concentrations, and the reduction was only zero-order at short time scales. Attempts to model the reduction kinetics using zero order kinetic models showed Am(VI) reduction in nitric acid is more complex than the autoreduction processes reported by others in perchloric acid. The classical zero-order reduction of Am(VI) was found here only for short times on the order of a few hours. We did show that the rate of Am(V) production was less than the rate of Am(VI) reduction, indicating that some Am(VI) undergoes two electron-reduction to Am(IV). We also monitored the Am(VI) reduction in contact with the organic diluent dodecane. A direct comparison of these results with those in the absence of the organic diluent showed the reduction rates for Am(VI) were not statistically different for both systems. Additional americium oxidations conducted in the presence of Ce(IV)/Ce(III) ions showed that Am(VI) is reduced without the typical growth of Am(V) observed in the systems sans Ce ion. This was an interesting result which suggests a potential new reduction/oxidation pathway for Am in the presence of Ce; however, these results were very preliminary, and will require additional experiments to understand the mechanism by which this occurs. Overall, these studies have shown that hexavalent americium is fundamentally stable enough in nitric acid to run a separations process. However, the complicated nature of the reduction pathways based on the system components is far from being rigorously understood.

  16. Rate of nova production in the Galaxy

    SciTech Connect

    Liller, W.; Mayer, B.

    1987-07-01

    The ongoing PROBLICOM program in the Southern Hemisphere now makes it possible to derive a reliable value for the overall production rate of Galactic novae. The results, 73 + or - 24/y, indicates that the Galaxy outproduces M 31 by a factor of two or three. It is estimated that the rate of supernova ejecta is one and a half orders of magnitude greater than that of novae in the Galaxy. 15 references.

  17. Comparison of calculations of fragment production rates

    SciTech Connect

    Canavan, G.H.

    1997-08-01

    Differences between NASA and DoD estimates of fragment production rates in space debris collisions are shown to be due primarily to different choices of the exponent in the debris distribution. The sensitivity to this parameter over the range of values consistent with experimental data is discussed.

  18. Biochemistry of microbial itaconic acid production

    PubMed Central

    Steiger, Matthias G.; Blumhoff, Marzena L.; Mattanovich, Diethard; Sauer, Michael

    2013-01-01

    Itaconic acid is an unsaturated dicarbonic acid which has a high potential as a biochemical building block, because it can be used as a monomer for the production of a plethora of products including resins, plastics, paints, and synthetic fibers. Some Aspergillus species, like A. itaconicus and A. terreus, show the ability to synthesize this organic acid and A. terreus can secrete significant amounts to the media (>80 g/L). However, compared with the citric acid production process (titers >200 g/L) the achieved titers are still low and the overall process is expensive because purified substrates are required for optimal productivity. Itaconate is formed by the enzymatic activity of a cis-aconitate decarboxylase (CadA) encoded by the cadA gene in A. terreus. Cloning of the cadA gene into the citric acid producing fungus A. niger showed that it is possible to produce itaconic acid also in a different host organism. This review will describe the current status and recent advances in the understanding of the molecular processes leading to the biotechnological production of itaconic acid. PMID:23420787

  19. Organic Acid Production by Filamentous Fungi

    SciTech Connect

    Magnuson, Jon K.; Lasure, Linda L.

    2004-05-03

    Many of the commercial production processes for organic acids are excellent examples of fungal biotechnology. However, unlike penicillin, the organic acids have had a less visible impact on human well-being. Indeed, organic acid fermentations are often not even identified as fungal bioprocesses, having been overshadowed by the successful deployment of the β-lactam processes. Yet, in terms of productivity, fungal organic acid processes may be the best examples of all. For example, commercial processes using Aspergillus niger in aerated stirred-tank-reactors can convert glucose to citric acid with greater than 80% efficiency and at final concentrations in hundreds of grams per liter. Surprisingly, this phenomenal productivity has been the object of relatively few research programs. Perhaps a greater understanding of this extraordinary capacity of filamentous fungi to produce organic acids in high concentrations will allow greater exploitation of these organisms via application of new knowledge in this era of genomics-based biotechnology. In this chapter, we will explore the biochemistry and modern genetic aspects of the current and potential commercial processes for making organic acids. The organisms involved, with a few exceptions, are filamentous fungi, and this review is limited to that group. Although yeasts including Saccharomyces cerevisiae, species of Rhodotorula, Pichia, and Hansenula are important organisms in fungal biotechnology, they have not been significant for commercial organic acid production, with one exception. The yeast, Yarrowia lipolytica, and related yeast species, may be in use commercially to produce citric acid (Lopez-Garcia, 2002). Furthermore, in the near future engineered yeasts may provide new commercial processes to make lactic acid (Porro, Bianchi, Ranzi, Frontali, Vai, Winkler, & Alberghina, 2002). This chapter is divided into two parts. The first contains a review of the commercial aspects of current and potential large

  20. Modeling of asteroidal dust production rates

    NASA Technical Reports Server (NTRS)

    Durda, Daniel D.; Dermott, Stanley F.; Gustafson, Bo A. S.

    1992-01-01

    The production rate of dust associated with the prominent Hirayama asteroid families and the background asteroidal population are modeled with the intent of using the families as a calibrator of mainbelt dust production. However, the dust production rates of asteroid families may be highly stochastic; there is probably more than an order of magnitude variation in the total area of dust associated with a family. Over 4.5 x 10(exp 9) years of collisional evolution, the volume (mass) of a family is ground down by an order of magnitude, suggesting a similar loss from the entire mainbelt population. Our collisional models show that the number of meteoroids deliverable to Earth also varies stochastically, but only by a factor of 2 to 3.

  1. [Ni(PPh2NC6H4X2)2]2+ Complexes as Electrocatalysts for H2 Production: Effect of Substituents, Acids, and Water on Catalytic Rates

    SciTech Connect

    Kilgore, Uriah J.; Roberts, John A.; Pool, Douglas H.; Appel, Aaron M.; Stewart, Michael P.; Rakowski DuBois, Mary; Dougherty, William G.; Kassel, W. S.; Bullock, R. Morris; DuBois, Daniel L.

    2011-04-20

    A series of mononuclear nickel(II) bis(diphosphine) complexes [Ni(PPh2NPhX2)2](BF4)2 (PPh2NPhX2 = 1,5-di(para¬-X-phenyl)-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane; X = OMe, Me, CH2P(O)(OEt)2, Br, and CF3) have been synthesized and characterized. X-ray diffraction studies reveal that [Ni(PPh2NPhMe2)2](BF4)2 and [Ni(PPh2NPhOMe2)2](BF4)2 are tetracoordinate with distorted square planar geometries. The Ni(II/I) and Ni(I/0) redox couples of each complex are electrochemically reversible in acetonitrile (0.2 M tetraethylammonium tetrafluoroborate) with potentials that are increasingly cathodic as the electron-donating character of X is increased. All of these complexes are efficient electrocatalysts for hydrogen production, with rates generally increasing as the electron-donating character of X is decreased. Catalytic studies using 2,6-dichloroanilinium triflate (2,6-Cl2AnH+OTf , pKaMeCN = 5.0) 4-cyanoanilinium tetrafluoroborate (4-CNAnH+OTf , pKaMeCN = 7.0) and protonated dimethylformamide ([(DMF)H]+OTf , pKaMeCN = 6.1) reveal that turnover frequencies do not correlate with substrate acid pKa values, but are highly dependent on the acid structure, with this effect being related to substrate size. Addition of water is shown to dramatically increase catalytic rates for all catalysts. With [Ni(PPh2NPhCH2P(O)(OEt)22)2](BF4)2 using [(DMF)H]+OTf as acid and with added water, a turnover frequency of 1850 s-1 was obtained. This work was supported by the US Department of Energy Basic Energy Sciences' Chemical Sciences, Geosciences & Biosciences Division. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  2. Photochemical Production Rates in Western Houston

    SciTech Connect

    Berkowitz, Carl M.; Spicer, C. W.; Doskey, Paul V.

    2004-01-01

    In this paper, we evaluate the instantaneous O3 chemical production rates, NOx (= NO + NO2) loss rates and ozone production efficiency within ozone plumes sampled on the west side of Houston, Texas, during the Texas 2000 Air Quality Study. We emphasize days during which rapid increases associated with plume passage were observed in the 15-minute average ozone mixing ratio, O3. The basis for this work will be observations of key nitrogen species and VOCs collected from the top of a sky scraper on the western edge of the city. These observations are used in a 0-dimensional model to quantify the chemical kinetics within parcels of air associated with ozone levels in excess of 100 ppb. We identify the key VOCs affecting ozone production and assess the relative role of anthropogenic versus biogenic VOCs to local ozone production. We also examine how the daily variations in ozone production and ozone production efficiencies are related to differences in VOC/NOx ratios.

  3. Production of Succinic Acid for Lignocellulosic Hydrolysates

    SciTech Connect

    Davison, B.H.; Nghiem, J.

    2002-06-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) is to add and test new metabolic activities to existing microbial catalysts for the production of succinic acid from renewables. In particular, they seek to add to the existing organism the ability to utilize xylose efficiently and simultaneously with glucose in mixtures of sugars or to add succinic acid production to another strain and to test the value of this new capability for production of succinic acid from industrial lignocellulosic hydrolyasates. The Contractors and Participant are hereinafter jointly referred to as the 'Parties'. Research to date in succinic acid fermentation, separation and genetic engineering has resulted in a potentially economical process based on the use of an Escherichia coli strain AFP111 with suitable characteristics for the production of succinic acid from glucose. Economic analysis has shown that higher value commodity chemicals can be economically produced from succinic acid based on repliminary laboratory findings and predicted catalytic parameters. The initial target markets include succinic acid itself, succinate salts, esters and other derivatives for use as deicers, solvents and acidulants. The other commodity products from the succinic acid platform include 1,4-butanediol, {gamma}-butyrolactone, 2-pyrrolidinone and N-methyl pyrrolidinone. Current economic analyses indicate that this platform is competitive with existing petrochemical routes, especially for the succinic acid and derivatives. The report presents the planned CRADA objectives followed by the results. The results section has a combined biocatalysis and fermentation section and a commercialization section. This is a nonproprietary report; additional proprietary information may be made available subject to acceptance of the appropriate proprietary information agreements.

  4. Towards a Model for Protein Production Rates

    NASA Astrophysics Data System (ADS)

    Dong, J. J.; Schmittmann, B.; Zia, R. K. P.

    2007-07-01

    In the process of translation, ribosomes read the genetic code on an mRNA and assemble the corresponding polypeptide chain. The ribosomes perform discrete directed motion which is well modeled by a totally asymmetric simple exclusion process (TASEP) with open boundaries. Using Monte Carlo simulations and a simple mean-field theory, we discuss the effect of one or two "bottlenecks" (i.e., slow codons) on the production rate of the final protein. Confirming and extending previous work by Chou and Lakatos, we find that the location and spacing of the slow codons can affect the production rate quite dramatically. In particular, we observe a novel "edge" effect, i.e., an interaction of a single slow codon with the system boundary. We focus in detail on ribosome density profiles and provide a simple explanation for the length scale which controls the range of these interactions.

  5. ESTIMATION OF CARBOXYLIC ACID ESTER HYDROLYSIS RATE CONSTANTS

    EPA Science Inventory

    SPARC chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid esters from molecular structure. The energy differences between the initial state and the transition state for a molecule of interest are factored into internal and external...

  6. Heart Rate Response and Lactic Acid Concentration in Squash Players.

    ERIC Educational Resources Information Center

    Beaudin, Paula; And Others

    1978-01-01

    It was concluded that playing squash is an activity that results in heart rate responses of sufficient intensity to elicit aerobic training effects without producing high lactic acid concentration in the blood. (MM)

  7. A Comparative Overview of Prescription Omega-3 Fatty Acid Products

    PubMed Central

    Ito, Matthew K.

    2015-01-01

    An estimated 25% of adults in the United States have elevated triglyceride (TG) levels. This is of particular concern given the evidence for a causal role of TG in the pathway of cardiovascular (CV) disease. Approved prescription omega-3 fatty acid products (RxOM3FAs) contain the long-chain fatty acids docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA) and are effective options for the treatment of high TG levels. RxOM3FAs that contain both EPA and DHA include omega-3-acid ethyl esters (ethyl esters of EPA and DHA; brand and generic products) and omega-3-carboxylic acids (free fatty acids primarily composed of EPA and DHA), while the RxOM3FA icosapent ethyl (the ethyl ester of EPA) contains EPA only. All RxOM3FA products produce substantial TG reduction and other beneficial effects on atherogenic lipid and inflammation-related parameters, blood pressure, and heart rate variability, but products that contain DHA may raise low-density lipoprotein-cholesterol (LDL-C). This commentary provides an overview of hypertriglyceridemia while summarizing the pharmacology, efficacy, and safety of prescription RxOM3FAs. PMID:26681905

  8. Increased fracture penetration and productivity using xanthan gelled acid in massive carbonate formations

    SciTech Connect

    Molon, J.P.; Fox, K.B.

    1983-03-01

    A measurable improvement in productivity can be achieved using xanthan gelled acid to stimulate carbonate formations. Well productivity results were compared to conventional acid fracture treatments. The significant improvements over classical acid fracturing techniques are due to the improved control of acid leakoff rates, retarded reaction rate and improved fracture width maintenance. The difficulties involved in acid fracturing massive Middle East carbonate formations are discussed and solutions are proposed using gelled acid technology. Some limitations in computer predictions of acid fracturing results are also discussed.

  9. Production of Gluconic Acid by Some Local Fungi

    PubMed Central

    Shindia, A. A.; El-Esawy, A. E.; Sheriff, Y. M. M. M.

    2006-01-01

    Forty-one fungal species belonging to 15 fungal genera isolated from Egyptian soil and sugar cane waste samples were tested for their capacity of producing acidity and gluconic acid. For the tests, the fungi were grown on glucose substrate and culture filtrates were examined using paper chromatography analysis. Most of the tested fungi have a relative wide potentiality for total acid production in their filtrates. Nearly 51% of them showed their ability of producing gluconic acid. Aspergillus niger was distinguishable from other species by its capacity to produce substantial amounts of gluconic acid when it was cultivated on a selective medium. The optimized cultural conditions for gluconic acid yields were using submerged culture at 30℃ at initial pH 6.0 for 7 days of incubation. Among the various concentrations of substrate used, glucose (14%, w/v) was found to be the most suitable carbon source for maximal gluconic acid during fermentation. Maximum values of fungal biomass (10.02 g/l) and gluconic acid (58.46 g/l) were obtained when the fungus was grown with 1% peptone as sole nitrogen source. Influence of the concentration of some inorganic salts as well as the rate of aeration on the gluconic acid and biomass production is also described. PMID:24039465

  10. Relating Productivity Events to Holocene Bivalve Shell Growth Rates

    NASA Astrophysics Data System (ADS)

    Huntley, J. W.; Krause, R. A.; Kowalewski, M.; Romanek, C. S.; Kaufman, D. S.; Simoes, M. G.

    2007-12-01

    The growth rate of a bivalve can be influenced by many environmental factors that can change during the life of the organism. In this contribution we present initial data from a millennium scale chronology to assess the relationship between ontogenetic growth in the bivalve Semele casali and paleoenvironmental conditions preserved in the shell using growth increment analysis, radiocarbon-calibrated amino acid racemization dating techniques, stable isotopes (C and O) and high spatial resolution (125-150 samples per cm of shell profile) trace element (Ba, Mn) analysis (LA-ICPMS). Time-averaged specimens of S. casali were dredged from two sites at 10 meters and 30 meters depth along the inner continental shelf at Ubatuba Bay in the Southeast Brazilian Bight, an area influenced by productivity pulses triggered by coastal runoff events and coastal upwelling. Seventy-five individual valves were dated using amino acid racemization (aspartic acid). Dates were calculated using an expanded version of a previously published relationship (Barbour Wood et al., 2006 Quaternary Research 323- 331) between aspartic acid ratios and AMS radiocarbon dates of twelve S. casali individuals from the same sampling locations. The resulting time series has complete coverage for the past three thousand years at centennial resolution. From this time series, a sub-sample of dated valves was selected for more detailed growth increment, stable isotope and high-resolution trace element (Ba/Ca and Mn/Ca) analyses. Oceanic productivity is expressed differentially in the trace element profiles of S. casali with elevated Ba/Ca and Mn/Ca ratios capturing nutrient input through coastal runoff events while elevated Ba/Ca and depressed Mn/Ca ratios represent input through coastal upwelling. Fluctuations in Ba/Ca and Mn/Ca are not correlated to fluctuations in relative growth throughout the ontogeny of an individual bivalve, nor are they expected to be as periods of increased productivity are transient

  11. Unusal pattern of product inhibition: batch acetic acid fermentation

    SciTech Connect

    Bar, R.; Gainer, J.L.; Kirwan, D.J.

    1987-04-20

    The limited tolerance of microorganisms to their metabolic products results in inhibited growth and product formation. The relationship between the specific growth rate, micro, and the concentration of an inhibitory product has been described by a number of mathematical models. In most cases, micro was found to be inversely proportional to the product concentration and invariably the rate of substrate utilization followed the same pattern. In this communication, the authors report a rather unusual case in which the formation rate of a product, acetic acid, increased with a decreasing growth rate of the microorganism, Acetobacter aceti. Apparently, a similar behavior was mentioned in a review report with respect to Clostridium thermocellum in a batch culture but was not published in the freely circulating literature. The fermentation of ethanol to acetic acid, C/sub 2/H/sub 5/OH + O/sub 2/ = CH/sub 3/COOH + H/sub 2/O is clearly one of the oldest known fermentations. Because of its association with the commercial production of vinegar it has been a subject of extensive but rather technically oriented studies. Suprisingly, the uncommon uncoupling between the inhibited microbial growth and the product formation appears to have been unnoticed. 13 references.

  12. Economic aspects of amino acids production.

    PubMed

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  13. ATMS Snowfall Rate Product and Its Applications

    NASA Astrophysics Data System (ADS)

    Meng, H.; Kongoli, C.; Dong, J.; Wang, N. Y.; Ferraro, R. R.; Zavodsky, B.; Banghua Yan, B.

    2015-12-01

    A snowfall rate (SFR) algorithm has been developed for the Advanced Technology Microwave Sounder (ATMS) aboard S-NPP and future JPSS satellites. The product is based on the NOAA/NESDIS operational Microwave Humidity Sounder (MHS) SFR but with several key advancements. The algorithm has benefited from continuous development to improve accuracy and snowfall detection efficiency. The enhancements also expand the applicable temperature range for the algorithm and allow significantly more snowfall to be detected than the operational SFR. Another major improvement is the drastically reduced product latency by using Direct Broadcast (DB) data. The new developments have also been implemented in the MHS SFR to ensure product consistency across satellites. Currently, there are five satellites that carry either ATMS or MHS: S-NPP, NOAA-18/-19 and Metop-A/-B. The combined satellites deliver up to ten SFR estimates a day at any location over land in mid-latitudes. The product provides much needed winter precipitation estimates for applications such as weather forecasting and hydrology. Both ATMS and MHS SFR serve as input to a global precipitation analysis product, the NOAA/NCEP CMORPH-Snow. SFR is the sole satellite-based snowfall estimates in the blended product. In addition, ATMS and MHS SFR was assessed at several NWS Weather Forecast Offices (WFOs) and NESDIS/Satellite Analysis Branch (SAB) for its operational values in winter 2015. This is a joint effort among NASA/SPoRT, NOAA/NESDIS, University of Maryland/CICS, and the WFOs. The feedback from the assessment indicated that SFR provides useful information for snowfall forecast. It is especially valuable for areas with poor radar coverage and ground observations. The feedback also identified some limitations of the product such as inadequate detection of shallow snowfall. The algorithm developers will continue to improve product quality as well as developing SFR for new microwave sensors and over ocean in a project

  14. Fatty acid production in genetically modified cyanobacteria

    PubMed Central

    Liu, Xinyao; Sheng, Jie; Curtiss III, Roy

    2011-01-01

    To avoid costly biomass recovery in photosynthetic microbial biofuel production, we genetically modified cyanobacteria to produce and secrete fatty acids. Starting with introducing an acyl–acyl carrier protein thioesterase gene, we made six successive generations of genetic modifications of cyanobacterium Synechocystis sp. PCC6803 wild type (SD100). The fatty acid secretion yield was increased to 197 ± 14 mg/L of culture in one improved strain at a cell density of 1.0 × 109 cells/mL by adding codon-optimized thioesterase genes and weakening polar cell wall layers. Although these strains exhibited damaged cell membranes at low cell densities, they grew more rapidly at high cell densities in late exponential and stationary phase and exhibited less cell damage than cells in wild-type cultures. Our results suggest that fatty acid secreting cyanobacteria are a promising technology for renewable biofuel production. PMID:21482809

  15. Biotechnological production and application of ganoderic acids.

    PubMed

    Xu, Jun-Wei; Zhao, Wei; Zhong, Jian-Jiang

    2010-06-01

    Ganoderic acids (GAs), a kind of highly oxygenated lanostane-type triterpenoids, are important bioactive constituents of the famous medicinal mushroom Ganoderma lucidum. They have received wide attention in recent years due to extraordinarily pharmacological functions. Submerged fermentation of G. lucidum is viewed as a promising technology for production of GAs, and substantial efforts have been devoted to process development for enhancing GA production in the last decade. This article reviews recent publication about fermentative production of GAs and their potential applications, especially the progresses toward manipulation of fermentation conditions and bioprocessing strategies are summarized. The biosynthetic pathway of GAs is also outlined. PMID:20437236

  16. Production Rate of Cosmogenic 10Be in Magnetite

    NASA Astrophysics Data System (ADS)

    Granger, D. E.; Rogers, H. E.; Riebe, C. S.; Lifton, N. A.

    2013-12-01

    Cosmogenic 10Be is widely used for determining exposure ages, soil production rates, and catchment-wide erosion rates. To date, measurements have been almost exclusively in the mineral quartz (SiO2), which is resistant to weathering and easily cleaned of meteoric 10Be contamination. However, this limits the method to quartz-bearing rocks and requires specialized laboratories due to the need for large quantities of hydrofluoric acid (HF). Here, we present initial results for 10Be production in the mineral magnetite (Fe3O4). Magnetite offers several advantages over quartz; it is (1) present in mafic rocks, (2) easily collected in the field, (3) quickly and easily separated in the lab, and (4) digested without HF. In addition, 10Be can be measured in both detrital quartz and magnetite from the same catchment to yield information about the intensity of chemical weathering (Rogers et al., this conference). The 10Be production rate in magnetite relative to quartz was determined for a granitic boulder from Mt. Evans, Colorado, USA. The boulder was crushed and homogenized to facilitate production rate comparisons among various minerals. We separated magnetite using a combination of hand magnets, froth flotation, and a variety of selective chemical dissolutions in dithionite-citrate-bicarbonate solution, 5% nitric acid (HNO3) and 1% HF/HNO3. Six aliquots of magnetite were analyzed for 10Be and compared to quartz. Three aliquots that were not exposed to 1% HF/HNO3 were contaminated with meteoric 10Be, probably associated with residual mica. Three aliquots that were exposed to 1% HF/HNO3 treatments agreed to within 2% measurement uncertainty. Our preliminary results indicate that the relative production rate by mass of 10Be in magnetite and quartz is 0.462 × 0.012. Our results are similar to theoretically predicted values. Recently updated excitation functions for neutron and proton spallation reactions allow us to partition 10Be production in quartz and magnetite among

  17. Production of fusaric acid by Fusarium species.

    PubMed Central

    Bacon, C W; Porter, J K; Norred, W P; Leslie, J F

    1996-01-01

    Fusaric acid is a mycotoxin with low to moderate toxicity, which is of concern since it might be synergistic with other cooccurring mycotoxins. Fusaric acid is widespread on corn and corn-based food and feeds and is frequently found in grain, where Fusarium spp. are also isolated. We surveyed 78 strains of Fusarium moniliforme, F. crookwellense, F. subglutinans, F. sambucinum, F. napiforme, F. heterosporum, F. oxysporum, F. solani, and F. proliferatum for their ability to produce fusaric acid. Strains in Fusarium section Liseola also were assigned to mating population of the Gibberella fujikuroi species complex. The fungi could be divided into three classes, low (< 100 micrograms/g), moderate (100 to 500 micrograms/g), and high (> 500 micrograms/g), based on the amounts of this mycotoxin produced in culture on autoclaved corn. Strains of mating populations C from rice consistently produced moderate to high concentrations of fusaric acid. Two isolates, one each from mating populations C and D, produced fusaric acid in excess of 1,000 micrograms/g of corn. No isolates of any of the Fusarium species examined were negative for the production of fusaric acid on autoclaved corn. PMID:8899996

  18. Photosynthetic production of itaconic acid in Synechocystis sp. PCC6803.

    PubMed

    Chin, Taejun; Sano, Mei; Takahashi, Tetsuya; Ohara, Hitomi; Aso, Yuji

    2015-02-10

    Here, we report the photosynthetic production of itaconic acid (IA), a promising building block, from carbon dioxide (CO₂) by Synechocystis sp. PCC6803. The engineered PCC6803 strain expressing cis-aconitate decarboxylase, the key enzyme in IA biosynthesis, produced 0.9 mg/L and 14.5 mg/L of IA at production rates of 42.8 μgL(-1)day(-1) and 919.0 μgL(-1)day(-1), under conditions of constant bubbling with air and 5% CO₂, respectively. This is the first report on the possibility of IA production from CO₂ via the photosynthetic process in cyanobacteria. PMID:25554635

  19. Extraction chemistry of fermentation product carboxylic acids

    SciTech Connect

    Kertes, A.S.; King, C.J.

    1986-02-01

    Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathways and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase.

  20. Extraction chemistry of fermentation product carboxylic acid

    SciTech Connect

    Kertes, A.S.; King, C.J.

    1986-02-01

    Within the framework of a program aiming to improve the existing extractive recovery technology of fermentation products, the state of the art is critically reviewed. The acids under consideration are propionic, lactic, pyruvic, succinic, fumaric, maleic, malic, itaconic, tartaric, citric, and isocitric, all obtained by the aerobic fermentation of glucose via the glycolytic pathway and glyoxylate bypass. With no exception, it is the undissociated monomeric acid that is extracted into carbon-bonded and phosphorus-bonded oxygen donor extractants. In the organic phase, the acids are usually dimerized. The extractive transfer process obeys the Nernst law, and the measured partition coefficients range from about 0.003 for aliphatic hydrocarbons to about 2 to 3 for aliphatic alcohols and ketones to about 10 or more for organophosphates. Equally high distribution ratios are measured when long-chain tertiary amines are employed as extractants, forming bulky salts preferentially soluble in the organic phase. 123 references.

  1. Association between the proportion of sampled transition cows with increased nonesterified fatty acids and beta-hydroxybutyrate and disease incidence, pregnancy rate, and milk production at the herd level.

    PubMed

    Ospina, P A; Nydam, D V; Stokol, T; Overton, T R

    2010-08-01

    In this study the herd alarm level was defined as the proportion of sampled transition cows per herd with increased prepartum nonesterified fatty acid (NEFA), postpartum beta-hydroxybutyrate (BHBA), or NEFA concentrations that were associated with herd-level incidence of displaced abomasum (DA) or clinical ketosis (CK), pregnancy rate (PR), and milk production. The objectives were to 1) identify the herd alarm level for excessive negative energy balance and 2) describe the herd-level prevalence of this proportion. This was a prospective cohort study of 60 free-stall herds fed total mixed rations in the northeast United States. Two cohorts of approximately 15 animals were assessed for prepartum NEFA and postpartum BHBA and NEFA. The herd alarm level (i.e., the proportion of sampled animals above a certain metabolite threshold) was as follows: 15% had prepartum NEFA of 0.27 mEq/L; 15 and 20% had BHBA of 10 and 12 mg/dL, respectively; and 15% had postpartum NEFA of 0.60 and 0.70 mEq/L. The different herd alarm levels correspond to differences between the metabolites and respective herd-level effect. The herd-level effects for herds above the herd alarm level for prepartum NEFA were 3.6% increase in DA and CK incidence, 1.2% decrease in PR, and 282 kg decrease in average mature equivalent 305-d (ME 305) milk. For BHBA, the herd-level effects were a 1.8% increase in DA and CK, 0.8% decrease in PR, and 534 and 358 kg decrease in projected ME 305 milk yield for heifers and cows, respectively. For postpartum NEFA, the herd-level effects were 1.7% increase in DA and CK, 0.9% decrease in PR, and 288 and 593 kg decrease in projected ME 305 milk yield for heifers and cows, respectively. The prevalence of herds in which more than 15% of animals sampled had prepartum NEFA concentration >or=0.30 mEq/L was 75%, BHBA >or=12 mg/dL was 40%, and postpartum NEFA >or=0.70 mEq/L was 65%. This study showed that there were detrimental herd-level effects if a large enough proportion of cows

  2. TREATOGENIC ACTIVITY OF TRICHOLORACETIC ACID IN THE RATE

    EPA Science Inventory

    Trichloroacetic acid (TCA) is a by-product of the chlorine disinfection of water containing natural organic material. t is detectable in finished drinking water at levels comparable to the trihalomethanes (930-160 ug/L). CA is also formed in vivo after ingestion of hypochelorite ...

  3. Production of carboxylates from high rate activated sludge through fermentation.

    PubMed

    Cagnetta, C; Coma, M; Vlaeminck, S E; Rabaey, K

    2016-10-01

    The aim of this work was to study the key parameters affecting fermentation of high rate activated A-sludge to carboxylates, including pH, temperature, inoculum, sludge composition and iron content. The maximum volatile fatty acids production was 141mgCg(-1) VSSfed, at pH 7. Subsequently the potential for carboxylate and methane production for A-sludge from four different plants at pH 7 and 35°C were compared. Initial BOD of the sludge appeared to be key determining carboxylate yield from A-sludge. Whereas methanogenesis could be correlated linearly to the quantity of ferric used for coagulation, fermentation did not show a dependency on iron presence. This difference may enable a strategy whereby A-stage sludge is separated to achieve fermentation, and iron dosing for phosphate removal is only implemented at the B-stage. PMID:27020399

  4. Microbial Products Trigger Amino Acid Exudation from Plant Roots1

    PubMed Central

    Phillips, Donald A.; Fox, Tama C.; King, Maria D.; Bhuvaneswari, T.V.; Teuber, Larry R.

    2004-01-01

    Plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. The dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. We find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 μm) exceed efflux rates by 5% to 545% in roots of alfalfa (Medicago sativa), Medicago truncatula, maize (Zea mays), and wheat (Triticum aestivum). Several microbial products, which are produced by common soil microorganisms such as Pseudomonas bacteria and Fusarium fungi, significantly enhanced the net efflux (i.e. exudation) of amino acids from roots of these four plant species. In alfalfa, treating roots with 200 μm phenazine, 2,4-diacetylphloroglucinol, or zearalenone increased total net efflux of 16 amino acids 200% to 2,600% in 3 h. Data from 15N tests suggest that 2,4-diacetylphloroglucinol blocks amino acid uptake, whereas zearalenone enhances efflux. Thus, amino acid exudation under normal conditions is a phenomenon that probably reflects both active manipulation and passive uptake by microorganisms, as well as diffusion and adsorption to soil, all of which help overcome the innate capacity of plant roots to reabsorb amino acids. The importance of identifying potential enhancers of root exudation lies in understanding that such compounds may represent regulatory linkages between the larger soil food web and the internal carbon metabolism of the plant. PMID:15347793

  5. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    PubMed

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water. PMID:25898079

  6. Support Effects on Bronsted acid site densities and alcohol dehydration turnover rates on tungsten oxide domains

    SciTech Connect

    Macht, Josef; Baertsch, Chelsey D.; May-Lozano, Marcos; Soled, Stuart L.; Wang, Yong; Iglesia, Enrique

    2005-03-01

    Initial activity and acid site density of several WAl, WSi (MCM41) and one WSn sample were determined. Trans/cis 2-butene selectivity is dependent on the support. Presumably, these differences are due to subtle differences in base strengths. 2-Butanol dehydration rates (per W-atom) reached maximum values at intermediate WOx surface densities on WAl, as reported for 2-butanol dehydration reactions on WZr. Titration results indicate that Bronsted acid sites are required for 2-butanol dehydration on WAl, WSi and WSn. UV-visible studies suggest that WAl is much more difficult to reduce than WZr. The detection of reduced centers on WAl, the number of which correlates to Bronsted acid site density and catalyst activity, as well as the temperature dependence of Bronsted acid site density indicate the in-situ formation of these active sites. We infer that this mechanism is common among all supported WOx samples described in this study. Turnover rates are a function of Bronsted acid site density only. High acid site densities lead to high turnover rates. Higher active site densities may cause stronger conjugate bases, as a higher electron density has to be stabilized, and thus weaker acidity, enabling a faster rate of product desorption. The maximum achievable active site density is dependent on the support. WZr reaches a higher active site density than WAl.

  7. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, Nhuan Phu; Donnelly, Mark; Millard, Cynthia S.; Stols, Lucy

    1999-01-01

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; c) controllably releasing oxygen to maintain the aerobic atmosphere; d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/L up to about 1 g/L; e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of .gtoreq.1 g/L; and g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism.

  8. Method for the production of dicarboxylic acids

    DOEpatents

    Nghiem, N.P.; Donnelly, M.; Millard, C.S.; Stols, L.

    1999-02-09

    The present invention is an economical fermentation method for the production of carboxylic acids comprising the steps of (a) inoculating a medium having a carbon source with a carboxylic acid-producing organism; (b) incubating the carboxylic acid-producing organism in an aerobic atmosphere to promote rapid growth of the organism thereby increasing the biomass of the organism; (c) controllably releasing oxygen to maintain the aerobic atmosphere; (d) controllably feeding the organism having increased biomass with a solution containing the carbon source to maintain the concentration of the carbon source within the medium of about 0.5 g/l up to about 1 g/l; (e) depriving the aerobic atmosphere of oxygen to produce an anaerobic atmosphere to cause the organism to undergo anaerobic metabolism; (f) controllably feeding the organism having increased biomass a solution containing the carbon source to maintain the concentration of the carbon source within the medium of {>=}1 g/l; and (g) converting the carbon source to carboxylic acids using the anaerobic metabolism of the organism. 7 figs.

  9. Combinatorial Effects of Fatty Acid Elongase Enzymes on Nervonic Acid Production in Camelina sativa

    PubMed Central

    Huai, Dongxin; Zhang, Yuanyuan; Zhang, Chunyu; Cahoon, Edgar B.; Zhou, Yongming

    2015-01-01

    Very long chain fatty acids (VLCFAs) with chain lengths of 20 carbons and longer provide feedstocks for various applications; therefore, improvement of VLCFA contents in seeds has become an important goal for oilseed enhancement. VLCFA biosynthesis is controlled by a multi-enzyme protein complex referred to as fatty acid elongase, which is composed of β-ketoacyl-CoA synthase (KCS), β-ketoacyl-CoA reductase (KCR), β-hydroxyacyl-CoA dehydratase (HCD) and enoyl reductase (ECR). KCS has been identified as the rate-limiting enzyme, but little is known about the involvement of other three enzymes in VLCFA production. Here, the combinatorial effects of fatty acid elongase enzymes on VLCFA production were assessed by evaluating the changes in nervonic acid content. A KCS gene from Lunaria annua (LaKCS) and the other three elongase genes from Arabidopsis thaliana were used for the assessment. Five seed-specific expressing constructs, including LaKCS alone, LaKCS with AtKCR, LaKCS with AtHCD, LaKCS with AtECR, and LaKCS with AtKCR and AtHCD, were transformed into Camelina sativa. The nervonic acid content in seed oil increased from null in wild type camelina to 6-12% in LaKCS-expressing lines. However, compared with that from the LaKCS-expressing lines, nervonic acid content in mature seeds from the co-expressing lines with one or two extra elongase genes did not show further increases. Nervonic acid content from LaKCS, AtKCR and AtHCD co-expressing line was significantly higher than that in LaKCS-expressing line during early seed development stage, while the ultimate nervonic acid content was not significantly altered. The results from this study thus provide useful information for future engineering of oilseed crops for higher VLCFA production. PMID:26121034

  10. Combinatorial Effects of Fatty Acid Elongase Enzymes on Nervonic Acid Production in Camelina sativa.

    PubMed

    Huai, Dongxin; Zhang, Yuanyuan; Zhang, Chunyu; Cahoon, Edgar B; Zhou, Yongming

    2015-01-01

    Very long chain fatty acids (VLCFAs) with chain lengths of 20 carbons and longer provide feedstocks for various applications; therefore, improvement of VLCFA contents in seeds has become an important goal for oilseed enhancement. VLCFA biosynthesis is controlled by a multi-enzyme protein complex referred to as fatty acid elongase, which is composed of β-ketoacyl-CoA synthase (KCS), β-ketoacyl-CoA reductase (KCR), β-hydroxyacyl-CoA dehydratase (HCD) and enoyl reductase (ECR). KCS has been identified as the rate-limiting enzyme, but little is known about the involvement of other three enzymes in VLCFA production. Here, the combinatorial effects of fatty acid elongase enzymes on VLCFA production were assessed by evaluating the changes in nervonic acid content. A KCS gene from Lunaria annua (LaKCS) and the other three elongase genes from Arabidopsis thaliana were used for the assessment. Five seed-specific expressing constructs, including LaKCS alone, LaKCS with AtKCR, LaKCS with AtHCD, LaKCS with AtECR, and LaKCS with AtKCR and AtHCD, were transformed into Camelina sativa. The nervonic acid content in seed oil increased from null in wild type camelina to 6-12% in LaKCS-expressing lines. However, compared with that from the LaKCS-expressing lines, nervonic acid content in mature seeds from the co-expressing lines with one or two extra elongase genes did not show further increases. Nervonic acid content from LaKCS, AtKCR and AtHCD co-expressing line was significantly higher than that in LaKCS-expressing line during early seed development stage, while the ultimate nervonic acid content was not significantly altered. The results from this study thus provide useful information for future engineering of oilseed crops for higher VLCFA production. PMID:26121034

  11. Effects of hops (Humulus lupulus L.) extract on volatile fatty acid production by rumen bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To determine the effects of hops extract, on in vitro volatile fatty acid (VFA) production by bovine rumen microorganisms. Methods and Results: When mixed rumen microbes were suspended in media containing carbohydrates, the initial rates of VFA production were suppressed by beta-acid rich hops...

  12. Anaerobic microbial dissolution of lead and production of organic acids

    DOEpatents

    Francis, Arokiasamy J.; Dodge, Cleveland; Chendrayan, Krishnachetty; Quinby, Helen L.

    1988-01-01

    The present invention relates to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rate of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 .mu.moles of lead as lead oxide was 0.042 .mu.moles ml.sup.-1 hr.sup.-1. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids.

  13. Photochemical free radical production rates in the eastern Caribbean

    NASA Astrophysics Data System (ADS)

    Dister, Brian; Zafiriou, Oliver C.

    1993-02-01

    Potential photochemical production rates of total (NO-scavengeable) free radicals were surveyed underway (> 900 points) in the eastern Caribbean and Orinoco delta in spring and fall 1988. These data document seasonal trends and large-scale (˜ 10-1000 km) variability in the pools of sunlight-generated reactive transients, which probably mediate a major portion of marine photoredox transformations. Radical production potential was detectable in all waters and was reasonably quantifiable at rates above 0.25 nmol L-1 min-1 sun-1. Radical production rates varied from ˜ 0.1-0.5 nmol L-1 min-1 of full-sun illumination in "blue water" to > 60 nmol L-1 min-1 in some estuarine waters in the high-flow season. Qualitatively, spatiotemporal potential rate distributions strikingly resembled that of "chlorophyll" (a riverine-influence tracer of uncertain specificity) in 1979-1981 CZCS images of the region [Müller-Karger et al., 1988] at all scales. Basin-scale occurrence of greatly enhanced rates in fall compared to spring is attributed to terrestrial chromophore inputs, primarily from the Orinoco River, any contributions from Amazon water and nutrient-stimulus effects could not be resolved. A major part of the functionally photoreactive colored organic matter (COM) involved in radical formation clearly mixes without massive loss out into high-salinity waters, although humic acids may flocculate in estuaries. A similar conclusion applies over smaller scales for COM as measured optically [Blough et al., this issue]. Furthermore, optical absorption and radical production rates were positively correlated in the estuarine region in fall. These cruises demonstrated that photochemical techniques are now adequate to treat terrestrial photochemical chromophore inputs as an estuarine mixing problem on a large scale, though the ancillary data base does not currently support such an analysis in this region. Eastern Caribbean waters are not markedly more reactive at comparable salinities

  14. Metabolic engineering of acid resistance elements to improve acid resistance and propionic acid production of Propionibacterium jensenii.

    PubMed

    Guan, Ningzi; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Chen, Jian; Liu, Long

    2016-06-01

    Propionic acid (PA) and its salts are widely used in the food, pharmaceutical, and chemical industries. Microbial production of PA by propionibacteria is a typical product-inhibited process, and acid resistance is crucial in the improvement of PA titers and productivity. We previously identified two key acid resistance elements-the arginine deaminase and glutamate decarboxylase systems-that protect propionibacteria against PA stress by maintaining intracellular pH homeostasis. In this study, we attempted to improve the acid resistance and PA production of Propionibacterium jensenii ATCC 4868 by engineering these elements. Specifically, five genes (arcA, arcC, gadB, gdh, and ybaS) encoding components of the arginine deaminase and glutamate decarboxylase systems were overexpressed in P. jensenii. The activities of the five enzymes in the engineered strains were 26.7-489.0% higher than those in wild-type P. jensenii. The growth rates of the engineered strains decreased, whereas specific PA production increased significantly compared with those of the wild-type strain. Among the overexpressed genes, gadB (encoding glutamate decarboxylase) increased PA resistance and yield most effectively; the PA resistance of P. jensenii-gadB was more than 10-fold higher than that of the wild-type strain, and the production titer, yield, and conversion ratio of PA reached 10.81 g/L, 5.92 g/g cells, and 0.56 g/g glycerol, representing increases of 22.0%, 23.8%, and 21.7%, respectively. We also investigated the effects of introducing these acid resistance elements on the transcript levels of related enzymes. The results showed that the expression of genes in the engineered pathways affected the expression of the other genes. Additionally, the intracellular pools of amino acids were altered as different genes were overexpressed, which may further contribute to the enhanced PA production. This study provides an effective strategy for improving PA production in propionibacteria; this

  15. The effects of agitation and aeration on the production of gluconic acid by Aspergillus niger

    SciTech Connect

    Dronawat, S.N.; Svihla, C.K.; Hanley, T.R.

    1995-12-31

    The effects of agitation and aeration in the production of gluconic acid by Aspergillus niger from a glucose medium were investigated. Experiments were conducted at aeration rates of 5.0 and 10.0 L/min. Four different agitation speeds were investigated for each aeration rate. Gluconic acid concentration and biomass concentration were analyzed, and the rate of consumption of substrate by A. niger was noted. The main purpose of this work was to find the optimal conditions of agitation and aeration for the growth of A. niger and production of gluconic acid in submerged culture in a batch fermentor at a bench-top scale. The oxygen-transfer rates at different agitation and aeration rates were calculated. The gluconic acid concentration and rate of growth of A. niger increased with increase in the agitation and aeration rates.

  16. Biobased organic acids production by metabolically engineered microorganisms.

    PubMed

    Chen, Yun; Nielsen, Jens

    2016-02-01

    Bio-based production of organic acids via microbial fermentation has been traditionally used in food industry. With the recent desire to develop more sustainable bioprocesses for production of fuels, chemicals and materials, the market for microbial production of organic acids has been further expanded as organic acids constitute a key group among top building block chemicals that can be produced from renewable resources. Here we review the current status for production of citric acid and lactic acid, and we highlight the use of modern metabolic engineering technologies to develop high performance microbes for production of succinic acid and 3-hydroxypropionic acid. Also, the key limitations and challenges in microbial organic acids production are discussed. PMID:26748037

  17. Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants

    DOEpatents

    Ohlrogge, J.B.; Cahoon, E.B.; Shanklin, J.; Somerville, C.R.

    1995-07-04

    The present invention relates to a process for producing lipids containing the fatty acid, petroselinic acid, in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a {omega}12 desaturase from another species which does normally accumulate petroselinic acid. 19 figs.

  18. Method for production of petroselinic acid and OMEGA12 hexadecanoic acid in transgenic plants

    DOEpatents

    Ohlrogge, John B.; Cahoon, Edgar B.; Shanklin, John; Somerville, Christopher R.

    1995-01-01

    The present invention relates to a process for producing lipids containing the fatty acid petroselinic acid in plants. The production of petroselinic acid is accomplished by genetically transforming plants which do not normally accumulate petroselinic acid with a gene for a .omega.12 desaturase from another species which does normally accumulate petroselinic acid.

  19. Substrate inhibition and control for high rate biogas production

    SciTech Connect

    Shin, H.S.

    1982-01-01

    This research addresses a critical aspect of the technical feasibility of biogas recovery with poultry manure using anaerobic digestion, namely, inhibition and toxicity factors limiting methane generation under high rate conditions. The research was designed to identify the limiting factors and to examine alternative pretreatment and in situ control methods for the anaerobic digestion of poultry manure as an energy producing system. Biogas production was indicated by the daily gas volume produced per unit digester capacity. Enhanced biogas generation from the anaerobic digester systems using poultry manure was studied in laboratory- and pilot-scale digester operations. It was found that ammonia nitrogen concentration above 4000 mg/l was inhibitory to biogas production. Pretreatment of the manure by elutriation was effective for decreasing inhibitory/toxic conditions. Increased gas production resulted without an indication of serious inhibition by increased volatile acids, indicating a limitation of available carbon sources. For poultry manure digestion, the optimum pH range was 7.1 to 7.6. Annual costs for pretreatment/biogas systems for 10,000, 30,000 and 50,000 birds were estimated and compared with annual surplus energy produced. The economic break-even point was achieved in digesters for greater than 30,000 birds. Capital cost of the digester system was estimated to be $18,300 with annual costs around $4000. It is anticipated that the digester system could be economically applied to smaller farms as energy costs increase.

  20. The effect of random precipitation times on the scavenging rate for tropospheric nitric acid

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    1988-01-01

    A model for the effective scavenging rate of a soluble species has been developed. The model takes into account the possibility of positive as well as negative correlations between departures from the mean of the scavenging rate and species concentration. The model is demonstrated for the case of late afternoon rainout of nitric acid occurring just prior to the nighttime cessation of its chemical production. The calculations give effective scavenging rates which are about a factor of 2 to 3 greater than those calculated using the models of Rodhe and Grandell (1972) and Giorgi and Chameides (1985).

  1. Recent advances in lactic acid production by microbial fermentation processes.

    PubMed

    Abdel-Rahman, Mohamed Ali; Tashiro, Yukihiro; Sonomoto, Kenji

    2013-11-01

    Fermentative production of optically pure lactic acid has roused interest among researchers in recent years due to its high potential for applications in a wide range of fields. More specifically, the sharp increase in manufacturing of biodegradable polylactic acid (PLA) materials, green alternatives to petroleum-derived plastics, has significantly increased the global interest in lactic acid production. However, higher production costs have hindered the large-scale application of PLA because of the high price of lactic acid. Therefore, reduction of lactic acid production cost through utilization of inexpensive substrates and improvement of lactic acid production and productivity has become an important goal. Various methods have been employed for enhanced lactic acid production, including several bioprocess techniques facilitated by wild-type and/or engineered microbes. In this review, we will discuss lactic acid producers with relation to their fermentation characteristics and metabolism. Inexpensive fermentative substrates, such as dairy products, food and agro-industrial wastes, glycerol, and algal biomass alternatives to costly pure sugars and food crops are introduced. The operational modes and fermentation methods that have been recently reported to improve lactic acid production in terms of concentrations, yields, and productivities are summarized and compared. High cell density fermentation through immobilization and cell-recycling techniques are also addressed. Finally, advances in recovery processes and concluding remarks on the future outlook of lactic acid production are presented. PMID:23624242

  2. Study on the kinetics and transformation products of salicylic acid in water via ozonation.

    PubMed

    Hu, Ruikang; Zhang, Lifeng; Hu, Jiangyong

    2016-06-01

    As salicylic acid is one of widely used pharmaceuticals, its residue has been found in various environmental water systems e.g. wastewater, surface water, treated water and drinking water. It has been reported that salicylic acid can be efficiently removed by advanced oxidation processes, but there are few studies on its transformation products and ozonation mechanisms during ozonation process. The objective of this study is to characterize the transformation products, investigate the degradation mechanisms at different pH, and propose the ozonation pathways of salicylic acid. The results showed that the rate of degradation was about 10 times higher at acidic condition than that at alkaline condition in the first 1 min when 1 mg L(-1) of ozone solution was added into 1 mg L(-1) of salicylic acid solution. It was proposed that ozone direct oxidation mechanism dominates at acidic condition, while indirect OH radical mechanism dominates at alkaline condition. A two stages pseudo-first order reaction was proposed at different pH conditions. Various hydroxylation products, carbonyl compounds and carboxylic acids, such as 2,5-dihydroxylbenzoic acid, 2,3-dihydroxylbenzoic acid, catechol, formaldehyde, glyoxal, acetaldehyde, maleic acid, acetic acid and oxalic acid etc. were identified as ozonation transformation products. In addition, acrylic acid was identified, for the first time, as ozonation transformation products through high resolution liquid chromatography-time of flight mass spectrometer. The information demonstrated in this study will help us to better understand the possible effects of ozonation products on the water quality. The degradation pathways of salicylic acid by ozonation in water sample were proposed. As both O3 and OH radical were important in the reactions, the degradation pathways of salicylic acid by ozonation in water sample were proposed at acidic and basic conditions. To our knowledge, there was no integrated study reported on the ozonation of

  3. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    SciTech Connect

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-10-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site`s Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  4. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    SciTech Connect

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-01-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  5. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    PubMed

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L. PMID:26038800

  6. Aftershock production rate of driven viscoelastic interfaces

    NASA Astrophysics Data System (ADS)

    Jagla, E. A.

    2014-10-01

    We study analytically and by numerical simulations the statistics of the aftershocks generated after large avalanches in models of interface depinning that include viscoelastic relaxation effects. We find in all the analyzed cases that the decay law of aftershocks with time can be understood by considering the typical roughness of the interface and its evolution due to relaxation. In models where there is a single viscoelastic relaxation time there is an exponential decay of the number of aftershocks with time. In models in which viscoelastic relaxation is wave-vector dependent we typically find a power-law dependence of the decay rate that is compatible with the Omori law. The factors that determine the value of the decay exponent are analyzed.

  7. Aftershock production rate of driven viscoelastic interfaces.

    PubMed

    Jagla, E A

    2014-10-01

    We study analytically and by numerical simulations the statistics of the aftershocks generated after large avalanches in models of interface depinning that include viscoelastic relaxation effects. We find in all the analyzed cases that the decay law of aftershocks with time can be understood by considering the typical roughness of the interface and its evolution due to relaxation. In models where there is a single viscoelastic relaxation time there is an exponential decay of the number of aftershocks with time. In models in which viscoelastic relaxation is wave-vector dependent we typically find a power-law dependence of the decay rate that is compatible with the Omori law. The factors that determine the value of the decay exponent are analyzed. PMID:25375460

  8. EFFECTS OF VENTILATION RATES AND PRODUCT LOADING ON ORGANIC EMISSION RATES FROM PARTICLEBOARD

    EPA Science Inventory

    The paper discusses the effects of ventilation rates and product loading on organic emission rates from particleboard. Recently, investigators have confirmed the presence of varied and significant amounts of organic compounds in indoor environment, including compounds known or su...

  9. The Sugar Model: Catalysis by Amines and Amino Acid Products

    NASA Astrophysics Data System (ADS)

    Weber, Arthur L.

    2001-02-01

    Ammonia and amines (including amino acids) were shown to catalyze the formation of sugars from formaldehyde and glycolaldehyde, and the subsequent conversion of sugars to carbonyl-containing products under the conditions studied (pH 5.5 and 50°C). Sterically unhindered primary amines were better catalysts than ammonia, secondary amines, and sterically hindered primary amines (i.e. α-aminoisobutyric acid). Reactions catalyzed by primary amines initially consumed formaldehyde and glycolaldehyde about 15-20 times faster than an uncatalyzed control reaction. The amine-catalyzed reactions yielded aldotriose (glyceraldehyde), ketotriose (dihydroxyacetone), aldotetroses (erythrose and threose), ketotetrose (erythrulose), pyruvaldehyde, acetaldehyde, glyoxal, pyruvate, glyoxylate, and several unindentified carbonyl products. The concentrations of the carbonyl products, except pyruvate and ketotetrose, initially increased and then declined during the reaction, indicating their ultimate conversion to other products (like larger sugars or pyruvate). The uncatalyzed control reaction yielded no pyruvate or glyoxylate, and only trace amounts of pyruvaldehyde, acetaldehyde and glyoxal. In the presence of 15 mM catalytic primary amine, such as alanine, the rates of triose and pyruvaldehyde of synthesis were about 15-times and 1200-times faster, respectively, than the uncatalyzed reaction. Since previous studies established that alanine is synthesized from glycolaldehyde and formaldehyde via pyruvaldehyde as its direct precursor, the demonstration that the alanine catalyzes the conversion of glycolaldehyde and formaldehyde to pyruvaldehyde indicates that this synthetic pathway is capable of autocatalysis. The relevance of this synthetic process, named the Sugar Model, to the origin of life is discussed.

  10. The sugar model: catalysis by amines and amino acid products

    NASA Technical Reports Server (NTRS)

    Weber, A. L.

    2001-01-01

    Ammonia and amines (including amino acids) were shown to catalyze the formation of sugars from formaldehyde and glycolaldehyde, and the subsequent conversion of sugars to carbonylcontaining products under the conditions studied (pH 5.5 and 50 degrees C). Sterically unhindered primary amines were better catalysts than ammonia, secondary amines, and sterically hindered primary amines (i.e. alpha-aminoisobutyric acid). Reactions catalyzed by primary amines initially consumed formaldehyde and glycolaldehyde about 15-20 times faster than an uncatalyzed control reaction. The amine-catalyzed reactions yielded aldotriose (glyceraldehyde), ketotriose (dihydroxyacetone), aldotetroses (erythrose and threose), ketotetrose (erythrulose), pyruvaldehyde, acetaldehyde, glyoxal, pyruvate, glyoxylate, and several unindentified carbonyl products. The concentrations of the carbonyl products, except pyruvate and ketotetrose, initially increased and then declined during the reaction, indicating their ultimate conversion to other products (like larger sugars or pyruvate). The uncatalyzed control reaction yielded no pyruvate or glyoxylate, and only trace amounts of pyruvaldehyde, acetaldehyde and glyoxal. In the presence of 15 mM catalytic primary amine, such as alanine, the rates of triose and pyruvaldehyde of synthesis were about 15-times and 1200-times faster, respectively, than the uncatalyzed reaction. Since previous studies established that alanine is synthesized from glycolaldehyde and formaldehyde via pyruvaldehyde as its direct precursor, the demonstration that the alanine catalyzes the conversion of glycolaldehyde and formaldehyde to pyruvaldehyde indicates that this synthetic pathway is capable of autocatalysis. The relevance of this synthetic process, named the Sugar Model, to the origin of life is discussed.

  11. Conjugated linoleic acid-enriched beef production.

    PubMed

    Mir, Priya S; McAllister, Timothy A; Scott, Shannon; Aalhus, Jennifer; Baron, Vern; McCartney, Duane; Charmley, Edward; Goonewardene, Laki; Basarab, John; Okine, Erasmus; Weselake, Randall J; Mir, Zahir

    2004-06-01

    Canadian beef consumption is approximately 31 kg per annum, or a third of all meats consumed. Beef is a nutrient-rich food, providing good quality protein, vitamins B-6 and B-12, niacin, iron, and zinc. However, animal fats have gained the reputation of being less healthy. The identification of the anticarcinogenic effects of beef extracts due to the presence of conjugated linoleic acid (CLA) has heightened interest in increasing the amount of CLA deposited in beef. Beef cattle produce CLA and deposit these compounds in the meat; thus, beef consumers can receive bioformed CLA. Beef contains both of the bioactive CLA isomers, namely, cis-9, trans-11 and trans-10, cis-12. The relative content of these CLA isomers in beef depends on the feeds consumed by the animals during production. Feeding cattle linoleic acid-rich oils for extended periods of time increases the CLA content of beef. Depending on the type and relative maturity of the pasture, beef from pasture-fed cattle may have a higher CLA content than beef from grain- or silage-fed cattle. In feedlot animals fed high-grain diets, inclusion of dietary oil along with hay during both the growth and finishing phases led to an increase in CLA content from 2.8 to 14 mg/g beef fat, which would provide 77 mg CLA in an 85-g serving of beef. The CLAs appear to be concentrated in intramuscular and subcutaneous fat of beef cattle, with the CLA trans-10, cis-12 isomer being greater in the subcutaneous fat. PMID:15159258

  12. 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

  13. Backsurging perforations can increase production rates

    SciTech Connect

    Brieger, E.F.

    1991-07-01

    Subjecting formations to a large pressure differential or underbalance is a common means of surging perforations to remove damage and increase flow from oil and gas wells. Underbalanced perforating, a standard industry completion technique, is normally used to obtain the pressure differentials intended to dislodge debris from perforations and flush the surrounding compacted zone. Gradually applied pressure underbalance can be achieved by swabbing or jetting to reduce hydrostatic head. Suddenly applied underbalance is achieved by evacuating the tubing in conjunction with a rupture disc, tubing-conveyed perforating systems or by using a new wireline-set, through-tubing backsurge tool. These techniques, except for the through-tubing method, are often utilized only during later workovers due to the expense and difficulty of achieving an adequate underbalance. Many operators prefer to perforate in balanced or overbalanced pressures conditions. This typically leaves perforations completely or partially plugged with gun debris, mud solids and shattered formation material that has been recompacted. Production logging shows that wells often produce from only 10 to 20% of the total interval apparently because of ineffective, plugged perforations.

  14. Analysis of cyclic pyrolysis products formed from amino acid monomer.

    PubMed

    Choi, Sung-Seen; Ko, Ji-Eun

    2011-11-18

    Amino acid was mixed with silica and tetramethylammonium hydroxide (TMAH) to favor pyrolysis of amino acid monomer. The pyrolysis products formed from amino acid monomer were using GC/MS and GC. 20 amino acids of alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine were analyzed. The pyrolysis products were divided into cyclic and non-cyclic products. Among the 20 amino acids, arginine, asparagine, glutamic acid, glutamine, histidine, lysine, and phenylalanine generated cyclic pyrolysis products of the monomer. New cyclic pyrolysis products were formed by isolation of amino acid monomers. They commonly had polar side functional groups to 5-, 6-, or 7-membered ring structure. Arginine, asparagine, glutamic acid, glutamine, histidine, and phenylalanine generated only 5- or 6-membered ring products. However, lysine generated both 6- and 7-membered ring compounds. Variations of the relative intensities of the cyclic pyrolysis products with the pyrolysis temperature and amino acid concentration were also investigated. PMID:21993510

  15. Production rate of planktonic bacteria in the north basin of Lake Biwa, Japan

    SciTech Connect

    Nagata, T.

    1987-12-01

    Vertical and seasonal variations in the cell number and production rate of planktonic bacteria were investigated at a pelagic site (water depth, ca. 72 m) of the north basin of Lake Biwa during April to October, 1986. The (methyl-/sup 3/H) thymidine uptake rate into a cold tricholoroacetic acid-insoluble fraction and the frequency of dividing cells (FDCs) were measured for each sample as indices of the bacterial production rate. The seasonal data of bacterial number, thymidine uptake rate, and bacterial growth rate based on the FDCs were correlated with one another. These bacterial variables were not correlated positively with the chlorophyll a concentration. Vertically, the maxima of both bacterial number and the thymidine uptake rate were found in the euphotic zone. The direct counting of bacteria and the measurements of thymidine uptake rate combined with the size-fractionation method revealed that more than 90% of the bacterial biomass and production rate were attributed to unattached bacteria throughout the investigation period. The carbon flux estimates of bacterial production were less certain due to the variability of the conversion factor for the thymidine uptake method and that of the calibration for the FDC method, but even when the conservative range of bacterial net production rate was used (5 to 60 ..mu..g of carbon per liter per day), it can be suggested that bacterial net production in the investigated area was a significant fraction (ca. 30%) of the level of the primary production rate in the same water basin.

  16. 40 CFR 721.10679 - Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alkylstannylene ester, reaction products with inorganic acid tetra alkyl ester (generic). 721.10679 Section 721... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10679 Carboxylic acid, substituted alkylstannylene ester, reaction products with inorganic acid tetra alkyl...

  17. Production of high molecular weight polylactic acid

    SciTech Connect

    Bonsignore, Patrick V.

    1995-01-01

    A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  18. Production of high molecular weight polylactic acid

    SciTech Connect

    Bonsignore, P.V.

    1995-11-28

    A degradable high molecular weight poly(lactic acid) is described. The poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  19. Graduation Rates and Accountability: Regressions versus Production Frontiers

    ERIC Educational Resources Information Center

    Archibald, Robert B.; Feldman, David H.

    2008-01-01

    This paper suggests an alternative to the standard practice of measuring the graduation rate performance using regression analysis. The alternative is production frontier analysis. Production frontier analysis is appealing because it compares an institution's graduation rate to the best performance instead of the average performance. The paper…

  20. Microbial production of propionic acid and vitamin B12 using molasses or sugar.

    PubMed

    Quesada-Chanto, A; Afschar, A S; Wagner, F

    1994-06-01

    With a cell concentration of 125 g dry biomass l-1 and a dilution rate of 0.1 h-1, Propionibacterium acidipropionici produces 30 g propionic acid l-1 from sugar with a productivity of 3 g l-1 h-1. The yield of propionic acid is approx. 0.36-0.45 g propionic acid g-1 sucrose and is independent of the dilution rate and cell concentration. Acetic acid is an unwanted by-product in the production of propionic acid. The concentration of acetic acid only increases slightly when the cell concentration is increased. A two-stage fermentation process was developed for the conversion of sugar or molasses of various types to propionic acid and vitamin B12. By fermentation of blackstrap molasses (from sugar beet and sugar cane) in the first fermentation stage 17.7 g propionic acid l-1 with a yield of 0.5 g propionic acid g-1 carbohydrate was produced with a dilution rate of 0.25 h-1. In the second stage 49 mg vitamin B12 1-1 was produced at a dilution rate of 0.03 h-1. PMID:7765100

  1. Microbial granulation for lactic acid production.

    PubMed

    Kim, Dong-Hoon; Lee, Mo-Kwon; Hwang, Yuhoon; Im, Wan-Taek; Yun, Yeo-Myeong; Park, Chul; Kim, Mi-Sun

    2016-01-01

    This work investigated the formation of microbial granules to boost the productivity of lactic acid (LA). The flocculated form of LA-producing microbial consortium, dominated by Lactobacillus sp. (91.5% of total sequence), was initially obtained in a continuous stirred-tank reactor (CSTR), which was fed with 2% glucose and operated at a hydraulic retention time (HRT) of 12 h and pH 5.0 ± 0.1 under a thermophilic condition (50°C). The mixed liquor in the CSTR was then transferred to an up-flow anaerobic sludge blanket reactor (UASB). The fermentation performance and granulation process were monitored with a gradual decrease of HRT from 8.0 to 0.17 h, corresponding to an increase in the substrate loading from 60 to 2,880 g glucose L(-1) d(-1) . As the operation continued, the accumulation of biomass in the UASB was clearly observed, which changed from flocculent to granular form with decrease in HRT. Up to the HRT decrease to 0.5 h, the LA concentration was maintained at 19-20 g L(-1) with over 90% of substrate removal efficiency. However, further decrease of HRT resulted in a decrease of LA concentration with increase in residual glucose. Nevertheless, the volumetric LA productivity continuously increased, reaching 67 g L-fermenter (-1) h(-1) at HRT 0.17 h. The size of LA-producing granules and hydrophobicity gradually increased with decrease in HRT, reaching 6.0 mm and 60%, respectively. These biogranules were also found to have high settling velocities and low porosities, ranging 2.69-4.73 cm s(-1) and 0.39-0.92, respectively. PMID:25925200

  2. Efficient lactobionic acid production from whey by Pseudomonas taetrolens under pH-shift conditions.

    PubMed

    Alonso, Saúl; Rendueles, Manuel; Díaz, Mario

    2011-10-01

    Lactobionic acid finds applications in the fields of pharmaceuticals, cosmetics and medicine. The production of lactobionic acid from whey by Pseudomonas taetrolens was studied in shake-flasks and in a bioreactor. Shake-flask experiments showed that lactobionic acid was a non-growth associated product. A two-stage pH-shift bioconversion strategy with a pH-uncontrolled above 6.5 during the growth phase and maintained at 6.5 during cumulative production was adopted in bioreactor batch cultures. An inoculation level of 30% promoted high cell culture densities that triggered lactobionic acid production at a rate of 1.12 g/Lh. This methodology displayed efficient bioconversion with cheese whey as an inexpensive substrate for lactobionic acid production. PMID:21862326

  3. Chicoric acid: chemistry, distribution, and production

    NASA Astrophysics Data System (ADS)

    Lee, Jungmin; Scagel, Carolyn

    2013-12-01

    Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed.

  4. Chicoric acid: chemistry, distribution, and production

    PubMed Central

    Lee, Jungmin; Scagel, Carolyn F.

    2013-01-01

    Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 63 genera and species have been found to contain chicoric acid, and while the compound is used as a processing quality indicator, it may also have useful health benefits. This review of chicoric acid summarizes research findings and highlights gaps in research knowledge for investigators, industry stakeholders, and consumers alike. Additionally, chicoric acid identification, and quantification methods, biosynthesis, processing improvements to increase chicoric acid retention, and potential areas for future research are discussed. PMID:24790967

  5. High emission rate of sulfuric acid from Bezymianny volcano, Kamchatka

    NASA Astrophysics Data System (ADS)

    Zelenski, Michael; Taran, Yuri; Galle, Bo

    2015-09-01

    High concentrations of primary sulfuric acid (H2SO4) in fumarolic gases and high emission rate of sulfuric acid aerosol in the plume were measured at Bezymianny volcano, an active dome-growing andesitic volcano in central Kamchatka. Using direct sampling, filter pack sampling, and differential optical absorption spectroscopy measurements, we estimated an average emission of H2SO4 at 243 ± 75 t/d in addition to an average SO2 emission of 212 ± 65 t/d. The fumarolic gases of Bezymianny correspond to arc gases released by several magma bodies at different stages of degassing and contain 25-92% of entrained air. H2SO4 accounts for 6-87 mol% of the total sulfur content, 42.8 mol% on average, and SO2 is the rest. The high H2SO4 in Bezymianny fumaroles can be explained by catalytic oxidation of SO2 inside the volcanic dome. Because sulfate aerosol is impossible to measure remotely, the total sulfur content in a plume containing significant H2SO4 may be seriously underestimated.

  6. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  7. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  8. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  9. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  10. 40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific...

  11. Engineering a cyanobacterial cell factory for production of lactic acid.

    PubMed

    Angermayr, S Andreas; Paszota, Michal; Hellingwerf, Klaas J

    2012-10-01

    Metabolic engineering of microorganisms has become a versatile tool to facilitate production of bulk chemicals, fuels, etc. Accordingly, CO(2) has been exploited via cyanobacterial metabolism as a sustainable carbon source of biofuel and bioplastic precursors. Here we extended these observations by showing that integration of an ldh gene from Bacillus subtilis (encoding an l-lactate dehydrogenase) into the genome of Synechocystis sp. strain PCC6803 leads to l-lactic acid production, a phenotype which is shown to be stable for prolonged batch culturing. Coexpression of a heterologous soluble transhydrogenase leads to an even higher lactate production rate and yield (lactic acid accumulating up to a several-millimolar concentration in the extracellular medium) than those for the single ldh mutant. The expression of a transhydrogenase alone, however, appears to be harmful to the cells, and a mutant carrying such a gene is rapidly outcompeted by a revertant(s) with a wild-type growth phenotype. Furthermore, our results indicate that the introduction of a lactate dehydrogenase rescues this phenotype by preventing the reversion. PMID:22865063

  12. Nitrogen mineralization rates of the acidic, xeric soils of the New Jersey Pinelands: field rates

    SciTech Connect

    Poovarodom, S.; Tate, R.L. III; Bloom, R.A.

    1988-04-01

    Using the buried-bag procedure, the authors quantified nitrogen mineralization rates in the xeric, acidic Lakehurst, and Atsion sands of the New Jersey Pine Barrens. Average annual nitrogen yields in the upper 15 cm for the Lakehurst and the Atsion sands were 38.4 and 53.0 kg N/ha, corresponding to 4.5 and 2.5% of the total nitrogen, respectively. Net nitrogen mineralization in both soils exhibited distinct seasonal patterns with maxima in summer and minimum rates in the winter. Nitrification accounted for only 5% of the total N mineralized in both soils. This is consistent with the finding of low populations of autotrophic nitrifiers in these soils.

  13. Methods for producing 3-hydroxypropionic acid and other products

    DOEpatents

    Lynch, Michael D.; Gill, Ryan T.; Lipscomb, Tanya E. W.

    2016-07-12

    This invention relates to metabolically engineered microorganism strains, such as bacterial strains, in which there is an increased utilization of malonyl-CoA for production of a chemical product, which includes 3-hydroxypropionic acid.

  14. Biotechnological routes based on lactic acid production from biomass.

    PubMed

    Gao, Chao; Ma, Cuiqing; Xu, Ping

    2011-01-01

    Lactic acid, the most important hydroxycarboxylic acid, is now commercially produced by the fermentation of sugars present in biomass. In addition to its use in the synthesis of biodegradable polymers, lactic acid can be regarded as a feedstock for the green chemistry of the future. Different potentially useful chemicals such as pyruvic acid, acrylic acid, 1,2-propanediol, and lactate ester can be produced from lactic acid via chemical and biotechnological routes. Here, we reviewed the current status of the production of potentially valuable chemicals from lactic acid via biotechnological routes. Although some of the reactions described in this review article are still not applicable at current stage, due to their "greener" properties, biotechnological processes for the production of lactic acid derivatives might replace the chemical routes in the future. PMID:21846500

  15. New uses of bioglycerin: production of arachidonic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Filamentous fungi of the genus Mortierella are known to produce arachidonic acid from glucose and M. alpina is currently used in industrial scale production of arachidonic acid in Japan. In anticipation of a large excess of co-product bioglycerin from the national biodiesel program, we would like ...

  16. Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.

    PubMed

    Mitsuhashi, Satoshi

    2014-04-01

    Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine). PMID:24679256

  17. Fed-batch production of poly-3-hydroxydecanoate from decanoic acid.

    PubMed

    Gao, Jie; Ramsay, Juliana A; Ramsay, Bruce A

    2016-01-20

    Decanoic acid is an ideal substrate for the synthesis of medium-chain-length poly-3-hydroxyalkanoate (MCL-PHA), but its use for this purpose has only previously been studied in shake-flasks likely due to its surfactant properties, low aqueous solubility and high melting temperature. A fed-batch fermentation process was developed for the production of MCL-PHA from decanoic acid using Pseudomonas putida KT2440. Decanoic acid was kept in liquid form by heating or by mixing with acetic acid to prevent crystallization. Different ratios of decanoic acid:acetic acid:glucose (DA:AA:G) were fed to produce a specific growth rate of 0.15 h(-1). This method produced a maximum of 39 g L(-1) dry biomass containing 67% MCL-PHA when the DA:AA:G ratio was 5:1:4. However, a declining growth rate occurred in the late stage of fermentation, resulting in decanoic acid accumulation in the bioreactor leading to foaming. The duration of MCL-PHA production was extended by shifting from exponential to linear feeding before accumulation of decanoic acid. This resulted in 75 g L(-1) biomass containing 74% PHA and an overall PHA productivity of 1.16 g L(-1)h(-1) with the production of each gram of PHA requiring only 1.16 g of decanoic acid. The final PHA composition (on a molar basis) was 78% 3-hydroxydecanoate, 11% 3-hydroxyoctanoate and 11% 3-hydroxyhexanoate. PMID:26689481

  18. Reaction rate and products for the reaction O/3P/ + H2CO

    NASA Technical Reports Server (NTRS)

    Chang, J. S.; Barker, J. R.

    1979-01-01

    A study of reaction kinetics of O + H2CO in a discharge-flow system using mass spectrometric detection of reactants and products is presented. It was performed under both oxygen-atom-rich and formaldehyde-rich conditions over the 296 to 437 K range, showing that the global bimolecular rate constant is in agreement with other studies. This study differs from others in that the reaction products can be observed, and a substantial yield of a primary reaction product was measured with a mass spectral peak at m/e=44. This suggests that the global reaction rate probably consists of combination, as well as of simple abstraction. For the combination, one hypothesis is that triplet dioxymethylene is formed which polymerizes to triplet formic acid; the vibrationally excited triplet formic acid may decompose to form several sets of products, including HCO + OH and HCO2 + H.

  19. Effects of acid deposition on agricultural production

    SciTech Connect

    Moskowitz, P.D.; Medeiros, W.H.; Oden, N.L.; Thode, H.C. Jr.; Coveney, E.A.; Jacobson, J.S.; Rosenthal, R.E.; Evans, L.S.; Lewin, K.F.; Allen, F.L.

    1985-09-01

    A preliminary assessment, both qualitative and quantitative, was carried out on the effects of acid deposition on agriculture. An inventory was made of US crops exposed to different acid deposition levels in 1982. Most crops (valued at more than $50 billion) were exposed to annual average acid deposition levels greater than pH 4.6, but crops worth more than $220 billion were exposed to even lower pH levels. Published results of experiments on crop response to acid deposition have not identified any single crop as being consistently sensitive, and suggest that present levels of acidic precipitation in the US are not significantly affecting growth and yield of crops. Because relatively few experiments appropriate to a quantitative acid deposition assessment have been conducted, the quantitative section is necessarily based on a restricted data set. Corn, potatoes, and soybeans have been studied in experimental environments which simulate agronomic conditions and which have adequate statistical power for yield estimates; only some varieties of soybeans have demonstrated statistically significant sensitivity to acid deposition.

  20. Ascorbic acid and rates of cognitive decline in Alzheimer's disease.

    PubMed

    Bowman, Gene L; Dodge, Hiroko; Frei, Balz; Calabrese, Carlo; Oken, Barry S; Kaye, Jeffrey A; Quinn, Joseph F

    2009-01-01

    The brain maintains high levels of ascorbic acid (AA) despite a concentration gradient favoring diffusion from brain to peripheral tissues. Dietary antioxidants, including AA, appear to modify the risk of Alzheimer's disease (AD). The objective of this study was to test the hypothesis that neurodegeneration in AD is modified by brain levels of AA. Thirty-two patients with mild to moderate AD participated in a biomarker study involving standardized clinical assessments over one year. Cerebrospinal fluid (CSF) and serum were collected at baseline for AA and albumin content. Cognitive measures were collected at baseline and one year. CSF and plasma AA failed to predict cognitive decline independently, however, CSF: plasma AA ratio did. After adding CSF Albumin Index (an established marker of blood-brain barrier integrity) to the regression models the effect of CSF: plasma AA ratio as a predictor of cognitive decline was weakened. CSF: plasma AA ratio predicts rate of decline in AD. This relationship may indicate that the CSF: plasma AA ratio is an index of AA availability to the brain or may be an artifact of a relationship between blood-brain barrier impairment and neurodegeneration. PMID:19158425

  1. Production of extracellular fatty acid using engineered Escherichia coli

    PubMed Central

    2012-01-01

    Background As an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics. Results In this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3) improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL) produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired product. The strain p

  2. Metabolic engineering of Yarrowia lipolytica for itaconic acid production.

    PubMed

    Blazeck, John; Hill, Andrew; Jamoussi, Mariam; Pan, Anny; Miller, Jarrett; Alper, Hal S

    2015-11-01

    Itaconic acid is a naturally produced organic acid with diverse applications as a replacement for petroleum derived products. However, its industrial viability as a bio-replacement has been restricted due to limitations with native producers. In this light, Yarrowia lipolytica is an excellent potential candidate for itaconic acid production due to its innate capacity to accumulate citric acid cycle intermediates and tolerance to lower pH. Here, we demonstrate the capacity to produce itaconic acid in Y. lipolytica through heterologous expression of the itaconic acid synthesis enzyme, resulting in an initial titer of 33 mg/L. Further optimizations of this strain via metabolic pathway engineering, enzyme localization, and media optimization strategies enabled 4.6g/L of itaconic acid to be produced in bioreactors, representing a 140-fold improvement over initial titer. Moreover, these fermentation conditions did not require additional nutrient supplementation and utilized a low pH condition that enabled the acid form of itaconic acid to be produced. Overall yields (0.058 g/g yield from glucose) and maximum productivity of 0.045 g/L/h still provide areas for future strain improvement. Nevertheless, this work demonstrates that Y. lipolytica has the potential to serve as an industrially relevant platform for itaconic acid production. PMID:26384571

  3. Heterologous production of caffeic acid from tyrosine in Escherichia coli.

    PubMed

    Rodrigues, J L; Araújo, R G; Prather, K L J; Kluskens, L D; Rodrigues, L R

    2015-04-01

    Caffeic acid is a plant secondary metabolite and its biological synthesis has attracted increased attention due to its beneficial effects on human health. In this study, Escherichia coli was engineered for the production of caffeic acid using tyrosine as the initial precursor of the pathway. The pathway design included tyrosine ammonia lyase (TAL) from Rhodotorula glutinis to convert tyrosine to p-coumaric acid and 4-coumarate 3-hydroxylase (C3H) from Saccharothrix espanaensis or cytochrome P450 CYP199A2 from Rhodopseudomonas palustris to convert p-coumaric acid to caffeic acid. The genes were codon-optimized and different combinations of plasmids were used to improve the titer of caffeic acid. TAL was able to efficiently convert 3mM of tyrosine to p-coumaric acid with the highest production obtained being 2.62mM (472mg/L). CYP199A2 exhibited higher catalytic activity towards p-coumaric acid than C3H. The highest caffeic acid production obtained using TAL and CYP199A2 and TAL and C3H was 1.56mM (280mg/L) and 1mM (180mg/L), respectively. This is the first study that shows caffeic acid production using CYP199A2 and tyrosine as the initial precursor. This study suggests the possibility of further producing more complex plant secondary metabolites like flavonoids and curcuminoids. PMID:25765308

  4. By-products of electrochemical synthesis of suberic acid

    SciTech Connect

    Shirobokova, O.I.; Adamov, A.A.; Freidlin, G.N.; Antonenko, N.S.; Grudtsyn, Yu.D.

    1988-05-10

    By-products of the electrochemical synthesis of dimethyl suberate from glutaric anhydride were studied. This is isolated by thermal dehydration of a mixture of lower dicarboxylic acids that are wastes from the production of adipic acid. To isolate the by-products, they used the methods of vacuum rectification and preparative gas-liquid chromatography, and for their identification, PMR, IR spectroscopy, gas-liquid chromatography, and other known physicochemical methods of investigation.

  5. Gas-Phase Formation Rates of Nitric Acid and Its Isomers Under Urban Conditions

    NASA Technical Reports Server (NTRS)

    Okumura, M.; Mollner, A. K.; Fry, J. L.; Feng, L.

    2005-01-01

    Ozone formation in urban smog is controlled by a complex set of reactions which includes radical production from photochemical processes, catalytic cycles which convert NO to NO2, and termination steps that tie up reactive intermediates in long-lived reservoirs. The reaction OH + NO2 + M -4 HONO2 + M (la) is a key termination step because it transforms two short-lived reactive intermediates, OH and NO2, into relatively long-lived nitric acid. Under certain conditions (low VOC/NOx), ozone production in polluted urban airsheds can be highly sensitive to this reaction, but the rate parameters are not well constrained. This report summarizes the results of new laboratory studies of the OH + NO2 + M reaction including direct determination of the overall rate constant and branching ratio for the two reaction channels under atmospherically relevant conditions.

  6. A chamber study of the influence of boreal BVOC emissions and sulphuric acid on nanoparticle formation rates at ambient concentrations

    NASA Astrophysics Data System (ADS)

    Dal Maso, M.; Liao, L.; Wildt, J.; Kiendler-Scharr, A.; Kleist, E.; Tillmann, R.; Sipilä, M.; Hakala, J.; Lehtipalo, K.; Ehn, M.; Kerminen, V.-M.; Kulmala, M.; Worsnop, D.; Mentel, T.

    2014-12-01

    Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich Plant-Atmosphere Simulation Chamber with instrumentation for the detection of sulphuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulphuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOC). We present direct laboratory observations of nanoparticle formation from sulphuric acid and realistic BVOC precursor vapor mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulphuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulphuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

  7. A chamber study of the influence of boreal BVOC emissions and sulfuric acid on nanoparticle formation rates at ambient concentrations

    NASA Astrophysics Data System (ADS)

    Dal Maso, M.; Liao, L.; Wildt, J.; Kiendler-Scharr, A.; Kleist, E.; Tillmann, R.; Sipilä, M.; Hakala, J.; Lehtipalo, K.; Ehn, M.; Kerminen, V.-M.; Kulmala, M.; Worsnop, D.; Mentel, T.

    2016-02-01

    Aerosol formation from biogenic and anthropogenic precursor trace gases in continental background areas affects climate via altering the amount of available cloud condensation nuclei. Significant uncertainty still exists regarding the agents controlling the formation of aerosol nanoparticles. We have performed experiments in the Jülich plant-atmosphere simulation chamber with instrumentation for the detection of sulfuric acid and nanoparticles, and present the first simultaneous chamber observations of nanoparticles, sulfuric acid, and realistic levels and mixtures of biogenic volatile compounds (BVOCs). We present direct laboratory observations of nanoparticle formation from sulfuric acid and realistic BVOC precursor vapour mixtures performed at atmospherically relevant concentration levels. We directly measured particle formation rates separately from particle growth rates. From this, we established that in our experiments, the formation rate was proportional to the product of sulfuric acid and biogenic VOC emission strength. The formation rates were consistent with a mechanism in which nucleating BVOC oxidation products are rapidly formed and activate with sulfuric acid. The growth rate of nanoparticles immediately after birth was best correlated with estimated products resulting from BVOC ozonolysis.

  8. Kinetic modeling of lactic acid production from batch submerged fermentation of cheese whey

    SciTech Connect

    Tango, M.S.A.; Ghaly, A.E.

    1999-12-01

    A kinetic model for the production of lactic acid through batch submerged fermentation of cheese whey using Lactobacillus helveticus was developed. The model accounts for the effect of substrate limitation, substrate inhibition, lactic acid inhibition, maintenance energy and cell death on the cell growth, substrate utilization, and lactic acid production during the fermentation process. The model was evaluated using experimental data from Tango and Ghaly (1999). The predicted results obtained from the model compared well with experimental (R{sup 2} = 0.92--0.98). The model was also used to investigate the effect of the initial substrate concentration on the lag period, fermentation time, specific growth rate, and cell productivity during batch fermentation. The maximum specific growth rate ({micro}{sub m}), the saturation constant (K{sub S}), the substrate inhibition constant (K{sub IS}), and the lactic acid inhibition constant (K{sub IP}) were found to be 0.25h{sup {minus}1}, 0.9 g/L, 250.0 g/L, and 60.0 g/L, respectively. High initial lactose concentration in cheese whey reduced both the specific growth rate and substrate utilization rate due to the substrate inhibition phenomenon. The maximum lactic acid production occurred at about 100 g/L initial lactose concentration after 40 h of fermentation. The maximum lactic acid concentration above which Lactobacillus helveticus did not grow was found to be 80.0 g/L.

  9. Microalgae from domestic wastewater facility's high rate algal pond: Lipids extraction, characterization and biodiesel production.

    PubMed

    Drira, Neila; Piras, Alessandra; Rosa, Antonella; Porcedda, Silvia; Dhaouadi, Hatem

    2016-04-01

    In this study, the harvesting of a biomass from a high rate algal pond (HRAP) of a real-scale domestic wastewater treatment facility and its potential as a biomaterial for the production of biodiesel were investigated. Increasing the medium pH to 12 induced high flocculation efficiency of up to 96% of the biomass through both sweep flocculation and charge neutralization. Lipids extracted by ultrasounds from this biomass contained around 70% of fatty acids, with palmitic and stearic acids being the most abundant. The extract obtained by supercritical CO2 contained 86% of fatty acids. Both conventional solvents extracts contained only around 10% of unsaturated fats, whereas supercritical CO2 extract contained more than 40% of unsaturated fatty acids. This same biomass was also subject to direct extractive-transesterification in a microwave reactor to produce fatty acid methyl esters, also known as, raw biodiesel. PMID:26866759

  10. Effect of pH and dilution rate on specific production rate of extra cellular metabolites by Lactobacillus salivarius UCO_979C in continuous culture.

    PubMed

    Valenzuela, Javier Ferrer; Pinuer, Luis; Cancino, Apolinaria García; Yáñez, Rodrigo Bórquez

    2015-08-01

    The effect of pH and dilution rate on the production of extracellular metabolites of Lactobacillus salivarius UCO_979 was studied. The experiments were carried out in continuous mode, with chemically defined culture medium at a temperature of 37 °C, 200 rpm agitation and synthetic air flow of 100 ml/min. Ethanol, acetic acid, formic acid, lactic acid and glucose were quantified through HPLC, while exopolysaccharide (EPS) was extracted with ethanol and quantified through the Dubois method. The results showed no linear trends for the specific production of lactic acid, EPS, acetic acid and ethanol, while the specific glucose consumption and ATP production rates showed linear trends. There was a metabolic change of the strain for dilution rates below 0.3 h(-1). The pH had a significant effect on the metabolism of the strain, which was evidenced by a higher specific glucose consumption and increased production of ATP at pH 6 compared with that obtained at pH 7. This work shows not only the metabolic capabilities of L. salivarius UCO_979C, but also shows that it is possible to quantify some molecules associated with its current use as gastrointestinal probiotic, especially regarding the production of organic acids and EPS. PMID:25805342

  11. Effects of Light and Temperature on Fatty Acid Production in Nannochloropsis Salina

    SciTech Connect

    Van Wagenen, Jonathan M.; Miller, Tyler W.; Hobbs, Samuel J.; Hook, Paul W.; Crowe, Braden J.; Huesemann, Michael H.

    2012-03-12

    Accurate prediction of algal biofuel yield will require empirical determination of physiological responses to the climate, particularly light and temperature. One strain of interest, Nannochloropsis salina, was subjected to ranges of light intensity (5-850 {mu}mol m{sup -2} s{sup -1}) and temperature (13-40 C); exponential growth rate, total fatty acids (TFA) and fatty acid composition were measured. The maximum acclimated growth rate was 1.3 day{sup -1} at 23 C and 250 {mu}mol m{sup -2} s{sup -1}. Fatty acids were detected by gas chromatography with flame ionization detection (GC-FID) after transesterification to corresponding fatty acid methyl esters (FAME). A sharp increase in TFA containing elevated palmitic acid (C16:0) and palmitoleic acid (C16:1) during exponential growth at high light was observed, indicating likely triacylglycerol accumulation due to photo-oxidative stress. Lower light resulted in increases in the relative abundance of unsaturated fatty acids; in thin cultures, increases were observed in palmitoleic and eicosapentaenoeic acids (C20:5{omega}3). As cultures aged and the effective light intensity per cell converged to very low levels, fatty acid profiles became more similar and there was a notable increase of oleic acid (C18:1{omega}9). The amount of unsaturated fatty acids was inversely proportional to temperature, demonstrating physiological adaptations to increase membrane fluidity. This data will improve prediction of fatty acid characteristics and yields relevant to biofuel production.

  12. Ozone production rates as a function of NOx abundances and HOx production rates in the Nashville urban plume

    NASA Astrophysics Data System (ADS)

    Thornton, J. A.; Wooldridge, P. J.; Cohen, R. C.; Martinez, M.; Harder, H.; Brune, W. H.; Williams, E. J.; Roberts, J. M.; Fehsenfeld, F. C.; Hall, S. R.; Shetter, R. E.; Wert, B. P.; Fried, A.

    2002-06-01

    Tropospheric O3 concentrations are functions of the chain lengths of NOx (NOx ≡ NO + NO2) and HOx (HOx ≡ OH + HO2 + RO2) radical catalytic cycles. For a fixed HOx source at low NOx concentrations, kinetic models indicate the rate of O3 production increases linearly with increases in NOx concentrations (NOx limited). At higher NOx concentrations, kinetic models predict ozone production rates decrease with increasing NOx (NOx saturated). We present observations of NO, NO2, O3, OH, HO2, H2CO, actinic flux, and temperature obtained during the 1999 Southern Oxidant Study from June 15 to July 15, 1999, at Cornelia Fort Airpark, Nashville, Tennessee. The observations are used to evaluate the instantaneous ozone production rate (PO3) as a function of NO abundances and the primary HOx production rate (PHOx). These observations provide quantitative evidence for the response of PO3 to NOx. For high PHOx (0.5 < PHOx < 0.7 ppt/s), O3 production at this site increases linearly with NO to ~500 ppt. PO3 levels out in the range 500-1000 ppt NO and decreases for NO above 1000 ppt. An analysis along chemical coordinates indicates that models of chemistry controlling peroxy radical abundances, and consequently PO3, have a large error in the rate or product yield of the RO2 + HO2 reaction for the classes of RO2 that predominate in Nashville. Photochemical models and our measurements can be forced into agreement if the product of the branching ratio and rate constant for organic peroxide formation, via RO2 + HO2 -> ROOH + O2, is reduced by a factor of 3-12. Alternatively, these peroxides could be rapidly photolyzed under atmospheric conditions making them at best a temporary HOx reservoir. This result implies that O3 production in or near urban areas with similar hydrocarbon reactivity and HOx production rates may be NOx saturated more often than current models suggest.

  13. Thermodynamic prediction of hydrogen production from mixed-acid fermentations.

    PubMed

    Forrest, Andrea K; Wales, Melinda E; Holtzapple, Mark T

    2011-10-01

    The MixAlco™ process biologically converts biomass to carboxylate salts that may be chemically converted to a wide variety of chemicals and fuels. The process utilizes lignocellulosic biomass as feedstock (e.g., municipal solid waste, sewage sludge, and agricultural residues), creating an economic basis for sustainable biofuels. This study provides a thermodynamic analysis of hydrogen yield from mixed-acid fermentations from two feedstocks: paper and bagasse. During batch fermentations, hydrogen production, acid production, and sugar digestion were analyzed to determine the energy selectivity of each system. To predict hydrogen production during continuous operation, this energy selectivity was then applied to countercurrent fermentations of the same systems. The analysis successfully predicted hydrogen production from the paper fermentation to within 11% and the bagasse fermentation to within 21% of the actual production. The analysis was able to faithfully represent hydrogen production and represents a step forward in understanding and predicting hydrogen production from mixed-acid fermentations. PMID:21875794

  14. Mapping {sup 15}O Production Rate for Proton Therapy Verification

    SciTech Connect

    Grogg, Kira; Alpert, Nathaniel M.; Zhu, Xuping; Min, Chul Hee; Testa, Mauro; Winey, Brian; Normandin, Marc D.; Shih, Helen A.; Paganetti, Harald; Bortfeld, Thomas; El Fakhri, Georges

    2015-06-01

    Purpose: This work was a proof-of-principle study for the evaluation of oxygen-15 ({sup 15}O) production as an imaging target through the use of positron emission tomography (PET), to improve verification of proton treatment plans and to study the effects of perfusion. Methods and Materials: Dynamic PET measurements of irradiation-produced isotopes were made for a phantom and rabbit thigh muscles. The rabbit muscle was irradiated and imaged under both live and dead conditions. A differential equation was fitted to phantom and in vivo data, yielding estimates of {sup 15}O production and clearance rates, which were compared to live versus dead rates for the rabbit and to Monte Carlo predictions. Results: PET clearance rates agreed with decay constants of the dominant radionuclide species in 3 different phantom materials. In 2 oxygen-rich materials, the ratio of {sup 15}O production rates agreed with the expected ratio. In the dead rabbit thighs, the dynamic PET concentration histories were accurately described using {sup 15}O decay constant, whereas the live thigh activity decayed faster. Most importantly, the {sup 15}O production rates agreed within 2% (P>.5) between conditions. Conclusions: We developed a new method for quantitative measurement of {sup 15}O production and clearance rates in the period immediately following proton therapy. Measurements in the phantom and rabbits were well described in terms of {sup 15}O production and clearance rates, plus a correction for other isotopes. These proof-of-principle results support the feasibility of detailed verification of proton therapy treatment delivery. In addition, {sup 15}O clearance rates may be useful in monitoring permeability changes due to therapy.

  15. Experimental productivity rate optimization of rare earth element separation through preparative solid phase extraction chromatography.

    PubMed

    Knutson, Hans-Kristian; Max-Hansen, Mark; Jönsson, Christian; Borg, Niklas; Nilsson, Bernt

    2014-06-27

    Separating individual rare earth elements from a complex mixture with several elements is difficult and this is emphasized for the middle elements: Samarium, Europium and Gadolinium. In this study we have accomplished an overloaded one-step separation of these rare earth elements through preparative ion-exchange high-performance liquid chromatography with an bis (2-ethylhexyl) phosphoric acid impregnated column and nitric acid as eluent. An inductively coupled plasma mass spectrometry unit was used for post column element detection. The main focus was to optimize the productivity rate, subject to a yield requirement of 80% and a purity requirement of 99% for each element, by varying the flow rate and batch load size. The optimal productivity rate in this study was 1.32kgSamarium/(hmcolumn(3)), 0.38kgEuropium/(hmcolumn(3)) and 0.81kgGadolinium/(hmcolumn(3)). PMID:24835593

  16. Gluconic acid production by gad mutant of Klebsiella pneumoniae.

    PubMed

    Wang, Dexin; Wang, Chenhong; Wei, Dong; Shi, Jiping; Kim, Chul Ho; Jiang, Biao; Han, Zengsheng; Hao, Jian

    2016-08-01

    Klebsiella pneumoniae produces many economically important chemicals. Using glucose as a carbon source, the main metabolic product in K. pneumoniae is 2,3-butanediol. Gluconic acid is an intermediate of the glucose oxidation pathway. In the current study, a metabolic engineering strategy was used to develop a gluconic acid-producing K. pneumoniae strain. Deletion of gad, resulting in loss of gluconate dehydrogenase activity, led to the accumulation of gluconic acid in the culture broth. Gluconic acid accumulation by K. pneumoniae Δgad was an acid-dependent aerobic process, with accumulation observed at pH 5.5 or lower, and at higher levels of oxygen supplementation. Under all other conditions tested, 2,3-butanediol was the main metabolic product of the process. In fed batch fermentation, a final concentration of 422 g/L gluconic acid was produced by K. pneumoniae Δgad, and the conversion ratio of glucose to gluconic acid reached 1 g/g. The K. pneumoniae Δgad described in this study is the first genetically modified strain used for gluconic acid production, and this optimized method for gluconic acid production may have important industrial applications. Gluconic acid is an intermediate of this glucose oxidation pathway. Deletion of gad, resulting in loss of gluconate dehydrogenase activity, led to the accumulation of gluconic acid in the culture broth. In fed batch fermentation, a final concentration of 422 g/L gluconic acid was produced by the K. pneumoniae Δgad strain, and the conversion ratio of glucose to gluconic acid reached 1 g/g. PMID:27339313

  17. Recent advances in biological production of 3-hydroxypropionic acid.

    PubMed

    Kumar, Vinod; Ashok, Somasundar; Park, Sunghoon

    2013-11-01

    3-Hydroxypropionic acid (3-HP) is a valuable platform chemical that can be produced biologically from glucose or glycerol. This review article provides an overview and the current status of microbial 3-HP production. The constraints of microbial 3-HP production and possible solutions are also described. Finally, future prospects of biological 3-HP production are discussed. PMID:23473969

  18. Chicoric acid: chemistry, distribution, and production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Though chicoric acid was first identified in 1958, it was largely ignored until recent popular media coverage cited potential health beneficial properties from consuming food and dietary supplements containing this compound. To date, plants from at least 60 genera have been found to contain chicoric...

  19. The Separative Bioreactor: A Continuous Separation Process for the Simultaneous Production and Direct Capture of Organic Acids

    PubMed Central

    Arora, M. B.; Hestekin, J. A.; Snyder, S. W.; St. Martin, E. J.; Lin, Y. J.; Donnelly, M. I.; Millard, C. Sanville

    2007-01-01

    Abstract The replacement of petrochemicals with biobased chemicals requires efficient bioprocesses, biocatalysis, and product recovery. Biocatalysis (e.g., enzyme conversion and fermentation) offers an attractive alternative to chemical processing because biocatalysis utilize renewable feedstocks under benign reaction conditions. One class of chemical products that could be produced in large volumes by biocatalysis is organic acids. However, biocatalytic reactions to produce organic acids typically result in only dilute concentrations of the product because of product inhibition and acidification that drives the reaction pH outside of the optimal range for the biocatalyst. Buffering or neutralization results in formation of the acid salt rather than the acid, which requires further processing to recover the free acid product. To address these barriers to biocatalytic organic acid production, we developed the “separative bioreactor” based on resin wafer electrodeionization, which is an electro-deionization platform that uses resin wafers fabricated from ion exchange resins. The separative bioreactor simultaneously separates the organic acid from the biocatalyst as it is produced, thus it avoids product inhibition enhancing reaction rates. In addition, the separative bioreactor recovers the product in its acid form to avoid neutralization. The instantaneous separation of acid upon formation in the separative bioreactor is one of the first truly one-step systems for producing organic acids. The separative bioreactor was demonstrated with two systems. In the first demonstration, the enzyme glucose fructose oxidoreductase (GFOR) was immobilized in the reactor and later regenerated in situ. GFOR produced gluconic acid (in its acid form) continuously for 7 days with production rates up to 1000 mg/L/hr at >99% product recovery and GFOR reactivity >30mg gluconic acid/mg GFOR/hour. In the second demonstration, the E. coli strain CSM1 produced lactic acid for up to 24

  20. Low Phytic Acid Barley Responses to Phosphorus Rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Low phytic acid (LPA) barley (Hordeum vulgare L.) cultivars partition phosphorus in seed tissue differently than conventional barley cultivars through a reduction in seed phytic acid (myo-inositol-1,2,3,4,5,6-hexkisphosphate) coupled with an increase in inorganic phosphorus. The response of the LPA...

  1. Catalytic Conversion of Biomass for the Production of Hydrogen; Decomposition of Formic Acid

    NASA Astrophysics Data System (ADS)

    Azadi Manzour, Faraz

    Highly active bimetallic catalysts were synthesized and used for the decomposition of formic acid for the production of hydrogen. Ruthenium alloys were prepared and resulted in a maximum formic acid conversion of 68% (after one hour at 180 °C) and a turnover frequency of 0.7/s (at 5 wt% formic acid). The most promising catalysts were characterized by the means of X-ray diffraction and scanning electron microscopy. Kinetic studies were also carried out over these catalysts for the determination of reaction rate and turnover frequency. Promotion of Ru/C with tin, barium and cesium increased the formic acid conversion by 55%, 18% and 11% respectively.

  2. Kojic Acid Production from Agro-Industrial By-Products Using Fungi

    PubMed Central

    El-Kady, Ismael A.; Zohri, Abdel Naser A.; Hamed, Shimaa R.

    2014-01-01

    A total of 278 different isolates of filamentous fungi were screened using synthetic medium for respective ability to produce kojic acid. Nineteen, six, and five isolates proved to be low, moderate, and high kojic acid producers, respectively. Levels of kojic acid produced were generally increased when shaking cultivation was used rather than those obtained using static cultivation. A trial for the utilization of 15 agro-industrial wastes or by-products for kojic acid production by the five selected higher kojic acid producer isolates was made. The best by-product medium recorded was molasses for kojic acid. A. flavus numbers 7 and 24 were able to grow and produce kojic acid on only 12 out of 15 wastes or by-products media. The best medium used for kojic acid production by A. flavus number 7 was rice fragments followed by molasses, while the best medium used for kojic acid production by A. flavus number 24 was the molasses followed by orange, pea, and rice fragments. An attempt for production of kojic acid using a 1.5 L laboratory fermentor has been made. Aspergillus flavus number 7 was used and grown on molasses medium; maximum level (53.5 g/L) of kojic acid was obtained after eight days of incubation. PMID:24778881

  3. Biohydrogen and carboxylic acids production from wheat straw hydrolysate.

    PubMed

    Chandolias, Konstantinos; Pardaev, Sindor; Taherzadeh, Mohammad J

    2016-09-01

    Hydrolyzed wheat straw was converted into carboxylic acids and biohydrogen using digesting bacteria. The fermentations were carried out using both free and membrane-encased thermophilic bacteria (55°C) at various OLRs (4.42-17.95g COD/L.d), in semi-continuous conditions using one or two bioreactors in a series. The highest production of biohydrogen and acetic acid was achieved at an OLR of 4.42g COD/L.d, whilst the highest lactic acid production occurred at an OLR of 9.33g COD/L.d. Furthermore, the bioreactor with both free and membrane-encased cells produced 60% more lactic acid compared to the conventional, free-cell bioreactor. In addition, an increase of 121% and 100% in the production of acetic and isobutyric acid, respectively, was achieved in the 2nd-stage bioreactor compared to the 1st-stage bioreactor. PMID:27268482

  4. Mapping 15O production rate for proton therapy verification

    PubMed Central

    Grogg, Kira; Alpert, Nathaniel M.; Zhu, Xuping; Min, Chul Hee; Testa, Mauro; Winey, Brian; Normandin, Marc D.; Shih, Helen A.; Paganetti, Harald; Bortfeld, Thomas; El Fakhri, Georges

    2015-01-01

    Purpose This is a proof-of-principle study for the evaluation of 15O production as an imaging target, through the use of positron emission tomography (PET), to improve verification of proton treatment plans and study the effects of perfusion. Methods and Materials Dynamic PET measurements of irradiation-produced isotopes were taken for a phantom and rabbit thigh muscles. The rabbit muscle was irradiated and imaged in both live and dead conditions. A differential equation was fitted to the phantom and the in vivo data, yielding estimates of the 15O production and clearance rates, which was compared for live versus dead for the rabbit, and to Monte Carlo (MC) predictions. Results PET clearance rates agreed with the decay constants of the dominant radionuclide species in three different phantom materials. In two oxygen-rich materials, the ratio of 15O production rates agreed with the MC prediction. In the dead rabbit thighs, the dynamic PET concentration histories were accurately described using the 15O decay constant, while the live thigh activity decayed faster. Most importantly, the 15O production rates agreed within 2% (p> 0.5) between conditions. Conclusion We developed a new method for quantitative measurement of 15O production and clearance rates in the period immediately following proton therapy. Measurements in the phantom and rabbits were well described in terms of 15O production and clearance rates, plus a correction for other isotopes. These proof-of-principle results support the feasibility of detailed verification of proton therapy treatment delivery. In addition, 15O clearance rates may be useful in monitoring permeability changes due to therapy. PMID:25817530

  5. Glucose supplementation-induced changes in the Auxenochlorella protothecoides fatty acid composition suitable for biodiesel production.

    PubMed

    Krzemińska, Izabela; Oleszek, Marta

    2016-10-01

    This study evaluates the effect of different concentrations of glucose supplementation on growth, lipid accumulation, and the fatty acid profile in the Auxenochlorella protothecoides. Addition of glucose promoted the growth rate and decreased the chlorophyll content. Compared with photoautotrophic cells, an increase in the lipid content was observed in mixotrophic cells. The glucose addition induced changes in the fatty acid profile. Higher content of saturated fatty acids was found in the case of cells growing in the glucose-free medium. Oleic acid was the predominant component in mixotrophic cells supplemented with 5gL(-1) glucose, while linoleic acids dominated in cultures supplemented with both 1 and 3gL(-1) glucose. The use of glucose was associated with decreased levels of linolenic acid and PUFA. The changes in the fatty acid profile in mixotrophic cells are favourable for biodiesel production. PMID:27485282

  6. Very high gravity ethanol and fatty acid production of Zymomonas mobilis without amino acid and vitamin.

    PubMed

    Wang, Haoyong; Cao, Shangzhi; Wang, William Tianshuo; Wang, Kaven Tianyv; Jia, Xianhui

    2016-06-01

    Very high gravity (VHG) fermentation is the mainstream technology in ethanol industry, which requires the strains be resistant to multiple stresses such as high glucose concentration, high ethanol concentration, high temperature and harsh acidic conditions. To our knowledge, it was not reported previously that any ethanol-producing microbe showed a high performance in VHG fermentations without amino acid and vitamin. Here we demonstrate the engineering of a xylose utilizing recombinant Zymomonas mobilis for VHG ethanol fermentations. The recombinant strain can produce ethanol up to 136 g/L without amino acid and vitamin with a theoretical yield of 90 %, which is significantly superior to that produced by all the reported ethanol-producing strains. The intracellular fatty acids of the bacterial were about 16 % of the bacterial dry biomass, with the ratio of ethanol:fatty acids was about 273:1 (g/g). The recombinant strain was achieved by a multivariate-modular strategy tackles with the multiple stresses which are closely linked to the ethanol productivity of Z. mobilis. The over-expression of metB/yfdZ operon enabled the growth of the recombinant Z. mobilis in a chemically defined medium without amino acid and vitamin; and the fatty acids overproduction significantly increased ethanol tolerance and ethanol production. The coupled production of ethanol with fatty acids of the Z. mobilis without amino acid and vitamin under VHG fermentation conditions may permit a significant reduction of the production cost of ethanol and microbial fatty acids. PMID:27033536

  7. Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

    NASA Astrophysics Data System (ADS)

    Garland, Rebecca M.; Elrod, Matthew J.; Kincaid, Kristi; Beaver, Melinda R.; Jimenez, Jose L.; Tolbert, Margaret A.

    While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we use the aerodyne aerosol mass spectrometer (AMS) to probe the uptake of gas-phase hexanal into ammonium sulfate and sulfuric acid aerosols. While both deliquesced and dry non-acidic ammonium sulfate aerosols showed no organic uptake, the acidic aerosols took up substantial amounts of organic material when exposed to hexanal vapor. Further, we used 1H-NMR, Fourier transform infrared (FTIR) spectroscopy and GC-MS to identify the products of the acid-catalyzed reaction of hexanal in acidic aerosols. Both aldol condensation and hemiacetal products were identified, with the dominant reaction products dependent upon the initial acid concentration of the aerosol. The aldol condensation product was formed only at initial concentrations of 75-96 wt% sulfuric acid in water. The hemiacetal was produced at all sulfuric acid concentrations studied, 30-96 wt% sulfuric acid in water. Aerosols up to 88.4 wt% organic/11.1 wt% H 2SO 4/0.5 wt% water were produced via these two dimerization reaction pathways. The UV-VIS spectrum of the isolated aldol condensation product, 2-butyl 2-octenal, extends into the visible region, suggesting these reactions may impact aerosol optical properties as well as aerosol composition. In contrast to previous suggestions, no polymerization of hexanal or its products was observed at any sulfuric acid concentration studied, from 30 to 96 wt% in water.

  8. Biotechnological production of muconic acid: current status and future prospects.

    PubMed

    Xie, Neng-Zhong; Liang, Hong; Huang, Ri-Bo; Xu, Ping

    2014-01-01

    Muconic acid (MA), a high value-added bio-product with reactive dicarboxylic groups and conjugated double bonds, has garnered increasing interest owing to its potential applications in the manufacture of new functional resins, bio-plastics, food additives, agrochemicals, and pharmaceuticals. At the very least, MA can be used to produce commercially important bulk chemicals such as adipic acid, terephthalic acid and trimellitic acid. Recently, great progress has been made in the development of biotechnological routes for MA production. This present review provides a comprehensive and systematic overview of recent advances and challenges in biotechnological production of MA. Various biological methods are summarized and compared, and their constraints and possible solutions are also described. Finally, the future prospects are discussed with respect to the current state, challenges, and trends in this field, and the guidelines to develop high-performance microbial cell factories are also proposed for the MA production by systems metabolic engineering. PMID:24751381

  9. Genetic Engineering of Rhizopus for Enhancing Lactic Acid Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Rhizopus is frequently used to convert, or ferment sugars obtained from agricultural crops to lactic acid. This natural product has long been utilized by the food industry as an additive for preservation, flavor, and acidity. Additionally, it is used for the manufacture of environmental...

  10. Enhanced Production of Carboxylic Acids by Engineering of Rhizopus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The fungus Rhizopus is frequently used to convert, or ferment sugars obtained from agricultural crops to lactic acid. This natural product has long been utilized by the food industry as an additive for preservation, flavor, and acidity. Additionally, it is used for the manufacture of environmental...

  11. The effect of direct positron production on relativistic feedback rates

    NASA Astrophysics Data System (ADS)

    Vodopiyanov, I. B.; Dwyer, J. R.; Lucia, R. J.; Cramer, E. S.; Arabshahi, S.; Rassoul, H.

    2013-12-01

    Relativistic feedback produces a self-sustaining runaway electron discharge via the production of backward propagating positrons and back-scattered x-rays. To date, only positrons created from pair-production by gamma-rays interacting with the air have been considered. In contrast, direct pair-production involves the creation of electron-positron pairs directly from the interaction of energetic runaway electrons with nuclei, and so it does not require the generation of bremsstrahlung gamma-rays. For high electric fields, where the runaway electron avalanche length scales are short, pair-production involving bremsstrahlung gamma-rays makes a smaller contribution to the total relativistic feedback rates than at lower fields, since both the bremsstrahlung interaction and the pair-production need to occur over a short length. On the other hand, for high fields, because direct positron production only involves one interaction, it may make a significant contribution to relativistic feedback rates in some cases. In this poster, we shall present the direct positron production cross-sections and calculate the effects on the relativistic feedback rates due to this process.

  12. Improved growth, productivity and quality of tomato (Solanum lycopersicum L.) plants through application of shikimic acid

    PubMed Central

    Al-Amri, Salem M.

    2013-01-01

    A field experiment was conducted to investigate the effect of seed presoaking of shikimic acid (30, 60 and 120 ppm) on growth parameters, fruit productivity and quality, transpiration rate, photosynthetic pigments and some mineral nutrition contents of tomato plants. Shikimic acid at all concentrations significantly increased fresh and dry weights, fruit number, average fresh and dry fruit yield, vitamin C, lycopene, carotenoid contents, total acidity and fruit total soluble sugars of tomato plants when compared to control plants. Seed pretreatment with shikimic acid at various doses induces a significant increase in total leaf conductivity, transpiration rate and photosynthetic pigments (Chl. a, chl. b and carotenoids) of tomato plants. Furthermore, shikimic acid at various doses applied significantly increased the concentration of nitrogen, phosphorus and potassium in tomato leaves as compared to control non-treated tomato plants. Among all doses of shikimic acid treatment, it was found that 60 ppm treatment caused a marked increase in growth, fruit productivity and quality and most studied parameters of tomato plants when compared to other treatments. On the other hand, no significant differences were observed in total photosynthetic pigments, concentrations of nitrogen and potassium in leaves of tomato plants treated with 30 ppm of shikimic acid and control plants. According to these results, it could be suggested that shikimic acid used for seed soaking could be used for increasing growth, fruit productivity and quality of tomato plants growing under field conditions. PMID:24235870

  13. Effects of microbial utilization of phenolic acids and their phenolic acid breakdown products on allelopathic interactions

    SciTech Connect

    Blum, U.

    1998-04-01

    Reversible sorption of phenolic acids by soils may provide some protection to phenolic acids from microbial degradation. In the absence of microbes, reversible sorption 35 days after addition of 0.5--3 {micro}mol/g of ferulic acid or p-coumaric acid was 8--14% in Cecil A{sub p} horizon and 31--38% in Cecil B{sub t} horizon soil materials. The reversibly sorbed/solution ratios (r/s) for ferulic acid or p-coumaric acid ranged from 0.12 to 0.25 in A{sub p} and 0.65 to 0.85 in B{sub t} horizon soil materials. When microbes were introduced, the r/s ratio for both the A{sub p} and B{sub t} horizon soil materials increased over time up to 5 and 2, respectively, thereby indicating a more rapid utilization of solution phenolic acids over reversibly sorbed phenolic acids. The increase in r/s ratio and the overall microbial utilization of ferulic acid and/or p-coumaric acid were much more rapid in A{sub p} than in B{sub t} horizon soil materials. Reversible sorption, however, provided protection of phenolic acids from microbial utilization for only very short periods of time. Differential soil fixation, microbial production of benzoic acids (e.g., vanillic acid and p-hydroxybenzoic acid) from cinnamic acids (e.g., ferulic acid and p-coumaric acid, respectively), and the subsequent differential utilization of cinnamic and benzoic acids by soil microbes indicated that these processes can substantially influence the magnitude and duration of the phytotoxicity of individual phenolic acids.

  14. Increase of betulinic acid production in Saccharomyces cerevisiae by balancing fatty acids and betulinic acid forming pathways.

    PubMed

    Li, Jing; Zhang, Yansheng

    2014-04-01

    Betulinic acid is a plant-based triterpenoid that has been recognized for its antitumor and anti-HIV activities. The level of betulinic acid in its natural hosts is extremely low. In the present study, we constructed betulinic acid biosynthetic pathway in Saccharomyces cerevisiae by metabolic engineering. Given the betulinic acid forming pathways sharing the common substrate acetyl-CoA with fatty acid synthesis, the metabolic fluxes between the two pathways were varied by changing gene expressions, and their effects on betulinic acid production were investigated. We constructed nine S. cerevisiae strains representing nine combinations of the flux distributions between betulinic acid and fatty acid pathways. Our results demonstrated that it was possible to improve the betulinic acid production in S. cerevisiae while keeping a desirable growth phenotype by optimally balancing the carbon fluxes of the two pathways. Through modulating the expressions of the key genes on betulinic acid and fatty acid pathways, the difference in betulinic acid yield varied largely in the range of 0.01-1.92 mg L(-1) OD(-1). The metabolic engineering approach used in this study could be extended for synthesizing other triterpenoids in S. cerevisiae. PMID:24389702

  15. Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

    PubMed Central

    2011-01-01

    Background Solid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM), energy-dispersive x-ray spectrometry (EDX) and Brunauer, Emmett, and Teller (BET) method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated. Results The highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g) could be achieved. Conclusions The catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs. PMID:22145867

  16. Kinetics and Products of Heterogeneous Oxidation of Oleic acid, Linoleic acid and Linolenic acid in Aerosol Particles by Hydroxyl radicals

    NASA Astrophysics Data System (ADS)

    Nah, T.; Leone, S. R.; Wilson, K. R.

    2010-12-01

    A significant mass fraction of atmospheric aerosols is composed of a variety of oxidized organic compounds with varying functional groups that may affect the rate at which they chemically age. Here we study the heterogeneous reaction of OH radicals with different sub-micron, alkenoic acid particles: Oleic acid (OA), Linoleic acid (LA), and Linolenic acid (LNA), in the presence of H2O2 and O2. This research explores how OH addition reactions initiate chain reactions that rapidly transform the chemical composition of an organic particle. Particles are chemically aged in a photochemical flow tube reactor where they are exposed to OH radicals (~ 1011 molecule cm-3 s) that are produced by the photolysis of H2O2 at 254 nm. The aerosols are then sized and their composition analyzed via Atmospheric Pressure Chemical Ionization (APCI). Detailed kinetic measurements show that the reactive uptake coefficient is larger than 1, indicating the presence of secondary chemistry occurring in the condensed phase. Reactive uptake coefficient is found to scale linearly with the number of double bonds present in the molecule. In addition, the reactive uptake coefficient is found to depend sensitively upon the concentrations of O2 in the photochemical flow tube reactor, indicating that O2 plays a role in secondary chemistry. In the absence of O2 the reactive uptake coefficient increases to ~ 8, 5 and 3 for LNA, LA, and OA, respectively. The reactive uptake coefficient approaches values of 6, 4 and 2 for LNA, LA, and OA respectively when 18% of the total nitrogen flow is replaced with O2. Mechanistic pathways and products will also be presented herein.

  17. Cosmogenic Chlorine-36 Global Production Rate Parameter Calibration

    NASA Astrophysics Data System (ADS)

    Marrero, S.; Borchers, B.; Phillips, F. M.; Aumer, R.; Stone, J.

    2010-12-01

    As part of the CRONUS-Earth project, geological calibrations of in-situ production rates of cosmogenic nuclides, including chlorine-36, are being conducted as part of a larger project to improve the accuracy of techniques employing cosmogenic nuclides. Previous chlorine-36 production rate calibrations have been particularly difficult, likely due to the multiple production pathways. We are performing a step-wise calibration in order to specifically address the uncertainties and problems in previous studies. The low-energy neutrons will be constrained first using a depth profile analysis and then the spallation rates will be calibrated using surface and depth profile samples from five additional sites. This study will produce production rate parameters for each of the main spallation reactions (K, Ca) as well as the production by low-energy neutrons from Cl. Muons are based on Heisinger, 2002 and are not calibrated in this study. The geological calibration locations include the Peruvian Andes; Lake Bonneville, UT; Isle of Skye, Scotland; Hawaii; Dry Valleys of Antactica; and Copper Canyon, NM.

  18. 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...

  19. In vitro bile acid binding and short-chain fatty acid profile of flax fiber and ethanol co-products.

    PubMed

    Fodje, Adele M L; Chang, Peter R; Leterme, Pascal

    2009-10-01

    Fibers from flaxseed and co-products from ethanol production could be potential sources of dietary fiber in human diet. In vitro fermentation and bile acid binding models were used to investigate the metabolic effects of lignaMax (Bioriginal Food and Science Corp., Saskatoon, SK, Canada) flax meal, spent flax meal, soluble flax gum, wheat insoluble fiber (WIF), and rye insoluble fiber (RIF). Wheat and rye bran were used as reference samples. Bile acid binding of substrates was analysed at taurocholate ([(14)C]taurocholate) concentration of 12.5 mM. Soluble flax gum showed the highest bile acid binding (0.57 micromol/mg of fiber) (P acid binding between wheat bran (0.2 micromol/mg of fiber) and WIF (0.26 micromol/mg of fiber). RIF had higher (P acid binding (0.20 micromol/mg of fiber) than rye bran (0.13 micromol/mg of fiber). Substrates were hydrolyzed and incubated with pig fecal samples. Short-chain fatty acid (SCFA) profile and gas accumulation (G(f)) were compared. Soluble flax gum generated the highest amount of acetic and propionic acids. SCFA profiles of wheat/rye brans and WIF/RIF were similar (except for butyric acid). G(f) for soluble flax gum was greater (P < .001) than that of spent flax meal. G(f) values of the wheat samples were similar, whereas the G(f) of the rye bran was higher (P < .001) than that of RIF. Fractional degradation rate (micro(t = T/2)) (P < .001) was also recorded. The highest mu(t = T/2) was observed for the soluble flax gum. Oil-depleted flaxseed fractions and WIF/RIF (co-products from ethanol production) could be potential sources of dietary fiber in human nutrition. PMID:19857071

  20. Investigation of malic acid production in Aspergillus oryzae under nitrogen starvation conditions.

    PubMed

    Knuf, Christoph; Nookaew, Intawat; Brown, Stephen H; McCulloch, Michael; Berry, Alan; Nielsen, Jens

    2013-10-01

    Malic acid has great potential for replacing petrochemical building blocks in the future. For this application, high yields, rates, and titers are essential in order to sustain a viable biotechnological production process. Natural high-capacity malic acid producers like the malic acid producer Aspergillus flavus have so far been disqualified because of special growth requirements or the production of mycotoxins. As A. oryzae is a very close relative or even an ecotype of A. flavus, it is likely that its high malic acid production capabilities with a generally regarded as safe (GRAS) status may be combined with already existing large-scale fermentation experience. In order to verify the malic acid production potential, two wild-type strains, NRRL3485 and NRRL3488, were compared in shake flasks. As NRRL3488 showed a volumetric production rate twice as high as that of NRRL3485, this strain was selected for further investigation of the influence of two different nitrogen sources on malic acid secretion. The cultivation in lab-scale fermentors resulted in a higher final titer, 30.27 ± 1.05 g liter(-1), using peptone than the one of 22.27 ± 0.46 g liter(-1) obtained when ammonium was used. Through transcriptome analysis, a binding site similar to the one of the Saccharomyces cerevisiae yeast transcription factor Msn2/4 was identified in the upstream regions of glycolytic genes and the cytosolic malic acid production pathway from pyruvate via oxaloacetate to malate, which suggests that malic acid production is a stress response. Furthermore, the pyruvate carboxylase reaction was identified as a target for metabolic engineering, after it was confirmed to be transcriptionally regulated through the correlation of intracellular fluxes and transcriptional changes. PMID:23892740

  1. Investigation of Malic Acid Production in Aspergillus oryzae under Nitrogen Starvation Conditions

    PubMed Central

    Knuf, Christoph; Nookaew, Intawat; Brown, Stephen H.; McCulloch, Michael; Berry, Alan

    2013-01-01

    Malic acid has great potential for replacing petrochemical building blocks in the future. For this application, high yields, rates, and titers are essential in order to sustain a viable biotechnological production process. Natural high-capacity malic acid producers like the malic acid producer Aspergillus flavus have so far been disqualified because of special growth requirements or the production of mycotoxins. As A. oryzae is a very close relative or even an ecotype of A. flavus, it is likely that its high malic acid production capabilities with a generally regarded as safe (GRAS) status may be combined with already existing large-scale fermentation experience. In order to verify the malic acid production potential, two wild-type strains, NRRL3485 and NRRL3488, were compared in shake flasks. As NRRL3488 showed a volumetric production rate twice as high as that of NRRL3485, this strain was selected for further investigation of the influence of two different nitrogen sources on malic acid secretion. The cultivation in lab-scale fermentors resulted in a higher final titer, 30.27 ± 1.05 g liter−1, using peptone than the one of 22.27 ± 0.46 g liter−1 obtained when ammonium was used. Through transcriptome analysis, a binding site similar to the one of the Saccharomyces cerevisiae yeast transcription factor Msn2/4 was identified in the upstream regions of glycolytic genes and the cytosolic malic acid production pathway from pyruvate via oxaloacetate to malate, which suggests that malic acid production is a stress response. Furthermore, the pyruvate carboxylase reaction was identified as a target for metabolic engineering, after it was confirmed to be transcriptionally regulated through the correlation of intracellular fluxes and transcriptional changes. PMID:23892740

  2. Metabolic engineering of Aspergillus oryzae NRRL 3488 for increased production of L-malic acid.

    PubMed

    Brown, Stephen H; Bashkirova, Lena; Berka, Randy; Chandler, Tyler; Doty, Tammy; McCall, Keith; McCulloch, Michael; McFarland, Sarah; Thompson, Sheryl; Yaver, Debbie; Berry, Alan

    2013-10-01

    Malic acid, a petroleum-derived C4-dicarboxylic acid that is used in the food and beverage industries, is also produced by a number of microorganisms that follow a variety of metabolic routes. Several members of the genus Aspergillus utilize a two-step cytosolic pathway from pyruvate to malate known as the reductive tricarboxylic acid (rTCA) pathway. This simple and efficient pathway has a maximum theoretical yield of 2 mol malate/mol glucose when the starting pyruvate originates from glycolysis. Production of malic acid by Aspergillus oryzae NRRL 3488 was first improved by overexpression of a native C4-dicarboxylate transporter, leading to a greater than twofold increase in the rate of malate production. Overexpression of the native cytosolic alleles of pyruvate carboxylase and malate dehydrogenase, comprising the rTCA pathway, in conjunction with the transporter resulted in an additional 27 % increase in malate production rate. A strain overexpressing all three genes achieved a malate titer of 154 g/L in 164 h, corresponding to a production rate of 0.94 g/L/h, with an associated yield on glucose of 1.38 mol/mol (69 % of the theoretical maximum). This rate of malate production is the highest reported for any microbial system. PMID:23925533

  3. Role of dissolved oxygen availability on lactobionic acid production from whey by Pseudomonas taetrolens.

    PubMed

    Alonso, Saúl; Rendueles, Manuel; Díaz, Mario

    2012-04-01

    The influence of dissolved oxygen availability on cell growth and lactobionic acid production from whey by Pseudomonas taetrolens has been investigated for the first time. Results from pH-shift bioreactor cultivations have shown that high agitation rate schemes stimulated cell growth, increased pH-shift values and the oxygen uptake rate by cells, whereas lactobionic acid production was negatively affected. Conversely, higher aeration rates than 1.5 Lpm neither stimulated cell growth nor lactobionic acid production (22% lower for an aeration rate of 2 Lpm). Overall insights into bioprocess performance enabled the implementation of 350 rpm as the optimal agitation strategy during cultivation, which increased lactobionic productivity 1.2-fold (0.58-0.7 g/Lh) compared to that achieved at 1000 rpm. Oxygen supply has been shown to be a key bioprocess parameter for enhanced overall efficiency of the system, representing essential information for the implementation of lactobionic acid production at a large scale. PMID:22310213

  4. Bacterial production of free fatty acids from freshwater macroalgal cellulose

    PubMed Central

    Hoovers, Spencer W.; Marner, Wesley D.; Brownson, Amy K.; Lennen, Rebecca M.; Wittkopp, Tyler M.; Yoshitani, Jun; Zulkifly, Shahrizim; Graham, Linda E.; Chaston, Sheena D.; McMahon, Katherine D.

    2013-01-01

    The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing micro-organisms. Cellulose was extracted from an environmental sample of Cladophora glomerata-dominated periphyton that was collected from Lake Mendota, WI, USA. The resulting cellulose cake was hydrolyzed by commercial enzymes to release fermentable glucose. The hydrolysis mixture was used to formulate an undefined medium that was able to support the growth, without supplementation, of a free fatty acid (FFA)-overproducing strain of Escherichia coli (Lennen et. al 2010). To maximize free fatty acid production from glucose, an isopropyl β-D-1-thiogalactopyranoside (IPTG)-inducible vector was constructed to express the Umbellularia californica acyl–acyl carrier protein (ACP) thioesterase. Thioesterase expression was optimized by inducing cultures with 50 μM IPTG. Cell density and FFA titers from cultures grown on algae-based media reached 50% of those (~90 μg/mL FFA) cultures grown on rich Luria–Bertani broth supplemented with 0.2% glucose. In comparison, cultures grown in two media based on AFEX-pretreated corn stover generated tenfold less FFA than cultures grown in algae-based media. This study demonstrates that macroalgal cellulose is a potential carbon source for the production of biofuels or other microbially synthesized compounds. PMID:21643704

  5. Metabolic engineering of biocatalysts for carboxylic acids production

    PubMed Central

    Liu, Ping; Jarboe, Laura R.

    2012-01-01

    Fermentation of renewable feedstocks by microbes to produce sustainable fuels and chemicals has the potential to replace petrochemical-based production. For example, carboxylic acids produced by microbial fermentation can be used to generate primary building blocks of industrial chemicals by either enzymatic or chemical catalysis. In order to achieve the titer, yield and productivity values required for economically viable processes, the carboxylic acid-producing microbes need to be robust and well-performing. Traditional strain development methods based on mutagenesis have proven useful in the selection of desirable microbial behavior, such as robustness and carboxylic acid production. On the other hand, rationally-based metabolic engineering, like genetic manipulation for pathway design, has becoming increasingly important to this field and has been used for the production of several organic acids, such as succinic acid, malic acid and lactic acid. This review investigates recent works on Saccharomyces cerevisiae and Escherichia coli, as well as the strategies to improve tolerance towards these chemicals. PMID:24688671

  6. Lactic acid production by Enteroccocus faecium in liquefied sago starch

    PubMed Central

    2012-01-01

    Enterococcus faecium No. 78 (PNCM-BIOTECH 10375) isolated from puto, a type of fermented rice in the Philippines was used to produce lactic acid in repeated batch fermentation mode. Enzymatically liquefied sago starch was used as the sole carbon source, since sago (Metroxylon spp) is a sustainable crop for industrial exploitation. Liquefied sago starch was inoculated with E. faecium to perform the saccharification and fermentation processes simultaneously. Results demonstrated that E. faecium was reused for 11 fermentation cycles with an average lactic acid yield of 36.3 ± 4.71 g/l. The lactic acid production was superior to that of simple batch mode and continuous fermentation in terms of lactic acid concentration. An un-dissociated lactic acid concentration of 1.15 mM affected the productivity of the cells. Work is in progress to maintain and increase the usability of the cells over higher fermentation cycles. PMID:23021076

  7. Productivity of concentrated hyaluronic acid using a Maxblend fermentor.

    PubMed

    Hasegawa, S; Nagatsuru, M; Shibutani, M; Yamamoto, S; Hasebe, S

    1999-01-01

    Application of the Maxblend impeller to the fermentative production of hyaluronic acid (HA) was investigated. A 2-m3-scale fermentor fitted with this impeller (MBF) was used and the main fermentation was started with 85% of the nominal volume containing the pre-culture broth and medium. The kinetic characteristics of the MBF were compared with those of a conventional-type fermentor fitted with a turbine blade (TBN). The HA production yield in the MBF was over 20% higher than that in the TBN under the operating conditions of a high aeration rate and low vessel pressure since the broth viscosity increased. The apparent viscosity of the broth at the end of the cultivation rose to about 70 Pa.s. The molecular weight of the HA produced was independent of the agitation speed within the investigated range, and no significant difference was observed between the viscosity-average molecular weights of the HA obtained in the two types of fermentor, each having an estimated value of 4.3 x 10(6) under the same agitation power. PMID:16232576

  8. Variable rate lime application in Louisiana sugarcane production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture may offer sugarcane growers a management system that decreases costs and maximizes profits, while minimizing any potential negative environmental impact. The utility of variable-rate (VR) lime application in the initial production year (plant cane) of a 3-yr sugarcane crop cyc...

  9. RADIOLYTIC GAS PRODUCTION RATES OF POLYMERS EXPOSED TO TRITIUM GAS

    SciTech Connect

    Clark, E.

    2013-08-31

    Data from previous reports on studies of polymers exposed to tritium gas is further analyzed to estimate rates of radiolytic gas production. Also, graphs of gas release during tritium exposure from ultrahigh molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, a trade name is Teflon®), and Vespel® polyimide are re-plotted as moles of gas as a function of time, which is consistent with a later study of tritium effects on various formulations of the elastomer ethylene-propylene-diene monomer (EPDM). These gas production rate estimates may be useful while considering using these polymers in tritium processing systems. These rates are valid at least for the longest exposure times for each material, two years for UHMW-PE, PTFE, and Vespel®, and fourteen months for filled and unfilled EPDM. Note that the production “rate” for Vespel® is a quantity of H{sub 2} produced during a single exposure to tritium, independent of length of time. The larger production rate per unit mass for unfilled EPDM results from the lack of filler- the carbon black in filled EPDM does not produce H{sub 2} or HT. This is one aspect of how inert fillers reduce the effects of ionizing radiation on polymers.

  10. Asymptotics of Sample Entropy Production Rate for Stochastic Differential Equations

    NASA Astrophysics Data System (ADS)

    Wang, Feng-Yu; Xiong, Jie; Xu, Lihu

    2016-06-01

    Using the dimension-free Harnack inequality and the integration by parts formula for the associated diffusion semigroup, we prove the central limit theorem, the moderate deviation principle, and the logarithmic iteration law for the sample entropy production rate of a family of stochastic differential equations.

  11. Proceedings of a Workshop on Cosmogenic Nuclide Production Rates

    NASA Technical Reports Server (NTRS)

    Englert, Peter A. J. (Editor); Reedy, Robert C. (Editor); Michel, Rolf (Editor)

    1989-01-01

    Abstracts of reports from the proceedings are presented. The presentations were divided into discussion topics. The following general topic areas were used: (1) measured cosmogenic noble gas and radionuclide production rates in meteorite and planetary surface samples; (2) cross-section measurements and simulation experiments; and (3) interpretation of sample studies and simulation experiments.

  12. Aluminum: A neurotoxic product of acid rain

    SciTech Connect

    Martin, R.B.

    1994-07-01

    Two separate but converging concerns have resulted in an upsurge in research on aluminum ion in the past 15 years. Acid rain releases Al(III) from soils into fresh waters, where it is for the first time accessible to living organisms. Though long considered benign, Al(III) has recently been found to cause bone and neurological disorders, while its role in Alzheimer`s disease remains uncertain. The greater availability of Al(III), coupled with its demonstrated harmful effects, challenges chemists to describe its chemistry and biochemistry. Many interactions of Al(III) have been described, but several questions remain unsolved. A great deal of work not within the scope of this Account is described in several edited volumes. (This Account uses Al(III) as a generic term for the 3+ ion when a specific form is not indicated). 96 refs., 2 figs., 2 tabs.

  13. Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations

    PubMed Central

    Ylitervo, Päivi; Franzén, Carl Johan; Taherzadeh, Mohammad J.

    2014-01-01

    The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g·L−1 acetic acid at pH 5.0, at a dilution rate of 0.5 h−1. The cultivations were performed at both high (~25 g·L−1) and very high (100–200 g·L−1) yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g·L−1 sucrose, at volumetric rates of 5–6 g·L−1·h−1 at acetic acid concentrations up to 15.0 g·L−1. However, the yeast continued to produce ethanol also at a concentration of 20 g·L−1 acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials. PMID:25028956

  14. Biotechnology For hydroxy Fatty Acid Production in Oilseed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional source of hydroxyl fatty acid is from castor oil which contains 90% ricinoleate. Ricinoleate and its derivatives are used as raw materials for numerous industrial products, such as lubricants, plasticizers and bio-diesel. However, the production of castor oil is hampered by the presen...

  15. Membrane recovery of phenolic acid co-products from biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The technology to convert lignocellulosic biomass to biofuels is progressing with parallel efforts to develop processes to recover valuable natural products and generate additional revenue from these associated co-products. The lignified components of plant tissues contain phenolic acid structures s...

  16. Production of 3-hydroxypropionic acid from acrylic acid by newly isolated rhodococcus erythropolis LG12.

    PubMed

    Lee, Sang-Hyun; Park, Si Jae; Park, Oh-Jin; Cho, Junhyeong; Rhee, Joo Won

    2009-05-01

    A novel microorganism, designated as LG12, was isolated from soil based on its ability to use acrylic acid as the sole carbon source. An electron microscopic analysis of its morphological characteristics and phylogenetic classification by 16S rRNA homology showed that the LG12 strain belongs to Rhodococcus erythropolis. R. erythropolis LG12 was able to metabolize a high concentration of acrylic acid (up to 40 g/l). In addition, R. erythropolis LG12 exhibited the highest acrylic acid-degrading activity among the tested microorganisms, including R. rhodochrous, R. equi, R. rubber, Candida rugosa, and Bacillus cereus. The effect of the culture conditions of R. erythropolis LG12 on the production of 3-hydroxypropionic acid (3HP) from acrylic acid was also examined. To enhance the production of 3HP, acrylic acid-assimilating activity was induced by adding 1 mM acrylic acid to the culture medium when the cell density reached an OD600 of 5. Further cultivation of R. erythropolis LG12 with 40 g/l of acrylic acid resulted in the production of 17.5 g/l of 3HP with a molar conversion yield of 44% and productivity of 0.22 g/I/h at 30 degrees after 72 h. PMID:19494695

  17. ACID RECYCLING TO OPTIMIZE CITRIC ACID-MODIFIED SOYBEAN HULL PRODUCTION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were 1) to develop a wash procedure to remove non-reacted or residual citric acid after soybean hull modification in order to maximize the amount of non- reacted acid removed but minimize the subsequent effect on the product's ability to adsorb copper ion (Cu2+) and 2) t...

  18. 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

  19. Modulation of interleukin production by ascorbic acid.

    PubMed

    Schwager, J; Schulze, J

    1998-06-30

    We studied the influence of ascorbate (vitamin C) on peripheral blood mononuclear cells (PBMC) of pigs with hereditary deficiency in ascorbate synthesis. Groups of animals were depleted of, or supplemented with dietary ascorbate for up to 5 weeks. B lymphocytes and T lymphocyte subsets differed in the two experimental groups only marginally and transiently as determined by analysis of cell surface markers. The proliferative response of PBMC to B and T lymphocyte mitogens was lower in depleted as compared to supplemented animals. Interleukin (IL)-2 and IL-6 were determined by bioassays and were secreted within few hours after mitogenic activation of PBMC which contained normal physiological concentrations of ascorbate. IL-2 production peaked at about 24 h of in vitro culture after Con A activation, but it lasted for 2-3 days after PWM activation. The production of IL-2 and IL-6 were compared during systemic depletion and supplementation with ascorbate. Depleted PBMC produced IL-2 which accumulated in cultures instead of being rapidly consumed by IL-2 dependent cell growth. This suggests that cellular ascorbate influences the production of IL-2. Secretion of IL-6 by mitogen activated PBMC was also affected by prolonged dietary ascorbate depletion. The results suggest that ascorbate levels exert an early effect on immune homeostasis via reactive oxygen intermediates (ROI)-dependent expression of interleukin genes, since the transcription factor NF-kappa B is sensitive to ROI and regulates the expression of interleukin genes. PMID:9656430

  20. Improving succinic acid production by Actinobacillus succinogenes from raw industrial carob pods.

    PubMed

    Carvalho, Margarida; Roca, Christophe; Reis, Maria A M

    2016-10-01

    Carob pods are an inexpensive by-product of locust bean gum industry that can be used as renewable feedstock for bio-based succinic acid. Here, for the first time, unprocessed raw carob pods were used to extract a highly enriched sugar solution, afterwards used as substrate to produce succinic acid using Actinobacillus succinogenes. Batch fermentations containing 30g/L sugars resulted in a production rate of 1.67gSA/L.h and a yield of 0.39gSA/g sugars. Taking advantage of A. succinogenes' metabolism, uncoupling cell growth from succinic acid production, a fed-batch mode was implemented to increase succinic acid yield and reduce by-products formation. This strategy resulted in a succinic acid yield of 0.94gSA/g sugars, the highest yield reported in the literature for fed-batch and continuous experiments, while maintaining by-products at residual values. Results demonstrate that raw carob pods are a highly efficient feedstock for bio-based succinic acid production. PMID:27394995

  1. Biogas Production on Demand Regulated by Butyric Acid Addition

    NASA Astrophysics Data System (ADS)

    Kasper, K.; Schiffels, J.; Krafft, S.; Kuperjans, I.; Elbers, G.; Selmer, T.

    2016-03-01

    Investigating effects of volatile fatty acids on the biogas process it was observed that butyric acid can be used for transient stimulation of the methane production in biogas plants operating with low energy substrates like cattle manure. Upon addition of butyrate the methane output of the reactors doubled within 24 h and reached almost 3-times higher methane yields within 3-4 days. Butyrate was quantitatively eliminated and the reactors returned to the original productivity state within 3 days when application of butyrate was stopped. The opportunity to use butyrate feeding for increased biogas production on demand is discussed.

  2. Lactic Acid Production in a Mixed-Culture Biofilm Reactor †

    PubMed Central

    Demirci, Ali; Pometto, Anthony L.; Johnson, Kenneth E.

    1993-01-01

    Novel solid supports, consisting of polypropylene blended with various agricultural materials (pp composite), were evaluated as supports for pure- and mixed-culture continuous lactic acid fermentations in biofilm reactors. Streptomyces viridosporus T7A (ATCC 39115) was used to form a biofilm, and Lactobacillus casei subsp. rhamnosus (ATCC 11443) was used for lactic acid production. For mixed-culture fermentations, a 15-day continuous fermentation of S. viridosporus was performed initially to establish the biofilm. The culture medium was then inoculated with L. casei subsp. rhamnosus. For pure-culture fermentation, L. casei subsp. rhamnosus was inoculated directly into the reactors containing sterile pp composite chips. The biofilm reactors containing various pp composite chips were compared with a biofilm reactor containing pure polypropylene chips and with a reactor containing a suspension culture. Continuous fermentation was started, and each flow rate (0.06 to 1.92 ml/min) was held constant for 24 h; steady state was achieved after 10 h. Lactic acid production was determined throughout the 24-h period by high-performance liquid chromatography. Production rates that were two to five times faster than those of the suspension culture (control) were observed for the pure- and mixed-culture bioreactors. Both lactic acid production rates and lactic acid concentrations in the culture medium were consistently higher in mixed-culture than in pure-culture fermentations. Biofilm formation on the chips was detected at harvest by chip clumping and Gram staining. PMID:16348843

  3. Production and applications of rosmarinic acid and structurally related compounds.

    PubMed

    Kim, Gun-Dong; Park, Yong Seek; Jin, Young-Ho; Park, Cheung-Seog

    2015-03-01

    Rosmarinic acid (α-o-caffeoyl-3,4-dihydroxyphenyllactic acid; RA) is a naturally occurring hydroxylated compound commonly found in species of the subfamily Nepetoideae of the Lamiaceae and Boraginaceae, such as Rosmarinus officinalis, Salvia officinalis, and Perilla frutescens. RA is biosynthesized from the amino acids L-phenylalanine and L-tyrosine by eight enzymes that include phenylalanine ammonia lyase and cinnamic acid 4-hydroxylase. RA can also be chemically produced by the esterification of caffeic acid and 3,4-dihydroxyphenyllactic acid. RA and its numerous derivatives containing one or two RA with other aromatic moieties are well known and include lithospermic acid, yunnaneic acid, salvianolic acid, and melitric acid. Recently, RA and its derivatives have attracted interest for their biological activities, which include anti-inflammatory, anti-oxidant, anti-angiogenic, anti-tumor, and anti-microbial functions. Clinically, RA attenuates T cell receptor-mediated signaling, attenuates allergic diseases like allergic rhinitis and asthma, and 2,4-dinitrofluorobenzene-induced atopic dermatitis-like symptoms, protects from neurotoxicity, and slows the development of Alzheimer's disease. These attributes have increased the demand for the biotechnological production and application of RA and its derivatives. The present review discusses the function and application of RA and its derivatives including the molecular mechanisms underlying clinical efficacy. PMID:25620368

  4. Orthogonal Fatty Acid Biosynthetic Pathway Improves Fatty Acid Ethyl Ester Production in Saccharomyces cerevisiae.

    PubMed

    Eriksen, Dawn T; HamediRad, Mohammad; Yuan, Yongbo; Zhao, Huimin

    2015-07-17

    Fatty acid ethyl esters (FAEEs) are a form of biodiesel that can be microbially produced via a transesterification reaction of fatty acids with ethanol. The titer of microbially produced FAEEs can be greatly reduced by unbalanced metabolism and an insufficient supply of fatty acids, resulting in a commercially inviable process. Here, we report on a pathway engineering strategy in Saccharomyces cerevisiae for enhancing the titer of microbially produced FAEEs by providing the cells with an orthogonal route for fatty acid synthesis. The fatty acids generated from this heterologous pathway would supply the FAEE production, safeguarding endogenous fatty acids for cellular metabolism and growth. We investigated the heterologous expression of a Type-I fatty acid synthase (FAS) from Brevibacterium ammoniagenes coupled with WS/DGAT, the wax ester synthase/acyl-coenzyme that catalyzes the transesterification reaction with ethanol. Strains harboring the orthologous fatty acid synthesis yielded a 6.3-fold increase in FAEE titer compared to strains without the heterologous FAS. Variations in fatty acid chain length and degree of saturation can affect the quality of the biodiesel; therefore, we also investigated the diversity of the fatty acid production profile of FAS enzymes from other Actinomyces organisms. PMID:25594225

  5. Production rates of neon xenon isotopes by energetic neutrons

    NASA Technical Reports Server (NTRS)

    Leich, D. A.; Borg, R. J.; Lanier, V. B.

    1986-01-01

    As a first step in an experimental program to study the behavior of noble gases produced in situ in minerals, a suite of minerals and pure chemicals were irradiated with 14.5 MeV neutrons at LLNL's Rotating Target Neutron Source (RTNS-II) and production rates for noble gases were determined. While neutron effects in meteorites and lunar samples are dominated by low-energy neutron capture, more energetic cosmic-ray secondary neutrons can provide significant depth-dependent contributions to production of cosmogenic nuclides through endothermic reactions such as (n,2n), (n,np), (n,d) and (n,alpha). Production rates for nuclides produced by cosmic-ray secondary neutrons are therefore useful in interpreting shielding histories from the relative abundances of cosmogenic nuclides. Absolute production cross sections were calculated from isotope dilution analyses of NaCl, Mg, CsCl, and Ba(NO3)2 samples, assuming purity, stoichiometry, and quantitative noble gas retention and extraction. Relative production cross sections determined from neon isotopic ratios in the mineral samples were also considered in evaluating the neon production cross sections. Results are presented.

  6. Economical succinic acid production from cane molasses by Actinobacillus succinogenes.

    PubMed

    Liu, Yu-Peng; Zheng, Pu; Sun, Zhi-Hao; Ni, Ye; Dong, Jin-Jun; Zhu, Lei-Lei

    2008-04-01

    In this work, production of succinic acid by Actinobacillus succinogenes CGMCC1593 using cane molasses as a low cost carbon source was developed. In anaerobic bottles fermentation, succinic acid concentration of 50.6+/-0.9 g l(-1) was attained at 60 h using an optimum medium containing molasses pretreated with sulfuric acid, resulting in a succinic acid yield of 79.5+/-1.1% and sugar utilization of 97.1+/-0.6%. When batch fermentation was carried out in a 5-l stirred bioreactor with pretreated molasses, 46.4 g l(-1) of succinic acid was attained at 48 h and faster cells growth was also observed. Fed batch fermentation was performed to minimize the substrate (sugar) inhibition effect, giving 55.2 g l(-1) of succinic acid and 1.15 g l(-1)h(-1) of productivity at 48 h. The present study suggests that the inexpensive cane molasses could be utilized for the economical and efficient production of succinic acid by A. succinogenes. PMID:17532626

  7. Updates on industrial production of amino acids using Corynebacterium glutamicum.

    PubMed

    Wendisch, Volker F; Jorge, João M P; Pérez-García, Fernando; Sgobba, Elvira

    2016-06-01

    L-Amino acids find various applications in biotechnology. L-Glutamic acid and its salts are used as flavor enhancers. Other L-amino acids are used as food or feed additives, in parenteral nutrition or as building blocks for the chemical and pharmaceutical industries. L-amino acids are synthesized from precursors of central carbon metabolism. Based on the knowledge of the biochemical pathways microbial fermentation processes of food, feed and pharma amino acids have been developed. Production strains of Corynebacterium glutamicum, which has been used safely for more than 50 years in food biotechnology, and Escherichia coli are constantly improved using metabolic engineering approaches. Research towards new processes is ongoing. Fermentative production of L-amino acids in the million-ton-scale has shaped modern biotechnology and its markets continue to grow steadily. This review focusses on recent achievements in strain development for amino acid production including the use of CRISPRi/dCas9, genome-reduced strains, biosensors and synthetic pathways to enable utilization of alternative carbon sources. PMID:27116971

  8. Water evaporation rates across hydrophobic acid monolayers at equilibrium spreading pressure.

    PubMed

    Tsuji, Minami; Nakahara, Hiromichi; Moroi, Yoshikiyo; Shibata, Osamu

    2008-02-15

    The effect of alkanoic acid [CH(3)(CH(2))(n-2)COOH; HCn] and perfluoroalkanoic acid [CF(3)(CF(2))(n-2)COOH; FCn] monolayers on the water evaporation rate was investigated by thermogravimetry tracing the decrease in amount of water with time. The evaporation rate from the surface covered by a monolayer was measured as a function of temperature and hydrophobic chain length of the acids, where the monolayer was under an equilibrium spreading pressure. From thermal behavior of the crystallized acids, their solid states are C-type in crystalline state over the temperature range from 298.2 to 323.2 K. The dry air was flowed through a furnace tube of a thermogravimetry apparatus at the flow rate of 80 mL min(-1), where the evaporation rate becomes almost constant irrespective of the flow rate. The temperature dependence of the evaporation rate was analyzed kinetically to evaluate the activation energy and thermodynamics values for the activated complex, which demonstrated that these values were almost the same for both alkanoic acids and perfluoroalkanoic acids, although the effect of perfluoroalkanoic acids on the evaporation rate was smaller than that of corresponding hydrogenated fatty acids. The difference in the evaporation rate between FCn and HCn was examined by atomic force microscopy (AFM), Brewster angle microscopy (BAM), surface potential (DeltaV) at equilibrium spreading pressure, and Langmuir curve (pi-A isotherm), and their results were consistent and supported the difference. PMID:18048050

  9. Relationship between the electrochemical activity of Raney nickel and the rate of hydrogenation of maleic acid

    SciTech Connect

    Pervii, E.N.; Sofronkov, A.N.; Fedyshina, N.M.

    1986-02-10

    The purpose of this investigation was to determine the conditions in which a direct correlation exists between the rate of hydrogenation of maleic acid and the electrochemical activity of catalysts of hydrogen ionization. The rate of maleic acid hydrogenation in presence of Raney nickel catalyst was studied by a combination of volumetric and potentiometric methods.

  10. The production of ω-hydroxy palmitic acid using fatty acid metabolism and cofactor optimization in Escherichia coli.

    PubMed

    Sung, Changmin; Jung, Eunok; Choi, Kwon-Young; Bae, Jin-Hyung; Kim, Minsuk; Kim, Joonwon; Kim, Eun-Jung; Kim, Pyoung Il; Kim, Byung-Gee

    2015-08-01

    Hydroxylated fatty acids (HFAs) are used as important precursors for bulk and fine chemicals in the chemical industry. Here, to overproduce long-chain (C16-C18) fatty acids and hydroxy fatty acid, their biosynthetic pathways including thioesterase (Lreu_0335) from Lactobacillus reuteri DSM20016, β-hydroxyacyl-ACP dehydratase (fabZ) from Escherichia coli, and a P450 system (i.e., CYP153A from Marinobacter aquaeolei VT8 and camA/camB from Pseudomonas putida ATCC17453) were overexpressed. Acyl-CoA synthase (fadD) involved in fatty acid degradation by β-oxidation was also deleted in E. coli BW25113. The engineered E. coli FFA4 strain without the P450 system could produce 503.0 mg/l of palmitic (C16) and 508.4 mg/l of stearic (C18) acids, of which the amounts are ca. 1.6- and 2.3-fold higher than those of the wild type. On the other hand, the E. coli HFA4 strain including the P450 system for ω-hydroxylation could produce 211.7 mg/l of ω-hydroxy palmitic acid, which was 42.1 ± 0.1 % of the generated palmitic acid, indicating that the hydroxylation reaction was the rate-determining step for the HFA production. For the maximum production of ω-hydroxy palmitic acid, NADH, i.e., an essential cofactor for P450 reaction, was overproduced by the integration of NAD(+)-dependent formate dehydrogenase (FDH) from Candida boidinii into E. coli chromosome and the deletion of alcohol dehydrogenase (ADH). Finally, the NADH-level-optimized E. coli strain produced 610 mg/l of ω-hydroxy palmitic acid (ω-HPA), which was almost a threefold increase in its yield compared to the same strain without NADH overproduction. PMID:25957153

  11. Utilization of by-products derived from bioethanol production process for cost-effective production of lactic acid.

    PubMed

    Moon, Se-Kwon; Wee, Young-Jung; Choi, Gi-Wook

    2014-10-01

    The by-products of bioethanol production such as thin stillage (TS) and condensed distillers solubles (CDS) were used as a potential nitrogen source for economical production of lactic acid. The effect of those by-products and their concentrations on lactic acid fermentation were investigated using Lactobacillus paracasei CHB2121. Approximately, 6.7 g/L of yeast extract at a carbon source to nitrogen source ratio of 15 was required to produce 90 g/L of lactic acid in the medium containing 100 g/L of glucose. Batch fermentation of TS medium resulted in 90 g/L of lactic acid after 48 h, and the medium containing 10 % CDS resulted in 95 g/L of lactic acid after 44 h. Therefore, TS and CDS could be considered as potential alternative fermentation medium for the economical production of lactic acid. Furthermore, lactic acid fermentation was performed using only cassava and CDS for commercial production of lactic acid. The volumetric productivity of lactic acid [2.94 g/(L·h)] was 37 % higher than the productivity obtained from the medium with glucose and CDS. PMID:25163666

  12. A comparative evaluation of different types of microbial electrolysis desalination cells for malic acid production.

    PubMed

    Liu, Guangli; Zhou, Ying; Luo, Haiping; Cheng, Xing; Zhang, Renduo; Teng, Wenkai

    2015-12-01

    The aim of this study was to investigate different microbial electrolysis desalination cells for malic acid production. The systems included microbial electrolysis desalination and chemical-production cell (MEDCC), microbial electrolysis desalination cell (MEDC) with bipolar membrane and anion exchange membrane (BP-A MEDC), MEDC with bipolar membrane and cation exchange membrane (BP-C MEDC), and modified microbial desalination cell (M-MDC). The microbial electrolysis desalination cells performed differently in terms of malic acid production and energy consumption. The MEDCC performed best with the highest malic acid production rate (18.4 ± 0.6 mmol/Lh) and the lowest energy consumption (0.35 ± 0.14 kWh/kg). The best performance of MEDCC was attributable to the neutral pH condition in the anode chamber, the lowest internal resistance, and the highest Geobacter percentage of the anode biofilm population among all the reactors. PMID:26367771

  13. Automated Production of High Rep Rate Foam Targets

    NASA Astrophysics Data System (ADS)

    Hall, F.; Spindloe, C.; Haddock, D.; Tolley, M.; Nazarov, W.

    2016-04-01

    Manufacturing low density targets in the numbers needed for high rep rate experiments is highly challenging. This report summarises advances from manual production to semiautomated and the improvements that follow both in terms of production time and target uniformity. The production process is described and shown to be improved by the integration of an xyz robot with dispensing capabilities. Results are obtained from manual and semiautomated production runs and compared. The variance in the foam thickness is reduced significantly which should decrease experimental variation due to target parameters and could allow for whole batches to be characterised by the measurement of a few samples. The work applies to both foil backed and free standing foam targets.

  14. The effect of linoleic acid on the whole body synthesis rates of polyunsaturated fatty acids from α-linolenic acid and linoleic acid in free-living rats.

    PubMed

    Domenichiello, Anthony F; Kitson, Alex P; Chen, Chuck T; Trépanier, Marc-Olivier; Stavro, P Mark; Bazinet, Richard P

    2016-04-01

    Docosahexaenoic acid (DHA) is thought to be important for brain function. The main dietary source of DHA is fish, however, DHA can also be synthesized from precursor omega-3 polyunsaturated fatty acids (n-3 PUFA), the most abundantly consumed being α-linolenic acid (ALA). The enzymes required to synthesize DHA from ALA are also used to synthesize longer chain omega-6 (n-6) PUFA from linoleic acid (LNA). The large increase in LNA consumption that has occurred over the last century has led to concern that LNA and other n-6 PUFA outcompete n-3 PUFA for enzymes involved in DHA synthesis, and therefore, decrease overall DHA synthesis. To assess this, rats were fed diets containing LNA at 53 (high LNA diet), 11 (medium LNA diet) or 1.5% (low LNA diet) of the fatty acids with ALA being constant across all diets (approximately 4% of the fatty acids). Rats were maintained on these diets from weaning for 8 weeks, at which point they were subjected to a steady-state infusion of labeled ALA and LNA to measure DHA and arachidonic acid (ARA) synthesis rates. DHA and ARA synthesis rates were generally highest in rats fed the medium and high LNA diets, while the plasma half-life of DHA was longer in rats fed the low LNA diet. Therefore, increasing dietary LNA, in rats, did not impair DHA synthesis; however, low dietary LNA led to a decrease in DHA synthesis with tissue concentrations of DHA possibly being maintained by a longer DHA half-life. PMID:27012633

  15. Measurement of the rates of oxindole-3-acetic acid turnover, and indole-3-acetic acid oxidation in Zea mays seedlings

    NASA Technical Reports Server (NTRS)

    Nonhebel, H. M.; Bandurski, R. S. (Principal Investigator)

    1986-01-01

    Oxindole-3-acetic acid is the principal catabolite of indole-3-acetic acid in Zea mays seedlings. In this paper measurements of the turnover of oxindole-3-acetic acid are presented and used to calculate the rate of indole-3-acetic acid oxidation. [3H]Oxindole-3-acetic acid was applied to the endosperm of Zea mays seedlings and allowed to equilibrate for 24 h before the start of the experiment. The subsequent decrease in its specific activity was used to calculate the turnover rate. The average half-life of oxindole-3-acetic acid in the shoots was found to be 30 h while that in the kernels had an average half-life of 35h. Using previously published values of the pool sizes of oxindole-3-acetic acid in shoots and kernels from seedlings of the same age and variety, and grown under the same conditions, the rate of indole-3-acetic acid oxidation was calculated to be 1.1 pmol plant-1 h-1 in the shoots and 7.1 pmol plant-1 h-1 in the kernels.

  16. Integrated production of cellulosic bioethanol and succinic acid from industrial hemp in a biorefinery concept.

    PubMed

    Kuglarz, Mariusz; Alvarado-Morales, Merlin; Karakashev, Dimitar; Angelidaki, Irini

    2016-01-01

    The aim of this study was to develop integrated biofuel (cellulosic bioethanol) and biochemical (succinic acid) production from industrial hemp (Cannabis sativa L.) in a biorefinery concept. Two types of pretreatments were studied (dilute-acid and alkaline oxidative method). High cellulose recovery (>95%) as well as significant hemicelluloses solubilization (49-59%) after acid-based method and lignin solubilization (35-41%) after alkaline H2O2 method were registered. Alkaline pretreatment showed to be superior over the acid-based method with respect to the rate of enzymatic hydrolysis and ethanol productivity. With respect to succinic acid production, the highest productivity was obtained after liquid fraction fermentation originated from steam treatment with 1.5% of acid. The mass balance calculations clearly showed that 149kg of EtOH and 115kg of succinic acid can be obtained per 1ton of dry hemp. Results obtained in this study clearly document the potential of industrial hemp for a biorefinery. PMID:26551652

  17. The effect of organic acids on plagioclase dissolution rates and stoichiometry

    NASA Astrophysics Data System (ADS)

    Welch, Susan A.; Ullman, William J.

    1993-06-01

    The rates of plagioclase dissolution in solutions containing organic acids are up to ten times greater than the rates determined in solutions containing inorganic acids at the same acidity. Initial rates of dissolution are poorly reproduced in replicate experiments. After a day, however, the rates of plagioclase dissolution calculated from the rates of silicon release are reproducible and constant for up to nineteen days. Steady-state rates of dissolution are highest (up to 1.3 × 10 -8 mol/m 2/sec) in acidic solutions (pH ≈ 3) and decrease (to 1 × 10 -11 mol/m 2/sec) as acidity decreases toward neutral pH. The polyfunctional acids, oxalate, citrate, succinate, pyruvate, and 2-ketoglutarate, are the most effective at promoting dissolution. Acetate and propionate are not as effective as the other organic acids but are nonetheless more effective than solutions containing only inorganic acids. The degree of ligand-promoted enhancement of dissolution rate (rate in organic-containing solution/rate in inorganic solution at the same pH) decreases as acidity increases, indicating that the ligand-promoted dissolution mechanism becomes relatively more important as the rate of proton-promoted dissolution decreases. The stoichiometry of release to solution indicates that dissolution is selective even after the rates of dissolution become constant. As in previously published studies, Na and Ca are rapidly released from the plagioclase feldspar, leaving a surface enriched in Si and/or Al. The ratio of Al/Si released to solution indicates that the stoichiometry of the residual plagioclase surface is a function of pH and the nature of the organic ligand. The ligands which remove Al in preference to Si from the dissolving mineral surface are also those which enhance overall plagioclase dissolution rates.

  18. Photoautotrophic production of D-lactic acid in an engineered cyanobacterium

    PubMed Central

    2013-01-01

    Background The world faces the challenge to develop sustainable technologies to replace thousands of products that have been generated from fossil fuels. Microbial cell factories serve as promising alternatives for the production of diverse commodity chemicals and biofuels from renewable resources. For example, polylactic acid (PLA) with its biodegradable properties is a sustainable, environmentally friendly alternative to polyethylene. At present, PLA microbial production is mainly dependent on food crops such as corn and sugarcane. Moreover, optically pure isomers of lactic acid are required for the production of PLA, where D-lactic acid controls the thermochemical and physical properties of PLA. Henceforth, production of D-lactic acid through a more sustainable source (CO2) is desirable. Results We have performed metabolic engineering on Synechocystis sp. PCC 6803 for the phototrophic synthesis of optically pure D-lactic acid from CO2. Synthesis of optically pure D-lactic acid was achieved by utilizing a recently discovered enzyme (i.e., a mutated glycerol dehydrogenase, GlyDH*). Significant improvements in D-lactic acid synthesis were achieved through codon optimization and by balancing the cofactor (NADH) availability through the heterologous expression of a soluble transhydrogenase. We have also discovered that addition of acetate to the cultures improved lactic acid production. More interestingly, 13C-pathway analysis revealed that acetate was not used for the synthesis of lactic acid, but was mainly used for synthesis of certain biomass building blocks (such as leucine and glutamate). Finally, the optimal strain was able to accumulate 1.14 g/L (photoautotrophic condition) and 2.17 g/L (phototrophic condition with acetate) of D-lactate in 24 days. Conclusions We have demonstrated the photoautotrophic production of D-lactic acid by engineering a cyanobacterium Synechocystis 6803. The engineered strain shows an excellent D-lactic acid productivity from CO2. In

  19. Factors affecting production rates of cosmogenic nuclides in extraterrestrial matter

    NASA Astrophysics Data System (ADS)

    Reedy, R. C.

    2015-10-01

    Good production rates are needed for cosmic-ray-produced nuclides to interpret their measurements. Rates depend on many factors, especially the pre-atmospheric object's size, the location of the sample in that object (such as near surface or deep inside), and the object's bulk composition. The bulk composition affects rates, especially in objects with very low and very high iron contents. Extraterrestrial materials with high iron contents usually have higher rates for making nuclides made by reactions with energetic particles and lower rates for the capture of thermal neutrons. In small objects and near the surface of objects, the cascade of secondary neutrons is being developed as primary particles are being removed. Deep in large objects, that secondary cascade is fully developed and the fluxes of primary particles are low. Recent work shows that even the shape of an object in space has a small but measureable effect. Work has been done and continues to be done on better understanding those and other factors. More good sets of measurements in meteorites with known exposure geometries in space are needed. With the use of modern Monte Carlo codes for the production and transport of particles, the nature of these effects have been and is being studied. Work needs to be done to improve the results of these calculations, especially the cross sections for making spallogenic nuclides.

  20. Fatty acid composition of Swedish bakery products, with emphasis on trans-fatty acids.

    PubMed

    Trattner, Sofia; Becker, Wulf; Wretling, Sören; Öhrvik, Veronica; Mattisson, Irene

    2015-05-15

    Trans-fatty acids (TFA) have been associated with increased risk of coronary heart disease, by affecting blood lipids and inflammation factors. Current nutrition recommendations emphasise a limitation of dietary TFA intake. The aim of this study was to investigate fatty acid composition in sweet bakery products, with emphasis on TFA, on the Swedish market and compare fatty acid composition over time. Products were sampled in 2001, 2006 and 2007 and analysed for fatty acid composition by using GC. Mean TFA levels were 0.7% in 2007 and 5.9% in 2001 of total fatty acids. In 1995-97, mean TFA level was 14.3%. In 2007, 3 of 41 products had TFA levels above 2% of total fatty acids. TFA content had decreased in this product category, while the proportion of saturated (SFA) and polyunsaturated (PUFA) fatty acids had increased, mostly through increased levels of 16:0 and 18:2 n-6, respectively. The total fat content remained largely unchanged. PMID:25577101

  1. Phenoloxidase production and vanillic acid metabolism by Zygomycetes.

    PubMed

    Seigle-Murandi, F; Guiraud, P; Steiman, R; Benoit-Guyod, J L

    1992-04-01

    The ability of 23 strains of Zygomycetes to produce extracellular phenoloxidases was examined on solid media by using 10 different reagents. The results varied depending on the reagent and indicated that most of the strains were devoid of phenoloxidase activity. The production of inducible phenoloxidases was demonstrated by the Bavendamm reaction. The study of the biotransformation of vanillic acid in synthetic medium indicated that the reaction most often obtained was the reduction of vanillic acid to vanillyl alcohol. Helicostylum piriforme and Rhizopus microsporus var. chinensis completely metabolized vanillic acid while good transformation was obtained with Absidia spinosa, Cunninghamella bainieri, Mucor bacilliformis, Mucor plumbeus, Rhizopus arrhizus, Rhizopus stolonifer, Syncephalastrum racemosum and Zygorhynchus moelleri. Other strains did not degrade or poorly degraded vanillic acid. Decarboxylation and demethoxylation of this compound was independent of the production of phenoloxidases as in the case of white-rot fungi. Other enzymatic systems might be implicated in this phenomenon. PMID:1602986

  2. Production rate calculations for a secondary beam facility

    SciTech Connect

    Jiang, C.L.; Back, B.B.; Rehm, K.E.

    1995-08-01

    In order to select the most cost-effective method for the production of secondary ion beams, yield calculations for a variety of primary beams were performed ranging in mass from protons to {sup 18}O with energies of 100-200 MeV/u. For comparison, production yields for 600-1000 MeV protons were also calculated. For light ion-(A < {sup 4}He) induced reactions at energies above 50 MeV/u the LAHET code was used while the low energy calculations were performed with LPACE. Heavy-ion-induced production rates were calculated with the ISAPACE program. The results of these codes were checked against each other and wherever possible a comparison with experimental data was performed. These comparisons extended to very exotic reaction channels, such as the production of {sup 100}Sn from {sup 112}Sn and {sup 124}Xe induced fragmentation reactions. These comparisons indicate that the codes are able to predict production rates to within one order of magnitude.

  3. Entropy production rate as a constraint for collisionless fluid closures

    SciTech Connect

    Fleurence, E.; Sarazin, Y.; Garbet, X.; Dif-Pradalier, G.; Ghendrih, Ph.; Grandgirard, V.; Ottaviani, M.

    2006-11-30

    A novel method is proposed to construct collisionless fluid closures accounting for some kinetic properties. The first dropped fluid moment is assumed to be a linear function of the lower order ones. Optimizing the agreement between the fluid and kinetic entropy production rates is used to constrain the coefficients of the linear development. This procedure is applied to a reduced version of the interchange instability. The closure, involving the absolute value of the wave vector, is non-local in real space. In this case, the linear instability thresholds are the same, and the linear growth rates exhibit similar characteristics. Such a method is applicable to other models and classes of instabilities.

  4. Eigenvalue methods for unimolecular rate calculations with several products.

    PubMed

    Pritchard, Huw O

    2007-10-25

    When the calculation of a unimolecular reaction rate constant is cast in the form of a master equation eigenvalue problem, the magnitude of that rate is often smaller than the rounding error of the trace of the corresponding reaction matrix. Here, a previously published procedure (Pritchard, H. O. J. Phys. Chem. A 2004, 108, 5249-5252) for solving this problem is extended to the case of more than one reaction product. An Appendix notes the occurrence of avoided crossings between eigenvalues of the master equation in reversible, in mixed reversible-irreversible, and in multiwell unimolecular reaction calculations. PMID:17914776

  5. Materials and methods for efficient lactic acid production

    DOEpatents

    Zhou, Shengde; Ingram, Lonnie O'Neal; Shanmugam, Keelnatham T.; Yomano, Lorraine; Grabar, Tammy B.; Moore, Jonathan C.

    2009-12-08

    The present invention provides derivatives of ethanologenic Escherichia coli K011 constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.

  6. Materials and methods for efficient lactic acid production

    SciTech Connect

    Zhou, Shengde; Ingram, Lonnie O'Neal; Shanmugam, Keelnatham T; Yomano, Lorraine; Grabar, Tammy B; Moore, Jonathan C

    2013-04-23

    The present invention provides derivatives of Escherichia coli constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.

  7. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway

    PubMed Central

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z.; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  8. Engineered Production of Short Chain Fatty Acid in Escherichia coli Using Fatty Acid Synthesis Pathway.

    PubMed

    Jawed, Kamran; Mattam, Anu Jose; Fatma, Zia; Wajid, Saima; Abdin, Malik Z; Yazdani, Syed Shams

    2016-01-01

    Short-chain fatty acids (SCFAs), such as butyric acid, have a broad range of applications in chemical and fuel industries. Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of SCFAs. In this study we compared three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron, for production of SCFAs in Escherichia coli utilizing native fatty acid synthesis (FASII) pathway and modulated the genetic and bioprocess parameters to improve its yield and productivity. E. coli strain expressing tesBT gene yielded maximum butyric acid titer at 1.46 g L-1, followed by tesBF at 0.85 g L-1 and tesAT at 0.12 g L-1. The titer of butyric acid varied significantly depending upon the plasmid copy number and strain genotype. The modulation of genetic factors that are known to influence long chain fatty acid production, such as deletion of the fadD and fadE that initiates the fatty acid degradation cycle and overexpression of fadR that is a global transcriptional activator of fatty acid biosynthesis and repressor of degradation cycle, did not improve the butyric acid titer significantly. Use of chemical inhibitor cerulenin, which restricts the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay indicated that cerulenin also inhibited short chain specific thioesterase, though inhibitory concentration varied according to the type of thioesterase used. Further process optimization followed by fed-batch cultivation under phosphorous limited condition led to production of 14.3 g L-1 butyric acid and 17.5 g L-1 total free fatty acid at 28% of theoretical yield. This study expands our understanding of SCFAs production in E. coli through FASII pathway and highlights role of genetic and process optimization to enhance the desired product. PMID:27466817

  9. 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

  10. Study of acetic acid production by immobilized acetobacter cells: oxygen transfer

    SciTech Connect

    Ghommidh, C.; Navarro, J.M.; Durand, G.

    1982-03-01

    The immobilization of living Acetobacter cells by adsorption onto a large-surface-area ceramic support was studied in a pulsed flow reactor. The high oxygen transfer capability of the reactor enabled acetic acid production rates up to 10.4 g/L/h to be achieved. Using a simple mathematical model incorporating both internal and external mass transfer coefficients, it was shown that oxygen transfer in the microbial film controls the reactor productivity. (Refs. 10).

  11. Dissolution rates of carbonated hydroxyapatite in hydrochloric acid.

    PubMed

    Hankermeyer, Christine R; Ohashi, Kevin L; Delaney, David C; Ross, John; Constantz, Brent R

    2002-02-01

    Osteoclasts have been shown to dissolve efficiently and effectively the mineral phase of bone by locally controlling the environment surrounding the cell. Although this mineral phase has been identified and well characterized as carbonated hydroxyapatite, there is little understanding of the factors that affect the dissolution properties of this mineral phase. Mimicking the mechanism by which osteoclasts dissolve the mineral phase of bone may provide insight into methods for the decalcification of atherosclerotic mineral deposits in the vascular system. Accordingly, a detailed characterization of the effects of various chemical and mechanical parameters on the dissolution of carbonated hydroxyapatite mineral was investigated in this study. Increases in the mineral dissolution rate (2-10 times) were associated with increases in dissolving solution [H+], osmolality, temperature, and flow rate. Mineral dissolution rate increases (5-8 times) were associated with greater surface area of the mineral and mechanical agitation of the dissolving solution. PMID:11771694

  12. Recent advances in production of succinic acid from lignocellulosic biomass.

    PubMed

    Akhtar, Junaid; Idris, Ani; Abd Aziz, Ramlan

    2014-02-01

    Production of succinic acid via separate enzymatic hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) are alternatives and are environmentally friendly processes. These processes have attained considerable positions in the industry with their own share of challenges and problems. The high-value succinic acid is extensively used in chemical, food, pharmaceutical, leather and textile industries and can be efficiently produced via several methods. Previously, succinic acid production via chemical synthesis from petrochemical or refined sugar has been the focus of interest of most reviewers. However, these expensive substrates have been recently replaced by alternative sustainable raw materials such as lignocellulosic biomass, which is cheap and abundantly available. Thus, this review focuses on succinic acid production utilizing lignocellulosic material as a potential substrate for SSF and SHF. SSF is an economical single-step process which can be a substitute for SHF - a two-step process where biomass is hydrolyzed in the first step and fermented in the second step. SSF of lignocellulosic biomass under optimum temperature and pH conditions results in the controlled release of sugar and simultaneous conversion into succinic acid by specific microorganisms, reducing reaction time and costs and increasing productivity. In addition, main process parameters which influence SHF and SSF processes such as batch and fed-batch fermentation conditions using different microbial strains are discussed in detail. PMID:24292125

  13. Production rates of cosmogenic nuclei on the lunar surface

    NASA Astrophysics Data System (ADS)

    Dong, Tie-Kuang; Yun, Su-Jun; Ma, Tao; Chang, Jin; Dong, Wu-Dong; Zhang, Xiao-Ping; Li, Guo-Long; Ren, Zhong-Zhou

    2014-07-01

    A physical model for Geant4-based simulation of the galactic cosmic ray (GCR) particles' interaction with the lunar surface matter has been developed to investigate the production rates of cosmogenic nuclei. In this model the GCRs, mainly very high energy protons and α particles, bombard the surface of the Moon and produce many secondary particles, such as protons and neutrons. The energies of protons and neutrons at different depths are recorded and saved as ROOT files, and the analytical expressions for the differential proton and neutron fluxes are obtained through the best-fit procedure using ROOT software. To test the validity of this model, we calculate the production rates of the long-lived nuclei 10Be and 26Al in the Apollo 15 long drill core by combining the above differential fluxes and the newly evaluated spallation reaction cross sections. Our numerical results show that the theoretical production rates agree quite well with the measured data, which means that this model works well. Therefore, it can be expected that this model can be used to investigate the cosmogenic nuclei in future lunar samples returned by the Chinese lunar exploration program and can be extended to study other objects, such as meteorites and the Earth's atmosphere.

  14. Microwave-assisted biodiesel production by esterification of palm fatty acid distillate.

    PubMed

    Lokman, Ibrahim M; Rashid, Umer; Zainal, Zulkarnain; Yunus, Robiah; Taufiq-Yap, Yun Hin

    2014-01-01

    In the current research work, effect of microwave irradiation energy on the esterification of palm fatty acid distillate (PFAD) to produce PFAD methyl ester / biodiesel was intensively appraised. The PFAD is a by-product from refinery of crude palm oil consisting >85% of free fatty acid (FFA). The esterification reaction process with acid catalyst is needed to convert the FFA into fatty acid methyl ester or known as biodiesel. In this work, fabricated microwave-pulse width modulation (MPWM) reactor with controlled temperature was designed to be capable to increase the PFAD biodiesel production rate. The classical optimization technique was used in order to study the relationship and the optimum condition of variables involved. Consequently, by using MPWM reactor, mixture of methanol-to-PFAD molar ratio of 9:1, 1 wt.% of sulfuric acid catalyst, at 55°C reaction temperature within 15 min reaction time gave 99.5% of FFA conversion. The quality assessment and properties of the product were analyzed according to the American Society for Testing and Materials (ASTM), European (EN) standard methods and all results were in agreement with the standard requirements. It revealed that the use of fabricated MPWM with controlled temperature was significantly affecting the rate of esterification reaction and also increased the production yield of PFAD methyl ester. PMID:25099911

  15. Propionic acid production by immobilized cells of a propionate-tolerant strain of Propionibacterium acidipropionici.

    PubMed

    Paik, H D; Glatz, B A

    1994-10-01

    Cells of the propionate-tolerant strain Propionibacterium acidipropionici P200910, immobilized in calcium alginate beads, were tested for propionic and acetic acid production both in a semidefined laboratory medium and in corn steep liquor in batch, fed-batch, and continuous fermentation. Cell density was about 9.8 x 10(9) cells/g (wet weight) of beads, and beads were added to the medium at 0.1 g (wet weight) beads/ml. Beads could be reused for several consecutive batch fermentations; propionic acid production in the tenth cycle was about 50%-70% of that in the first cycle. In batch culture complete substrate consumption (glucose in semidefined medium, lactate in corn steep liquor) and maximum acid production were seen within 36 h, and acid yields from the substrate were higher than in free-cell fermentations. Fed-batch fermentations were incubated up to 250 h. Maximum propionic acid concentrations obtained were 45.6 g/l in corn steep liquor and 57 g/l in semidefined medium; this is the highest concentration achieved to date in our laboratory. Maximum acetic acid concentrations were 17 g/l and 12 g/l, respectively. In continuous fermentation of semide-fined medium, dilution rates up to 0.31 h-1 could be used, which gave higher volumetric productivities (0.96 g l-1 h-1 for propionic acid and 0.26 g l-1 h-1 for acetic acid) than we have obtained with free cells. Corn steep liquor shows promise as an inexpensive medium for production of both acids by immobilized cells of propionibacteria. PMID:7765817

  16. 5 CFR 532.253 - Special rates or rate ranges for leader, supervisory, and production facilitating positions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 1 2010-01-01 2010-01-01 false Special rates or rate ranges for leader, supervisory, and production facilitating positions. 532.253 Section 532.253 Administrative Personnel OFFICE OF....253 Special rates or rate ranges for leader, supervisory, and production facilitating positions....

  17. 5 CFR 532.253 - Special rates or rate ranges for leader, supervisory, and production facilitating positions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 1 2013-01-01 2013-01-01 false Special rates or rate ranges for leader, supervisory, and production facilitating positions. 532.253 Section 532.253 Administrative Personnel OFFICE OF....253 Special rates or rate ranges for leader, supervisory, and production facilitating positions....

  18. 5 CFR 532.253 - Special rates or rate ranges for leader, supervisory, and production facilitating positions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 1 2012-01-01 2012-01-01 false Special rates or rate ranges for leader, supervisory, and production facilitating positions. 532.253 Section 532.253 Administrative Personnel OFFICE OF....253 Special rates or rate ranges for leader, supervisory, and production facilitating positions....

  19. 5 CFR 532.253 - Special rates or rate ranges for leader, supervisory, and production facilitating positions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 1 2011-01-01 2011-01-01 false Special rates or rate ranges for leader, supervisory, and production facilitating positions. 532.253 Section 532.253 Administrative Personnel OFFICE OF....253 Special rates or rate ranges for leader, supervisory, and production facilitating positions....

  20. 2012: no trans fatty acids in Spanish bakery products.

    PubMed

    Ansorena, Diana; Echarte, Andrea; Ollé, Rebeca; Astiasarán, Iciar

    2013-05-01

    Trans fatty acids (TFA) are strongly correlated with an increased risk of cardiovascular and other chronic diseases. Current dietary recommendations exclude bakery products from frequent consumption basically due to their traditionally high content of TFA. The aim of this work was to analyse the lipid profile of different bakery products currently commercialised in Spain and with a conventionally high fat and TFA content. Premium and store brands for each product were included in the study. No significant amounts of TFA were found in any of the analysed products, regardless the brand. TFA content ranged between 0.17 g and 0.22 g/100 g product (mean=0.19 g/100 g product). Expressed on percentage of fatty acids, the maximum value was 0.87 g/100 g fatty acids and the mean value was 0.68%. These data are significantly lower than those observed in previously published papers for these types of products, and highlighted the importance of updating food composition databases in order to accurately estimate the real and current intake of TFA. PMID:23265507

  1. Bio-based production of organic acids with Corynebacterium glutamicum.

    PubMed

    Wieschalka, Stefan; Blombach, Bastian; Bott, Michael; Eikmanns, Bernhard J

    2013-03-01

    The shortage of oil resources, the steadily rising oil prices and the impact of its use on the environment evokes an increasing political, industrial and technical interest for development of safe and efficient processes for the production of chemicals from renewable biomass. Thus, microbial fermentation of renewable feedstocks found its way in white biotechnology, complementing more and more traditional crude oil-based chemical processes. Rational strain design of appropriate microorganisms has become possible due to steadily increasing knowledge on metabolism and pathway regulation of industrially relevant organisms and, aside from process engineering and optimization, has an outstanding impact on improving the performance of such hosts. Corynebacterium glutamicum is well known as workhorse for the industrial production of numerous amino acids. However, recent studies also explored the usefulness of this organism for the production of several organic acids and great efforts have been made for improvement of the performance. This review summarizes the current knowledge and recent achievements on metabolic engineering approaches to tailor C. glutamicum for the bio-based production of organic acids. We focus here on the fermentative production of pyruvate, L- and D-lactate, 2-ketoisovalerate, 2-ketoglutarate, and succinate. These organic acids represent a class of compounds with manifold application ranges, e.g. in pharmaceutical and cosmetics industry, as food additives, and economically very interesting, as precursors for a variety of bulk chemicals and commercially important polymers. PMID:23199277

  2. Evolution for exogenous octanoic acid tolerance improves carboxylic acid production and membrane integrity.

    PubMed

    Royce, Liam A; Yoon, Jong Moon; Chen, Yingxi; Rickenbach, Emily; Shanks, Jacqueline V; Jarboe, Laura R

    2015-05-01

    Carboxylic acids are an attractive biorenewable chemical, but as with many biorenewables, their toxicity to microbial biocatalysts limits their fermentative production. While it is generally accepted that membrane damage is the main mechanism of fatty acid toxicity, previous metabolic engineering efforts that increased membrane integrity did not enable increased carboxylic acid production. Here we used an evolutionary approach to improve tolerance to exogenous octanoic acid, with the goal of learning design strategies from this evolved strain. This evolution of an Escherichia coli MG1655 derivative at neutral pH in minimal media produced a strain with increased tolerance not only to octanoic acid, but also to hexanoic acid, decanoic acid, n-butanol and isobutanol. This evolved strain also produced carboxylic acids at a 5-fold higher titer than its parent strain when expressing the Anaerococcus tetradius thioesterase. While it has been previously suggested that intracellular acidification may contribute to carboxylic acid toxicity, we saw no evidence that the evolved strain has increased resistance to this acidification. Characterization of the evolved strain membrane showed that it had significantly altered membrane polarization (fluidity), integrity (leakage) and composition relative to its parent. The changes in membrane composition included a significant increase in average lipid length in a variety of growth conditions, including 30°C, 42°C, carboxylic acid challenge and ethanol challenge. The evolved strain has a more dynamic membrane composition, showing both a larger number of significant changes and larger fold changes in the relative abundance of membrane lipids. These results highlight the importance of the cell membrane in increasing microbial tolerance and production of biorenewable fuels and chemicals. PMID:25839166

  3. Estimates of Biogenic Methane Production Rates in Deep Marine Sediments

    NASA Astrophysics Data System (ADS)

    Colwell, F. S.; Boyd, S.; Delwiche, M. E.; Reed, D. W.

    2004-12-01

    Much of the methane in natural gas hydrates in marine sediments is made by methanogens. Current models used to predict hydrate distribution and concentration in these sediments require estimates of microbial methane production rates. However, accurate estimates are difficult to achieve because of the bias introduced by sampling and because methanogen activities in these sediments are low and not easily detected. To derive useful methane production rates for marine sediments we have measured the methanogen biomass in samples taken from different depths in Hydrate Ridge (HR) sediments off the coast of Oregon and, separately, the minimal rates of activity for a methanogen in a laboratory reactor. For methanogen biomass, we used a polymerase chain reaction assay in real time to target the methanogen-specific mcr gene. Using this method we found that a majority of the samples collected from boreholes at HR show no evidence of methanogens (detection limit: less than 100 methanogens per g of sediment). Most of the samples with detectable numbers of methanogens were from shallow sediments (less than 10 meters below seafloor [mbsf]) although a few samples with apparently high numbers of methanogens (greater than 10,000 methanogens per g) were from as deep as 230 mbsf and were associated with notable geological features (e.g., the bottom-simulating reflector and an ash-bearing zone with high fluid movement). Laboratory studies with Methanoculleus submarinus (isolated from a hydrate zone at the Nankai Trough) maintained in a biomass recycle reactor showed that when this methanogen is merely surviving, as is likely the case in deep marine sediments, it produces approximately 0.06 fmol methane per cell per day. This is far lower than rates reported for methanogens in other environments. By combining this estimate of specific methanogenic rates and an extrapolation from the numbers of methanogens at selected depths in the sediment column at HR sites we have derived a maximum

  4. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production

    PubMed Central

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2– 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g-1 dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6–9.5 mg· g-1 dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model. PMID:24031799

  5. Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion.

    PubMed

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y; Nghiem, L D; Hai, F I; Deng, L J; Wang, J; Wu, Y

    2016-11-01

    The anaerobic digestion process has been primarily utilized for methane containing biogas production over the past few years. However, the digestion process could also be optimized for producing volatile fatty acids (VFAs) and biohydrogen. This is the first review article that combines the optimization approaches for all three possible products from the anaerobic digestion. In this review study, the types and configurations of the bioreactor are discussed for each type of product. This is followed by a review on optimization of common process parameters (e.g. temperature, pH, retention time and organic loading rate) separately for the production of VFA, biohydrogen and methane. This review also includes additional parameters, treatment methods or special additives that wield a significant and positive effect on production rate and these products' yield. PMID:27570139

  6. Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

  7. A model of northern pintail productivity and population growth rate

    USGS Publications Warehouse

    Flint, P.L.; Grand, J.B.; Rockwell, R.F.

    1998-01-01

    Our objective was to synthesize individual components of reproductive ecology into a single estimate of productivity and to assess the relative effects of survival and productivity on population dynamics. We used information on nesting ecology, renesting potential, and duckling survival of northern pintails (Anas acuta) collected on the Yukon-Kuskokvim Delta (Y-K Delta), Alaska, 1991-95, to model the number of ducklings produced under a range of nest success and duckling survival probabilities. Using average values of 25% nest success, 11% duckling survival, and 56% renesting probability from our study population, we calculated that all young in our population were produced by 13% of the breeding females, and that early-nesting females produced more young than later-nesting females. Further, we calculated, on average, that each female produced only 0.16 young females/nesting season. We combined these results with estimates of first-year and adult survival to examine the growth rate (??) of the population and the relative contributions of these demographic parameters to that growth rate. Contrary to aerial survey data, the population projection model suggests our study population is declining rapidly (?? = 0.6969). The relative effects on population growth rate were 0.1175 for reproductive success, 0.1175 for first-year survival, and 0.8825 for adult survival. Adult survival had the greatest influence on ?? for our population, and this conclusion was robust over a range of survival and productivity estimates. Given published estimates of annual survival for adult females (61%), our model suggested nest success and duckling survival need to increase to approximately 40% to achieve population stability. We discuss reasons for the apparent discrepancy in population trends between our model and aerial surveys in terms of bias in productivity and survival estimates.

  8. Degradation of caffeic acid in subcritical water and online HPLC-DPPH assay of degradation products.

    PubMed

    Khuwijitjaru, Pramote; Suaylam, Boonyanuch; Adachi, Shuji

    2014-02-26

    Caffeic acid was subjected to degradation under subcritical water conditions within 160-240 °C and at a constant pressure of 5 MPa in a continuous tubular reactor. Caffeic acid degraded quickly at these temperatures; the main products identified by liquid chromatography-diode array detection/mass spectrometry were hydroxytyrosol, protocatechuic aldehyde, and 4-vinylcatechol. The reaction rates for the degradation of caffeic acid and the formation of products were evaluated. Online high-performance liquid chromatography/2,2-diphenyl-1-picryhydrazyl assay was used to determine the antioxidant activity of each product in the solution. It was found that the overall antioxidant activity of the treated solution did not change during the degradation process. This study showed a potential of formation of antioxidants from natural phenolic compounds under these subcritical water conditions, and this may lead to a discovering of novel antioxidants compounds during the extraction by this technique. PMID:24483598

  9. Anaerobic microbial dissolution of lead and production of organic acids

    DOEpatents

    Francis, A.J.; Dodge, C.; Chendrayan, K.; Quinby, H.L.

    1987-04-16

    The present invention related to an anaerobic bacterial culture of Clostridium sp. ATCC No. 53464 which solubilizes lead oxide under anaerobic conditions in coal and industrial wastes and therefore presents a method of removing lead from such wastes before they are dumped into the environment. The rat of lead dissolution during logarithmic growth of the bacteria in 40 ml medium containing 3.32 ..mu..moles of lead as lead oxide was 0.042 ..mu..moles m1/sup /-/1/ hr/sup /-/1/. Dissolution of lead oxide by the bacterial isolate is due to the production of metabolites and acidity in the culture medium. The major metabolites are acetic, butyric and lactic acid. The major metabolites are acetic, butyric and lactic acid. Clostridium sp. ATCC No. 53464 can be used in the recovery of the strategic metals from ores and wastes and also for the production of lactic acid for commercial purposes. The process yields large quantities of lactic acid as well as lead complexed in a stable form with said acids. 4 figs., 3 tabs.

  10. Metabolic engineering of Saccharomyces cerevisiae for itaconic acid production.

    PubMed

    Blazeck, John; Miller, Jarrett; Pan, Anny; Gengler, Jon; Holden, Clinton; Jamoussi, Mariam; Alper, Hal S

    2014-10-01

    Renewable alternatives for petroleum-derived chemicals are achievable through biosynthetic production. Here, we utilize Saccharomyces cerevisiae to enable the synthesis of itaconic acid, a molecule with diverse applications as a petrochemical replacement. We first optimize pathway expression within S. cerevisiae through the use of a hybrid promoter. Next, we utilize sequential, in silico computational genome-scanning to identify beneficial genetic perturbations that are metabolically distant from the itaconic acid synthesis pathway. In this manner, we successfully identify three non-obvious genetic targets (∆ade3 ∆bna2 ∆tes1) that successively improve itaconic acid titer. We establish that focused manipulations of upstream pathway enzymes (localized refactoring) and enzyme re-localization to both mitochondria and cytosol fail to improve itaconic acid titers. Finally, we establish a higher cell density fermentation that ultimately achieves itaconic acid titer of 168 mg/L, a sevenfold improvement over initial conditions. This work represents an attempt to increase itaconic acid production in yeast and demonstrates the successful utilization of computationally guided genetic manipulation to increase metabolic capacity. PMID:24997118

  11. Production of ω-hydroxy octanoic acid with Escherichia coli.

    PubMed

    Kirtz, Marko; Klebensberger, Janosch; Otte, Konrad B; Richter, Sven M; Hauer, Bernhard

    2016-07-20

    The present proof-of-concept study reports the construction of a whole-cell biocatalyst for the de novo production of ω-hydroxy octanoic acid. This was achieved by hijacking the natural fatty acid cycle and subsequent hydroxylation using a specific monooxygenase without the need for the additional feed of alkene-like precursors. For this, we used the model organism Escherichia coli and increased primarily the release of the octanoic acid precursors by overexpressing the plant thioesterase FatB2 from Cuphea hookeriana in a β-oxidation deficient strain, which lead to the production of 2.32mM (8.38mggcww(-1)) octanoic acid in 24h. In order to produce the corresponding ω-hydroxy derivative, we additionally expressed the engineered self-sufficient monooxygenase fusion protein CYP153AMaq(G307A)-CPRBM3 within the octanoic acid producing strain. With this, we finally produced 234μM (0.95mggcww(-1)) ω-hydroxy octanoic acid in a 20h fed-batch set-up. PMID:27184430

  12. Amino Acid Degradations Produced by Lipid Oxidation Products.

    PubMed

    Hidalgo, Francisco J; Zamora, Rosario

    2016-06-10

    Differently to amino acid degradations produced by carbohydrate-derived reactive carbonyls, amino acid degradations produced by lipid oxidation products are lesser known in spite of being lipid oxidation a major source of reactive carbonyls in food. This article analyzes the conversion of amino acids into Strecker aldehydes, α-keto acids, and amines produced by lipid-derived free radicals and carbonyl compounds, as well as the role of lipid oxidation products on the reactions suffered by these compounds: the formation of Strecker aldehydes and other aldehydes from α-keto acids; the formation of Strecker aldehydes and olefins from amines; the formation of shorter aldehydes from Strecker aldehydes; and the addition reactions suffered by the olefins produced from the amines. The relationships among all these reactions and the effect of reaction conditions on them are discussed. This knowledge should contribute to better control food processing in order to favor the formation of desirable beneficial compounds and to inhibit the production of compounds with deleterious properties. PMID:25748518

  13. Blood levels and production rate of 17-hydroxypregnenolone in man

    PubMed Central

    Strott, C. A.; Bermudez, J. A.; Lipsett, M. B.

    1970-01-01

    A reliable radio-ligand assay has been developed for the measurement of 17-hydroxypregnenolone in human peripheral vein plasma. The mean plasma concentration of 17-hydroxypregnenolone was, in men, 1.9 mμg/ml; and in women, 3.5 mμg/ml. These means were not significantly different from each other, and the levels were the same in the follicular and luteal phases of the menstrual cycle. In women, the adrenal cortex was the source of the 17-hydroxypregnenolone; in men, 40% was produced by the testis. Since the metabolic clearance rate was about 2000 liters/24 hr production rate estimates were 4-7 mg/24 hr. The conversion of blood 17-hydroxypregnenolone to blood 17-hydroxyprogesterone and dehydroepiandrosterone was measured. This varied from 5 to 20%. Thus, in women during the follicular phase, 17-hydroxyprogesterone derived from blood 17-hydroxypregnenolone could be the major fraction of the 17-hydroxyprogesterone production rate. Blood 17-hydroxypregnenolone is a minor precursor of blood dehydroepiandrosterone. PMID:4248912

  14. Production and Degradation of Oxalic Acid by Brown Rot Fungi

    PubMed Central

    Espejo, Eduardo; Agosin, Eduardo

    1991-01-01

    Our results show that all of the brown rot fungi tested produce oxalic acid in liquid as well as in semisolid cultures. Gloeophyllum trabeum, which accumulates the lowest amount of oxalic acid during decay of pine holocellulose, showed the highest polysaccharide-depolymerizing activity. Semisolid cultures inoculated with this fungus rapidly converted 14C-labeled oxalic acid to CO2 during cellulose depolymerization. The other brown rot fungi also oxidized 14C-labeled oxalic acid, although less rapidly. In contrast, semisolid cultures inoculated with the white rot fungus Coriolus versicolor did not significantly catabolize the acid and did not depolymerize the holocellulose during decay. Semisolid cultures of G. trabeum amended with desferrioxamine, a specific iron-chelating agent, were unable to lower the degree of polymerization of cellulose or to oxidize 14C-labeled oxalic acid to the extent or at the rate that control cultures did. These results suggest that both iron and oxalic acid are involved in cellulose depolymerization by brown rot fungi. PMID:16348522

  15. The influence of phosphorus oxides and acids on the rate of H + OH recombination

    SciTech Connect

    Twarowski, A. )

    1993-07-01

    The addition of small amounts of phosphine combustion products (phosphorus oxides and acids) to water vapor resulted in a large increase in the relaxation rate of OH to equilibrium concentrations following H[sub 2]O photolysis. The thermochemical properties of 17 simple phosphorus species were assembled and the equilibrium densities of the phosphorus species were calculated under typical test conditions. The thermochemical properties of many of the phosphorus species have not been determined but for the purposes of this analysis they were estimated from the results of ab initio quantum chemical calculations available in the literature. Of the phosphorus species examined, eight were selected for construction of a reaction set. Thirteen species (7 HxOy species and 6 HxOyPz species) were ultimately used to assemble a set of 33 reactions which comprise all of the bimolecular reactions (including recombination reactions) likely to participate in the overall reaction chemistry. Rate constant values were estimated using standard methods for the metathesis reactions and using simplified RRKM calculations to estimate the rates of recombination reactions. The increase rate of OH recovery was well described by this reaction set at the experimental conditions of 1,970 K and 532 Torr. The two reaction mechanisms OH + PH[sub 2] [yields] HOPO[sub 2], H + HOPO[sub 2] [yields] H[sub 2]O + PO[sub 2], and H + PO[sub 2] [yields] HOPO, OH + H[sub 2] [yields] H[sub 2]O + H, H + HOPO [yields] H[sub 2] + PO[sub 2] appear to be the predominant pathways for recombination of H and OH radicals to form H[sub 2]O and for reestablishment of chemical equilibrium when phosphine combustion products are present in the reaction mixture.

  16. Production of gaba (γ - Aminobutyric acid) by microorganisms: a review.

    PubMed

    Dhakal, Radhika; Bajpai, Vivek K; Baek, Kwang-Hyun

    2012-10-01

    GABA (γ-aminobutyric acid) is a four carbon non-protein amino acid that is widely distributed in plants, animals and microorganisms. As a metabolic product of plants and microorganisms produced by the decarboxylation of glutamic acid, GABA functions as an inhibitory neurotransmitter in the brain that directly affects the personality and the stress management. A wide range of traditional foods produced by microbial fermentation contain GABA, in which GABA is safe and eco-friendly, and also has the possibility of providing new health-benefited products enriched with GABA. Synthesis of GABA is catalyzed by glutamate decarboxylase, therefore, the optimal fermentation condition is mainly based on the biochemical properties of the enzyme. Major GABA producing microorganisms are lactic acid bacteria (LAB), which make food spoilage pathogens unable to grow and act as probiotics in the gastrointestinal tract. The major factors affecting the production of GABA by microbial fermentation are temperature, pH, fermentation time and different media additives, therefore, these factors are summarized to provide the most up-dated information for effective GABA synthesis. There has been a huge accumulation of knowledge on GABA application for human health accompanying with a demand on natural GABA supply. Only the GABA production by microorganisms can fulfill the demand with GABA-enriched health beneficial foods. PMID:24031948

  17. Conjugated Linoleic Acid Production by Bifidobacteria: Screening, Kinetic, and Composition

    PubMed Central

    Amaretti, Alberto; Leonardi, Alan; Quartieri, Andrea; Gozzoli, Caterina; Rossi, Maddalena

    2016-01-01

    Conjugated linoleic acids (CLA) are positional and geometric isomers of linoleic acid involved in a number of health aspects. In humans, CLA production is performed by gut microbiota, including some species of potential probiotic bifidobacteria. 128 strains of 31 Bifidobacterium species were screened with a spectrophotometric assay to identify novel CLA producers. Most species were nonproducers, while producers belonged to B. breve and B. pseudocatenulatum. GC-MS revealed that CLA producer strains yielded 9cis,11trans-CLA and 9trans,11trans-CLA, without any production of other isomers. Hydroxylated forms of LA were absent in producer strains, suggesting that the myosin-cross-reactive antigen (MCRA) protein that exerts hydratase activity is not involved in LA isomerization. Moreover, both CLA producer and nonproducer species bear a MCRA homologue. The strain B. breve WC 0421 was the best CLA producer, converting LA into 68.8% 9cis,11trans-CLA and 25.1% 9trans,11trans-CLA. Production occurred mostly during the lag and the exponential phase. For the first time, production and incorporation of CLA in biomass were assessed. B. breve WC 0421 stored CLA in the form of free fatty acids, without changing the composition of the esterified fatty acids, which mainly occurred in the plasmatic membrane. PMID:27429985

  18. Thermodynamic analysis of acetic acid steam reforming for hydrogen production

    NASA Astrophysics Data System (ADS)

    Goicoechea, Saioa; Ehrich, Heike; Arias, Pedro L.; Kockmann, Norbert

    2015-04-01

    A thermodynamic analysis of hydrogen generation by acetic acid steam reforming has been carried out with respect to applications in solid oxide fuel cells. The effect of operating parameters on equilibrium composition has been examined focusing especially on hydrogen and carbon monoxide production, which are the fuels in this type of fuel cell. The temperature, steam to acetic acid ratio, and to a lesser extent pressure affect significantly the equilibrium product distribution due to their influence on steam reforming, thermal decomposition and water-gas shift reaction. The study shows that steam reforming of acetic acid with a steam to acetic acid ratio of 2 to 1 is thermodynamically feasible with hydrogen, carbon monoxide and water as the main products at the equilibrium at temperatures higher than 700 °C, and achieving CO/CO2 ratios higher than 1. Thus, it can be concluded that within the operation temperature range of solid oxide fuel cells - between 700 °C and 1000 °C - the production of a gas rich in hydrogen and carbon monoxide is promoted.

  19. Detoxification of acidic biorefinery waste liquor for production of high value amino acid.

    PubMed

    Christopher, Meera; Anusree, Murali; Mathew, Anil K; Nampoothiri, K Madhavan; Sukumaran, Rajeev Kumar; Pandey, Ashok

    2016-08-01

    The current study evaluates the detoxification of acid pretreatment liquor (APL) using adsorbent (ADS 400 & ADS 800) or ion-exchange (A-27MP & A-72MP) resins and its potential for amino acid production. The APL is generated as a by-product from the pretreatment of lignocellulosic biomass and is rich monomeric sugars as well as sugar degradation products (fermentation inhibitors) such as furfural and hydroxymethyl furfural (HMF). Of the four resins compared, ADS 800 removed approximately 85% and 60% of furfural and HMF, respectively. ADS 800 could be reused for up to six cycles after regeneration without losing its adsorption properties. The study was further extended by assessing the fermentability of detoxified APL for l-lysine production using wild and mutant strains of Corynebacterium glutamicum. The detoxified APL was superior to APL for l-lysine production. PMID:26996259

  20. Modifications of proteins by polyunsaturated fatty acid peroxidation products

    NASA Astrophysics Data System (ADS)

    Refsgaard, Hanne H. F.; Tsai, Lin; Stadtman, Earl R.

    2000-01-01

    The ability of unsaturated fatty acid methyl esters to modify amino acid residues in bovine serum albumin (BSA), glutamine synthetase, and insulin in the presence of a metal-catalyzed oxidation system [ascorbate/Fe(III)/O2] depends on the degree of unsaturation of the fatty acid. The fatty acid-dependent generation of carbonyl groups and loss of lysine residues increased in the order methyl linoleate < methyl linolenate < methyl arachidonate. The amounts of alkyl hydroperoxides, malondialdehyde, and a number of other aldehydes that accumulated when polyunsaturated fatty acids were oxidized in the presence of BSA were significantly lower than that observed in the absence of BSA. Direct treatment of proteins with various lipid hydroperoxides led to a slight increase in the formation of protein carbonyl derivatives, whereas treatment with the hydroperoxides together with Fe(II) led to a substantial increase in the formation of protein carbonyls. These results are consistent with the proposition that metal-catalyzed oxidation of polyunsaturated fatty acids can contribute to the generation of protein carbonyls by direct interaction of lipid oxidation products (α,β-unsaturated aldehydes) with lysine residues (Michael addition reactions) and also by interactions with alkoxyl radicals obtained by Fe(II) cleavage of lipid hydroperoxides that are formed. In addition, saturated aldehydes derived from the polyunsaturated fatty acids likely react with lysine residues to form Schiff base adducts.

  1. Modifications of proteins by polyunsaturated fatty acid peroxidation products

    PubMed Central

    Refsgaard, Hanne H. F.; Tsai, Lin; Stadtman, Earl R.

    2000-01-01

    The ability of unsaturated fatty acid methyl esters to modify amino acid residues in bovine serum albumin (BSA), glutamine synthetase, and insulin in the presence of a metal-catalyzed oxidation system [ascorbate/Fe(III)/O2] depends on the degree of unsaturation of the fatty acid. The fatty acid-dependent generation of carbonyl groups and loss of lysine residues increased in the order methyl linoleate < methyl linolenate < methyl arachidonate. The amounts of alkyl hydroperoxides, malondialdehyde, and a number of other aldehydes that accumulated when polyunsaturated fatty acids were oxidized in the presence of BSA were significantly lower than that observed in the absence of BSA. Direct treatment of proteins with various lipid hydroperoxides led to a slight increase in the formation of protein carbonyl derivatives, whereas treatment with the hydroperoxides together with Fe(II) led to a substantial increase in the formation of protein carbonyls. These results are consistent with the proposition that metal-catalyzed oxidation of polyunsaturated fatty acids can contribute to the generation of protein carbonyls by direct interaction of lipid oxidation products (α,β-unsaturated aldehydes) with lysine residues (Michael addition reactions) and also by interactions with alkoxyl radicals obtained by Fe(II) cleavage of lipid hydroperoxides that are formed. In addition, saturated aldehydes derived from the polyunsaturated fatty acids likely react with lysine residues to form Schiff base adducts. PMID:10639127

  2. Lactic Acid and Biosurfactants Production from Residual Cellulose Films.

    PubMed

    Portilla Rivera, Oscar Manuel; Arzate Martínez, Guillermo; Jarquín Enríquez, Lorenzo; Vázquez Landaverde, Pedro Alberto; Domínguez González, José Manuel

    2015-11-01

    The increasing amounts of residual cellulose films generated as wastes all over the world represent a big scale problem for the meat industry regarding to environmental and economic issues. The use of residual cellulose films as a feedstock of glucose-containing solutions by acid hydrolysis and further fermentation into lactic acid and biosurfactants was evaluated as a method to diminish and revalorize these wastes. Under a treatment consisting in sulfuric acid 6% (v/v); reaction time 2 h; solid liquid ratio 9 g of film/100 mL of acid solution, and temperature 130 °C, 35 g/L of glucose and 49% of solubilized film was obtained. From five lactic acid strains, Lactobacillus plantarum was the most suitable for metabolizing the glucose generated. The process was scaled up under optimized conditions in a 2-L bioreactor, producing 3.4 g/L of biomass, 18 g/L of lactic acid, and 15 units of surface tension reduction of a buffer phosphate solution. Around 50% of the cellulose was degraded by the treatment applied, and the liqueurs generated were useful for an efficient production of lactic acid and biosurfactants using L. plantarum. Lactobacillus bacteria can efficiently utilize glucose from cellulose films hydrolysis without the need of clarification of the liqueurs. PMID:26293409

  3. Assessing hydrodynamic effects on jarosite dissolution rates, reaction products, and preservation on Mars

    NASA Astrophysics Data System (ADS)

    Dixon, Emily M.; Elwood Madden, Andrew S.; Hausrath, Elisabeth M.; Elwood Madden, Megan E.

    2015-04-01

    Jarosite flow-through dissolution experiments were conducted in ultrapure water (UPW), pH 2 sulfuric acid, and saturated NaCl and CaCl2 brines at 295-298 K to investigate how hydrologic variables may affect jarosite preservation and reaction products on Mars. K+-based dissolution rates in flowing UPW did not vary significantly with flow rate, indicating that mineral surface reactions control dissolution rates over the range of flow rates investigated. In all of the solutions tested, hydrologic variables do not significantly affect extent of jarosite alteration; therefore, jarosite is equally likely to be preserved in flowing or stagnant waters on Mars. However, increasing flow rate did affect the mineralogy and accumulation of secondary reaction products. Iron release rates in dilute solutions increased as the flow rate increased, likely due to nanoscale iron (hydr)oxide transport in flowing water. Anhydrite formed in CaCl2 brine flow-through experiments despite low temperatures, while metastable gypsum and bassanite were observed in batch experiments. Therefore, observations of the hydration state of calcium sulfate minerals on Mars may provide clues to unravel past salinity and hydrologic conditions as well as temperatures and vapor pressures.

  4. Thermochemical pretreatment of lignocellulose to enhance methane fermentation. I. Monosaccharide and furfurals hydrothermal decomposition and product formation rates

    SciTech Connect

    Baugh, K.D.; McCarty, P.L.

    1988-01-01

    Over a pH range 1-4 and temperatures from 170 to 230/sup 0/C, the decomposition rates of xylose, galactose, mannose, glucose, 2-furfural, and 5-hydroxymethyl-2-furfural (5-HMF) were pseudo first order. The effect of temperature and pH on the pseudo first-order decomposition rate constants was modeled using the Arrhenius equation and acid-base catalysis, respectively. Decomposition rates of the monosaccharides were minimum at a pH 2-2.5. Above pH 2.5, the monosaccharide decomposition was base catalyzed, with acid catalysis occurring at a pH of less than 2 for glucose. The furfurals were subject to acid catalysis at below ca. pH 3.5. The hydrothermal conversion of glucose to its decomposition products during thermochemical pretreatment can be modeled as a combination of series and parallel reactions. The formation rates of identified soluble products from glucose decomposition, 5-HMF and levulinic acid, were also functions of temperature and pH. The rate of 5-HMF formation relative to glucose decomposition decreased as the pH increased from 2.0 to 4.0, with levulinic acid formation only detected when the pH was 2.5 or less. For glucose decomposition, humic solids accounted for ca. 20% of the decomposition products.

  5. Forest turnover rates follow global and regional patterns of productivity

    USGS Publications Warehouse

    Stephenson, N.L.; van Mantgem, P.J.

    2005-01-01

    Using a global database, we found that forest turnover rates (the average of tree mortality and recruitment rates) parallel broad-scale patterns of net primary productivity. First, forest turnover was higher in tropical than in temperate forests. Second, as recently demonstrated by others, Amazonian forest turnover was higher on fertile than infertile soils. Third, within temperate latitudes, turnover was highest in angiosperm forests, intermediate in mixed forests, and lowest in gymnosperm forests. Finally, within a single forest physiognomic type, turnover declined sharply with elevation (hence with temperature). These patterns of turnover in populations of trees are broadly similar to the patterns of turnover in populations of plant organs (leaves and roots) found in other studies. Our findings suggest a link between forest mass balance and the population dynamics of trees, and have implications for understanding and predicting the effects of environmental changes on forest structure and terrestrial carbon dynamics. ??2005 Blackwell Publishing Ltd/CNRS.

  6. Universal scaling of production rates across mammalian lineages

    PubMed Central

    Hamilton, Marcus J.; Davidson, Ana D.; Sibly, Richard M.; Brown, James H.

    2011-01-01

    Over many millions of years of independent evolution, placental, marsupial and monotreme mammals have diverged conspicuously in physiology, life history and reproductive ecology. The differences in life histories are particularly striking. Compared with placentals, marsupials exhibit shorter pregnancy, smaller size of offspring at birth and longer period of lactation in the pouch. Monotremes also exhibit short pregnancy, but incubate embryos in eggs, followed by a long period of post-hatching lactation. Using a large sample of mammalian species, we show that, remarkably, despite their very different life histories, the scaling of production rates is statistically indistinguishable across mammalian lineages. Apparently all mammals are subject to the same fundamental metabolic constraints on productivity, because they share similar body designs, vascular systems and costs of producing new tissue. PMID:20798111

  7. Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

    NASA Technical Reports Server (NTRS)

    Somogyi, Dezso; Feiler, Charles E.

    1960-01-01

    The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

  8. The Production Rate and Employment of Ph.D. Astronomers

    NASA Astrophysics Data System (ADS)

    Metcalfe, Travis S.

    2008-02-01

    In an effort to encourage self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astronomy and astrophysics. The average new astronomer might expect to hold up to 3 jobs before finding a steady position.

  9. The Production Rate and Employment of Ph.D. Astronomers

    NASA Astrophysics Data System (ADS)

    Metcalfe, Travis S.

    2007-05-01

    As in many sciences, the production rate of new Ph.D. astronomers is decoupled from the global demand for trained scientists. As noted by Thronson (1991, PASP, 103, 90), overproduction appears to be built into the system, making the mathematical formulation of surplus astronomer production similar to that for industrial pollution models -- an unintended side effect of the process. Following Harris (1994, ASP Conf., 57, 12), I document the production of Ph.D. astronomers from 1990 to 2005 using the online Dissertation Abstracts database. To monitor the changing patterns of employment, I examine the number of postdoctoral, tenure-track, and other jobs advertised in the AAS Job Register during this same period. Although the current situation is clearly unsustainable, it was much worse a decade ago with nearly 7 new Ph.D. astronomers in 1995 for every new tenure-track job. While the number of new permanent positions steadily increased throughout the late 1990's, the number of new Ph.D. recipients gradually declined. After the turn of the century, the production of new astronomers leveled off, but new postdoctoral positions grew dramatically. There has also been recent growth in the number of non-tenure-track lecturer, research, and support positions. This is just one example of a larger cultural shift to temporary employment that is happening throughout society -- it is not unique to astronomy.

  10. In vitro gas production kinetics and short-chain fatty acid production from rumen incubation of diets supplemented with hop cones (Humulus lupulus L.).

    PubMed

    Lavrenčič, A; Levart, A; Košir, I J; Čerenak, A

    2015-04-01

    The aim of this study was to assess the effects of hop cones (Humulus lupulus L.) from two varieties Aurora and Dana, differing in their α- and β-acid contents, on rumen microbial activity measured with in vitro gas production kinetics and short-chain fatty acids (SCFA) production. Hop cones were added to the total mixed dairy cow ration (CONT) in concentrations simulating a cow's daily intake of 50, 100 and 200 g of hop cones - the concentrations of hop cones expressed on a substrate basis were 43, 82 and 153 mg/g of substrate. Substrates were anaerobically incubated in glass syringes, and gas production kinetic parameters were determined by fitting data with the Gompertz model. Gas produced after 24 h (Gas24), maximum fermentation rate (MFR) and time of maximum fermentation rate (TMFR) were calculated from the estimated gas production kinetic parameters. After 24 h of incubation, the fermentation liquids of each substrate were taken for the determination of SCFA. Increasing the hop cone concentration decreased the total potential gas production, Gas24, MFR and shortened TMFR. The highest hop cone concentration significantly decreased acetic and butyric acid productions and total SCFA production after 24 h of incubation, but not propionic acid production, resulting in a decreased ratio between acetic acid and propionic acid. PMID:25475691

  11. An overview of conjugated linoleic acid: microbial production and application.

    PubMed

    Gholami, Zahra; Khosravi-Darani, Kianoush

    2014-01-01

    Conjugated linoleic acid (CLA) has attracted considerable attention in health due to its important physiological properties proved in several in vivo experiments. Many bacteria, especially some probiotics, are able to produce CLA from the linoleic acid (LA) present in milk. In this review, CLA production by microorganisms is described. Then factors on the influencing the microbial production and the initial CLA content in milk fat are introduced. After a glimpse on the content of CLA in dairy products and human body, health benefits of CLA including anti-cancer, anti-diabetic, antiathrosclerosis and anti-osteoporosis properties, as well as prevention of body fat increase and function as stimulator of the immunity system are explained. PMID:25138090

  12. Succinic acid production from lignocellulosic hydrolysate by Basfia succiniciproducens.

    PubMed

    Salvachúa, Davinia; Smith, Holly; St John, Peter C; Mohagheghi, Ali; Peterson, Darren J; Black, Brenna A; Dowe, Nancy; Beckham, Gregg T

    2016-08-01

    The production of chemicals alongside fuels will be essential to enhance the feasibility of lignocellulosic biorefineries. Succinic acid (SA), a naturally occurring C4-diacid, is a primary intermediate of the tricarboxylic acid cycle and a promising building block chemical that has received significant industrial attention. Basfia succiniciproducens is a relatively unexplored SA-producing bacterium with advantageous features such as broad substrate utilization, genetic tractability, and facultative anaerobic metabolism. Here B. succiniciproducens is evaluated in high xylose-content hydrolysates from corn stover and different synthetic media in batch fermentation. SA titers in hydrolysate at an initial sugar concentration of 60g/L reached up to 30g/L, with metabolic yields of 0.69g/g, and an overall productivity of 0.43g/L/h. These results demonstrate that B. succiniciproducens may be an attractive platform organism for bio-SA production from biomass hydrolysates. PMID:27179951

  13. Covalent interaction of ascorbic acid with natural products

    PubMed Central

    Kesinger, Nicholas G.; Stevens, Jan F.

    2009-01-01

    While ascorbic acid (Vitamin C) is mostly known as a cofactor for proline hydroxylase and as a biological antioxidant, it also forms covalent bonds with natural products which we here refer to as ‘ascorbylation’. A number of natural products containing an ascorbate moiety has been isolated and characterized from a variety of biological sources, ranging from marine algae to flowering plants. Most of these compounds are formed as a result of nucleophilic substitution or addition by ascorbate, e.g. the ascorbigens from Brassica species are ascorbylated indole derivatives. Some ascorbylated tannins appear to be formed from electrophilic addition to dehydroascorbic acid. There are also examples of annulations of ascorbate with dietary polyphenols, e.g., epigallocatechin gallate (EGCG) and resveratrol derivatives. Herein is a survey of thirty-three ascorbylated natural products and their reported biological activities. PMID:19875138

  14. Road Sediment Production and Delivery: Processes, Rates, and Possible Improvements

    NASA Astrophysics Data System (ADS)

    MacDonald, Lee; Ramos-Scharron, Carlos; Coe, Drew; Stafford, Alexander; Welsh, Matthew; Korte, Abby; Libohova, Zamir; Brown, Ethan; James, Cajun

    2013-04-01

    Unpaved roads are increasingly recognized as one of the largest sources of anthropogenic sediment in forested areas. For nearly 20 years we have been studying road surface erosion and sediment delivery across widely varying environments in California, Colorado, and the Caribbean. The objectives of this paper are to: 1) compare road sediment production and delivery rates across different environments; 2) summarize the primary controls on road surface erosion and sediment delivery; 3) estimate the relative contribution of roads to watershed-scale sediment yields; and 4) suggest management practices to minimize road sediment production and delivery. In our studies segment-scale sediment production is measured with sediment fences, while detailed road surveys are used to assess road-stream connectivity and estimating the contribution of roads to watershed-scale sediment yields. Road-induced mass movements are not included here. Our mean road sediment production rates range from 0.1 kg m-2 yr-1 in snow-dominated areas in California's Sierra Nevada to 3.5 kg m-2 yr-1 in Colorado and 7.4 kg m-2 yr-1 on St. John in the Caribbean. First-order controls on road sediment production are the amount and type of precipitation, road gradient, road surface area, and surface cover, although geology and soil type also can be important. Higher traffic levels can greatly increase road sediment production by reducing the amount of surface cover, increasing the supply of fine sediment, and increasing the propensity for rilling, particularly during wet weather. Applying gravel can reduce road sediment production by a factor of 2-8 times by largely eliminating rainsplash and reducing rilling. Grading will at least double road sediment production by increasing the supply of easily erodible fine particles. The percent of road length connected to streams also varies widely. In California only 3% of the road length was connected in a snow-dominated area as opposed to 30% in a nearby rain

  15. Protodeboronation of Heteroaromatic, Vinyl, and Cyclopropyl Boronic Acids: pH-Rate Profiles, Autocatalysis, and Disproportionation.

    PubMed

    Cox, Paul A; Leach, Andrew G; Campbell, Andrew D; Lloyd-Jones, Guy C

    2016-07-27

    pH-rate profiles for aqueous-organic protodeboronation of 18 boronic acids, many widely viewed as unstable, have been studied by NMR and DFT. Rates were pH-dependent, and varied substantially between the boronic acids, with rate maxima that varied over 6 orders of magnitude. A mechanistic model containing five general pathways (k1-k5) has been developed, and together with input of [B]tot, KW, Ka, and KaH, the protodeboronation kinetics can be correlated as a function of pH (1-13) for all 18 species. Cyclopropyl and vinyl boronic acids undergo very slow protodeboronation, as do 3- and 4-pyridyl boronic acids (t0.5 > 1 week, pH 12, 70 °C). In contrast, 2-pyridyl and 5-thiazolyl boronic acids undergo rapid protodeboronation (t0.5 ≈ 25-50 s, pH 7, 70 °C), via fragmentation of zwitterionic intermediates. Lewis acid additives (e.g., Cu, Zn salts) can attenuate (2-pyridyl) or accelerate (5-thiazolyl and 5-pyrazolyl) fragmentation. Two additional processes compete when the boronic acid and the boronate are present in sufficient proportions (pH = pKa ± 1.6): (i) self-/autocatalysis and (ii) sequential disproportionations of boronic acid to borinic acid and borane. PMID:27355973

  16. Deglacial diatom production in the tropical North Atlantic driven by enhanced silicic acid supply

    NASA Astrophysics Data System (ADS)

    Hendry, Katharine R.; Gong, Xun; Knorr, Gregor; Pike, Jennifer; Hall, Ian R.

    2016-03-01

    Major shifts in ocean circulation are thought to be responsible for abrupt changes in temperature and atmospheric CO2 during the last deglaciation, linked to variability in meridional heat transport and deep ocean carbon storage. There is also widespread evidence for shifts in biological production during these times of deglacial CO2 rise, including enhanced diatom production in regions such as the tropical Atlantic. However, it remains unclear as to whether this diatom production was driven by enhanced wind-driven upwelling or density-driven vertical mixing, or by elevated thermocline concentrations of silicic acid supplied to the surface at a constant rate. Here, we demonstrate that silicic acid supply at depth in the NE Atlantic was enhanced during the abrupt climate events of the deglaciation. We use marine sediment archives to show that an increase in diatom production during abrupt climate shifts could only occur in regions of the NE Atlantic where the deep supply of silicic acid could reach the surface. The associated changes are indicative of enhanced regional wind-driven upwelling and/or weakened stratification due to circulation changes during phases of weakened Atlantic meridional overturning. Globally near-synchronous pulses of diatom production and enhanced thermocline concentrations of silicic acid suggest that widespread deglacial surface-driven breakdown of stratification, linked to changes in atmospheric circulation, had major consequences for biological productivity and carbon cycling.

  17. Physiological heterogeneity of Pseudomonas taetrolens during lactobionic acid production.

    PubMed

    Alonso, Saúl; Rendueles, Manuel; Díaz, Mario

    2012-12-01

    Physiological heterogeneity constitutes a critical parameter in biotechnological systems since both metabolite yield and productivity are often hampered by the presence of undesired physiological cell subpopulations. In the present study, the physiological status and functionality of Pseudomonas taetrolens cells were monitored by multiparameter flow cytometry during fermentative lactobionic acid production at the shake-flask and bioreactor scale. In shake-flask fermentation, the onset of the lactobionic acid production phase was accompanied by a progressive loss of cellular metabolic activity, membrane polarization, and membrane integrity concomitantly to acidification. In fact, population dynamics has shown the prevalence of damaged and dead subpopulations when submitted to a pH < 4 from 16 h onwards. Furthermore, fluorescence-activated cell sorting revealed that these sublethally injured cells were nonculturable. In contrast, P. taetrolens cells exhibited a robust physiological status during bioreactor cultivations performed with a pH-shifted strategy at 6.5, remaining predominantly healthy and metabolically active (>96 %) as well as maintaining bioconversion efficiency throughout the course of the fermentation. Additionally, an assessment of the seed culture's physiological robustness was carried out in order to determine the best seed culture age. Results showed that bioreactor culture performance, growth, and lactobionic acid production efficiency were strongly dependent on the physiological heterogeneity displayed by the seed culture. This study provides the most suitable criteria for optimizing lactobionic acid production efficiency through a novel flow cytometric-based approach based on the physiological status of P. taetrolens. It also constitutes a valuable, broad-ranging methodology for the enhancement of microbial bioprocesses involved in the production of secondary metabolites. PMID:22777280

  18. Measurement of Fatty Acid Oxidation Rates in Animal Tissues and Cell Lines

    PubMed Central

    Huynh, Frank K.; Green, Michelle F.; Koves, Timothy R.; Hirschey, Matthew D.

    2014-01-01

    While much oncological research has focused on metabolic shifts in glucose and amino acid oxidation, recent evidence suggests that fatty acid oxidation (FAO) may also play an important role in the metabolic reprogramming of cancer cells. Here, we present a simple method for measuring FAO rates using radiolabeled palmitate, common laboratory reagents, and standard supplies. This protocol is broadly applicable for measuring FAO rates in cultured cancer cells as well as in both malignant and nontransformed animal tissues. PMID:24862277

  19. Enhanced production of docosahexaenoic acid in mammalian cells.

    PubMed

    Zhu, Guiming; Jiang, Xudong; Ou, Qin; Zhang, Tao; Wang, Mingfu; Sun, Guozhi; Wang, Zhao; Sun, Jie; Ge, Tangdong

    2014-01-01

    Docosahexaenoic acid (DHA), one of the important polyunsaturated fatty acids (PUFA) with pharmaceutical and nutraceutical effects, may be obtained through diet or synthesized in vivo from dietary a-linolenic acid (ALA). However, the accumulation of DHA in human body or other mammals relies on the intake of high dose of DHA for a certain period of time, and the bioconversion of dietary ALA to DHA is very limited. Therefore the mammalian cells are not rich in DHA. Here, we report a new technology for increased production of DHA in mammalian cells. By using transient transfection method, Siganus canaliculatus Δ4 desaturase was heterologously expressed in chinese hamster ovary (CHO) cells, and simultaneously, mouse Δ6-desaturase and Δ5-desaturase were overexpressed. The results demonstrated that the overexpression of Δ6/Δ5-desaturases significantly enhanced the ability of transfected cells to convert the added ALA to docosapentaenoic acid (DPA) which in turn get converted into DHA directly and efficiently by the heterologously expressed Δ4 desaturase. This technology provides the basis for potential utility of these gene constructs in the creation of transgenic livestock for increased production of DHA/related products to meet the growing demand of this important PUFA. PMID:24788769

  20. A novel cleaner production process of citric acid by recycling its treated wastewater.

    PubMed

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Zhang, Hong-Jian; Zeng, Xin; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2016-07-01

    In this study, a novel cleaner production process of citric acid was proposed to completely solve the problem of wastewater management in citric acid industry. In the process, wastewater from citric acid fermentation was used to produce methane through anaerobic digestion and then the anaerobic digestion effluent was further treated with air stripping and electrodialysis before recycled as process water for the later citric acid fermentation. This proposed process was performed for 10 batches and the average citric acid production in recycling batches was 142.4±2.1g/L which was comparable to that with tap water (141.6g/L). Anaerobic digestion was also efficient and stable in operation. The average chemical oxygen demand (COD) removal rate was 95.1±1.2% and methane yield approached to 297.7±19.8mL/g TCODremoved. In conclusion, this novel process minimized the wastewater discharge and achieved the cleaner production in citric acid industry. PMID:27054882

  1. The effect of temperature on L-lactic acid production and metabolite distribution of Lactobacillus casei.

    PubMed

    Qin, Hao; Gong, Sai-Sai; Ge, Xiang-Yang; Zhang, Wei-Guo

    2012-01-01

    The effect of temperature on the growth and L-lactic acid production of Lactobacillus casei G-03 was investigated in a 7-L bioreactor. It was found that the maximum specific growth rate (0.27 hr⁻¹) and L-lactic acid concentration (160.2 g L⁻¹) were obtained at a temperature of 41°C. Meanwhile, the maximum L-lactic acid yield, productivity, and dry cell weight were up to 94.1%, 4.44 g L⁻¹ hr⁻¹, and 4.30 g L⁻¹, respectively. At lower or higher temperature, the Lactobacillus casei G-03 showed lower acid production and biomass. Moreover, the main metabolite distribution of strain G-03 response to variations in temperatures was studied. The results suggested that temperature has a remarkable effect on metabolite distribution, and the maximum carbon flux toward lactic acid at the pyruvate node was obtained at 41°C, which had the minimum carbon flux toward acetic acid. PMID:23030467

  2. Production of p-hydroxybenzoic acid from p-coumaric acid by Burkholderia glumae BGR1.

    PubMed

    Jung, Da-Hye; Kim, Eun-Jung; Jung, Eunok; Kazlauskas, Romas J; Choi, Kwon-Young; Kim, Byung-Gee

    2016-07-01

    p-Coumaric acid (pCA) is abundant in biomass with low lignin content, such as straw and stubble from rye, wheat, and barley. pCA can be isolated from biomass and used for the synthesis of aromatic hydrocarbons. Here, we report engineering of the natural pathway for conversion of pCA into p-hydroxybenzoic acid (pHBA) to increase the amount of pHBA that accumulates more than 100-fold. Burkholderia glumae strain BGR1 (BGR1) grows efficiently on pCA as a sole carbon source via a CoA-dependent non-β-oxidation pathway. This pathway removes two carbons from pCA as acetyl-CoA yielding p-hydroxybenzaldehyde and subsequently oxidizes it to pHBA. To increase the amount of accumulated pHBA in BGR1, we first deleted two genes encoding enzymes that degrade pHBA in the β-ketoadipate pathway. At 10 mM of pCA, the double deletion mutant BGR1_PB4 (Δphb3hΔbcl) accumulated pHBA with 95% conversion, while the control BGR1 accumulated only with 11.2% conversion. When a packed bed reactor containing immobilized BGR1_PB4 cells was operated at a dilution rate 0.2 h(-1) , the productivity of pHBA was achieved at 9.27 mg/L/h for 134 h. However, in a batch reactor at 20 mM pCA, growth of BGR1_PB4 was strongly inhibited, resulting in a low conversion of 19.3%. To further increase the amount of accumulated pCA, we identified the first enzyme in the pathway, p-hydroxcinnmaoyl-CoA synthetase II (phcs II), as the rate-limiting enzyme. Over expression of phcs II using a Palk promoter in a batch reaction at 20 mM of pCA yielded 99.0% conversion to pHBA, which is the highest concentration of pHBA ever reported using a biological process. Biotechnol. Bioeng. 2016;113: 1493-1503. © 2015 Wiley Periodicals, Inc. PMID:26693833

  3. Pair production rates in mildly relativistic, magnetized plasmas

    NASA Technical Reports Server (NTRS)

    Burns, M. L.; Harding, A. K.

    1984-01-01

    Electron-positron pairs may be produced by either one or two photons in the presence of a strong magnetic field. In magnetized plasmas with temperatures kT approximately sq mc, both of these processes may be important and could be competitive. The rates of one-photon and two-photon pair production by photons with Maxwellian, thermal bremsstrahlung, thermal synchrotron and power law spectra are calculated as a function of temperature or power law index and field strength. This allows a comparison of the two rates and a determination of the conditions under which each process may be a significant source of pairs in astrophysical plasmas. It is found that for photon densities n(gamma) or = 10 to the 25th power/cu cm and magnetic field strengths B or = 10 to the 12th power G, one-photon pair production dominates at kT approximately sq mc for a Maxwellian, at kT approximately 2 sq mc for a thermal bremsstrahlung spectrum, at all temperatures for a thermal synchrotron spectrum, and for power law spectra with indices s approximately 4.

  4. Variations of cosmogenic radionuclide production rates along the meteorite orbits

    NASA Astrophysics Data System (ADS)

    Alexeev, V. A.; Laubenstein, M.; Povinec, P. P.; Ustinova, G. K.

    2015-08-01

    Cosmogenic radionuclides produced by galactic cosmic rays (GCR) in meteorites during their motion in space are natural detectors of the GCR intensity and variations along the meteorite orbits. On the basis of measured and calculated contents of cosmogenic radionuclides in the freshly fallen Chelyabinsk and Košice chondrites some peculiarities of generation of cosmogenic radionuclides of different half-lives in the chondrites of different orbits and dates of fall onto the Earth are demonstrated. Dependence of production rates of the radionuclides on the GCR variations in the heliosphere is analyzed. Using radionuclides with different half-lives it is possible to compare the average GCR intensity over various time periods. The measurement and theoretical analysis of cosmogenic radionuclides in consecutively fallen chondrites provide a unique information on the space-time continuum of the cosmogenic radionuclide production rates and their variations over a long time scale, which could be useful in correlative analyses of processes in the heliosphere. Some applications of cosmogenic radionuclide depth distribution in chondrites for estimation of their pre-atmospheric sizes are illustrated.

  5. [The important role of vitamins in the over-production of pyruvic acid].

    PubMed

    Li, Y; Chen, J; Lun, S; Rui, X

    2000-10-01

    The effect of nicotinic acid, thiamine, pyridoxine, biotin and riboflavin on the production of pyruvic acid by Torulopsis glabrata WSH-IP303 with glucose as carbon source and NH4Cl as sole nitrogen source was investigated. By using orthogonal experiment method, thiamine was confirmed to be the most important factor affecting the production of pyruvic acid. Based on a certain concentration range of thiamine (0.01-0.015 mg/L), glucose consumption rate can be enhanced by increasing the concentration of nicotinic acid. When the concentration of nicotinic acid, thiamine, pyridoxine, biotin and riboflavin were 8, 0.015, 0.4, 0.04 and 0.1 mg/L, respectively, the concentration and yield to glucose of pyruvic acid reached 52.4 g/L and 0.525 g/g at 48 h in flask culture, respectively. Batch culture was conducted in a 2.5 L fermentor with initial glucose concentration of 120 g/L. By adopting the optimal concentration combination of vitamins, the concentration and yield to glucose of pyruvic acid reached 69.4 g/L and 0.593 g/g at 57.5 h, which were increased by 32.4% and 13% than the best results in flask culture, respectively. PMID:12548766

  6. Valproic Acid Induces Antimicrobial Compound Production in Doratomyces microspores

    PubMed Central

    Zutz, Christoph; Bacher, Markus; Parich, Alexandra; Kluger, Bernhard; Gacek-Matthews, Agnieszka; Schuhmacher, Rainer; Wagner, Martin; Rychli, Kathrin; Strauss, Joseph

    2016-01-01

    One of the biggest challenges in public health is the rising number of antibiotic resistant pathogens and the lack of novel antibiotics. In recent years there is a rising focus on fungi as sources of antimicrobial compounds due to their ability to produce a large variety of bioactive compounds and the observation that virtually every fungus may still contain yet unknown so called “cryptic,” often silenced, compounds. These putative metabolites could include novel bioactive compounds. Considerable effort is spent on methods to induce production of these “cryptic” metabolites. One approach is the use of small molecule effectors, potentially influencing chromatin landscape in fungi. We observed that the supernatant of the fungus Doratomyces (D.) microsporus treated with valproic acid (VPA) displayed antimicrobial activity against Staphylococcus (S.) aureus and two methicillin resistant clinical S. aureus isolates. VPA treatment resulted in enhanced production of seven antimicrobial compounds: cyclo-(L-proline-L-methionine) (cPM), p-hydroxybenzaldehyde, cyclo-(phenylalanine-proline) (cFP), indole-3-carboxylic acid, phenylacetic acid (PAA) and indole-3-acetic acid. The production of the antimicrobial compound phenyllactic acid was exclusively detectable after VPA treatment. Furthermore three compounds, cPM, cFP, and PAA, were able to boost the antimicrobial activity of other antimicrobial compounds. cPM, for the first time isolated from fungi, and to a lesser extent PAA, are even able to decrease the minimal inhibitory concentration of ampicillin in MRSA strains. In conclusion we could show in this study that VPA treatment is a potent tool for induction of “cryptic” antimicrobial compound production in fungi, and that the induced compounds are not exclusively linked to the secondary metabolism. Furthermore this is the first discovery of the rare diketopiperazine cPM in fungi. Additionally we could demonstrate that cPM and PAA boost antibiotic activity

  7. New Acid Stimulation Treatment to Sustain Production - Los Angeles Downtown Oil Field

    SciTech Connect

    Russell, Richard C.

    2003-03-10

    Hydrochloric acid stimulation was successfully used on several wells in the Los Angeles Downtown Field, in the past. The decline rates after stimulation were relatively high and generally within six months to a year, production rates have returned to their prestimulation rates. The wells in Los Angeles Downtown Field have strong scale producing tendencies and many wells are treated for scale control. Four wells were carefully selected that are representative of wells that had a tendency to form calcium carbonate scale and had shown substantial decline over the last few years.

  8. Natural Product Anacardic Acid from Cashew Nut Shells Stimulates Neutrophil Extracellular Trap Production and Bactericidal Activity.

    PubMed

    Hollands, Andrew; Corriden, Ross; Gysler, Gabriela; Dahesh, Samira; Olson, Joshua; Raza Ali, Syed; Kunkel, Maya T; Lin, Ann E; Forli, Stefano; Newton, Alexandra C; Kumar, Geetha B; Nair, Bipin G; Perry, J Jefferson P; Nizet, Victor

    2016-07-01

    Emerging antibiotic resistance among pathogenic bacteria is an issue of great clinical importance, and new approaches to therapy are urgently needed. Anacardic acid, the primary active component of cashew nut shell extract, is a natural product used in the treatment of a variety of medical conditions, including infectious abscesses. Here, we investigate the effects of this natural product on the function of human neutrophils. We find that anacardic acid stimulates the production of reactive oxygen species and neutrophil extracellular traps, two mechanisms utilized by neutrophils to kill invading bacteria. Molecular modeling and pharmacological inhibitor studies suggest anacardic acid stimulation of neutrophils occurs in a PI3K-dependent manner through activation of surface-expressed G protein-coupled sphingosine-1-phosphate receptors. Neutrophil extracellular traps produced in response to anacardic acid are bactericidal and complement select direct antimicrobial activities of the compound. PMID:27226531

  9. A fluidized-bed continuous bioreactor for lactic acid production

    SciTech Connect

    Andrews, G.F.; Fonta, J.P.

    1988-05-01

    A laboratory bioreactor consists of a fluidized bed of monosized activated carbon coated with a biofilm of the homolactic fermentative organism Streptococcus thermophilus. Biofilm growth moves the carbon through the bed, and adsorption of substrate and product at the bottom and top of the bed respectively reduces their inhibitory effects on the organism. Theory shows that high reactor productivity and rapid recirculation of carbon through the bed require a biofilm thickness of 25 to 45% of the carbon particle radius on particles fed into the base of the bed. This could not be achieved in practice due to the fragility of the biofilm. Product concentration was higher than expected from measurements of product inhibition, possibly because it is the undissociated form of the acid that both inhibits metabolism and adsorbs on the activated carbon. The observed productivity of 12 gm/1 hr could be greatly increased by ph control. 13 refs., 7 figs., 2 tabs.

  10. Succinic acid production from acid hydrolysate of corn fiber by Actinobacillus succinogenes.

    PubMed

    Chen, Kequan; Jiang, Min; Wei, Ping; Yao, Jiaming; Wu, Hao

    2010-01-01

    Dilute acid hydrolysate of corn fiber was used as carbon source for the production of succinic acid by Actinobacillus succinogenes NJ113. The optimized hydrolysis conditions were obtained by orthogonal experiments. When corn fiber particles were of 20 mesh in size and treated with 1.0% sulfuric acid at 121 degrees C for 2 h, the total sugar yield could reach 63.3%. It was found that CaCO(3) neutralization combined with activated carbon adsorption was an effective method to remove fermentation inhibitors especially furfural that presented in the acid hydrolysate of corn fiber. Only 5.2% of the total sugar was lost, while 91.9% of furfural was removed. The yield of succinic acid was higher than 72.0% with the detoxified corn fiber hydrolysate as the carbon source in anaerobic bottles or 7.5 L fermentor cultures. It was proved that the corn fiber hydrolysate could be an alternative to glucose for the production of succinic acid by A. succinogenes NJ113. PMID:18830824

  11. Biodiesel from wastewater: lipid production in high rate algal pond receiving disinfected effluent.

    PubMed

    Assemany, Paula Peixoto; Calijuri, Maria Lucia; do Couto, Eduardo de Aguiar; Santiago, Aníbal Fonseca; Dos Reis, Alberto José Delgado

    2015-01-01

    The production of different species of microalgae in consortium with other micro-organisms from wastewaters may represent an alternative process, to reduce the costs, for obtaining biofuels. The aim of this study was to evaluate the influence of pre-ultraviolet disinfection (UV) in the production of lipids from biomass produced in high rate ponds. Two high rate algal ponds were evaluated: a pond that received domestic sewage without disinfection and the other receiving domestic sewage previously disinfected by UV radiation (uvHRAP). The UV disinfection did not lead to significant differences in fatty acid profile and total lipid productivities, although it increased algal biomass concentration and productivity as well as lipid content. Moreover, the overall biomass concentrations and productivities decreased with the UV disinfection, mostly as a consequence of a loss in bacterial load. We thus conclude that uvHRAP disinfection may represent a potential strategy to promote the cleaner and safer growth of algal biomass when cultivated in consortium with other micro-organisms. Mainly regarding the use of wastewater as culture medium, together with a cheaper production of lipids for biodiesel, pre-disinfection may represent an advance since extraction costs could be significantly trimmed due to the increase in lipid content. PMID:25909734

  12. Environmental evaluation of eicosapentaenoic acid production by Phaeodactylum tricornutum.

    PubMed

    Pérez-López, Paula; González-García, Sara; Allewaert, Céline; Verween, Annick; Murray, Patrick; Feijoo, Gumersindo; Moreira, Ma Teresa

    2014-01-01

    Polyunsaturated fatty acids (PUFAs) play an important role in human health. Due to the increased market demand, the production of PUFAs from potential alternative sources such as microalgae is receiving increased interest. The aim of this study was to perform a life cycle assessment (LCA) of the biotechnological production of eicosapentaenoic acid (EPA) from the marine diatom Phaeodactylum tricornutum, followed by the identification of avenues to improve its environmental profile. The LCA tackles two production schemes of P. tricornutum PUFAs with an EPA content of 36%: lab and pilot scales. The results at lab scale show that both the electricity requirements and the production of the extraction agent (chloroform) have significant influence on the life cycle environmental performance of microalgal EPA production. An alternative method based on hexane was proposed to replace chloroform and environmental benefits were identified. Regarding the production of EPA at pilot scale, three main environmental factors were identified: the production of the nitrogen source required for microalgae growing, the transport activities and electricity requirements. Improvement alternatives were proposed and discussed concerning: a) the use of nitrogen based fertilizers, b) the valorization of the residual algal paste as soil conditioner and, c) the anaerobic digestion of the residual algal paste for bioenergy production. Encouraging environmental benefits could be achieved if sodium nitrate was substituted by urea, calcium nitrate or ammonium nitrate, regardless the category under assessment. In contrast, minor improvement was found when valorizing the residual algal paste as mineral fertilizer, due to its overall low content in N and P. Concerning the biogas production from the anaerobic digestion, the improvement on the environmental profile was also limited due to the discrepancy between the potential energy production from the algal paste and the high electricity requirements in

  13. 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.

  14. Carboxylic acid production from brewer's spent grain via mixed culture fermentation.

    PubMed

    Liang, Shaobo; Wan, Caixia

    2015-04-01

    This study aimed at investigating carboxylic acid production from brewer's spent grain (BSG) via mixed culture fermentation. The results showed that the distribution of fermentation products was significantly affected by pH conditions and the addition of electron donors. Lactic acid was the dominant component under acidic and alkaline conditions while volatile fatty acids (VFAs) became dominant under the neutral condition. Furthermore, the neutral condition favored the chain elongation of carboxylic acids, especially with ethanol as the electron donor. Ethanol addition enhanced valeric acid and caproic acid production by 44% and 167%, respectively. Lactic acid addition also had positive effects on VFAs production under the neutral condition but limited to C2-C4 products. As a result, propionic acid and butyric acid production was increased by 109% and 152%, respectively. These findings provide substantial evidence for regulating carboxylic acid production during mixed culture fermentation of BSG by controlling pH and adding electron donors. PMID:25698409

  15. Lactide Synthesis and Chirality Control for Polylactic acid Production.

    PubMed

    Van Wouwe, Pieter; Dusselier, Michiel; Vanleeuw, Evelien; Sels, Bert

    2016-05-10

    Polylactic acid (PLA) is a very promising biodegradable, renewable, and biocompatible polymer. Aside from its production, its application field is also increasing, with use not only in commodity applications but also as durables and in biomedicine. In the current PLA production scheme, the most expensive part is not the polymerization itself but obtaining the building blocks lactic acid (LA) and lactide, the actual cyclic monomer for polymerization. Although the synthesis of LA and the polymerization have been studied systematically, reports of lactide synthesis are scarce. Most lactide synthesis methods are described in patent literature, and current energy-intensive, aselective industrial processes are based on archaic scientific literature. This Review, therefore, highlights new methods with a technical comparison and description of the different approaches. Water-removal methodologies are compared, as this is a crucial factor in PLA production. Apart from the synthesis of lactide, this Review also emphasizes the use of chemically produced racemic lactic acid (esters) as a starting point in the PLA production scheme. Stereochemically tailored PLA can be produced according to such a strategy, giving access to various polymer properties. PMID:27071863

  16. 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

  17. 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

  18. Technology and economic assessment of lactic acid production and uses

    SciTech Connect

    Datta, R.; Tsai, S.P.

    1996-03-01

    Lactic acid has been an intermediate-volume specialty chemical (world production {approximately}50,000 tons/yr) used in a wide range of food-processing and industrial applications. Potentially, it can become a very large-volume, commodity-chemical intermediate produced from carbohydrates for feedstocks of biodegradable polymers, oxygenated chemicals, environmentally friendly ``green`` solvents, and other intermediates. In the past, efficient and economical technologies for the recovery and purification of lactic acid from fermentation broths and its conversion to the chemical or polymer intermediates had been the key technology impediments and main process cost centers. Development and deployment of novel separations technologies, such as electrodialysis with bipolar membranes, extractive and catalytic distillations, and chemical conversion, can enable low-cost production with continuous processes in large-scale operations. The emerging technologies can use environmentally sound lactic acid processes to produce environmentally useful products, with attractive process economics. These technology advances and recent product and process commercialization strategies are reviewed and assessed.

  19. Bio-based production of organic acids with Corynebacterium glutamicum

    PubMed Central

    Wieschalka, Stefan; Blombach, Bastian; Bott, Michael; Eikmanns, Bernhard J

    2013-01-01

    The shortage of oil resources, the steadily rising oil prices and the impact of its use on the environment evokes an increasing political, industrial and technical interest for development of safe and efficient processes for the production of chemicals from renewable biomass. Thus, microbial fermentation of renewable feedstocks found its way in white biotechnology, complementing more and more traditional crude oil-based chemical processes. Rational strain design of appropriate microorganisms has become possible due to steadily increasing knowledge on metabolism and pathway regulation of industrially relevant organisms and, aside from process engineering and optimization, has an outstanding impact on improving the performance of such hosts. Corynebacterium glutamicum is well known as workhorse for the industrial production of numerous amino acids. However, recent studies also explored the usefulness of this organism for the production of several organic acids and great efforts have been made for improvement of the performance. This review summarizes the current knowledge and recent achievements on metabolic engineering approaches to tailor C. glutamicum for the bio-based production of organic acids. We focus here on the fermentative production of pyruvate, l-and d-lactate, 2-ketoisovalerate, 2-ketoglutarate, and succinate. These organic acids represent a class of compounds with manifold application ranges, e.g. in pharmaceutical and cosmetics industry, as food additives, and economically very interesting, as precursors for a variety of bulk chemicals and commercially important polymers. Funding Information Work in the laboratories of the authors was supported by the Fachagentur Nachwachsende Rohstoffe (FNR) of the Bundesministerium für Ernährung, Landwirtschaft und Verbraucherschutz (BMELV; FNR Grants 220-095-08A and 220-095-08D; Bio-ProChemBB project, ERA-IB programme), by the Deutsche Bundesstiftung Umwelt (DBU Grant AZ13040/05) and the Evonik Degussa AG. PMID

  20. 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.

  1. Influence of polysorbate 80 and cyclopropane fatty acid synthase activity on lactic acid production by Lactobacillus casei ATCC 334 at low pH.

    PubMed

    Broadbent, J R; Oberg, T S; Hughes, J E; Ward, R E; Brighton, C; Welker, D L; Steele, J L

    2014-03-01

    Lactic acid is an important industrial chemical commonly produced through microbial fermentation. The efficiency of acid extraction is increased at or below the acid's pKa (pH 3.86), so there is interest in factors that allow for a reduced fermentation pH. We explored the role of cyclopropane synthase (Cfa) and polysorbate (Tween) 80 on acid production and membrane lipid composition in Lactobacillus casei ATCC 334 at low pH. Cells from wild-type and an ATCC 334 cfa knockout mutant were incubated in APT broth medium containing 3 % glucose plus 0.02 or 0.2 % Tween 80. The cultures were allowed to acidify the medium until it reached a target pH (4.5, 4.0, or 3.8), and then the pH was maintained by automatic addition of NH₄OH. Cells were collected at the midpoint of the fermentation for membrane lipid analysis, and media samples were analyzed for lactic and acetic acids when acid production had ceased. There were no significant differences in the quantity of lactic acid produced at different pH values by wild-type or mutant cells grown in APT, but the rate of acid production was reduced as pH declined. APT supplementation with 0.2 % Tween 80 significantly increased the amount of lactic acid produced by wild-type cells at pH 3.8, and the rate of acid production was modestly improved. This effect was not observed with the cfa mutant, which indicated Cfa activity and Tween 80 supplementation were each involved in the significant increase in lactic acid yield observed with wild-type L. casei at pH 3.8. PMID:24370881

  2. Control of product selectivity using solid acids for the catalytic addition of phenol to hydroxy fatty acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The acid catalyzed reactions of hydroxy fatty acids, such as ricinoleic and lesquerolic, in the presence of phenolics can lead to four products or product groups. These include simple dehydration to dienoic acids, cyclization to epoxides, Friedel-Crafts alkylations of the double bonds, or ether for...

  3. 40 CFR 721.10664 - Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., reaction products with alkenoic acid alkyl esters and diamine (generic). 721.10664 Section 721.10664... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10664 Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic)....

  4. 40 CFR 721.10664 - Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., reaction products with alkenoic acid alkyl esters and diamine (generic). 721.10664 Section 721.10664... SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10664 Alkenedioic acid dialkyl ester, reaction products with alkenoic acid alkyl esters and diamine (generic)....

  5. Buyer-vendor coordination for fixed lifetime product with quantity discount under finite production rate

    NASA Astrophysics Data System (ADS)

    Zhang, Qinghong; Luo, Jianwen; Duan, Yongrui

    2016-03-01

    Buyer-vendor coordination has been widely addressed; however, the fixed lifetime of the product is seldom considered. In this paper, we study the coordination of an integrated production-inventory system with quantity discount for a fixed lifetime product under finite production rate and deterministic demand. We first derive the buyer's ordering policy and the vendor's production batch size in decentralised and centralised systems. We then compare the two systems and show the non-coordination of the ordering policies and the production batch sizes. To improve the supply chain efficiency, we propose quantity discount contract and prove that the contract can coordinate the buyer-vendor supply chain. Finally, we present analytically tractable solutions and give a numerical example to illustrate the benefits of the proposed quantity discount strategy.

  6. 40 CFR 415.280 - Applicability; description of the boric acid production subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... boric acid production subcategory. 415.280 Section 415.280 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Boric Acid Production Subcategory § 415.280 Applicability; description of the boric acid... production of boric acid from ore-mined borax and from borax produced by the Trona process....

  7. Metabolic engineering in the biotechnological production of organic acids in the tricarboxylic acid cycle of microorganisms: Advances and prospects.

    PubMed

    Yin, Xian; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Liu, Long; Chen, Jian

    2015-11-01

    Organic acids, which are chemically synthesized, are also natural intermediates in the metabolic pathways of microorganisms, among which the tricarboxylic acid (TCA) cycle is the most crucial route existing in almost all living organisms. Organic acids in the TCA cycle include citric acid, α-ketoglutaric acid, succinic acid, fumaric acid, l-malic acid, and oxaloacetate, which are building-block chemicals with wide applications and huge markets. In this review, we summarize the synthesis pathways of these organic acids and review recent advances in metabolic engineering strategies that enhance organic acid production. We also propose further improvements for the production of organic acids with systems and synthetic biology-guided metabolic engineering strategies. PMID:25902192

  8. 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

  9. Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst.

    PubMed

    Long, Yun-Duo; Guo, Feng; Fang, Zhen; Tian, Xiao-Fei; Jiang, Li-Qun; Zhang, Fan

    2011-07-01

    Biodiesel and lactic acid from rapeseed oil was produced using sodium silicate as catalyst. The transesterification in the presence of the catalyst proceeded with a maximum yield of 99.6% under optimized conditions [3% (w/w) sodium silicate, methanol/oil molar ratio 9/1, reaction time 60 min, reaction temperature 60°C, and stirring rate 250 rpm]. After six consecutive transesterification reactions, the catalyst was collected and used for catalysis of the conversion of glycerol to lactic acid. A maximum yield of 80.5% was achieved when the reaction was carried out at a temperature of 300°C for 90 min. Thus, sodium silicate is an effective catalyst for transesterification and lactic acid production from the biodiesel by-product, glycerol. PMID:21530245

  10. Towards sustainable sources for omega-3 fatty acids production.

    PubMed

    Adarme-Vega, T Catalina; Thomas-Hall, Skye R; Schenk, Peer M

    2014-04-01

    Omega-3 fatty acids eicosapentaenoic acid (EPA) and docohexaenoic acid (DHA), provide significant health benefits for brain function/development and cardiovascular conditions. However, most EPA and DHA for human consumption is sourced from small fatty fish caught in coastal waters and, with depleting global fish stocks, recent research has been directed towards more sustainable sources. These include aquaculture with plant-based feeds, krill, marine microalgae, microalgae-like protists and genetically-modified plants. To meet the increasing demand for EPA and DHA, further developments are needed towards land-based sources. In particular large-scale cultivation of microalgae and plants is likely to become a reality with expected reductions in production costs, yield increasese and the adequate addressing of genetically modified food acceptance issues. PMID:24607804

  11. Spectral characterization of acid weathering products on Martian basaltic glass

    NASA Astrophysics Data System (ADS)

    Yant, Marcella; Rogers, A. Deanne; Nekvasil, Hanna; Zhao, Yu-Yan Sara; Bristow, Tom

    2016-03-01

    For the first time, direct infrared spectral analyses of glasses with Martian compositions, altered under controlled conditions, are presented in order to assess surface weathering and regolith development on Mars. Basaltic glasses of Irvine and Backstay composition were synthesized and altered using H2SO4-HCl acid solutions (pH 0-4). Scanning electron microscopy/energy dispersive spectroscopy, X-ray diffraction, Raman, and infrared spectral measurements were acquired for each reaction product. Infrared spectra were also acquired from previously synthesized and altered glasses with Pathfinder-measured compositions. Acid alteration on particles in the most acidic solutions (pH ≤ 1) yielded sulfate-dominated visible near infrared (VNIR) and thermal infrared (TIR) spectra with some silica influence. Spectral differences between alteration products from each starting material were present, reflecting strong sensitivity to changes in mineral assemblage. In the TIR, alteration features were preserved after reworking and consolidation. In the VNIR, hydrated sulfate features were present along with strong negative spectral slopes. Although such signatures are found in a few isolated locations on Mars with high-resolution spectrometers, much of the Martian surface lacks these characteristics, suggesting the following: acid alteration occurred at pH ≥ 2; small amounts of sulfates were reworked with unaltered material; there is a prevalence of intermediate-to-high silica glass in Martian starting materials (more resistant to acid alteration); primary or added sulfur were lacking; alteration features are obscured by dust; and/or large-scale, pervasive, acid sulfate weathering of the Martian surface did not occur. These results highlight the need to better understand the spectral properties of altered Martian surface material in order to enhance the interpretation of remote spectra for altered terrains.

  12. 50 CFR Table 3 to Part 679 - Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut 3 Table 3 to Part 679 Wildlife and Fisheries FISHERY... Rates for Groundfish Species and Conversion Rates for Pacific Halibut ER28JA02.074 ER10JY02.000...

  13. 50 CFR Table 3 to Part 679 - Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut 3 Table 3 to Part 679 Wildlife and Fisheries FISHERY... Rates for Groundfish Species and Conversion Rates for Pacific Halibut ER11JY11.007 ER11JY11.008...

  14. 50 CFR Table 3 to Part 679 - Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut 3 Table 3 to Part 679 Wildlife and Fisheries FISHERY... Rates for Groundfish Species and Conversion Rates for Pacific Halibut ER11JY11.007 ER11JY11.008...

  15. Formation rates, stability and reactivity of sulfuric acid - amine clusters predicted by computational chemistry

    NASA Astrophysics Data System (ADS)

    Kurtén, Theo; Ortega, Ismael; Kupiainen, Oona; Olenius, Tinja; Loukonen, Ville; Reiman, Heidi; McGrath, Matthew; Vehkamäki, Hanna

    2013-04-01

    Despite the importance of atmospheric particle formation for both climate and air quality, both experiments and non-empirical models using e.g. sulfuric acid, ammonia and water as condensing vapors have so far been unable to reproduce atmospheric observations using realistic trace gas concentrations. Recent experimental and theoretical evidence has shown that this mystery is likely resolved by amines. Combining first-principles evaporation rates for sulfuric acid - dimethylamine clusters with cluster kinetic modeling, we show that even sub-ppt concentrations of amines, together with atmospherically realistic concentrations of sulfuric acid, result in formation rates close to those observed in the atmosphere. Our simulated cluster formation rates are also close to, though somewhat larger than, those measured at the CLOUD experiment in CERN for both sulfuric acid - ammonia and sulfuric acid - dimethylamine systems. A sensitivity analysis indicates that the remaining discrepancy for the sulfuric acid - amine particle formation rates is likely caused by steric hindrances to cluster formation (due to alkyl groups of the amine molecules) rather than by significant errors in the evaporation rates. First-principles molecular dynamic and reaction kinetic modeling shed further light on the microscopic physics and chemistry of sulfuric acid - amine clusters. For example, while the number and type of hydrogen bonds in the clusters typically reach their equilibrium values on a picosecond timescale, and the overall bonding patterns predicted by traditional "static" quantum chemical calculations seem to be stable, the individual atoms participating in the hydrogen bonds continuously change at atmospherically realistic temperatures. From a chemical reactivity perspective, we have also discovered a surprising phenomenon: clustering with sulfuric acid molecules slightly increases the activation energy required for the abstraction of alkyl hydrogens from amine molecules. This implies

  16. Enhanced Production of Docosahexaenoic Acid in Mammalian Cells

    PubMed Central

    Zhu, Guiming; Jiang, Xudong; Ou, Qin; Zhang, Tao; Wang, Mingfu; Sun, Guozhi; Wang, Zhao; Sun, Jie; Ge, Tangdong

    2014-01-01

    Docosahexaenoic acid (DHA), one of the important polyunsaturated fatty acids (PUFA) with pharmaceutical and nutraceutical effects, may be obtained through diet or synthesized in vivo from dietary a-linolenic acid (ALA). However, the acumulation of DHA in human body or other mammals relies on the intake of high dose of DHA for a certain period of time, and the bioconversion of dietary ALA to DHA is very limited. Therefore the mammalian cells are not rich in DHA. Here, we report a new technology for increased prodution of DHA in mammalian cells. By using transient transfection method, Siganus canaliculatus Δ4 desaturase was heterologously expressed in chinese hamster ovary (CHO) cells, and simultaneously, mouse Δ6-desaturase and Δ5-desaturase were overexpressed. The results demonstrated that the overexpression of Δ6/Δ5-desaturases significantly enhanced the ability of transfected cells to convert the added ALA to docosapentaenoic acid (DPA) which in turn get converted into DHA directly and efficiently by the heterologously expressed Δ4 desaturase. This technology provides the basis for potential utility of these gene constructs in the creation of transgenic livestock for increased production of DHA/related products to meet the growing demand of this important PUFA. PMID:24788769

  17. Development of an industrializable fermentation process for propionic acid production.

    PubMed

    Stowers, Chris C; Cox, Brad M; Rodriguez, Brandon A

    2014-05-01

    Propionic acid (PA) is a short-chain fatty acid with wide industrial application including uses in pharmaceuticals, herbicides, cosmetics, and food preservatives. As a three-carbon building block, PA also has potential as a precursor for high-volume commodity chemicals such as propylene. Currently, most PA is manufactured through petrochemical routes, which can be tied to increasing prices and volatility due to difficulty in demand forecasting and feedstock availability. Herein described are research advancements to develop an industrially feasible, renewable route to PA. Seventeen Propionibacterium strains were screened using glucose and sucrose as the carbon source to identify the best platform strain. Propionibacterium acidipropionici ATCC 4875 was selected as the platform strain and subsequent fermentation optimization studies were performed to maximize productivity and yield. Fermentation productivity was improved three-fold to exceed 2 g/l/h by densifying the inoculum source. Byproduct levels, particularly lactic and succinic acid, were reduced by optimizing fermentor headspace pressure and shear. Following achievement of commercially viable productivities, the lab-grade medium components were replaced with industrial counterparts to further reduce fermentation costs. A pure enzymatically treated corn mash (ECM) medium improved the apparent PA yield to 0.6 g/g (PA produced/glucose consumed), but it came at the cost of reduced productivity. Supplementation of ECM with cyanocobalamin restored productivity to near lab-grade media levels. The optimized ECM recipe achieved a productivity of 0.5 g/l/h with an apparent PA yield of 0.60 g/g corresponding to a media cost <1 USD/kg of PA. These improvements significantly narrow the gap between the fermentation and incumbent petrochemical processes, which is estimated to have a manufacturing cost of 0.82 USD/kg in 2017. PMID:24627047

  18. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. II. ACID AND GENERAL BASE CATALYZED HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate acid and neutral hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition states of a ...

  19. Biosynthesis of Phosphonic and Phosphinic Acid Natural Products

    PubMed Central

    Metcalf, William W.; van der Donk, Wilfred A.

    2009-01-01

    Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lies behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin, and the clinical candidate for treatment of malaria FR900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations and a wealth of new biochemistry has been revealed through their study. These studies have also suggested new strategies for natural product discovery. PMID:19489722

  20. Hydrogen production rate from comet Austin 1982g

    NASA Technical Reports Server (NTRS)

    Shih, P.; Scherb, F.; Roesler, F. L.

    1984-01-01

    Meaningful measurements with respect to the cometary Balmer-alpha (H-alpha) emission are difficult and require the use of special equipment. The first ground-based observations of H-alpha emission from a cometary hydrogen corona were conducted on comet Kohoutek 1973 XII with a large-aperture Fabry-Perot spectrometer installed at the McMath solar telescope at Kitt Peak National Observatory. The present investigation is concerned with the second ground-based observations of cometary H-alpha emission carried out during the apparition of comet Austin 1982g. A 150 mm dual-etalon Fabry-Perot spectrometer was employed in the experiment. Use was made of an observatory which is designed for the high spectral resolution study of faint extended sources such as interstellar and geocoronal emission lines. The investigation demonstrates that hydrogen production rates from comets as faint as about 7th magnitude can be routinely measured from the ground at minimal cost.

  1. Production rates of terrestrial in-situ-produced cosmogenic nuclides

    SciTech Connect

    Reedy, R.C.; Tuniz, C.; Fink, D.

    1993-12-31

    Production rates of cosmogenic nuclides made in situ in terrestrial samples and how they are applied to the interpretation of measured radionuclide concentrations were discussed at a one-day Workshop held 2 October 1993 in Sydney, Australia. The status of terrestrial in-situ studies using the long-lived radionuclides {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, and {sup 41}Ca and of various modeling and related studies were presented. The relative uncertainties in the various factors that go into the interpretation of these terrestrial in-situ cosmogenic nuclides were discussed. The magnitudes of the errors for these factors were estimated and none dominated the final uncertainty.

  2. Production of oxalic acid from sugar beet molasses by formed nitrogen oxides.

    PubMed

    Gürü, M; Bilgesü, A Y; Pamuk, V

    2001-03-01

    Production of oxalic acid from sugar beet molasses was developed in a series of three reactors. Nitrogen oxides formed were used to manufacture oxalic acid in the second and third reactor. Parameters affecting the reaction were determined to be, air flow rate, temperature, the amount of V2O5 catalyst and the concentrations of molasses and H2SO4. The maximum yields in the second and third reactors were 78.9% and 74.6% of theoretical yield, respectively. Also, kinetic experiments were performed and the first-order rate constants were determined for the glucose consumption rate. Nitrogen oxides in off-gases from the final reactor were absorbed in water and concentrated sulphuric acid and reused in the following reactors giving slightly lower yields under similar conditions. In this novel way, it was possible to recover NO(x) and to prevent air pollution. Meanwhile, it was possible to reduce the unit cost of reactant for oxalic acid production. A maximum 77.5% and 74.1% of theoretical yield was obtained by using the absorption solutions with NO(x). PMID:11211079

  3. The effect of limestone treatments on the rate of acid generation from pyritic mine gangue.

    PubMed

    Burt, R A; Caruccio, F T

    1986-09-01

    Surface water enters the Haile Gold Mine, Lancaster County, South Carolina by means of a small stream and is ponded behind a dam and in an abandoned pit. This water is affected by acidic drainage. In spite of the large exposures of potentially acid producing pyritic rock, the flux of acid to the water is relatively low. Nevertheless, the resulting pH values of the mine water are low (around 3.5) due to negligible buffering capacity. In view of the observed low release of acidity, the potential for acid drainage abatement by limestone ameliorants appears feasible.This study investigated the effects of limestone treatment on acid generation rates of the Haile mine pyritic rocks through a series of leaching experiments. Below a critical alkalinity threshold value, solutions of dissolved limestone were found consistently to accelerate the rate of pyrite oxidation by varying degrees. The oxidation rates were further accelerated by admixing solid limestone with the pyritic rock. However, after a period of about a month, the pyrite oxidation rate of the admixed samples declined to a level lower than that of untreated pyrite. Leachates produced by the pyrite and limestone mixtures contained little if any iron. Further, in the mixtures, an alteration of the pyrite surface was apparent.The observed behaviour of the treated pyrite appears to be related to the immersion of the pyrite grains within a high alkalinity/high pH environment. The high pH increases the rate of oxidation of ferrous iron which results in a higher concentration of ferric iron at the pyrite surface. This, in turn, increases the rate of pyrite oxidation. Above a threshold alkalinity value, the precipitation of hydrous iron oxides at the pyrite surface eventually outpaces acid generation and coats the pyrite surface, retarding the rate of pyrite oxidation. PMID:24214013

  4. Freely expanding detonation products: Scaling of rate processes

    NASA Astrophysics Data System (ADS)

    Greiner, N. R.

    1988-03-01

    Using the Los Alamos reactive hydrodynamics code KIVA, calculations have been made to simulate the free expansion of cylinders of detonation products into a high vacuum. The emphasis of this paper is on the scaling of rate processes with cylinder size and initial conditions as a function of position in the expanding mass. The processes considered include diffusion, unimolecular decomposition, biomolecular radical reactions, and vibrational relaxation. The calculations also give time-dependent velocity fields; schlieren images; and profiles of density, pressure, and temperature. Many features of the calculations can be compared with experimental observations, including time-delayed schlieren and shadowgraph snapshots, time-dependent absorption spectra, and time-of-arrival profiles of molecular species. Some unexpected insights, such as the effect of the equation of state on the shape of the expanding plume and the effect of position on the rate of quenching, are discussed. These calculations are being used to interpret the available experimental data and to design future experiments.

  5. Recent developments in cosmogenic nuclide production rate scaling

    NASA Astrophysics Data System (ADS)

    Lifton, N. A.

    2013-12-01

    A new cosmogenic nuclide production rate scaling model based on analytical fits to Monte Carlo simulations of atmospheric cosmic ray flux spectra (both of which agree well with measured spectra) enables identification and quantification of the biases in previously published models (Lifton, N., Sato, T., Dunai, T., in review, Earth and Planet. Sci. Lett.). Scaling predictions derived from the new model (termed LSD) suggest two potential sources of bias in the previous models: different energy responses of the secondary neutron detectors used in developing the models, and different geomagnetic parameterizations. In addition, the particle flux spectra generated by the LSD model allow one to generate nuclide-specific scaling factors that reflect the influences of the flux energy distribution and the relevant excitation functions (probability of nuclide production in a given nuclear reaction as a function of energy). Resulting scaling factors indicate 3He shows the strongest positive deviation from the flux-based scaling, while 14C exhibits a negative deviation. These results are consistent with previous studies showing an increasing 3He/10Be ratio with altitude in the Himalayas, but with a much lower magnitude for the effect. Furthermore, the new model provides a flexible framework for exploring the implications of future advances in model inputs. For example, the effects of recently updated paleomagnetic models (e.g. Korte et al., 2011, Earth and Planet Sci. Lett. 312, 497-505) on scaling predictions will also be presented.

  6. Development of a real-time bioprocess monitoring method for docosahexaenoic acid production by Schizochytrium sp.

    PubMed

    Guo, Dong-Sheng; Ji, Xiao-Jun; Ren, Lu-Jing; Li, Gan-Lu; Yin, Feng-Wei; Huang, He

    2016-09-01

    Oxygen uptake rate (OUR) and respiratory quotient (RQ) are key respiratory parameters for docosahexaenoic acid (DHA) production by Schizochytrium sp. HX-308 under dissolved oxygen limited conditions. To investigate the relationship of OUR and RQ with culture status, three independent cultures with different aeration rates were performed in a 50L bioreactor. OUR was found to be positively correlated with the aeration rate, which reflected the oxygen supply level in each culture. The highest biomass, reaching 124.5g/L, was achieved under the highest OUR. DHA content was found to be highly correlated with the RQ value, and the highest DHA content (44.85% in total fatty acids, w/w) was achieved in the highest RQ level, which implies that the polyketide synthase pathway was more active. OUR and RQ, which reflect the physiological state of microorganisms, are suggested as synergistic real-time bioprocess monitoring parameters for DHA fermentation. PMID:27262097

  7. Production of itaconic acid in Escherichia coli expressing recombinant α-amylase using starch as substrate.

    PubMed

    Okamoto, Shusuke; Chin, Taejun; Nagata, Keisuke; Takahashi, Tetsuya; Ohara, Hitomi; Aso, Yuji

    2015-05-01

    Several studies on fermentative production of a vinyl monomer itaconic acid from hydrolyzed starch using Aspergillus terreus have been reported. Herein, we report itaconic acid production by Escherichia coli expressing recombinant α-amylase, using soluble starch as its sole carbon source. To express α-amylase in E. coli, we first constructed recombinant plasmids expressing α-amylases by using cell surface display technology derived from two amylolytic bacteria, Bacillus amyloliquefaciens NBRC 15535(T) and Streptococcus bovis NRIC 1535. The recombinant α-amylase from S. bovis (SBA) showed activity at 28°C, which is the optimal temperature for production of itaconic acid, while α-amylase from B. amyloliquefaciens displayed no noticeable activity. E. coli cells expressing SBA produced 0.15 g/L itaconic acid after 69 h cultivation under pH-stat conditions, using 1% starch as the sole carbon source. In fact, E. coli cells expressing SBA had similar growth rates when grown in the presence of 1% glucose or starch, thereby highlighting the expression of an active α-amylase that enabled utilization of starch to produce itaconic acid in E. coli. PMID:25468427

  8. Flip-flop of oleic acid in a phospholipid membrane: rate and mechanism.

    PubMed

    Wei, Chenyu; Pohorille, Andrew

    2014-11-13

    Flip-flop of protonated oleic acid molecules dissolved at two different concentrations in membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine is studied with the aid of molecular dynamics simulations at a time scale of several microseconds. Direct, single-molecule flip-flop events are observed at this time scale, and the flip-flop rate is estimated at 0.2-0.3 μs(-1). As oleic acid molecules move toward the center of the bilayer during flip-flop, they undergo gradual, correlated translational, and rotational motion. Rare, double-flipping events of two hydrogen-bonded oleic acid molecules are also observed. A two-dimensional free energy surface is obtained for the translational and rotational degree of freedom of the oleic acid molecule, and the minimum energy path on this surface is determined. A barrier to flip-flop of ~4.2 kcal/mol is found at the center of the bilayer. A two-dimensional diffusion model is found to provide a good description of the flip-flop process. The fast flip-flop rate lends support to the proposal that fatty acids permeate membranes without assistance of transport proteins. It also suggests that desorption rather than flip-flop is the rate-limiting step in fatty acid transport through membranes. The relation of flip-flop rates to the evolution of ancestral cellular systems is discussed. PMID:25319959

  9. Hydrogen Production Using Nickel Electrocatalysts with Pendant Amines: Ligand Effects on Rates and Overpotentials

    SciTech Connect

    Wiese, Stefan; Kilgore, Uriah J.; Ho, Ming-Hsun; Raugei, Simone; DuBois, Daniel L.; Bullock, R. Morris; Helm, Monte L.

    2013-11-01

    A Ni-based electrocatalyst for H2 production, [Ni(8PPh2NC6H4Br)2](BF4)2, featuring eight-membered cyclic diphosphine ligands incorporating a single amine base, 1-para-bromo-phenyl-3,7-triphenyl-1-aza-3,7-diphosphacycloheptane (8PPh2NC6H4Br) has been synthesized and characterized. X-ray diffraction studies reveal that the cation of [Ni(8PPh2NC6H4Br)2(CH3CN)](BF4)2 has a distorted trigonal bipyramidal geometry. In CH3CN [Ni(8PPh2NC6H4Br)2]2+ is an electrocatalyst for reduction of protons, and it has a maximum turnover frequency for H2 production of 800 s-1 with a 700 mV overpotential (at Ecat/2) when using [(DMF)H]OTf as the acid. Addition of H2O to acidic CH3CN solutions of [Ni(8PPh2NC6H4Br)2]2+ results in an increase of the turnover frequency for H2 production to a maximum of 3,300 s-1 with an overpotential of 760 mV at Ecat/2. Computational studies carried out on [Ni(8PPh2NC6H4Br)2]2+ indicate the observed catalytic rate is limited by formation of non-productive protonated isomers, diverting active catalyst from the catalytic cycle. The results of this research show that proton delivery from the exogenous acid to the correct position on the proton relay of the metal complex is essential for fast H2 production. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  10. Production of ascorbic acid releasing biomaterials for pelvic floor repair

    PubMed Central

    Mangır, Naşide; Bullock, Anthony J.; Roman, Sabiniano; Osman, Nadir; Chapple, Christopher; MacNeil, Sheila

    2016-01-01

    Objective An underlying abnormality in collagen turnover is implied in the occurrence of complications and recurrences after mesh augmented pelvic floor repair surgeries. Ascorbic acid is a potent stimulant of collagen synthesis. The aim of this study is to produce ascorbic acid releasing poly-lactic acid (PLA) scaffolds and evaluate them for their effects on extracellular matrix production and the strength of the materials. Materials and methods Scaffolds which contained either l-ascorbic acid (AA) and Ascorbate-2-Phosphate (A2P) were produced with emulsion electrospinning. The release of both drugs was measured by UV spectrophotometry. Human dermal fibroblasts were seeded on scaffolds and cultured for 2 weeks. Cell attachment, viability and total collagen production were evaluated as well as mechanical properties. Results No significant differences were observed between AA, A2P, Vehicle and PLA scaffolds in terms of fibre diameter and pore size. The encapsulation efficiency and successful release of both AA and A2P were demonstrated. Both AA and A2P containing scaffolds were significantly more hydrophilic and stronger in both dry and wet states compared to PLA scaffolds. Fibroblasts produced more collagen on scaffolds containing either AA or A2P compared to cells grown on control scaffolds. Conclusion This study is the first to directly compare the two ascorbic acid derivatives in a tissue engineered scaffold and shows that both AA and A2P releasing electrospun PLA scaffolds increased collagen production of fibroblasts to similar extents but AA scaffolds seemed to be more hydrophilic and stronger compared to A2P scaffolds. Statement of significance Mesh augmented surgical repair of the pelvic floor currently relies on non-degradable materials which results in severe complications in some patients. There is an unmet and urgent need for better pelvic floor repair materials. Our current understanding suggests that the ideal material should be able to better

  11. Influence of fatty acid oxidation rate on glycerol release from cardiac myocytes

    SciTech Connect

    Larsen, T.S.; Severson, D.L.

    1986-03-05

    Quiescent cardiac myocytes are characterized by low rates of fatty acid oxidation due to the reduced energy demand compared with beating hearts. The accumulation of intracellular fatty acid metabolites may, therefore, result in feed-back inhibition of the cardiac lipase responsible for the mobilization of triacylglycerols (lipolysis). The objective of this study was to examine if interventions that increase fatty acid oxidation rates in myocytes have an effect on lipolysis. Addition of 100 ..mu..M dinitrophenol (DNP) to calcium-tolerant rat ventricular myocytes caused an increase in the rate of /sup 14/C-oleic acid oxidation from 1.11 +/- 0.06 to 2.38 +/- 0.17 nmol /sup 14/CO/sub 2//10/sup 6/ cells/min (115% stimulation; mean +/- S.D., n = 3). In parallel incubations, DNP increased the rate of lipolysis from 4.4 +/- 1.7 to 13.6 +/- 3.2 nmol glycerol/10/sup 6/ cells/30 min (215% stimulation). The addition of 1 mM barium to a modified Ringer's incubation medium produced an increase in the contractile activity of the myocytes, and increased the rates of oleic acid oxidation from 0.62 +/- 0.16 to 0.88 +/- 0.23 nmol/10/sup 6/ cells/min (42% stimulation; n = 6) and lipolysis from 13.1 +/- 6.5 to 22.2 +/- 6.4 nmol/10/sup 6/ cells/30 min (70% stimulation). These data show that stimulation of fatty acid oxidation in myocardial myocytes is accompanied by increased lipolytic rates, the latter probably due to release of feed-back inhibition of cardiac lipases by accumulated fatty acid metabolites.

  12. LED light stress induced biomass and fatty acid production in microalgal biosystem, Acutodesmus obliquus

    NASA Astrophysics Data System (ADS)

    Choi, Yong-Keun; Kumaran, Rangarajulu Senthil; Jeon, Hyeon Jin; Song, Hak-Jin; Yang, Yung-Hun; Lee, Sang Hyun; Song, Kyung-Guen; Kim, Kwang Jin; Singh, Vijay; Kim, Hyung Joo

    2015-06-01

    Microbial algal system can serve as a potential source for the production of much high value bioproducts and biofuels. The quality and intensity of light are the key elements to optimize the production of algal biomass and fatty acid contents. This study presents the effect of differential LED flashing light conditions on the growth of microalgae, Acutodesmus obliquus. The induced light stress was optimized for its biomass and fatty acid content. The microalgae are exposed to various frequency of intermittent LED flashing light (blue and red lights) at three different phases in the 18 day cell growth (log, lag and stationary phase). The frequency of light flashing rate was adjusted to 120, 10, 5, 3.75, and 1 times per min. The effect of light stress on growth and fatty acids composition of A. obliquus induced an increase in algae growth and fatty acid production. Different optimal timing for light stress was subjected to elucidate the effect of light stress on algae growth and fatty acid production. The results showed an increase in the algae growth (1.2 mg/L of chl a content) under light stress condition at FT10 (flashing time, 10 times per min) from the initial day (log phase) compared with the control experiment (0.4 mg/L of chl a content). However, the total fatty acids (71 mg/g) and volumetric FAME production (9.4 ml/l) level was found to be significant under FT5 (flashing time, 5 times per min), adopting flashing light from day 10 (stationary phase). TEM studies also revealed the deposition of lipid to be largest in the 18 day old cells under flashing light (FT5) condition, representing maximum accumulation of lipids bodies (up to 770 nm diameter in particle size) occupying approximately 42% of the total area of the cell.

  13. Roles of urea production, ammonium excretion, and amino acid oxidation in acid-base balance.

    PubMed

    Mackenzie, W

    1986-02-01

    Atkinson and colleagues recently proposed several concepts that contrast with traditional views: first, that acid-base balance is regulated chiefly by the reactions leading to urea production in the liver; second, that ammonium excretion by the kidney plays no role in acid-base homeostasis; and third, that ammonium does not stimulate ureagenesis (except indirectly). To examine these concepts, plasma ions other than bicarbonate are categorized as 1) fixed cations (Na+, K+, Ca2+, and Mg2+, symbolized M+) and anions (Cl-), 2) buffer anions (A-), 3) other anions (X-), and 4) ammonium plus charged amino groups (N+). Since electroneutrality dictates that M+ + N+ = Cl- + HCO3- + A- + X-, it follows that delta HCO3- = delta(M+ - Cl-) - delta A- - delta X- + delta N+. Therefore acid-base disturbances (changes in HCO3-) can be categorized as to how they affect bodily content and hence plasma concentration of each of these four types of ions. The stoichiometry of ureagenesis, glutamine hydrolysis, ammonium and titratable acid excretion, oxidation of neutral, acidic, and basic amino acids, and oxidation of methionine, phosphoserine, and protein are examined to see how they alter these quantities. It is concluded that 1) although ureagenesis is pH dependent and also counteracts a tendency of amino acid oxidation to cause alkalosis, this tendency is inherently limited by the hyperammonemia (delta N+) that necessarily accompanies it, 2) ammonium excretion is equivalent to hydrogen excretion in its effects on acid-base balance if, and only if, it occurs in exchange for sodium or is accompanied by chloride excretion and only when the glutamate generated by glutamine hydrolysis is oxidized.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3511732

  14. Rates and mechanisms of conversion of ice nanocrystals to hydrates of HCl and HBr: acid diffusion in the ionic hydrates.

    PubMed

    Devlin, J Paul; Gulluru, Dheeraj B; Buch, Victoria

    2005-03-01

    This FTIR study focuses on solid-state chemistry associated with formation and interconversion of the ionic HX (X = Cl, Br) hydrates. Kinetic data are reported for conversions of ice nanocrystal arrays exposed to the saturation pressure of the acids in the 110 approximately 125 K range. The product is amorphous acid dihydrate in the case of HBr, and amorphous monohydrate for HCl. The rate-determining step is identified as HX diffusion through the hydrate product crust toward the interfacial reaction zone, rather than diffusion through ice, as commonly believed. Slowing of the conversion process is thus observed with increasing thickness of the crust. The diffusion coefficient (D(e)) and activation energy values for HX diffusion through the hydrates were evaluated with the help of the shrinking-core model. Hydrate crystallization occurs as a separate step, upon heating above 130 K. Subsequently, rates of reversible transitions between crystal di- and monohydrates were observed upon exposure to acid vapor and acid evacuation. In conversion from di- to monohydrate, the rate slows after fast formation of several layers; subsequently, diffusion through the product crust appears to be the rate-controlling step. The activation energy for HBr diffusion through crystal dihydrate is found to be significantly higher than that for the amorphous analogue. Conjecture is offered for a molecular mechanism of HX transport through the crystal hydrate, based on (i) spectroscopic/computational evidence for the presence of molecular HX bonded to X(-) in each of the ionic hydrate phases and (ii) the relative E(a) values found for HBr and HCl diffusion. Monte Carlo modeling suggests acid transport to the reaction zone along boundaries between "nanocrystallites" generated by multiple hydrate nucleation events at the particle surfaces. The reverse conversion, of crystalline monohydrate particles to the dihydrate phase, as well as dihydrate to trihydrate, displays nearly constant rate

  15. Microbial production of glyceric acid, an organic acid that can be mass produced from glycerol.

    PubMed

    Habe, Hiroshi; Shimada, Yuko; Yakushi, Toshiharu; Hattori, Hiromi; Ano, Yoshitaka; Fukuoka, Tokuma; Kitamoto, Dai; Itagaki, Masayuki; Watanabe, Kunihiro; Yanagishita, Hiroshi; Matsushita, Kazunobu; Sakaki, Keiji

    2009-12-01

    Glyceric acid (GA), an unfamiliar biotechnological product, is currently produced as a small by-product of dihydroxyacetone production from glycerol by Gluconobacter oxydans. We developed a method for the efficient biotechnological production of GA as a target compound for new surplus glycerol applications in the biodiesel and oleochemical industries. We investigated the ability of 162 acetic acid bacterial strains to produce GA from glycerol and found that the patterns of productivity and enantiomeric GA compositions obtained from several strains differed significantly. The growth parameters of two different strain types, Gluconobacter frateurii NBRC103465 and Acetobacter tropicalis NBRC16470, were optimized using a jar fermentor. G. frateurii accumulated 136.5 g/liter of GA with a 72% d-GA enantiomeric excess (ee) in the culture broth, whereas A. tropicalis produced 101.8 g/liter of d-GA with a 99% ee. The 136.5 g/liter of glycerate in the culture broth was concentrated to 236.5 g/liter by desalting electrodialysis during the 140-min operating time, and then, from 50 ml of the concentrated solution, 9.35 g of GA calcium salt was obtained by crystallization. Gene disruption analysis using G. oxydans IFO12528 revealed that the membrane-bound alcohol dehydrogenase (mADH)-encoding gene (adhA) is required for GA production, and purified mADH from G. oxydans IFO12528 catalyzed the oxidation of glycerol. These results strongly suggest that mADH is involved in GA production by acetic acid bacteria. We propose that GA is potentially mass producible from glycerol feedstock by a biotechnological process. PMID:19837846

  16. Microbial degradation rates of small peptides and amino acids in the oxygen minimum zone of Chilean coastal waters

    NASA Astrophysics Data System (ADS)

    Pantoja, Silvio; Rossel, Pamela; Castro, Rodrigo; Cuevas, L. Antonio; Daneri, Giovanni; Córdova, Candy

    2009-07-01

    We found similar microbial degradation rates of labile dissolved organic matter in oxic and suboxic waters off northern Chile. Rates of peptide hydrolysis and amino acid uptake in unconcentrated water samples were not low in the water column where oxygen concentration was depleted. Hydrolysis rates ranged from 65 to 160 nmol peptide L -1 h -1 in the top 20 m, 8-28 nmol peptide L -1 h -1 between 100 and 300 m (O 2-depleted zone), and 14-19 nmol peptide L -1 h -1 between 600 and 800 m. Dissolved free amino acid uptake rates were 9-26, 3-17, and 6 nmol L -1 h -1 at similar depth intervals. Since these findings are consistent with a model of comparable potential activity of microbes in degrading labile substrates of planktonic origin, we suggest, as do other authors, that differences in decomposition rates with high and low oxygen concentrations may be a matter of substrate lability. The comparison between hydrolysis and uptake rates indicates that microbial peptide hydrolysis occurs at similar or faster rates than amino acid uptake in the water column, and that the hydrolysis of peptides is not a rate-limiting step for the complete remineralization of labile macromolecules. Low O 2 waters process about 10 tons of peptide carbon per h, double the amount processed in surface-oxygenated water. In the oxygen minimum zone, we suggest that the C balance may be affected by the low lability of the dissolved organic matter when this is upwelled to the surface. An important fraction of dissolved organic matter is processed in the oxygen minimum layer, a prominent feature of the coastal ocean in the highly productive Humboldt Current System.

  17. Effects of dose, flow rate, and bile acid on diclofenac disposition in the perfused rat liver.

    PubMed

    Uraki, Misato; Kawase, Atsushi; Matsushima, Yuka; Iwaki, Masahiro

    2016-06-01

    An in situ perfused rat liver system is useful for studying the hepatic disposition of drugs and their metabolites. However, the effects of the perfusion conditions on drug disposition are unclear. We examined the effects of conditions such as flow rate (13 or 26 mL/min) and bile acid on disposition of diclofenac (DF) as a model drug and DF metabolites [diclofenac-1-O-acyl glucuronide (DF-Glu) or 4'-hydroxydiclofenac (DF-4'OH)] in the absence of albumin. DF, DF-Glu, and DF-4'OH concentrations in the perfusate and cumulative amounts of DF-Glu excreted in bile were measured using high-performance liquid chromatography methods. DF in the perfusate was rapidly eliminated as the perfusate flow rate increased. The area under the plasma concentration-time curve from 0 to 60 min (AUC0-60) for DF-Glu and DF-4'OH in a perfusate containing bile acid was lower at a flow rate of 26 and 13 mL/min, respectively. The bile flow rate at 26 mL/min with 24 μM of bile acid in the perfusate was significantly higher (ca. 3.5 times) compared with that at 13 mL/min without bile acid. Cumulative biliary DF-Glu excretion was also dramatically affected by the flow rate and addition of bile acid. This study indicated that the flow rate and bile acid in the perfused rat liver were key factors for bile flow rate and DF, DF-Glu, and DF-4'OH disposition in the absence of albumin. PMID:25656736

  18. Microbial production and applications of 5-aminolevulinic acid.

    PubMed

    Liu, Shuli; Zhang, Guangming; Li, Xiangkun; Zhang, Jie

    2014-09-01

    5-Aminolevulinic acid (ALA), an important intermediate in tetrapyrrole biosynthesis in organisms, has been widely applied in many fields, such as medicine, agriculture, and the food industry, due to its biochemical characteristics. Research efforts supporting the microbial production of ALA have received increasing interest due to its dominant advantages over chemical synthesis, including higher yields, lesser pollutant emissions, and a lesser monetary cost. ALA synthesis using photosynthetic bacteria (PSB) is a promising approach in various microbial synthesis methods. In this review, recent advances on the microbial production of ALA with an emphasis on PSB are summarized, the key enzymes in the biosynthesis pathway (especially the relationship between key enzymes and key genes) are detailed, regulation strategies are described, and the significant influencing factors on the ALA biosynthesis and application of ALA are outlined. Furthermore, the eco-friendly perspective involving the combination of wastewater treatment and microbial production of ALA is conceived. PMID:25022665

  19. Relative Reaction Rates of Sulfamic Acid and Hydroxylamine with Nitric Acid

    SciTech Connect

    Karraker, D.G.

    2001-03-28

    This report describes a study of comparative reaction rates where the reductant is in excess, as in the 1B bank in the Purex process. The results of this work apply to planned plant tests to partially substitute HAN for the ferrous sulfamate reductant in the Purex 1B bank.

  20. Vanadium phosphate catalysts for biodiesel production from acid industrial by-products.

    PubMed

    Domingues, Carina; Correia, M Joana Neiva; Carvalho, Renato; Henriques, Carlos; Bordado, João; Dias, Ana Paula Soares

    2013-04-10

    Biodiesel production from high acidity industrial by-products was studied using heterogeneous acid catalysts. These by-products contain 26-39% of free fatty acids, 45-66% of fatty acids methyl esters and 0.6-1.1% of water and are consequently inadequate for direct basic catalyzed transesterification. Macroporous vanadyl phosphate catalysts with V/P=1 (atomic ratio) prepared via sol-gel like technique was used as catalyst and it was possible to produce in one reaction batch a biodiesel contain 87% and 94% of FAME, depending on the by-product used as raw material. The initial FAME content in the by-products had a beneficial effect on the reactions because they act as a co-solvent, thus improving the miscibility of the reaction mixture components. The water formed during esterification process seems to hinder the esters formation, possibly due to competitive adsorption with methanol and to the promotion of the FAME hydrolysis reaction.The observed catalyst deactivation seems to be related to the reduction of vanadium species. However, spent catalysts can be regenerated, even partially, by reoxidation of the reduced vanadium species with air. PMID:22902409

  1. Biological production of acetic acid from waste gases with Clostridium ljungdahlii

    DOEpatents

    Gaddy, James L.

    1998-01-01

    A method and apparatus for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration.

  2. Biological production of acetic acid from waste gases with Clostridium ljungdahlii

    DOEpatents

    Gaddy, J.L.

    1998-09-15

    A method and apparatus are disclosed for converting waste gases from industrial processes such as oil refining, carbon black, coke, ammonia, and methanol production, into useful products. The method includes introducing the waste gases into a bioreactor where they are fermented to various organic acids or alcohols by anaerobic bacteria within the bioreactor. These valuable end products are then recovered, separated and purified. In an exemplary recovery process, the bioreactor raffinate is passed through an extraction chamber into which one or more non-inhibitory solvents are simultaneously introduced to extract the product. Then, the product is separated from the solvent by distillation. Gas conversion rates can be maximized by use of centrifuges, hollow fiber membranes, or other means of ultrafiltration to return entrained anaerobic bacteria from the bioreactor raffinate to the bioreactor itself, thus insuring the highest possible cell concentration. 5 figs.

  3. Introduction of a bacterial acetyl-CoA synthesis pathway improves lactic acid production in Saccharomyces cerevisiae.

    PubMed

    Song, Ji-Yoon; Park, Joon-Song; Kang, Chang Duk; Cho, Hwa-Young; Yang, Dongsik; Lee, Seunghyun; Cho, Kwang Myung

    2016-05-01

    Acid-tolerant Saccharomyces cerevisiae was engineered to produce lactic acid by expressing heterologous lactate dehydrogenase (LDH) genes, while attenuating several key pathway genes, including glycerol-3-phosphate dehydrogenase1 (GPD1) and cytochrome-c oxidoreductase2 (CYB2). In order to increase the yield of lactic acid further, the ethanol production pathway was attenuated by disrupting the pyruvate decarboxylase1 (PDC1) and alcohol dehydrogenase1 (ADH1) genes. Despite an increase in lactic acid yield, severe reduction of the growth rate and glucose consumption rate owing to the absence of ADH1 caused a considerable decrease in the overall productivity. In Δadh1 cells, the levels of acetyl-CoA, a key precursor for biologically applicable components, could be insufficient for normal cell growth. To increase the cellular supply of acetyl-CoA, we introduced bacterial acetylating acetaldehyde dehydrogenase (A-ALD) enzyme (EC 1.2.1.10) genes into the lactic acid-producing S. cerevisiae. Escherichia coli-derived A-ALD genes, mhpF and eutE, were expressed and effectively complemented the attenuated acetaldehyde dehydrogenase (ALD)/acetyl-CoA synthetase (ACS) pathway in the yeast. The engineered strain, possessing a heterologous acetyl-CoA synthetic pathway, showed an increased glucose consumption rate and higher productivity of lactic acid fermentation. The production of lactic acid was reached at 142g/L with production yield of 0.89g/g and productivity of 3.55gL(-1)h(-1) under fed-batch fermentation in bioreactor. This study demonstrates a novel approach that improves productivity of lactic acid by metabolic engineering of the acetyl-CoA biosynthetic pathway in yeast. PMID:26384570

  4. The use of date waste for lactic acid production by a fed-batch culture using Lactobacillus casei subsp. rhamnosus

    PubMed Central

    Nancib, Aicha; Nancib, Nabil; Boubendir, Abdelhafid; Boudrant, Joseph

    2015-01-01

    The production of lactic acid from date juice by Lactobacillus caseisubsp. rhamnosus in batch and fed-batch cultures has been investigated. The fed-batch culture system gave better results for lactic acid production and volumetric productivity. The aim of this work is to determine the effects of the feeding rate and the concentration of the feeding medium containing date juice glucose on the cell growth, the consumption of glucose and the lactic acid production by Lactobacillus casei subsp. rhamnosus in fed-batch cultures. For this study, two concentrations of the feeding medium (62 and 100 g/L of date juice glucose) were tested at different feeding rates (18, 22, 33, 75 and 150 mL/h). The highest volumetric productivity (1.3 g/L.h) and lactic acid yield (1.7 g/g) were obtained at a feeding rate of 33 mL/h and a date juice glucose concentration of 62 g/L in the feeding medium. As a result, most of the date juice glucose was completely utilised (residual glucose 1 g/L), and a maximum lactic acid production level (89.2 g/L) was obtained. PMID:26413076

  5. Analysis of acidity production during enhanced reductive dechlorination using a simplified reactive transport model

    NASA Astrophysics Data System (ADS)

    Brovelli, A.; Barry, D. A.; Robinson, C.; Gerhard, J. I.

    2012-07-01

    Build-up of fermentation products and hydrochloric acid at a contaminated site undergoing enhanced reductive dechlorination can result in groundwater acidification. Sub-optimal pH conditions can inhibit microbial activity and lead to reduced dechlorination rates. The extent of acidification likely to occur is site-specific and depends primarily on the extent of fermentation and dechlorination, the geochemical composition of soil and groundwater, and the pH-sensitivity of the active microbial populations. Here, the key chemical and physical mechanisms that control the extent of groundwater acidification in a contaminated site were examined, and the extent to which the remediation efficiency was affected by variations in groundwater pH was evaluated using a simplified process-based reactive-transport model. This model was applied successfully to a well-documented field site and was then employed in a sensitivity analysis to identify the processes likely to significantly influence acidity production and subsequent microbial inhibition. The accumulation of organic acids produced from the fermentation of the injected substrate was the main cause of the pH change. The concentration of dissolved sulphates controlled substrate utilisation efficiency because sulphate-reducing biomass competed with halo-respiring biomass for the fermentation products. It was shown further that increased groundwater velocity increases dilution and reduces the accumulation of acidic products. As a consequence, the flow rate corresponding to the highest remediation efficiency depends on the fermentation and dechlorination rates. The model enables investigation and forecasting of the extent and areal distribution of pH change, providing a means to optimise the application of reductive dechlorination for site remediation.

  6. Analysis of mycolic acid cleavage products and cellular fatty acids of Mycobacterium species by capillary gas chromatography.

    PubMed

    Lambert, M A; Moss, C W; Silcox, V A; Good, R C

    1986-04-01

    After growth and experimental conditions were established, the mycolic acid cleavage products, constituent fatty acids, and alcohols of representative strains of Mycobacterium tuberculosis, M. smegmatis, M. fortuitum complex, M. kansasii, M. gordonae, and M. avium complex were determined by capillary gas chromatography. Reproducible cleavage of mycolic acid methyl esters to tetracosanoic (24:0) or hexacosanoic (26:0) acid methyl esters was achieved by heating the sample in a high-temperature muffle furnace. The major constituent fatty acids in all species were hexadecanoic (16:0) and octadecenoic (18:1 omega 9-c, oleic) acids. With the exception of M. gordonae, 10-methyloctadecanoic acid was found in all species; moreover, M. gordonae was the only species tested which contained 2-methyltetradecanoic acid. M. kansasii was characterized by the presence of 2,4-dimethyltetradecanoic acid, M. avium complex by 2-eicosanol, and M. tuberculosis by 26:0 mycolic acid cleavage product. The mycolic acid cleavage product in the other five species tested was 24:0. Although a limited number of strains and species were tested, preliminary results indicate that this gas chromatographic method can be used to characterize mycobacterial cultures by their mycolic acid cleavage products and constituent fatty acid and alcohol content. PMID:3084554

  7. The effect of oxalic and itaconic acids on threo-Ds-isocitric acid production from rapeseed oil by Yarrowia lipolytica.

    PubMed

    Kamzolova, Svetlana V; Allayarov, Ramil K; Lunina, Julia N; Morgunov, Igor G

    2016-04-01

    The effect of oxalic and itaconic acids, the inhibitors of the isocitrate lyase, on the production of isocitric acid by the wild strain Yarrowia lipolytica VKM Y-2373 grown in the medium containing rapeseed oil was studied. In the presence of oxalic and itaconic acids, strain Y. lipolytica accumulated in the medium isocitric acid (70.0 and 82.7 g/L, respectively) and citric acid (23.0 and 18.4 g/L, respectively). In control experiment, when the inhibitors were not added to the medium, the strain accumulated isocitric and citric acids at concentrations of 62.0 and 28.0 g/L, respectively. Thus, the use of the oxalic and itaconic acids as additives to the medium is a simple and convenient method of isocitric acid production with a minimum content of citric acid. PMID:26851896

  8. 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

  9. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  10. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  11. Microbial production of fatty acid-derived fuels and chemicals

    PubMed Central

    Lennen, Rebecca M; Pfleger, Brian F

    2013-01-01

    Fatty acid metabolism is an attractive route to produce liquid transportation fuels and commodity oleochemicals from renewable feedstocks. Recently, genes and enzymes, which comprise metabolic pathways for producing fatty acid-derived compounds (e.g. esters, alkanes, olefins, ketones, alcohols, polyesters) have been elucidated and used in engineered microbial hosts. The resulting strains often generate products at low percentages of maximum theoretical yields, leaving significant room for metabolic engineering. Economically viable processes will require strains to approach theoretical yields, particularly for replacement of petroleum-derived fuels. This review will describe recent progress toward this goal, highlighting the scientific discoveries of each pathway, ongoing biochemical studies to understand each enzyme, and metabolic engineering strategies that are being used to improve strain performance. PMID:23541503

  12. Valeric acid induces cell cycle arrest at G1 phase in CHO cell cultures and improves recombinant antibody productivity.

    PubMed

    Park, Jin Hyoung; Noh, Soo Min; Woo, Ju Rang; Kim, Jong Won; Lee, Gyun Min

    2016-03-01

    To find a more effective chemical reagent for improved monoclonal antibody (mAb) production, eight chemical reagents (curcumin, quercein, DL-sulforaphane, thymidine, valeric acid, phenyl butyrate, valproic acid, and lithium chloride) known to induce cell cycle arrest were examined individually as chemical additives to recombinant CHO (rCHO) cell cultures producing mAb. Among these chemical additives, valeric acid showed the best production performance. Valeric acid decreased specific growth rate (μ), but increased culture longevity and specific mAb productivity (qmAb ) in a dose-dependent manner. The beneficial effect of valeric acid on culture longevity and qmAb outweighed its detrimental effect on μ, resulting in 2.9-fold increase in the maximum mAb concentration when 1.5 mM valeric acid was added to the cultures. Furthermore, valeric acid did not negatively affect the mAb quality attributes with regard to aggregation, charge variation, and galactosylation. Unexpectedly, galactosylation of the mAb increased by the 1.5 mM valeric acid addition. Taken together, the results obtained here demonstrate that valeric acid is an effective chemical reagent to increase mAb production in rCHO cells. PMID:26663903

  13. [Expression of Mortierella isabellina delta6-fatty acid desaturase gene in gamma-linolenic acid production in transgenic tobacco].

    PubMed

    Li, Ming-Chun; Liu, Li; Hu, Guo-Wu; Xing, Lai-Jun

    2003-03-01

    Gamma-linolenic acid (GLA, C18:3delta6.9.12) is nutritional and important polyunsaturated fatty acid in human and animal diets. GLA play an important role in hormone regulation and fatty acid metabolization. Furthermore it is also the biological precursor of a group of molecules, including prostaglandins, leukotrienes and thromboxanes. Vast majority of oilseed crops do not produce GLA, but linoleic acid (LA, C18:2delta9.12) as its substrate. GLA is only produced by a small number of oilseed plants such as evening promrose ( Oenotheera spp.), borage (Borago officinalis) and etc. delta6-fatty acid desaturase (D6D) is the rate-limiting enzyme in the production of GLA. It can convert from linoleic acid to linolenic acid. To produce GLA in tobacco, plant expression vector was first constructed. To facilitate preparation of plant expression constructs, flanking Xba I and Bgl II restriction enzyme sites were added to the coding region of clone pTMICL6 by PCR amplification. pTMICL6 contains delta6-fatty acid desaturase gene cloned from Mortierella isabellina which is an oil-producing fugus. The PCR product was purified and subcloned into the plant expression vector pGA643 to generate the recombinant vector pGAMICL6 which contains the ORF of the D6D gene of Mortierella isabellina, together with regulatory elements consisting of the cauliflower mosaic virus 35S promoter and the nopaline synthase (nos) termination sequence. The plasmid pGAMICL6 was transformed into Agrobacterium tumefaciens strain LBA4404 by method of freeze thawing of liquid nitrogen. Transformants were selected by plating on YEB medium plates containing kanamycin and streptomycin and grown overnight at 28 degrees C, then transformants were further identified by PCR. The positive transformant containing the plant expression vector pGAMICL6 was transformed into tobacco ( Nicotiana tabacum cv. Xanthi) via Agrobacterium infection. Transgenic plants were selected on 100 microg/mL kanamycin. Plants were

  14. Ethanesulfonic acid-based esterification of industrial acidic crude palm oil for biodiesel production.

    PubMed

    Hayyan, Adeeb; Mjalli, Farouq S; Hashim, Mohd Ali; Hayyan, Maan; AlNashef, Inas M; Al-Zahrani, Saeed M; Al-Saadi, Mohammed A

    2011-10-01

    An industrial grade acidic crude palm oil (ACPO) pre-treatment process was carried out using ethanesulfonic acid (ESA) as a catalyst in the esterification reaction. ESA was used in different dosages to reduce free fatty acid (FFA) to a minimum level for the second stage of biodiesel production via alkaline transesterification reaction. Different process operating conditions were optimized such as ESA dosage (0.25-3.5% wt/wt), methanol to ACPO molar ratio (1:1-20:1), reaction temperature (40-70 °C), and reaction time (3-150 min). This study revealed the potential use of abundant quantities of ACPO from oil palm mills for biodiesel production. The lab scale results showed the effectiveness of the pre-treatment process using ESA catalyst. Three consecutive catalyst recycling runs were achieved without significant degradation in its performance. Second and third reuse runs needed more reaction time to achieve the target level of FFA content. Esterification and transesterification using ESA and KOH respectively is proposed for biodiesel industrial scale production. The produced biodiesel meets the international standards specifications for biodiesel fuel (EN 14214 and ASTM D6751). PMID:21855329

  15. The Use of Lactic Acid Bacteria Starter Culture in the Production of Nunu, a Spontaneously Fermented Milk Product in Ghana.

    PubMed

    Akabanda, Fortune; Owusu-Kwarteng, James; Tano-Debrah, Kwaku; Parkouda, Charles; Jespersen, Lene

    2014-01-01

    Nunu, a spontaneously fermented yoghurt-like product, is produced and consumed in parts of West Africa. A total of 373 predominant lactic acid bacteria (LAB) previously isolated and identified from Nunu product were assessed in vitro for their technological properties (acidification, exopolysaccharides production, lipolysis, proteolysis and antimicrobial activities). Following the determination of technological properties, Lactobacillus fermentum 22-16, Lactobacillus plantarum 8-2, Lactobacillus helveticus 22-7, and Leuconostoc mesenteroides 14-11 were used as single and combined starter cultures for Nunu fermentation. Starter culture fermented Nunu samples were assessed for amino acids profile and rate of acidification and were subsequently evaluated for consumer acceptability. For acidification properties, 82%, 59%, 34%, and 20% of strains belonging to Lactobacillus helveticus, L. plantarum, L. fermentum, and Leu. mesenteriodes, respectively, demonstrated fast acidification properties. High proteolytic activity (>100 to 150 μg/mL) was observed for 50% Leu. mesenteroides, 40% L. fermentum, 41% L. helveticus, 27% L. plantarum, and 10% Ent. faecium species. In starter culture fermented Nunu samples, all amino acids determined were detected in Nunu fermented with single starters of L. plantarum and L. helveticus and combined starter of L. fermntum and L. helveticus. Consumer sensory analysis showed varying degrees of acceptability for Nunu fermented with the different starter cultures. PMID:26904646

  16. The Use of Lactic Acid Bacteria Starter Culture in the Production of Nunu, a Spontaneously Fermented Milk Product in Ghana

    PubMed Central

    Tano-Debrah, Kwaku; Parkouda, Charles; Jespersen, Lene

    2014-01-01

    Nunu, a spontaneously fermented yoghurt-like product, is produced and consumed in parts of West Africa. A total of 373 predominant lactic acid bacteria (LAB) previously isolated and identified from Nunu product were assessed in vitro for their technological properties (acidification, exopolysaccharides production, lipolysis, proteolysis and antimicrobial activities). Following the determination of technological properties, Lactobacillus fermentum 22-16, Lactobacillus plantarum 8-2, Lactobacillus helveticus 22-7, and Leuconostoc mesenteroides 14-11 were used as single and combined starter cultures for Nunu fermentation. Starter culture fermented Nunu samples were assessed for amino acids profile and rate of acidification and were subsequently evaluated for consumer acceptability. For acidification properties, 82%, 59%, 34%, and 20% of strains belonging to Lactobacillus helveticus, L. plantarum, L. fermentum, and Leu. mesenteriodes, respectively, demonstrated fast acidification properties. High proteolytic activity (>100 to 150 μg/mL) was observed for 50% Leu. mesenteroides, 40% L. fermentum, 41% L. helveticus, 27% L. plantarum, and 10% Ent. faecium species. In starter culture fermented Nunu samples, all amino acids determined were detected in Nunu fermented with single starters of L. plantarum and L. helveticus and combined starter of L. fermntum and L. helveticus. Consumer sensory analysis showed varying degrees of acceptability for Nunu fermented with the different starter cultures. PMID:26904646

  17. Production of orotic acid by a Klura3Δ mutant of Kluyveromyces lactis.

    PubMed

    Carvalho, Nuno; Coelho, Eduardo; Gales, Luís; Costa, Vítor; Teixeira, José António; Moradas-Ferreira, Pedro

    2016-06-01

    We demonstrated that a Klura3Δ, mutant of the yeast Kluyveromyces lactis is able to produce and secrete into the growth medium considerable amounts of orotic acid. Using yeast extract-peptone-glucose (YPD) based media we optimized production conditions in flask and bioreactor cultures. With cells grown in YPD 5% glucose medium, the best production in flask was obtained with a 1:12.5 ratio for flask: culture volume, 180 rpm, 28°C and 200 mM MOPS for pH stabilization at neutral values (initial culture pH at 8.0). The best production in a 2 L bioreactor was achieved at 500 rpm with 1 vvm aeration, 28°C and pH 7.0. Under these optimum conditions, similar rates of orotic acid production were obtained and maximum concentration achieved after 96 h was 6.7 g/L in flask and bioreactor cultures. These results revealed an excellent reproducibility between both systems and provided evidence for the biotechnological potential of Klura3Δ strain to produce orotic acid since the amounts obtained are comparable to the production in flask using a similar mutant of the industrially valuable Corynebacterium glutamicum. PMID:26707627

  18. Potential role of stabilized Criegee radicals in sulfuric acid production in a high biogenic VOC environment.

    PubMed

    Kim, Saewung; Guenther, Alex; Lefer, Barry; Flynn, James; Griffin, Robert; Rutter, Andrew P; Gong, Longwen; Cevik, Basak Karakurt

    2015-03-17

    We present field observations made in June 2011 downwind of Dallas-Fort Worth, TX, and evaluate the role of stabilized Criegee radicals (sCIs) in gaseous sulfuric acid (H2SO4) production. Zero-dimensional model calculations show that sCI from biogenic volatile organic compounds composed the majority of the sCIs. The main uncertainty associated with an evaluation of H2SO4 production from the sCI reaction channel is the lack of experimentally determined reaction rates for sCIs formed from isoprene ozonolysis with SO2 along with systematic discrepancies in experimentally derived reaction rates between other sCIs and SO2 and water vapor. In general, the maximum of H2SO4 production from the sCI channel is found in the late afternoon as ozone increases toward the late afternoon. The sCI channel, however, contributes minor H2SO4 production compared with the conventional OH channel in the mid-day. Finally, the production and the loss rates of H2SO4 are compared. The application of the recommended mass accommodation coefficient causes significant overestimation of H2SO4 loss rates compared with H2SO4 production rates. However, the application of a lower experimental value for the mass accommodation coefficient provides good agreement between the loss and production rates of H2SO4. The results suggest that the recommended coefficient for the H2O surface may not be suitable for this relatively dry environment. PMID:25700170

  19. Kinetics of D-lactic acid production by Sporolactobacillus sp. strain CASD using repeated batch fermentation.

    PubMed

    Zhao, Bo; Wang, Limin; Li, Fengsong; Hua, Dongliang; Ma, Cuiqing; Ma, Yanhe; Xu, Ping

    2010-08-01

    D-lactic acid was produced by Sporolactobacillus sp. strain CASD in repeated batch fermentation with one- and two-reactor systems. The strain showed relatively high energy consumption in its growth-related metabolism in comparison with other lactic acid producers. When the fermentation was repeated with 10% (v/v) of previous culture to start a new batch, D-lactic acid production shifted from being cell-maintenance-dependent to cell-growth-dependent. In comparison with the one-reactor system, D-lactic acid production increased approximately 9% in the fourth batch of the two-reactor system. Strain CASD is an efficient D-lactic acid producer with increased growth rate at the early stage of repeated cycles, which explains the strain's physiological adaptation to repeated batch culture and improved performance in the two-reactor fermentation system. From a kinetic point of view, two-reactor fermentation system was shown to be an alternative for conventional one-reactor repeated batch operation. PMID:20374976

  20. Photo-Fenton-like treatment of K-acid: assessment of treatability, toxicity and oxidation products.

    PubMed

    Olmez-Hanci, Tugba; Arslan-Alaton, Idil; Gelegen, Ozlem

    2014-01-01

    Photo-Fenton-like treatment of the commercially important naphthalene sulphonate K-acid (2-naphthylamine-3,6,8-trisulphonic acid) was investigated using UV-C, UV-A and visible light irradiation. Changes in toxicity patterns were followed by the Vibrio fischeri bioassay. Rapid and complete degradation of K-acid accompanied with nearly complete oxidation and mineralization rates (>90%) were achieved for all studied irradiation types. On the other hand, detoxification was rather limited and did not change significantly during photo-Fenton-like treatment. Several oxidation products could be identified via liquid chromatograph-mass spectrometer analyses, such as desulphonated and hydroxylated naphthalene derivatives, quinones, and ring-opening as well as dimerization products. Photo-Fenton-like treatment of K-acid with UV-C, UV-A and visible light irradiation occurred through a series of hydroxylation and desulphonation reactions, followed by ring cleavage. A common degradation pathway for photo-Fenton-like treatment of K-acid using different irradiation types was proposed. PMID:25259495

  1. Production of chlorogenic acid and its derivatives in hairy root cultures of Stevia rebaudiana.

    PubMed

    Fu, Xiao; Yin, Zhong-Ping; Chen, Ji-Guang; Shangguan, Xin-Chen; Wang, Xiaoqiang; Zhang, Qing-Feng; Peng, Da-Yong

    2015-01-14

    Chlorogenic acid and its derivatives (CADs) are valuable bioactive plant secondary metabolites with many health benefits. In the present study, Stevia rebaudiana hairy root cultures were established, and the culture conditions for the production of CADs were optimized. The hairy roots were induced by coculture of S. rebaudiana leaves and Agrobacterium rhizogenes (C58C1) after infection, which were further verified by PCR detection of rolB and rolC genes. HPLC-MS and HPLC analysis showed that chlorogenic acid (3-caffeoylquinic acid, 3-CQA), 3,5-dicaffeoylquinic acid (3,5-CQA), and 4,5-dicaffeoylquinic acid (4,5-CQA) were the major CADs in the hairy roots. Eight single roots with rapid growth rate were selected. Among them, T3 had the highest yield of CADs. B5 medium supplemented with 40 g/L sucrose was more suitable for the production of CADs than others. Under optimal culture conditions, the total content of these three compounds reached 105.58 mg/g and total yield was 234.40 mg/100 mL. PMID:25548875

  2. Efficient production of triacylglycerols rich in docosahexaenoic acid (DHA) by osmo-heterotrophic marine protists.

    PubMed

    Liu, Ying; Tang, Jie; Li, Jingjing; Daroch, Maurycy; Cheng, Jay J

    2014-12-01

    Thraustochytrids have recently emerged as a promising source for docosahexaenoic acid (DHA) production due to their high growth rate and oil content. In this study, two thraustochytrid isolates, Aurantiochytrium sp. PKU#SW7 and Thraustochytriidae sp. PKU#Mn16 were used for DHA production. Following growth parameters were optimized to maximize DHA production: temperature, pH, salinity, and glucose concentration. Both isolates achieved the highest DHA yield at the cultivation temperature of 28 °C, pH 6, 100 % seawater, and 2 % glucose. A DHA yield of 1.395 g/l and 1.426 g/l was achieved under the optimized culture conditions. Further investigation revealed that both isolates possess simple fatty acids profiles with palmitic acid and DHA as their dominant constituents, accounting for ∼79 % of total fatty acids. To date, very few studies have focused on the DHA distribution in various lipid fractions which is an important factor for identifying strains with a potential for industrial DHA production. In the present study, the lipids profiles of each strain both revealed that the majority of DHA was distributed in neutral lipids (NLs), and the DHA distribution in NLs of PKU#SW7 was exclusively in the form of triacylglycerols (TAGs) which suggest that PKU#SW7 could be utilized as an alternative source of DHA for dietary supplements. The fermentation process established for both strains also indicating that Aurantiochytrium sp. PKU#SW7 was more suitable for cultivation in fermenter. In addition, the high percentage of saturated fatty acids produced by the two thraustochytrids indicates their potential application in biodiesel production. Overall, our findings suggest that two thraustochytrid isolates are suitable candidates for biotechnological applications. PMID:25186147

  3. Production and physicochemical assessment of new stevia amino acid sweeteners from the natural stevioside.

    PubMed

    Khattab, Sherine N; Massoud, Mona I; Jad, Yahya El-Sayed; Bekhit, Adnan A; El-Faham, Ayman

    2015-04-15

    New stevia amino acid sweeteners, stevia glycine ethyl ester (ST-GL) and stevia l-alanine methyl ester (ST-GL), were synthesised and characterised by IR, NMR ((1)H NMR and (13)C NMR) and elemental analysis. The purity of the new sweeteners was determined by HPLC and their sensory properties were evaluated relative to sucrose in an aqueous system. Furthermore, the stevia derivatives (ST-GL and ST-AL) were evaluated for their acute toxicity, melting point, solubility and heat stability. The novel sweeteners were stable in acidic, neutral or basic aqueous solutions maintained at 100 °C for 2 h. The sweetness intensity rate of the novel sweeteners was higher than sucrose. Stevia amino acid (ST-GL and ST-AL) solutions had a clean sweetness taste without bitterness when compared to stevioside. The novel sweeteners can be utilised as non-caloric sweeteners in the production of low-calorie food. PMID:25466115

  4. 40 CFR 721.10629 - Fatty acids, tall-oil, reaction products with modified fatty acids and polyalkanolamines (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Fatty acids, tall-oil, reaction... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10629 Fatty acids, tall-oil, reaction products with modified fatty acids and polyalkanolamines (generic)....

  5. 40 CFR 721.10629 - Fatty acids, tall-oil, reaction products with modified fatty acids and polyalkanolamines (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Fatty acids, tall-oil, reaction... NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10629 Fatty acids, tall-oil, reaction products with modified fatty acids and polyalkanolamines (generic)....

  6. 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

  7. Process for chemical reaction of amino acids and amides yielding selective conversion products

    DOEpatents

    Holladay, Jonathan E.

    2006-05-23

    The invention relates to processes for converting amino acids and amides to desirable conversion products including pyrrolidines, pyrrolidinones, and other N-substituted products. L-glutamic acid and L-pyroglutamic acid provide general reaction pathways to numerous and valuable selective conversion products with varied potential industrial uses.

  8. 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

  9. Metabolic modeling of fumaric acid production by Rhizopus arrhizus

    SciTech Connect

    Gangl, I.C.; Weigand, W.W.; Keller, F.A.

    1991-12-31

    A metabolic model is developed for fumaric acid production by Rhizopus arrhizus. The model describes the reaction network and the extents of reaction in terms of the concentrations of the measurable species. The proposed pathway consists of the Embden-Meyerhof pathway and two pathways to FA production, both of which require CO{sub 2} fixation (the forward and the reverse TCA cycles). Relationships among the measurable quantities, in addition to those obtainable by a macroscopic mass balance, are found by invoking a pseudo-steady-state assumption on the nonaccumulating species in the pathway. Applications of the metabolic model, such as verifying the proposed pathway, obtaining the theoretical yield and selectivity, and detecting experimental errors, are discussed.

  10. Aspergillus oryzae nrtA affects kojic acid production.

    PubMed

    Sano, Motoaki

    2016-09-01

    We analyzed the role of the nitrate transporter-encoding gene (nrtA) of Aspergillus oryzae by gene disruption. Southern hybridization analysis indicated that homologous recombination occurred at the resident nrtA locus. Real-time PCR showed that the nrtA gene was strongly inducible by NaNO3. The nrtA disruptant did not exhibit normal growth when nitrate was available as the sole nitrogen source. These results indicate that NrtA is essential for nitrate uptake in A. oryzae. Kojic acid (KA) production was inhibited by the addition of a small amount of sodium nitrate. The nrtA-disrupted strain was deficient in the uptake of nitrate. As a result, KA production in this strain was not considerably affected by the presence of nitrate. PMID:27108780

  11. Production of Poly (3-Hydroxybutyric Acid) by Ralstonia eutropha in a Biocalorimeter and its Thermokinetic Studies.

    PubMed

    Anusha, Subramanian Mohanakrishnan; Leelaram, Santharam; Surianarayanan, Mahadevan

    2016-07-01

    Bioplastic production from microbial sources is an emerging area which provides opportunities even to convert the wastes into bioplastics. Poly (3-hydroxybutyric acid), commonly called as PHB, is a bioplastic, which is stored as intracellular cytoplasmic inclusions in microorganisms. The objectives of this study are to calorimetrically monitor the PHB production and evaluate the thermokinetic data in a bioreaction calorimeter (BioRC1e). Thus, a well-known PHB-producing bacteria Ralstonia eutropha was selected for batch process in a bioreaction calorimeter. The metabolic heat generated was found to be correlated with the biomass, substrate consumption, oxygen uptake rate (OUR), carbon dioxide evolution rate (CER) and PHB production. The OUR pattern explained the oxidative metabolism of the strain R. eutropha. The heat yields due to biomass and glucose consumption during PHB production were found to be 12.56 and 13.56 kJ/g, respectively. The oxycalorific value obtained for the PHB production was 443.80 kJ/mol of O2. The concentration of PHB obtained in BioRC1e was 4.33 g/L with a production rate of 0.09 g/L/h. The chemical structure of the extracted PHB by R. eutropha was confirmed using fourier transform infrared spectroscopy (FT-IR) and (1)H and (13)C nuclear magnetic resonance (NMR) analysis. PMID:27003281

  12. Hydrogen production by photoelectrochemically splitting solutions of formic acid.

    PubMed

    Li, Lei; Guo, Wenliang; Zhu, Yusong; Wu, Yuping

    2011-10-17

    A TiO₂/FTO (FTO=fluorine-doped tin oxide) electrode was prepared by dip-coating FTO in a suspension of TiO₂ prepared from a sol-gel method and was used as a photoanode to split an aqueous solution of formic acid to produce hydrogen. The surface of the TiO₂/FTO film was covered with assemblies of TiO₂ nanoparticles with a diameter of approximately 20 nm. Under irradiation by using a Xe lamp, splitting of formic acid was performed at different applied current densities. Compared to splitting water or utilizing FTO and Pt foil as the anode, the splitting voltage is much lower and can be as low as -0.27 V. The results show that the splitting voltage is related to the concentration of free formate groups. The evolution rate of hydrogen measured by using gas chromatography is 130 μmol h⁻¹ at a current density of 20 mA cm⁻² and the energy-conversion efficiency can be 1.79 %. Photoelectrolysis of formic acid has the potential to be an efficient way to produce hydrogen with a high energy-conversion efficiency. PMID:21994155

  13. Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting.

    PubMed

    Kosugi, Akihiko; Tanaka, Ryohei; Magara, Kengo; Murata, Yoshinori; Arai, Takamitsu; Sulaiman, Othman; Hashim, Rokiah; Hamid, Zubaidah Aimi Abdul; Yahya, Mohd Khairul Azri; Yusof, Mohd Nor Mohd; Ibrahim, Wan Asma; Mori, Yutaka

    2010-09-01

    Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia. PMID:20547348

  14. Relationship between morphology and itaconic acid production by Aspergillus terreus.

    PubMed

    Gao, Qian; Liu, Jie; Liu, Liming

    2014-02-28

    The morphology of filamentous fungi closely correlates with the productivity in submerged culture. Using itaconic acid (IA) production by Aspergillus terreus as a research model, the quantitative relationship between the growth form of A. terreus and IA production was investigated. IA fermentation was scaled up from shake flasks to a 7 L stirred tank bioreactor based on the quantitative relationship. Our results demonstrated the following: (1) Three morphologies of A. terreus were formed by changing the inoculum level and shape of the flask. (2) Investigation of the effects of the three morphologies on broth rheology and IA production revealed the higher yield of IA on dry cell weight (DCW, IA/DCW) and yield of glucose on DCW (consumed glucose/DCW) were achieved during clump growth of A. terreus. (3) By varying the KH2PO4 concentration and culture temperature, the relationships between clump diameter and IA production were established, demonstrating that the yield of IA on DCW (R(2) = 0.9809) and yield of glucose on DCW (R(2) = 0.9421) were closely correlated with clump diameter. The optimum clump diameter range for higher IA production was 0.40-0.50 mm. (4) When the clump diameter was controlled at 0.45 mm by manipulating the mechanical stress in a 7 L fermentor, the yield of IA on DCW and yield of glucose on DCW were increased by 25.1% and 16.3%, respectively. The results presented in this study provide a potential approach for further enhancement of metabolite production by filamentous fungi. PMID:24169454

  15. Lactic acid production from acidogenic fermentation of fruit and vegetable wastes.

    PubMed

    Wu, Yuanyuan; Ma, Hailing; Zheng, Mingyue; Wang, Kaijun

    2015-09-01

    This work focused on the lactic acid production from acidogenic fermentation of fruit and vegetable wastes treatment. A long term completely stirred tank reactor (CSTR) lasting for 50 days was operated at organic loading rate (OLR) of 11 gVS/(L d) and sludge retention time (SRT) of 3 days with pH controlled at 4.0 (1-24 day) and 5.0 (25-50 day). The results indicated that high amount of approximately 10-20 g/L lactic acid was produced at pH of 4.0 and the fermentation type converted from coexistence of homofermentation and heterofermentation into heterofermentation. At pH of 5.0, the hydrolysis reaction was improved and the total concentration of fermentation products increased up to 29.5 g COD/L. The heterofermentation was maintained, however, bifidus pathway by Bifidobacterium played an important role. PMID:25983222

  16. Effects of alpha-amylase and its inhibitors on acid production from cooked starch by oral streptococci.

    PubMed

    Aizawa, S; Miyasawa-Hori, H; Nakajo, K; Washio, J; Mayanagi, H; Fukumoto, S; Takahashi, N

    2009-01-01

    This study evaluated acid production from cooked starch by Streptococcus mutans, Streptococcus sobrinus, Streptococcus sanguinis and Streptococcus mitis, and the effects of alpha-amylase inhibitors (maltotriitol and acarbose) and xylitol on acid production. Streptococcal cell suspensions were anaerobically incubated with various carbohydrates that included cooked potato starch in the presence or absence of alpha-amylase. Subsequently, the fall in pH and the acid production rate at pH 7.0 were measured. In addition, the effects of adding alpha-amylase inhibitors and xylitol to the reaction mixture were evaluated. In the absence of alpha-amylase, both the fall in pH and the acid production rate from cooked starch were small. On the other hand, in the presence of alpha-amylase, the pH fell to 3.9-4.4 and the acid production rate was 0.61-0.92 micromol per optical density unit per min. These values were comparable to those for maltose. When using cooked starch, the fall in pH by S. sanguinis and S. mitis was similar to that by S. mutans and S. sobrinus. For all streptococci, alpha-amylase inhibitors caused a decrease in acid production from cooked starch, although xylitol only decreased acid production by S. mutans and S. sobrinus. These results suggest that cooked starch is potentially acidogenic in the presence of alpha-amylase, which occurs in the oral cavity. In terms of the acidogenic potential of cooked starch, S. sanguinis and S. mitis were comparable to S. mutans and S. sobrinus. Alpha-amylase inhibitors and xylitol might moderate this activity. PMID:19136828

  17. L (+)-lactic acid production by pellet-form Rhizopus oryzae NRRL 395 on biodiesel crude glycerol

    PubMed Central

    2013-01-01

    Background Given its availability and low price, glycerol derived from biodiesel industry has become an ideal feedstock for the production of fuels and chemicals. A solution to reduce the negative environmental problems and the cost of biodiesel is to use crude glycerol as carbon source for microbial growth media in order to produce valuable organic chemicals. In the present paper, crude glycerol was used as carbon substrate for production of L (+)-lactic acid using pelletized fungus R. oryzae NRRL 395 on batch fermentation. More, the experiments were conducted on media supplemented with inorganic nutrients and lucerne green juice. Results Crude and pure glycerols were first used to produce the highest biomass yield of R. oryzae NRRL 395. An enhanced lactic acid production then followed up using fed-batch fermentation with crude glycerol, inorganic nutrients and lucerne green juice. The optimal crude glycerol concentration for cultivating R. oryzae NRRL 395 was 75 g l-1, which resulted in a fungal biomass yield of 0.72 g g-1 in trial without lucerne green juice addition and 0.83 g g-1 in trial with lucerne green juice. The glycerol consumption rate was 1.04 g l-1 h-1 after 48 h in trial with crude glycerol 75 g l-1 while in trial with crude glycerol 10 g l-1 the lowest rate of 0.12 g l-1 h-1 was registered. The highest L (+)-lactic acid yield (3.72 g g-1) was obtained at the crude glycerol concentration of 75 g l-1 and LGJ 25 g l-1, and the concentration of lactic acid was approximately 48 g l-1. Conclusions This work introduced sustainable opportunities for L (+)-lactic acid production via R. oryzae NRRL 395 fermentation on biodiesel crude glycerol media. The results showed good fungal growth on crude glycerol at 75 g l-1 concentration with lucerne green juice supplementation of 25 g l-1. Lucerne green juice provided a good source of nutrients for crude glycerol fermentation, without needs for supplementation with inorganic nutrients

  18. Enhancement of lipid production and fatty acid profiling in Chlamydomonas reinhardtii, CC1010 for biodiesel production.

    PubMed

    Karpagam, R; Preeti, R; Ashokkumar, B; Varalakshmi, P

    2015-11-01

    Lipid from microalgae is one of the putative oil resources to facilitate the biodiesel production during this era of energy dissipation and environmental pollution. In this study, the key parameters such as biomass productivity, lipid productivity and lipid content were evaluated at the early stationary phase of Chlamydomonas reinhardtii, CC1010 cultivated in nutrient starved (nitrogen, phosphorous), glucose (0.05%, 0.1%, 0.15% and 0.2%) and vitamin B12 supplementation (0.001%, 0.002% and 0.003%) in Tris-Acetate-Phosphate (TAP) medium. The lipid content in nitrogen starved media was 61% which is 2.34 folds higher than nutrient sufficient TAP medium. Glucose supplementation has lead to proportional increase in biomass productivity with the increasing concentration of glucose whereas vitamin B12 supplementations had not shown any influence in lipid and biomass production. Further, fatty acid methyl ester (FAME) profiling of C. reinhardtii, CC 1010 has revealed more than 80% of total SFA (saturated fatty acid) and MUFA (mono unsaturated fatty acid) content. Quality checking parameters of biodiesel like cetane number, saponification value, iodine number and degree of unsaturation were analyzed and the biodiesel fuel properties were found to be appropriate as per the international standards, EN 14214 and ASTM D6751. Conclusively, among all the treatments, nitrogen starvation with 0.1% glucose supplementation had yielded high lipid content in C. reinhardtii, CC 1010. PMID:25838071

  19. [*C]octanoic acid breath test to measure gastric emptying rate of solids.

    PubMed

    Maes, B D; Ghoos, Y F; Rutgeerts, P J; Hiele, M I; Geypens, B; Vantrappen, G

    1994-12-01

    We have developed a breath test to measure solid gastric emptying using a standardized scrambled egg test meal (250 kcal) labeled with [14C]octanoic acid or [13C]octanoic acid. In vitro incubation studies showed that octanoic acid is a reliable marker of the solid phase. The breath test was validated in 36 subjects by simultaneous radioscintigraphic and breath test measurements. Nine healthy volunteers were studied after intravenous administration of 200 mg erythromycin and peroral administration of 30 mg propantheline, respectively. Erythromycin significantly enhanced gastric emptying, while propantheline significantly reduced gastric emptying rates. We conclude that the [*C]octanoic breath test is a promising and reliable test for measuring the gastric emptying rate of solids. PMID:7995200

  20. Factors influencing the rate of non-enzymatic activation of carboxylic and amino acids by ATP

    NASA Technical Reports Server (NTRS)

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1981-01-01

    The nonenzymatic formation of adenylate anhydrides of carboxylic and amino acids is discussed as a necessary step in the origin of the genetic code and protein biosynthesis. Results of studies are presented which have shown the rate of activation to depend on the pKa of the carboxyl group, the pH of the medium, temperature, the divalent metal ion catalyst, salt concentration, and the nature of the amino acid. In particular, it was found that of the various amino acids investigated, phenylalanine had the greatest affinity for the adenine derivatives adenosine and ATP. Results thus indicate that selective affinities between amino acids and nucleotides were important during prebiotic chemical evolution, and may have played a major role in the origin of protein synthesis and genetic coding.

  1. Biomass and production of amphipods in low alkalinity lakes affected by acid precipitation.

    PubMed

    France, R L

    1996-01-01

    Population biomass and production of the amphipod Hyalella azteca (Saussure) were found to be related to alkalinity (ranging from 0.2 to 58.1 mg liter(-1)) in 10 Canadian Shield lakes in south-central Ontario. Biomass and production of amphipods in the two lakes characterized by spring depressions of pH below 5.0 were found to be lower than those for populations inhabiting lakes that did not experience such acid pulses. The proportional biomass of amphipods in relation to the total littoral zoobenthos community was lower in lakes of low alkalinity than in circumneutral or hardwater lakes. Because production in these amphipod populations is known to depend closely on population abundance, the labour-intensive derivation of production rates yields relatively little information for biomonitoring that cannot be obtained from abundance data alone. PMID:15093505

  2. 30 CFR 250.1159 - May the Regional Supervisor limit my well or reservoir production rates?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... my well or reservoir production rates? (a) The Regional Supervisor may set a Maximum Production Rate... 30 Mineral Resources 2 2014-07-01 2014-07-01 false May the Regional Supervisor limit my well or reservoir production rates? 250.1159 Section 250.1159 Mineral Resources BUREAU OF SAFETY AND...

  3. 30 CFR 250.1159 - May the Regional Supervisor limit my well or reservoir production rates?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... my well or reservoir production rates? (a) The Regional Supervisor may set a Maximum Production Rate... 30 Mineral Resources 2 2012-07-01 2012-07-01 false May the Regional Supervisor limit my well or reservoir production rates? 250.1159 Section 250.1159 Mineral Resources BUREAU OF SAFETY AND...

  4. 76 FR 2930 - International Product Change-Global Expedited Package Services-Non- Published Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... Product Change--Global Expedited Package Services-- Non- Published Rates AGENCY: Postal Service\\TM... Commission to add Global Expedited Package Services-- Non-Published Rates 2 to the Competitive Products List... Service to add Global Expedited Package Services--Non-Published Rates, to the Competitive Products...

  5. 39 CFR 3010.2 - Types of rate adjustments for market dominant products.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Types of rate adjustments for market dominant... FOR MARKET DOMINANT PRODUCTS General Provisions § 3010.2 Types of rate adjustments for market dominant products. (a) There are four types of rate adjustments for market dominant products. A Type 1-A...

  6. Method for continuous production of aromatic carboxylic acid

    SciTech Connect

    Abrams, K.J.

    1988-12-20

    This patent describes a method for the continuous production of an aromatic carboxylic acid product in a pressurized oxidation reactor by liquid-phase, exothermic oxidation of an aromatic alkyl feed with an oxygen-containing gas, in the presence of an aromatic alkyl feed with an oxygen-containing gas, in the presence of an oxidation catalyst and in an aqueous monocarboxylic C/sub 2/ to C/sub 6/ aliphatic acid solvent medium, wherein the heat generated during the course of the oxidation is removed from the reactor by vaporization of a portion of the reaction medium and water, wherein the resulting vapors are condensed in part in a reflux loop externally of the oxidation reactor to produce a condensate and a gaseous phase, and wherein at least a portion of the condensate is returned to the oxidation reactor, the improvement comprising a method for controlling within desired limits the concentration of water in the oxidation reactor, which comprises: partitioning the vapors into a parallel condensate having a relatively lesser water-to-solvent weight ratio and a vapor phase having a relatively greater water-to-solvent weight ratio; returning the partial condensate directly to the oxidation reactor as a direct reflux stream; withdrawing the vapor phase from the reflux loop as a vapor stream; subjecting the withdrawn vapor stream to heat exchange while decreasing the vapor stream pressure to less than the oxidation reactor pressure to thereby produce an aqueous aliphatic acid stream having a water-to-solvent weight ratio greater than that of the direct reflux stream.

  7. Metabolic engineering of Pseudomonas putida for production of docosahexaenoic acid based on a myxobacterial PUFA synthase.

    PubMed

    Gemperlein, Katja; Zipf, Gregor; Bernauer, Hubert S; Müller, Rolf; Wenzel, Silke C

    2016-01-01

    Long-chain polyunsaturated fatty acids (LC-PUFAs) can be produced de novo via polyketide synthase-like enzymes known as PUFA synthases, which are encoded by pfa biosynthetic gene clusters originally discovered from marine microorganisms. Recently similar gene clusters were detected and characterized in terrestrial myxobacteria revealing several striking differences. As the identified myxobacterial producers are difficult to handle genetically and grow very slowly we aimed to establish heterologous expression platforms for myxobacterial PUFA synthases. Here we report the heterologous expression of the pfa gene cluster from Aetherobacter fasciculatus (SBSr002) in the phylogenetically distant model host bacteria Escherichia coli and Pseudomonas putida. The latter host turned out to be the more promising PUFA producer revealing higher production rates of n-6 docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). After several rounds of genetic engineering of expression plasmids combined with metabolic engineering of P. putida, DHA production yields were eventually increased more than threefold. Additionally, we applied synthetic biology approaches to redesign and construct artificial versions of the A. fasciculatus pfa gene cluster, which to the best of our knowledge represents the first example of a polyketide-like biosynthetic gene cluster modulated and synthesized for P. putida. Combination with the engineering efforts described above led to a further increase in LC-PUFA production yields. The established production platform based on synthetic DNA now sets the stage for flexible engineering of the complex PUFA synthase. PMID:26617065

  8. Fundamental Study on Temperature Dependence of Deposition Rate of Silicic Acid - 13270

    SciTech Connect

    Shinmura, Hayata; Niibori, Yuichi; Mimura, Hitoshi

    2013-07-01

    The dynamic behavior of the silicic acid is one of the key factors to estimate the condition of the repository system after the backfill. This study experimentally examined the temperature dependence of dynamic behavior of supersaturated silicic acid in the co-presence of solid phase, considering Na ions around the repository, and evaluated the deposition rate constant, k, of silicic acid by using the first-order reaction equation considering the specific surface area. The values of k were in the range of 1.0x10{sup -11} to 1.0x10{sup -9} m/s in the temperature range of 288 K to 323 K. The deposition rate became larger with increments of temperature under the Na ion free condition. Besides, in the case of Na ions 0.6 M, colloidal silicic acid decreased dramatically at a certain time. This means that the diameter of the colloidal silicic acid became larger than the pore size of filter (0.45 μm) due to bridging of colloidal silicic acid. Furthermore, this study estimated the range of altering area and the aperture of flow-path in various value of k corresponding to temperature by using advection-dispersion model. The concentration in the flow-path became lower with increments of temperature, and when the value of k is larger than 1.0x10{sup -11} m/s, the deposition range of supersaturated silicic acid was estimated to be less than 20 m around the repository. In addition, the deposition of supersaturated silicic acid led the decrement of flow-path aperture, which was remarkable under the condition of relatively high temperature. Such a clogging in flow paths is expected as a retardation effect of radionuclides. (authors)

  9. 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

  10. Determination of optimal lot size and production rate for multi-production channels with limited capacity

    NASA Astrophysics Data System (ADS)

    Huang, Yeu-Shiang; Wang, Ruei-Pei; Ho, Jyh-Wen

    2015-07-01

    Due to the constantly changing business environment, producers often have to deal with customers by adopting different procurement policies. That is, manufacturers confront not only predictable and regular orders, but also unpredictable and irregular orders. In this study, from the perspective of upstream manufacturers, both regular and irregular orders are considered in coping with the situation in which an uncertain demand is faced by the manufacturer, and a capacity confirming mechanism is used to examine such demand. If the demand is less than or equal to the capacity of the ordinary production channel, the general supply channel is utilised to fully account for the manufacturing process, but if the demand is greater than the capacity of the ordinary production channel, the contingency production channel would be activated along with the ordinary channel to satisfy the upcoming high demand. Besides, the reproductive property of the probability distribution is employed to represent the order quantity of the two types of demand. Accordingly, the optimal production rates and lot sizes for both channels are derived to provide managers with insights for further production planning.

  11. Fed-batch fermentation for enhanced lactic acid production from glucose/xylose mixture without carbon catabolite repression.

    PubMed

    Abdel-Rahman, Mohamed Ali; Xiao, Yaotian; Tashiro, Yukihiro; Wang, Ying; Zendo, Takeshi; Sakai, Kenji; Sonomoto, Kenji

    2015-02-01

    There has been tremendous growth in the production of optically pure l-lactic acid from lignocellulose-derived sugars. In this study, Enterococcus mundtii QU 25 was used to ferment a glucose/xylose mixture to l-lactic acid. Maintenance of the xylose concentration at greater than 10 g/L achieved homo-lactic acid fermentation and reduced the formation of byproducts. Furthermore, carbon catabolite repression (CCR) was avoided by maintaining the glucose concentration below 25 g/L; therefore, initial concentrations of 25 g/L glucose and 50 g/L xylose were selected. Supplementation with 5 g/L yeast extract enhanced the maximum xylose consumption rate and consequently increased lactic acid production and productivity. Finally, a 129 g/L lactic acid without byproducts was obtained with a maximum lactic acid productivity of 5.60 g/(L·h) in fed-batch fermentation with feeding a glucose/xylose mixture using ammonium hydroxide as the neutralizing agent. These results indicate a potential for lactic acid production from glucose and xylose as the main components of lignocellulosic biomasses. PMID:25280397

  12. 27 CFR 19.246 - Computing the effective tax rate for a product.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Computing the effective... Spirits Taxes Effective Tax Rates § 19.246 Computing the effective tax rate for a product. (a) How to compute effective tax rates. In order to determine the effective tax rate for a distilled spirits...

  13. 27 CFR 19.246 - Computing the effective tax rate for a product.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Computing the effective... Spirits Taxes Effective Tax Rates § 19.246 Computing the effective tax rate for a product. (a) How to compute effective tax rates. In order to determine the effective tax rate for a distilled spirits...

  14. 27 CFR 19.246 - Computing the effective tax rate for a product.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Computing the effective... Spirits Taxes Effective Tax Rates § 19.246 Computing the effective tax rate for a product. (a) How to compute effective tax rates. In order to determine the effective tax rate for a distilled spirits...

  15. 27 CFR 19.246 - Computing the effective tax rate for a product.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Computing the effective... Spirits Taxes Effective Tax Rates § 19.246 Computing the effective tax rate for a product. (a) How to compute effective tax rates. In order to determine the effective tax rate for a distilled spirits...

  16. Mannitol production by lactic acid bacteria grown in supplemented carob syrup.

    PubMed

    Carvalheiro, Florbela; Moniz, Patrícia; Duarte, Luís C; Esteves, M Paula; Gírio, Francisco M

    2011-01-01

    Detailed kinetic and physiological characterisation of eight mannitol-producing lactic acid bacteria, Leuconostoc citreum ATCC 49370, L. mesenteroides subsp. cremoris ATCC19254, L. mesenteroides subsp. dextranicum ATCC 19255, L. ficulneum NRRL B-23447, L. fructosum NRRL B-2041, L. lactis ATCC 19256, Lactobacillus intermedius NRRL 3692 and Lb. reuteri DSM 20016, was performed using a carob-based culture medium, to evaluate their different metabolic capabilities. Cultures were thoroughly followed for 30 h to evaluate consumption of sugars, as well as production of biomass and metabolites. All strains produced mannitol at high yields (>0.70 g mannitol/g fructose) and volumetric productivities (>1.31 g/l h), and consumed fructose and glucose simultaneously, but fructose assimilation rate was always higher. The results obtained enable the studied strains to be divided mainly into two groups: one for which glucose assimilation rates were below 0.78 g/l h (strains ATCC 49370, ATCC 19256 and ATCC 19254) and the other for which they ranged between 1.41 and 1.89 g/l h (strains NRRL B-3692, NRRL B-2041, NRRL B-23447 and DSM 20016). These groups also exhibited different mannitol production rates and yields, being higher for the strains with faster glucose assimilation. Besides mannitol, all strains also produced lactic acid and acetic acid. The best performance was obtained for L. fructosum NRRL B-2041, with maximum volumetric productivity of 2.36 g/l h and the highest yield, stoichiometric conversion of fructose to mannitol. PMID:20820868

  17. INTERWELL CONNECTIVITY AND DIAGNOSIS USING CORRELATION OF PRODUCTION AND INJECTION RATE DATA IN HYDROCARBON PRODUCTION

    SciTech Connect

    Jerry L. Jensen; Larry W. Lake; Thang D. Bui; Ali Al-Yousef; Pablo Gentil

    2004-08-01

    This report details much of the progress on inferring interwell communication from well rate fluctuations. The goal of the project was to investigate the feasibility of inferring reservoir properties through weights derived from correlations between injection and production rates. We have focused on and accomplished the following items: (1) We have identified two possible causes for the source of negative weights. These are colinearity between injectors, and nonstationarity of be production data. (2) Colinearity has been addressed through ridge regression. Though there is much to be done here, such regression represents a trade-off between a minimum variance estimator and a biased estimator. (3) We have applied the ridge regression and the original Albertoni procedure to field data from the Magnus field. (4) The entire procedure (with several options) has been codified as a spreadsheet add-in. (5) Finally, we have begun, and report on, an extension of the method to predicting oil rates. Successful completion of these items will constitute the bulk of the final year's report.

  18. Highly efficient production of optically pure l-lactic acid from corn stover hydrolysate by thermophilic Bacillus coagulans.

    PubMed

    Ma, Kedong; Hu, Guoquan; Pan, Liwei; Wang, Zichao; Zhou, Yi; Wang, Yanwei; Ruan, Zhiyong; He, Mingxiong

    2016-11-01

    A thermophilic strain Bacillus coagulans (NBRC 12714) was employed to produce l-lactic acid from corn stover hydrolysate in membrane integrated continuous fermentation. The strain NBRC 12714 metabolized glucose and xylose by the Embden-Meyerhof-Parnas pathway (EMP) and the pentose phosphate pathway (PPP), producing l-lactic acid with optical purity >99.5%. The overall l-lactic acid titer of 92g/l with a yield of 0.91g/g and a productivity of 13.8g/l/h were achieved at a dilution rate of 0.15h(-1). The productivity obtained was 1.6-fold than that of conventional continuous fermentation without cell recycling, and also was the highest among the relevant studies ever reported. These results indicated that the process developed had great potential for economical industrial production of l-lactic acid from lignocellulosic biomass. PMID:27479802

  19. Production of 3-hydroxypropionic acid from glycerol by acid tolerant Escherichia coli.

    PubMed

    Sankaranarayanan, Mugesh; Ashok, Somasundar; Park, Sunghoon

    2014-07-01

    The biological production of 3-hydroxypropionic acid (3-HP) has attracted significant attention because of its industrial importance. The low titer, yield and productivity, all of which are related directly or indirectly to the toxicity of 3-HP, have limited the commercial production of 3-HP. The aim of this study was to identify and select a 3-HP tolerant Escherichia coli strain among nine strains reported to produce various organic acids efficiently at high titer. When transformed with heterologous glycerol dehydratase, reactivase and aldehyde dehydrogenase, all nine E. coli strains produced 3-HP from glycerol but the level of 3-HP production, protein expression and activities of the important enzymes differed significantly according to the strain. Two E. coli strains, W3110 and W, showed higher levels of growth than the others in the presence of 25 g/L 3-HP. In the glycerol fed-batch bioreactor experiments, the recombinant E. coli W produced a high level of 3-HP at 460 ± 10 mM (41.5 ± 1.1 g/L) in 48 h with a yield of 31 % and a productivity of 0.86 ± 0.05 g/L h. In contrast, the recombinant E. coli W3110 produced only 180 ± 8.5 mM 3-HP (15.3 ± 0.8 g/L) in 48 h with a yield and productivity of 26 % and 0.36 ± 0.02 g/L h, respectively. This shows that the tolerance to and the production of 3-HP differ significantly among the well-known, similar strains of E. coli. The titer and productivity obtained with E. coli W were the highest reported thus far for the biological production of 3-HP from glycerol by E. coli. PMID:24788379

  20. Comparison of parameterized nitric acid rainout rates using a coupled stochastic-photochemical tropospheric model

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.; Thompson, Anne M.; Owens, Melody A.; Herwehe, Jerold A.

    1989-01-01

    A major tropospheric loss of soluble species such as nitric acid results from scavenging by water droplets. Several theoretical formulations have been advanced which relate an effective time-independent loss rate for soluble species to statistical properties of precipitation such as the wet fraction and length of a precipitation cycle. In this paper, various 'effective' loss rates that have been proposed are compared with the results of detailed time-dependent model calculations carried out over a seasonal time scale. The model is a stochastic precipitation model coupled to a tropospheric photochemical model. The results of numerous time-dependent seasonal model runs are used to derive numerical values for the nitric acid residence time for several assumed sets of preciptation statistics. These values are then compared with the results obtained by utilizing theoretical 'effective' loss rates in time-independent models.

  1. Enhanced capture rate for haze defects in production wafer inspection

    NASA Astrophysics Data System (ADS)

    Auerbach, Ditza; Shulman, Adi; Rozentsvige, Moshe

    2010-03-01

    Photomask degradation via haze defect formation is an increasing troublesome yield problem in the semiconductor fab. Wafer inspection is often utilized to detect haze defects due to the fact that it can be a bi-product of process control wafer inspection; furthermore, the detection of the haze on the wafer is effectively enhanced due to the multitude of distinct fields being scanned. In this paper, we demonstrate a novel application for enhancing the wafer inspection tool's sensitivity to haze defects even further. In particular, we present results of bright field wafer inspection using the on several photo layers suffering from haze defects. One way in which the enhanced sensitivity can be achieved in inspection tools is by using a double scan of the wafer: one regular scan with the normal recipe and another high sensitivity scan from which only the repeater defects are extracted (the non-repeater defects consist largely of noise which is difficult to filter). Our solution essentially combines the double scan into a single high sensitivity scan whose processing is carried out along two parallel routes (see Fig. 1). Along one route, potential defects follow the standard recipe thresholds to produce a defect map at the nominal sensitivity. Along the alternate route, potential defects are used to extract only field repeater defects which are identified using an optimal repeater algorithm that eliminates "false repeaters". At the end of the scan, the two defect maps are merged into one with optical scan images available for all the merged defects. It is important to note, that there is no throughput hit; in addition, the repeater sensitivity is increased relative to a double scan, due to a novel runtime algorithm implementation whose memory requirements are minimized, thus enabling to search a much larger number of potential defects for repeaters. We evaluated the new application on photo wafers which consisted of both random and haze defects. The evaluation procedure

  2. Rates and mechanisms of fatty acid degradation in oxic and anoxic coastal marine sediments of Long Island Sound, New York, USA

    NASA Astrophysics Data System (ADS)

    Sun, Ming-Yi; Wakeham, Stuart G.; Lee, Cindy

    1997-01-01

    The rates and pathways of labile organic matter degradation significantly affect the cycling of organic carbon and nutrients in coastal sediments. In this study, we measured degradation rate constants of saturated and unsaturated fatty acids by incubating radiolabeled 1- 14C-palmitic (16:0) and 1- 14C-oleic (18:1) acids and an unlabeled plankton mixture in oxic and anoxic sediments from Long Island Sound (LIS) under laboratory-controlled conditions. Rate constants for degradation of 16:0 and 18:1 fatty acids were higher in oxic sediments than in anoxic sediments. Degradation of the unsaturated 18:1 acid in anoxic sediments was two times faster than for 16:0, while there was little difference between the two fatty acids in oxic sediments. The incubation results clearly showed that fatty acids degrade through multiple pathways in both oxic and anoxic sediments. About 80-90% of the label was lost from the incubated sediments (presumably as 14CO 2 or other volatile products), and 5-10% was incorporated into the sediment matrix. Both degradation and incorporation into the sediment matrix were slightly greater under oxic conditions. A small part (5-10%) of the label was incorporated into what are presumed to be metabolic products. A higher percentage of this incorporation occurred under anoxic conditions, implying that anaerobic bacteria are less efficient at degrading the labeled fatty acid to volatile products such as CO 2. In the oxic sediments, more oleic than palmitic acid was converted into intermediate metabolites, indicating that the unsaturated fatty acid was degraded less efficiently. There was little difference in formation of metabolites between oleic and palmitic acids under anoxic conditions. The seasonal distributions of palmitic and oleic acids at two coastal LIS sites with distinctive oxygen content were modeled to yield degradation rate constants for these two fatty acids. The comparison between fatty acid degradation rate constants derived from

  3. Entropy production rates from viscous flow calculations. I - A turbulent boundary layer flow

    NASA Astrophysics Data System (ADS)

    Moore, J.; Moore, J. G.

    1983-03-01

    A procedure for obtaining entropy production rates from viscous flow calculations is described. The method is based on process thermodynamics; it allows loss production to be calculated in 'irreversible equilibrium processes'. The two-dimensional turbulent boundary layer of Samuel and Joubert is considered. Mean rates of entropy production are evaluated from measured data using rates of dissipation and rates of increase of turbulence kinetic energy. Calculations performed with the Moore Cascade Flow Program give good agreement with mean rates of entropy production and reveal details of the distribution of entropy production throughout the boundary layer.

  4. Optimal Spray Application Rates for Ornamental Nursery Liner Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spray deposition and coverage at different application rates for nursery liners of different sizes were investigated to determine the optimal spray application rates. Experiments were conducted on two and three-year old red maple liners. A traditional hydraulic sprayer with vertical booms was used t...

  5. Effect of phenolic acids of microbial origin on production of reactive oxygen species in mitochondria and neutrophils

    PubMed Central

    2012-01-01

    Background Several low-molecular-weight phenolic acids are present in the blood of septic patients at high levels. The microbial origin of the most of phenolic acids in the human body was shown previously, but pathophysiological role of the phenolic acids is not clear. Sepsis is associated with the excessive production of reactive oxygen species (ROS) in both the circulation and the affected organs. In this work the influence of phenolic acids on ROS production in mitochondria and neutrophils was investigated. Methods ROS production in mitochondria and neutrophils was determined by MCLA- and luminol-dependent chemiluminescence. The rate of oxygen consumption by mitochondria was determined polarographically. The difference of electric potentials on the inner mitochondrial membrane was registered using a TPP+-selective electrode. The formation of phenolic metabolites in monocultures by the members of the main groups of the anaerobic human microflora and aerobic pathogenic bacteria was investigated by the method of gas chromatography–mass spectrometry. Results All phenolic acids had impact on mitochondria and neutrophils, the main producers of ROS in tissues and circulation. Phenolic acids (benzoic and cinnamic acids) producing the pro-oxidant effect on mitochondria inhibited ROS formation in neutrophils. Their effect on mitochondria was abolished by dithiothreitol (DTT). Phenyllactate and p-hydroxyphenyllactate decreased ROS production in both mitochondria and neutrophils. Bifidobacteria and lactobacilli produced in vitro considerable amounts of phenyllactic and p-hydroxyphenyllactic acids, Clostridia s. produced great quantities of phenylpropionic and p-hydroxyphenylpropionic acids, p-hydroxyphenylacetic acid was produced by Pseudomonas aeruginosa and Acinetobacter baumanii; and benzoic acid, by Serratia marcescens. Conclusions The most potent activators of ROS production in mitochondria are phenolic acids whose effect is mediated via the interaction with thiol

  6. Contribution of the tricarboxylic acid (TCA) cycle and the glyoxylate shunt in Saccharomyces cerevisiae to succinic acid production during dough fermentation.

    PubMed

    Rezaei, Mohammad N; Aslankoohi, Elham; Verstrepen, Kevin J; Courtin, Christophe M

    2015-07-01

    Succinic acid produced by yeast during bread dough fermentation can significantly affect the rheological properties of the dough. By introducing mutations in the model S288C yeast strain, we show that the oxidative pathway of the TCA cycle and the glyoxylate shunt contribute significantly to succinic acid production during dough fermentation. More specifically, deletion of ACO1 and double deletion of ACO1 and ICL1 resulted in a 36 and 77% decrease in succinic acid levels in fermented dough, respectively. Similarly, double deletion of IDH1 and IDP1 decreased succinic acid production by 85%, while also affecting the fermentation rate. By contrast, double deletion of SDH1 and SDH2 resulted in a two-fold higher succinic acid accumulation compared to the wild-type. Deletion of fumarate reductase activity (FRD1 and OSM1) in the reductive pathway of the TCA cycle did not affect the fermentation rate and succinic acid production. The changes in the levels of succinic acid produced by mutants Δidh1Δidp1 (low level) and Δsdh1Δsdh2 (high level) in fermented dough only resulted in small pH differences, reflecting the buffering capacity of dough at a pH of around 5.1. Moreover, Rheofermentometer analysis using these mutants revealed no difference in maximum dough height and gas retention capacity with the dough prepared with S288C. The impact of the changed succinic acid profile on the organoleptic or antimicrobial properties of bread remains to be demonstrated. PMID:25828707

  7. Improved estimates of environmental copper release rates from antifouling products.

    PubMed

    Finnie, Alistair A

    2006-01-01

    The US Navy Dome method for measuring copper release rates from antifouling paint in-service on ships' hulls can be considered to be the most reliable indicator of environmental release rates. In this paper, the relationship between the apparent copper release rate and the environmental release rate is established for a number of antifouling coating types using data from a variety of available laboratory, field and calculation methods. Apart from a modified Dome method using panels, all laboratory, field and calculation methods significantly overestimate the environmental release rate of copper from antifouling coatings. The difference is greatest for self-polishing copolymer antifoulings (SPCs) and smallest for certain erodible/ablative antifoulings, where the ASTM/ISO standard and the CEPE calculation method are seen to typically overestimate environmental release rates by factors of about 10 and 4, respectively. Where ASTM/ISO or CEPE copper release rate data are used for environmental risk assessment or regulatory purposes, it is proposed that the release rate values should be divided by a correction factor to enable more reliable generic environmental risk assessments to be made. Using a conservative approach based on a realistic worst case and accounting for experimental uncertainty in the data that are currently available, proposed default correction factors for use with all paint types are 5.4 for the ASTM/ISO method and 2.9 for the CEPE calculation method. Further work is required to expand this data-set and refine the correction factors through correlation of laboratory measured and calculated copper release rates with the direct in situ environmental release rate for different antifouling paints under a range of environmental conditions. PMID:17110352

  8. Development of a two-step process for production of 3-hydroxypropionic acid from glycerol using Klebsiella pneumoniae and Gluconobacter oxydans.

    PubMed

    Zhao, Li; Lin, Jinping; Wang, Hualei; Xie, Jingli; Wei, Dongzhi

    2015-12-01

    In this work, a two-step process was developed for the production of 3-hydroxypropionic acid from glycerol. In the first step, glycerol was converted to 1,3-propanediol by Klebsiella pneumonia. In the second step, the 1,3-propanediol was converted into 3-hydroxypropionic acid by Gluconobacter oxydans. In a 7.0 L bioreactor, the whole process took 54 h, consumed 480 g glycerol and produced 242 g 3-hydroxypropionic acid. The conversion rate of glycerol to 3-hydroxypropionic acid was 50.4 % (g g(-1)). The final concentration of 3-hydroxypropionic acid arrived 60.5 g L(-1). The process was effective for 3-HP production from glycerol and it might provide a new approach to the biosynthesis of 3-HP from a cheap starting material. Moreover, in this paper, it was first reported that the by-product of 3-hydroxypropionic acid production from 1,3-propandeiol was acrylic acid. PMID:26481922

  9. World Bank Atlas: Population, Per Capita Product and Growth Rates.

    ERIC Educational Resources Information Center

    World Bank, Washington, DC.

    The ninth edition of the World Bank Atlas shows estimates of population, gross national product, and per capita production of 189 countries and territories for 1972. The data presented in the atlas are the result of the work of the World Bank Group whose major purpose is to provide both financial and technical assistance and to improve the living…

  10. 78 FR 39784 - International Product Change-Priority Mail International Regional Rate Boxes-Non-Published Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-02

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE International Product Change--Priority Mail International Regional Rate Boxes--Non-Published Rates AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY: The Postal Service hereby gives notice that it has filed a...

  11. 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

  12. Large-scale production of anhydrous nitric acid and nitric acid solutions of dinitrogen pentoxide

    DOEpatents

    Harrar, Jackson E.; Quong, Roland; Rigdon, Lester P.; McGuire, Raymond R.

    2001-01-01

    A method and apparatus are disclosed for a large scale, electrochemical production of anhydrous nitric acid and N.sub.2 O.sub.5. The method includes oxidizing a solution of N.sub.2 O.sub.4 /aqueous-HNO.sub.3 at the anode, while reducing aqueous HNO.sub.3 at the cathode, in a flow electrolyzer constructed of special materials. N.sub.2 O.sub.4 is produced at the cathode and may be separated and recycled as a feedstock for use in the anolyte. The process is controlled by regulating the electrolysis current until the desired products are obtained. The chemical compositions of the anolyte and catholyte are monitored by measurement of the solution density and the concentrations of N.sub.2 O.sub.4.

  13. 50 CFR Table 3 to Part 679 - Product Recovery Rates for Groundfish Species and Conversion Rates for Pacific Halibut

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Species and Conversion Rates for Pacific Halibut 3 Table 3 to Part 679 Wildlife and Fisheries FISHERY... Rates for Groundfish Species and Conversion Rates for Pacific Halibut Species code FMP Species Product... cut 8H&G east cut 10H&G w/o tail 11Kirimi 12Salted & Split 13 Wings 14Roe 110 Pacific Cod 1.00 0.98...

  14. Gluconeogenesis is associated with high rates of tricarboxylic acid and pyruvate cycling in fasting northern elephant seals.

    PubMed

    Champagne, Cory D; Houser, Dorian S; Fowler, Melinda A; Costa, Daniel P; Crocker, Daniel E

    2012-08-01

    Animals that endure prolonged periods of food deprivation preserve vital organ function by sparing protein from catabolism. Much of this protein sparing is achieved by reducing metabolic rate and suppressing gluconeogenesis while fasting. Northern elephant seals (Mirounga angustirostris) endure prolonged fasts of up to 3 mo at multiple life stages. During these fasts, elephant seals maintain high levels of activity and energy expenditure associated with breeding, reproduction, lactation, and development while maintaining rates of glucose production typical of a postabsorptive mammal. Therefore, we investigated how fasting elephant seals meet the requirements of glucose-dependent tissues while suppressing protein catabolism by measuring the contribution of glycogenolysis, glycerol, and phosphoenolpyruvate (PEP) to endogenous glucose production (EGP) during their natural 2-mo postweaning fast. Additionally, pathway flux rates associated with the tricarboxylic acid (TCA) cycle were measured specifically, flux through phosphoenolpyruvate carboxykinase (PEPCK) and pyruvate cycling. The rate of glucose production decreased during the fast (F(1,13) = 5.7, P = 0.04) but remained similar to that of postabsorptive mammals. The fractional contributions of glycogen, glycerol, and PEP did not change with fasting; PEP was the primary gluconeogenic precursor and accounted for ∼95% of EGP. This large contribution of PEP to glucose production occurred without substantial protein loss. Fluxes through the TCA cycle, PEPCK, and pyruvate cycling were higher than reported in other species and were the most energetically costly component of hepatic carbohydrate metabolism. The active pyruvate recycling fluxes detected in elephant seals may serve to rectify gluconeogeneic PEP production during restricted anaplerotic inflow in these fasting-adapted animals. PMID:22673783

  15. Integrated Production of Xylonic Acid and Bioethanol from Acid-Catalyzed Steam-Exploded Corn Stover.

    PubMed

    Zhu, Junjun; Rong, Yayun; Yang, Jinlong; Zhou, Xin; Xu, Yong; Zhang, Lingling; Chen, Jiahui; Yong, Qiang; Yu, Shiyuan

    2015-07-01

    High-efficiency xylose utilization is one of the restrictive factors of bioethanol industrialization. However, xylonic acid (XA) as a new bio-based platform chemical can be produced by oxidation of xylose with microbial. So, an applicable technology of XA bioconversion was integrated into the process of bioethanol production. After corn stover was pretreated with acid-catalyzed steam-explosion, solid and liquid fractions were obtained. The liquid fraction, also named as acid-catalyzed steam-exploded corn stover (ASC) prehydrolyzate (mainly containing xylose), was catalyzed with Gluconobacter oxydans NL71 to prepare XA. After 72 h of bioconversion of concentrated ASC prehydrolyzate (containing 55.0 g/L of xylose), the XA concentration reached a peak value of 54.97 g/L, the sugar utilization ratio and XA yield were 94.08 and 95.45 %, respectively. The solid fraction was hydrolyzed to produce glucose with cellulase and then fermented with Saccharomyces cerevisiae NL22 to produce ethanol. After 18 h of fermentation of concentrated enzymatic hydrolyzate (containing 86.22 g/L of glucose), the ethanol concentration reached its highest value of 41.48 g/L, the sugar utilization ratio and ethanol yield were 98.72 and 95.25 %, respectively. The mass balance showed that 1 t ethanol and 1.3 t XA were produced from 7.8 t oven dry corn stover. PMID:25947618

  16. Improvement of glucose uptake rate and production of target chemicals by overexpressing hexose transporters and transcriptional activator Gcr1 in Saccharomyces cerevisiae.

    PubMed

    Kim, Daehee; Song, Ji-Yoon; Hahn, Ji-Sook

    2015-12-01

    Metabolic engineering to increase the glucose uptake rate might be beneficial to improve microbial production of various fuels and chemicals. In this study, we enhanced the glucose uptake rate in Saccharomyces cerevisiae by overexpressing hexose transporters (HXTs). Among the 5 tested HXTs (Hxt1, Hxt2, Hxt3, Hxt4, and Hxt7), overexpression of high-affinity transporter Hxt7 was the most effective in increasing the glucose uptake rate, followed by moderate-affinity transporters Hxt2 and Hxt4. Deletion of STD1 and MTH1, encoding corepressors of HXT genes, exerted differential effects on the glucose uptake rate, depending on the culture conditions. In addition, improved cell growth and glucose uptake rates could be achieved by overexpression of GCR1, which led to increased transcription levels of HXT1 and ribosomal protein genes. All genetic modifications enhancing the glucose uptake rate also increased the ethanol production rate in wild-type S. cerevisiae. Furthermore, the growth-promoting effect of GCR1 overexpression was successfully applied to lactic acid production in an engineered lactic acid-producing strain, resulting in a significant improvement of productivity and titers of lactic acid production under acidic fermentation conditions. PMID:26431967

  17. Acid hydrolysis of sweet potato for ethanol production

    SciTech Connect

    Kim, K.; Hamdy, M.K.

    1985-01-01

    Studies were conducted to establish optimal conditions for the acid hydrolysis of sweet potato for maximal ethanol yield. The starch contents of two sweet potato cultivars (Georgia Red and TG-4), based on fresh weight, were 21.1 +/- 0.6% and 27.5 +/- 1.6%, respectively. The results of acid hydrolysis experiments showed the following: (1) both hydrolysis rate and hydroxymethylfurfural (HMF) concentration were a function of HCL concentration, temperature, and time; (2) the reducing sugars were rapidly formed with elevated concentrations of HCl and temperature, but also destroyed quickly; and (3) HMF concentration increased significantly with the concentration of HCl, temperature, and hydrolysis time. Maximum reducing sugar value of 84.2 DE and 0.056% HMF (based on wet weight) was achieved after heating 8% SPS for 15 min in 1N HCl at 110/sup 0/C. Degraded 8% SPS (1N HCl, 97/sup 0/C for 20 min or 110/sup 0/C for 10 min) was utilized as substrate for ethanol fermentation and 3.8% ethanol (v/v) was produced from 1400 mL fermented wort. This is equal to 41.6 g ethanol (200 proof) from 400 g of fresh sweet potato tuber (Georgia Red) or an ethanol yield potential of 431 gal of 200-proof ethanol/acre (from 500 bushel tubers/acre).

  18. Carob pod water extracts as feedstock for succinic acid production by Actinobacillus succinogenes 130Z.

    PubMed

    Carvalho, Margarida; Roca, Christophe; Reis, Maria A M

    2014-10-01

    Carob pods are a by-product of locust bean gum industry containing more than 50% (w/w) sucrose, glucose and fructose. In this work, carob pod water extracts were used, for the first time, for succinic acid production by Actinobacillus succinogenes 130Z. Kinetic studies of glucose, fructose and sucrose consumption as individual carbon sources till 30g/L showed no inhibition on cell growth, sugar consumption and SA production rates. Sugar extraction from carob pods was optimized varying solid/liquid ratio and extraction time, maximizing sugar recovery while minimizing the extraction of polyphenols. Batch fermentations containing 10-15g/L total sugars resulted in a maximum specific SA production rate of 0.61Cmol/Cmol X.h, with a yield of 0.55Cmol SA/Cmol sugar and a volumetric productivity of 1.61g SA/L.h. Results demonstrate that carob pods can be a promising low cost feedstock for bio-based SA production. PMID:25164341

  19. The effects of energy expenditure rate on work productivity performance at different levels of production standard time

    PubMed Central

    Nur, Nurhayati Mohd; Dawal, Siti Zawiah Md; Dahari, Mahidzal; Sanusi, Junedah

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of energy expenditure rate on work productivity performance at different levels of production standard time. [Subjects and Methods] Twenty industrial workers performed repetitive tasks at three different levels of production standard time, normal, hard, and very hard. Work productivity and energy expenditure rate were recorded during the experimental tasks. [Results] The work productivity target was not attainable for the hard and very hard production standard times. This was attributed to the energy expenditure rate, which increased as the level of production standard time became harder. The percentage change in energy expenditure rate for the very hard level (32.5%) relative to the normal level was twice that of the hard level (15.5%), indicating a higher risk of work-related musculoskeletal disorders for the harder production standard time. The energy expenditure rate for the very hard production standard time (1.36 kcal/min) was found to exceed the maximum energy expenditure rate recommended for light repetitive tasks involving both arms (1.2 kcal/min). [Conclusion] The present study shows that working with an energy expenditure rate that is either equal to or above the maximum energy expenditure rate of the tasks results in decreased work productivity performance due to the onset of physical fatigue and a higher risks of work-related musculoskeletal disorders. PMID:26357421

  20. Determination of Critical Point of pO2 Level in the Production of Lactic Acid by Lactobacillus rhamnosus

    NASA Astrophysics Data System (ADS)

    Mel, Maizirwan; Karim, Mohamed Ismail Abdul; Salleh, Mohamad Ramlan Mohamed; Abdullah, Rohane

    The study was conducted to determine the critical point of pO2 level in the production of lactic acid by Lactobacillus rhamnosus. The fermentation process was successfully carried out in laboratory scale fermenter/bioreactor using different pO2 level (the main parameter that significantly affects the growth of L. rhamnosus and lactic acid production) together with two other parameters; the agitation rate and pH. From the result, it was observed that the best production of lactic acid with the concentration of 16.85 g L-1 or 1.68% production yield has been obtained at the operating parameters of 5% pO2 level, agitation speed of 100 rpm and sample pH 6. The critical point of pO2 was found to be between 5 and 10%.

  1. Chemical stabilization of cadmium in acidic soil using alkaline agronomic and industrial by-products.

    PubMed

    Chang, Yao-Tsung; Hsi, Hsing-Cheng; Hseu, Zeng-Yei; Jheng, Shao-Liang

    2013-01-01

    In situ immobilization of heavy metals using reactive or stabilizing materials is a promising solution for soil remediation. Therefore, four agronomic and industrial by-products [wood biochar (WB), crushed oyster shell (OS), blast furnace slag (BFS), and fluidized-bed crystallized calcium (FBCC)] and CaCO3 were added to acidic soil (Cd = 8.71 mg kg(-1)) at the rates of 1%, 2%, and 4% and incubated for 90 d. Chinese cabbage (Brassica chinensis L.) was then planted in the soil to test the Cd uptake. The elevation in soil pH caused by adding the by-products produced a negative charge on the soil surface, which enhanced Cd adsorption. Consequently, the diethylenetriamine pentaacetic acid (DTPA)-extractable Cd content decreased significantly (P < 0.05) in the incubated soil. These results from the sequential extraction procedure indicated that Cd converted from the exchangeable fraction to the carbonate or Fe-Mn oxide fraction. The long-term effectiveness of Cd immobilization caused by applying the 4 by-products was much greater than that caused by applying CaCO3. Plant shoot biomass clearly increased because of the by-product soil amendment. Cd concentration in the shoots was < 10.0 mg kg(-1) following by-product application, as compared to 24 mg kg(-1) for plants growing in unamended soil. PMID:23947715

  2. Furfural production from Eucalyptus wood using an Acidic Ionic Liquid.

    PubMed

    Peleteiro, Susana; Santos, Valentín; Garrote, Gil; Parajó, Juan Carlos

    2016-08-01

    Eucalyptus globulus wood samples were treated with hot, compressed water to separate hemicelluloses (as soluble saccharides) from a solid phase mainly made up of cellulose and lignin. The liquid phase was dehydrated, and the resulting solids (containing pentoses as well as poly- and oligo- saccharides made up of pentoses) were dissolved and reacted in media containing an Acidic Ionic Liquid (1-butyl-3-methylimidazolium hydrogen sulfate) and a co-solvent (dioxane). The effects of the reaction time on the product distribution were studied at temperatures in the range 120-170°C for reaction times up to 8h, and operational conditions leading to 59.1% conversion of the potential substrates (including pentoses and pentose structural units in oligo- and poly- saccharides) into furfural were identified. PMID:27112846

  3. Role of solid acid catalysts in bio diesel production.

    PubMed

    Shivayogimath, C B; Sunita, G; Manoj Kumar, B

    2009-07-01

    Biodiesel is gaining importance as an alternate source of attractive fuel because of depleting fossil fuel resources. It is produced by trans-esterification, in which oil or fat reacts with a monohydric alcohol in presence of a catalyst. In the present work, trans-esterification of sunflower oil with methanol is carried out by using zirconia supported isopoly and heteropoly tungstates (HPAs) as catalysts. Effects of reaction parameters, such as catalyst types and its concentration, molar ratio of sunflower oil to methanol, reaction temperature and time, have been optimized to get higher conversion of sunflower oil and the product distribution of fatty acid methyl esters (FAME) in the trans-esterfication reaction. PMID:21117436

  4. Origin of haloacetic acids in milk and dairy products.

    PubMed

    Cardador, Maria Jose; Gallego, Mercedes

    2016-04-01

    Haloacetic acids (HAAs) are formed during the process of water disinfection. Therefore their presence in foods can be correlated with the addition of or contact with treated water. To determine the origin of HAAs in milk and dairy products, firstly a chromatographic method was developed for their determination. The sample treatment involves deproteination of milk followed by derivatization/extraction of the HAAs in the supernatant. About 20% of the foods analyzed contained two HAAs - which in no case exceeded 2 μg L(-1), that can be ascribed to contamination from sanitizers usually employed in the dairy industry. The process of boiling tap water (containing HAAs) for the preparation of powdered infant formula did not remove them; therefore it would be advisable to prepare this type of milk with mineral water (free of HAAs). In addition, it is possible to establish if the milk has been adulterated with treated water through the determination of HAAs. PMID:26593550

  5. The Rate of Expanded Inner Speech During Spontaneous Sentence Productions.

    PubMed

    Netsell, Ronald; Kleinsasser, Steven; Daniel, Todd

    2016-10-01

    The rate of expanded inner speech and speech aloud was compared in 20 typical adults (3 males, 17 females; M age = 24 years, SD = 4). Participants generated and timed spontaneous sentences with both expanded inner speech and speech aloud following the instruction to say "the first thing that comes to mind." The rate of expanded inner speech was slightly, but significantly, faster than the rate of speech aloud. The findings supported the hypothesis that expanded inner speech was faster than speech aloud because of the time required to move the articulators in the latter. Physical measures of speaking rate are needed to validate self-timed measures. Limitations of the study and directions for research are discussed. PMID:27562695

  6. Acid lipase from Candida viswanathii: production, biochemical properties, and potential application.

    PubMed

    de Almeida, Alex Fernando; Tauk-Tornisielo, Sâmia Maria; Carmona, Eleonora Cano

    2013-01-01

    Influences of environmental variables and emulsifiers on lipase production of a Candida viswanathii strain were investigated. The highest lipase activity (101.1 U) was observed at 210 rpm, pH 6.0, and 27.5°C. Other fermentation parameters analyzed showed considerable rates of biomass yield (Y L/S = 1.381 g/g), lipase yield (Y L/S = 6.892 U/g), and biomass productivity (P X = 0.282 g/h). Addition of soybean lecithin increased lipase production in 1.45-fold, presenting lipase yield (Y L/S ) of 10.061 U/g. Crude lipase presented optimal activity at acid pH of 3.5, suggesting a new lipolytic enzyme for this genus and yeast in general. In addition, crude lipase presented high stability in acid conditions and temperature between 40 and 45°C, after 24 h of incubation in these temperatures. Lipase remained active in the presence of organic solvents maintaining above 80% activity in DMSO, methanol, acetonitrile, ethanol, acetone, 1-propanol, isopropanol, and 2-propanol. Effectiveness for the hydrolysis of a wide range of natural triglycerides suggests that this new acid lipase has high potential application in the oleochemical and food industries for hydrolysis and/or modification of triacylglycerols to improve the nutritional properties. PMID:24350270

  7. Acid Lipase from Candida viswanathii: Production, Biochemical Properties, and Potential Application

    PubMed Central

    de Almeida, Alex Fernando; Carmona, Eleonora Cano

    2013-01-01

    Influences of environmental variables and emulsifiers on lipase production of a Candida viswanathii strain were investigated. The highest lipase activity (101.1 U) was observed at 210 rpm, pH 6.0, and 27.5°C. Other fermentation parameters analyzed showed considerable rates of biomass yield (YL/S = 1.381 g/g), lipase yield (YL/S = 6.892 U/g), and biomass productivity (PX = 0.282 g/h). Addition of soybean lecithin increased lipase production in 1.45-fold, presenting lipase yield (YL/S) of 10.061 U/g. Crude lipase presented optimal activity at acid pH of 3.5, suggesting a new lipolytic enzyme for this genus and yeast in general. In addition, crude lipase presented high stability in acid conditions and temperature between 40 and 45°C, after 24 h of incubation in these temperatures. Lipase remained active in the presence of organic solvents maintaining above 80% activity in DMSO, methanol, acetonitrile, ethanol, acetone, 1-propanol, isopropanol, and 2-propanol. Effectiveness for the hydrolysis of a wide range of natural triglycerides suggests that this new acid lipase has high potential application in the oleochemical and food industries for hydrolysis and/or modification of triacylglycerols to improve the nutritional properties. PMID:24350270

  8. 40 CFR 415.280 - Applicability; description of the boric acid production subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CATEGORY Boric Acid Production Subcategory § 415.280 Applicability; description of the boric acid... production of boric acid from ore-mined borax and from borax produced by the Trona process. ... 40 Protection of Environment 29 2011-07-01 2009-07-01 true Applicability; description of the...

  9. 40 CFR 415.280 - Applicability; description of the boric acid production subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CATEGORY Boric Acid Production Subcategory § 415.280 Applicability; description of the boric acid... production of boric acid from ore-mined borax and from borax produced by the Trona process. ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Applicability; description of the...

  10. 40 CFR 415.280 - Applicability; description of the boric acid production subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CATEGORY Boric Acid Production Subcategory § 415.280 Applicability; description of the boric acid... production of boric acid from ore-mined borax and from borax produced by the Trona process. ... 40 Protection of Environment 30 2013-07-01 2012-07-01 true Applicability; description of the...

  11. 40 CFR 415.280 - Applicability; description of the boric acid production subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CATEGORY Boric Acid Production Subcategory § 415.280 Applicability; description of the boric acid... production of boric acid from ore-mined borax and from borax produced by the Trona process. ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Applicability; description of the...

  12. Aspergillus oryzae-based cell factory for direct kojic acid production from cellulose

    PubMed Central

    2014-01-01

    Background Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4-pyrone) is one of the major secondary metabolites in Aspergillus oryzae. It is widely used in food, pharmaceuticals, and cosmetics. The production cost, however, is too high for its use in many applications. Thus, an efficient and cost-effective kojic acid production process would be valuable. However, little is known about the complete set of genes for kojic acid production. Currently, kojic acid is produced from glucose. The efficient production of kojic acid using cellulose as an inexpensive substrate would help establish cost-effective kojic acid production. Results A kojic acid transcription factor gene over-expressing the A. oryzae strain was constructed. Three genes related to kojic acid production in this strain were transcribed in higher amounts than those found in the wild-type strain. This strain produced 26.4 g/L kojic acid from 80 g/L glucose. Furthermore, this strain was transformed with plasmid harboring 3 cellulase genes. The resultant A. oryzae strain successfully produced 0.18 g/L of kojic acid in 6 days of fermentation from the phosphoric acid swollen cellulose. Conclusions Kojic acid was produced directly from cellulose material using genetically engineered A. oryzae. Because A. oryzae has efficient protein secretion ability and secondary metabolite productivity, an A. oryzae-based cell factory could be a platform for the production of various kinds of bio-based chemicals. PMID:24885968

  13. Lactic acid production from xylose by engineered Saccharomyces cerevisiae without PDC or ADH deletion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Production of lactic acid from renewable sugars has received growing attention as lactic acid can be used for making renewable and bio-based plastics. However, most prior studies have focused on production of lactic acid from glucose despite cellulosic hydrolysates contain xylose as well as glucose....

  14. Optimization of ascorbic acid-2-phosphate production from ascorbic acid using resting cell of Brevundimonas diminuta.

    PubMed

    Shin, Woo-Jung; Kim, Byung-Yong; Bang, Won-Gi

    2007-05-01

    With the aim to produce ascorbic acid-2-phosphate (AsA-2-P) from L-ascorbic acid (AsA, Vitamin C), nine bacteria conferring the ability to transform AsA to AsA-2-P were isolated from soil samples alongside known strains from culture collections. Most isolates were classified to the genus Brevundimonas by 16S phylogenetic analysis. Among them, Brevundimonas diminuta KACC 10306 was selected as the experimental strain because of its the highest productivity of AsA-2-P. The optimum set of conditions for the AsA-2-P production from AsA using resting cells as the source of the enzyme was also investigated. The optimum cultivation time was 16 h and the cell concentration was 120 g/l (wet weight). The optimum concentrations of AsA and pyrophosphate were 550 mM and 450 mM, respectively. The most effective buffer was 50 mM sodium formate. The optimum pH was 4.5 and temperature was 40 degrees C. Under the above conditions, 27.5 g/l of AsA-2-P was produced from AsA after 36 h of incubation, which corresponded to a 19.7% conversion efficiency based on the initial concentration of AsA. PMID:18051298

  15. OCCURRENCE OF IODO-ACID AND IODO-THM DISINFECTION BY-PRODUCTS IN DRINKING WATER

    EPA Science Inventory

    As part of a recent Nationwide Disinfection By-product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid, bromoiodoacetic acid, (E)-3-bromo-3-iodo- prope...

  16. OCCURRENCE AND TOXICITY OF IODO-ACID DISINFECTION BY-PRODUCTS IN CHLORAMINATED DRINKING WATER

    EPA Science Inventory

    As part of a recent Nationwide Disinfection By-Product (DBP) Occurrence Study, iodo-acids were identified for the first time as DBPs in drinking water disinfected with chloramines. The iodo-acids identified included iodoacetic acid (IAA), bromoiodoacetic acid, (E)-3-bromo-3-iodo...

  17. Effect of Surfactants on Production of Oxygenated Unsaturated Fatty Acids by Bacillus megaterium ALA2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacillus megaterium ALA2 (NRRL B-21660) produces many oxygenated unsaturated fatty acids from linoleic acid. Its major product, 12,13,17-trihydroxy-9(Z)-octadecenoic acid (12,13,17-THOA), inhibits the growth of some plant pathogenic fungi. Because hydrophobic fatty acids need to be evenly disperse...

  18. Production of levulinic acid and use as a platform chemical for derived products

    SciTech Connect

    Bozell, J.J.; Moens, L.; Elliott, D.C.; Wang, Y.; Neuenscwander, G.G.; Fitzpatrick, S.W.; Bilski, R.J.; Jarnefeld, J.L.

    1999-07-01

    Levulinic acid (LA) can be produced cost effectively and in high yield from renewable feedstocks in a new industrial process. The technology is being demonstrated on a one ton/day scale at a facility in South Glens Falls, New York. Low cost LA can be used as a platform chemical for the production of a wide range of value-added products. This research has demonstrated that LA can be converted to methyltetrahydrofuran (MTHF), a solvent and fuel extender. MTHF is produced in {gt}80% molar yield via a single stage catalytic hydrogenation process. A new preparation of {delta}-aminolevulinic acid (DALA), a broad spectrum herbicide from LA has also been developed. Each step in this new process proceeds in high ({gt}80%) yield and affords DALA (as the hydrochloride salt) in greater than 90% purity, giving a process that could be commercially viable. LA is also being investigated as a starting material for the production of diphenolic acid (DPA), a direct replacement for bisphenol A.

  19. Inhibition of myeloperoxidase-mediated hypochlorous acid production by nitroxides

    PubMed Central

    Rees, Martin D.; Bottle, Steven E.; Fairfull-Smith, Kathryn E.; Malle, Ernst; Whitelock, John M.; Davies, Michael J.

    2014-01-01

    Tissue damage resulting from the extracellular production of HOCl (hypochlorous acid) by the MPO (myeloperoxidase)-hydrogen peroxide-chloride system of activated phagocytes is implicated as a key event in the progression of a number of human inflammatory diseases. Consequently, there is considerable interest in the development of therapeutically useful MPO inhibitors. Nitroxides are well established antioxidant compounds of low toxicity that can attenuate oxidative damage in animal models of inflammatory disease. They are believed to exert protective effects principally by acting as superoxide dismutase mimetics or radical scavengers. However, we show here that nitroxides can also potently inhibit MPO-mediated HOCl production, with the nitroxide 4-aminoTEMPO inhibiting HOCl production by MPO and by neutrophils with IC50 values of approx. 1 and 6 μM respectively. Structure–activity relationships were determined for a range of aliphatic and aromatic nitroxides, and inhibition of oxidative damage to two biologically-important protein targets (albumin and perlecan) are demonstrated. Inhibition was shown to involve one-electron oxidation of the nitroxides by the compound I form of MPO and accumulation of compound II. Haem destruction was also observed with some nitroxides. Inhibition of neutrophil HOCl production by nitroxides was antagonized by neutrophil-derived superoxide, with this attributed to superoxide-mediated reduction of compound II. This effect was marginal with 4-aminoTEMPO, probably due to the efficient superoxide dismutase-mimetic activity of this nitroxide. Overall, these data indicate that nitroxides have considerable promise as therapeutic agents for the inhibition of MPO-mediated damage in inflammatory diseases. PMID:19379130

  20. Plasma arginine and leucine kinetics and urea production rates in burn patients.

    PubMed

    Yu, Y M; Young, V R; Castillo, L; Chapman, T E; Tompkins, R G; Ryan, C M; Burke, J F

    1995-05-01

    We measured plasma arginine and leucine kinetics and rates of urea production (appearance) in 12 severely burned patients (mean body surface burn area, 48%) during a basal state (low-dose intravenous glucose) and while receiving routine, total parenteral nutrition ([TPN] fed state) including an L-amino acid mixture, supplying a generous level of nitrogen (mean, 0.36 g N.kg-1.d-1). The two nutritional states were studied in random order using a primed 4-hour constant intravenous tracer infusion protocol. Stable-nuclide-labeled tracers were L-[guanidino-13C]arginine, L-[1-13C]leucine, [18O]urea, and NaH13CO3 (prime only), with blood and expired air samples drawn at intervals to determine isotopic abundance of arginine, citrulline, ornithine, alpha-ketoisocaproate ([KIC] for leucine), and urea in plasma and 13CO2 in breath. Results are compared with data obtained in these laboratories in healthy adults. Leucine kinetics (flux and disappearance into protein synthesis) indicated the expected higher turnover in burn patients than in healthy controls. Mean leucine oxidation rates are also higher and compared well with values predicted from urea production rates, provided that urea nitrogen recycling via intestinal hydrolysis is taken into account. The plasma urea flux was also higher than for normal subjects. Arginine fluxes as measured in the systemic whole body, via the plasma pool, were correspondingly higher in burned patients than in healthy controls and were in good agreement with values predicted from leucine-KIC kinetics. However, systemic whole-body arginine flux measured via the plasma pool was only 20% of the arginine flux estimated from the urea flux plus the rate of protein synthesis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7752916

  1. Engineering of a glycerol utilization pathway for amino acid production by Corynebacterium glutamicum.

    PubMed

    Rittmann, Doris; Lindner, Steffen N; Wendisch, Volker F

    2008-10-01

    The amino acid-producing organism Corynebacterium glutamicum cannot utilize glycerol, a stoichiometric by-product of biodiesel production. By heterologous expression of Escherichia coli glycerol utilization genes, C. glutamicum was engineered to grow on glycerol. While expression of the E. coli genes for glycerol kinase (glpK) and glycerol 3-phosphate dehydrogenase (glpD) was sufficient for growth on glycerol as the sole carbon and energy source, additional expression of the aquaglyceroporin gene glpF from E. coli increased growth rate and biomass formation. Glutamate production from glycerol was enabled by plasmid-borne expression of E. coli glpF, glpK, and glpD in C. glutamicum wild type. In addition, a lysine-producing C. glutamicum strain expressing E. coli glpF, glpK, and glpD was able to produce lysine from glycerol as the sole carbon substrate as well as from glycerol-glucose mixtures. PMID:18757581

  2. Influence of pH and temperature on alunite dissolution rates and products

    NASA Astrophysics Data System (ADS)

    Acero, Patricia; Hudson-Edwards, Karen

    2015-04-01

    Aluminium is one of the main elements in most mining-affected environments, where it may influence the mobility of other elements and play a key role on pH buffering. Moreover, high concentrations of Al can have severe effects on ecosystems and humans; Al intake, for example, has been implicated in neurological pathologies (e.g., Alzheimer's disease; Flaten, 2001). The behaviour of Al in mining-affected environments is commonly determined, at least partially, by the dissolution of Al sulphate minerals and particularly by the dissolution of alunite (KAl3(SO4)2(OH)6), which is one of the most important and ubiquitous Al sulphates in mining-affected environments (Nordstrom, 2011). The presence of alunite has been described in other acid sulphate environments, including some soils (Prietzel & Hirsch, 1998) and on the surface of Mars (Swayze et al., 2008). Despite the important role of alunite, its dissolution rates and products, and their controlling factors under conditions similar to those found in these environments, remain largely unknown. In this work, batch dissolution experiments have been carried out in order to shed light on the rates, products and controlling factors of alunite dissolution under different pH conditions (between 3 and 8) and temperatures (between 279 and 313K) similar to those encountered in natural systems. The obtained initial dissolution rates using synthetic alunite, based on the evolution of K concentrations, are between 10-9.7 and 10-10.9 mol-m-2-s-1, with the lowest rates obtained at around pH 4.8, and increases in the rates recorded with both increases and decreases in pH. Increases of temperature in the studied range also cause increases in the dissolution rates. The dissolution of alunite dissolution is incongruent, as has been reported for jarosite (isostructural with alunite) by Welch et al. (2008). Compared with the stoichiometric ratio in the bulk alunite (Al/K=3), K tends to be released to the solution preferentially over Al

  3. Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes.

    PubMed

    Ju, Kou-San; Gao, Jiangtao; Doroghazi, James R; Wang, Kwo-Kwang A; Thibodeaux, Christopher J; Li, Steven; Metzger, Emily; Fudala, John; Su, Joleen; Zhang, Jun Kai; Lee, Jaeheon; Cioni, Joel P; Evans, Bradley S; Hirota, Ryuichi; Labeda, David P; van der Donk, Wilfred A; Metcalf, William W

    2015-09-29

    Although natural products have been a particularly rich source of human medicines, activity-based screening results in a very high rate of rediscovery of known molecules. Based on the large number of natural product biosynthetic genes in microbial genomes, many have proposed "genome mining" as an alternative approach for discovery efforts; however, this idea has yet to be performed experimentally on a large scale. Here, we demonstrate the feasibility of large-scale, high-throughput genome mining by screening a collection of over 10,000 actinomycetes for the genetic potential to make phosphonic acids, a class of natural products with diverse and useful bioactivities. Genome sequencing identified a diverse collection of phosphonate biosynthetic gene clusters within 278 strains. These clusters were classified into 64 distinct groups, of which 55 are likely to direct the synthesis of unknown compounds. Characterization of strains within five of these groups resulted in the discovery of a new archetypical pathway for phosphonate biosynthesis, the first (to our knowledge) dedicated pathway for H-phosphinates, and 11 previously undescribed phosphonic acid natural products. Among these compounds are argolaphos, a broad-spectrum antibacterial phosphonopeptide composed of aminomethylphosphonate in peptide linkage to a rare amino acid N(5)-hydroxyarginine; valinophos, an N-acetyl l-Val ester of 2,3-dihydroxypropylphosphonate; and phosphonocystoximate, an unusual thiohydroximate-containing molecule representing a new chemotype of sulfur-containing phosphonate natural products. Analysis of the genome sequences from the remaining strains suggests that the majority of the phosphonate biosynthetic repertoire of Actinobacteria has been captured at the gene level. This dereplicated strain collection now provides a reservoir of numerous, as yet undiscovered, phosphonate natural products. PMID:26324907

  4. Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes

    PubMed Central

    Ju, Kou-San; Gao, Jiangtao; Doroghazi, James R.; Wang, Kwo-Kwang A.; Thibodeaux, Christopher J.; Li, Steven; Metzger, Emily; Fudala, John; Su, Joleen; Zhang, Jun Kai; Lee, Jaeheon; Cioni, Joel P.; Evans, Bradley S.; Hirota, Ryuichi; Labeda, David P.; van der Donk, Wilfred A.; Metcalf, William W.

    2015-01-01

    Although natural products have been a particularly rich source of human medicines, activity-based screening results in a very high rate of rediscovery of known molecules. Based on the large number of natural product biosynthetic genes in microbial genomes, many have proposed “genome mining” as an alternative approach for discovery efforts; however, this idea has yet to be performed experimentally on a large scale. Here, we demonstrate the feasibility of large-scale, high-throughput genome mining by screening a collection of over 10,000 actinomycetes for the genetic potential to make phosphonic acids, a class of natural products with diverse and useful bioactivities. Genome sequencing identified a diverse collection of phosphonate biosynthetic gene clusters within 278 strains. These clusters were classified into 64 distinct groups, of which 55 are likely to direct the synthesis of unknown compounds. Characterization of strains within five of these groups resulted in the discovery of a new archetypical pathway for phosphonate biosynthesis, the first (to our knowledge) dedicated pathway for H-phosphinates, and 11 previously undescribed phosphonic acid natural products. Among these compounds are argolaphos, a broad-spectrum antibacterial phosphonopeptide composed of aminomethylphosphonate in peptide linkage to a rare amino acid N5-hydroxyarginine; valinophos, an N-acetyl l-Val ester of 2,3-dihydroxypropylphosphonate; and phosphonocystoximate, an unusual thiohydroximate-containing molecule representing a new chemotype of sulfur-containing phosphonate natural products. Analysis of the genome sequences from the remaining strains suggests that the majority of the phosphonate biosynthetic repertoire of Actinobacteria has been captured at the gene level. This dereplicated strain collection now provides a reservoir of numerous, as yet undiscovered, phosphonate natural products. PMID:26324907

  5. Interwell Connectivity and Diagnosis Using Correlation of Production and Injection Rate Data in Hydrocarbon Production

    SciTech Connect

    Jerry L. Jensen; Larry W. Lake; Ali Al-Yousef; Dan Weber; Ximing Liang; T.F. Edgar; Nazli Demiroren; Danial Kaviani

    2007-03-31

    This report details progress and results on inferring interwell communication from well rate fluctuations. Starting with the procedure of Albertoni and Lake (2003) as a foundation, the goal of the project was to develop further procedures to infer reservoir properties through weights derived from correlations between injection and production rates. A modified method, described in Yousef and others (2006a,b), and herein referred to as the 'capacitance model', is the primary product of this research project. The capacitance model (CM) produces two quantities, {lambda} and {tau}, for each injector-producer well pair. For the CM, we have focused on the following items: (1) Methods to estimate {lambda} and {tau} from simulated and field well rates. The original method uses both non-linear and linear regression and lacks the ability to include constraints on {lambda} and {tau}. The revised method uses only non-linear regression, permitting constraints to be included as well as accelerating the solution so that problems with large numbers of wells are more tractable. (2) Approaches to integrate {lambda} and {tau} to improve connectivity evaluations. Interpretations have been developed using Lorenz-style and log-log plots to assess heterogeneity. Testing shows the interpretations can identify whether interwell connectivity is controlled by flow through fractures, high-permeability layers, or due to partial completion of wells. Applications to the South Wasson and North Buck Draw Fields show promising results. (3) Optimization of waterflood injection rates using the CM and a power law relationship for watercut to maximize economic return. Tests using simulated data and a range of oil prices show the approach is working. (4) Investigation of methods to increase the robustness of {lambda} and {tau} estimates. Human interventions, such as workovers, also cause rate fluctuations and can be misinterpreted by the model if bottom hole pressure data are not available. A revised

  6. Ferrihydrite dissolution by pyridine-2,6-bis(monothiocarboxylic acid) and hydrolysis products

    NASA Astrophysics Data System (ADS)

    Dhungana, Suraj; Anthony, Charles R.; Hersman, Larry E.

    2007-12-01

    Pyridine-2,6-bis(monothiocarboxylate) (pdtc), a metabolic product of microorganisms, including Pseudomonas putida and Pseudomonas stutzeri was investigated for its ability of dissolve Fe(III)(hydr)oxides at pH 7.5. Concentration dependent dissolution of ferrihydrite under anaerobic environment showed saturation of the dissolution rate at the higher concentration of pdtc. The surface controlled ferrihydrite dissolution rate was determined to be 1.2 × 10 -6 mol m -2 h -1. Anaerobic dissolution of ferrihydrite by pyridine-2,6-dicarboxylic acid or dipicolinic acid (dpa), a hydrolysis product of pdtc, was investigated to study the mechanism(s) involved in the pdtc facilitated ferrihydrite dissolution. These studies suggest that pdtc dissolved ferrihydrite using a reduction step, where dpa chelates the Fe reduced by a second hydrolysis product, H 2S. Dpa facilitated dissolution of ferrihydrite showed very small increase in the Fe dissolution when the concentration of external reductant, ascorbate, was doubled, suggesting the surface dynamics being dominated by the interactions between dpa and ferrihydrite. Greater than stoichiometric amounts of Fe were mobilized during dpa dissolution of ferrihydrite assisted by ascorbate and cysteine. This is attributed to the catalytic dissolution of Fe(III)(hydr)oxides by the in situ generated Fe(II) in the presence of a complex former, dpa.

  7. Inferring Ozone Production in an Urban Atmosphere using Measurements of Peroxynitric Acid

    NASA Technical Reports Server (NTRS)

    Spencer, K. M.; McCabe, D. C.; Crounse, J. D.; Olson, J. R.; Crawford, J. H.; Weinheimer, A. J.; Knapp, D. J.; Montzka, D. D.; Cantrell, C. A.; Anderson, R. S.; Mauldin, R. L.; Wennberg, P. O.

    2009-01-01

    Observations of peroxynitric acid (HO2NO2) obtained simultaneously with those of NO and NO2 provide a sensitive measure of the ozone photochemical production rate. We illustrate this technique for constraining the ozone production rate with observations obtained from the NCAR C-130 aircraft platform during the Megacity Initiative: Local and Global Research Observations (MILAGRO) intensive in Mexico during the spring of 2006. Sensitive and selective measurements of HO2NO2 were made in situ using chemical ionization mass spectrometry (CIMS). Observations were compared to modeled HO2NO2 concentrations obtained from the NASA Langley highly-constrained photochemical time-dependent box model. The median observed-to-calculated ratio of HO2NO2 is 1.18. At NOx levels greater than 15 ppbv, the photochemical box model underpredicts observations with an observed-to-calculated ratio of HO2NO2 of 1.57. As a result, we find that at high NOx, the ozone production rate calculated using measured HO2NO2 is faster than predicted using accepted photochemistry. Inclusion of an additional HOx source from the reaction of excited state NO2 with H2O or reduction in the rate constant of the reaction of OH with NO2 improves the agreement.

  8. r-process Lanthanide Production and Heating Rates in Kilonovae

    NASA Astrophysics Data System (ADS)

    Lippuner, Jonas; Roberts, Luke F.

    2015-12-01

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka & Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Ye, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Ye ≳ 0.22-0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Ye lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Ye, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Ye, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  9. Swfoldrate: predicting protein folding rates from amino acid sequence with sliding window method.

    PubMed

    Cheng, Xiang; Xiao, Xuan; Wu, Zhi-cheng; Wang, Pu; Lin, Wei-zhong

    2013-01-01

    Protein folding is the process by which a protein processes from its denatured state to its specific biologically active conformation. Understanding the relationship between sequences and the folding rates of proteins remains an important challenge. Most previous methods of predicting protein folding rate require the tertiary structure of a protein as an input. In this study, the long-range and short-range contact in protein were used to derive extended version of the pseudo amino acid composition based on sliding window method. This method is capable of predicting the protein folding rates just from the amino acid sequence without the aid of any structural class information. We systematically studied the contributions of individual features to folding rate prediction. The optimal feature selection procedures are adopted by means of combining the forward feature selection and sequential backward selection method. Using the jackknife cross validation test, the method was demonstrated on the large dataset. The predictor was achieved on the basis of multitudinous physicochemical features and statistical features from protein using nonlinear support vector machine (SVM) regression model, the method obtained an excellent agreement between predicted and experimentally observed folding rates of proteins. The correlation coefficient is 0.9313 and the standard error is 2.2692. The prediction server is freely available at http://www.jci-bioinfo.cn/swfrate/input.jsp. PMID:22933332

  10. Quantifying Effect of Lactic, Acetic, and Propionic Acids on Growth of Molds Isolated from Spoiled Bakery Products.

    PubMed

    Dagnas, Stéphane; Gauvry, Emilie; Onno, Bernard; Membré, Jeanne-Marie

    2015-09-01

    The combined effect of undissociated lactic acid (0 to 180 mmol/liter), acetic acid (0 to 60 mmol/liter), and propionic acid (0 to 12 mmol/liter) on growth of the molds Aspergillus niger, Penicillium corylophilum, and Eurotium repens was quantified at pH 3.8 and 25°C on malt extract agar acid medium. The impact of these acids on lag time for growth (λ) was quantified through a gamma model based on the MIC. The impact of these acids on radial growth rate (μ) was analyzed statistically through polynomial regression. Concerning λ, propionic acid exhibited a stronger inhibitory effect (MIC of 8 to 20 mmol/liter depending on the mold species) than did acetic acid (MIC of 23 to 72 mmol/liter). The lactic acid effect was null on E. repens and inhibitory on A. niger and P. corylophilum. These results were validated using independent sets of data for the three acids at pH 3.8 but for only acetic and propionic acids at pH 4.5. Concerning μ, the effect of acetic and propionic acids was slightly inhibitory for A. niger and P. corylophilum but was not significant for E. repens. In contrast, lactic acid promoted radial growth of all three molds. The gamma terms developed here for these acids will be incorporated in a predictive model for temperature, water activity, and acid. More generally, results for μ and λ will be used to identify and evaluate solutions for controlling bakery product spoilage. PMID:26319723

  11. 30 CFR 250.1159 - May the Regional Supervisor limit my well or reservoir production rates?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Supervisor limit my well or reservoir production rates? (a) The Regional Supervisor may set a Maximum Production Rate (MPR) for a producing well completion, or set a Maximum Efficient Rate (MER) for a reservoir... 30 Mineral Resources 2 2011-07-01 2011-07-01 false May the Regional Supervisor limit my well...

  12. 39 CFR 3.9 - Establishment of rates and classes of competitive products of general applicability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Establishment of rates and classes of competitive... classes of competitive products of general applicability. This section relates to changes in rates or classes of competitive products of general applicability. (a) Prior to establishing changes in rates...

  13. 39 CFR 3.9 - Establishment of rates and classes of competitive products of general applicability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Establishment of rates and classes of competitive... classes of competitive products of general applicability. This section relates to changes in rates or classes of competitive products of general applicability. (a) Prior to establishing changes in rates...

  14. 39 CFR 3.9 - Establishment of rates and classes of competitive products of general applicability.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Establishment of rates and classes of competitive... classes of competitive products of general applicability. This section relates to changes in rates or classes of competitive products of general applicability. (a) Prior to establishing changes in rates...

  15. 39 CFR 3.9 - Establishment of rates and classes of competitive products of general applicability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Establishment of rates and classes of competitive... classes of competitive products of general applicability. This section relates to changes in rates or classes of competitive products of general applicability. (a) Prior to establishing changes in rates...

  16. 39 CFR 3.9 - Establishment of rates and classes of competitive products of general applicability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Establishment of rates and classes of competitive... classes of competitive products of general applicability. This section relates to changes in rates or classes of competitive products of general applicability. (a) Prior to establishing changes in rates...

  17. 75 FR 47650 - International Product Change-Global Expedited Package Services-Non-Published Rates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-06

    ... Product Change--Global Expedited Package Services-- Non-Published Rates AGENCY: Postal Service\\TM\\ ACTION... Commission to add Global Expedited Package Services Contracts--Non-Published Rates to the Competitive... Service to add Global Expedited Package Contracts--Non-Published Rates to the Competitive Products...

  18. Effect of dietary fatty acids on metabolic rate and nonshivering thermogenesis in golden hamsters.

    PubMed

    Jefimow, Małgorzata; Wojciechowski, Michał S

    2014-02-01

    Hibernating rodents prior to winter tend to select food rich in polyunsaturated fatty acids (PUFA). Several studies found that such diet may positively affect their winter energy budget by enhancing torpor episodes. However, the effect of composition of dietary fatty acids (FA) on metabolism of normothermic heterotherms is poorly understood. Thus we tested whether diets different in FA composition affect metabolic rate (MR) and the capacity for nonshivering thermogenesis (NST) in normothermic golden hamsters (Mesocricetus auratus). Animals were housed in outdoor enclosures from May 2010 to April 2011 and fed a diet enriched with PUFA (i.e., standard food supplemented weekly with sunflower and flax seeds) or with saturated and monounsaturated fatty acids (SFA/MUFA, standard food supplemented with mealworms). Since diet rich in PUFA results in lower MR in hibernating animals, we predicted that PUFA-rich diet would have similar effect on MR of normothermic hamsters, that is, normothermic hamsters on the PUFA diet would have lower metabolic rate in cold and higher NST capacity than hamsters supplemented with SFA/MUFA. Indeed, in winter resting metabolic rate (RMR) below the lower critical temperature was higher and NST capacity was lower in SFA/MUFA-supplemented animals than in PUFA-supplemented ones. These results suggest that the increased capacity for NST in PUFA-supplemented hamsters enables them lower RMR below the lower critical temperature of the thermoneural zone. PMID:24151228

  19. A Simple Demonstration of Carbon Dioxide Fixation and Acid Production in CAM Plants

    ERIC Educational Resources Information Center

    Walker, John R. L.; McWha, James A.

    1976-01-01

    Described is an experiment investigating carbon dioxide fixation in the dark and the diurnal rhythm of acid production in plants exhibiting Crassulacean Acid Metabolism. Included are suggestions for four further investigations. (SL)

  20. Development of a stepwise aeration control strategy for efficient docosahexaenoic acid production by Schizochytrium sp.

    PubMed

    Ren, Lu-Jing; Ji, Xiao-Jun; Huang, He; Qu, Liang; Feng, Yun; Tong, Qian-Qian; Ouyang, Ping-Kai

    2010-08-01

    The effect of aeration on the performance of docosahexaenoic acid (DHA) production by Schizochytrium sp. was investigated in a 1,500-L bioreactor using fed-batch fermentation. Six parameters, including specific growth rate, specific glucose consumption rate, specific lipid accumulation rate, cell yield coefficient, lipid yield coefficient, and DHA yield coefficient, were used to understand the relationship between aeration and the fermentation characteristics. Based on the information obtained from the parameters, a stepwise aeration control strategy was proposed. The aeration rate was controlled at 0.4 volume of air per volume of liquid per minute (vvm) for the first 24 h, then shifted to 0.6 vvm until 96 h, and then switched back to 0.4 vvm until the end of the fermentation. High cell density (71 g/L), high lipid content (35.75 g/L), and high DHA percentage (48.95%) were achieved by using this strategy, and DHA productivity reached 119 mg/L h, which was 11.21% over the best results obtained by constant aeration rate. PMID:20445973

  1. Production of citric and oxalic acids and solubilization of calcium phosphate by Penicillium bilaii.

    PubMed Central

    Cunningham, J E; Kuiack, C

    1992-01-01

    An isolate of Penicillium bilaii previously reported to solubilize mineral phosphates and enhance plant uptake of phosphate was studied. Using agar media with calcium phosphate and the pH indicator alizarin red S, the influence of the medium composition on phosphate solubility and medium acidification was recorded. The major acidic metabolites produced by P. bilaii in a sucrose nitrate liquid medium were found to be oxalic acid and citric acid. Citric acid production was promoted under nitrogen-limited conditions, while oxalic acid production was promoted under carbon-limited conditions. Citric acid was produced in both growth and stationary phases, but oxalic acid production occurred only in stationary phase. When submerged cultures which normally produce acid were induced to sporulate, the culture medium shifted toward alkaline rather than acid reaction with growth. PMID:1622211

  2. Variable-Rate Lime Application for Louisiana Sugarcane Production Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precision agriculture may offer sugarcane growers a management system that decreases costs and maximizes profits, while minimizing any potential negative environmental impact. Variable rate (VR) application of lime and fertilizers is one area in which significant advantages may be realized. A seri...

  3. Nitrogen rates for biomass sorghum production across tillage systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biomass yields and nutrient removal across different tillage systems and nitrogen rates are not well established for forage sorghum (Sorghum bicolor L. Moench) grown as an energy source in the Southeast. An experiment was initiated in long-term conventional and conservation tillage systems on a Comp...

  4. Camelina production affected by seeding rate and depth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Camelina (Camelina sativa L.) is an oilseed that has shown potential as an alternative crop to diversify wheat-fallow systems in the northern Great Plains. However, agronomic information is lacking for management of this relatively new crop. The impact of seeding depth and rate were determined in s...

  5. Degradation of Fructans and Production of Propionic Acid by Bacteroides thetaiotaomicron are Enhanced by the Shortage of Amino Acids.

    PubMed

    Adamberg, Signe; Tomson, Katrin; Vija, Heiki; Puurand, Marju; Kabanova, Natalja; Visnapuu, Triinu; Jõgi, Eerik; Alamäe, Tiina; Adamberg, Kaarel

    2014-01-01

    Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory) and levan (synthesized using levansucrase from Pseudomonas syringae), two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (degree of polymerization > 3). Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h), followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of d-lactate (82 ± 33 mmol/gDW) occurred in parallel with extensive consumption (up to 17 mmol/gDW) of amino acids, especially Ser, Thr, and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will

  6. Degradation of Fructans and Production of Propionic Acid by Bacteroides thetaiotaomicron are Enhanced by the Shortage of Amino Acids

    PubMed Central

    Adamberg, Signe; Tomson, Katrin; Vija, Heiki; Puurand, Marju; Kabanova, Natalja; Visnapuu, Triinu; Jõgi, Eerik; Alamäe, Tiina; Adamberg, Kaarel

    2014-01-01

    Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory) and levan (synthesized using levansucrase from Pseudomonas syringae), two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (degree of polymerization > 3). Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h), followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of d-lactate (82 ± 33 mmol/gDW) occurred in parallel with extensive consumption (up to 17 mmol/gDW) of amino acids, especially Ser, Thr, and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will

  7. Sidedress nitrogen rates and costs for Southeastern cotton production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) is typically the most important fertilizer input for cotton (Gossypium hirsutum L.), and usually ranks in the top five production expenses for cotton. Previous N recommendations have been based on conventional tillage practices that do not include cover crops. Our objective was to det...

  8. High biomass sorghum production across tillage systems and nitrogen rates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioenergy production has traditionally focused on perennial crops; however, these crops require an establishment period before they can be utilized. High biomass sorghum (Sorghum bicolor L. Moench) grown as an annual crop can be used during this establishment period, but typical yields and nutrient...

  9. FORMATION OF ACIDIC TRACE ORGANIC BY-PRODUCTS FROM THE CHLORINATION OF HUMIC ACIDS

    EPA Science Inventory

    A method for concentrating and analyzing acidic trace organics produced by the chlorination of humic acids at concentrations approximating common drinking water levels is described. Data are compared from several humic acid sources. Specific compound analyses of the extracts were...

  10. Probabilistic exposure assessment model to estimate aseptic-UHT product failure rate.

    PubMed

    Pujol, Laure; Albert, Isabelle; Magras, Catherine; Johnson, Nicholas Brian; Membré, Jeanne-Marie

    2015-01-01

    Aseptic-Ultra-High-Temperature (UHT) products are manufactured to be free of microorganisms capable of growing in the food at normal non-refrigerated conditions at which the food is likely to be held during manufacture, distribution and storage. Two important phases within the process are widely recognised as critical in controlling microbial contamination: the sterilisation steps and the following aseptic steps. Of the microbial hazards, the pathogen spore formers Clostridium botulinum and Bacillus cereus are deemed the most pertinent to be controlled. In addition, due to a relatively high thermal resistance, Geobacillus stearothermophilus spores are considered a concern for spoilage of low acid aseptic-UHT products. A probabilistic exposure assessment model has been developed in order to assess the aseptic-UHT product failure rate associated with these three bacteria. It was a Modular Process Risk Model, based on nine modules. They described: i) the microbial contamination introduced by the raw materials, either from the product (i.e. milk, cocoa and dextrose powders and water) or the packaging (i.e. bottle and sealing component), ii) the sterilisation processes, of either the product or the packaging material, iii) the possible recontamination during subsequent processing of both product and packaging. The Sterility Failure Rate (SFR) was defined as the sum of bottles contaminated for each batch, divided by the total number of bottles produced per process line run (10(6) batches simulated per process line). The SFR associated with the three bacteria was estimated at the last step of the process (i.e. after Module 9) but also after each module, allowing for the identification of modules, and responsible contamination pathways, with higher or lower intermediate SFR. The model contained 42 controlled settings associated with factory environment, process line or product formulation, and more than 55 probabilistic inputs corresponding to inputs with variability

  11. Wastes from bioethanol and beer productions as substrates for l(+) lactic acid production - A comparative study.

    PubMed

    Djukić-Vuković, Aleksandra; Mladenović, Dragana; Radosavljević, Miloš; Kocić-Tanackov, Sunčica; Pejin, Jelena; Mojović, Ljiljana

    2016-02-01

    Waste substrates from bioethanol and beer productions are cheap, abundant and renewable substrates for biorefinery production of lactic acid (LA) and variability in their chemical composition presents a challenge in their valorisation. Three types of waste substrates, wasted bread and wasted potato stillage from bioethanol production and brewers' spent grain hydrolysate from beer production were studied as substrates for the production of l(+) LA and probiotic biomass by Lactobacillus rhamnosus ATCC 7469. The correlation of the content of free alpha amino nitrogen and the production of LA was determined as a critical characteristic of the waste media for efficient LA production by L. rhamnosus on the substrates which contained equal amount of fermentable sugars. A maximal LA productivity of 1.54gL(-1)h(-1) was obtained on wasted bread stillage media, whilst maximal productivities achieved on the potato stillage and brewers' spent grain hydrolysate media were 1.28gL(-1)h(-1)and 0.48gL(-1)h(-1), respectively. A highest LA yield of 0.91gg(-1) was achieved on wasted bread stillage media, followed by the yield of 0.81gg(-1) on wasted potato stillage and 0.34gg(-1) on brewers' spent grain hydrolysate media. The kinetics of sugar consumption in the two stillage substrates were similar while the sugar conversion in brewers' spent grain hydrolysate was slower and less efficient due to significantly lower content of free alpha amino nitrogen. The lignocellulosic hydrolysate from beer production required additional supplementation with nitrogen. PMID:26639411

  12. SAVANNAH RIVER SITE TANK CLEANING: CORROSION RATE FOR ONE VERSUS EIGHT PERCENT OXALIC ACID SOLUTION

    SciTech Connect

    Ketusky, E.; Subramanian, K.

    2011-01-20

    Until recently, the use of oxalic acid for chemically cleaning the Savannah River Site (SRS) radioactive waste tanks focused on using concentrated 4 and 8-wt% solutions. Recent testing and research on applicable dissolution mechanisms have concluded that under appropriate conditions, dilute solutions of oxalic acid (i.e., 1-wt%) may be more effective. Based on the need to maximize cleaning effectiveness, coupled with the need to minimize downstream impacts, SRS is now developing plans for using a 1-wt% oxalic acid solution. A technology gap associated with using a 1-wt% oxalic acid solution was a dearth of suitable corrosion data. Assuming oxalic acid's passivation of carbon steel was proportional to the free oxalate concentration, the general corrosion rate (CR) from a 1-wt% solution may not be bound by those from 8-wt%. Therefore, after developing the test strategy and plan, the corrosion testing was performed. Starting with the envisioned process specific baseline solvent, a 1-wt% oxalic acid solution, with sludge (limited to Purex type sludge-simulant for this initial effort) at 75 C and agitated, the corrosion rate (CR) was determined from the measured weight loss of the exposed coupon. Environmental variations tested were: (a) Inclusion of sludge in the test vessel or assuming a pure oxalic acid solution; (b) acid solution temperature maintained at 75 or 45 C; and (c) agitation of the acid solution or stagnant. Application of select electrochemical testing (EC) explored the impact of each variation on the passivation mechanisms and confirmed the CR. The 1-wt% results were then compared to those from the 8-wt%. The immersion coupons showed that the maximum time averaged CR for a 1-wt% solution with sludge was less than 25-mils/yr for all conditions. For an agitated 8-wt% solution with sludge, the maximum time averaged CR was about 30-mils/yr at 50 C, and 86-mils/yr at 75 C. Both the 1-wt% and the 8-wt% testing demonstrated that if the sludge was removed from

  13. Fermentative production of shikimic acid: a paradigm shift of production concept from plant route to microbial route.

    PubMed

    Tripathi, Priyanka; Rawat, Garima; Yadav, Sweta; Saxena, R K

    2013-11-01

    Different physiological and nutritional parameters affect the fermentative production of shikimic acid. In our study, Citrobacter freundii initially produced 0.62 g/L of shikimic acid in 72 h. However, when process optimization was employed, 5.11 g/L of shikimic acid was produced in the production medium consisting of glucose (5.0 %), asparagine (4.5 %), CaCO3 (2.0 %), at pH 6.0, when inoculated with 6 % inoculum and incubated at 30 ± 1 °C, 200 rpm for 60 h. Preliminary fed-batch studies have resulted in the production of 9.11 g/L of shikimic acid on feeding the production medium by 20 g/L of glucose at 24 h of the fermentation run. Production of similar amount of shikimic acid was observed when the optimized conditions were employed in a 10-L bioreactor as obtained in shake flask conditions. A total of 9.11 g/L of shikimic acid was produced in 60 h. This is approximately 14.69-fold increase in shikimic acid production when compared to the initial un-optimized production conditions. This has also resulted in the reduction of the production time. The present study provides useful information to the industrialists seeking environmentally benign technology for the production of bulk biomolecules through manipulation of various chemical parameters. PMID:23543261

  14. Ionic Strength Effect on the Rate of Reduction of Hexacyanoferrate(III) by Ascorbic Acid: A Flow Injection Kinetic Experiment

    NASA Astrophysics Data System (ADS)

    Nobrega, Joanquim A.; Rocha, Fabio R. P.

    1997-05-01

    Flow injection analysis (FIA) is a well recognized tool for solutions management. In spite of the use of this technique mainly for quantitative determination of analytes in solution, FIA systems can also be used for obtaining physical chemistry data. This work describes the use of a flow diagram to perform a kinetic experiment: the effect of ionic strength on the rate of reduction of hexacyanoferrate(III) by ascorbic acid. The rate determining step of this reaction involves the collision between two anionic species. The increase of the ionic strength of the medium alters the ionic atmosphere and changes the charge densities around the anions. Consequently, there is an increment of the rate constants for higher ionic strengths. In the proposed system, the flow is stopped by commutation when the center of the sample zone attained the flow cell and a gradual decrease in signal, related to the redox reaction, is registered as function of time. This allowed the determination of the rate constants as a function of the ionic strength. The product of the charges of the ions involved in the rate determining step was estimated in 3.2 that is close to the expected value considering the proposed mechanism.

  15. Production of 14-oxo-cis-11-eicosenoic acid from lesquerolic acid by genetically variable Sphingobacterium multivorum strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to explore the extent of microbial conversion of lesquerolic acid (LQA; 14-hydroxy-cis-11-eicosenoic acid) by whole cell catalysis and to identify the newly converted product. Among 17 environmental isolates selected from compost amended with soybean oil and unsatura...

  16. Increased Production of Fatty Acids and Triglycerides in Aspergillus oryzae by Enhancing Expressions of Fatty Acid Synthesis-Related Genes

    SciTech Connect

    Tamano, Koichi; Bruno, Kenneth S.; Karagiosis, Sue A.; Culley, David E.; Deng, Shuang; Collett, James R.; Umemura, Myco; Koike, Hideaki; Baker, Scott E.; Machida, Masa

    2013-01-01

    Microbial production of fats and oils is being developedas a means of converting biomass to biofuels. Here we investigate enhancing expression of enzymes involved in the production of fatty acids and triglycerides as a means to increase production of these compounds in Aspergillusoryzae. Examination of the A.oryzaegenome demonstrates that it contains twofatty acid synthases and several other genes that are predicted to be part of this biosynthetic pathway. We enhancedthe expressionof fatty acid synthesis-related genes by replacing their promoters with thepromoter fromthe constitutively highly expressedgene tef1. We demonstrate that by simply increasing the expression of the fatty acid synthasegenes we successfullyincreasedtheproduction of fatty acids and triglyceridesby more than two fold. Enhancement of expression of the fatty acid pathway genes ATP-citrate lyase and palmitoyl-ACP thioesteraseincreasedproductivity to a lesser extent.Increasing expression ofacetyl-CoA carboxylase caused no detectable change in fatty acid levels. Increases in message level for each gene were monitored usingquantitative real-time RT-PCR. Our data demonstrates that a simple increase in the abundance of fatty acid synthase genes can increase the detectable amount of fatty acids.

  17. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED... fermentation product. Condensed, extracted glutamic acid fermentation product may be safely used in animal feed... glutamic acid. (b) It is used or intended for use as follows: (1) In poultry feed as a source of protein...

  18. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED... fermentation product. Condensed, extracted glutamic acid fermentation product may be safely used in animal feed... glutamic acid. (b) It is used or intended for use as follows: (1) In poultry feed as a source of protein...

  19. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED... fermentation product. Condensed, extracted glutamic acid fermentation product may be safely used in animal feed... glutamic acid. (b) It is used or intended for use as follows: (1) In poultry feed as a source of protein...

  20. 21 CFR 573.500 - Condensed, extracted glutamic acid fermentation product.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED... fermentation product. Condensed, extracted glutamic acid fermentation product may be safely used in animal feed... glutamic acid. (b) It is used or intended for use as follows: (1) In poultry feed as a source of protein...

  1. Massive production of farnesol-derived dicarboxylic acids in mice treated with the squalene synthase inhibitor zaragozic acid A.

    PubMed

    Vaidya, S; Bostedor, R; Kurtz, M M; Bergstrom, J D; Bansal, V S

    1998-07-01

    The zaragozic acids are potent inhibitors of squalene synthase. In vivo studies in mice confirmed our earlier observations that inhibition of squalene synthase by zaragozic acid A was accompanied by an increase in the incorporation of label from [3H]mevalonate into farnesyl-diphosphate (FPP)-derived isoprenoic acids (J. D. Bergstrom et al., 1993, Proc. Natl. Acad. Sci. USA 90, 80-84). Farnesyl-diphosphate-derived metabolites appear transiently in the liver. We were unable to detect any farnesol formation in the zaragozic acid-treated animals which indicates that FPP is readily converted to farnesoic acid and dicarboxylic acids in the liver. These metabolites were found to be produced only in the liver and not in the kidney. trans-3,7-Dimethyl-2-octaen-1,8-dioic acid and 3, 7-dimethyloctan-1,8-dioic acid were identified as the major end products of farnesyl-diphosphate metabolism in the urine of mice treated with zaragozic acid A. Quantitative analysis of these FPP-derived dicarboxylic acids by gas-liquid chromatography revealed that approximately 11 mg of total dicarboxylic acids is excreted per day into the urine of a mouse after 3 days of treatment with zaragozic acid A. PMID:9647670

  2. Water Relations, Diurnal Acidity Changes, and Productivity of a Cultivated Cactus, Opuntia ficus-indica1

    PubMed Central

    Acevedo, Edmundo; Badilla, Ignacio; Nobel, Park S.

    1983-01-01

    Physiological responses of the Crassulacean acid metabolism (CAM) plant Opuntia ficus-indica (Cactaceae) were studied on a commercial plantation in central Chile. Young cladodes (flattened stems) and flower buds exhibited daytime stomatal opening, whereas mature cladodes and fruit exhibited the nocturnal stomatal opening characteristic of CAM plants. Severe water stress suppressed the nocturnal stomatal opening by mature cladodes, but their high water vapor conductance occurring near dawn was not affected. Nocturnal acidity increases were not as sensitive to water stress as was the nocturnal stomatal opening. The magnitude of the nocturnal acidity increases depended on the total daily photosynthetically active radiation (PAR), being 90% PAR-saturated at 27 moles per square meter per day for a mean nighttime air temperature of 5°C and at 20 moles per square meter per day for 18°C. Inasmuch as the PAR received on unshaded vertical surfaces averaged about 21 moles per square meter per day, nocturnal acidity increases by the cladodes were on the verge of being PAR-limited in the field. The net assimilation rate, which was positive throughout the year, annually averaged 3.4 grams per square meter per day for 1.0- and 2.0-year-old plants. Plants that were 5.4 years old had 7.2 square meters of cladode surface area (both sides) and an annual dry weight productivity of 13 megagrams (metric tons) per hectare per year when their ground cover was 32%. This substantial productivity for a CAM plant was accompanied by the highest nocturnal acidity increase so far observed in the field, 0.78 mole H+ per square meter. PMID:16663084

  3. Reactivity of chlorine radical with submicron palmitic acid particles: kinetic measurements and products identification

    NASA Astrophysics Data System (ADS)

    Mendez, M.; Ciuraru, R.; Gosselin, S.; Batut, S.; Visez, N.; Petitprez, D.

    2013-06-01

    The heterogeneous reaction of Cl. radicals with sub-micron palmitic acid (PA) particles was studied in an aerosol flow tube in the presence or in the absence of O2. Fine particles were generated by homogeneous condensation of PA vapors and introduced in the reactor where chlorine atoms are produced by photolysis of Cl2 using UV lamps surrounding the reactor. The effective reactive uptake coefficient (γ) has been determined from the rate loss of PA measured by GC/MS analysis of reacted particles as a function of the chlorine exposure. In the absence of O2, γ = 14 ± 5 indicates efficient secondary chemistry involving Cl2. GC/MS analyses have shown the formation of monochlorinated and polychlorinated compounds in the oxidized particles. Although, the PA particles are solid, the complete mass can be consumed. In the presence of oxygen, the reaction is still dominated by secondary chemistry but the propagation chain length is smaller than in the absence of O2 which leads to an uptake coefficient γ = 3 ± 1. In the particulate phase, oxocarboxylic acids and dicarboxylic acids are identified by GC/MS. Formation of alcohols and monocarboxylic acids are also suspected. All these results show that solid organic particles could be efficiently oxidized by gas-phase radicals not only on their surface, but also in bulk by mechanisms which are still unclear. Furthermore the identified reaction products are explained by a chemical mechanism showing the pathway of the formation of more functionalized products. They help to understand the aging of primary tropospheric aerosol containing fatty acids.

  4. Effects of culture (China vs. US) and task on perceived hazard: Evidence from product ratings, label ratings, and product to label matching.

    PubMed

    Lesch, Mary F; Rau, Pei-Luen Patrick; Choi, YoonSun

    2016-01-01

    In the current study, 44 Chinese and 40 US college students rated their perceived hazard in response to warning labels and products and attempted to match products with warning labels communicating the same level of hazard. Chinese participants tended to provide lower ratings of hazard in response to labels, but hazard perceived in response to products did not significantly differ as a function of culture. When asked to match a product with a warning label, Chinese participants' hazard perceptions appeared to be better calibrated, than did US participants', across products and labels. The results are interpreted in terms of constructivist theory which suggests that risk perceptions vary depending on the "frame of mind" evoked by the environment/context. Designers of warnings must be sensitive to the fact that product users' cognitive representations develop within a culture and that risk perceptions will vary based on the context in which they are derived. PMID:26360193

  5. The role of methanogens in acetic acid production under different salinity conditions.

    PubMed

    Xiao, Keke; Guo, Chenghong; Maspolim, Yogananda; Zhou, Yan; Ng, Wun Jern

    2016-10-01

    In this study, a fed-batch acidogenic reactor was operated at a 3 d hydraulic retention time (HRT) and fed with alkaline pre-treated sludge to investigate salinity effects on methanogens' abundance, activities and their consumption of produced acetic acid (HAc) and total volatile fatty acids (VFAs). The salinity concentration was increased step-wise by adding sodium chloride. At 3‰ (parts per thousand) salinity, the average produced volatile fatty acids (VFAs) concentration was 2410.16 ± 637.62 mg COD L(-1) and 2.70 ± 0.36 L methane was produced daily in the acidogenic reactor. Further batch tests indicated methanogens showed a HAc degradation rate of 3.81 mg COD g(-1) VSS h(-1) at initial HAc concentration of 1150 mg COD L(-1), and showed tolerance up to 16‰ salinity (3.76 g Na(+) L(-1)) as indicated by a constant HAc degradation rate. The microbiological study indicated this can be related to the predominance of acetate-utilizing Methanosarcinaceae and Methanomicrobiales in the reactor. However, with salinity increased to 20‰ and 40‰, increases in VFAs and HAc production and decreases in methane production, methanogens population, acidogenic bacteria population and acidification extent were observed. This study demonstrated presence of acetate-utilizing methanogens in an acidogenic reactor and their high tolerance to salinity, as well as their negative impacts on net VFAs production. The results would suggest the presence of methanogens in the acidogenic reactor should not be ignored and the recovery of methane from the acidogenic reactor needs to be considered to avoid carbon loss. PMID:27421101

  6. Production of hydroxylated fatty acids in genetically modified plants

    DOEpatents

    Somerville, Chris; Broun, Pierre; van de Loo, Frank; Boddupalli, Sekhar S.

    2005-08-30

    This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

  7. Production of hydroxylated fatty acids in genetically modified plants

    DOEpatents

    Somerville, Chris; Broun, Pierre; van de Loo, Frank; Boddupalli, Sekhar S.

    2011-08-23

    This invention relates to plant fatty acyl hydroxylases. Methods to use conserved amino acid or nucleotide sequences to obtain plant fatty acyl hydroxylases are described. Also described is the use of cDNA clones encoding a plant hydroxylase to produce a family of hydroxylated fatty acids in transgenic plants. In addition, the use of genes encoding fatty acid hydroxylases or desaturases to alter the level of lipid fatty acid unsaturation in transgenic plants is described.

  8. Mammalian Cell Cytotoxicity and Genotoxicity of the Haloacetic Acids, A Major Class of Drinking Water Disinfection By-Products

    EPA Science Inventory

    The haloacetic acids (HAAs) are disinfection by-products (DBPs) that are formed during the disinfection of drinking water, wastewaters and recreational pool waters. Currently, five HAAs [bromoacetic acid (BAA), dibromoacetic acid (DBAA), chloroacetic acid (CAA), dichloroacetic ac...

  9. Bioflocculant production by Haloplanus vescus and its application in acid brilliant scarlet yellow/red removal.

    PubMed

    Zhong, Chun-Ying; Chen, Hong-Gao; Cao, Gang; Wang, Jun; Zhou, Jian-Gang

    2016-01-01

    A novel bioflocculant MBF057 produced by a salt-tolerant Haloplanus vescus HW0579 was investigated in this study. The effects of culture conditions such as initial pH, inoculum size, and chemical oxygen demand (COD) of K-acid wastewater on MBF0579 production were studied. The result showed that 8.09 g/L purified MBF0579 was extracted with the following optimized conditions: 780 mg/L COD of K-acid wastewater as carbon source, inoculum size 12.5%, and initial pH 7.0. The biopolymer contained 78.6% polysaccharides and 21.1% proteins. The highest flocculating rate of 81.86 and 95.07% for the COD and chroma of acid brilliant scarlet gelb rot (yellow/red, GR) dye wastewater were achieved at a dosage of 150 mg/L, pH 2.0 and contact time 100 min. Overall, these findings indicate bioflocculation offers an effective alternative method of decreasing acid brilliant scarlet GR during dye wastewater treatment. PMID:26901711

  10. Bioconverted Products of Essential Fatty Acids as Potential Antimicrobial Agents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review deals with the recent findings on the microbial conversion of essential fatty acids (EFAs) through Pseudomonas aeruginosa PR3 NRRL-B-18602, and the antimicrobial properties of bioconverted essential fatty acids, with particular emphasis on n-3 or n-6 fatty acids. The first section deals...

  11. Production of Lipase and Oxygenated Fatty Acids from Vegetable Oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetable oils such as soybean oil and corn oil are cheap raw materials. Various value-added oxygenated fatty acids have been produced from unsaturated fatty acids such as oleic and linoleic acid by biotransformation. Lipase from the non-pathogenic yeast Candida cylindracea is another important va...

  12. Production of methyl-vinyl ketone from levulinic acid

    DOEpatents

    Dumesic, James A.; West; Ryan M.

    2011-06-14

    A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.

  13. Interwell Connectivity and Diagnosis Using Correlation of Production and Injection Rate Data in Hydrocarbon Production

    SciTech Connect

    Jerry L. Jensen; Larry W. Lake; Ali Al-Yousef; Pablo Gentil; Nazli Demiroren

    2005-05-31

    This report details progress on inferring interwell communication from well rate fluctuations. Starting with the procedure of Albertoni and Lake (2003) as a foundation, the goal of the project is to develop further procedures to infer reservoir properties through weights derived from correlations between injection and production rates. A modified method, described in Jensen et al. (2005) and Yousef et al. (2005), and herein referred to as the ''capacitance model'', produces two quantities, {lambda} and {tau}, for each injector-producer well pair. We have focused on the following items: (1) Approaches to integrate {lambda} and {tau} to improve connectivity evaluations. Interpretations have been developed using Lorenz-style and log-log plots to assess heterogeneity. Testing shows the interpretations can identify whether interwell connectivity is controlled by flow through fractures, high-permeability layers, or due to partial completion of wells. Applications to the South Wasson and North Buck Draw Fields show promising results. (2) Optimization of waterflood injection rates using the capacitance model and a power law relationship for watercut to maximize economic return. Initial tests using simulated data and a range of oil prices show the approach is working. (3) Spectral analysis of injection and production data to estimate interwell connectivity and to assess the effects of near-wellbore gas on the results. Development of methods and analysis are ongoing. (4) Investigation of methods to increase the robustness of the capacitance method. These methods include revising the solution method to simultaneously estimate {lambda} and {tau} for each well pair. This approach allows for further constraints to be imposed during the computation, such as limiting {tau} to a range of values defined by the sampling interval and duration of the field data. This work is proceeding. Further work on this project includes the following: (1) Refinement and testing of the waterflood

  14. Tauroursodeoxycholic acid improves the implantation and live-birth rates of mouse embryos.

    PubMed

    Lin, Tao; Diao, Yun Fei; Kang, Jung Won; Lee, Jae Eun; Kim, Dong Kyu; Jin, Dong Il

    2015-06-01

    We previously demonstrated that tauroursodeoxycholic acid (TUDCA) improved the developmental competence of mouse embryos by attenuating endoplasmic reticulum (ER) stress-induced apoptosis during preimplantation development. Here, we present a follow-up study examining whether TUDCA enhances the implantation and live-birth rate of mouse embryos. Mouse 2-cell embryos were collected by oviduct flushing and cultured in the presence or absence of 50 μM TUDCA. After culture (52 h), blastocysts were transferred to 2.5-day pseudopregnant foster mothers. It was found that the rates of pregnancy and implantation as well as the number of live pups per surrogate mouse were significantly higher in the TUDCA-treated group compared to the control group, but there was no significant difference in the mean weights of the pups or placentae. Thus, we report for the first time that TUDCA supplementation of the embryo culture medium increased the implantation and livebirth rates of transferred mouse embryos. PMID:26051458

  15. PHOSPHATED, ACID-ETCHED IMPLANTS DECREASE MINERAL APPOSITION RATES NEAR IMPLANTS IN CANINES

    PubMed Central

    Foley, Christine Hyon; Kerns, David G.; Hallmon, William W.; Rivera-Hidalgo, Francisco; Nelson, Carl J.; Spears, Robert; Dechow, Paul C.; Opperman, Lynne A.

    2010-01-01

    Purpose: This study evaluated the effects of phosphate-coated titanium on mineral apposition rate (MAR) and new bone-to-implant contact (BIC) in canines. Materials and Methods: 2.2 mm × 4 mm electrolytically phosphated or non-phosphated titanium implants with acid-etched surfaces were placed in 48 mandibular sites in 6 foxhounds. Tetracycline and calcein dyes were administered 1 week after implant placement and 1 week before sacrifice. At twelve weeks following implant healing, animals were sacrificed. MAR and BIC were evaluated using fluorescence microscopy. Light microscopic and histological evaluation was performed on undecalcified sections. Results: Microscopic evaluation showed the presence of healthy osteoblasts lining bone surfaces near implants. Similar bone-to-implant contact was observed in phosphated and non-phosphated titanium implant sites. MAR was significantly higher near non-phosphated titanium implant surfaces than the phosphated titanium samples. No significant differences were found between dogs or implant sites. Discussion and Conclusion: Acid-etched only implants showed significantly higher mineral apposition rates compared to acid-etched, phosphate-coated implants. PMID:20369085

  16. 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

  17. The effect of undissociated lactic acid on Staphylococcus aureus growth and enterotoxin A production.

    PubMed

    Rosengren, Asa; Lindblad, Mats; Lindqvist, Roland

    2013-03-15

    The potential of Staphylococcus aureus cheese isolates to grow and produce staphylococcal enterotoxin A under conditions typical for cheese making was investigated in three broth experiments. The effect of the concentration of undissociated lactic acid (HLac) in conjunction with specific pH values was studied by adjusting pH at a single concentration of lactic acid. First, the time-to-growth of S. aureus was modelled by using survival analysis and absorbance data obtained from an automated turbidity reader. The fitted model describes the time to growth and indicates the growth ⁄ no growth boundary of S. aureus as a function of HLac concentration, temperature and water activity. Second, growth rates and lag times of S. aureus were estimated after two different pre-treatments in skim milk at three HLac concentrations and two temperatures based on optical detection times of serial dilutions of bacterial solutions. Growth rates differed between strains, and increased with increasing temperature and decreasing HLac concentration. Preliminary results indicate that lag times were dependent on pre-treatment suggesting that the growth potential of S. aureus in cheese curd may be greater if milk is used immediately after milking compared to holding at 4°C after milking. Third, growth, inactivation, and enterotoxin A production of S. aureus strains were investigated at twelve combinations of HLac concentration and temperature. Concentrations of enterotoxin A increased linearly during the first four days, with a production rate increasing with increasing temperature and decreasing HLac concentration. Significant amounts of enterotoxin A were produced during extended incubation, up to 14days, but then initial pH had changed. This highlights a potential limitation of modelling based on the initial environmental conditions in batch experiments. In summary, ranges of time-to-growth, growth rates, lag times and enterotoxin A production rates of S. aureus in the presence of HLac

  18. Oxidation of dimethylselenide by δMnO2: oxidation product and factors affecting oxidation rate

    USGS Publications Warehouse

    Wang, Bronwen; Burau, Richard G.

    1995-01-01

    Volatile dimethylselenide (DMSe) was transformed to a nonvolatile Se compound in a ??-MnO2 suspension. The nonvolatile product was a single compound identified as dimethylselenoxide based on its mass spectra pattern. After 24 h, 100% of the DMSe added to a ??-MnO2 suspension was converted to nonpurgable Se as opposed to 20%, 18%, and 4% conversion for chromate, permanganate, and the filtrate from the suspension, respectively. Manganese was found in solution after reaction. These results imply that the reaction between manganese oxide and DMSe was a heterogeneous redox reaction involving solid phase ??-MnO2 and solution phase DMSe. Oxidation of DMSe to dimethylselenoxide [OSe(CH3)2] by a ??-MnO2 suspension appears to be first order with respect to ??-MnO2, to DMSe, and to hydrogen ion with an overall rate law of d[OSe(CH3)2 ]/dt = 95 M-2 min-1 [MnO2]1[DMSe]1[H+]1 for the MnO2 concentration range of 0.89 ?? 10-3 - 2.46 ?? 10-3 M, the DMSe concentration range of 3.9 ?? 10-7 - 15.5 ?? 10-7 M Se, and a hydrogen ion concentation range of 7.4 ?? 10-6 -9.5 ?? 10-8 M. A general surface site adsorption model is consistent with this rate equation if the uncharged |OMnOH is the surface adsorption site. DMSe acts as a Lewis base, and the manganese oxide surface acts as a Lewis acid. DMSe adsorption to |OMnOH can be viewed as a Lewis acid/ base complex between the largely p orbitals of the DMSe lone pair and the unoccupied eg orbitals on manganese oxide. For such a complex, frontier molecular orbital theory predicts electron transfer to occur via an inner-sphere complex between the DMSe and the manganese oxide. ?? 1995 American Chemical Society.

  19. Microbial production of amino acids and derived chemicals: synthetic biology approaches to strain development.

    PubMed

    Wendisch, Volker F

    2014-12-01

    Amino acids are produced at the multi-million-ton-scale with fermentative production of l-glutamate and l-lysine alone being estimated to amount to more than five million tons in the year 2013. Metabolic engineering constantly improves productivities of amino acid producing strains, mainly Corynebacterium glutamicum and Escherichia coli strains. Classical mutagenesis and screening have been accelerated by combination with intracellular metabolite sensing. Synthetic biology approaches have allowed access to new carbon sources to realize a flexible feedstock concept. Moreover, new pathways for amino acid production as well as fermentative production of non-native compounds derived from amino acids or their metabolic precursors were developed. These include dipeptides, α,ω-diamines, α,ω-diacids, keto acids, acetylated amino acids and ω-amino acids. PMID:24922334

  20. Aqueous chlorination of mefenamic acid: kinetics, transformation by-products and ecotoxicity assessment.

    PubMed

    Adira Wan Khalit, Wan Nor; Tay, Kheng Soo

    2016-05-18

    Mefenamic acid (Mfe) is one of the most frequently detected nonsteroidal anti-inflammatory drugs in the environment. This study investigated the kinetics and the transformation by-products of Mfe during aqueous chlorination. The potential ecotoxicity of the transformation by-products was also evaluated. In the kinetic study, the second-order rate constant (kapp) for the reaction between Mfe and free available chlorine (FAC) was determined at 25 ± 0.1 °C. The result indicated that the degradation of Mfe by FAC is highly pH-dependent. When the pH was increased from 6 to 8, it was found that the kapp for the reaction between Mfe and FAC was decreased from 16.44 to 4.4 M(-1) s(-1). Characterization of the transformation by-products formed during the chlorination of Mfe was carried out using liquid chromatography-quadrupole time-of-flight accurate mass spectrometry. Four major transformation by-products were identified. These transformation by-products were mainly formed through hydroxylation, chlorination and oxidation reactions. Ecotoxicity assessment revealed that transformation by-products, particularly monohydroxylated Mfe which is more toxic than Mfe, can be formed during aqueous chlorination. PMID:27062128

  1. The effects of acid deposition on sulfate reduction and methane production in peatlands

    NASA Technical Reports Server (NTRS)

    Murray, Georgia L.; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Peatlands, as fens and bods, make up a large percentage of northern latitude terrestrial environments. They are organic rich and support an active community of anaerobic bacteria, such as methanogenic and sulfate-reducing bacteria. The end products of these microbial activities, methane and hydrogen sulfide, are important components in the global biogeochemical cycles of carbon and sulfur. Since these two bacterial groups compete for nutritional substrates, increases in sulfate deposition due to acid rain potentially can disrupt the balance between these processes leading to a decrease in methane production and emission. This is significant because methane is a potent greenhouse gas that effects the global heat balance. A section of Mire 239 in the Experimental Lakes Area, in Northwestern Ontario, was artificially acidified and rates of sulfate reduction and methane production were measured with depth. Preliminary results suggested that methane production was not affected immediately after acidification. However, concentrations of dissolved methane decreased and dissolved sulfide increased greatly after acidification and both took several days to recover. The exact mechanism for the decrease in methane was not determined. Analyses are under way which will be used to determine rates of sulfate reduction. These results will be available by Spring and will be discussed.

  2. Photocatalytic hydrogen production from biomass-derived compounds: a case study of citric acid.

    PubMed

    Alkaim, Ayad F; Kandiel, Tarek A; Dillert, Ralf; Bahnemann, Detlef W

    2016-11-01

    Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products. PMID:26930545

  3. Cultivation of Nannochloropsis for eicosapentaenoic acid production in wastewaters of pulp and paper industry.

    PubMed

    Polishchuk, Anna; Valev, Dimitar; Tarvainen, Marko; Mishra, Sujata; Kinnunen, Viljami; Antal, Taras; Yang, Baoru; Rintala, Jukka; Tyystjärvi, Esa

    2015-10-01

    The eicosapentaenoic acid (EPA) containing marine microalga Nannochloropsis oculata was grown in an effluent from anaerobic digestion of excess activated sludge from a wastewater treatment plant serving a combination of a pulp and a paper mill and a municipality (digester effluent, DE), mixed with the effluent of the same wastewater treatment plant. The maximum specific growth rate and photosynthesis of N. oculata were similar in the DE medium and in artificial sea water medium (ASW) but after 7 days, algae grown in the DE medium contained seven times more triacylglycerols (TAGs) per cell than cells grown in ASW, indicating mild stress in the DE medium. However, the volumetric rate of EPA production was similar in the ASW and DE media. The results suggest that N. oculata could be used to produce EPA, utilizing the nutrients available after anaerobic digestion of excess activated sludge of a pulp and paper mill. PMID:26162525

  4. Production of lactic acid using a new homofermentative Enterococcus faecalis isolate.

    PubMed

    Subramanian, Mohan Raj; Talluri, Suvarna; Christopher, Lew P

    2015-03-01

    Lactic acid is an intermediate-volume specialty chemical for a wide range of food and industrial applications such as pharmaceuticals, cosmetics and chemical syntheses. Although lactic acid production has been well documented, improved production parameters that lead to reduced production costs are always of interest in industrial developments. In this study, we describe the production of lactic acid at high concentration, yield and volumetric productivity utilizing a novel homofermentative, facultative anaerobe Enterococcus faecalis CBRD01. The highest concentration of 182 g lactic acid l(-1) was achieved after 38 h of fed-batch fermentation on glucose. The bacterial isolate utilized only 2-13% of carbon for its growth and energy metabolism, while 87-98% of carbon was converted to lactic acid at an overall volumetric productivity of 5 g l(-1)  h(-1). At 13 h of fermentation, the volumetric productivity of lactate production reached 10.3 g l(-1)  h(-1), which is the highest ever reported for microbial production of lactic acid. The lactic acid produced was of high purity as formation of other metabolites was less than 0.1%. The present investigation demonstrates a new opportunity for enhanced production of lactic acid with potential for reduced purification costs. PMID:24894833

  5. Bounding f(R) gravity by particle production rate

    NASA Astrophysics Data System (ADS)

    Capozziello, Salvatore; Luongo, Orlando; Paolella, Mariacristina

    2016-02-01

    Several models of f(R) gravity have been proposed in order to address the dark side problem in cosmology. However, these models should be constrained also at ultraviolet scales in order to achieve some correct fundamental interpretation. Here, we analyze this possibility comparing quantum vacuum states in given f(R) cosmological backgrounds. Specifically, we compare the Bogolubov transformations associated to different vacuum states for some f(R) models. The procedure consists in fixing the f(R) free parameters by requiring that the Bogolubov coefficients can be correspondingly minimized to be in agreement with both high redshift observations and quantum field theory predictions. In such a way, the particle production is related to the value of the Hubble parameter and then to the given f(R) model. The approach is developed in both metric and Palatini formalism.

  6. Enhanced phenylpyruvic acid production with Proteus vulgaris in fed-batch and continuous fermentation.

    PubMed

    Coban, Hasan B; Demirci, Ali; Patterson, Paul H; Elias, Ryan J

    2016-01-01

    Phenylpyruvic acid is a deaminated form of phenylalanine and is used in various areas such as development of cheese and wine flavors, diagnosis of phenylketonuria, and to decrease excessive nitrogen accumulation in the manure of farm animals. However, reported phenylpyruvic acid fermentation studies in the literature have been usually performed at shake-flask scale with low production. In this study, phenylpyruvic acid production was evaluated in bench-top bioreactors by conducting fed-batch and continuous fermentation for the first time. As a result, maximum phenylpyruvic acid concentrations increased from 1350 mg/L (batch fermentation) to 2958 mg/L utilizing fed-batch fermentation. Furthermore, phenylpyruvic acid productivity was increased from 48 mg/L/hr (batch fermentation) to 104 and 259 mg/L/hr by conducting fed-batch and continuous fermentation, respectively. Overall, this study demonstrated that fed-batch and continuous fermentation significantly improved phenylpyruvic acid production in bench-scale bioreactor production. PMID:25569523

  7. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

    PubMed Central

    Abad, Sergi; Turon, Xavier

    2015-01-01

    Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA) when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM) with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1), biomass (0.7–0.8 g cells/g Substrate) and product (0.14–0.15 g DHA/g cells) yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct. PMID:26690180

  8. Biological and Chemical Properties of the Epidioxide Isomer of Abscisic Acid and its Rearrangement Products

    PubMed Central

    Sondheimer, Ernest; Michniewicz, Barbara M.; Powell, Loyd E.

    1969-01-01

    The growth inhibitory activity of the epidioxide (II), a precursor in the synthesis of abscisic acid (ABA), has been confirmed with additional assay systems. Under physiological conditions the epidioxide is rearranged to give ABA and an isomer of ABA which has probably the structure V. This major product has very low, if any, biological activity. The biological activity of the epidioxide is explained by its partial conversion (about 20%) to ABA. The reaction rate was enhanced by heavy metal ions and decreased by EDTA. At pH 12.5, the decomposition of the epidioxide is slower than it is near neutrality and ABA is the predominant product. In the biological systems studied the activity of the epidioxide can be accounted for by nonenzymatic conversion to ABA. PMID:16657047

  9. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization.

    PubMed

    Abad, Sergi; Turon, Xavier

    2015-12-01

    Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA) when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM) with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10-0.12 h(-1)), biomass (0.7-0.8 g cells/g Substrate) and product (0.14-0.15 g DHA/g cells) yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct. PMID:26690180

  10. Effects of fatty acid activation on photosynthetic production of fatty acid-based biofuels in Synechocystis sp. PCC6803

    PubMed Central

    2012-01-01

    Background Direct conversion of solar energy and carbon dioxide to drop in fuel molecules in a single biological system can be achieved from fatty acid-based biofuels such as fatty alcohols and alkanes. These molecules have similar properties to fossil fuels but can be produced by photosynthetic cyanobacteria. Results Synechocystis sp. PCC6803 mutant strains containing either overexpression or deletion of the slr1609 gene, which encodes an acyl-ACP synthetase (AAS), have been constructed. The complete segregation and deletion in all mutant strains was confirmed by PCR analysis. Blocking fatty acid activation by deleting slr1609 gene in wild-type Synechocystis sp. PCC6803 led to a doubling of the amount of free fatty acids and a decrease of alkane production by up to 90 percent. Overexpression of slr1609 gene in the wild-type Synechocystis sp. PCC6803 had no effect on the production of either free fatty acids or alkanes. Overexpression or deletion of slr1609 gene in the Synechocystis sp. PCC6803 mutant strain with the capability of making fatty alcohols by genetically introducing fatty acyl-CoA reductase respectively enhanced or reduced fatty alcohol production by 60 percent. Conclusions Fatty acid activation functionalized by the slr1609 gene is metabolically crucial for biosynthesis of fatty acid derivatives in Synechocystis sp. PCC6803. It is necessary but not sufficient for efficient production of alkanes. Fatty alcohol production can be significantly improved by the overexpression of slr1609 gene. PMID:22433663

  11. Genotype, production system and sex effects on fatty acid composition of meat from goat kids.

    PubMed

    Özcan, Mustafa; Demirel, Gulcan; Yakan, Akın; Ekiz, Bülent; Tölü, Cemil; Savaş, Türker

    2015-02-01

    Two trials were performed to assess the meat fatty acid profile of goat kids from different genotypes, production systems and sex. In the first trial, genotype effect was determined in 24 suckling male kids from Turkish Saanen, Maltese and Gokceada breeds. In the second trial, male and female Gokceada Goat kids were used to compare the effect of extensive and semi-intensive production systems on fatty acid composition of meat. Significant genotype effect was observed in the percentages of myristic acid (C14:0), palmitic acid (C16:0), oleic acid (C18:1 n-9), linolenic acid (C18:3 n-3), arachidonic acid (C20:4 n-6) and docosahexaenoic acid (C22:6 n-3), despite no differences on the ratios of polyunsaturated fatty acids to saturated fatty acids (PUFA/SFA) and n-6/n-3 (P > 0.05). The effect of production system had also significant effects on fatty acids, but sex only influenced significantly stearic acid (C18:0), C18:1 n-9 and C18:3 n-3 fatty acids and total PUFA level and PUFA/SFA ratio. This study confirms that dairy breeds are prone to produce higher levels of unsaturated fatty acids in their muscle. Meanwhile, meat from Gokceada goat kids, which is one of the indigenous breeds in Turkey, had similar PUFA/SFA and n-6/n-3 ratios to Turkish Saanen and Maltase. PMID:25186278

  12. Production and applications of carbohydrate-derived sugar acids as generic biobased chemicals.

    PubMed

    Mehtiö, Tuomas; Toivari, Mervi; Wiebe, Marilyn G; Harlin, Ali; Penttilä, Merja; Koivula, Anu

    2016-10-01

    This review considers the chemical and biotechnological synthesis of acids that are obtained by direct oxidation of mono- or oligosaccharide, referred to as sugar acids. It focuses on sugar acids which can be readily derived from plant biomass sources and their current and future applications. The three main classes of sugar acids are aldonic, aldaric and uronic acids. Interest in organic acids derived from sugars has recently increased, as part of the interest to develop biorefineries which produce not only biofuels, but also chemicals to replace those currently derived from petroleum. More than half of the most desirable biologically produced platform chemicals are organic acids. Currently, the only sugar acid with high commercial production is d-gluconic acid. However, other sugar acids such as d-glucaric and meso-galactaric acids are being produced at a lower scale. The sugar acids have application as sequestering agents and binders, corrosion inhibitors, biodegradable chelators for pharmaceuticals and pH regulators. There is also considerable interest in the use of these molecules in the production of synthetic polymers, including polyamides, polyesters and hydrogels. Further development of these sugar acids will lead to higher volume production of the appropriate sugar acids and will help support the next generation of biorefineries. PMID:26177333

  13. Effects of folic acid and vitamin B12 supplementation on culling rate, diseases, and reproduction in commercial dairy herds.

    PubMed

    Duplessis, M; Girard, C L; Santschi, D E; Laforest, J-P; Durocher, J; Pellerin, D

    2014-01-01

    This study was undertaken to determine the effect of a combined folic acid and vitamin B12 supplement given in early lactation on culling rate, metabolic disorders and other diseases, and reproduction in commercial dairy herds. A total of 805 cows (271 primiparous and 534 multiparous cows) in 15 commercial dairy herds were involved. Every 2mo from February to December 2010 and within each herd, cows were assigned according to parity, previous 305-d milk production, and calving interval to 5mL of either (1) saline 0.9% NaCl (control group) or (2) 320mg of folic acid + 10mg of vitamin B12 (vitamin group). Treatments were administered weekly by intramuscular injections starting 3wk before the expected calving date until 8wk after parturition. A total of 221 cows were culled before the next dry period. Culling rate was not affected by treatment and was 27.5%; culling rate was greater for multiparous (32.2%) than for primiparous cows (18.8%). Within the first 60d in milk (DIM), 47 cows were culled, representing 21.3% of total culling, and no treatment effect was noted. Ketosis incidence based on a threshold ≥100µmol/L of β-hydroxybutyrate in milk was 38.3±2.9% for the vitamin group and 41.8±3.0% for the control group and was not affected by treatment. The combined supplement of folic acid and vitamin B12 did not decrease incidence of retained placenta, displaced abomasum, milk fever, metritis, or mastitis. However, the incidence of dystocia decreased by 50% in multiparous cows receiving the vitamin supplement, although no effect was observed in primiparous cows. The first breeding postpartum for multiparous cows occurred 3.8d earlier with the vitamin supplement compared with controls, whereas no treatment effect was seen for primiparous cows. Days open, first- and second-breeding conception rates, number of breedings per conception, and percentage of cows pregnant at 150 DIM were not affected by treatment. The reduced percentage of dystocia combined with the

  14. Intracellular pH Recovery Rates in Bivalve Hemocytes Following Exposure to Acidic Environmental Conditions

    NASA Astrophysics Data System (ADS)

    Croxton, A.; Wikfors, G. H.

    2012-12-01

    Predictions of ocean acidification effects upon carbonate shell-forming species have caused great concern for the future of shellfisheries. Nevertheless, bivalve species inhabiting an estuarine environment have evolved in these environments with fluctuating pH levels. Previous experimental studies conducted in our laboratory have demonstrated the ability of oyster hemocytes to maintain intracellular homeostasis under acidic external conditions. However, little information is known of this homeostatic mechanism in other molluscan shellfish species present in these same habitats. In the current study we propose to determine if other bivalve species of aquaculture interest also possess this intracellular regulation by applying an in vitro hemocyte pH-recovery assay, previously developed for oysters, on the northern quahog, Mercenaria mercenaria, the blue mussel, Mytilus edulis, and the softshell clam, Mya arenaria. Preliminary results from the determination of initial intracellular pH levels, the initial step in the rate recovery assay, indicated a pH range between 7.0-7.4. This range was comparable to initial values measured in oysters, and consistent with data reported in the current literature. The second step of the hemocyte pH-recovery assay involves exposing oyster hemocytes to acidic external conditions and measuring the ability of the hemocyte intracellular pH to maintain homeostasis (i.e. recovery rate). Results from the recovery rate process will be presented.

  15. Field rates for natural attenuation of arsenic in Tinto Santa Rosa acid mine drainage (SW Spain).

    PubMed

    Asta, Maria P; Ayora, Carlos; Acero, Patricia; Cama, Jordi

    2010-05-15

    Reactive transport modelling of the main processes related to the arsenic natural attenuation observed in the acid mine drainage (AMD) impacted stream of Tinto Santa Rosa (SW Spain) was performed. Despite the simplicity of the kinetic expressions used to deal with arsenic attenuation processes, the model reproduced successfully the major chemical trends observed along the acid discharge. Results indicated that the rate of ferrous iron oxidation was similar to the one obtained in earlier field studies in which microbial catalysis is reported to occur. With regard to the scaled arsenic oxidation rate, it is one order of magnitude faster than the values obtained under laboratory conditions suggesting the existence of a catalytic agent in the natural system. Schwertmannite precipitation rate, which was represented by a simple kinetic expression relying on Fe(III) and pH, was in the range calculated for other AMD impacted sites. Finally, the obtained distribution coefficients used for representing arsenic sorption onto Fe(III) precipitates were lower than those deduced from reported laboratory data. This discrepancy is attributed to a decrease in the schwertmannite arsenate sorption capacity as sulphate increases in the solution. PMID:20153577

  16. Suppression of Growth Rate of Colony-Associated Fungi by High Fructose Corn Syrup Feeding Supplement, Formic Acid, and Oxalic Acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Select colony-associated fungi (bee isolates). Absidia sp., Ascosphaera apis, Aspergillus flavus, Fusarium sp., Penicillium glabrum, Mucor sp., showed a 40% reduction in radial growth rate with formic acid, a 28% reduction with oxalic acid, and a 15% reduction with fructose and high fructose corn sy...

  17. LC/MS/MS identification of some folic acid degradation products after E-beam irradiation

    NASA Astrophysics Data System (ADS)

    Araújo, M. M.; Marchioni, E.; Zhao, M.; Kuntz, F.; Di Pascoli, T.; Villavicencio, A. L. C. H.; Bergaentzle, M.

    2012-08-01

    Folates belong to the B vitamin group based on the parental compound folic acid (FA). They are involved in important biochemical processes like DNA synthesis and repair. FA is composed of a pteridine ring, p-aminobenzoic acid and glutamate moieties. The human metabolism is not able to synthesize folates and therefore obtain them from diet. FA, a synthetic vitamin, is used as a food fortificant because of its low price, relative stability and increased bioavailability compared to natural folate forms. FA is known to be a sensitive compound easily degradable in aqueous solution by ultraviolet and visible light towards various by-products. Irradiation is a process for preservation of foods that uses accelerated electrons, gamma rays or X-rays. Irradiation is proposed for the treatment of various food products, eliminating or reducing pathogens and insects, increasing the storage time and replacing chemical fumigants. This study concerns the identification of degradation products of FA after E-beam irradiation. FA aqueous solutions were irradiated with a Van de Graaff electrons beam accelerator (2 MeV, 100 μA current, 20 cm scan width, dose rate about 2 kGy/s). Applied doses were between 0 (control) and 10.0 kGy. Absorbed doses were monitored with FWT 60.00 radiochromic dosimeters.

  18. Production of Butyric Acid and Butanol from Biomass

    SciTech Connect

    David E. Ramey; Shang-Tian Yang

    2005-08-25

    Environmental Energy Inc has shown that BUTANOL REPLACES GASOLINE - 100 pct and has no pollution problems, and further proved it is possible to produce 2.5 gallons of butanol per bushel corn at a production cost of less than $1.00 per gallon. There are 25 pct more Btu-s available and an additional 17 pct more from hydrogen given off, from the same corn when making butanol instead of ethanol that is 42 pct more Btu-s more energy out than it takes to make - that is the plow to tire equation is positive for butanol. Butanol is far safer to handle than gasoline or ethanol. Butanol when substituted for gasoline gives better gas mileage and does not pollute as attested to in 10 states. Butanol should now receive the same recognition as a fuel alcohol in U.S. legislation as ethanol. There are many benefits to this technology in that Butanol replaces gasoline gallon for gallon as demonstrated in a 10,000 miles trip across the United States July-August 2005. No modifications at all were made to a 1992 Buick Park Avenue; essentially your family car can go down the road on Butanol today with no modifications, Butanol replaces gasoline. It is that simple. Since Butanol replaces gasoline more Butanol needs to be made. There are many small farms across America which can grow energy crops and they can easily apply this technology. There is also an abundance of plant biomass present as low-value agricultural commodities or processing wastes requiring proper disposal to avoid pollution problems. One example is in the corn refinery industry with 10 million metric tons of corn byproducts that pose significant environmental problems. Whey lactose presents another waste management problem, 123,000 metric tons US, which can now be turned into automobile fuel. The fibrous bed bioreactor - FBB - with cells immobilized in the fibrous matrix packed in the reactor has been successfully used for several organic acid fermentations, including butyric and propionic acids with greatly increased

  19. Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ.

    PubMed

    Pashaei, S; Ghoorchi, T; Yamchi, A

    2016-04-01

    An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro-organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed. PMID:26094995

  20. Soil calcium status and the response of stream chemistry to changing acidic deposition rates

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.; Lovett, Gary M.; Murdoch, Peter S.; Burns, Douglas A.; Stoddard, J.L.; Baldigo, Barry P.; Porter, J.H.; Thompson, A.W.

    1999-01-01

    Despite a decreasing trend in acidic deposition rates over the past two to three decades, acidified surface waters in the northeastern United States have shown minimal changes. Depletion of soil Ca pools has been suggested as a cause, although changes in soil Ca pools have not been directly related to long-term records of stream chemistry. To investigate this problem, a comprehensive watershed study was conducted in the Neversink River Basin, in the Catskill Mountains of New York, during 1991-1996. Spatial variations of atmospheric deposition, soil chemistry, and stream chemistry were evaluated over an elevation range of 817-1234 m to determine whether these factors exhibited elevational patterns. An increase in atmospheric deposition of SO4 with increasing elevation corresponded with upslope decreases of exchangeable soil base concentrations and acid-neutralizing capacity of stream water. Exchangeable base concentrations in homogeneous soil incubated within the soil profile for one year also decreased with increasing elevation. An elevational gradient in precipitation was not observed, and effects of a temperature gradient on soil properties were not detected. Laboratory leaching experiments with soils from this watershed showed that (1) concentrations of Ca in leachate increased as the concentrations of acid anions in added solution increased, and (2) the slope of this relationship was positively correlated with base saturation. Field and laboratory soil analyses are consistent with the interpretation that decreasing trends in acid-neutralizing capacity in stream water in the Neversink Basin, dating back to 1984, are the result of decreases in soil base saturation caused by acidic deposition.