Microbial community structures in algae cultivation ponds for bioconversion of agricultural wastes from livestock industry for feed production

USDA-ARS?s Scientific Manuscript database

Dynamics of seasonal microbial community compositions in algae cultivation ponds are complex. There is very limited knowledge on community compositions that may play significant roles in the bioconversion of manure nu¬trients to animal feed. Algae production is an alternative where land area for pro...

Systematic metabolic profiling and bioactivity assays for bioconversion of Aceraceae family.

PubMed

Park, Jinyong; Suh, Dong Ho; Singh, Digar; Lee, Sarah; Lee, Jong Seok; Lee, Choong Hwan

2018-01-01

Plants are an important and inexhaustible source of bioactive molecules in food, medicine, agriculture, and industry. In this study, we performed systematic liquid chromatography-mass spectrometry (LC-MS)-based metabolic profiling coupled with antioxidant assays for indigenous plant family extracts. Partial least-squares discriminant analysis of LC-MS datasets for the extracts of 34 plant species belonging to the families Aceraceae, Asteraceae, and Rosaceae showed that these species were clustered according to their respective phylogenies. In particular, seven Aceraceae species were clearly demarcated with higher average antioxidant activities, rationalizing their application for bioconversion studies. On the basis of further evaluation of the interspecies variability of metabolic profiles and antioxidant activities among Aceraceae family plants, we found that Acer tataricum (TA) extracts were clearly distinguished from those of other species, with a higher relative abundance of tannin derivatives. Further, we detected a strong positive correlation between most tannin derivatives and the observed higher antioxidant activities. Following Aspergillus oryzae-mediated fermentative bioconversion of Acer plant extracts, we observed a time-correlated (0-8 days) linear increase in antioxidant phenotypes for all species, with TA having the highest activity. Temporal analysis of the MS data revealed tannin bioconversion mechanisms with a relatively higher abundance of gallic acid (m/z 169) accumulated at the end of 8 days, particularly in TA. Similarly, quercetin precursor (glycoside) metabolites were also transformed to quercetin aglycones (m/z 301) in most Acer plant extracts. The present study underscores the efficacy of fermentative bioconversion strategies aimed at enhancing the quality and availability of bioactive metabolites from plant extracts.

Bioconversion of woody biomass to biofuel and lignin co-product using sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL)

Treesearch

Junyong Zhu; Chao Zhang; Roland Gleisner; Carl Houtman; Xuejun Pan

2016-01-01

Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) promises to provide efficient bioconversion of woody biomass into bioethanol and lignin co-products. Results from several laboratory and pilot-scale studies are presented to demonstrate SPORL performance, with comparisons to competing technologies. Excellent ethanol yields of up to...

Behavior of spores of Penicillium roquefortii during fed-batch bioconversion of octanoic acid into 2-heptanone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larroche, C.; Besson, I.; Gros, J.B.

1994-09-05

The bioconversion of octanoic acid into 2-heptanone by spores of Penicillium roquefortii is performed using a fed-batch technique with pH control by addition of the liquid substrate itself. The early stage of this process takes place with a high bioconversion rate and high yield. These values then decrease as a result of germination and growth of the biocatalyst. An optimization strategy for the process would thus be to improve the characteristics of this first period, i.e., increase its duration and the reaction rate. An increase in duration is evidenced in two cases: (1) under oxygen limitation; and (2) when themore » spore content in the medium is less than 10[sup 7] spores/mL. These conditions give insufficient overall bioconversion rates; better optimization should be achieved without oxygen limitation and with high spore content. Characterization of the first period by material and bioenergetic balances suggests that an increase in the ethanol content of the medium, which acts as an energy source and a permeabilizer, and the use of a specific inhibitor of the Krebs cycle, may be a way to further improve the biocatalyst performance and stability.« less

Bioconversion of D-glucose into D-glucosone by glucose 2-oxidase from Coriolus versicolor at moderate pressures.

PubMed

Karmali, Amin; Coelho, José

2011-04-01

Glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2-oxidoreductase, EC 1.1.3.10) from Coriolus versicolor catalyses the oxidation of D-glucose at carbon 2 in the presence of molecular O₂ producing D-glucosone (2-keto-glucose and D-arabino-2-hexosulose) and H₂O₂. It was used to convert D-glucose into D-glucosone at moderate pressures (i.e. up to 150 bar) with compressed air in a modified commercial batch reactor. Several parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, [enzyme], [glucose], pH, temperature, nature of fluid and the presence of catalase. Glucose 2-oxidase was purified by immobilized metal affinity chromatography on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. The rate of bioconversion of D-glucose increased with the pressure since an increase in the pressure with compressed air resulted in higher rates of conversion. On the other hand, the presence of catalase increased the rate of reaction which strongly suggests that H₂O₂ acted as inhibitor for this reaction. The rate of bioconversion of D-glucose by glucose 2-oxidase in the presence of either nitrogen or supercritical CO₂ at 110 bar was very low compared with the use of compressed air at the same pressure. The optimum temperature (55 °C) and pH (5.0) of D-glucose bioconversion as well as kinetic parameters for this enzyme were determined under moderate pressure. The activation energy (E (a)) was 32.08 kJ mol⁻¹ and kinetic parameters (V(max), K(m), K(cat) and K(cat)/K(m)) for this bioconversion were 8.8 U mg⁻¹ protein, 2.95 mM, 30.81 s⁻¹ and 10,444.06 s⁻¹ M⁻¹, respectively. The biomass of C. versicolor as well as the cell-free extract containing glucose 2-oxidase activity were also useful for bioconversion of D-glucose at moderate pressures. The enzyme was apparently stable at moderate pressures since such pressures did not affect significantly the enzyme activity.

Biomass pyrolysis liquid to citric acid via 2-step bioconversion.

PubMed

Yang, Zhiguang; Bai, Zhihui; Sun, Hongyan; Yu, Zhisheng; Li, Xingxing; Guo, Yifei; Zhang, Hongxun

2014-12-31

The use of fossil carbon sources for fuels and petrochemicals has serious impacts on our environment and is unable to meet the demand in the future. A promising and sustainable alternative is to substitute fossil carbon sources with microbial cell factories converting lignocellulosic biomass into desirable value added products. However, such bioprocesses require tolerance to inhibitory compounds generated during pretreatment of biomass. In this study, the process of sequential two-step bio-conversion of biomass pyrolysis liquid containing levoglucosan (LG) to citric acid without chemical detoxification has been explored, which can greatly improve the utilization efficiency of lignocellulosic biomass. The sequential two-step bio-conversion of corn stover pyrolysis liquid to citric acid has been established. The first step conversion by Phanerochaete chrysosporium (P. chrysosporium) is desirable to decrease the content of other compounds except levoglucosan as a pretreatment for the second conversion. The remaining levoglucosan in solution was further converted into citric acid by Aspergillus niger (A. niger) CBX-209. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology. Under experimental conditions, levoglucosan yield is 12% based on the feedstock and the citric acid yield can reach 82.1% based on the levoglucosan content in the pyrolysis liquid (namely 82.1 g of citric acid per 100 g of levoglucosan). The study shows that P. chrysosporium and A. niger have the potential to be used as production platforms for value-added products from pyrolyzed lignocellulosic biomass. Selected P. chrysosporium is able to decrease the content of other compounds except levoglucosan and levoglucosan can be further converted into citric acid in the residual liquids by A. niger. Thus the conversion of cellulose to citric acid is completed by both pyrolysis and bio-conversion technology.

Advanced Effect of Moringa oleifera Bioconversion by Rhizopus oligosporus on the Treatment of Atopic Dermatitis: Preliminary Study

PubMed Central

Hur, Sang-sun; Choi, Suk-won; Lee, Dong-ryul; Park, Jong-hwan

2018-01-01

This study was conducted to determine if topical application of Moringa oleifera extracts and its bioconversion product fermented by Rhizopus oligosporus has therapeutic properties enhancement for treatment of atopic dermatitis. Rhizopus oligosporus (KCCM 11232P) was used to ferment Moringa leaves' extracts in this study. Comparison of organic acids and flavonols in Moringa simple extracts and their fermented product by HPLC analysis revealed that concentration of organic acids and flavonols of bioconversion product was lower than that of hot water extracts. The fermentation process is used as a nutrient for isolation of each component by microorganisms and growth of microorganisms. The results demonstrated that MF extracts effectively reduced clinical features based on macrography, scratching count, and severity scores, as well as model's serum IgE level, including histopathological analyses. PMID:29576799

Immobilization on graphene oxide improves the thermal stability and bioconversion efficiency of D-psicose 3-epimerase for rare sugar production.

PubMed

Dedania, Samir R; Patel, Manisha J; Patel, Dijit M; Akhani, Rekha C; Patel, Darshan H

2017-12-01

D-Psicose (D-ribo-2-hexulose or D-allulose), an epimer of D-fructose is considered as a rare low-calorie sugar displaying important physiological functions. Enzymatic production using ketose 3-epimerases is the feasible process for the production of D-Psicose. However, major drawbacks in application of ketose 3-epimerases are bioconversion efficiency and reusability of the enzyme. We have attempted immobilization of ketose 3-epimerases from Agrobacterium tumefaciens (agtu) D-psicose 3-epimerase (DPEase) on graphene oxide. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Thermo gravimetric analysis (TGA) showed that the enzyme was successfully immobilized on the graphene oxide. Graphene oxide immobilized agtu-DPEase (GO-agtu-DPEase) shows pH optima at 7.5 and 60°C as higher working temperature. Significant improvement in thermal stability was observed which showed half-life of 720min at 60°C whereas Agrobacterium tumefaciens (agtu) DPEase displayed 3.99min. At equilibrium, 40:60 (D-psicose: D-fructose) the bioconversion efficiency was accounted for Graphene oxide immobilized DPEase which is higher than the agtu-DPEase. Graphene oxide immobilized DPEase showed bioconversion efficiency up to 10 cycles of reusability. Copyright © 2017 Elsevier Inc. All rights reserved.

Designer biomass for next-generation biorefineries: leveraging recent insights into xylan structure and biosynthesis.

PubMed

Smith, Peter J; Wang, Hsin-Tzu; York, William S; Peña, Maria J; Urbanowicz, Breeanna R

2017-01-01

Xylans are the most abundant noncellulosic polysaccharides in lignified secondary cell walls of woody dicots and in both primary and secondary cell walls of grasses. These polysaccharides, which comprise 20-35% of terrestrial biomass, present major challenges for the efficient microbial bioconversion of lignocellulosic feedstocks to fuels and other value-added products. Xylans play a significant role in the recalcitrance of biomass to degradation, and their bioconversion requires metabolic pathways that are distinct from those used to metabolize cellulose. In this review, we discuss the key differences in the structural features of xylans across diverse plant species, how these features affect their interactions with cellulose and lignin, and recent developments in understanding their biosynthesis. In particular, we focus on how the combined structural and biosynthetic knowledge can be used as a basis for biomass engineering aimed at developing crops that are better suited as feedstocks for the bioconversion industry.

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

PubMed Central

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

2013-01-01

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

Influence of dietary spices on the in vivo absorption of ingested β-carotene in experimental rats.

PubMed

Veda, Supriya; Srinivasan, Krishnapura

2011-05-01

Animal studies were conducted to evaluate the influence of dietary spice compounds, piperine, capsaicin and ginger, on the absorption of orally administered β-carotene and its conversion to vitamin A. In rats maintained on these spice-containing diets for 8 weeks, concentrations of β-carotene and retinol were determined in the serum, liver and intestine 4 h after a single oral administration of β-carotene. β-Carotene concentration was significantly increased in the serum, liver and intestine of piperine- and ginger-fed rats, suggesting improved absorption of β-carotene. However, retinol concentration was not significantly changed in these animals, suggesting that the bioconversion of β-carotene to vitamin A was not similarly influenced. Between the two enzymes involved in the bioconversion of β-carotene to vitamin A, the activity of intestinal and hepatic β-carotene 15,15'-dioxygenase was either unaffected or lowered by these spice treatments. The activity of intestinal and hepatic retinal reductase was unaffected by the dietary spices. Activities of these two enzymes involved in the bioconversion of β-carotene to retinal were inhibited by the test spices in vitro, thus corroborating with the in vivo observation. Although the bioconversion of β-carotene was not promoted, increased absorption and tissue levels of β-carotene by the dietary spices may contribute to a higher antioxidant protection.

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa.

PubMed

Dogaris, Ioannis; Gkounta, Olga; Mamma, Diomi; Kekos, Dimitris

2012-07-01

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 °C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and β-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively.

A novel process for enhancing oil production in algae biorefineries through bioconversion of solid by-products.

PubMed

Trzcinski, Antoine P; Hernandez, Ernesto; Webb, Colin

2012-07-01

This paper focuses on a novel process for adding value to algae residue. In current processes oleaginous microalgae are grown and harvested for lipid production leaving a lipid-free algae residue. The process described here includes conversion of the carbohydrate fraction into glucose prior to lipid extraction. This can be fermented to produce up to 15% additional lipids using another oleaginous microorganism. It was found that in situ enzymes can hydrolyze storage carbohydrates in the algae into glucose and that a temperature of 55 °C for about 20 h gave the best glucose yield. Up to 75% of available carbohydrates were converted to a generic fermentation feedstock containing 73 g/L glucose. The bioconversion step was found to increase the free water content by 60% and it was found that when the bioconversion was carried out prior to the extraction step, it improved the solvent extractability of lipids from the algae. Copyright © 2012 Elsevier Ltd. All rights reserved.

Bio-conversion of apple pomace into ethanol and acetic acid: Enzymatic hydrolysis and fermentation.

PubMed

Parmar, Indu; Rupasinghe, H P Vasantha

2013-02-01

Enzymatic hydrolysis of cellulose present in apple pomace was investigated using process variables such as enzyme activity of commercial cellulase, pectinase and β-glucosidase, temperature, pH, time, pre-treatments and end product separation. The interaction of enzyme activity, temperature, pH and time had a significant effect (P<0.05) on release of glucose. Optimal conditions of enzymatic saccharification were: enzyme activity of cellulase, 43units; pectinase, 183units; β-glucosidase, 41units/g dry matter (DM); temperature, 40°C; pH 4.0 and time, 24h. The sugars were fermented using Saccharomyces cerevisae yielding 19.0g ethanol/100g DM. Further bio-conversion using Acetobacter aceti resulted in the production of acetic acid at a concentration of 61.4g/100g DM. The present study demonstrates an improved process of enzymatic hydrolysis of apple pomace to yield sugars and concomitant bioconversion to produce ethanol and acetic acid. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fungal Bioconversion of Lignocellulosic Residues; Opportunities & Perspectives

PubMed Central

Dashtban, Mehdi; Schraft, Heidi; Qin, Wensheng

2009-01-01

The development of alternative energy technology is critically important because of the rising prices of crude oil, security issues regarding the oil supply, and environmental issues such as global warming and air pollution. Bioconversion of biomass has significant advantages over other alternative energy strategies because biomass is the most abundant and also the most renewable biomaterial on our planet. Bioconversion of lignocellulosic residues is initiated primarily by microorganisms such as fungi and bacteria which are capable of degrading lignocellulolytic materials. Fungi such as Trichoderma reesei and Aspergillus niger produce large amounts of extracellular cellulolytic enzymes, whereas bacterial and a few anaerobic fungal strains mostly produce cellulolytic enzymes in a complex called cellulosome, which is associated with the cell wall. In filamentous fungi, cellulolytic enzymes including endoglucanases, cellobiohydrolases (exoglucanases) and β-glucosidases work efficiently on cellulolytic residues in a synergistic manner. In addition to cellulolytic/hemicellulolytic activities, higher fungi such as basidiomycetes (e.g. Phanerochaete chrysosporium) have unique oxidative systems which together with ligninolytic enzymes are responsible for lignocellulose degradation. This review gives an overview of different fungal lignocellulolytic enzymatic systems including extracellular and cellulosome-associated in aerobic and anaerobic fungi, respectively. In addition, oxidative lignocellulose-degradation mechanisms of higher fungi are discussed. Moreover, this paper reviews the current status of the technology for bioconversion of biomass by fungi, with focus on mutagenesis, co-culturing and heterologous gene expression attempts to improve fungal lignocellulolytic activities to create robust fungal strains. PMID:19774110

Reverse membrane bioreactor: Introduction to a new technology for biofuel production.

PubMed

Mahboubi, Amir; Ylitervo, Päivi; Doyen, Wim; De Wever, Heleen; Taherzadeh, Mohammad J

2016-01-01

The novel concept of reverse membrane bioreactors (rMBR) introduced in this review is a new membrane-assisted cell retention technique benefiting from the advantageous properties of both conventional MBRs and cell encapsulation techniques to tackle issues in bioconversion and fermentation of complex feeds. The rMBR applies high local cell density and membrane separation of cell/feed to the conventional immersed membrane bioreactor (iMBR) set up. Moreover, this new membrane configuration functions on basis of concentration-driven diffusion rather than pressure-driven convection previously used in conventional MBRs. These new features bring along the exceptional ability of rMBRs in aiding complex bioconversion and fermentation feeds containing high concentrations of inhibitory compounds, a variety of sugar sources and high suspended solid content. In the current review, the similarities and differences between the rMBR and conventional MBRs and cell encapsulation regarding advantages, disadvantages, principles and applications for biofuel production are presented and compared. Moreover, the potential of rMBRs in bioconversion of specific complex substrates of interest such as lignocellulosic hydrolysate is thoroughly studied. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Pilot scale repeated fed-batch fermentation processes of the wine yeast Dekkera bruxellensis for mass production of resveratrol from Polygonum cuspidatum.

PubMed

Kuo, Hsiao-Ping; Wang, Reuben; Lin, Yi-Sheng; Lai, Jinn-Tsyy; Lo, Yi-Chen; Huang, Shyue-Tsong

2017-11-01

Resveratrol has long been used as an ingredient in functional foods. Currently, Polygonum cuspidatum extract is the greatest natural source for resveratrol because of high concentrations of glycosidic-linked resveratrol. Thus, developing a cost-effective procedure to hydrolyze glucoside could substantially enhance resveratrol production from P. cuspidatum. This study selected Dekkera bruxellensis from several microorganisms based on its bioconversion and enzyme-specific activities. We demonstrated that the cells could be reused at least nine times while maintaining an average of 180.67U/L β-glucosidase activity. The average resveratrol bioconversion efficiency within five rounds of repeated usage was 108.77±0.88%. This process worked effectively when the volume was increased to 1200L, a volume at which approximately 35mgL -1 h -1 resveratrol per round was produced. This repeated fed-batch bioconversion process for resveratrol production is comparable to enzyme or cell immobilization strategies in terms of reusing cycles, but without incurring additional costs for immobilization. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioconversion of D-psicose to D-tagatose and D-talitol by Mucoraceae fungi.

PubMed

Yoshihara, Kazutoshi; Shinohara, Yoshihiro; Hirotsu, Takahiro; Izumori, Ken

2006-03-01

Rhizopus oryzae MYA-2483, which cannot utilize D-psicose as a sole source of carbon, converted D-psicose to two other compounds. These compounds were identified by NMR and IR as D-tagatose and D-talitol. In this study, we describe for the first time the bioconversion of D-psicose to D-tagatose. Various strains of Mucoraceae fungi, to which R. oryzae MYA-2483 belongs, exhibited conversion activity similar to that of R. oryzae MYA-2483. There is the possibility that a considerable number of fungi belonging to Mucoraceae possess such D-psicose conversion activity.

Enzymes and microorganisms in food industry waste processing and conversion to useful products: a review of the literature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carroad, P.A.; Wilke, C.R.

1976-12-01

Bioconversion of food processing wastes is receiving increased attention with the realization that waste components represent an available and utilizable resource for conversion to useful products. Liquid wastes are characterized as dilute streams containing sugars, starches, proteins, and fats. Solid wastes are generally cellulosic, but may contain other biopolymers. The greatest potential for economic bioconversion is represented by processes to convert cellulose to glucose, glucose to alcohol and protein, starch to invert sugar, and dilute waste streams to methane by anaerobic digestion. Microbial or enzymatic processes to accomplish these conversions are described.

Limitations of in silico predictability of specificity of co-immobilised cytochromes P450 and mimics in food-bioprocessing.

PubMed

Wiseman, Alan

2003-04-01

Cytochromes P450 (EC 1.14.14.1) are mixed function oxidases (oxygenases) that can catalyse redox bioconversions of food components. Also, efficacious removal of undesirable components can be achieved using solid-support immobilised enzyme (IME) of a selection from 2700 isoforms of cytochromes P450 (CYP). Cytochromes P450 co-immobilised with other enzymes, or protein receptors, may be used to confer a secondary order of regio- or stereo-specificity of chiral bioconversion: these can be predictable in silico by utilisation of QSARs (quantitative structure/activity relationships).

Molecular characterization and expression analysis of heat shock protein 70 and 90 from Hermetia illucens reared in a food waste bioconversion pilot plant.

PubMed

Giannetto, Alessia; Oliva, Sabrina; Mazza, Lorenzo; Mondello, Giovanni; Savastano, Domenico; Mauceri, Angela; Fasulo, Salvatore

2017-09-05

Two full-length cDNAs of heat shock protein (HSP) genes (Hihsp70 and Hihsp90) were cloned from the black soldier fly (BSF) Hermetia illucens larvae reared in a food waste bioconversion pilot plant. The Hihsp70 and Hihsp90 transcripts were 2243 and 2507bp long, contained 1923 and 2166bp open reading frames encoding proteins of 640 and 721 amino acids with a molecular mass of 69.8 and 83kDa, respectively. Comparative analysis of protein sequences revealed the presence of the conserved HSP motifs in both proteins, showing high homology to their counterparts in other insect species from six different orders. Hihsp70 and Hihsp90 transcriptional expression profiles during two key developmental stages in the bioconversion process were evaluated by quantitative real time PCR showing that both genes were modulated during larval development. HiHsp70 mRNA expression levels during the II instar larvae was higher in respect to the V instar larvae. A similar difference in mRNA expression levels, but in a less extent, was found for the Hihsp90. Moreover, a diverse transcript level between the two genes at the V larval stage was observed where Hihsp90 was up-regulated compared to Hihsp70. These results suggested the involvement of Hsp70 and Hsp90 in H. illucens development and provide further evidences on the ecological and evolutionary importance of HSPs in the insect developmental processes together with valuable information on molecular features of adaptability to peculiar rearing conditions during food waste bioconversion. Copyright © 2017 Elsevier B.V. All rights reserved.

Selection for high muscle fat in rainbow trout induces potentially higher chylomicron synthesis and PUFA biosynthesis in the intestine.

PubMed

Kamalam, Biju Sam; Panserat, Stephane; Aguirre, Peyo; Geurden, Inge; Fontagné-Dicharry, Stéphanie; Médale, Françoise

2013-02-01

Two lines of rainbow trout divergently selected for muscle fat content, fat line (F) and lean line (L) were used to investigate the effect of genetic selection on digestion, intestinal nutrient transport and fatty acid bioconversion, in relation to dietary starch intake. This study involved a digestibility trial for 2 weeks using Cr(2)O(3) as inert marker, followed by a feeding trial for 4 weeks. For the entire duration, juvenile trout from the two lines were fed diets with or without gelatinized starch. Blood, pyloric ceca, midgut and hindgut were sampled at 24 h after the last meal. Transcripts of the proteins involved in nutrient transport and fatty acid bioconversion were abundant in the proximal intestine. GLUT2 transcripts were slightly higher in the F line ceca than in the L line. Dietary starch intake did not enhance the transcription of intestinal glucose transporters, SGLT1 and GLUT2; but it was associated with the higher expression of ApoA1 and PepT1 in the midgut. Significantly, the F line exhibited higher intestinal mRNA levels of MTP, ApoA4, Elovl2, Elovl5 and D6D than the L line, linked to chylomicron assembly and fatty acid bioconversion. Apparent digestibility coefficients of protein, lipid and starch were high in both lines, but not significantly different between them. In conclusion, we found a higher potential of chylomicron synthesis and fatty acid bioconversion in the intestine of F line, but no adaptive transcriptional response of glucose transporters to dietary starch and no genotypic differences in nutrient digestibility. Copyright © 2012 Elsevier Inc. All rights reserved.

Bioconversion of low quality lignocellulosic agricultural waste into edible protein by Pleurotus sajor-caju (Fr.) Singer

PubMed Central

Mane, Vijay Panjabrao; Patil, Shyam Sopanrao; Syed, Abrar Ahmed; Baig, Mirza Mushtaq Vaseem

2007-01-01

Pleurotus sajor-caju (Fr.) Singer was cultivated on selected agro wastes viz. cotton stalks, groundnut haulms, soybean straw, pigeon pea stalks and leaves and wheat straw, alone or in combinations. Cotton stalks, pigeon pea stalks and wheat straw alone or in combination were found to be more suitable than groundnut haulms and soybean straw for the cultivation. Organic supplements such as groundnut oilseed cake, gram powder and rice bran not only affected growth parameters but also increased yields. Thus bioconversion of lignocellulosic biomass by P. sajor-caju offers a promising way to convert low quality biomass into an improved human food. PMID:17910118

Growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of Lactobacillus upon ultraviolet radiation.

PubMed

Yeo, Siok-Koon; Liong, Min-Tze

2012-11-01

The objective of this study was to evaluate the effects of ultraviolet (UV) radiation (UVB; 90 J/m²) on growth, bioconversion of isoflavones and probiotic properties of parent and subsequent passages of L. casei FTDC 2113. UV radiation significantly enhanced (P < 0.05) the growth of parent cells in mannitol-soymilk fermented at 37°C for 24 h. This had led to an enhanced intracellular and extracellular β-glucosidase activity with a subsequent increase in bioconversion of isoflavones in mannitol-soymilk (P < 0.05). UV radiation also promoted (P < 0.05) the tolerance of parent cells towards acidic condition (pH 2 and 3) and intestinal bile salts (oxgall, taurocholic and cholic acid). In addition, parent treated cells also exhibited better (P < 0.05) adhesion ability to mucin and antimicrobial activity compared to that of the control. All these positive effects of UV radiation were only prevalent in the parent cells without inheritance by first, second and third passage of cells. Although temporary, our results suggested that UV radiation could enhance the bioactive and probiotic potentials of L. casei FTDC 2113, and thus could be applied for the production of probiotic products with enhanced bioactivity.

Fast Microwave-assisted Pretreatment for Bioconversion of Sawdust Lignocellulose to Glucose

NASA Astrophysics Data System (ADS)

Nyoman Sudiana, I.; Mitsudo, Seitaro; Endang Susilowati, Prima; Ketut Sutiari, Desak; Widana Arsana, Made; Zamrun Firihu, Muhammad; Ode Ngkoimani, La; Aba, La; Sahaluddin Hasan, Erzam; Cahyono, Edi; Sabchevski, Svilen; Aripin, Haji; Gde Suastika, Komang

2017-05-01

A preliminary study of application microwave energy for bioconversion of cellulosic sawdust to glucose was performed. The effects of the microwave were compared to those of the conventional method for each solvent. It was expected that a broader mechanism responsible for the microwave effects on the chemical processes, especially the pretreatment on the hydrolysis of cellulose can be explained. Reagents used were an acid (HCl), an alkali (NaOH), and distilled water (H2O). The experimental results showed that the microwave-assisted pretreatment on the lignocellulosic sawdust faster than by using conventional heating (hotplate). Moreover by using microwave a higher glucose content compared to the conventional method was found. With microwave during hydrolisis, high temperatures and high reagent concentrations were not required. Pretreatment with a microwave at 800 Watt and solvent NaOH 22,50 mg/mL at a temperature of 120°c appeared to be most efficient found in this experiment. These results indicate that microwave effective for bioconversion of cellulosic sawdust to glucose. The microstructure evaluation by using SEM and XRD should be performed to understand more detail the effect especially on their cellulosic structural evolution.

Biofilm reactors for industrial bioconversion processes: employing potential of enhanced reaction rates

PubMed Central

Qureshi, Nasib; Annous, Bassam A; Ezeji, Thaddeus C; Karcher, Patrick; Maddox, Ian S

2005-01-01

This article describes the use of biofilm reactors for the production of various chemicals by fermentation and wastewater treatment. Biofilm formation is a natural process where microbial cells attach to the support (adsorbent) or form flocs/aggregates (also called granules) without use of chemicals and form thick layers of cells known as "biofilms." As a result of biofilm formation, cell densities in the reactor increase and cell concentrations as high as 74 gL-1 can be achieved. The reactor configurations can be as simple as a batch reactor, continuous stirred tank reactor (CSTR), packed bed reactor (PBR), fluidized bed reactor (FBR), airlift reactor (ALR), upflow anaerobic sludge blanket (UASB) reactor, or any other suitable configuration. In UASB granular biofilm particles are used. This article demonstrates that reactor productivities in these reactors have been superior to any other reactor types. This article describes production of ethanol, butanol, lactic acid, acetic acid/vinegar, succinic acid, and fumaric acid in addition to wastewater treatment in the biofilm reactors. As the title suggests, biofilm reactors have high potential to be employed in biotechnology/bioconversion industry for viable economic reasons. In this article, various reactor types have been compared for the above bioconversion processes. PMID:16122390

Grass Lignocellulose

NASA Astrophysics Data System (ADS)

Akin, Danny E.

Grass lignocelluloses are limited in bioconversion by aromatic constituents, which include both lignins and phenolic acids esters. Histochemistry, ultraviolet absorption microspectrophotometry, and response to microorganisms and specific enzymes have been used to determine the significance of aromatics toward recalcitrance. Coniferyl lignin appears to be the most effective limitation to biodegradation, existing in xylem cells of vascular tissues; cell walls with syringyl lignin, for example, leaf sclerenchyma, are less recalcitrant. Esterified phenolic acids, i.e., ferulic and p-coumaric acids, often constitute a major chemical limitation in nonlignified cell walls to biodegradation in grasses, especially warm-season species. Methods to improve biodegradability through modification of aromatics include: plant breeding, use of lignin-degrading white-rot fungi, and addition of esterases. Plant breeding for new cultivars has been especially effective for nutritionally improved forages, for example, bermudagrasses. In laboratory studies, selective white-rot fungi that lack cellulases delignified the lignocellulosic materials and improved fermentation of residual carbohydrates. Phenolic acid esterases released p-coumaric and ferulic acids for potential coproducts, improved the available sugars for fermentation, and improved biodegradation. The separation and removal of the aromatic components for coproducts, while enhancing the availability of sugars for bioconversion, could improve the economics of bioconversion.

Metabolic pathway reconstruction of eugenol to vanillin bioconversion in Aspergillus niger

PubMed Central

Srivastava, Suchita; Luqman, Suaib; Khan, Feroz; Chanotiya, Chandan S; Darokar, Mahendra P

2010-01-01

Identification of missing genes or proteins participating in the metabolic pathways as enzymes are of great interest. One such class of pathway is involved in the eugenol to vanillin bioconversion. Our goal is to develop an integral approach for identifying the topology of a reference or known pathway in other organism. We successfully identify the missing enzymes and then reconstruct the vanillin biosynthetic pathway in Aspergillus niger. The procedure combines enzyme sequence similarity searched through BLAST homology search and orthologs detection through COG & KEGG databases. Conservation of protein domains and motifs was searched through CDD, PFAM & PROSITE databases. Predictions regarding how proteins act in pathway were validated experimentally and also compared with reported data. The bioconversion of vanillin was screened on UV-TLC plates and later confirmed through GC and GC-MS techniques. We applied a procedure for identifying missing enzymes on the basis of conserved functional motifs and later reconstruct the metabolic pathway in target organism. Using the vanillin biosynthetic pathway of Pseudomonas fluorescens as a case study, we indicate how this approach can be used to reconstruct the reference pathway in A. niger and later results were experimentally validated through chromatography and spectroscopy techniques. PMID:20978605

Enantioselectivity of the bioconversion of chiral citronellal during the inhibition of wheat seeds germination.

PubMed

Cavalieri, Andrea; Fischer, Ravit; Larkov, Olga; Dudai, Nativ

2014-03-01

Citronellal is one of the most prominent monoterpenes present in many essential oils. Low persistence of essential oils as bioherbicides has often been addressed because of the high volatility of these compounds. Bioconversion of citronellal by wheat seeds releases less aggressive and injurious compounds as demonstrated by their diminished germination. We demonstrated that optically pure citronellal enantiomers were reduced to optically pure citronellol enantiomers with retention of the configuration both in isolated wheat embryos and endosperms. Our findings reveal the potential of essential oils as allelopathic agents providing an insight into their mechanism of action and persistence. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

Enhanced biocatalytic production of L-cysteine by Pseudomonas sp. B-3 with in situ product removal using ion-exchange resin.

PubMed

Wang, Pu; He, Jun-Yao; Yin, Jiang-Feng

2015-03-01

Bioconversion of DL-2-amino-Δ(2)-thiazoline-4-carboxylic acid (DL-ATC) catalyzed by whole cells of Pseudomonas sp. was successfully applied for the production of L-cysteine. It was found, however, like most whole-cell biocatalytic processes, the accumulated L-cysteine produced obvious inhibition to the activity of biocatalyst and reduced the yield. To improve L-cysteine productivity, an anion exchange-based in situ product removal (ISPR) approach was developed. Several anion-exchange resins were tested to select a suitable adsorbent used in the bioconversion of DL-ATC for the in situ removal of L-cysteine. The strong basic anion-exchange resin 201 × 7 exhibited the highest adsorption capacity for L-cysteine and low adsorption for DL-ATC, which is a favorable option. With in situ addition of 60 g L(-1) resin 201 × 7, the product inhibition can be reduced significantly and 200 mmol L(-1) of DL-ATC was converted to L-cysteine with 90.4 % of yield and 28.6 mmol L(-1 )h(-1) of volumetric productivity. Compared to the bioconversion without the addition of resin, the volumetric productivity of L-cysteine was improved by 2.27-fold using ISPR method.

Novel Halomonas sp. B15 isolated from Larnaca Salt Lake in Cyprus that generates vanillin and vanillic acid from ferulic acid.

PubMed

Vyrides, Ioannis; Agathangelou, Maria; Dimitriou, Rodothea; Souroullas, Konstantinos; Salamex, Anastasia; Ioannou, Aristostodimos; Koutinas, Michalis

2015-08-01

Vanillin is a high value added product with many applications in the food, fragrance and pharmaceutical industries. A natural and low-cost method to produce vanillin is by microbial bioconversions through ferulic acid. Until now, limited microorganisms have been found capable of bioconverting ferulic acid to vanillin at high yield. This study aimed to screen halotolerant strains of bacteria from Larnaca Salt Lake which generate vanillin and vanillic acid from ferulic acid. From a total of 50 halotolenant/halophilic strains 8 grew in 1 g/L ferulic acid and only 1 Halomonas sp. B15 and 3 Halomonas elognata strains were capable of bioconverting ferulic acid to vanillic acid at 100 g NaCl/L. The highest vanillic acid (365 mg/L) at these conditions generated by Halomonas sp. B15 which corresponds to ferulic acid bioconversion yield of 36.5%. Using the resting cell technique with an initial ferulic acid concentration of 0.5 g/L at low salinity, the highest production of vanillin (245 mg/L) took place after 48 h, corresponding to a bioconversion yield of 49%. This is the first reported Halomonas sp. with high yield of vanillin production from ferulic acid at low salinity.

Bioconversion of Sugarcane Biomass into Ethanol: An Overview about Composition, Pretreatment Methods, Detoxification of Hydrolysates, Enzymatic Saccharification, and Ethanol Fermentation

PubMed Central

Canilha, Larissa; Chandel, Anuj Kumar; Suzane dos Santos Milessi, Thais; Antunes, Felipe Antônio Fernandes; Luiz da Costa Freitas, Wagner; das Graças Almeida Felipe, Maria; da Silva, Silvio Silvério

2012-01-01

Depleted supplies of fossil fuel, regular price hikes of gasoline, and environmental damage have necessitated the search for economic and eco-benign alternative of gasoline. Ethanol is produced from food/feed-based substrates (grains, sugars, and molasses), and its application as an energy source does not seem fit for long term due to the increasing fuel, food, feed, and other needs. These concerns have enforced to explore the alternative means of cost competitive and sustainable supply of biofuel. Sugarcane residues, sugarcane bagasse (SB), and straw (SS) could be the ideal feedstock for the second-generation (2G) ethanol production. These raw materials are rich in carbohydrates and renewable and do not compete with food/feed demands. However, the efficient bioconversion of SB/SS (efficient pretreatment technology, depolymerization of cellulose, and fermentation of released sugars) remains challenging to commercialize the cellulosic ethanol. Among the technological challenges, robust pretreatment and development of efficient bioconversion process (implicating suitable ethanol producing strains converting pentose and hexose sugars) have a key role to play. This paper aims to review the compositional profile of SB and SS, pretreatment methods of cane biomass, detoxification methods for the purification of hydrolysates, enzymatic hydrolysis, and the fermentation of released sugars for ethanol production. PMID:23251086

[Phase transfer catalyzed bioconversion of penicillin G to 6-APA by immobilized penicillin acylase in recyclable aqueous two-phase systems with light/pH sensitive copolymers].

PubMed

Jin, Ke-ming; Cao, Xue-jun; Su, Jin; Ma, Li; Zhuang, Ying-ping; Chu, Ju; Zhang, Si-liang

2008-03-01

Immobilized penicillin acylase was used for bioconversion of penicillin PG into 6-APA in aqueous two-phase systems consisting of a light-sensitive polymer PNBC and a pH-sensitive polymer PADB. Partition coefficients of 6-APA was found to be about 5.78 in the presence of 1% NaCl. Enzyme kinetics showed that the reaction reached equilibrium at roughly 7 h. The 6-APA mole yields were 85.3% (pH 7.8, 20 degrees C), with about 20% increment as compared with the reaction of single aqueous phase buffer. The partition coefficient of PG (Na) varied scarcely, while that of the product, 6-APA and phenylacetic acid (PA) significantly varied due to Donnan effect of the phase systems and hydrophobicity of the products. The variation of the partition coefficients of the products also affected the bioconversion yield of the products. In the aqueous two-phase systems, the substrate, PG, the products of 6-APA and PA were biased in the top phase, while immobilized penicillin acylase at completely partitioned at the bottom. The substrate and PG entered the bottom phase, where it was catalyzed into 6-APA and PA and entered the top phase. Inhibition of the substrate and products was removed to result in improvement of the product yield, and the immobilized enzyme showed higher efficiency than the immobilized cells and occupied smaller volume. Compared with the free enzyme, immobilized enzyme had greater stability, longer life-time, and was completely partitioned in the bottom phase and recycle. Bioconversion in two-phase systems using immobilized penicillin acylase showed outstanding advantage. The light-sensitive copolymer forming aqueous two-phase systems could be recovered by laser radiation at 488 nm or filtered 450 nm light, while pH-sensitive polymer PADB could be recovered at the isoelectric point (pH 4.1). The recovery of the two copolymers was between 95% and 99%.

Temperature Increase Negatively Affects the Fatty Acid Bioconversion Capacity of Rainbow Trout (Oncorhynchus mykiss) Fed a Linseed Oil-Based Diet

PubMed Central

Mellery, Julie; Geay, Florian; Tocher, Douglas R.; Kestemont, Patrick; Debier, Cathy; Rollin, Xavier; Larondelle, Yvan

2016-01-01

Aquaculture is meant to provide fish rich in omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA). This objective must be reached despite (1) the necessity to replace the finite and limited fish oil in feed production and (2) the increased temperature of the supply water induced by the global warming. The objective of the present paper was to determine to what extent increased water temperature influences the fatty acid bioconversion capacity of rainbow trout (Oncorhynchus mykiss) fed a plant-derived diet. Fish were fed two diets formulated with fish oil (FO) or linseed oil (LO) as only added lipid source at the optimal water temperature of 15°C or at the increased water temperature of 19°C for 60 days. We observed that a temperature increase close to the upper limit of the species temperature tolerance range negatively affected the feed efficiency of rainbow trout fed LO despite a higher feed intake. The negative impact of increased water temperature on fatty acid bioconversion capacity appeared also to be quite clear considering the reduced expression of fatty acid desaturase 2 in liver and intestine and the reduced Δ6 desaturase enzymatic activity in intestinal microsomes. The present results also highlighted a negative impact of increased temperature on the apparent in vivo enzymatic activity of Δ5 and Δ6 desaturases of fish fed LO. Interestingly, this last parameter appeared less affected than those mentioned above. This study highlights that the increased temperature that rainbow trout may face due to global warming could reduce their fatty acid bioconversion capacity. The unavoidable replacement of finite fish oil by more sustainable, readily available and economically viable alternative lipid sources in aquaculture feeds should take this undeniable environmental issue on aquaculture productivity into account. PMID:27736913

A Two-Step Bioconversion Process for Canolol Production from Rapeseed Meal Combining an Aspergillus niger Feruloyl Esterase and the Fungus Neolentinus lepideus

PubMed Central

Odinot, Elise; Fine, Frédéric; Sigoillot, Jean-Claude; Navarro, David; Laguna, Oscar; Bisotto, Alexandra; Peyronnet, Corinne; Lecomte, Jérôme; Faulds, Craig B.

2017-01-01

Rapeseed meal is a cheap and abundant raw material, particularly rich in phenolic compounds of biotechnological interest. In this study, we developed a two-step bioconversion process of naturally occurring sinapic acid (4-hydroxy-3,5-dimethoxycinnamic acid) from rapeseed meal into canolol by combining the complementary potentialities of two filamentous fungi, the micromycete Aspergillus niger and the basidiomycete Neolentinus lepideus. Canolol could display numerous industrial applications because of its high antioxidant, antimutagenic and anticarcinogenic properties. In the first step of the process, the use of the enzyme feruloyl esterase type-A (named AnFaeA) produced with the recombinant strain A. niger BRFM451 made it possible to release free sinapic acid from the raw meal by hydrolysing the conjugated forms of sinapic acid in the meal (mainly sinapine and glucopyranosyl sinapate). An amount of 39 nkat AnFaeA per gram of raw meal, at 55 °C and pH 5, led to the recovery of 6.6 to 7.4 mg of free sinapic acid per gram raw meal, which corresponded to a global hydrolysis yield of 68 to 76% and a 100% hydrolysis of sinapine. Then, the XAD2 adsorbent (a styrene and divinylbenzene copolymer resin), used at pH 4, enabled the efficient recovery of the released sinapic acid, and its concentration after elution with ethanol. In the second step, 3-day-old submerged cultures of the strain N. lepideus BRFM15 were supplied with the recovered sinapic acid as the substrate of bioconversion into canolol by a non-oxidative decarboxylation pathway. Canolol production reached 1.3 g/L with a molar yield of bioconversion of 80% and a productivity of 100 mg/L day. The same XAD2 resin, when used at pH 7, allowed the recovery and purification of canolol from the culture broth of N. lepideus. The two-step process used mild conditions compatible with green chemistry. PMID:29036919

Temperature Increase Negatively Affects the Fatty Acid Bioconversion Capacity of Rainbow Trout (Oncorhynchus mykiss) Fed a Linseed Oil-Based Diet.

PubMed

Mellery, Julie; Geay, Florian; Tocher, Douglas R; Kestemont, Patrick; Debier, Cathy; Rollin, Xavier; Larondelle, Yvan

2016-01-01

Aquaculture is meant to provide fish rich in omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFA). This objective must be reached despite (1) the necessity to replace the finite and limited fish oil in feed production and (2) the increased temperature of the supply water induced by the global warming. The objective of the present paper was to determine to what extent increased water temperature influences the fatty acid bioconversion capacity of rainbow trout (Oncorhynchus mykiss) fed a plant-derived diet. Fish were fed two diets formulated with fish oil (FO) or linseed oil (LO) as only added lipid source at the optimal water temperature of 15°C or at the increased water temperature of 19°C for 60 days. We observed that a temperature increase close to the upper limit of the species temperature tolerance range negatively affected the feed efficiency of rainbow trout fed LO despite a higher feed intake. The negative impact of increased water temperature on fatty acid bioconversion capacity appeared also to be quite clear considering the reduced expression of fatty acid desaturase 2 in liver and intestine and the reduced Δ6 desaturase enzymatic activity in intestinal microsomes. The present results also highlighted a negative impact of increased temperature on the apparent in vivo enzymatic activity of Δ5 and Δ6 desaturases of fish fed LO. Interestingly, this last parameter appeared less affected than those mentioned above. This study highlights that the increased temperature that rainbow trout may face due to global warming could reduce their fatty acid bioconversion capacity. The unavoidable replacement of finite fish oil by more sustainable, readily available and economically viable alternative lipid sources in aquaculture feeds should take this undeniable environmental issue on aquaculture productivity into account.

Sulfur deficiency changes mycosporine-like amino acid (MAA) composition of Anabaena variabilis PCC 7937: a possible role of sulfur in MAA bioconversion.

PubMed

Singh, Shailendra P; Klisch, Manfred; Sinha, Rajeshwar P; Häder, Donat-Peter

2010-01-01

In the present investigation we show for the first time that bioconversion of a primary mycosporine-like amino acid (MAA) into a secondary MAA is regulated by sulfur deficiency in the cyanobacterium Anabaena variabilis PCC 7937. This cyanobacterium synthesizes the primary MAA shinorine (RT = 2.2 min, lambda(max) = 334 nm) under normal conditions (PAR + UV-A + UV-B); however, under sulfur deficiency, a secondary MAA palythine-serine (RT = 3.9 min, lambda(max) = 320 nm) appears. Addition of methionine to sulfur-deficient cultures resulted in the disappearance of palythine-serine, suggesting the role of primary MAAs under sulfur deficiency in recycling of methionine by donating the methyl group from the glycine subunit of shinorine to tetrahydrofolate to regenerate the methionine from homocysteine. This is also the first report for the synthesis of palythine-serine by cyanobacteria which has so far been reported only from corals. Addition of methionine also affected the conversion of mycosporine-glycine into shinorine, consequently, resulted in the appearance of mycosporine-glycine (RT = 3.6 min, lambda(max) = 310 nm). Our results also suggest that palythine-serine is synthesized from shinorine. Based on these results we propose that glycine decarboxylase is the potential enzyme that catalyzes the bioconversion of shinorine to palythine-serine by decarboxylation and demethylation of the glycine unit of shinorine.

Analysis, pretreatment and enzymatic saccharification of different fractions of Scots pine.

PubMed

Normark, Monica; Winestrand, Sandra; Lestander, Torbjörn A; Jönsson, Leif J

2014-03-19

Forestry residues consisting of softwood are a major lignocellulosic resource for production of liquid biofuels. Scots pine, a commercially important forest tree, was fractionated into seven fractions of chips: juvenile heartwood, mature heartwood, juvenile sapwood, mature sapwood, bark, top parts, and knotwood. The different fractions were characterized analytically with regard to chemical composition and susceptibility to dilute-acid pretreatment and enzymatic saccharification. All fractions were characterized by a high glucan content (38-43%) and a high content of other carbohydrates (11-14% mannan, 2-4% galactan) that generate easily convertible hexose sugars, and by a low content of inorganic material (0.2-0.9% ash). The lignin content was relatively uniform (27-32%) and the syringyl-guaiacyl ratio of the different fractions were within the range 0.021-0.025. The knotwood had a high content of extractives (9%) compared to the other fractions. The effects of pretreatment and enzymatic saccharification were relatively similar, but without pretreatment the bark fraction was considerably more susceptible to enzymatic saccharification. Since sawn timber is a main product from softwood species such as Scots pine, it is an important issue whether different parts of the tree are equally suitable for bioconversion processes. The investigation shows that bioconversion of Scots pine is facilitated by that most of the different fractions exhibit relatively similar properties with regard to chemical composition and susceptibility to techniques used for bioconversion of woody biomass.

Bioconversion of Airborne Methylamine by Immobilized Recombinant Amine Oxidase from the Thermotolerant Yeast Hansenula polymorpha

PubMed Central

Sigawi, Sasi; Nitzan, Yeshayahu

2014-01-01

Aliphatic amines, including methylamine, are air-pollutants, due to their intensive use in industry and the natural degradation of proteins, amino acids, and other nitrogen-containing compounds in biological samples. It is necessary to develop systems for removal of methylamine from the air, since airborne methylamine has a negative effect on human health. The primary amine oxidase (primary amine : oxygen oxidoreductase (deaminating) or amine oxidase, AMO; EC 1.4.3.21), a copper-containing enzyme from the thermotolerant yeast Hansenula polymorpha which was overexpressed in baker's yeast Saccharomyces cerevisiae, was tested for its ability to oxidize airborne methylamine. A continuous fluidized bed bioreactor (CFBR) was designed to enable bioconversion of airborne methylamine by AMO immobilized in calcium alginate (CA) beads. The results demonstrated that the bioreactor with immobilized AMO eliminates nearly 97% of the airborne methylamine. However, the enzymatic activity of AMO causes formation of formaldehyde. A two-step bioconversion process was therefore proposed. In the first step, airborne methylamine was fed into a CFBR which contained immobilized AMO. In the second step, the gas flow was passed through another CFBR, with alcohol oxidase from the yeast H. polymorpha immobilized in CA, in order to decompose the formaldehyde formed in the first step. The proposed system provided almost total elimination of the airborne methylamine and the formaldehyde. PMID:24672387

Direct conversion of starch to ethanol using recombınant Saccharomyces cerevisiae containing glucoamylase gene

NASA Astrophysics Data System (ADS)

Purkan, P.; Baktir, A.; Puspaningsih, N. N. T.; Ni'mah, M.

2017-09-01

Saccharomyces cerevisiae is known for its high fermentative capacity, high ethanol yield and its high ethanol tolerance. The yeast is inability converting starch (relatively inexpensive substrate) into biofuel ethanol. Insertion of glucoamylase gene in yeast cell of Saccharomyces cerevisiae had been done to increase the yeast function in ethanol fermentation from starch. Transformation of yeast of S. cerevisiae with recombinant plasmid yEP-GLO1 carrying gene encoding glucoamylase (GLO1) produced the recombinant yeast which enable to degrade starch. Optimizing of bioconversion process of starch into ethanol by the yeast of recombinant Saccharomyces cerevisiae [yEP-GLO1] had been also done. Starch concentration which could be digested by recombinant yeast of S. cerevisiae [yEP-GLO1] was 10% (w/v). Bioconversion of starch having concentration 10% (b/v) using recombinant yeast of S. cerevisiae BY5207 [yEP-GLO1] could result ethanol as 20% (v/v) to alcoholmeter and 19,5% (v/v) to gas of chromatography. Otherwise, using recombinant yeast S. cerevisiae S. cerevisiae AS3324 [yEP-GLO1] resulted ethanol as 17% (v/v) to alcoholmeter and 17,5% (v/v) to gas of chromatography. The highest ethanol in starch bioconversion using both recombinant yeasts BY5207 and AS3324 could be resulted on 144 hours of fermentation time as well as in pH 5.

[Organic waste treatment by earthworm vermicomposting and larvae bioconversion: review and perspective].

PubMed

Zhang, Zhi-jian; Liu, Meng; Zhu, Jun

2013-05-01

There is a growing attention on the environmental pollution and loss of potential regeneration of resources due to the poor handling of organic wastes, while earthworm vermicomposting and larvae bioconversion are well-known as two promising biotechnologies for sustainable wastes treatments, where earthworms or housefly larvae are employed to convert the organic wastes into humus like material, together with value-added worm product. Taken earthworm ( Eisenia foetida) and housefly larvae ( Musca domestica) as model species, this work illustrates fundamental definition and principle, operational process, technical mechanism, main factors, and bio-chemical features of organisms of these two technologies. Integrated with the physical and biochemical mechanisms, processes of biomass conversion, intestinal digestion, enzyme degradation and microflora decomposition are comprehensively reviewed on waste treatments with purposes of waste reduction, value-addition, and stabilization.

Nitrile bioconversion by Microbacterium imperiale CBS 498-74 resting cells in batch and ultrafiltration membrane bioreactors.

PubMed

Cantarella, M; Cantarella, L; Gallifuoco, A; Spera, A

2006-03-01

The biohydration of acrylonitrile, propionitrile and benzonitrile catalysed by the NHase activity contained in resting cells of Microbacterium imperiale CBS 498-74 was operated at 5, 10 and 20 degrees C in laboratory-scale batch and membrane bioreactors. The bioreactions were conducted in buffered medium (50 mM Na(2)HPO(4)/NaH(2)PO(4), pH 7.0) in the presence of distilled water or tap-water, to simulate a possible end-pipe biotreatment process. The integral bioreactor performances were studied with a cell loading (dry cell weight; DCW) varying from 0.1 mg(DCW) per reactor to 16 mg(DCW) per reactor, in order to realize near 100% bioconversion of acrylonitrile, propionitrile and benzonitrile without consistent loss of NHase activity.

Effects of moisture content of food waste on residue separation, larval growth and larval survival in black soldier fly bioconversion.

PubMed

Cheng, Jack Y K; Chiu, Sam L H; Lo, Irene M C

2017-09-01

In order to foster sustainable management of food waste, innovations in food waste valorization technologies are crucial. Black soldier fly (BSF) bioconversion is an emerging technology that can turn food waste into high-protein fish feed through the use of BSF larvae. The conventional method of BSF bioconversion is to feed BSF larvae with food waste directly without any moisture adjustment. However, it was reported that difficulty has been experienced in the separation of the residue (larval excreta and undigested material) from the insect biomass due to excessive moisture. In addition to the residue separation problem, the moisture content of the food waste may also affect the growth and survival aspects of BSF larvae. This study aims to determine the most suitable moisture content of food waste that can improve residue separation as well as evaluate the effects of the moisture content of food waste on larval growth and survival. In this study, pre-consumer and post-consumer food waste with different moisture content (70%, 75% and 80%) was fed to BSF larvae in a temperature-controlled rotary drum reactor. The results show that the residue can be effectively separated from the insect biomass by sieving using a 2.36mm sieve, for both types of food waste at 70% and 75% moisture content. However, sieving of the residue was not feasible for food waste at 80% moisture content. On the other hand, reduced moisture content of food waste was found to slow down larval growth. Hence, there is a trade-off between the sieving efficiency of the residue and the larval growth rate. Furthermore, the larval survival rate was not affected by the moisture content of food waste. A high larval survival rate of at least 95% was achieved using a temperature-controlled rotary drum reactor for all treatment groups. The study provides valuable insights for the waste management industry on understanding the effects of moisture content when employing BSF bioconversion for food waste recycling. Copyright © 2017 Elsevier Ltd. All rights reserved.

evaluation of the bioconversion of genetically modified switchgrass using simultaneous saccharification and fermentation ans a consolidated bioprocessing approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yee, Kelsey L; Rodriguez, Jr., Miguel; Tschaplinski, Timothy J

2012-01-01

Abstract Background: The inherent recalcitrance of lignocellulosic biomass is one of the major economic hurdles for the production of fuels and chemicals from biomass. Additionally, lignin is recognized as having a negative impact on enzymatic hydrolysis of biomass, and as a result much interest has been placed on modifying the lignin pathway to improve bioconversion of lignocellulosic feedstocks. Results: Previous results showed down-regulation of the caffeic acid 3-O-methyl transferase (COMT) gene in the lignin pathway yielded switchgrass (Panicum virgatum) that was more susceptible to bioconversion after dilute acid pretreatment. Here we examined the response of these plant lines to mildermore » pretreatment conditions with yeast-based SSF, CBP with Clostridium thermocellum, and fermentations with the cellulolytic extreme thermophiles, Caldicellulosiruptor bescii and Caldicellulosiruptor obsidiansis. Unlike the S. cerevisiae SSF conversions, fermentations of pretreated down-regulated COMT transgenic switchgrass with C. thermocellum showed an apparent inhibition of fermentation not observed in the wild-type switchgrass. This inhibition can be eliminated by hot water extraction of the pretreated biomass which resulted in superior conversion yield with transgenic versus wild-type switchgrass for C. thermocellum, also exceeding the yeast-based SSF yield. Further fermentation evaluation of the transgenic switchgrass indicated differential inhibition for the Caldicellulosiruptor strains, which could not be rectified by additional processing conditions. Gas chromatography-mass spectrometry metabolite profiling was used to examine the fermentation broth to elucidate the relative abundance of lignin derived aromatic compounds. The types and abundance of fermentation-derived lignin constituents varied between C. thermocellum and each of the Caldicellulosiruptor strains. Conclusions: The down-regulation of the COMT gene improves the bioconversion of switchgrass relative to the wild-type regardless of the pretreatment condition or fermentation microorganism. However, bacterial fermentations demonstrated strain-dependent sensitivity to the COMT transgenic biomass, likely due to additional soluble lignin pathway-derived constituents resulting from the COMT gene disruption. Removal of these inhibitory constituents permitted completion of fermentation by C. thermocellum, but not by the Caldicellulosiruptor strains. The reason for this difference needs to be explored further.« less

Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Yanna

To increase our understanding of coal biogasification and move this technology closer toward field scale demonstration, we have thoroughly investigated coal bioconversion both ex situ and in situ. Specifically, we have screened a total of 12 parameters and identified those that exert statistically positive influence on coal biogasification. Based on these evaluations, a recipe for a nutrient solution was developed. With the addition of this nutrient solution, methane yield from Illinois coal was enhanced dramatically. In addition, we have demonstrated that coal bioconversion can be sustained over a long period of time as long as suitable conditions were maintained. Furthermore,more » biogasification of coal was tested under pressure simulating in situ conditions. Surprisingly, pressure was found to have no negative effects on microbial activities. Thus, the same recipe developed for ex situ may be used in situ as well.« less

Characterization of hydrocortisone bioconversion and 16S RNA gene in Synechococcus nidulans cultures.

PubMed

Rasoul-Amini, S; Ghasemi, Y; Morowvat, M H; Ghoshoon, M B; Raee, M J; Mosavi-Azam, S B; Montazeri-Najafabady, N; Nouri, F; Parvizi, R; Negintaji, N; Khoubani, S

2010-01-01

A unicellular cyanobacterium, Synechococcus nidulans (Pringsheim) Komárek, was isolated from paddy-fields and applied in the biotransformation experiment of hydrocortisone (1). This strain has not been previously tested for steroid bioconversion. Fermentation was carried out in BG-11 medium supplemented with 0.05% substrate at 25 degrees C for 14 days of incubation. The obtained products were chromatographically purified followed by their characterization using spectroscopic methods. 11beta,17beta-dihydroxyandrost-4-en-3-one (2), 11beta-hydroxyandrost-4-en-3,17-dione (3), and androst-4-ene-3,17-dione (4) were the main bioproducts in the hydrocortisone bioconversion. The observed bioreaction characteristics were the side chain degradation of the substrate to prepare compounds (2) and (3) following the 11beta-dehydroxylation for accumulation of the compound (4). Time course study showed the accumulation of the product (2) from the second day of the fermentation and compounds (3) and (4) from the third day. All the metabolites reached their maximum concentration in seven days. Cyanobacterial 16S rRNA gene was also amplified by PCR. Sequences were amplified using the universal prokaryotic primers which amplify a approximately 400-bp region of the 16S rRNA gene. PCR products were sequenced to confirm their authenticity as 16S rRNA gene of cyanobacteria. The result of PCR blasted with other sequenced cyanobacteria in NCBI showed 99% identity to the 16S small subunit rRNA of seven Synechococcus species.

Analysis, pretreatment and enzymatic saccharification of different fractions of Scots pine

PubMed Central

2014-01-01

Background Forestry residues consisting of softwood are a major lignocellulosic resource for production of liquid biofuels. Scots pine, a commercially important forest tree, was fractionated into seven fractions of chips: juvenile heartwood, mature heartwood, juvenile sapwood, mature sapwood, bark, top parts, and knotwood. The different fractions were characterized analytically with regard to chemical composition and susceptibility to dilute-acid pretreatment and enzymatic saccharification. Results All fractions were characterized by a high glucan content (38-43%) and a high content of other carbohydrates (11-14% mannan, 2-4% galactan) that generate easily convertible hexose sugars, and by a low content of inorganic material (0.2-0.9% ash). The lignin content was relatively uniform (27-32%) and the syringyl-guaiacyl ratio of the different fractions were within the range 0.021-0.025. The knotwood had a high content of extractives (9%) compared to the other fractions. The effects of pretreatment and enzymatic saccharification were relatively similar, but without pretreatment the bark fraction was considerably more susceptible to enzymatic saccharification. Conclusions Since sawn timber is a main product from softwood species such as Scots pine, it is an important issue whether different parts of the tree are equally suitable for bioconversion processes. The investigation shows that bioconversion of Scots pine is facilitated by that most of the different fractions exhibit relatively similar properties with regard to chemical composition and susceptibility to techniques used for bioconversion of woody biomass. PMID:24641769

Directed evolution of toluene dioxygenase from Pseudomonas putida for improved selectivity toward cis-indandiol during indene bioconversion.

PubMed

Zhang, N; Stewart, B G; Moore, J C; Greasham, R L; Robinson, D K; Buckland, B C; Lee, C

2000-10-01

Toluene dioxygenase (TDO) from Pseudomonas putida F1 converts indene to a mixture of cis-indandiol (racemic), 1-indenol, and 1-indanone. The desired product, cis-(1S,2R)-indandiol, is a potential key intermediate in the chemical synthesis of indinavir sulfate (Crixivan), Merck's HIV-1 protease inhibitor for the treatment of AIDS. To reduce the undesirable byproducts 1-indenol and 1-indanone formed during indene bioconversion, the recombinant TDO expressed in Escherichia coli was evolved by directed evolution using the error-prone polymerase chain reaction (epPCR) method. High-throughput fluorometric and spectrophotometric assays were developed for rapid screening of the mutant libraries in a 96-well format. Mutants with reduced 1-indenol by-product formation were identified, and the individual indene bioconversion product profiles of the selected mutants were confirmed by HPLC. Changes in the amino acid sequence of the mutant enzymes were identified by analyzing the nucleotide sequence of the genes. A mutant with the most desirable product profile from each library, defined as the most reduced 1-indenol concentration and with the highest cis-(1S,2R)-indandiol enantiomeric excess, was used to perform each subsequent round of mutagenesis. After three rounds of mutagenesis and screening, mutant 1C4-3G was identified to have a threefold reduction in 1-indenol formation over the wild type (20% vs 60% of total products) and a 40% increase of product (cis-indandiol) yield.

Microplate-Based Evaluation of the Sugar Yield from Giant Reed, Giant Miscanthus and Switchgrass after Mild Chemical Pre-Treatments and Hydrolysis with Tailored Trichoderma Enzymatic Blends.

PubMed

Cianchetta, Stefano; Bregoli, Luca; Galletti, Stefania

2017-11-01

Giant reed, miscanthus, and switchgrass are considered prominent lignocellulosic feedstocks to obtain fermentable sugars for biofuel production. The bioconversion into sugars requires a delignifying pre-treatment step followed by hydrolysis with cellulase and other accessory enzymes like xylanase, especially in the case of alkali pre-treatments, which retain the hemicellulose fraction. Blends richer in accessory enzymes than commercial mix can be obtained growing fungi on feedstock-based substrates, thus ten selected Trichoderma isolates, including the hypercellulolytic strain Trichoderma reesei Rut-C30, were grown on giant reed, miscanthus, or switchgrass-based substrates. The produced enzymes were used to saccharify the corresponding feedstocks, compared to a commercial enzymatic mix (6 FPU/g). Feedstocks were acid (H 2 SO 4 0.2-2%, w/v) or alkali (NaOH 0.02-0.2%, w/v) pre-treated. A microplate-based approach was chosen for most of the experimental steps due to the large number of samples. The highest bioconversion was generally obtained with Trichoderma harzianum Or4/99 enzymes (78, 89, and 94% final sugar yields at 48 h for giant reed, miscanthus, and switchgrass, respectively), with significant increases compared to the commercial mix, especially with alkaline pre-treatments. The differences in bioconversion yields were only partially caused by xylanases (maximum R 2  = 0.5), indicating a role for other accessory enzymes.

Largely enhanced bioethanol production through the combined use of lignin-modified sugarcane and xylose fermenting yeast strain.

PubMed

Ko, Ja Kyong; Jung, Je Hyeong; Altpeter, Fredy; Kannan, Baskaran; Kim, Ha Eun; Kim, Kyoung Heon; Alper, Hal S; Um, Youngsoon; Lee, Sun-Mi

2018-05-01

The recalcitrant structure of lignocellulosic biomass is a major barrier in efficient biomass-to-ethanol bioconversion processes. The combination of feedstock engineering via modification in the lignin synthesis pathway of sugarcane and co-fermentation of xylose and glucose with a recombinant xylose utilizing yeast strain produced 148% more ethanol compared to that of the wild type biomass and control strain. The lignin reduced biomass led to a substantially increased release of fermentable sugars (glucose and xylose). The engineered yeast strain efficiently co-utilized glucose and xylose for fermentation, elevating ethanol yields. In this study, it was experimentally demonstrated that the combined efforts of engineering both feedstock and microorganisms largely enhances the bioconversion of lignocellulosic feedstock to bioethanol. This strategy will significantly improve the economic feasibility of lignocellulosic biofuels production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Integrated waste management for rural development in Egypt.

PubMed

Shehata, S M; El Shimi, S A; Elkattan, M H; Ali, B E; El-Housseini, M; El Sayad, S A; Mahmoud, M S; Zaki, A M; Hamdi, Y A; El-Nawawy, A S

2004-01-01

Rural areas generate a large amount of plant and animal residues that can be recycled and utilized instead of relocation and/or burning. This will lead to increasing the benefits from agricultural sector in rural communities and ensuring a better environment. To increase the economic output and environmental benefits of recycling agricultural residues, integrated system should be considered, e.g., energy--compost-recycled water system; composting--co-composting system; food-feed compost system, ensilage of crop residues. The present work was a pilot study for optimizing integrated systems for bioconversion agricultural residues completed by establishing a Training Center for Recycling Agricultural Residues (TCRAR) thereby ensuring the dissemination of the technical, environmental, and socioeconomic aspects to farmers, live stock producers, extensions service staff, and private sector. Three integrated subsystems for bioconversion of agricultural residues were developed. They were based on (i) energy--manure-recycled water system, (ii) composting and co-composting system, and (iii) food-feed/compost system.

Hydroxylative activity of Aspergillus niger towards androst-4-ene and androst-5-ene steroids.

PubMed

Świzdor, Alina; Panek, Anna; Milecka-Tronina, Natalia

2017-10-01

Aspergillus niger, one of fungal species most frequently used for experimental and industrial-scale biotransformations of various organic compounds, is generally known to transform steroids at 16β position. In this work, application of the strain A. niger KCH910 to bioconversion of dehydroepiandrosterone (DHEA), androstenediol and testosterone is described, with emphasis on the metabolic steps leading to the products. Evidence from this study indicated that incubated 5-ene steroids underwent bioconversion within two metabolic pathways: oxidation by the action of 3β-HSD (3β-hydroxysteroid dehydrogenase) to 4-ene steroids, and minor allylic hydroxylation to epimeric 7-alcohols. Further transformation of the 3-oxo-4-ene metabolites resulted in non-selective 16-hydroxylation. It is the first report on an A. niger strain able to introduce not only 16β- but also 16α-hydroxyl function into steroids. Copyright © 2017. Published by Elsevier Inc.

Green methods of lignocellulose pretreatment for biorefinery development.

PubMed

Capolupo, Laura; Faraco, Vincenza

2016-11-01

Lignocellulosic biomass is the most abundant, low-cost, bio-renewable resource that holds enormous importance as alternative source for production of biofuels and other biochemicals that can be utilized as building blocks for production of new materials. Enzymatic hydrolysis is an essential step involved in the bioconversion of lignocellulose to produce fermentable monosaccharides. However, to allow the enzymatic hydrolysis, a pretreatment step is needed in order to remove the lignin barrier and break down the crystalline structure of cellulose. The present manuscript is dedicated to reviewing the most commonly applied "green" pretreatment processes used in bioconversion of lignocellulosic biomasses within the "biorefinery" concept. In this frame, the effects of different pretreatment methods on lignocellulosic biomass are described along with an in-depth discussion on the benefits and drawbacks of each method, including generation of potentially inhibitory compounds for enzymatic hydrolysis, effect on cellulose digestibility, and generation of compounds toxic for the environment, and energy and economic demand.

Bioconversion Using Lactic Acid Bacteria: Ginsenosides, GABA, and Phenolic Compounds.

PubMed

Lee, Na-Kyoung; Paik, Hyun-Dong

2017-05-28

Lactic acid bacteria (LAB) are used as fermentation starters in vegetable and dairy products and influence the pH and flavors of foods. For many centuries, LAB have been used to manufacture fermented foods; therefore, they are generally regarded as safe. LAB produce various substances, such as lactic acid, β-glucosidase, and β-galactosidase, making them useful as fermentation starters. Existing functional substances have been assessed as fermentation substrates for better component bioavailability or other functions. Representative materials that were bioconverted using LAB have been reported and include minor ginsenosides, γ-aminobutyric acid, equol, aglycones, bioactive isoflavones, genistein, and daidzein, among others. Fermentation mainly involves polyphenol and polysaccharide substrates and is conducted using bacterial strains such as Streptococcus thermophilus, Lactobacillus plantarum, and Bifidobacterium sp. In this review, we summarize recent studies of bioconversion using LAB and discuss future directions for this field.

[Induction and regulation of cellulase expression in filamentous fungi: a review].

PubMed

Zhang, Fei; Bai, Fengwu; Zhao, Xinqing

2016-11-25

Production of bioenergy and bio-based chemicals by using fermentable sugars released from low-cost renewable lignocellulosic biomass has received great attention. Efficient cellulolytic enzymes are crucial for lignocellulose bioconversion, but high cellulase production cost is limiting the bioconversion efficiency of cellulosic biomass and industrial applications of lignocellulose biorefinery. Studies on induction and regulation of cellulase in filamentous fungi will help to further develop superior fungal strains for efficient cellulase production and reduce cellulase production cost. With the advances in high-throughput sequencing and gene manipulation technology using fungal strains, an in-depth understanding of cellulase induction and regulation mechanisms of enzyme expression has been achieved. We reviewed recent progresses in the induction and regulation of cellulase expression in several model filamentous fungi, emphasizing sugar transporters, transcription factors and chromatin remodeling. Future prospects in application of artificial zinc finger proteins for cellulase induction and regulation in filamentous fungi were discussed.

Metabolic Engineering toward Sustainable Production of Nylon-6.

PubMed

Turk, Stefan C H J; Kloosterman, Wigard P; Ninaber, Dennis K; Kolen, Karin P A M; Knutova, Julia; Suir, Erwin; Schürmann, Martin; Raemakers-Franken, Petronella C; Müller, Monika; de Wildeman, Stefaan M A; Raamsdonk, Leonie M; van der Pol, Ruud; Wu, Liang; Temudo, Margarida F; van der Hoeven, Rob A M; Akeroyd, Michiel; van der Stoel, Roland E; Noorman, Henk J; Bovenberg, Roel A L; Trefzer, Axel C

2016-01-15

Nylon-6 is a bulk polymer used for many applications. It consists of the non-natural building block 6-aminocaproic acid, the linear form of caprolactam. Via a retro-synthetic approach, two synthetic pathways were identified for the fermentative production of 6-aminocaproic acid. Both pathways require yet unreported novel biocatalytic steps. We demonstrated proof of these bioconversions by in vitro enzyme assays with a set of selected candidate proteins expressed in Escherichia coli. One of the biosynthetic pathways starts with 2-oxoglutarate and contains bioconversions of the ketoacid elongation pathway known from methanogenic archaea. This pathway was selected for implementation in E. coli and yielded 6-aminocaproic acid at levels up to 160 mg/L in lab-scale batch fermentations. The total amount of 6-aminocaproic acid and related intermediates generated by this pathway exceeded 2 g/L in lab-scale fed-batch fermentations, indicating its potential for further optimization toward large-scale sustainable production of nylon-6.

Thermochemical pretreatments for enhancing succinic acid production from industrial hemp (Cannabis sativa L.).

PubMed

Gunnarsson, Ingólfur B; Kuglarz, Mariusz; Karakashev, Dimitar; Angelidaki, Irini

2015-04-01

The aim of this study was to develop an efficient thermochemical method for treatment of industrial hemp biomass, in order to increase its bioconversion to succinic acid. Industrial hemp was subjected to various thermochemical pretreatments using 0-3% H2SO4, NaOH or H2O2 at 121-180°C prior to enzymatic hydrolysis. The influence of the different pretreatments on hydrolysis and succinic acid production by Actinobacillus succinogenes 130Z was investigated in batch mode, using anaerobic bottles and bioreactors. Enzymatic hydrolysis and fermentation of hemp material pretreated with 3% H2O2 resulted in the highest overall sugar yield (73.5%), maximum succinic acid titer (21.9 g L(-1)), as well as the highest succinic acid yield (83%). Results obtained clearly demonstrated the impact of different pretreatments on the bioconversion efficiency of industrial hemp into succinic acid. Copyright © 2015. Published by Elsevier Ltd.

Encapsulates for Food Bioconversions and Metabolite Production

NASA Astrophysics Data System (ADS)

Breguet, Véronique; Vojinovic, Vojislav; Marison, Ian W.

The control of production costs in the food industry must be very strict as a result of the relatively low added value of food products. Since a wide variety of enzymes and/or cells are employed in the food industry for starch processing, cheese making, food preservation, lipid hydrolysis and other applications, immobilization of the cells and/or enzymes has been recognized as an attractive approach to improving food processes while minimizing costs. This is due to the fact that biocatalyst immobilization allows for easier separation/purification of the product and reutilization of the biocatalyst. The advantages of the use of immobilized systems are many, and they have a special relevance in the area of food technology, especially because industrial processes using immobilized biosystems are usually characterized by lower capital/energy costs and better logistics. The main applications of immobilization, related to the major processes of food bioconversions and metabolite production, will be described and discussed in this chapter.

Bioconversion of waste biomass to useful products

DOEpatents

Grady, J.L.; Chen, G.J.

1998-10-13

A process is provided for converting waste biomass to useful products by gasifying the biomass to produce synthesis gas and converting the synthesis gas substrate to one or more useful products. The present invention is directed to the conversion of biomass wastes including municipal solid waste, sewage sludge, plastic, tires, agricultural residues and the like, as well as coal, to useful products such as hydrogen, ethanol and acetic acid. The overall process includes the steps of gasifying the waste biomass to produce raw synthesis gas, cooling the synthesis gas, converting the synthesis gas to the desired product or products using anaerobic bioconversion, and then recovering the product or products. In accordance with a particular embodiment of the present invention, waste biomass is converted to synthesis gas containing carbon monoxide and, then, the carbon monoxide is converted to hydrogen by an anaerobic microorganism ERIH2, Bacillus smithii ATCC No. 55404. 82 figs.

Bioconversion of waste biomass to useful products

DOEpatents

Grady, James L.; Chen, Guang Jiong

1998-01-01

A process is provided for converting waste biomass to useful products by gasifying the biomass to produce synthesis gas and converting the synthesis gas substrate to one or more useful products. The present invention is directed to the conversion of biomass wastes including municipal solid waste, sewage sludge, plastic, tires, agricultural residues and the like, as well as coal, to useful products such as hydrogen, ethanol and acetic acid. The overall process includes the steps of gasifying the waste biomass to produce raw synthesis gas, cooling the synthesis gas, converting the synthesis gas to the desired product or products using anaerobic bioconversion, and then recovering the product or products. In accordance with a particular embodiment of the present invention, waste biomass is converted to synthesis gas containing carbon monoxide and, then, the carbon monoxide is converted to hydrogen by an anaerobic microorganism ERIH2, bacillus smithii ATCC No. 55404.

Influence of ultrasonication on anaerobic bioconversion of sludge.

PubMed

Mao, Taohong; Show, Kuan-Yeow

2007-04-01

The influence of ultrasonication on hydrolysis, acidogenesis, and methanogenesis in anaerobic decomposition of sludge was investigated. The sonicated sludge exhibited prehydrolysis and preacidogenesis effects in the anaerobic decomposition process. First-order hydrolysis rates increased from 0.0384 day(-1) in the control digester to 0.0672 day(-1) in the digester fed, with sludge sonicated at 0.52 W/mL. The sonication appeared to be ineffective in relation to acidogenesis reaction rates, but it provided a better buffering capacity to diminish the adverse effect of acidification. Digesters fed with sonicated sludge demonstrated enhanced methanogenesis over the control unit. Determination by coenzyme F420 verified that sonication is able to promote the growth of methanogenic biomass and facilitate a positive methanogenic microbial development in suppressing the initial methanogenesis limitation. The results suggest that ultrasonication could enhance anaerobic decomposition of sludge, resulting in an accelerated bioconversion, improved organics degradation, improved biogas production, and increased methane content.

Application of Taguchi Design and Response Surface Methodology for Improving Conversion of Isoeugenol into Vanillin by Resting Cells of Psychrobacter sp. CSW4.

PubMed

Ashengroph, Morahem; Nahvi, Iraj; Amini, Jahanshir

2013-01-01

For all industrial processes, modelling, optimisation and control are the keys to enhance productivity and ensure product quality. In the current study, the optimization of process parameters for improving the conversion of isoeugenol to vanillin by Psychrobacter sp. CSW4 was investigated by means of Taguchi approach and Box-Behnken statistical design under resting cell conditions. Taguchi design was employed for screening the significant variables in the bioconversion medium. Sequentially, Box-Behnken design experiments under Response Surface Methodology (RSM) was used for further optimization. Four factors (isoeugenol, NaCl, biomass and tween 80 initial concentrations), which have significant effects on vanillin yield, were selected from ten variables by Taguchi experimental design. With the regression coefficient analysis in the Box-Behnken design, a relationship between vanillin production and four significant variables was obtained, and the optimum levels of the four variables were as follows: initial isoeugenol concentration 6.5 g/L, initial tween 80 concentration 0.89 g/L, initial NaCl concentration 113.2 g/L and initial biomass concentration 6.27 g/L. Under these optimized conditions, the maximum predicted concentration of vanillin was 2.25 g/L. These optimized values of the factors were validated in a triplicate shaking flask study and an average of 2.19 g/L for vanillin, which corresponded to a molar yield 36.3%, after a 24 h bioconversion was obtained. The present work is the first one reporting the application of Taguchi design and Response surface methodology for optimizing bioconversion of isoeugenol into vanillin under resting cell conditions.

Design and characterization of a prototype enzyme microreactor: quantification of immobilized transketolase kinetics.

PubMed

Matosevic, S; Lye, G J; Baganz, F

2010-01-01

In this work, we describe the design of an immobilized enzyme microreactor (IEMR) for use in transketolase (TK) bioconversion process characterization. The prototype microreactor is based on a 200-microm ID fused silica capillary for quantitative kinetic analysis. The concept is based on the reversible immobilization of His(6)-tagged enzymes via Ni-NTA linkage to surface derivatized silica. For the initial microreactor design, the mode of operation is a stop-flow analysis which promotes higher degrees of conversion. Kinetics for the immobilized TK-catalysed synthesis of L-erythrulose from substrates glycolaldehyde (GA) and hydroxypyruvate (HPA) were evaluated based on a Michaelis-Menten model. Results show that the TK kinetic parameters in the IEMR (V(max(app)) = 0.1 +/- 0.02 mmol min(-1), K(m(app)) = 26 +/- 4 mM) are comparable with those measured in free solution. Furthermore, the k(cat) for the microreactor of 4.1 x 10(5) s(-1) was close to the value for the bioconversion in free solution. This is attributed to the controlled orientation and monolayer surface coverage of the His(6)-immobilized TK. Furthermore, we show quantitative elution of the immobilized TK and the regeneration and reuse of the derivatized capillary over five cycles. The ability to quantify kinetic parameters of engineered enzymes at this scale has benefits for the rapid and parallel evaluation of evolved enzyme libraries for synthetic biology applications and for the generation of kinetic models to aid bioconversion process design and bioreactor selection as a more efficient alternative to previously established microwell-based systems for TK bioprocess characterization.

Bioconversion of Gibberellin Fermentation Residue into Feed Supplement and Organic Fertilizer Employing Housefly (Musca domestica L.) Assisted by Corynebacterium variabile.

PubMed

Yang, Sen; Xie, Jiufeng; Hu, Nan; Liu, Yixiong; Zhang, Jiner; Ye, Xiaobin; Liu, Ziduo

2015-01-01

The accumulation of a considerable quantity of gibberellin fermentation residue (GFR) during gibberellic acid A3 (GA3) production not only results in the waste of many resources, but also poses a potential hazard to the environment, indicating that the safe treatment of GFR has become an urgent issue for GA3 industry. The key to recycle GFR is converting it into an available resource and removing the GA3 residue. To this end, we established a co-bioconversion process in this study using house fly larvae (HFL) and microbes (Corynebacterium variabile) to convert GFR into insect biomass and organic fertilizer. About 85.5% GA3 in the GFR was removed under the following optimized solid-state fermentation conditions: 60% GFR, 40% rice straw powder, pH 8.5 and 6 days at 26 °C. A total of 371 g housefly larvae meal and 2,064 g digested residue were bio-converted from 3,500 g raw GFR mixture contaning1, 400 g rice straw in the unit of (calculated) dry matter. HFL meal derived from GFR contained 56.4% protein, 21.6% fat, and several essential amino acids, suggesting that it is a potential alternative animal feed protein source. Additionally, the digested GFR could be utilized as an organic fertilizer with a content of 3.2% total nitrogen, 2.0% inorganic phosphorus, 1.3% potassium and 91.5% organic matter. This novel GFR bio-conversion method can mitigate potential environmental pollution and recycle the waste resources.

Production of dihydrodaidzein and dihydrogenistein by a novel oxygen-tolerant bovine rumen bacterium in the presence of atmospheric oxygen.

PubMed

Zhao, Hui; Wang, Xiu-Ling; Zhang, Hong-Lei; Li, Chao-Dong; Wang, Shi-Ying

2011-11-01

The original bovine rumen bacterial strain Niu-O16, capable of anaerobically bioconverting isoflavones daidzein and genistein to dihydrodaidzein (DHD) and dihydrogenistein (DHG), respectively, is a rod-shaped obligate anaerobic bacterium. After a long-term domestication, an oxygen-tolerant bacterium, which we named Aeroto-Niu-O16 was obtained. Strain Aeroto-Niu-O16, which can grow in the presence of atmospheric oxygen, differed from the original obligate anaerobic bacterium Niu-O16 by various characteristics, including a change in bacterial shape (from rod to filament), in biochemical traits (from indole negative to indole positive and from amylohydrolysis positive to negative), and point mutations in 16S rRNA gene (G398A and G438A). We found that strain Aeroto-Niu-O16 not only grew aerobically but also converted isoflavones daidzein and genistein to DHD and DHG in the presence of atmospheric oxygen. The bioconversion rate of daidzein and genistein by strain Aeroto-Niu-O16 was 60.3% and 74.1%, respectively. And the maximum bioconversion capacity for daidzein was 1.2 and 1.6 mM for genistein. Furthermore, when we added ascorbic acid (0.15%, m/v) in the cultural medium, the bioconversion rate of daidzein was increased from 60.3% to 71.7%, and that of genistein from 74.1% to 89.2%. This is the first reported oxygen-tolerant isoflavone biotransforming pure culture capable of both growing and executing the reductive activity under aerobic conditions. © Springer-Verlag 2011

Immobilised enzyme microreactor for screening of multi-step bioconversions: characterisation of a de novo transketolase-ω-transaminase pathway to synthesise chiral amino alcohols.

PubMed

Matosevic, S; Lye, G J; Baganz, F

2011-09-20

Complex molecules are synthesised via a number of multi-step reactions in living cells. In this work, we describe the development of a continuous flow immobilized enzyme microreactor platform for use in evaluation of multi-step bioconversion pathways demonstrating a de novo transketolase/ω-transaminase-linked asymmetric amino alcohol synthesis. The prototype dual microreactor is based on the reversible attachment of His₆-tagged enzymes via Ni-NTA linkage to two surface derivatised capillaries connected in series. Kinetic parameters established for the model transketolase (TK)-catalysed conversion of lithium-hydroxypyruvate (Li-HPA) and glycolaldehyde (GA) to L-erythrulose using a continuous flow system with online monitoring of reaction output was in good agreement with kinetic parameters determined for TK in stop-flow mode. By coupling the transketolase catalysed chiral ketone forming reaction with the biocatalytic addition of an amine to the TK product using a transaminase (ω-TAm) it is possible to generate chiral amino alcohols from achiral starting compounds. We demonstrated this in a two-step configuration, where the TK reaction was followed by the ω-TAm-catalysed amination of L-erythrulose to synthesise 2-amino-1,3,4-butanetriol (ABT). Synthesis of the ABT product via the dual reaction and the on-line monitoring of each component provided a full profile of the de novo two-step bioconversion and demonstrated the utility of this microreactor system to provide in vitro multi-step pathway evaluation. Copyright © 2011 Elsevier B.V. All rights reserved.

Bioconversion of Gibberellin Fermentation Residue into Feed Supplement and Organic Fertilizer Employing Housefly (Musca domestica L.) Assisted by Corynebacterium variabile

PubMed Central

Yang, Sen; Xie, Jiufeng; Hu, Nan; Liu, Yixiong; Zhang, Jiner; Ye, Xiaobin; Liu, Ziduo

2015-01-01

The accumulation of a considerable quantity of gibberellin fermentation residue (GFR) during gibberellic acid A3 (GA3) production not only results in the waste of many resources, but also poses a potential hazard to the environment, indicating that the safe treatment of GFR has become an urgent issue for GA3 industry. The key to recycle GFR is converting it into an available resource and removing the GA3 residue. To this end, we established a co-bioconversion process in this study using house fly larvae (HFL) and microbes (Corynebacterium variabile) to convert GFR into insect biomass and organic fertilizer. About 85.5% GA3 in the GFR was removed under the following optimized solid-state fermentation conditions: 60% GFR, 40% rice straw powder, pH 8.5 and 6 days at 26°C. A total of 371g housefly larvae meal and 2,064g digested residue were bio-converted from 3,500g raw GFR mixture contaning1, 400g rice straw in the unit of (calculated) dry matter. HFL meal derived from GFR contained 56.4% protein, 21.6% fat, and several essential amino acids, suggesting that it is a potential alternative animal feed protein source. Additionally, the digested GFR could be utilized as an organic fertilizer with a content of 3.2% total nitrogen, 2.0% inorganic phosphorus, 1.3% potassium and 91.5% organic matter. This novel GFR bio-conversion method can mitigate potential environmental pollution and recycle the waste resources. PMID:25992605

Production of raw starch-degrading enzyme by Aspergillus sp. and its use in conversion of inedible wild cassava flour to bioethanol.

PubMed

Moshi, Anselm P; Hosea, Ken M M; Elisante, Emrode; Mamo, Gashaw; Önnby, Linda; Nges, Ivo Achu

2016-04-01

The major bottlenecks in achieving competitive bioethanol fuel are the high cost of feedstock, energy and enzymes employed in pretreatment prior to fermentation. Lignocellulosic biomass has been proposed as an alternative feedstock, but because of its complexity, economic viability is yet to be realized. Therefore, research around non-conventional feedstocks and deployment of bioconversion approaches that downsize the cost of energy and enzymes is justified. In this study, a non-conventional feedstock, inedible wild cassava was used for bioethanol production. Bioconversion of raw starch from the wild cassava to bioethanol at low temperature was investigated using both a co-culture of Aspergillus sp. and Saccharomyces cerevisiae, and a monoculture of the later with enzyme preparation from the former. A newly isolated strain of Aspergillus sp. MZA-3 produced raw starch-degrading enzyme which displayed highest activity of 3.3 U/mL towards raw starch from wild cassava at 50°C, pH 5.5. A co-culture of MZA-3 and S. cerevisiae; and a monoculture of S. cerevisiae and MZA-3 enzyme (both supplemented with glucoamylase) resulted into bioethanol yield (percentage of the theoretical yield) of 91 and 95 at efficiency (percentage) of 84 and 96, respectively. Direct bioconversion of raw starch to bioethanol was achieved at 30°C through the co-culture approach. This could be attractive since it may significantly downsize energy expenses. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Valorization of industrial waste and by-product streams via fermentation for the production of chemicals and biopolymers.

PubMed

Koutinas, Apostolis A; Vlysidis, Anestis; Pleissner, Daniel; Kopsahelis, Nikolaos; Lopez Garcia, Isabel; Kookos, Ioannis K; Papanikolaou, Seraphim; Kwan, Tsz Him; Lin, Carol Sze Ki

2014-04-21

The transition from a fossil fuel-based economy to a bio-based economy necessitates the exploitation of synergies, scientific innovations and breakthroughs, and step changes in the infrastructure of chemical industry. Sustainable production of chemicals and biopolymers should be dependent entirely on renewable carbon. White biotechnology could provide the necessary tools for the evolution of microbial bioconversion into a key unit operation in future biorefineries. Waste and by-product streams from existing industrial sectors (e.g., food industry, pulp and paper industry, biodiesel and bioethanol production) could be used as renewable resources for both biorefinery development and production of nutrient-complete fermentation feedstocks. This review focuses on the potential of utilizing waste and by-product streams from current industrial activities for the production of chemicals and biopolymers via microbial bioconversion. The first part of this review presents the current status and prospects on fermentative production of important platform chemicals (i.e., selected C2-C6 metabolic products and single cell oil) and biopolymers (i.e., polyhydroxyalkanoates and bacterial cellulose). In the second part, the qualitative and quantitative characteristics of waste and by-product streams from existing industrial sectors are presented. In the third part, the techno-economic aspects of bioconversion processes are critically reviewed. Four case studies showing the potential of case-specific waste and by-product streams for the production of succinic acid and polyhydroxyalkanoates are presented. It is evident that fermentative production of chemicals and biopolymers via refining of waste and by-product streams is a highly important research area with significant prospects for industrial applications.

Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods

Treesearch

G. S. Wang; X. J. Pan; Junyong Zhu; Roland Gleisner; D. Rockwood

2009-01-01

This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180[...

Saccharification of rice straw by cellulase from a local Trichoderma harzianum SNRS3 for biobutanol production.

PubMed

Rahnama, Nooshin; Foo, Hooi Ling; Abdul Rahman, Nor Aini; Ariff, Arbakariya; Md Shah, Umi Kalsom

2014-12-12

Rice straw has shown to be a promising agricultural by-product in the bioconversion of biomass to value-added products. Hydrolysis of cellulose, a main constituent of lignocellulosic biomass, is a requirement for fermentable sugar production and its subsequent bioconversion to biofuels such as biobutanol. The high cost of commercial enzymes is a major impediment to the industrial application of cellulases. Therefore, the use of local microbial enzymes has been suggested. Trichoderma harzianum strains are potential CMCase and β-glucosidase producers. However, few researches have been reported on cellulase production by T. harzianum and the subsequent use of the crude cellulase for cellulose enzymatic hydrolysis. For cellulose hydrolysis to be efficiently performed, the presence of the whole set of cellulase components including exoglucanase, endoglucanase, and β-glucosidase at a considerable concentration is required. Biomass recalcitrance is also a bottleneck in the bioconversion of agricultural residues to value-added products. An effective pretreatment could be of central significance in the bioconversion of biomass to biofuels. Rice straw pretreated using various concentrations of NaOH was subjected to enzymatic hydrolysis. The saccharification of rice straw pretreated with 2% (w/v) NaOH using crude cellulase from local T. harzianum SNRS3 resulted in the production of 29.87 g/L reducing sugar and a yield of 0.6 g/g substrate. The use of rice straw hydrolysate as carbon source for biobutanol fermentation by Clostridium acetobutylicum ATCC 824 resulted in an ABE yield, ABE productivity, and biobutanol yield of 0.27 g/g glucose, 0.04 g/L/h and 0.16 g/g glucose, respectively. As a potential β-glucosidase producer, T. harzianum SNRS3 used in this study was able to produce β-glucosidase at the activity of 173.71 U/g substrate. However, for cellulose hydrolysis to be efficient, Filter Paper Activity at a considerable concentration is also required to initiate the hydrolytic reaction. According to the results of our study, FPase is a major component of cellulose hydrolytic enzyme complex system and the reducing sugar rate-limiting enzyme. Our study revealed that rice straw hydrolysate served as a potential substrate for biobutanol production and FPase is a rate-limiting enzyme in saccharification.

Nanostructure enzyme assemblies for biomass conversion

USDA-ARS?s Scientific Manuscript database

Biomass represents a vast resource for production of the world’s fuel and chemical feedstock needs. The use of enzymes to effect these bioconversions offers an alternative that is potentially more specific and environmentally-friendly than harsher chemical methodologies. Some species of anaerobic ...

Bioconversion of oxygen-pretreated Kraft lignin to microbial lipid with oleaginous Rhodococcus opacus DSM 1069

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wei, Zhen; Zeng, Guangming; Huang, Fang

2015-04-09

Kraft lignin (KL) from black liquor is an abundantly available, inexpensive aromatic resource that is regarded as a low value compound by the pulp and paper industry, necessitating the development of new applications.

Science and Technology in a Conserving Society.

ERIC Educational Resources Information Center

Press, Frank

1979-01-01

The science and technology advisor to the President of the United States presents the challenges facing Americans today in the fields of science and technology. The major topics focused on are people and development, agriculture, biomass and bioconversion, and regulation. (SA)

BIOCONVERSION AND MASS TRANSFER OF PESTICIDES IN A MODEL WETLANDS SYSTEM

EPA Science Inventory

The widespread use of agrichemicals over the years has impaired the nation's water quality through contamination of soil and of surface and groundwaters. A constructed wetlands environment has natural restorative processes which are attractive methods for improving water qu...

Bioconversion of giant reed (Arundo donax L.) hemicellulose hydrolysate to ethanol by Scheffersomyces stipitis CBS6054

Treesearch

Danilo Scordia; Salvatore L. Cosentino; Jae-Won Lee; Thomas W. Jeffries

2012-01-01

The objective of this study was to evaluate the production of ethanol by Scheffersomyces (Pichia) stipitis CBS6054, a native xylose fermenting yeast, from sugars contained in the giant reed (Arundo donax L.) hemicellulosic hydrolysate.

Bioconversion of Agave tequilana fructans by exo-inulinases from indigenous Aspergillus niger CH-A-2010 enhances ethanol production from raw Agave tequilana juice.

PubMed

Huitrón, Carlos; Pérez, Rosalba; Gutiérrez, Luís; Lappe, Patricia; Petrosyan, Pavel; Villegas, Jesús; Aguilar, Cecilia; Rocha-Zavaleta, Leticia; Blancas, Abel

2013-01-01

Agave tequilana fructans are the source of fermentable sugars for the production of tequila. Fructans are processed by acid hydrolysis or by cooking in ovens at high temperature. Enzymatic hydrolysis is considered an alternative for the bioconversion of fructans. We previously described the isolation of Aspergillus niger CH-A-2010, an indigenous strain that produces extracellular inulinases. Here we evaluated the potential application of A. niger CH-A-2010 inulinases for the bioconversion of A. tequilana fructans, and its impact on the production of ethanol. Inulinases were analyzed by Western blotting and thin layer chromatography. Optimal pH and temperature conditions for inulinase activity were determined. The efficiency of A. niger CH-A-2010 inulinases was compared with commercial enzymes and with acid hydrolysis. The hydrolysates obtained were subsequently fermented by Saccharomyces cerevisiae to determine the efficiency of ethanol production. Results indicate that A. niger CH-A-2010 predominantly produces an exo-inulinase activity. Optimal inulinase activity occurred at pH 5.0 and 50 °C. Hydrolysis of raw agave juice by CH-A-2010 inulinases yielded 33.5 g/l reducing sugars, compared with 27.3 g/l by Fructozyme(®) (Novozymes Corp, Bagsværd, Denmark) and 29.4 g/l by acid hydrolysis. After fermentation of hydrolysates, we observed that the conversion efficiency of sugars into ethanol was 97.5 % of the theoretical ethanol yield for enzymatically degraded agave juice, compared to 83.8 % for acid-hydrolyzed juice. These observations indicate that fructans from raw Agave tequilana juice can be efficiently hydrolyzed by using A. niger CH-A-2010 inulinases, and that this procedure impacts positively on the production of ethanol.

A n-3 PUFA depletion applied to rainbow trout fry (Oncorhynchus mykiss) does not modulate its subsequent lipid bioconversion capacity.

PubMed

Mellery, Julie; Brel, Jonathan; Dort, Junio; Geay, Florian; Kestemont, Patrick; Francis, David S; Larondelle, Yvan; Rollin, Xavier

2017-01-01

Nutritional strategies are currently developed to produce farmed fish rich in n-3 long-chain PUFA (LC-PUFA) whilst replacing fish oil by plant-derived oils in aquafeeds. The optimisation of such strategies requires a thorough understanding of fish lipid metabolism and its nutritional modulation. The present study evaluated the fatty acid bioconversion capacity of rainbow trout (Oncorhynchus mykiss) fry previously depleted in n-3 PUFA through a 60-d pre-experimental feeding period with a sunflower oil-based diet (SO) followed by a 36-d experimental period during which fish were fed either a linseed oil-based diet (LO) (this treatment being called SO/LO) or a fish oil-based diet (FO) (this treatment being called SO/FO). These treatments were compared with fish continuously fed on SO, LO or FO for 96 d. At the end of the 36-d experimental period, SO/LO and SO/FO fish recovered >80 % of the n-3 LC-PUFA reported for LO and FO fish, respectively. Fish fed on LO showed high apparent in vivo elongation and desaturation activities along the n-3 biosynthesis pathway. However, at the end of the experimental period, no impact of the fish n-3 PUFA depletion was observed on apparent in vivo elongation and desaturation activities of SO/LO fish as compared with LO fish. In contrast, the fish n-3 PUFA depletion negatively modulated the n-6 PUFA bioconversion capacity of fish in terms of reduced apparent in vivo elongation and desaturation activities. The effects were similar after 10 or 36 d of the experimental period, indicating the absence of short-term effects.

Effect of initial moisture content and chip size on the bioconversion efficiency of softwood lignocellulosics.

PubMed

Cullis, Ian F; Saddler, John N; Mansfield, Shawn D

2004-02-20

Previous optimization strategies for the bioconversion of lignocellulosics by steam explosion technologies have focused on the effects of temperature, pH, and treatment time, but have not accounted for changes in severity brought about by properties inherent in the starting feedstock. Consequently, this study evaluated the effects of chip properties, feedstock size (40-mesh, 1.5 x 1.5 cm, 5 x 5 cm), and moisture content (12% and 30%) on the overall bioconversion process, and more specifically on the efficacy of removal of recalcitrant lignin from the lignocellulosic substrates following steam explosion. Increasing chip size resulted in an improvement in the solids recovery, with concurrent increases in the water soluble, hemicellulose-derived sugar recovery (7.5%). This increased recovery is a result of a decrease in the "relative severity" of the pretreatment as chip size increases. Additionally, the decreased relative severity minimized the condensation of the recalcitrant residual lignin and therefore increased the efficacy of peroxide fractionation, where a 60% improvement in lignin removal was possible with chips of larger initial size. Similarly, increased initial moisture content reduced the relative severity of the pretreatment, generating improved solids and hemicellulose-derived carbohydrate recovery. Both increased chip size and higher initial moisture content results in a substrate that performs better during peroxide delignification, and consequently enzymatic hydrolysis. Furthermore, a post steam-explosion refining step increased hemicellulose-derived sugar recovery and was most effectively delignified (to as low as 6.5%). The refined substrate could be enzymatically hydrolyzed to very high levels (98%) and relatively fast rates (1.23 g/L/h). Copyright 2004 Wiley Periodicals, Inc.

Biosolids accumulation and biodegradation of domestic wastewater treatment plant sludge by developed liquid state bioconversion process using a batch fermenter.

PubMed

Alam, Md Zahangir; Fakhru'l-Razi, A; Molla, Abul H

2003-09-01

The biosolids accumulation and biodegradation of domestic wastewater treatment plant (DWTP) sludge by filamentous fungi have been investigated in a batch fermenter. The filamentous fungi Aspergillus niger and Penicillium corylophilum isolated from wastewater and DWTP sludge was used to evaluate the treatment performance. The optimized mixed inoculum (A. niger and P. corylophilum) and developed process conditions (co-substrate and its concentration, temperature, initial pH, inoculum size, and aeration and agitation rate) were incorporated to accelerate the DWTP sludge treatment process. The results showed that microbial treatment of higher strength of DWTP sludge (4% w/w of TSS) was highly influenced by the liquid state bioconversion (LSB) process. In developed bioconversion processes, 93.8 g/kg of biosolids was enriched with fungal biomass protein of 30 g/kg. Enrichment of nutrients such as nitrogen (N), phosphorous (P), potassium (K) in biosolids was recorded in 6.2% (w/w), 3.1% (w/w) and 0.15% (w/w) from its initial values of 4.8% (w/w), 2.0% (w/w) and 0.08% (w/w) respectively after 10 days of fungal treatment. The biodegradation results revealed that 98.8% of TSS, 98.2% of TDS, 97.3% of turbidity, 80.2% of soluble protein, 98.8% of reducing sugar and 92.7% of COD in treated DWTP sludge supernatant were removed after 8 days of microbial treatment. The specific resistance to filtration (SRF) in treated sludge (1.4x10(12) m/kg) was decreased tremendously by the microbial treatment of DWTP sludge after 6 days of fermentation compared to untreated sample (85x10(12) m/kg).

Modification of Alternan by Dextranase

USDA-ARS?s Scientific Manuscript database

Alternan is a unique glucan with a backbone structure of alternating alpha-(1=-6) and alpha-(1=-3) linkages. Previously, we isolated strains of Penicillium sp. that modify native, high molecular weight alternan in a novel bioconversion process to a lower molecular weight form with solution viscosit...

Science Packets.

ERIC Educational Resources Information Center

Maine Audubon Society, Falmouth.

This publication is an energy guide for teachers. It contains discussions and illustrations of five major topics: the sun's radiant energy, solar collection, solar cells, bioconversion (wood, grains, waste), and wind. Each section includes a listing of the concepts contained within and a brief discussion-explanation section. There is a short…

Digital image processing based identification of nodes and internodes of chopped biomass stems

USDA-ARS?s Scientific Manuscript database

Chemical composition of biomass feedstock is an important parameter for optimizing the yield and economics of various bioconversion pathways. Although understandably, the chemical composition of biomass varies among species, varieties, and plant components, there is distinct variation even among ste...

Using isolated cell wall xylan to identify recalcitrant oligosaccharides

USDA-ARS?s Scientific Manuscript database

Herbaceous biomass is a renewable source of carbohydrates with potential for use in microbial conversion to biofuels. Xylan comprises 20-40% of herbaceous biomass cell wall material and its full depolymerization benefits the economics of bioconversion. To understand the limitations of commercial enz...

Bioconversion of marine carotenoids and their health functions

USDA-ARS?s Scientific Manuscript database

Fucoxanthin (FX), found in edible brown seaweeds, exhibits anti-obesity and anti-diabetic effects. In the body, FX is converted to fucoxanthinol (FXOH) and amarouciaxanthin A and accumulates in adipose tissue and other tissues. It was suggested that FXOH and amarouciaxanthin A were active metaboli...

Physiological activities of hydroxyl fatty acids

USDA-ARS?s Scientific Manuscript database

In the search of value-added products from surplus soybean oil, we produced many new hydroxy fatty acids through microbial bioconversion. Hydroxy fatty acids are used in a wide range of industrial products, such as resins, waxes, nylons plastics, lubricants, cosmetics, and additives in coatings and...

Combined submerged and solid substrate fermentation for the bioconversion of lignocellulose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viesturs, U.E.; Strikauska, S.V.; Leite, M.P.

1987-01-01

A novel two-stage bioreactor has been designed for a combined submerged (SF) and solid substrate fermentation (SSF) of wheat straw. The straw was pretreated with steam, and cellulases from the culture fluid of Trichoderma reesei were adsorbed on it for increased bio-convertibility. SSF was conducted in the top part of the bioreactor by inoculating the straw with a 36-h mycelial culture of T. reesei, or Coriolus versicolor. In the bottom part of the fermenter, Endomycopsis fibuliger was grown in SF. The SF liquor was recirculated through the SSF stage at 24 hour intervals to remove glucose and other metabolites thatmore » may inhibit growth, and to maintain optimum moisture level and temperature. The removed glucose and other metabolites provided nutrients for the yeast in the SF stage. The combined fermentation resulted in overall higher biomass yield, increased bioconversion, increased cellulase production, and increased digestibility compared with single SSF or SF. (Refs. 16).« less

Bioconversion of distillers’ grains hydrolysates to advanced biofuels by an Escherichia coli co-culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Fang; Wu, Weihua; Tran-Gyamfi, Mary B.

Here, the first generation bioethanol production utilizes the starch fraction of maize, which accounts for approximately 60% of the ash-free dry weight of the grain. Scale-up of this technology for fuels applications has resulted in a massive supply of distillers’ grains with solubles (DGS) coproduct, which is rich in cellulosic polysaccharides and protein. It was surmised that DGS would be rapidly adopted for animal feed applications, however, this has not been observed based on inconsistency of the product stream and other logistics-related risks, especially toxigenic contaminants. Therefore, efficient valorization of DGS for production of petroleum displacing products will significantly improvemore » the techno-economic feasibility and net energy return of the established starch bioethanol process. In this study, we demonstrate ‘one-pot’ bioconversion of the protein and carbohydrate fractions of a DGS hydrolysate into C4 and C5 fusel alcohols through development of a microbial consortium incorporating two engineered Escherichia coli biocatalyst strains.« less

Development of rapid bioconversion with integrated recycle technology for ethanol production from extractive ammonia pretreated corn stover.

PubMed

Jin, Mingjie; Liu, Yanping; da Costa Sousa, Leonardo; Dale, Bruce E; Balan, Venkatesh

2017-08-01

High enzyme loading and low productivity are two major issues impeding low cost ethanol production from lignocellulosic biomass. This work applied rapid bioconversion with integrated recycle technology (RaBIT) and extractive ammonia (EA) pretreatment for conversion of corn stover (CS) to ethanol at high solids loading. Enzymes were recycled via recycling unhydrolyzed solids. Enzymatic hydrolysis with recycled enzymes and fermentation with recycled yeast cells were studied. Both enzymatic hydrolysis time and fermentation time were shortened to 24 h. Ethanol productivity was enhanced by two times and enzyme loading was reduced by 30%. Glucan and xylan conversions reached as high as 98% with an enzyme loading of as low as 8.4 mg protein per g glucan. The overall ethanol yield was 227 g ethanol/kg EA-CS (191 g ethanol/kg untreated CS). Biotechnol. Bioeng. 2017;114: 1713-1720. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Fed-batch hydrolysate addition and cell separation by settling in high cell density lignocellulosic ethanol fermentations on AFEX™ corn stover in the Rapid Bioconversion with Integrated recycling Technology process.

PubMed

Sarks, Cory; Jin, Mingjie; Balan, Venkatesh; Dale, Bruce E

2017-09-01

The Rapid Bioconversion with Integrated recycling Technology (RaBIT) process uses enzyme and yeast recycling to improve cellulosic ethanol production economics. The previous versions of the RaBIT process exhibited decreased xylose consumption using cell recycle for a variety of different micro-organisms. Process changes were tested in an attempt to eliminate the xylose consumption decrease. Three different RaBIT process changes were evaluated in this work including (1) shortening the fermentation time, (2) fed-batch hydrolysate addition, and (3) selective cell recycling using a settling method. Shorting the RaBIT fermentation process to 11 h and introducing fed-batch hydrolysate addition eliminated any xylose consumption decrease over ten fermentation cycles; otherwise, decreased xylose consumption was apparent by the third cell recycle event. However, partial removal of yeast cells during recycle was not economical when compared to recycling all yeast cells.

Bioconversion of distillers’ grains hydrolysates to advanced biofuels by an Escherichia coli co-culture

DOE PAGES

Liu, Fang; Wu, Weihua; Tran-Gyamfi, Mary B.; ...

2017-11-09

Here, the first generation bioethanol production utilizes the starch fraction of maize, which accounts for approximately 60% of the ash-free dry weight of the grain. Scale-up of this technology for fuels applications has resulted in a massive supply of distillers’ grains with solubles (DGS) coproduct, which is rich in cellulosic polysaccharides and protein. It was surmised that DGS would be rapidly adopted for animal feed applications, however, this has not been observed based on inconsistency of the product stream and other logistics-related risks, especially toxigenic contaminants. Therefore, efficient valorization of DGS for production of petroleum displacing products will significantly improvemore » the techno-economic feasibility and net energy return of the established starch bioethanol process. In this study, we demonstrate ‘one-pot’ bioconversion of the protein and carbohydrate fractions of a DGS hydrolysate into C4 and C5 fusel alcohols through development of a microbial consortium incorporating two engineered Escherichia coli biocatalyst strains.« less

Integrated bioconversion of syngas into bioethanol and biopolymers.

PubMed

Lagoa-Costa, Borja; Abubackar, Haris Nalakath; Fernández-Romasanta, María; Kennes, Christian; Veiga, María C

2017-09-01

Syngas bioconversion is a promising method for bioethanol production, but some VFA remains at the end of fermentation. A two-stage process was set-up, including syngas fermentation as first stage under strict anaerobic conditions using C. autoethanogenum as inoculum, with syngas (CO/CO 2 /H 2 /N 2 , 30/10/20/40) as gaseous substrate. The second stage consisted in various fed-batch assays using a highly enriched PHA accumulating biomass as inoculum, where the potential for biopolymer production from the remaining acetic acid at the end of the syngas fermentation was evaluated. All of the acetic acid was consumed and accumulated as biopolymer, while ethanol and 2,3-butanediol remained basically unused. It can be concluded that a high C/N ratio in the effluent from the syngas fermentation stage was responsible for non-consumption of alcohols. A maximum PHA content of 24% was reached at the end of the assay. Copyright © 2017 Elsevier Ltd. All rights reserved.

Glucose bioconversion profile in the syngas-metabolizing species Clostridium carboxidivorans.

PubMed

Fernández-Naveira, Ánxela; Veiga, María C; Kennes, Christian

2017-11-01

Some clostridia produce alcohols (ethanol, butanol, hexanol) from gases (CO, CO 2 , H 2 ) and others from carbohydrates (e.g., glucose). C. carboxidivorans can metabolize both gases as well as glucose. However, its bioconversion profile on glucose had not been reported. It was observed that C. carboxidivorans does not follow a typical solventogenic stage when grown on glucose. Indeed, at pH 6.2, it produced first a broad range of acids (acetic, butyric, hexanoic, formic, and lactic acids), several of which are generally not found, under similar conditions, during gas fermentation. Medium acidification did not allow the conversion of fatty acids into solvents. Production of some alcohols from glucose was observed in C. carboxidivorans but at high pH rather than under acidic conditions, and the total concentration of those solvents was low. At high pH, formic acid was produced first and later converted to acetic acid, but organic acids were not metabolized at low pH. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioconversion of rice straw into a soil-like substrate

NASA Astrophysics Data System (ADS)

Yu, Chengying; Liu, Hong; Xing, Yidong; Manukovsky, N. S.; Kovalev, V. S.; Gurevich, Yu. L.

To increase the closure of bioregenerative life support systems (BLSS), the bioconversion of rice straw into a soil-like substrate (SLS) by mushrooms and worms has been studied. The results showed that rice straw could be treated better by aerobic fermentation and succeeding growth of mushrooms Pleurotus ostreatus. In this process the total content of lignocellulose in the straw was removed by 37.74%. Furthermore, 46.68 g (fresh weight) of mushrooms could be produced from 100.0 g (dry weight) of rice straw. During the conversion of rice straw into a starting SLS by mushrooms and worms, the matter loss was 77.31%. The lettuce has been planted in the SLS and the yield when lettuce was cultivated on the SLS (8.77gm-2day-1) was comparable to the yield obtained on the nutrient solution. In addition, the silicon in the SLS ash can reach upto 32% and the circulation of it is expected during the growth of rice.

Evaluation energy efficiency of bioconversion knot rejects to ethanol in comparison to other thermochemically pretreated biomass.

PubMed

Wang, Zhaojiang; Qin, Menghua; Zhu, J Y; Tian, Guoyu; Li, Zongquan

2013-02-01

Rejects from sulfite pulp mill that otherwise would be disposed of by incineration were converted to ethanol by a combined physical-biological process that was comprised of physical refining and simultaneous saccharification and fermentation (SSF). The energy efficiency was evaluated with comparison to thermochemically pretreated biomass, such as those pretreated by dilute acid (DA) and sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL). It was observed that the structure deconstruction of rejects by physical refining was indispensable to effective bioconversion but more energy intensive than that of thermochemically pretreated biomass. Fortunately, the energy consumption was compensated by the reduced enzyme dosage and the elevated ethanol yield. Furthermore, adjustment of disk-plates gap led to reduction in energy consumption with negligible influence on ethanol yield. In this context, energy efficiency up to 717.7% was achieved for rejects, much higher than that of SPORL sample (283.7%) and DA sample (152.8%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Isolation and Characterization of a Novel Rebaudioside M Isomer from a Bioconversion Reaction of Rebaudioside A and NMR Comparison Studies of Rebaudioside M Isolated from Stevia rebaudiana Bertoni and Stevia rebaudiana Morita

PubMed Central

Prakash, Indra; Bunders, Cynthia; Devkota, Krishna P.; Charan, Romila D.; Ramirez, Catherine; Priedemann, Christopher; Markosyan, Avetik

2014-01-01

A minor product, rebaudioside M2 (2), from the bioconversion reaction of rebaudioside A (4) to rebaudioside D (3), was isolated and the complete structure of the novel steviol glycoside was determined. Rebaudioside M2 (2) is considered an isomer of rebaudioside M (1) and contains a relatively rare 1→6 sugar linkage. It was isolated and characterized with NMR (1H, 13C, COSY, HSQC-DEPT, HMBC, 1D-TOCSY, and NOESY) and mass spectral data. Additionally, we emphasize the importance of 1D and 2D NMR techniques when identifying complex steviol glycosides. Numerous NMR spectroscopy studies of rebaudioside M (1), rebaudioside D (3), and mixture of 1 and 3 led to the discovery that SG17 which was previously reported in literature, is a mixture of rebaudioside D (3), rebaudioside M (1), and possibly other related steviol glycosides. PMID:24970220

Bioaugmentation with Clostridium tyrobutyricum to improve butyric acid production through direct rice straw bioconversion.

PubMed

Chi, Xue; Li, Jianzheng; Wang, Xin; Zhang, Yafei; Leu, Shao-Yuan; Wang, Ying

2018-05-02

One-pot bioconversion is an economically attractive biorefinery strategy to reduce enzyme consumption. Direct conversion of lignocellulosic biomass for butyric acid production is still challenging because of competition among microorganisms. In a consolidated hydrolysis/fermentation bioprocessing (CBP) the microbial structure may eventually prefer the production of caproic acid rather than butyric acid production. This paper presents a new bioaugmentation approach for high butyric acid production from rice straw. By dosing 0.03 g/L of Clostridium tyrobutyricum ATCC 25755 in the CBP, an increase of 226% higher butyric acid was yielded. The selectivity and concentration also increased to 60.7% and 18.05 g/L, respectively. DNA-sequencing confirmed the shift of bacterial community in the augmented CBP. Butyric acid producer was enriched in the bioaugmented bacterial community and the bacteria related to long chain acids production was degenerated. The findings may be useful in future research and process design to enhance productivity of desired bio-products. Copyright © 2018 Elsevier Ltd. All rights reserved.

Isolation and Characterization of a Human Intestinal Bacterium Eggerthella sp. AUH-JLD49s for the Conversion of (-)-3'-Desmethylarctigenin.

PubMed

Wang, Ye; Yu, Fei; Liu, Ming-Yue; Zhao, Yi-Kai; Wang, Dong-Ming; Hao, Qing-Hong; Wang, Xiu-Ling

2017-05-24

Arctiin is the most abundant bioactive compound contained in the Arctium lappa plant. In our previous study, we isolated one single bacterium capable of bioconverting arctigenin, an aglycone of arctiin, to 3'-desmethylarctigenin (3'-DMAG) solely. However, to date, a specific bacterium capable of producing other arctiin metabolites has not been reported. In this study, we isolated one single bacterium, which we named Eggerthella sp. AUH-JLD49s, capable of bioconverting 3'-DMAG under anaerobic conditions. The metabolite of 3'-DMAG by strain AUH-JLD49s was identified as 3'-desmethyl-4'-dehydroxyarctigenin (DMDH-AG) based on electrospray ionization mass spectrometry (ESI-MS) and 1 H and 13 C nuclear magnetic resonance spectroscopy. The bioconversion kinetics and bioconversion capacity of strain AUH-JLD49s were investigated. In addition, the metabolite DMDH-AG showed an inhibitory effect on cell growth of human colon cancer cell line HCT116 and human breast cancer cell line MDA-MB-231.

Analytical Methods for Biomass Characterization during Pretreatment and Bioconversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pu, Yunqiao; Meng, Xianzhi; Yoo, Chang Geun

2016-01-01

Lignocellulosic biomass has been introduced as a promising resource for alternative fuels and chemicals because of its abundance and complement for petroleum resources. Biomass is a complex biopolymer and its compositional and structural characteristics largely vary depending on its species as well as growth environments. Because of complexity and variety of biomass, understanding its physicochemical characteristics is a key for effective biomass utilization. Characterization of biomass does not only provide critical information of biomass during pretreatment and bioconversion, but also give valuable insights on how to utilize the biomass. For better understanding biomass characteristics, good grasp and proper selection ofmore » analytical methods are necessary. This chapter introduces existing analytical approaches that are widely employed for biomass characterization during biomass pretreatment and conversion process. Diverse analytical methods using Fourier transform infrared (FTIR) spectroscopy, gel permeation chromatography (GPC), and nuclear magnetic resonance (NMR) spectroscopy for biomass characterization are reviewed. In addition, biomass accessibility methods by analyzing surface properties of biomass are also summarized in this chapter.« less

Life cycle evaluation of emerging lignocellulosic ethanol conversion technologies.

PubMed

Spatari, Sabrina; Bagley, David M; MacLean, Heather L

2010-01-01

Lignocellulosic ethanol holds promise for addressing climate change and energy security issues associated with personal transportation through lowering the fuel mixes' carbon intensity and petroleum demand. We compare the technological features and life cycle environmental impacts of near- and mid-term ethanol bioconversion technologies in the United States. Key uncertainties in the major processes: pre-treatment, hydrolysis, and fermentation are evaluated. The potential to reduce fossil energy use and greenhouse gas (GHG) emissions varies among bioconversion processes, although all options studied are considerably more attractive than gasoline. Anticipated future performance is found to be considerably more attractive than that published in the literature as being achieved to date. Electricity co-product credits are important in characterizing the GHG impacts of different ethanol production pathways; however, in the absence of near-term liquid transportation fuel alternatives to gasoline, optimizing ethanol facilities to produce ethanol (as opposed to co-products) is important for reducing the carbon intensity of the road transportation sector and for energy security.

Yeast metabolic engineering for hemicellulosic ethanol production

Treesearch

Jennifer Van Vleet; Thomas W. Jeffries

2009-01-01

Efficient fermentation of hemicellulosic sugars is critical for the bioconversion of lignocellulosics to ethanol. Efficient sugar uptake through the heterologous expression of yeast and fungal xylose/glucose transporters can improve fermentation if other metabolic steps are not rate limiting. Rectification of cofactor imbalances through heterologous expression of...

The acid-tolerant L-arabinose isomerase from the mesophilic Shewanella sp. ANA-3 is highly active at low temperatures

PubMed Central

2011-01-01

Background L-arabinose isomerases catalyse the isomerization of L-arabinose into L-ribulose at insight biological systems. At industrial scale of this enzyme is used for the bioconversion of D-galactose into D-tagatose which has many applications in pharmaceutical and agro-food industries. The isomerization reaction is thermodynamically equilibrated, and therefore the bioconversion rates is shifted towards tagatose when the temperature is increased. Moreover, to prevent secondary reactions it will be of interest to operate at low pH. The profitability of this D-tagatose production process is mainly related to the use of lactose as cheaper raw material. In many dairy products it will be interesting to produce D-tagatose during storage. This requires an efficient L-arabinose isomerase acting at low temperature and pH values. Results The gene encoding the L-arabinose isomerase from Shewanella sp. ANA-3 was cloned and overexpressed in Escherichia coli. The purified protein has a tetrameric arrangement composed by four identical 55 kDa subunits. The biochemical characterization of this enzyme showed that it was distinguishable by its maximal activity at low temperatures comprised between 15-35°C. Interestingly, this biocatalyst preserves more than 85% of its activity in a broad range of temperatures from 4.0 to 45°C. Shewanella sp. ANA-3 L-arabinose isomerase was also optimally active at pH 5.5-6.5 and maintained over 80% of its activity at large pH values from 4.0 to 8.5. Furthermore, this enzyme exhibited a weak requirement for metallic ions for its activity evaluated at 0.6 mM Mn2+. Stability studies showed that this protein is highly stable mainly at low temperature and pH values. Remarkably, T268K mutation clearly enhances the enzyme stability at low pH values. Use of this L-arabinose isomerase for D-tagatose production allows the achievement of attractive bioconversion rates of 16% at 4°C and 34% at 35°C. Conclusions Here we reported the purification and the biochemical characterization of the novel Shewanella sp. ANA-3 L-arabinose isomerase. Determination of the biochemical properties demonstrated that this enzyme was highly active at low temperatures. The generated T268K mutant displays an increase of the enzyme stability essentially at low pH. These features seem to be very attractive for the bioconversion of D-galactose into D-tagatose at low temperature which is very interesting from industrial point of view. PMID:22074172

Lactobacillus acidophilus Metabolizes Dietary Plant Glucosides and Externalizes Their Bioactive Phytochemicals.

PubMed

Theilmann, Mia C; Goh, Yong Jun; Nielsen, Kristian Fog; Klaenhammer, Todd R; Barrangou, Rodolphe; Abou Hachem, Maher

2017-11-21

Therapeutically active glycosylated phytochemicals are ubiquitous in the human diet. The human gut microbiota (HGM) modulates the bioactivities of these compounds, which consequently affect host physiology and microbiota composition. Despite a significant impact on human health, the key players and the underpinning mechanisms of this interplay remain uncharacterized. Here, we demonstrate the growth of Lactobacillus acidophilus on mono- and diglucosyl dietary plant glycosides (PGs) possessing small aromatic aglycones. Transcriptional analysis revealed the upregulation of host interaction genes and identified two loci that encode phosphotransferase system (PTS) transporters and phospho-β-glucosidases, which mediate the uptake and deglucosylation of these compounds, respectively. Inactivating these transport and hydrolysis genes abolished or severely reduced growth on PG, establishing the specificity of the loci to distinct groups of PGs. Following intracellular deglucosylation, the aglycones of PGs are externalized, rendering them available for absorption by the host or for further modification by other microbiota taxa. The PG utilization loci are conserved in L. acidophilus and closely related lactobacilli, in correlation with versatile growth on these compounds. Growth on the tested PG appeared more common among human gut lactobacilli than among counterparts from other ecologic niches. The PGs that supported the growth of L. acidophilus were utilized poorly or not at all by other common HGM strains, underscoring the metabolic specialization of L. acidophilus These findings highlight the role of human gut L. acidophilus and select lactobacilli in the bioconversion of glycoconjugated phytochemicals, which is likely to have an important impact on the HGM and human host. IMPORTANCE Thousands of therapeutically active plant-derived compounds are widely present in berries, fruits, nuts, and beverages like tea and wine. The bioactivity and bioavailability of these compounds, which are typically glycosylated, are altered by microbial bioconversions in the human gut. Remarkably, little is known about the bioconversion of PGs by the gut microbial community, despite the significance of this metabolic facet to human health. Our work provides the first molecular insights into the metabolic routes of diet relevant and therapeutically active PGs by Lactobacillus acidophilus and related human gut lactobacilli. This taxonomic group is adept at metabolizing the glucoside moieties of select PG and externalizes their aglycones. The study highlights an important role of lactobacilli in the bioconversion of dietary PG and presents a framework from which to derive molecular insights into their metabolism by members of the human gut microbiota. Copyright © 2017 Theilmann et al.

Switchgrass biomass composition traits and their effects on its digestion by ruminants and bioconversion to ethanol

USDA-ARS?s Scientific Manuscript database

Six generations of divergent breeding in switchgrass (Panicum virgatum L.) for forage in vitro digestibility (IVDMD) resulted in significant changes in 20 biomass composition traits. Stepwise multi-regression was used to determine which of the 20 composition traits had largest significant effects on...

A Comparative Study of Dilute acid and Ionic Liquid Pretreatment of Biomass and Model Lignocellulosics

USDA-ARS?s Scientific Manuscript database

Lignocellulosic biomass has the great potential to serve as the low cost and abundant feedstock for bioconversion into fermentable sugars, which can be further utilized for biofuel production. However, high lignin content, crystalline cellulose structure and the presence of ester linkages between l...

Fungal Bioconversion of Bio-Solids and Chicken Manure to Increase Soil Quality

USDA-ARS?s Scientific Manuscript database

The utilization of agro-chemical products such as pesticides and fertilizers has allowed the increase in food production. Poultry manure and manure from different animals have been used as alternative to improve soil quality, and therefore, helped increase crop production. Nevertheless, removal of t...

Biological Life Support Systems

NASA Technical Reports Server (NTRS)

1997-01-01

Session MP2 includes short reports on: (1) Crew Regenerative Life Support in Long Duration Space Missions; (2) Bioconversion Systems for Food and Water on Long Term Space Missions; (3) Novel Laboratory Approaches to Multi-purpose Aquatic Biogenerative Closed-Loop Food Production Systems; and (4) Artificial Neural Network Derived Plant Growth Models.

Assessing the specific energy consumption and physical properties of comminuted Douglas-fir chips for bioconversion

Treesearch

Yalan Liu; Jinwu Wang; Michael P. Wolcott

2016-01-01

Size reduction homogenizes the bulk biomass and facilitates downstream feedstock handling, transportation, and storage. Effects of feeding rate, mill-type (hammer and knife mill), screen size, and moisture content on comminution energy consumption of commercial Douglas-fir (Pseudotsuga menziesii) pulp chips were quantified. The resulting particles...

Pretreatment of microbial sludges

DOEpatents

Rivard, Christopher J.; Nagle, Nicholas J.

1995-01-01

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Biomass Feedstocks | Bioenergy | NREL

Science.gov Websites

publications. Photo of a group of smiling men and women posing in a casual office setting. Thermochemical xylose) from bioconversion of pelleted and non-pelleted corn stover (CS), Switchgrass (SWG), and Hybrid Variety on the x-axis, showing Non-pelleted (yellow) and Pelleted (orange) results for five groups of data

Lignosulfonate-mediated cellulase adsorption: enhanced enzymatic saccharification of lignocellulose through weakening nonproductive binding to lignin

Treesearch

Zhaojiang Wang; JY Zhu; Yingjuan Fu; Menghua Qin; Zhiyong Shao; Jungang Jiang; Fang Yang

2013-01-01

Thermochemical pretreatment of lignocellulose is crucial to bioconversion in the fields of biorefinery and biofuels. However, the enzyme inhibitors in pretreatment hydrolysate make solid substrate washing and hydrolysate detoxification indispensable prior to enzymatic hydrolysis. Sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) is a relatively...

Bioethanol production from corn stover using aqueous ammonia pretreatment and two-phase simultaneouos saccharification and fermentation (TPSSF)

USDA-ARS?s Scientific Manuscript database

An integrated bioconversion process was developed to convert corn-stover derived pentose and hexose to ethanol effectively. In this study, corn stover was pretreated by soaking in aqueous ammonia (SAA), which resulted in high retention of glucan (~100%) and xylan (>80%) in the solids. The pretreated...

UPTAKE, DISTRIBUTION, AND BIOCONVERSION OF FLUORESCENT LIPID ANALOGS IN THE OYSTER PROTOZOAN PARASITE, PERKINSUS MARINUS

EPA Science Inventory

It has been established that host lipids play a unique role for long term survival and life cycle completion in endogenous parasites. Parasites exploit fatty acids and lipids from the host, not only for membrane synthesis, but also for modification of their surface integrity to a...

Pretreatment and fractionation of wheat straw for production of fuel ethanol and value-added co-products in a biorefinery

USDA-ARS?s Scientific Manuscript database

An integrated process has been developed for a wheat straw biorefinery. In this process wheat straw was pretreated by soaking in aqueous ammonia (SAA), which extensively removed lignin but preserved high percentages of the carbohydrate fractions for subsequent bioconversion. The pretreatment condi...

Agricultural residues and energy crops as potentially economical and novel substrates for microbial production of butanol (a biofuel)

USDA-ARS?s Scientific Manuscript database

This review describes production of acetone butanol ethanol (ABE) from a variety of agricultural residues and energy crops employing biochemical or fermentation processes. A number of organisms are available for this bioconversion including Clostridium beijerinckii P260, C. beijerinckii BA101, C. a...

Microbial Production of Xylitol from L-arabinose by Metabolically Engineered Escherichia coli

USDA-ARS?s Scientific Manuscript database

An Escherichia coli strain, ZUC99(pATX210), which can produce xylitol from L-arabinose at a high yield has been created by introducing a new bioconversion pathway into cells. This pathway consists of three enzymes: L-arabinose isomerase, which converts L-arabinose to L-ribulose; D-psicose 3-epimer...

Metabolic engineering for improved fermentation of pentoses by yeasts

Treesearch

T. W. Jeffries; Jin. Y.-S.

2004-01-01

The fermentation of xylose is essential for the bioconversion of lignocellulose to fuels and chemicals, but wild-type strains of Saccharomyces cerevisiae do not metabolize xylose, so researchers have engineered xylose metabolism in this yeast. Glucose transporters mediate xylose uptake, but no transporter specific for xylose has yet been identified. Over-expressing...

Pretreatment of microbial sludges

DOEpatents

Rivard, C.J.; Nagle, N.J.

1995-01-10

Methods are described for pretreating microbial sludges to break cells and disrupt organic matter. One method involves the use of sonication, and another method involves the use of shear forces. The pretreatment of sludge enhances bioconversion of the organic fraction. This allows for efficient dewatering of the sludge and reduces the cost for final disposal of the waste.

Bioconversion of 7-hydroxyflavanone: isolation, characterization and bioactivity evaluation of twenty-one phase I and phase II microbial metaboites

USDA-ARS?s Scientific Manuscript database

Microbial metabolism of 7-hydroxyflavanone (1) with fungal culture Cunninghamella blakesleeana (ATCC 8688a), yielded flavanone 7-sulfate (2), 7,4’-dihydroxyflavanone (3), 6,7-dihydroxyflavanone (4), 6-hydroxyflavanone 7-sulfate (5), and 7-hydroxyflavanone 6-sulfate (6). Mortierella zonata (ATCC 1330...

Cellulosic butanol production from agricultural biomass and residues: Recent advances in technology

USDA-ARS?s Scientific Manuscript database

This chapter details the recent advances made on bioconversion of lignocellulosic biomass to butanol, a superior biofuel that can be used in internal combustion engines or transportation industry. It should be noted that butanol producing cultures cannot tolerate or produce more than 20-30 g/L of ac...

Optimal Production of 7,10-dihydroxy-8(E)-hexadecenoic Acid from Palmitoleic Acid by Pseudomonas aeruginosa PR3

USDA-ARS?s Scientific Manuscript database

The hydroxylation of unsaturated fatty acids by bacterial strains is one type of value-adding bioconversion process. This process generates new hydroxy fatty acids (HFA) carrying special properties such as higher viscosity and reactivity compared with normal fatty acids. Among microbial strains te...

Pilot-scale demonstration of SPORL for bioconversion of lodgepole pine to bioethanol and lignosulfonate

Treesearch

Haifeng Zhou; Junyong Zhu; Roland Gleisner; Xueqing Qiu; Eric Horn; Jose Negron

2016-01-01

The process sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) has been the focus of this study. Pilot-scale (50 kg) pretreatment of wood chips of lodgepole pine (Pinus contorta Douglas ex Loudon) killed by mountain pine beetle (Dendroctonus ponderosae Hopkins) were conducted at 165°C...

Sulfite pretreatment (SPORL) for robust enzymatic saccharification of spruce and red pine

Treesearch

J.Y. Zhu; X.J. Pan; G.S. Wang; R. Gleisner

2009-01-01

This study established a novel process using sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust and efficient bioconversion of softwoods. The process consists of sulfite treatment of wood chips under acidic conditions followed by mechanical size reduction using disk refining. The results indicated that after the SPORL pretreatment of...

Second generation bioethanol production from Saccharum spontaneum L. ssp. aegyptiacum (Willd.) Hack.

Treesearch

Danilo Scordia; Salvatore L. Consentino; Thomas W. Jeffries

2010-01-01

Saccharum (Saccharum spontaneum L. ssp. aegyptiacum (Willd.) Hack.), is a rapidly growing, wide ranging high-yield perennial, suitable for second generation bioethanol production. This study evaluated oxalic acid as a pretreatment for bioconversion. Overall sugar yields, sugar degradation products, enzymatic glucan hydrolysis and ethanol production were studied as...

Ethanol and thermotolerance in the bioconversion of xylose by yeasts

Treesearch

Thomas W. Jeffries; Yong-Su Jin

2000-01-01

The mechanisms underlying ethanol and heat tolerance are complex. Many different genes are involved, and the exact basis is not fully understood. The integrity of cytoplasmic and mitochondrial membranes is critical to maintain proton gradients for metabolic energy and nutrient uptake. Heat and ethanol stress adversely affect membrane integrity. These factors are...

Biocatalytic material comprising multilayer enzyme coated fiber

DOEpatents

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

The present invention relates generally to high stability, high activity biocatalytic materials and processes for using the same. The materials comprise enzyme aggregate coatings having high biocatalytic activity and stability useful in heterogeneous environment. These new materials provide a new biocatalytic immobilized enzyme system with applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Biological conversion system

DOEpatents

Scott, C.D.

A system for bioconversion of organic material comprises a primary bioreactor column wherein a biological active agent (zymomonas mobilis) converts the organic material (sugar) to a product (alcohol), a rejuvenator column wherein the biological activity of said biological active agent is enhanced, and means for circulating said biological active agent between said primary bioreactor column and said rejuvenator column.

Biodegradation and bioconversion of coals by fungi. Quarterly progress report No. 1, October 1-December 31, 1985. [Candida sp. and T. versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, B.

1985-01-01

Following a month-long start-up period during which the principal investigator traveled to several sites of lignite outcrops to collect samples, efforts were begun to isolate new strains of coal-bioconverting fungal strains. Out of about thirty different organisms isolated from weathered samples of three different types of lignite, three isolates exhibited biosolubilization of the one lignite tested to date. These organisms have not yet been identified but they appear to be new strains of lignite-degrading fungi. We have observed that degree of biosolubilization varies among apparently similar samples of the same lignite. Weathered lignite is more readily solubilized than is previouslymore » unexposed lignite, but even tests on weathered coal have not been consistently repeatable. We have begun experiments designed to identify one or more factors of weathering which render coal more readily attacked by fungi. We hope to establish methods whereby consistently repeatable assays can be performed on bioconversion of coals. 2 refs., 1 fig., 1 tab.« less

Methanogenic degradation of toilet-paper cellulose upon sewage treatment in an anaerobic membrane bioreactor at room temperature.

PubMed

Chen, Rong; Nie, Yulun; Kato, Hiroyuki; Wu, Jiang; Utashiro, Tetsuya; Lu, Jianbo; Yue, Shangchao; Jiang, Hongyu; Zhang, Lu; Li, Yu-You

2017-03-01

Toilet-paper cellulose with rich but refractory carbon sources, are the main insoluble COD fractions in sewage. An anaerobic membrane bioreactor (AnMBR) was configured for sewage treatment at room temperature and its performance on methanogenic degradation of toilet paper was highlighted. The results showed, high organic removal (95%), high methane conversion (90%) and low sludge yield (0.08gVSS/gCOD) were achieved in the AnMBR. Toilet-paper cellulose was fully biodegraded without accumulation in the mixed liquor and membrane cake layer. Bioconversion efficiency of toilet paper approached 100% under a high organic loading rate (OLR) of 2.02gCOD/L/d and it could provide around 26% of total methane generation at most of OLRs. Long sludge retention time and co-digestion of insoluble/soluble COD fractions achieving mutualism of functional microorganisms, contributed to biodegradation of toilet-paper cellulose. Therefore the AnMBR successfully implemented simultaneously methanogenic bioconversion of toilet-paper cellulose and soluble COD in sewage at room temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional characterization of CYP52G3 from Aspergillus oryzae and its application for bioconversion and synthesis of hydroxyl flavanone and steroids.

PubMed

Uno, Tomohide; Yanase, Takeshi; Imaishi, Hiromasa

2017-05-01

Aspergillus oryzae is a fungus widely used in traditional Japanese fermentation industries. Cytochrome P450 (CYP) proteins are ubiquitously distributed in nature and display a broad range of enzymatic activities. A novel CYP52 (CYP52G3) gene was found in A. oryzae. In this study, we report the functional characterization of CYP52G3. The recombinant protein was expressed heterologously in Escherichia coli, and its membrane fraction isolated. CYP52G3 showed activities for 7-ethoxycoumarin and α-naphtoflavone. Furthermore, CYP52G3 hydroxylated flavanone at the 4' and 6 position and metabolized some hydroxyl-flavanones and steroids. Bioconversion experiments indicated that CYP52G3 could convert flavanone and testosterone in a synthetic medium. The conversion rates of flavanone and testosterone at 24 H were 50% and 70%, respectively. These results support that CYP52G3 could prove a useful enzyme for the efficient production of new compounds from flavonoids and steroids. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Metabolic engineering for improved microbial pentose fermentation.

PubMed

Fernandes, Sara; Murray, Patrick

2010-01-01

Global concern over the depletion of fossil fuel reserves, and the detrimental impact that combustion of these materials has on the environment, is focusing attention on initiatives to create sustainable approaches for the production and use of biofuels from various biomass substrates. The development of a low-cost, safe and eco-friendly process for the utilization of renewable resources to generate value-added products with biotechnological potential as well as robust microorganisms capable of efficient fermentation of all types of sugars are essential to underpin the economic production of biofuels from biomass feedstocks. Saccharomyces cerevisiae, the most established fermentation yeast used in large scale bioconversion strategies, does not however metabolise the pentose sugars, xylose and arabinose and bioengineering is required for introduction of efficient pentose metabolic pathways and pentose sugar transport proteins for bioconversion of these substrates. Our approach provided a basis for future experiments that may ultimately lead to the development of industrial S. cerevisiae strains engineered to express pentose metabolising proteins from thermophilic fungi living on decaying plant material and here we expand our original article and discuss the strategies implemented to improve pentose fermentation. © 2010 Landes Bioscience

Construction of a highly efficient Bacillus subtilis 168 whole-cell biocatalyst and its application in the production of L-ornithine.

PubMed

Wang, Meizhou; Xu, Meijuan; Rao, Zhiming; Yang, Taowei; Zhang, Xian

2015-11-01

L-Ornithine, a non-protein amino acid, is usually extracted from hydrolyzed protein as well as produced by microbial fermentation. Here, we focus on a highly efficient whole-cell biocatalyst for the production of L-ornithine. The gene argI, encoding arginase, which catalyzes the hydrolysis of L-arginine to L-ornithine and urea, was cloned from Bacillus amyloliquefaciens B10-127 and expressed in GRAS strain Bacillus subtilis 168. The recombinant strain exhibited an arginase activity of 21.9 U/mg, which is 26.7 times that of wild B. subtilis 168. The optimal pH and temperature of the purified recombinant arginase were 10.0 and 40 °C, respectively. In addition, the recombinant arginase exhibited a strong Mn(2+) preference. When using whole-cell biocatalyst-based bioconversion, a hyper L-ornithine production of 356.9 g/L was achieved with a fed-batch strategy in a 5-L reactor within 12 h. This whole-cell bioconversion study demonstrates an environmentally friendly strategy for L-ornithine production in industry.

Development of the University of Washington Biofuels and Biobased Chemicals Process Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gustafson, Richard

2014-02-04

The funding from this research grant enabled us to design and build a bioconversion steam explosion reactor and ancillary equipment such as a high pressure boiler and a fermenter to support the bioconversion process research. This equipment has been in constant use since its installation in 2012. Following are research projects that it has supported: • Investigation of novel chip production method in biofuels production • Investigation of biomass refining following steam explosion • Several studies on use of different biomass feedstocks • Investigation of biomass moisture content on pretreatment efficacy. • Development of novel instruments for biorefinery process controlmore » Having this equipment was also instrumental in the University of Washington receiving a $40 million grant from the US Department of Agriculture for biofuels development as well as several other smaller grants. The research that is being done with the equipment from this grant will facilitate the establishment of a biofuels industry in the Pacific Northwest and enable the University of Washington to launch a substantial biofuels and bio-based product research program.« less

Quantifying pretreatment degradation compounds in solution and accumulated by cells during solids and yeast recycling in the Rapid Bioconversion with Integrated recycling Technology process using AFEX™ corn stover.

PubMed

Sarks, Cory; Higbee, Alan; Piotrowski, Jeff; Xue, Saisi; Coon, Joshua J; Sato, Trey K; Jin, Mingjie; Balan, Venkatesh; Dale, Bruce E

2016-04-01

Effects of degradation products (low molecular weight compounds produced during pretreatment) on the microbes used in the RaBIT (Rapid Bioconversion with Integrated recycling Technology) process that reduces enzyme usage up to 40% by efficient enzyme recycling were studied. Chemical genomic profiling was performed, showing no yeast response differences in hydrolysates produced during RaBIT enzymatic hydrolysis. Concentrations of degradation products in solution were quantified after different enzymatic hydrolysis cycles and fermentation cycles. Intracellular degradation product concentrations were also measured following fermentation. Degradation product concentrations in hydrolysate did not change between RaBIT enzymatic hydrolysis cycles; the cell population retained its ability to oxidize/reduce (detoxify) aldehydes over five RaBIT fermentation cycles; and degradation products accumulated within or on the cells as RaBIT fermentation cycles increased. Synthetic hydrolysate was used to confirm that pretreatment degradation products are the sole cause of decreased xylose consumption during RaBIT fermentations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Genetic improvement of native xylose-fermenting yeasts for ethanol production.

PubMed

Harner, Nicole K; Wen, Xin; Bajwa, Paramjit K; Austin, Glen D; Ho, Chi-Yip; Habash, Marc B; Trevors, Jack T; Lee, Hung

2015-01-01

Lignocellulosic substrates are the largest source of fermentable sugars for bioconversion to fuel ethanol and other valuable compounds. To improve the economics of biomass conversion, it is essential that all sugars in potential hydrolysates be converted efficiently into the desired product(s). While hexoses are fermented into ethanol and some high-value chemicals, the bioconversion of pentoses in hydrolysates remains inefficient. This remains one of the key challenges in lignocellulosic biomass conversion. Native pentose-fermenting yeasts can ferment both glucose and xylose in lignocellulosic biomass to ethanol. However, they perform poorly in the presence of hydrolysate inhibitors, exhibit low ethanol tolerance and glucose repression, and ferment pentoses less efficiently than the main hexoses glucose and mannose. This paper reviews classical and molecular strain improvement strategies applied to native pentose-fermenting yeasts for improved ethanol production from xylose and lignocellulosic substrates. We focus on Pachysolen tannophilus, Scheffersomyces (Candida) shehatae, Scheffersomyces (Pichia) stipitis, and Spathaspora passalidarum which are good ethanol producers among the native xylose-fermenting yeasts. Strains obtained thus far are not robust enough for efficient ethanol production from lignocellulosic hydrolysates and can benefit from further improvements.

The Influence of Sugar Cane Bagasse Type and Its Particle Size on Xylose Production and Xylose-to-Xylitol Bioconversion with the Yeast Debaryomyces hansenii.

PubMed

Aghcheh, Razieh Karimi; Bonakdarpour, Babak; Ashtiani, Farzin Zokaee

2016-11-01

In the present study, the effect of the type of sugar cane bagasse (non-depithed or depithed) and its particle size on the production of xylose and its subsequent fermentation to xylitol by Debaryomyces hansenii CBS767 was investigated using a full factorial experimental design. It was found that the particle size range and whether bagasse was depithed or not had a significant effect on the concentration and yield of xylose in the resulting hemicellulose hydrolysate. Depithed bagasse resulted in higher xylose concentrations compared to non-depithed bagasse. The corresponding detoxified hemicellulose hydrolysates were used as fermentation media for the production of xylitol. The hemicellulose hydrolysate prepared from depithed bagasse also yielded meaningfully higher xylitol fermentation rates compared to non-depithed bagasse. However, in the case of non-depithed bagasse, the hemicellulose hydrolysate prepared from larger particle size range resulted in higher xylitol fermentation rates, whereas the effect in the case of non-depithed bagasse was not pronounced. Therefore, depithing of bagasse is an advantageous pretreatment when it is to be employed in bioconversion processes.

Pilot-scale bioconversion of rice and sunflower agro-residues into medicinal mushrooms and laccase enzymes through solid-state fermentation with Ganoderma lucidum.

PubMed

Postemsky, P D; Bidegain, M A; González-Matute, R; Figlas, N D; Cubitto, M A

2017-05-01

Solid-state fermentation was evaluated at the pilot-scale for the bioconversion and valorization of rice husks and straw (RSH), or sunflower seed hulls (SSH), into medicinal mushrooms and crude extracts, with laccase activity. The average mushroom yield was 56kg dry weight per ton of agro-residues. Laccase activity in crude aqueous extracts showed its maximum value of 10,927Ukg -1 in RSH (day 10, Exudate phase) and 16,442Ukg -1 in SSH (day 5, Full colonization phase), the activity at the Residual substrate phase being 511Ukg -1 in RSH and 803Ukg -1 in SSH, respectively. Crude extracts obtained with various protocols revealed differences in the extraction yields. Lyophilization followed by storage at 4°C allowed the preservation of laccase activity for more than one month. It is proposed that standard mushroom farms could increase their profits by obtaining laccase as a byproduct during the gaps in mycelium running. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: life cycle assessment.

PubMed

Budsberg, Erik; Crawford, Jordan T; Morgan, Hannah; Chin, Wei Shan; Bura, Renata; Gustafson, Rick

2016-01-01

Bio-jet fuels compatible with current aviation infrastructure are needed as an alternative to petroleum-based jet fuel to lower greenhouse gas emissions and reduce dependence on fossil fuels. Cradle to grave life cycle analysis is used to investigate the global warming potential and fossil fuel use of converting poplar biomass to drop-in bio-jet fuel via a novel bioconversion platform. Unique to the biorefinery designs in this research is an acetogen fermentation step. Following dilute acid pretreatment and enzymatic hydrolysis, poplar biomass is fermented to acetic acid and then distilled, hydroprocessed, and oligomerized to jet fuel. Natural gas steam reforming and lignin gasification are proposed to meet hydrogen demands at the biorefineries. Separate well to wake simulations are performed using the hydrogen production processes to obtain life cycle data. Both biorefinery designs are assessed using natural gas and hog fuel to meet excess heat demands. Global warming potential of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from CO2 equivalences of 60 to 66 and 32 to 73 g MJ(-1), respectively. Fossil fuel usage of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from 0.78 to 0.84 and 0.71 to 1.0 MJ MJ(-1), respectively. Lower values for each impact category result from using hog fuel to meet excess heat/steam demands. Higher values result from using natural gas to meet the excess heat demands. Bio-jet fuels produced from the bioconversion of poplar biomass reduce the global warming potential and fossil fuel use compared with petroleum-based jet fuel. Production of hydrogen is identified as a major source of greenhouse gas emissions and fossil fuel use in both the natural gas steam reforming and lignin gasification bio-jet simulations. Using hog fuel instead of natural gas to meet heat demands can help lower the global warming potential and fossil fuel use at the biorefineries.

Isolation and characterization of Bacillus subtilis strain BY-3, a thermophilic and efficient cellulase-producing bacterium on untreated plant biomass.

PubMed

Meng, F; Ma, L; Ji, S; Yang, W; Cao, B

2014-09-01

Bioconversion of biomass, particularly crop wastes, into biofuels is being developed as an alternative approach in meeting the high energy demand. In this study, a thermophilic bacterial strain BY-3 that exhibits cellulolytic potential was isolated from faecal samples of Tibetan pigs; this strain was identified as Bacillus subtilis. The strain can produce cellulase when grown on various substrates, including carboxymethyl cellulose, rice straw, corn stover, soluble starch and wheat bran. The maximum cellulase activity of the strain was up to 4·323 ± 0·065 U ml(-1) when cultivated in the medium containing corn stover (30 g l(-1) ) for 24 h. The results demonstrated that corn stover is the most suitable substrate for cellulase production by the strain BY-3. The crude cellulase of strain BY-3 was most active at pH 5·5 and 60°C, and the enzyme in acetate buffer (50 mmol l(-1) ) demonstrated a good stability at 60°C for at least 1 h. The crude cellulase exhibited a strong antibacterial activity against Staphylococcus aureus. The strain can be used in cost-efficient cellulase production for bioconversion of agricultural residual biomass into biofuels. The increased consumption of fossil fuels has caused serious energy crisis and environmental problem. Thus, an alternative energy source is necessary. Bioconversion of biomass, particularly agricultural residuals, into value-added bioproducts, such as biofuels and chemical solvents, has received considerable attention. In this study, the newly isolated thermophilic Bacillus subtilis strain BY-3 produces cellulase efficiently with the use of untreated corn stover as a sole carbon source. This strain possesses the thermostable cellulase that is active with diverse crop wastes with a broad pH range and is a highly promising candidate for agricultural waste management. © 2014 The Society for Applied Microbiology.

Combinatorial pretreatment and fermentation optimization enabled a record yield on lignin bioconversion.

PubMed

Liu, Zhi-Hua; Xie, Shangxian; Lin, Furong; Jin, Mingjie; Yuan, Joshua S

2018-01-01

Lignin valorization has recently been considered to be an essential process for sustainable and cost-effective biorefineries. Lignin represents a potential new feedstock for value-added products. Oleaginous bacteria such as Rhodococcus opacus can produce intracellular lipids from biodegradation of aromatic substrates. These lipids can be used for biofuel production, which can potentially replace petroleum-derived chemicals. However, the low reactivity of lignin produced from pretreatment and the underdeveloped fermentation technology hindered lignin bioconversion to lipids. In this study, combinatorial pretreatment with an optimized fermentation strategy was evaluated to improve lignin valorization into lipids using R. opacus PD630. As opposed to single pretreatment, combinatorial pretreatment produced a 12.8-75.6% higher lipid concentration in fermentation using lignin as the carbon source. Gas chromatography-mass spectrometry analysis showed that combinatorial pretreatment released more aromatic monomers, which could be more readily utilized by lignin-degrading strains. Three detoxification strategies were used to remove potential inhibitors produced from pretreatment. After heating detoxification of the lignin stream, the lipid concentration further increased by 2.9-9.7%. Different fermentation strategies were evaluated in scale-up lipid fermentation using a 2.0-l fermenter. With laccase treatment of the lignin stream produced from combinatorial pretreatment, the highest cell dry weight and lipid concentration were 10.1 and 1.83 g/l, respectively, in fed-batch fermentation, with a total soluble substrate concentration of 40 g/l. The improvement of the lipid fermentation performance may have resulted from lignin depolymerization by the combinatorial pretreatment and laccase treatment, reduced inhibition effects by fed-batch fermentation, adequate oxygen supply, and an accurate pH control in the fermenter. Overall, these results demonstrate that combinatorial pretreatment, together with fermentation optimization, favorably improves lipid production using lignin as the carbon source. Combinatorial pretreatment integrated with fed-batch fermentation was an effective strategy to improve the bioconversion of lignin into lipids, thus facilitating lignin valorization in biorefineries.

Simultaneous bioconversion of barley straw to butanol and product recovery: use of concentrated sugar solution and process integration

USDA-ARS?s Scientific Manuscript database

As a result of increased gasoline prices, we focused on the production of butanol which contains more energy than ethanol on per gallon (or kg) basis from cellulosic agricultural biomass such as wheat straw using two different systems: i) separate hydrolysis, fermentation, and recovery (SHFR), and ...

Cofermentation of Glucose, Xylose, and Cellobiose by the Beetle-Associated Yeast Spathaspora passalidarum

Treesearch

Tanya M. Long; Yi-Kai Su; Jennifer Headman; Alan Higbee; Laura B. Willis; Thomas W. Jeffries

2012-01-01

Fermentation of cellulosic and hemicellulosic sugars from biomass could resolve food-versus-fuel conflicts inherent in the bioconversion of grains. However, the inability to coferment glucose and xylose is a major challenge to the economical use of lignocellulose as a feedstock. Simultaneous cofermentation of glucose, xylose, and cellobiose is problematic for most...

Quantitative predictions of bioconversion of aspen by dilute acid and SPORL pretreatments using a unified combined hydrolysis factor (CHF)

Treesearch

W. Zhu; Carl J. Houtman; J.Y. Zhu; Roland Gleisner; K.F. Chen

2012-01-01

A combined hydrolysis factor (CHF) was developed to predict xylan hydrolysis during pretreatments of native aspen (Populus tremuloides) wood chips. A natural extension of previously developed kinetic models allowed us to account for the effect of catalysts by dilute acid and two sulfite pretreatments at different pH values....

Evaluation energy efficiency of bioconversion knot rejects to ethanol in comparison to other thermochemically pretreated biomass

Treesearch

Zhaojiang Wang; Menghua Qin; J.Y. Zhu; Guoyu Tian; Zongquan Li

2013-01-01

Rejects from sulfite pulp mill that otherwise would be disposed of by incineration were converted to ethanol by a combined physical–biological process that was comprised of physical refining and simultaneous saccharification and fermentation (SSF). The energy efficiency was evaluated with comparison to thermochemically pretreated biomass, such as those pretreated by...

Genome sequence of the lignocellulose-bioconverting and xylose-fermenting yeast Pichia stipitis

Treesearch

Thomas W. Jeffries; Igor V. Grigroriev; Jane Grimwood; Jose M. Laplaza; Andrea Aerts; Asaf Salamov; Jeremy Schmutz; Erika Lindquist; Paramvir Dehal; Harris Shapiro; Yong-Su Jin; Volkmar Passoth; Paul M. Richardson

2007-01-01

Xylose is a major constituent of plant lignocellulose, and its fermentation is important for the bioconversion of plant biomass to fuels and chemicals. Pichia stipitis is a well-studied, native xylose-fermenting yeast. The mechanism and regulation of xylose metabolism in P. stipitis have been characterized and genes from P. stipitis have been used to engineer xylose...

Bioconversion of Cyanidin-3-Rutinoside to Cyanidin-3-Glucoside in Black Raspberry by Crude α-L-Rhamnosidase from Aspergillus Species.

PubMed

Lim, Taehwan; Jung, Hana; Hwang, Keum Taek

2015-11-01

Cyanidin-3-glucoside (C3G) has been known to be more bioavailable than cyanidin-3- rutinoside (C3R), the most abundant anthocyanin in black raspberry (Rubus occidentalis). The aim of this study was to enhance the bioavailability of anthocyanins in black raspberry by cleaving L-rhamnose in C3R using crude enzyme extracts (CEEs) from Aspergillus usamii KCTC 6956, A. awamori KCTC 60380, A. niger KCCM 11724, A. oryzae KCCM 12698, and A. kawachii KCCM 32819. The enzyme activities of the CEEs were determined by a spectrophotometric method using rho-nitrophenyl-rhamnopyranoside and rho-nitrophenyl-glucopyranoside. The CEE from A. usamii had the highest α-L-rhamnosidase activity with 2.73 U/ml at 60°C, followed by those from A. awamori and A. niger. When bioconversion of C3R to C3G in black raspberry was analyzed by HPLC-DAD, the CEEs from A. usamii and A. awamori hydrolyzed 95.7% and 95.6% of C3R to C3G, respectively, after 2 h incubation. The CEEs from A. kawachii and A. oryzae did not convert C3R to C3G in black raspberry.

Hydrogel Film-Immobilized Lactobacillus brevis RK03 for γ-Aminobutyric Acid Production

PubMed Central

Hsueh, Yi-Huang; Liaw, Wen-Chang; Kuo, Jen-Min; Deng, Chi-Shin

2017-01-01

Hydrogels of 2-hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) have been extensively studied for their use in biomedical and pharmaceutical applications owing to their nontoxic and highly hydrophilic characteristics. Recently, cells immobilized by HEMA/PEGDA hydrogels have also been studied for enhanced production in fermentation. Hydrogel films of HEMA/PEGDA copolymer were generated by Ultraviolet (UV)-initiated photopolymerization. The hydrogel films were used to immobilize viable Lactobacillus brevis RK03 cells for the bioconversion of monosodium glutamate (MSG) to γ-aminobutyric acid (GABA). The mechanical properties and fermentation yields of the L. brevis RK03 cells immobilized on polyacrylate hydrogel films with different monomeric formulations were investigated. Fermentation was carried out in 75 mL de Man, Rogosa and Sharpe (MRS) medium containing various concentrations of MSG. We found that HEMA (93%)/PEGDA (3%) hydrogels (sample H) maximized GABA production. The conversion rate of MSG to GABA reached a maximum value of 98.4% after 240 h. Bioconversion activity gradually declined after 420 h to 83.8% after five cycles of semi-continuous fermentation. Our results suggest that HEMA (93%)/PEGDA (3%) hydrogels have great potential for use in GABA production via semi-continuous fermentation. PMID:29099794

Characterization and enzymatic hydrolysis of wood from transgenic Pinus taeda engineered with syringyl lignin or reduced lignin content

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edmunds, Charles W.; Peralta, Perry; Kelley, Stephen S.

Softwood is an abundant resource; however, currently its utilization for bioconversion to obtain platform sugars is limited. Pinus taeda trees which were genetically modified to either produce S lignin or to decrease lignin content were characterized with a suite of analytic techniques. Syringyl lignin was visualized in the secondary xylem of one genetic line with Maule staining. Solid-state nuclear magnetic resonance identified the S lignin units were coupled into the lignin through β-O-4 linkages, and thioacidolysis measured approximately 13% S lignin content in the same sample. Reductions of the lignin of as much as 33% were observed in the transgenics.more » To better understand how these modifications affect bioconversion, their amenability to hot water and dilute acid pretreatments and enzymatic hydrolysis was evaluated. Lignin reductions resulted in 1.9-3.2-fold increases in glucose release compared to the control. However, no apparent benefit was observed by S lignin incorporation at the concentrations reported in this study. Finally, these results highlight the potential for softwood cell wall properties to be improved for bioenergy/biochemical applications.« less

Bioconversion of fish solid waste into PHB using Bacillus subtilis based submerged fermentation process.

PubMed

Mohapatra, S; Sarkar, B; Samantaray, D P; Daware, A; Maity, S; Pattnaik, S; Bhattacharjee, S

2017-12-01

Currently, one of the major problem affecting the world is solid waste management, predominantly petroleum-based plastic and fish solid waste (FSW). However, it is very difficult to reduce the consumption of plastic as well as fish products, but it is promising to convert FSW to biopolymer to reduce eco-pollution. On account of that, the bioconversion of FSW extract to polyhydroxybutyrate (PHB) was undertaken by using Bacillus subtilis (KP172548). Under optimized conditions, 1.62 g/L of PHB has been produced by the bacterium. The purified compound was further characterized by advanced analytical technologies to elucidate its chemical structure. Results indicated that the biopolymer was found to be PHB, the most common homopolymer of polyhydroxyalkanoates (PHAs). This is the first report demonstrating the efficacy of B. subtilis to utilize FSW extract to produce biopolymer. The biocompatibility of the PHB against murine macrophage cell line RAW264.7 demonstrated that, it was comparatively less toxic, favourable for surface attachment and proliferation in comparison with poly-lactic acid (PLA) and commercially available PHB. Thus, further exploration is highly indispensable to use FSW extract as a substrate for production of PHB at pilot scale.

Elimination of sulphur odours at landfills by bioconversion and the corona discharge plasma technique.

PubMed

Xia, Fangfang; Liu, Xin; Kang, Ying; He, Ruo; Wu, Zucheng

2015-01-01

Hydrogen sulphide (H2S) contributes a lot to odours at landfills, which is a threat to the environment and the health of the staff therein. To mitigate its emission, the bioconversion within landfill cover soils (LCSs) was introduced. H2S emission and concentration both in the field air above the landfill and in microcosm testing were surveyed. Results indicated that H2S emission and concentration in the landfill varied with landfill seasons and sites. There existed relationship between H2S concentration and fluxes spatially and temporally. To characterize and assess the spatial and temporal diversity of sulphur-oxidizing bacteria (SOB) and sulphate-reducing bacteria (SRB) in the LCSs, the terminal-restriction fragment length polymorphism technique was employed. Using the functional genes of dsrB and soxB, SOB, including Halothiobacillus, Rhodothalassium, Paracocccus, Allochromatium, and Thiobacillus, and SRB, including Desulfovibrio, Syntrophobacter, Desulfomonile and Desulfobacca, were identical and exhibited the dominant role in the LCSs. By employing an alternative available corona reactor, more than 90% removal efficiencies of sulphides were demonstrated, suggesting that the LCSs for eliminating odours in a lower concentration would be feasible.

Characterization and enzymatic hydrolysis of wood from transgenic Pinus taeda engineered with syringyl lignin or reduced lignin content

DOE PAGES

Edmunds, Charles W.; Peralta, Perry; Kelley, Stephen S.; ...

2017-02-22

Softwood is an abundant resource; however, currently its utilization for bioconversion to obtain platform sugars is limited. Pinus taeda trees which were genetically modified to either produce S lignin or to decrease lignin content were characterized with a suite of analytic techniques. Syringyl lignin was visualized in the secondary xylem of one genetic line with Maule staining. Solid-state nuclear magnetic resonance identified the S lignin units were coupled into the lignin through β-O-4 linkages, and thioacidolysis measured approximately 13% S lignin content in the same sample. Reductions of the lignin of as much as 33% were observed in the transgenics.more » To better understand how these modifications affect bioconversion, their amenability to hot water and dilute acid pretreatments and enzymatic hydrolysis was evaluated. Lignin reductions resulted in 1.9-3.2-fold increases in glucose release compared to the control. However, no apparent benefit was observed by S lignin incorporation at the concentrations reported in this study. Finally, these results highlight the potential for softwood cell wall properties to be improved for bioenergy/biochemical applications.« less

Effect of irradiation, as a pretreatment, on bioconversion of corn stover into protein-rich mycelial biomass of Pleurotus sajor-caju

NASA Astrophysics Data System (ADS)

Awafo, V. A.; Chahal, D. S.; Charbonneau, R.

1995-09-01

Application of irradiation for food preservation, for pretreatment of lignocellulosic materials for their hydrolysis and to increase the digestibility of lignocellulosic materials for rumen animals have been reported in the literature. In the present study, irradiation (100 KGy to 1.7 MGy) of corn stover as a pretreatment to make it susceptible for its bioconversion into protein-rich mycelial biomass of Pleurotus sajor-caju NRRL 18757 has been compared with that of mild alkali treatment (0.01 to 0.15 g NaOH/g corn stover), the most commonly used pretreatment. Protein synthesis increased with the increase in doses of irradiation as well as with the increase in concentration of NaOH. Combination pretreatment with NaOH and γ-irradiation reduced the quantity of NaOH and doses of irradiation required to get optimum yields of protein indicating a strong synergistic effect. The highest protein content of the final product, mycelial biomass, was about 45% on dry weight basis. More than 90% utilization of corn stover polysaccharides for the synthesis of protein-rich mycelial biomass of P. sajor-caju was recorded

Bioconversion of Lignocellulosic Biomass to Fermentable Sugars by Immobilized Magnetic Cellulolytic Enzyme Cocktails.

PubMed

Periyasamy, Karthik; Santhalembi, Laishram; Mortha, Gérard; Aurousseau, Marc; Boyer, Agnès; Subramanian, Sivanesan

2018-06-05

Enzyme cocktails of reusable, highly stable cellulolytic enzymes play an inevitable role in bioconversion of biomass to biofuels economically. Cellulase, xylanase and β-1,3-glucanase bound silica-amine functionalized iron oxide magnetic nanoparticles (ISN-CLEAs) were prepared and used as the biocatalyst for the depolymerization of cellulosic biomass into monomeric sugar in the present study. The Fe 3 O 4 -NPs and Fe 3 O 4 @SiO 2 -NH 2 -NPs and ISN-CLEAs had an average hydrodynamic size of 82.2, 86.4, and 976.9 nm, respectively, which was confirmed by dynamic light scattering (DLS). About 97% of protein binding was achieved with 135 mM glutaraldehyde at 10 h of cross-linking time and successful binding was confirmed by Fourier transform infrared spectroscopy (FTIR). The ISN-CLEAs exhibited the highest thermal stability of 95% at 50 °C for 2 h and retained extended storage stability of 97% compared to 60% of its free counterpart. Besides, cross-linking allowed ISN-CLEAs reuse for at least eight consecutive cycles retaining over 70% of its initial activity. ISN-CLEAs exhibited approximately 15% increase in carbohydrate digestibility on sugar cane bagasse and eucalyptus pulp than the free enzyme.

Effect of cell-surface hydrophobicity on bacterial conversion of water-immiscible chemicals in two-liquid-phase culture systems.

PubMed

Hamada, Takahiro; Maeda, Yusuke; Matsuda, Hiroyuki; Sameshima, Yuka; Honda, Kohsuke; Omasa, Takeshi; Kato, Junichi; Ohtake, Hisao

2009-08-01

The effect of bacterial cell-surface hydrophobicity on the bioconversion of water-immiscible chemicals in an aqueous-organic (A/O) two-liquid-phase culture system was investigated. Escherichia coli JM109 and Rhodococcus opacus B-4 were used as hydrophilic and hydrophobic whole-cell catalysts, respectively. Hydroxylation reactions of monoaromatics, including toluene (log P(ow)=2.9), ethylbenzene (3.1), n-propylbenzene (3.4), and sec-butylbenzene (3.7), were employed as model conversions. When the todC1C2BA genes encoding Pseudomonas putida toluene dioxygenase were expressed in E. coli JM109, the yield of hydroxylated monoaromatics decreased with increasing substrate hydrophobicity. By contrast, R. opacus transformants, which expressed the todC1C2BA genes, showed high performance in the hydroxylation of monoaromatics, irrespective of substrate hydrophobicity. When the R. opacus transformants were examined for their ability to hydroxylate monoaromatics in an aqueous single-liquid-phase culture, the reaction velocity was markedly lower than that observed in the A/O two-liquid-phase culture. These results suggested that R. opacus B-4 accessed the hydrophobic substrates in the oil phase, thus making it more effective for the bioconversion reactions.

Production of chemicals from C1 gases (CO, CO2) by Clostridium carboxidivorans.

PubMed

Fernández-Naveira, Ánxela; Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2017-03-01

Bioprocesses in conventional second generation biorefineries are mainly based on the fermentation of sugars obtained from lignocellulosic biomass or agro-industrial wastes. An alternative to this process consists in gasifying those same feedstocks or even other carbon-containing materials to obtain syngas which can also be fermented by some anaerobic bacteria to produce chemicals or fuels. Carbon monoxide, carbon dioxide and hydrogen, which are the main components of syngas, are also found in some industrial waste gases, among others in steel industries. Clostridium carboxidivorans is able to metabolise such gases to produce ethanol and higher alcohols, i.e. butanol and hexanol, following the Wood-Ljungdahl pathway. This does simultaneously allow the removal of volatile pollutants involved in climate change. The bioconversion is a two step process in which organic acids (acetate, butyrate, hexanoate) are produced first, followed by the accumulation of alcohols; although partial overlap in time of acids and alcohols production may sometimes take place as well. Several parameters, among others pH, temperature, or gas-feed flow rates in bioreactors, affect the bioconversion process. Besides, the accumulation of high concentrations of alcohols in the fermentation broth inhibits the growth and metabolic activity of C. carboxidivorans.

Novel Magnetic Cross-Linked Cellulase Aggregates with a Potential Application in Lignocellulosic Biomass Bioconversion.

PubMed

Jia, Junqi; Zhang, Weiwei; Yang, Zengjie; Yang, Xianling; Wang, Na; Yu, Xiaoqi

2017-02-10

The utilization of renewable biomass resources to produce high-value chemicals by enzymatic processes is beneficial for alternative energy production, due to the accelerating depletion of fossil fuels. As immobilization techniques can improve enzyme stability and reusability, a novel magnetic cross-linked cellulase aggregate has been developed and applied for biomass bioconversion. The crosslinked aggregates could purify and immobilize enzymes in a single operation, and could then be combined with magnetic nanoparticles (MNPs), which provides easy separation of the materials. The immobilized cellulase showed a better activity at a wider temperature range and pH values than that of the free cellulase. After six cycles of consecutive reuse, the immobilized cellulase performed successful magnetic separation and retained 74% of its initial activity when carboxylmethyl cellulose (CMC) was used as the model substrate. Furthermore, the structure and morphology of the immobilized cellulase were studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Moreover, the immobilized cellulase was shown to hydrolyze bamboo biomass with a yield of 21%, and was re-used in biomass conversion up to four cycles with 38% activity retention, which indicated that the immobilized enzyme has good potential for biomass applications.

Bioconversion of petroleum hydrocarbons in soil using apple filter cake

PubMed Central

Medaura, M. Cecilia; Ércoli, Eduardo C.

2008-01-01

The aim of this study was to investigate the feasibility of using apple filter cake, a fruit-processing waste to enhance the bioremediation of petroleum contaminated soil. A rotating barrel system was used to study the bioconversion of the xenobiotic compound by natural occurring microbial population. The soil had been accidentally polluted with a total petroleum hydrocarbon concentration of 41,000 ppm. Although this global value was maintained during the process, microbial intervention was evidenced through transformation of the petroleum fractions. Thus, fractions that represent a risk for the environment (GRO, Gasoline Range Organics i.e., C6 to C10–12; DRO, Diesel Range Organics i.e., C8–12 to C24–26 and RRO, Residual Range Organics i.e., C25 to C35) were significantly reduced, from 2.95% to 1.39%. On the contrary, heavier weight fraction from C35 plus other organics increased in value from 1.15% to 3.00%. The noticeable diminution of low molecular weight hydrocarbons content and hence environmental risk by the process plus the improvement of the physical characteristics of the soil, are promising results with regard to future application at large scale. PMID:24031241

Bioconversion of beetle-killed lodgepole pine using SPORL: Process scale-up design, lignin co-product, and high solids fermentation without detoxification

USDA-ARS?s Scientific Manuscript database

Mountain pine beetle killed Lodgepole pine (Pinus contorta Douglas ex Loudon) wood chips were pretreated using an acidic sulfite solution of approximately pH = 2.0 at a liquor to wood ratio of 3 and sodium bisulfite loading of 8 wt % on wood. The combined hydrolysis factor (CHF), formulated from rea...

Structural insight into catalytic mechanism of PET hydrolase.

PubMed

Han, Xu; Liu, Weidong; Huang, Jian-Wen; Ma, Jiantao; Zheng, Yingying; Ko, Tzu-Ping; Xu, Limin; Cheng, Ya-Shan; Chen, Chun-Chi; Guo, Rey-Ting

2017-12-13

PET hydrolase (PETase), which hydrolyzes polyethylene terephthalate (PET) into soluble building blocks, provides an attractive avenue for the bioconversion of plastics. Here we present the structures of a novel PETase from the PET-consuming microbe Ideonella sakaiensis in complex with substrate and product analogs. Through structural analyses, mutagenesis, and activity measurements, a substrate-binding mode is proposed, and several features critical for catalysis are elucidated.

Engineering a Synthetic Microbial Consortium for Comprehensive Conversion of Algae Biomass into Terpenes for Advanced Biofuels and Bioproducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Weihua; Wu, Benjamin Chiau-Pin; Davis, Ryan Wesley

Recent strategies for algae-based biofuels have primarily focused on biodiesel production by exploiting high algal lipid yields under nutrient stress conditions. However, under conditions supporting robust algal biomass accumulation, carbohydrate and proteins typically comprise up to ~80% of the ash-free dry weight of algae biomass. Therefore, comprehensive utilization of algal biomass for production of multipurpose intermediate- to high-value bio-based products will promote scale-up of algae production and processing to commodity volumes. Terpenes are hydrocarbon and hydrocarbon-like (C:O>10:1) compounds with high energy density, and are therefore potentially promising candidates for the next generation of value added bio-based chemicals and “drop-in” replacementsmore » for petroleum-based fuels. In this study, we demonstrated the feasibility of bioconversion of proteins into sesquiterpene compounds as well as comprehensive bioconversion of algal carbohydrates and proteins into biofuels. To achieve this, the mevalonate pathway was reconstructed into an E. coli chassis with six different terpene synthases (TSs). Strains containing the various TSs produced a spectrum of sesquiterpene compounds in minimal medium containing amino acids as the sole carbon source. The sesquiterpene production was optimized through three different regulation strategies using chamigrene synthase as an example. The highest total terpene titer reached 166 mg/L, and was achieved by applying a strategy to minimize mevalonate accumulation in vivo. The highest yields of total terpene were produced under reduced IPTG induction levels (0.25 mM), reduced induction temperature (25°C), and elevated substrate concentration (20 g/L amino acid mixture). A synthetic bioconversion consortium consisting of two engineering E. coli strains (DH1-TS and YH40-TS) with reconstructed terpene biosynthetic pathways was designed for comprehensive single-pot conversion of algal carbohydrates and proteins to sesquiterpenes. The consortium yielded the highest total terpene yields (187 mg/L) at an inoculum ratio 2:1 of strain YH40-TS: DH1-TS, corresponding to 31 mg fuel/g algae biomass ash free dry weight. This study therefore demonstrates a feasible process for comprehensive algal biofuel production.« less

Responsive polymer-based colloids for drug delivery and bioconversion

NASA Astrophysics Data System (ADS)

Kudina, Olena

Responsive polymer-based colloids (RPBC) are the colloidal structures containing responsive polymeric component which is able to adapt its physico-chemical properties to the environment by undergoing chemical and/or conformational changes. The goal of the dissertation is to develop and characterize several groups of RPBC with different morphological complexity and explore their potential in drug delivery and bioconversion. The role of RPBC morphology for these specific applications is discussed in details. Three groups of RPBC were fabricated: i. polymeric micelles; ii. mixed polymeric micelles; iii. hybrid polymer-inorganic particles. All fabricated RPBCs contain polymeric component in their structure. The dissertation investigates how the changes of the responsive polymeric component properties are reflected in morphologies of RPBC. The first group of RPBC, polymeric micelles, was formed by the self-assembly of amphiphilic invertible polymers (AIPs) synthesized in our group. AIPs self-assemble into invertible micellar assemblies (IMAs) in solvents of different polarity. In this work, IMAs ability to invert the structure as a response to the change in solvent polarity was demonstrated using 1H NMR spectroscopy and SANS. It was shown that the IMAs incorporate hydrophobic cargo either in the core or in the shell, depending on the chemical structure of cargo molecules. Following in vitro study demonstrates that loaded with drug (curcumin) IMAs are cytotoxic to osteosarcoma cells. Mixed polymeric micelles represent another, more complex, RPBC morphologies studied in the dissertation. Mixed micelles were fabricated from AIPs and amphiphilic oligomers synthesized from pyromellitic dianhydride, polyethylene glycol methyl ethers, and alkanols/cholesterol. The combination of selected AIP and oligomers based on cholesterol results in mixed micelles with an increased drug-loading capacity (from 10% w/w loaded curcumin in single component IMAs to 26%w/w in mixed micelles). Even more complex colloids are hybrid polymer-inorganic particles, the third RPBC group studied in dissertation. Material was designed as core--shell particles with superparamagnetic core engulfed by grafted polymer brushes. These particles were loaded with enzymes (cellulases), thus, are turned into enzymogels for cellulose bioconversion. The study demonstrates that such RPBCs can be used multiple times during hydrolysis and provide an about four-fold increase in glucose production in comparison to free enzymes.

Bioconversion of biodiesel-derived crude glycerol into lipids and carotenoids by an oleaginous red yeast Sporidiobolus pararoseus KM281507 in an airlift bioreactor.

PubMed

Manowattana, Atchara; Techapun, Charin; Watanabe, Masanori; Chaiyaso, Thanongsak

2018-01-01

Here we tested the bioconversion of biodiesel-derived crude glycerol by the oleaginous red yeast Sporidiobolus pararoseus KM281507 in two bioreactors types (stirred-tank and airlift). High production yields (biomass, 10.62 ± 0.21 g/L; lipids, 3.26 ± 0.13 g/L; β-carotene, 30.64 ± 0.05 mg/L; total carotenoids, 46.59 ± 0.07 mg/L) were achieved in a 3.0 L airlift bioreactor under uncontrolled pH regimes (initial pH 5.63). Under optimized conditions (6.0 vvm aeration rate; 60 ± 5% constant dissolved oxygen [DO] maintained by flushing pure oxygen [O 2 ] into the vessel; 10,000 Lux light irradiation) volumetric production in the airlift bioreactor was further increased (biomass, 19.30 ± 1.07 g/L; lipids, 6.61 ± 0.04 g/L, β-carotene, 109.75 ± 0.21 mg/L; total carotenoids 151.00 ± 2.71 mg/L). Production was also recorded at a S. pararoseus KM281507 growth rate of 0.16 ± 0.00 h -1 (lipids, 0.94 ± 0.04 g/L/d; β-carotene, 15.68 ± 0.40 mg/L/d; total carotenoids, 21.56 ± 0.20 mg/L/d). Lipids from S. pararoseus KM281507 had a high unsaturated fatty acid content, with oleic acid (C18:1) accounting for 80% of all fatty acids. This high oleic acid content makes S. pararoseus KM281507 well-suited as a third generation biodiesel feedstock. Our findings show that airlift bioreactors are suitable for bioconversion of crude glycerol into lipids and carotenoids using S. pararoseus KM281507. This approach is advantageous because of its ease of operation, cost efficiency, and low energy consumption. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

High-level expression of thermostable cellulolytic enzymes in tobacco transplastomic plants and their use in hydrolysis of an industrially pretreated Arundo donax L. biomass.

PubMed

Castiglia, Daniela; Sannino, Lorenza; Marcolongo, Loredana; Ionata, Elena; Tamburino, Rachele; De Stradis, Angelo; Cobucci-Ponzano, Beatrice; Moracci, Marco; La Cara, Francesco; Scotti, Nunzia

2016-01-01

Biofuels production from plant biomasses is a complex multi-step process with important economic burdens. Several biotechnological approaches have been pursued to reduce biofuels production costs. The aim of the present study was to explore the production in tobacco plastome of three genes encoding (hemi)cellulolytic enzymes from thermophilic and hyperthermophilic bacterium and Archaea, respectively, and test their application in the bioconversion of an important industrially pretreated biomass feedstock (A. donax) for production of second-generation biofuels. The selected enzymes, endoglucanase, endo-β-1,4-xylanase and β-glucosidase, were expressed in tobacco plastome with a protein yield range from 2 % to more than 75 % of total soluble proteins (TSP). The accumulation of endoglucanase (up to 2 % TSP) gave altered plant phenotypes whose severity was directly linked to the enzyme yield. The most severe seedling-lethal phenotype was due to the impairment of plastid development associated to the binding of endoglucanase protein to thylakoids. Endo-β-1,4-xylanase and β-glucosidase, produced at very high level without detrimental effects on plant development, were enriched (fourfold) by heat treatment (105.4 and 255.4 U/mg, respectively). Both plastid-derived biocatalysts retained the main features of the native or recombinantly expressed enzymes with interesting differences. Plastid-derived xylanase and β-glucosidase resulted more thermophilic than the E. coli recombinant and native counterpart, respectively. Bioconversion experiments, carried out at 50 and 60 °C, demonstrated that plastid-derived enzymes were able to hydrolyse an industrially pretreated giant reed biomass. In particular, the replacement of commercial enzyme with plastid-derived xylanase, at 60 °C, produced an increase of both xylose recovery and hydrolysis rate; whereas the replacement of both xylanase and β-glucosidase produced glucose levels similar to those observed with the commercial cocktails, and xylose yields always higher in the whole 24-72 h range. The very high production level of thermophilic and hyperthermophilic enzymes, their stability and bioconversion efficiencies described in this study demonstrate that plastid transformation represents a real cost-effective production platform for cellulolytic enzymes.

Pretreatment of corn stover by low moisture anhydrous ammonia (LMMA) in a pilot-scale reactor and bioconversion to fuel ethanol and industrial chemicals

USDA-ARS?s Scientific Manuscript database

Corn stover (CS) adjusted to 50%, 66% and 70% moisture was pretreated by the low moisture anhydrous ammonia (LMAA) process in a pilot-scale ammoniation reactor. After ammoniation, the 70% moisture CS was treated at 90 degree C and 100 degree C whereas the others were treated at 90 degree C only. The...

Using sulfite chemistry for robust bioconversion of Douglas-fir forest residue to bioethanol at high titer and lignosulfonate: A pilot-scale evaluation

Treesearch

J.Y. Zhu; M. Subhosh Chandra; Feng Gu; Roland Gleisner; J.Y. Zhu; John Sessions; Gevan Marrs; Johnway Gao; Dwight Anderson

2015-01-01

This study demonstrated at the pilot-scale (50 kg) use of Douglas-fir forest harvest residue, an underutilized forest biomass, for the production of high titer and high yield bioethanol using sulfite chemistry without solid–liquor separation and detoxification. Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses (SPORL) was directly applied to the...

Bioconversion of Beetle-Killed Lodgepole Pine Using SPORL: Process Scale-up Design, Lignin Coproduct, and High Solids Fermentation without detoxification

Treesearch

Haifeng Zhou; J.Y. Zhu; Xiaolin Luo; Shao-Yuan Leu; Xiaolei Wu; Roland Gleisner; Bruce S. Dien; Ronald E. Hector; Dongjie Yang; Xueqing Qiu; Eric Horn; Jose Negron

2013-01-01

Mountain pine beetle killed Lodgepole pine (Pinus contorta Douglas ex Loudon) wood chips were pretreated using an acidic sulfite solution of approximately pH = 2.0 at a liquor to wood ratio of 3 and sodium bisulfite loading of 8 wt % on wood. The combined hydrolysis factor (CHF), formulated from reaction kinetics, was used to design a scale-up...

Changes in pore structure of coal caused by coal-to-gas bioconversion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Rui; Liu, Shimin; Bahadur, Jitendra

Microbial enhanced coalbed methane (ME-CBM) recovery is critically examined as a viable technology for natural gas recovery from coalbed methane (CBM) reservoirs. Since the majority of gas-in-place (GIP) is stored as an adsorbed phase in fine pores of coal matrix, the nano-pore structure directly influences gas storage and transport properties. Only limited studies have quantified the alteration of the nano-pore structure due to ME-CBM treatment. This study examines the evolution of the pore structure using a combination of small angle X-ray scattering (SAXS), low-pressure N 2 and CO 2 adsorption (LPGA) and high-pressure methane adsorption methods. The results show thatmore » the surface fractal dimension decreases for the two bioconverted coals compared to the untreated coal. After bio-treatment, the mesopore surface area and pore volume decrease with the average pore diameter increases, while the micropore surface area increases with pore volume decreases. Both inaccessible meso-/micropore size distributions decrease after bioconversion, while the accessible micropore size distribution increases, making a portion of closed micropore network accessible. In addition, the methane adsorption capacities increase after bio-treatment, which is confirmed by the increase of micropore surface area. A conceptual physical model of methanogenesis is proposed based on the evolution of the pore structure.« less

Changes in pore structure of coal caused by coal-to-gas bioconversion

DOE PAGES

Zhang, Rui; Liu, Shimin; Bahadur, Jitendra; ...

2017-06-19

Microbial enhanced coalbed methane (ME-CBM) recovery is critically examined as a viable technology for natural gas recovery from coalbed methane (CBM) reservoirs. Since the majority of gas-in-place (GIP) is stored as an adsorbed phase in fine pores of coal matrix, the nano-pore structure directly influences gas storage and transport properties. Only limited studies have quantified the alteration of the nano-pore structure due to ME-CBM treatment. This study examines the evolution of the pore structure using a combination of small angle X-ray scattering (SAXS), low-pressure N 2 and CO 2 adsorption (LPGA) and high-pressure methane adsorption methods. The results show thatmore » the surface fractal dimension decreases for the two bioconverted coals compared to the untreated coal. After bio-treatment, the mesopore surface area and pore volume decrease with the average pore diameter increases, while the micropore surface area increases with pore volume decreases. Both inaccessible meso-/micropore size distributions decrease after bioconversion, while the accessible micropore size distribution increases, making a portion of closed micropore network accessible. In addition, the methane adsorption capacities increase after bio-treatment, which is confirmed by the increase of micropore surface area. A conceptual physical model of methanogenesis is proposed based on the evolution of the pore structure.« less

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung-waste paper mixtures.

PubMed

Unuofin, F O; Mnkeni, P N S

2014-11-01

Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung-paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg(-1) dry weight of cow dung-waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg(-1) resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg(-1) feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered. Copyright © 2014. Published by Elsevier Ltd.

A metabolic pathway for catabolizing levulinic acid in bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rand, Jacqueline M.; Pisithkul, Tippapha; Clark, Ryan L.

Microorganisms can catabolize a wide range of organic compounds and therefore have the potential to perform many industrially relevant bioconversions. One barrier to realizing the potential of biorefining strategies lies in our incomplete knowledge of metabolic pathways, including those that can be used to assimilate naturally abundant or easily generated feedstocks. For instance, levulinic acid (LA) is a carbon source that is readily obtainable as a dehydration product of lignocellulosic biomass and can serve as the sole carbon source for some bacteria. Yet, the genetics and structure of LA catabolism have remained unknown. Here, we report the identification and characterizationmore » of a seven-gene operon that enables LA catabolism in Pseudomonas putida KT2440. When the pathway was reconstituted with purified proteins, we observed the formation of four acyl-CoA intermediates, including a unique 4-phosphovaleryl-CoA and the previously observed 3-hydroxyvaleryl-CoA product. Using adaptive evolution, we obtained a mutant of Escherichia coli LS5218 with functional deletions of fadE and atoC that was capable of robust growth on LA when it expressed the five enzymes from the P. putida operon. Here, this discovery will enable more efficient use of biomass hydrolysates and metabolic engineering to develop bioconversions using LA as a feedstock.« less

A metabolic pathway for catabolizing levulinic acid in bacteria

DOE PAGES

Rand, Jacqueline M.; Pisithkul, Tippapha; Clark, Ryan L.; ...

2017-09-25

Microorganisms can catabolize a wide range of organic compounds and therefore have the potential to perform many industrially relevant bioconversions. One barrier to realizing the potential of biorefining strategies lies in our incomplete knowledge of metabolic pathways, including those that can be used to assimilate naturally abundant or easily generated feedstocks. For instance, levulinic acid (LA) is a carbon source that is readily obtainable as a dehydration product of lignocellulosic biomass and can serve as the sole carbon source for some bacteria. Yet, the genetics and structure of LA catabolism have remained unknown. Here, we report the identification and characterizationmore » of a seven-gene operon that enables LA catabolism in Pseudomonas putida KT2440. When the pathway was reconstituted with purified proteins, we observed the formation of four acyl-CoA intermediates, including a unique 4-phosphovaleryl-CoA and the previously observed 3-hydroxyvaleryl-CoA product. Using adaptive evolution, we obtained a mutant of Escherichia coli LS5218 with functional deletions of fadE and atoC that was capable of robust growth on LA when it expressed the five enzymes from the P. putida operon. Here, this discovery will enable more efficient use of biomass hydrolysates and metabolic engineering to develop bioconversions using LA as a feedstock.« less

Quantitative investigation of non-hydrolytic disruptive activity on crystalline cellulose and application to recombinant swollenin.

PubMed

Wang, Yuguo; Tang, Rentao; Tao, Jin; Gao, Gui; Wang, Xiaonan; Mu, Ying; Feng, Yan

2011-09-01

For the efficient degradation and bioconversion of cellulosic biomass, it is important to efficiently disrupt and convert crystalline regions of cellulose into easily hydrolyzable regions than to simply hydrolyze cellulose. Expansin-like proteins such as swollenins have disruptive functions on lignocellulose, including crystalline cellulose, via non-hydrolytic mechanisms. In this work, we produced the swollenin from Trichoderma asperellum in Escherichia coli. The recombinant protein was then refolded into the bioactive form with simultaneous purification via a novel cellulose-assisted process. We devised a novel, simple, and efficient method to quantitatively determine the non-hydrolytic disruptive activity of swollenin on crystalline cellulose. This method is based on the synergism of the swollenin and the endoglucanase FnCel5A from Fervidobacterium nodosum. The change from crystalline regions into easily hydrolyzable forms, due to non-hydrolytic disruption, might be slight and not easily be observed. However, disrupted regions of cellulose could be hydrolyzed by FnCel5A, and reducing sugars were formed by the synergism. The disruptive function of the swollenin was quantitatively characterized by measuring the release of reducing sugars. These methods and processes will be useful for further research on non-hydrolytic disruptive bioactivities and provide novel approaches for the efficient and economical bioconversion of cellulosic biomass.

Bioconversion of 6-(N-methyl-N-phenyl)aminomethyl androstane steroids by Nocardioides simplex.

PubMed

Sukhodolskaya, Galina; Fokina, Victoria; Shutov, Andrei; Nikolayeva, Vera; Savinova, Tatiana; Grishin, Yuri; Kazantsev, Alexey; Lukashev, Nikolay; Donova, Marina

2017-02-01

The newly synthesized (α/β)-diastereomers of 6-(N-methyl-N-phenyl)aminomethylandrost-4-ene-3,17-dione (5) and 6-(N-methyl-N-phenyl)aminomethylandrost-4-en-17β-ol-3-one (6) were firstly investigated as substrates for the whole cells of Nocardioides simplex VKM Ac-2033D in comparison with their unsubstituted analogs, - androst-4-ene-3,17-dione (1) and androst-4-en-17β-ol-3-one (2). 1(2)-Dehydroderivatives were identified as the major bioconversion products from all the substrates tested. When using the mixtures of (α/β)-stereoisomers of 5 and 6 as the substrates, only β-stereoisomers of the corresponding 1,4-diene-steroids were formed. Along with 1(2)-dehydrogenation, N. simplex VKM Ac-2033D promoted oxidation of the hydroxyl group at C-17 position of 6: both 6(α) and 6(β) were transformed to the corresponding 17-keto derivatives. No steroid core destruction was observed during the conversion of the 6-substituted androstanes 5 and 6, while it was significant when 1 or 2 was used as the substrate. The results suggested high potentials of N. simplex VKM Ac-2033D for the generation of novel 1(2)-dehydroanalogs. Copyright © 2016 Elsevier Inc. All rights reserved.

The modeling of ethanol production by Kluyveromyces marxianus using whey as substrate in continuous A-Stat bioreactors.

PubMed

Gabardo, Sabrina; Pereira, Gabriela Feix; Rech, Rosane; Ayub, Marco Antônio Záchia

2015-09-01

We investigated the kinetics of whey bioconversion into ethanol by Kluyveromyces marxianus in continuous bioreactors using the "accelerostat technique" (A-stat). Cultivations using free and Ca-alginate immobilized cells were evaluated using two different acceleration rates (a). The kinetic profiles of these systems were modeled using four different unstructured models, differing in the expressions for the specific growth (μ) and substrate consumption rates (r s), taking into account substrate limitation and product inhibition. Experimental data showed that the dilution rate (D) directly affected cell physiology and metabolism. The specific growth rate followed the dilution rate (μ≈D) for the lowest acceleration rate (a = 0.0015 h(-2)), condition in which the highest ethanol yield (0.52 g g(-1)) was obtained. The highest acceleration rate (a = 0.00667 h(-2)) led to a lower ethanol yield (0.40 g g(-1)) in the system where free cells were used, whereas with immobilized cells ethanol yields increased by 23 % (0.49 g g(-1)). Among the evaluated models, Monod and Levenspiel combined with Ghose and Tyagi models were found to be more appropriate for describing the kinetics of whey bioconversion into ethanol. These results may be useful in scaling up the process for ethanol production from whey.

Screening tests for assessing the anaerobic biodegradation of pollutant chemicals in subsurface environments

USGS Publications Warehouse

Suflita, Joseph M.; Concannon, Frank

1995-01-01

Screening methods were developed to assess the susceptibility of ground water contaminants to anaerobic biodegradation. One method was an extrapolation of a procedure previously used to measure biodegradation activity in dilute sewage sludge. Aquifer solids and ground water with no additional nutritive media were incubated anaerobically in 160-ml serum bottles containing 250 mg·l−1 carbon of the substrate of interest. This method relied on the detection of gas pressure or methane production in substrateamended microcosms relative to background controls. Other screening procedures involved the consumption of stoichiometrically required amounts of sulfate or nitrate from the same type of incubations. Close agreement was obtained between the measured and calculated amounts of substrate bioconversion based on the measured biogas pressure in methanogenic microcosms. Storage of the microcosms for up to 6 months did not adversely influence the onset or rate of benzoic acid mineralization. The lower detection limits of the methanogenic assay were found to be a function of the size of the microcosm headspace, the mean oxidation state of the substrate carbon, and the method used to correct for background temperature fluctuations. Using these simple screening procedures, biodegradation information of regulatory interest could be generated, including, (i) the length of the adaptation period, (ii) the rate of substrate decay and (iii) the completeness of the bioconversion.

Enzymatic saccharification and fermentation of cellulosic date palm wastes to glucose and lactic acid.

PubMed

Alrumman, Sulaiman A

2016-01-01

The bioconversion of cellulosic wastes into high-value bio-products by saccharification and fermentation processes is an important step that can reduce the environmental pollution caused by agricultural wastes. In this study, enzymatic saccharification of treated and untreated date palm cellulosic wastes by the cellulases from Geobacillus stearothermophilus was optimized. The alkaline pre-treatment of the date palm wastes was found to be effective in increasing the saccharification percentage. The maximum rate of saccharification was found at a substrate concentration of 4% and enzyme concentration of 30 FPU/g of substrate. The optimum pH and temperature for the bioconversions were 5.0 and 50°C, respectively, after 24h of incubation, with a yield of 31.56mg/mL of glucose at a saccharification degree of 71.03%. The saccharification was increased to 94.88% by removal of the hydrolysate after 24h by using a two-step hydrolysis. Significant lactic acid production (27.8mg/mL) was obtained by separate saccharification and fermentation after 72h of incubation. The results indicate that production of fermentable sugar and lactic acid is feasible and may reduce environmental pollution by using date palm wastes as a cheap substrate. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Highly Selective Bioconversion of Ginsenoside Rb1 to Compound K by the Mycelium of Cordyceps sinensis under Optimized Conditions.

PubMed

Wang, Wei-Nan; Yan, Bing-Xiong; Xu, Wen-Di; Qiu, Ye; Guo, Yun-Long; Qiu, Zhi-Dong

2015-10-23

Compound K (CK), a highly active and bioavailable derivative obtained from protopanaxadiol ginsenosides, displays a wide variety of pharmacological properties, especially antitumor activity. However, the inadequacy of natural sources limits its application in the pharmaceutical industry. In this study, we firstly discovered that Cordyceps sinensis was a potent biocatalyst for the biotransformation of ginsenoside Rb1 into CK. After a series of investigations on the biotransformation parameters, an optimal composition of the biotransformation culture was found to be lactose, soybean powder and MgSO₄ without controlling the pH. Also, an optimum temperature of 30 °C for the biotransformation process was suggested in a range of 25 °C-50 °C. Then, a biotransformation pathway of Rb1→Rd→F2→CK was established using high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF-MS). Our results demonstrated that the molar bioconversion rate of Rb1 to CK was more than 82% and the purity of CK produced by C. sinensis under the optimized conditions was more than 91%. In conclusion, the combination of C. sinensis and the optimized conditions is applicable for the industrial preparation of CK for medicinal purposes.

Enzymatic saccharification and fermentation of cellulosic date palm wastes to glucose and lactic acid

PubMed Central

Alrumman, Sulaiman A.

2016-01-01

The bioconversion of cellulosic wastes into high-value bio-products by saccharification and fermentation processes is an important step that can reduce the environmental pollution caused by agricultural wastes. In this study, enzymatic saccharification of treated and untreated date palm cellulosic wastes by the cellulases from Geobacillus stearothermophilus was optimized. The alkaline pre-treatment of the date palm wastes was found to be effective in increasing the saccharification percentage. The maximum rate of saccharification was found at a substrate concentration of 4% and enzyme concentration of 30 FPU/g of substrate. The optimum pH and temperature for the bioconversions were 5.0 and 50 °C, respectively, after 24 h of incubation, with a yield of 31.56 mg/mL of glucose at a saccharification degree of 71.03%. The saccharification was increased to 94.88% by removal of the hydrolysate after 24 h by using a two-step hydrolysis. Significant lactic acid production (27.8 mg/mL) was obtained by separate saccharification and fermentation after 72 h of incubation. The results indicate that production of fermentable sugar and lactic acid is feasible and may reduce environmental pollution by using date palm wastes as a cheap substrate. PMID:26887233

Anaerobic digestion as a waste disposal option for American Samoa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rivard, C

1993-01-01

Tuna sludge and municipal solid waste (MSW) generated on Tutuila Island, American Samoa, represent an ongoing disposal problem as well as an emerging opportunity for use in renewable fuel production. This research project focuses on the biological conversion of the organic fraction of these wastes to useful products including methane and fertilizer-grade residue through anaerobic high solids digestion. In this preliminary study, the anaerobic bioconversion of tuna sludge with MSW appears promising.

Engineering Ligninolytic Consortium for Bioconversion of Lignocelluloses to Ethanol and Chemicals.

PubMed

Bilal, Muhammad; Nawaz, Muhammad Zohaib; Iqbal, Hafiz M N; Hou, Jialin; Mahboob, Shahid; Al-Ghanim, Khalid A; Cheng, Hairong

2018-01-01

Rising environmental concerns and recent global scenario of cleaner production and consumption are leading to the design of green industrial processes to produce alternative fuels and chemicals. Although bioethanol is one of the most promising and eco-friendly alternatives to fossil fuels yet its production from food and feed has received much negative criticism. The main objective of this study was to present the noteworthy potentialities of lignocellulosic biomass as an enormous and renewable biological resource. The particular focus was also given on engineering ligninolytic consortium for bioconversion of lignocelluloses to ethanol and chemicals on sustainable and environmentally basis. Herein, an effort has been made to extensively review, analyze and compile salient information related to the topic of interest. Several authentic bibliographic databases including PubMed, Scopus, Elsevier, Springer, Bentham Science and other scientific databases were searched with utmost care, and inclusion/ exclusion criterion was adopted to appraise the quality of retrieved peer-reviewed research literature. Bioethanol production from lignocellulosic biomass can largely satisfy the possible inconsistency of first-generation ethanol since it utilizes inedible lignocellulosic feedstocks, primarily sourced from agriculture and forestry wastes. Two major polysaccharides in lignocellulosic biomass namely, cellulose and hemicellulose constitute a complex lignocellulosic network by connecting with lignin, which is highly recalcitrant to depolymerization. Several attempts have been made to reduce the cost involved in the process through improving the pretreatment process. While, the ligninolytic enzymes of white rot fungi (WRF) including laccase, lignin peroxidase (LiP), and manganese peroxidase (MnP) have appeared as versatile biocatalysts for delignification of several lignocellulosic residues. The first part of the review is mainly focused on engineering ligninolytic consortium. In the second part, WRF and its unique ligninolytic enzyme-based bio-delignification of lignocellulosic biomass, enzymatic hydrolysis, and fermentation of hydrolyzed feedstock are discussed. The metabolic engineering, enzymatic engineering, synthetic biology aspects for ethanol production and platform chemicals production are comprehensively reviewed in the third part. Towards the end information is also given on futuristic viewpoints. In conclusion, given the present unpredicted scenario of energy and fuel crisis accompanied by global warming, lignocellulosic bioethanol holds great promise as an alternative to petroleum. Apart from bioethanol, the simultaneous production of other value-added products may improve the economics of lignocellulosic bioethanol bioconversion process. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Soymilk residue (okara) as a natural immobilization carrier for Lactobacillus plantarum cells enhances soymilk fermentation, glucosidic isoflavone bioconversion, and cell survival under simulated gastric and intestinal conditions

PubMed Central

Xiudong, Xia; Ying, Wang; Xiaoli, Liu; Ying, Li

2016-01-01

Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. However, artificial immobilization carriers are expensive and pose a high safety risk. Okara, a food-grade byproduct from soymilk production, is rich in prebiotics. Lactobacilli could provide health enhancing effects to the host. This study aimed to evaluate the potential of okara as a natural immobilizer for L. plantarum 70810 cells. The study also aimed to evaluate the effects of okara-immobilized L. plantarum 70810 cells (IL) on soymilk fermentation, glucosidic isoflavone bioconversion, and cell resistance to simulated gastric and intestinal stresses. Scanning electron microscopy (SEM) was used to show cells adherence to the surface of okara. Lactic acid, acetic acid and isoflavone analyses in unfermented and fermented soymilk were performed by HPLC with UV detection. Viability and growth kinetics of immobilized and free L. plantarum 70810 cells (FL) were followed during soymilk fermentation. Moreover, changes in pH, titrable acidity and viscosity were measured by conventional methods. For in vitro testing of simulated gastrointestinal resistance, fermented soymilk was inoculated with FL or IL and an aliquot incubated into acidic MRS broth which was conveniently prepared to simulate gastric, pancreatic juices and bile salts. Survival to simulated gastric and intestinal stresses was evaluated by plate count of colony forming units on MRS agar. SEM revealed that the lactobacilli cells attached and bound to the surface of okara. Compared with FL, IL exhibited a significantly higher specific growth rate, shorter lag phase of growth, higher productions of lactic and acetic acids, a faster decrease in pH and increase in titrable acidity, and a higher soymilk viscosity. Similarly, IL in soymilk showed higher productions of daizein and genistein compared with the control. Compared with FL, IL showed reinforced resistance to simulatedgastric and intestinal stresses in vitro that included low pH, low pH plus pepsin, pancreatin, and bile salt. Our results indicate that okara is a new potential immobilization carrier to enhance the growth and glucosidic isoflavone bioconversion activities of L. plantarum in soymilk and improve cell survivability following simulated gastric and intestinal conditions. PMID:27867770

Characterization of hemicellulase and cellulase from the extremely thermophilic bacterium Caldicellulosiruptor owensensis and their potential application for bioconversion of lignocellulosic biomass without pretreatment.

PubMed

Peng, Xiaowei; Qiao, Weibo; Mi, Shuofu; Jia, Xiaojing; Su, Hong; Han, Yejun

2015-01-01

Pretreatment is currently the common approach for improving the efficiency of enzymatic hydrolysis on lignocellulose. However, the pretreatment process is expensive and will produce inhibitors such as furan derivatives and phenol derivatives. If the lignocellulosic biomass can efficiently be saccharified by enzymolysis without pretreatment, the bioconversion process would be simplified. The genus Caldicellulosiruptor, an obligatory anaerobic and extreme thermophile can produce a diverse set of glycoside hydrolases (GHs) for deconstruction of lignocellulosic biomass. It gives potential opportunities for improving the efficiency of converting native lignocellulosic biomass to fermentable sugars. Both of the extracellular (extra-) and intracellular (intra-) enzymes of C. owensensis cultivated on corncob xylan or xylose had cellulase (including endoglucanase, cellobiohydrolase and β-glucosidase) and hemicellulase (including xylanase, xylosidase, arabinofuranosidase and acetyl xylan esterase) activities. The enzymes of C. owensensis had high ability for degrading hemicellulose of native corn stover and corncob with the conversion rates of xylan 16.7 % and araban 60.0 %. Moreover, they had remarkable synergetic function with the commercial enzyme cocktail Cellic CTec2 (Novoyzmes). When the native corn stover and corncob were respectively, sequentially hydrolyzed by the extra-enzymes of C. owensensis and CTec2, the glucan conversion rates were 31.2 and 37.9 %,which were 1.7- and 1.9-fold of each control (hydrolyzed by CTec2 alone), whereas the glucan conversion rates of the steam-exploded corn stover and corncob hydrolyzed by CTec2 alone on the same loading rate were 38.2 and 39.6 %, respectively. These results show that hydrolysis by the extra-enzyme of C. owensensis made almost the same contribution as steam-exploded pretreatment on degradation of native lignocellulosic biomass. A new process for saccharification of lignocellulosic biomass by sequential hydrolysis is demonstrated in the present research, namely hyperthermal enzymolysis (70-80 °C) by enzymes of C. owensensis followed with mesothermal enzymolysis (50-55 °C) by commercial cellulase. This process has the advantages of no sugar loss, few inhibitors generation and consolidated with sterilization. The enzymes of C. owensensis demonstrated an enhanced ability to degrade the hemicellulose of native lignocellulose. The pretreatment and detoxification steps may be removed from the bioconversion process of the lignocellulosic biomass by using the enzymes from C. owensensis.

Soymilk residue (okara) as a natural immobilization carrier for Lactobacillus plantarum cells enhances soymilk fermentation, glucosidic isoflavone bioconversion, and cell survival under simulated gastric and intestinal conditions.

PubMed

Xiudong, Xia; Ying, Wang; Xiaoli, Liu; Ying, Li; Jianzhong, Zhou

2016-01-01

Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. However, artificial immobilization carriers are expensive and pose a high safety risk. Okara, a food-grade byproduct from soymilk production, is rich in prebiotics. Lactobacilli could provide health enhancing effects to the host. This study aimed to evaluate the potential of okara as a natural immobilizer for L. plantarum 70810 cells. The study also aimed to evaluate the effects of okara-immobilized L. plantarum 70810 cells (IL) on soymilk fermentation, glucosidic isoflavone bioconversion, and cell resistance to simulated gastric and intestinal stresses. Scanning electron microscopy (SEM) was used to show cells adherence to the surface of okara. Lactic acid, acetic acid and isoflavone analyses in unfermented and fermented soymilk were performed by HPLC with UV detection. Viability and growth kinetics of immobilized and free L. plantarum 70810 cells (FL) were followed during soymilk fermentation. Moreover, changes in pH, titrable acidity and viscosity were measured by conventional methods. For in vitro testing of simulated gastrointestinal resistance, fermented soymilk was inoculated with FL or IL and an aliquot incubated into acidic MRS broth which was conveniently prepared to simulate gastric, pancreatic juices and bile salts. Survival to simulated gastric and intestinal stresses was evaluated by plate count of colony forming units on MRS agar. SEM revealed that the lactobacilli cells attached and bound to the surface of okara. Compared with FL, IL exhibited a significantly higher specific growth rate, shorter lag phase of growth, higher productions of lactic and acetic acids, a faster decrease in pH and increase in titrable acidity, and a higher soymilk viscosity. Similarly, IL in soymilk showed higher productions of daizein and genistein compared with the control. Compared with FL, IL showed reinforced resistance to simulatedgastric and intestinal stresses in vitro that included low pH, low pH plus pepsin, pancreatin, and bile salt. Our results indicate that okara is a new potential immobilization carrier to enhance the growth and glucosidic isoflavone bioconversion activities of L. plantarum in soymilk and improve cell survivability following simulated gastric and intestinal conditions.

CNRS interdisciplinary research program for solar energy development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The contributions of CNRS to the French national solar energy R and D program are reviewed. The three principal processes in which solar radiation is converted into other, directly usable energy forms are discussed in detail. These include thermodynamic conversion, photovoltaic conversion, and bioconversion to produce a substitute fuel. Related research on insolation and the weather is mentioned and relations with the industrial sector are considered. French collaboration with other countries in solar energy is discussed.

Fungal synthesis of size-defined nanoparticles

NASA Astrophysics Data System (ADS)

Zielonka, Aleksandra; Klimek-Ochab, Magdalena

2017-12-01

Fungi with metabolic capacities can efficiently synthesize a wide range of nanoparticles (NPs). This biotransformation process and its product have extensive applications especially for industry, agriculture and medicine, where NPs size and shape is essential and can be defined by specific analytical methods. Fungi cultivation and further bioconversion can be fully controlled to obtain the desired nanoparticles. Additionally, this review provides information about the fungus F. oxysporum, which is able to synthesize the largest amount of different types of NPs.

Direct bioconversion of brown algae into ethanol by thermophilic bacterium Defluviitalea phaphyphila.

PubMed

Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

2016-01-01

Brown algae are promising feedstocks for biofuel production with inherent advantages of no structural lignin, high growth rate, and no competition for land and fresh water. However, it is difficult for one microorganism to convert all components of brown algae with different oxidoreduction potentials to ethanol. Defluviitalea phaphyphila Alg1 is the first characterized thermophilic bacterium capable of direct utilization of brown algae. Defluviitalea phaphyphila Alg1 can simultaneously utilize mannitol, glucose, and alginate to produce ethanol, and high ethanol yields of 0.47 g/g-mannitol, 0.44 g/g-glucose, and 0.3 g/g-alginate were obtained. A rational redox balance system under obligate anaerobic condition in fermenting brown algae was revealed in D. phaphyphila Alg1 through genome and redox analysis. The excess reducing equivalents produced from mannitol metabolism were equilibrated by oxidizing forces from alginate assimilation. Furthermore, D. phaphyphila Alg1 can directly utilize unpretreated kelp powder, and 10 g/L of ethanol was accumulated within 72 h with an ethanol yield of 0.25 g/g-kelp. Microscopic observation further demonstrated the deconstruction process of brown algae cell by D. phaphyphila Alg1. The integrated biomass deconstruction system of D. phaphyphila Alg1, as well as its high ethanol yield, provided us an excellent alternative for brown algae bioconversion at elevated temperature.

Uncovering the Potential of Termite Gut Microbiome for Lignocellulose Bioconversion in Anaerobic Batch Bioreactors

PubMed Central

Auer, Lucas; Lazuka, Adèle; Sillam-Dussès, David; Miambi, Edouard; O'Donohue, Michael; Hernandez-Raquet, Guillermina

2017-01-01

Termites are xylophages, being able to digest a wide variety of lignocellulosic biomass including wood with high lignin content. This ability to feed on recalcitrant plant material is the result of complex symbiotic relationships, which involve termite-specific gut microbiomes. Therefore, these represent a potential source of microorganisms for the bioconversion of lignocellulose in bioprocesses targeting the production of carboxylates. In this study, gut microbiomes of four termite species were studied for their capacity to degrade wheat straw and produce carboxylates in controlled bioreactors. All of the gut microbiomes successfully degraded lignocellulose and up to 45% w/w of wheat straw degradation was observed, with the Nasutitermes ephratae gut-microbiome displaying the highest levels of wheat straw degradation, carboxylate production and enzymatic activity. Comparing the 16S rRNA gene diversity of the initial gut inocula to the bacterial communities in lignocellulose degradation bioreactors revealed important changes in community diversity. In particular, taxa such as Spirochaetes and Fibrobacteres that were highly abundant in the initial gut inocula were replaced by Firmicutes and Proteobacteria at the end of incubation in wheat straw bioreactors. Overall, this study demonstrates that termite-gut microbiomes constitute a reservoir of lignocellulose-degrading bacteria that can be harnessed in artificial conditions for biomass conversion processes that lead to the production of useful molecules. PMID:29312279

Tapping the Bioactivity Potential of Residual Stream from Its Pretreatments May Be a Green Strategy for Low-Cost Bioconversion of Rice Straw.

PubMed

Chen, Xingxuan; Wang, Xiahui; Xue, Yiyun; Zhang, Tian-Ao; Hu, Jiajun; Tsang, Yiu Fai; Gao, Min-Tian

2018-04-16

In this study, it was found that the residual stream from pretreatments of rice straw exhibited high antioxidant activity. Assays based on the Folin-Ciocalteu colorimetric method confirmed that the residual stream contained large amounts of phenolic compounds. Three antioxidant assays were employed to evaluate the bioactivity of the residual stream. Strong linear correlations existed among the release of phenolic compounds, saccharification efficiency, and antioxidant activity. The alkaline pretreatment provided a much greater release of phenolic compounds, especially phenolic acids, compared to the acid pretreatment, and consequently, it had stronger linear correlations than the acid pretreatment. Antibacterial experiments demonstrated the ability of the phenolic compounds in the residual stream to inhibit the growth of microorganisms, indicating the potential of these compounds as antimicrobial agents. To discuss the possibility of the co-production of antimicrobial agents and biofuels/biochemicals, both acid and alkaline pretreatments were optimized using response surface methodology. Under the optimal conditions, 285.7 g glucose could be produced from 1 kg rice straw with the co-production of 3.84 g FA and 6.98 g p-CA after alkaline pretreatment. These results show that the recovery of phenolic compounds from the residual stream could be a green strategy for the low-cost bioconversion of rice straw.

Bioconversion of natural gas to liquid fuel: opportunities and challenges.

PubMed

Fei, Qiang; Guarnieri, Michael T; Tao, Ling; Laurens, Lieve M L; Dowe, Nancy; Pienkos, Philip T

2014-01-01

Natural gas is a mixture of low molecular weight hydrocarbon gases that can be generated from either fossil or anthropogenic resources. Although natural gas is used as a transportation fuel, constraints in storage, relatively low energy content (MJ/L), and delivery have limited widespread adoption. Advanced utilization of natural gas has been explored for biofuel production by microorganisms. In recent years, the aerobic bioconversion of natural gas (or primarily the methane content of natural gas) into liquid fuels (Bio-GTL) by biocatalysts (methanotrophs) has gained increasing attention as a promising alternative for drop-in biofuel production. Methanotrophic bacteria are capable of converting methane into microbial lipids, which can in turn be converted into renewable diesel via a hydrotreating process. In this paper, biodiversity, catalytic properties and key enzymes and pathways of these microbes are summarized. Bioprocess technologies are discussed based upon existing literature, including cultivation conditions, fermentation modes, bioreactor design, and lipid extraction and upgrading. This review also outlines the potential of Bio-GTL using methane as an alternative carbon source as well as the major challenges and future research needs of microbial lipid accumulation derived from methane, key performance index, and techno-economic analysis. An analysis of raw material costs suggests that methane-derived diesel fuel has the potential to be competitive with petroleum-derived diesel. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Characterization of hydrocortisone biometabolites and 18S rRNA gene in Chlamydomonas reinhardtii cultures.

PubMed

Ghasemi, Younes; Rasoul-Amini, Sara; Morowvat, Mohammad Hossein; Raee, Mohammad Javad; Ghoshoon, Mohammad Bagher; Nouri, Fatemeh; Negintaji, Narges; Parvizi, Rezvan; Mosavi-Azam, Seyed Bagher

2008-10-31

A unicellular microalga, Chlamydomonas reinhardtii, was isolated from rice paddy-field soil and water samples and used in the biotransformation of hydrocortisone (1). This strain has not been previously tested for steroid bioconversion. Fermentation was carried out in BG-11 medium supplemented with 0.05% substrate at 25 degrees C for 14 days of incubation. The products obtained were chromatographically purified and characterized using spectroscopic methods. 11b,17 beta-Dihydroxyandrost-4-en-3-one (2), 11 beta-hydroxyandrost-4-en-3,17-dione (3), 11 beta,17 alpha,20 beta,21-tetrahydroxypregn-4-en-3-one (4) and prednisolone (5) were the main products of the bioconversion. The observed bioreaction features were the side chain degradation of the substrate to give compounds 2 and 3 and the 20-ketone reduction and 1,2-dehydrogenation affording compounds 4 and 5, respectively. A time course study showed the accumulation of product 2 from the second day of the fermentation and of compounds 3, 4 and 5 from the third day. All the metabolites reached their maximum concentration in seven days. Microalgal 18S rRNA gene was also amplified by PCR. PCR products were sequenced to confirm their authenticity as 18S rRNA gene of microalgae. The result of PCR blasted with other sequenced microalgae in NCBI showed 100% homology to the 18S small subunit rRNA of two Chlamydomonas reinhardtii spp.

Developments toward large-scale bacterial bioprocesses in the presence of bulk amounts of organic solvents.

PubMed

Schmid, A; Kollmer, A; Mathys, R G; Witholt, B

1998-08-01

Many pseudomonads and other bacteria can grow on aliphatic and aromatic hydrocarbons that occur in the environment. We are examining the potential of such organisms as biocatalysts for the oxidation of a variety of substituted aliphatic and aromatic compounds. To attain a high production rate of oxidation products via such biotransformations, we have focused on two-liquid phase culture systems. In these systems, cells are grown in liquid media consisting of an aqueous phase containing water-soluble growth substrates and droplets of a water-immicible organic solvent containing bioconversion substrates and products. For industrial applications of such two-liquid phase processes, several questions remain. What are the maximum rates at which apolar compounds can be transferred from the apolar phase to cells growing in the aqueous phase, i.e., what are the maximum space-time yields attainable in two-liquid phase fermentations under practical conditions? What does an efficient downstream processing of two-liquid phase medium involve? What safety regimes should be considered in working with flammable organic solvents? Can elevated pressure be used to increase oxygen transfer? Based on answers to these questions, we have recently developed a high-pressure, explosion-proof bioreactor system with Bioengineering AG (Wald, Switzerland), which will be installed in our pilot plant and used to explore two-liquid phase bioconversions at a pilot scale.

Grain sorghum is a viable feedstock for ethanol production.

PubMed

Wang, D; Bean, S; McLaren, J; Seib, P; Madl, R; Tuinstra, M; Shi, Y; Lenz, M; Wu, X; Zhao, R

2008-05-01

Sorghum is a major cereal crop in the USA. However, sorghum has been underutilized as a renewable feedstock for bioenergy. The goal of this research was to improve the bioconversion efficiency for biofuels and biobased products from processed sorghum. The main focus was to understand the relationship among "genetics-structure-function-conversion" and the key factors impacting ethanol production, as well as to develop an energy life cycle analysis model (ELCAM) to quantify and prioritize the saving potential from factors identified in this research. Genetic lines with extremely high and low ethanol fermentation efficiency and some specific attributes that may be manipulated to improve the bioconversion rate of sorghum were identified. In general, ethanol yield increased as starch content increased. However, no linear relationship between starch content and fermentation efficiency was found. Key factors affecting the ethanol fermentation efficiency of sorghum include protein digestibility, level of extractable proteins, protein and starch interaction, mash viscosity, amount of phenolic compounds, ratio of amylose to amylopectin, and formation of amylose-lipid complexes in the mash. A platform ELCAM with a base case showed a positive net energy value (NEV) = 25,500 Btu/gal EtOH. ELCAM cases were used to identify factors that most impact sorghum use. For example, a yield increase of 40 bu/ac resulted in NEV increasing from 7 million to 12 million Btu/ac. An 8% increase in starch provided an incremental 1.2 million Btu/ac.

Improving Biomethane Production and Mass Bioconversion of Corn Stover Anaerobic Digestion by Adding NaOH Pretreatment and Trace Elements

PubMed Central

Liu, ChunMei; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Zhu, BaoNing; Li, XiuJin

2015-01-01

This research applied sodium hydroxide (NaOH) pretreatment and trace elements to improve biomethane production when using corn stover for anaerobic digestion. Full-factor experimental tests identified the best combination of trace elements with the NaOH pretreatment, indicating that the best combination was with 1.0, 0.4, and 0.4 mg·L−1·d−1 of elements Fe, Co, and Ni, respectively. The cumulative biomethane production adding NaOH pretreatment and trace elements was 11,367 mL; total solid bioconversion rate was 55.7%, which was 41.8%–62.2% higher than with NaOH-pretreatment alone and 22.2%–56.3% higher than with untreated corn stover. The best combination was obtained 5–9 days shorter than T90 and maintained good system operation stability. Only a fraction of the trace elements in the best combination was present in the resulting solution; more than 85% of the total amounts added were transferred into the solid fraction. Adding 0.897 g of Fe, 0.389 g of Co, and 0.349 g of Ni satisfied anaerobic digestion needs and enhanced biological activity at the beginning of the operation. The results showed that NaOH pretreatment and adding trace elements improve corn stover biodegradability and enhance biomethane production. PMID:26137469

Biosynthesis of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate by carbonyl reductase from Rhodosporidium toruloides in mono and biphasic media.

PubMed

Liu, Zhi-Qiang; Wu, Lin; Zheng, Ling; Wang, Wen-Zhong; Zhang, Xiao-Jian; Jin, Li-Qun; Zheng, Yu-Guo

2018-02-01

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is the key intermediate for synthesis of atorvastatin and rosuvastatin. Carbonyl reductase exhibits excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) to synthesize (3R,5S)-CDHH. In this study, a whole cell biosynthesis reaction system to produce (3R,5S)-CDHH was constructed in organic solvents. A solution of 10% (v/v) Tween-80 was introduced to the reaction system as a co-solvent, which greatly enhanced biotransformation process, giving 98.9% yield, >99% ee and 1.8-fold higher space time yield in 5 h bioconversion of 1 M (S)-CHOH, compared with 98.7% yield and >99% ee in 9 h bioconversion of a purely aqueous reaction system. Moreover, a water-octanol biphasic reaction system was built and 20% of octanol was added as reservoir of substrate resulting in 98% yield, >99% ee and 4.08 mmol L -1  h -1  g -1 (wet cell weight) space time yield. This study paved a way for the whole cell biosynthesis of (3R,5S)-CDHH in mono and biphasic media. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of process performance, energy consumption and microbiota characterization in a ceramic membrane bioreactor for ex-situ biomethanation of H2 and CO2.

PubMed

Alfaro, Natalia; Fdz-Polanco, María; Fdz-Polanco, Fernando; Díaz, Israel

2018-06-01

The performance of a pilot ceramic membrane bioreactor for the bioconversion of H 2 and CO 2 to bioCH 4 was evaluated in thermophilic conditions. The loading rate was between 10 and 30 m 3  H 2 /m 3 reactor  d and the system transformed 95% of H 2 fed. The highest methane yield found was 0.22 m 3  CH 4 /m 3  H 2 , close to the maximum stoichiometric value (0.25 m 3  CH 4 /m 3  H 2 ) thus indicating that archaeas employed almost all H 2 transferred to produce CH 4 . k L a value of 268 h -1 was reached at 30 m 3  H 2 /m 3 reactor  d. DGGE and FISH revealed a remarkable archaeas increase related to the selection-effect of H 2 on community composition over time. Methanothermobacter thermautotrophicus was the archaea found with high level of similarity. This study verified the successful application of membrane technology to efficiently transfer H 2 from gas to the liquid phase, the development of a hydrogenotrophic community from a conventional thermophilic sludge and the technical feasibility of the bioconversion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bioconversion of Natural Gas to Liquid Fuel. Opportunities and Challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fei, Qiang; Guarnieri, Michael T.; Tao, Ling

2014-05-01

Natural gas is a mixture of low molecular weight hydrocarbon gases that can be generated from either fossil or anthropogenic resources. Although natural gas is used as a transportation fuel, constraints in storage, relatively low energy content (MJ/L), and delivery have limited widespread adoption. Advanced utilization of natural gas has been explored for biofuel production by microorganisms. In recent years, the aerobic bioconversion of natural gas (or primarily the methane content of natural gas) into liquid fuels (Bio-GTL) by biocatalysts (methanotrophs) has gained increasing attention as a promising alternative for drop-in biofuel production. Moreover, methanotrophic bacteria are capable of convertingmore » methane into microbial lipids, which can in turn be converted into renewable diesel via a hydrotreating process. In this paper, biodiversity, catalytic properties and key enzymes and pathways of these microbes are summarized. Bioprocess technologies are discussed based upon existing literature, including cultivation conditions, fermentation modes, bioreactor design, and lipid extraction and upgrading. Our review also outlines the potential of Bio-GTL using methane as an alternative carbon source as well as the major challenges and future research needs of microbial lipid accumulation derived from methane, key performance index, and techno-economic analysis. An analysis of raw material costs suggests that methane-derived diesel fuel has the potential to be competitive with petroleum-derived diesel.« less

Bioconversion of natural gas to liquid fuel: Opportunities and challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fei, Q; Guarnieri, MT; Tao, L

2014-05-01

Natural gas is a mixture of low molecular weight hydrocarbon gases that can be generated from either fossil or anthropogenic resources. Although natural gas is used as a transportation fuel, constraints in storage, relatively low energy content (MJ/L), and delivery have limited widespread adoption. Advanced utilization of natural gas has been explored for biofuel production by microorganisms. In recent years, the aerobic bioconversion of natural gas (or primarily the methane content of natural gas) into liquid fuels (Bio-GTL) by biocatalysts (methanotrophs) has gained increasing attention as a promising alternative for drop-in biofuel production. Methanotrophic bacteria are capable of converting methanemore » into microbial lipids, which can in turn be converted into renewable diesel via a hydrotreating process. In this paper, biodiversity, catalytic properties and key enzymes and pathways of these microbes are summarized. Bioprocess technologies are discussed based upon existing literature, including cultivation conditions, fermentation modes, bioreactor design, and lipid extraction and upgrading. This review also outlines the potential of Bio-GTL using methane as an alternative carbon source as well as the major challenges and future research needs of microbial lipid accumulation derived from methane, key performance index, and techno-economic analysis. An analysis of raw material costs suggests that methane-derived diesel fuel has the potential to be competitive with petroleum-derived diesel. (C) 2014 The Authors. Published by Elsevier Inc.« less

Lipase-catalyzed production of short-chain acids terpenyl esters of interest to the food industry.

PubMed

Laboret, F; Perraud, R

1999-12-01

The production of low molecular weight esters as flavor compounds by biotechnological processes has a potential interest for the food industry. The use of natural available substrates and enzymes is an essential part of the process design, because the products may obtain natural label. In this study, direct esterification of citronellol and geraniol with short-chain fatty acids catalyzed by free lipase from Mucor miehei was performed with high yields in n-hexane. The effects of the acid:alcohol ratio on the bioconversion rate of increasing chain length esters was investigated. To reach the optimum yield, substrates and enzyme concentration were determined. The inhibiting effects of acid are strongly attenuated by reducing the quantity of acid and increasing the amount of enzyme in media following the optimum values. Improvements have been made to increase the ester purity. The consumption of excess substrate by adding calculated amounts of acid gives a 10% yield enhancement, and leads to 100% pure terpenyl esters. The first steps to a scale-up application were attempted using a reactor that allowed us to produce ester quantities up to 100 cm3. Separation and purification of the products were treated with success, underlining the lipase stability and efficiency under the conditions of this study. The ability to recover the enzyme, and reusing it in bioconversions, plays a major role in reducing the cost of the overall process.

Fermentation Products of Solvent Tolerant Marine Bacterium Moraxella spp. MB1 and Its Biotechnological Applications in Salicylic Acid Bioconversion

PubMed Central

Wahidullah, Solimabi; Naik, Deepak N.; Devi, Prabha

2013-01-01

As part of a proactive approach to environmental protection, emerging issues with potential impact on the environment is the subject of ongoing investigation. One emerging area of environmental research concerns pharmaceuticals like salicylic acid, which is the main metabolite of various analgesics including aspirin. It is a common component of sewage effluent and also an intermediate in the degradation pathway of various aromatic compounds which are introduced in the marine environment as pollutants. In this study, biotransformation products of salicylic acid by seaweed, Bryopsis plumosa, associated marine bacterium, Moraxella spp. MB1, have been investigated. Phenol, conjugates of phenol and hydroxy cinnamic acid derivatives (coumaroyl, caffeoyl, feruloyl and trihydroxy cinnamyl) with salicylic acid (3–8) were identified as the bioconversion products by electrospray ionization mass spectrometry. These results show that the microorganism do not degrade phenolic acid but catalyses oxygen dependent transformations without ring cleavage. The degradation of salicylic acid is known to proceed either via gentisic acid pathway or catechol pathway but this is the first report of biotransformation of salicylic acid into cinnamates, without ring cleavage. Besides cinnamic acid derivatives (9–12), metabolites produced by the bacterium include antimicrobial indole (13) and β-carbolines, norharman (14), harman (15) and methyl derivative (16), which are beneficial to the host and the environment. PMID:24391802

Application of a chitosan-immobilized Talaromyces thermophilus lipase to a batch biodiesel production from waste frying oils.

PubMed

Romdhane, Ines Belhaj-Ben; Romdhane, Zamen Ben; Bouzid, Maha; Gargouri, Ali; Belghith, Hafedh

2013-12-01

Waste frying oil, which not only harms people's health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.

[Effect of ensilage on bioconversion of switchgrass to ethanol based on liquid hot water pretreatment].

PubMed

Wu, Wentao; Ju, Meiting; Liu, Jinpeng; Liu, Boqun

2016-04-25

Ensilage is a traditional way of preserving fresh biomass. However, in order to apply ensilage to the ethanol biorefinery, two parameters need to be evaluated: quantity and quality changes of the biomass; and its effects on bioconversion process. To study these two aspects, switchgrass harvested on three different time points (Early, mid and late fall) were used as feedstock. The early fall harvested biomass was ensiled at 5 moisture levels ranging from 30% to 70%. Silage of 40% moisture and 3 other raw switchgrass were pretreated with liquid hot water, followed by enzymatic hydrolysis as well as simultaneous saccharification and fermentation. After 21 days storage pH values of all silages decreased below 4.0 and the dry matter losses were less than 2.0%, and structural sugars contents did not change dramatically. Liquid hot water caused more hemicellulose dissolution in the silage than in unensiled switchgrass. However, ensilage also increased the risk of releasing more sugar degradation products; After enzymatic hydrolysis, silage obtained higher total glucose, xylose and galactose yields than raw materials; After simultaneous saccharification and fermentation, ethanol concentration in silage was 12.1 g/L, higher than the unensiled switchgrass (10.3 g/L, 9.7 g/L and 10.6 g/L for early, mid and late fall respectively). Our results suggest that ensilage helps increase pretreatment efficiency and sugar yield, which increases final ethanol production.

Production of bioethanol by direct bioconversion of oil-palm industrial effluent in a stirred-tank bioreactor.

PubMed

Alam, Md Zahangir; Kabbashi, Nassereldeen A; Hussin, S Nahdatul I S

2009-06-01

The purpose of this study was to evaluate the feasibility of producing bioethanol from palm-oil mill effluent generated by the oil-palm industries through direct bioconversion process. The bioethanol production was carried out through the treatment of compatible mixed cultures such as Thrichoderma harzianum, Phanerochaete chrysosporium, Mucor hiemalis, and yeast, Saccharomyces cerevisiae. Simultaneous inoculation of T. harzianum and S. cerevisiae was found to be the mixed culture that yielded the highest ethanol production (4% v/v or 31.6 g/l). Statistical optimization was carried out to determine the operating conditions of the stirred-tank bioreactor for maximum bioethanol production by a two-level fractional factorial design with a single central point. The factors involved were oxygen saturation level (pO(2)%), temperature, and pH. A polynomial regression model was developed using the experimental data including the linear, quadratic, and interaction effects. Statistical analysis showed that the maximum ethanol production of 4.6% (v/v) or 36.3 g/l was achieved at a temperature of 32 degrees C, pH of 6, and pO(2) of 30%. The results of the model validation test under the developed optimum process conditions indicated that the maximum production was increased from 4.6% (v/v) to 6.5% (v/v) or 51.3 g/l with 89.1% chemical-oxygen-demand removal.

Bioconversion of lignocellulosic pretreatment effluent via oleaginous Rhodococcus opacus DSM 1069

DOE PAGES

Wells, Jr., Tyrone; Wei, Zhen; Ragauskas, Arthur J.

2014-11-26

Rhodococcus opacus DSM 1069 utilized pine organosolv pretreatment effluent as a sole carbon and energy source for 120 h at 1.5 w/v% solids concentration and accumulated a maximum of 26.99 ± 2.88% of its cellular dry weight in oils composed of oleic, palmitic, and stearic fatty acids. Here, these results establish the potential for lignocellulosic pretreatment effluent as a feedstock for microbial biodiesel production via oleaginous R. opacus and an interesting route for biorefinery waste stream optimization.

Interaction of Microbial and Abiotic Processes in Soil Leading to the (Bio)Conversion and Ultimate Attenuation of New Insensitive Munitions Compounds

DTIC Science & Technology

2016-12-30

Toxicity is expressed as percentage of toxicant- free activity 125 Figure 4.12-1. Panel A: (Bio)transformation pathways of DNAN in anaerobic incubations...O-demethylation of the methoxy group was confirmed by formation of formaldehye. Cell free extracts of the Bacillus culture yielded formation of 2...periodically until the production of methane became constant in the toxicant- free controls. The maximum specific methanogenic activity of the

Cofermentation of Glucose, Xylose, and Cellobiose by the Beetle-Associated Yeast Spathaspora passalidarum

PubMed Central

Long, Tanya M.; Su, Yi-Kai; Headman, Jennifer; Higbee, Alan; Willis, Laura B.

2012-01-01

Fermentation of cellulosic and hemicellulosic sugars from biomass could resolve food-versus-fuel conflicts inherent in the bioconversion of grains. However, the inability to coferment glucose and xylose is a major challenge to the economical use of lignocellulose as a feedstock. Simultaneous cofermentation of glucose, xylose, and cellobiose is problematic for most microbes because glucose represses utilization of the other saccharides. Surprisingly, the ascomycetous, beetle-associated yeast Spathaspora passalidarum, which ferments xylose and cellobiose natively, can also coferment these two sugars in the presence of 30 g/liter glucose. S. passalidarum simultaneously assimilates glucose and xylose aerobically, it simultaneously coferments glucose, cellobiose, and xylose with an ethanol yield of 0.42 g/g, and it has a specific ethanol production rate on xylose more than 3 times that of the corresponding rate on glucose. Moreover, an adapted strain of S. passalidarum produced 39 g/liter ethanol with a yield of 0.37 g/g sugars from a hardwood hydrolysate. Metabolome analysis of S. passalidarum before onset and during the fermentations of glucose and xylose showed that the flux of glycolytic intermediates is significantly higher on xylose than on glucose. The high affinity of its xylose reductase activities for NADH and xylose combined with allosteric activation of glycolysis probably accounts in part for its unusual capacities. These features make S. passalidarum very attractive for studying regulatory mechanisms enabling bioconversion of lignocellulosic materials by yeasts. PMID:22636012

Determination of optimal biomass pretreatment strategies for biofuel production: investigation of relationships between surface-exposed polysaccharides and their enzymatic conversion using carbohydrate-binding modules.

PubMed

Khatri, Vinay; Meddeb-Mouelhi, Fatma; Adjallé, Kokou; Barnabé, Simon; Beauregard, Marc

2018-01-01

Pretreatment of lignocellulosic biomass (LCB) is a key step for its efficient bioconversion into ethanol. Determining the best pretreatment and its parameters requires monitoring its impacts on the biomass material. Here, we used fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay to study the relationship between surface-exposed polysaccharides and enzymatic hydrolysis of LCB. Our results indicated that alkali extrusion pretreatment led to the highest hydrolysis rates for alfalfa stover, cattail stems and flax shives, despite its lower lignin removal efficiency compared to alkali pretreatment. Corn crop residues were more sensitive to alkali pretreatments, leading to higher hydrolysis rates. A clear relationship was consistently observed between total surface-exposed cellulose detected by the FTCM-depletion assay and biomass enzymatic hydrolysis. Comparison of bioconversion yield and total composition analysis (by NREL/TP-510-42618) of LCB prior to or after pretreatments did not show any close relationship. Lignin removal efficiency and total cellulose content (by NREL/TP-510-42618) led to an unreliable prediction of enzymatic polysaccharide hydrolysis. Fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay provided direct evidence that cellulose exposure is the key determinant of hydrolysis yield. The clear and robust relationships that were observed between the cellulose accessibility by FTCM probes and enzymatic hydrolysis rates change could be evolved into a powerful prediction tool that might help develop optimal biomass pretreatment strategies for biofuel production.

A novel bioconversion for value-added products from food waste using Musca domestica.

PubMed

Niu, Yi; Zheng, Dong; Yao, Binghua; Cai, Zizhe; Zhao, Zhimin; Wu, Shengqing; Cong, Peiqing; Yang, Depo

2017-03-01

Food waste, as a major part of the municipal solid waste has been generated increasingly worldwide. Efficient and feasible utilization of this waste material for productivity process is significant for both economical and environmental reasons. In the present study, Musca domestica larva was used as the carrier to conduct a bioconversion with food waste to get the value-added maggot protein, oil and organic fertilizers. Methods of adult flies rearing, culture medium adjuvant selection, maggot culture conditions, stocking density and the valorization of the waste have been explored. From the experimental results, every 1000g culture mediums (700g food waste and 300g adjuvant) could be disposed by 1.5g M. domestica eggs under proper culture conditions after emergence in just 4days, 42.95±0.25% of which had been consumed and the culture medium residues could be used as good organic fertilizers, accompanying with the food waste consumption, ∼53.08g dried maggots that contained 57.06±2.19% protein and 15.07±2.03% oil had been produced. The maggot protein for its outstanding pharmacological activities is regarded as a good raw material in the field of medicine and animal feeding. Meanwhile, the maggot oil represents a potential alternative feedstock for biodiesel production. In our study, the maggot biodiesel was obtained after the procedure of transesterification reaction with methanol and the productivity was 87.71%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biohydrogen production in a continuous stirred tank bioreactor from synthesis gas by anaerobic photosynthetic bacterium: Rhodopirillum rubrum.

PubMed

Younesi, Habibollah; Najafpour, Ghasem; Ku Ismail, Ku Syahidah; Mohamed, Abdul Rahman; Kamaruddin, Azlina Harun

2008-05-01

Hydrogen may be considered a potential fuel for the future since it is carbon-free and oxidized to water as a combustion product. Bioconversion of synthesis gas (syngas) to hydrogen was demonstrated in continuous stirred tank bioreactor (CSTBR) utilizing acetate as a carbon source. An anaerobic photosynthetic bacterium, Rhodospirillum rubrum catalyzed water-gas shift reaction which was applied for the bioconversion of syngas to hydrogen. The continuous fermentation of syngas in the bioreactor was continuously operated at various gas flow rates and agitation speeds, for the period of two months. The gas flow rates were varied from 5 to 14 ml/min. The agitation speeds were increasingly altered in the range of 150-500 rpm. The pH and temperature of the bioreactor was set at 6.5 and 30 degrees C. The liquid flow rate was kept constant at 0.65 ml/min for the duration of 60 days. The inlet acetate concentration was fed at 4 g/l into the bioreactor. The hydrogen production rate and yield were 16+/-1.1 mmol g(-1)cell h(-1) and 87+/-2.4% at fixed agitation speed of 500 rpm and syngas flow rate of 14 ml/min, respectively. The mass transfer coefficient (KLa) at this condition was approximately 72.8h(-1). This new approach, using a biocatalyst was considered as an alternative method of conventional Fischer-Tropsch synthetic reactions, which were able to convert syngas into hydrogen.

Cascade catalysis in membranes with enzyme immobilization for multi-enzymatic conversion of CO2 to methanol.

PubMed

Luo, Jianquan; Meyer, Anne S; Mateiu, R V; Pinelo, Manuel

2015-05-25

Facile co-immobilization of enzymes is highly desirable for bioconversion methods involving multi-enzymatic cascade reactions. Here we show for the first time that three enzymes can be immobilized in flat-sheet polymeric membranes simultaneously or separately by simple pressure-driven filtration (i.e. by directing membrane fouling formation), without any addition of organic solvent. Such co-immobilization and sequential immobilization systems were examined for the production of methanol from CO2 with formate dehydrogenase (FDH), formaldehyde dehydrogenase (FaldDH) and alcohol dehydrogenase (ADH). Enzyme activity was fully retained by this non-covalent immobilization strategy. The two immobilization systems had similar catalytic efficiencies because the second reaction (formic acid→formaldehyde) catalyzed by FaldDH was found to be the cascade bottleneck (a threshold substrate concentration was required). Moreover, the trade-off between the mitigation of product inhibition and low substrate concentration for the adjacent enzymes probably made the co-immobilization meaningless. Thus, sequential immobilization could be used for multi-enzymatic cascade reactions, as it allowed the operational conditions for each single step to be optimized, not only during the enzyme immobilization but also during the reaction process, and the pressure-driven mass transfer (flow-through mode) could overcome the diffusion resistance between enzymes. This study not only offers a green and facile immobilization method for multi-enzymatic cascade systems, but also reveals the reaction bottleneck and provides possible solutions for the bioconversion of CO2 to methanol. Copyright © 2015 Elsevier B.V. All rights reserved.

Bioconversion of hybrid poplar to ethanol and co-products using an organosolv fractionation process: optimization of process yields.

PubMed

Pan, Xuejun; Gilkes, Neil; Kadla, John; Pye, Kendall; Saka, Shiro; Gregg, David; Ehara, Katsunobu; Xie, Dan; Lam, Dexter; Saddler, Jack

2006-08-05

An organosolv process involving extraction with hot aqueous ethanol has been evaluated for bioconversion of hybrid poplar to ethanol. The process resulted in fractionation of poplar chips into a cellulose-rich solids fraction, an ethanol organosolv lignin (EOL) fraction, and a water-soluble fraction containing hemicellulosic sugars, sugar breakdown products, degraded lignin, and other components. The influence of four independent process variables (temperature, time, catalyst dose, and ethanol concentration) on product yields was analyzed over a broad range using a small composite design and response surface methodology. Center point conditions for the composite design (180 degrees C, 60 min, 1.25% H(2)SO(4), and 60% ethanol), yielded a solids fraction containing approximately 88% of the cellulose present in the untreated poplar. Approximately 82% of the total cellulose in the untreated poplar was recovered as monomeric glucose after hydrolysis of the solids fraction for 24 h using a low enzyme loading (20 filter paper units of cellulase/g cellulose); approximately 85% was recovered after 48 h hydrolysis. Total recovery of xylose (soluble and insoluble) was equivalent to approximately 72% of the xylose present in untreated wood. Approximately 74% of the lignin in untreated wood was recovered as EOL. Other cooking conditions resulted in either similar or inferior product yields although the distribution of components between the various fractions differed markedly. Data analysis generated regression models that describe process responses for any combination of the four variables. (c) 2006 Wiley Periodicals, Inc.

Helically agitated mixing in dry dilute acid pretreatment enhances the bioconversion of corn stover into ethanol

PubMed Central

2014-01-01

Background Dry dilute acid pretreatment at extremely high solids loading of lignocellulose materials demonstrated promising advantages of no waste water generation, less sugar loss, and low steam consumption while maintaining high hydrolysis yield. However, the routine pretreatment reactor without mixing apparatus was found not suitable for dry pretreatment operation because of poor mixing and mass transfer. In this study, helically agitated mixing was introduced into the dry dilute acid pretreatment of corn stover and its effect on pretreatment efficiency, inhibitor generation, sugar production, and bioconversion efficiency through simultaneous saccharification and ethanol fermentation (SSF) were evaluated. Results The overall cellulose conversion taking account of cellulose loss in pretreatment was used to evaluate the efficiency of pretreatment. The two-phase computational fluid dynamics (CFD) model on dry pretreatment was established and applied to analyze the mixing mechanism. The results showed that the pretreatment efficiency was significantly improved and the inhibitor generation was reduced by the helically agitated mixing, compared to the dry pretreatment without mixing: the ethanol titer and yield from cellulose in the SSF reached 56.20 g/L and 69.43% at the 30% solids loading and 15 FPU/DM cellulase dosage, respectively, corresponding to a 26.5% increase in ethanol titer and 17.2% increase in ethanol yield at the same fermentation conditions. Conclusions The advantage of helically agitated mixing may provide a prototype of dry dilute acid pretreatment processing for future commercial-scale production of cellulosic ethanol. PMID:24387051

Bioconversion of Pinoresinol Diglucoside and Pinoresinol from Substrates in the Phenylpropanoid Pathway by Resting Cells of Phomopsis sp.XP-8

PubMed Central

Zhang, Yan; Shi, Junling; Liu, Laping; Gao, Zhenhong; Che, Jinxin; Shao, Dongyan; Liu, Yanlin

2015-01-01

Pinoresinol diglucoside (PDG) and pinoresinol (Pin) are normally produced by plant cells via the phenylpropanoid pathway. This study reveals the existence of a related pathway in Phomopsis sp. XP-8, a PDG-producing fungal strain isolated from the bark of the Tu-chung tree (Eucommiaulmoides Oliv.). After addition of 0.15 g/L glucose to Phomopsis sp. XP-8, PDG and Pin formed when phenylalanine, tyrosine, leucine, cinnamic acid, and p-coumaric acid were used as the substrates respectively. No PDG formed in the absence of glucose, but Pin was detected after addition of all these substrates except leucine. In all systems in the presence of glucose, production of PDG and/or Pin and the accumulation of phenylalanine, cinnamic acid, or p-coumaric acid correlated directly with added substrate in a time- and substrate concentration- dependent manner. After analysis of products produced after addition of each substrate, the mass flow sequence for PDG and Pin biosynthesis was defined as: glucose to phenylalanine, phenylalanine to cinnamic acid, then to p-coumaric acid, and finally to Pin or PDG. During the bioconversion, the activities of four key enzymes in the phenylpropanoid pathway were also determined and correlated with accumulation of their corresponding products. PDG production by Phomopsis sp. exhibits greater efficiency and cost effectiveness than the currently-used plant-based system and will pave the way for large scale production of PDG and/or Pin for medical applications. PMID:26331720

Oligosaccharides in feces of breast- and formula-fed babies.

PubMed

Albrecht, Simone; Schols, Henk A; van Zoeren, Diny; van Lingen, Richard A; Groot Jebbink, Liesbeth J M; van den Heuvel, Ellen G H M; Voragen, Alphons G J; Gruppen, Harry

2011-10-18

So far, little is known on the fate of oligosaccharides in the colon of breast- and formula-fed babies. Using capillary electrophoresis with laser induced fluorescence detector coupled to a mass spectrometer (CE-LIF-MS(n)), we studied the fecal oligosaccharide profiles of 27 two-month-old breast-, formula- and mixed-fed preterm babies. The interpretation of the complex oligosaccharide profiles was facilitated by beforehand clustering the CE-LIF data points by agglomerative hierarchical clustering (AHC). In the feces of breast-fed babies, characteristic human milk oligosaccharide (HMO) profiles, showing genetic fingerprints known for human milk of secretors and non-secretors, were recognized. Alternatively, advanced degradation and bioconversion of HMOs, resulting in an accumulation of acidic HMOs or HMO bioconversion products was observed. Independent of the prebiotic supplementation of the formula with galactooligosaccharides (GOS) at the level used, similar oligosaccharide profiles of low peak abundance were obtained for formula-fed babies. Feeding influences the presence of diet-related oligosaccharides in baby feces and gastrointestinal adaptation plays an important role herein. Four fecal oligosaccharides, characterized as HexNAc-Hex-Hex, Hex-[Fuc]-HexNAc-Hex, HexNAc-[Fuc]-Hex-Hex and HexNAc-[Fuc]-Hex-HexNAc-Hex-Hex, highlighted an active gastrointestinal metabolization of the feeding-related oligosaccharides. Their presence was linked to the gastrointestinal mucus layer and the blood-group determinant oligosaccharides therein, which are characteristic for the host's genotype. Copyright © 2011 Elsevier Ltd. All rights reserved.

Enantioselective synthesis of (R)-phenylephrine by Serratia marcescens BCRC10948 cells that homologously express SM_SDR.

PubMed

Kuan, Yi-Chia; Xu, Yue-Bin; Wang, Wen-Ching; Yang, Ming-Te

2018-03-01

A short-chain dehydrogenase/reductase from Serratia marcescens BCRC10948, SM_SDR, has been cloned and expressed in Escherichia coli for the bioconversion of 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) to (R)-phenylephrine[(R)-PE]. However, only 5.11mM (R)-PE was obtained from 10mM HPMAE after a 9h conversion in the previous report. To improve the biocatalytic efficiency, the homologous expression of the SM_SDR in S. marcescens BCRC10948 was achieved using the T5 promoter for expression. By using 2% glycerol as carbon source, we found that 8.00±0.15mM of (R)-PE with more than 99% enantiomeric excess was produced from 10mM HPMAE after 12h conversion at 30°C and pH 7.0. More importantly, by using 50mM HPMAE as the substrate, 23.78±0.84mM of (R)-PE was produced after a 12h conversion with the productivity and the conversion yield of 1.98mmol (R)-PE/lh and 47.50%, respectively. The recombinant S. marcescens cells could be recycled 6 times for the production of (R)-PE, and the bioconversion efficiency remained at 85% when compared to that at the first cycle. Our data indicated that a high conversion efficiency of HPMAE to (R)-PE could be achieved using S. marcescens BCRC10948 cells that homologously express the SM_SDR. Copyright © 2017 Elsevier Inc. All rights reserved.

Bioconversion of D-galactose to D-tagatose: continuous packed bed reaction with an immobilized thermostable L-arabinose isomerase and efficient purification by selective microbial degradation.

PubMed

Liang, Min; Chen, Min; Liu, Xinying; Zhai, Yafei; Liu, Xian-wei; Zhang, Houcheng; Xiao, Min; Wang, Peng

2012-02-01

The continuous enzymatic conversion of D-galactose to D-tagatose with an immobilized thermostable L-arabinose isomerase in packed-bed reactor and a novel method for D-tagatose purification were studied. L-arabinose isomerase from Thermoanaerobacter mathranii (TMAI) was recombinantly overexpressed and immobilized in calcium alginate. The effects of pH and temperature on D-tagatose production reaction catalyzed by free and immobilized TMAI were investigated. The optimal condition for free enzyme was pH 8.0, 60°C, 5 mM MnCl(2). However, that for immobilized enzyme was pH 7.5, 75°C, 5 mM MnCl(2). In addition, the catalytic activity of immobilized enzyme at high temperature and low pH was significantly improved compared with free enzyme. The optimum reaction yield with immobilized TMAI increased by four percentage points to 43.9% compared with that of free TMAI. The highest productivity of 10 g/L h was achieved with the yield of 23.3%. Continuous production was performed at 70°C; after 168 h, the reaction yield was still above 30%. The resultant syrup was then incubated with Saccharomyces cerevisiae L1 cells. The selective degradation of D-galactose was achieved, obtaining D-tagatose with the purity above 95%. The established production and separation methods further potentiate the industrial production of D-tagatose via bioconversion and biopurification processes.

Biotechnological production of pharmaceuticals and biopharmaceuticals in plant cell and organ cultures.

PubMed

Hidalgo, Diego; Sanchez, Raul; Lalaleo, Liliana; Bonfill, Mercedes; Corchete, Purificacion; Palazon, Javier

2018-03-09

Plant biofactories are biotechnological platforms based on plant cell and organ cultures used for the production of pharmaceuticals and biopharmaceuticals, although to date only a few of these systems have successfully been implemented at an industrial level. Metabolic engineering is possibly the most straightforward strategy to boost pharmaceutical production in plant biofactories, but social opposition to the use of GMOs means empirical approaches are still being used. Plant secondary metabolism involves thousands of different enzymes, some of which catalyze specific reactions, giving one product from a particular substrate, whereas others can yield multiple products from the same substrate. This trait opens plant cell biofactories to new applications, in which the natural metabolic machinery of plants can be harnessed for the bioconversion of phytochemicals or even the production of new bioactive compounds. Synthetic biological pipelines involving the bioconversion of natural substrates into products with a high market value may be established by the heterologous expression of target metabolic genes in model plants. To summarize the state of the art of plant biofactories and their applications for the pipeline production of cosme-, pharma- and biopharmaceuticals. In order to demonstrate the great potential of plant biofactories for multiple applications in the biotechnological production of pharmaceuticals and biopharmaceuticals, this review broadly covers the following: plant biofactories based on cell and hairy root cultures; secondary metabolite production; biotransformation reactions; metabolic engineering tools applied in plant biofactories; and biopharmaceutical production. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Acute toxicity and genotoxicity of fermented traditional medicine oyaksungi-san.

PubMed

Park, Hwayong; Hwang, Youn-Hwan; Ma, Jin Yeul

2017-06-01

The traditional medicine oyaksungi-san (OY) has been prescribed in East Asia for hundreds of years for the treatment of stroke, paralysis, and ataxia. OY also has therapeutic effects on arthralgia, myalgia, and rheumatoid arthritis, and recent studies have shown its protective effects against apoptosis of hippocampal cells and its anti-inflammatory effects on the peripheral blood cells of patient with cerebral infarction. Many studies have explored the use of traditional medicine and herb materials in the development of safe, novel, and effective pharmaceuticals with fewer side effects. These efforts commonly adopt a bioconversion tool for fermentation with beneficial microbes. However, only pharmaceuticals with high levels of safety and low levels of toxicity can be used in healthcare system. OY water extract was fermented with Lactobacillus and assayed for acute toxicity and genotoxicity. Single dose acute toxicity, bacterial reverse mutation, chromosome aberrations, and micronucleus were observed and assayed in rats, histidine/tryptophan auxotrophic bacteria, Chinese hamster ovary fibroblast cells, and mice bone marrow cells, respectively. All the experimental animals showed no abnormal behavior, clinical signs, body weight increases, or mortality. In the bacterial cultures, no revertant colonies were observed. Morphological and numerical chromosomal aberrations were not found in all metaphases examined. Frequency of induced micronuclei was not significantly increased in all doses applied. As a whole, no acute toxicity or genotoxicity were observed in all the assays examined. Therefore, fermented OY is considered to be a safe material that can be used for development of complementary and alternative medicine using bioconversion.

Bridging the gap between feedstock growers and users: the study of a coppice poplar-based biorefinery.

PubMed

Dou, Chang; Gustafson, Rick; Bura, Renata

2018-01-01

In the biofuel industry, land productivity is important to feedstock growers and conversion process product yield is important to the biorefinery. The crop productivity, however, may not positively correlate with bioconversion yield. Therefore, it is important to evaluate sugar yield and biomass productivity. In this study, 2-year-old poplar trees harvested in the first coppice cycle, including one low-productivity hybrid and one high-productivity hybrid, were collected from two poplar tree farms. Through steam pretreatment and enzymatic hydrolysis, the bioconversion yields of low- and high-productivity poplar hybrids were compared for both sites. The low-productivity hybrids had 9-19% higher sugar yields than the high-productivity hybrids, although they have the similar chemical composition. Economic calculations show the impact on the plantation and biorefinery of using the two feedstocks. Growing a high-productivity hybrid means the land owner would use 11-26% less land (which could be used for other crops) or collect $2.53-$3.46 MM/year extra revenue from the surplus feedstock. On the other side, the biorefinery would receive 5-10% additional revenue using the low-productivity hybrid. We propose a business model based on the integration of the plantation and the biorefinery. In this model, different feedstocks are assessed using a metric of product tonnage per unit land per year. Use of this new economic metric bridges the gap between feedstock growers and users to maximize the overall production efficiency.

Valorization of CH4 emissions into high-added-value products: Assessing the production of ectoine coupled with CH4 abatement.

PubMed

Cantera, Sara; Lebrero, Raquel; Sadornil, Lidia; García-Encina, Pedro A; Muñoz, Raúl

2016-11-01

This study assessed an innovative strategy for the valorization of dilute methane emissions based on the bio-conversion of CH4 (the second most important greenhouse gas (GHG)) into ectoine by the methanotrophic ectoine-producing strain Methylomicrobium alcaliphilum 20 Z. The influence of CH4 (2-20%), Cu(2+) (0.05-50 μM) and NaCl (0-9%) concentration as well as temperature (25-35 °C) on ectoine synthesis and specific CH4 biodegradation rate was evaluated for the first time. Concentrations of 20% CH4 (at 3% NaCl, 0.05 μM Cu(2+), 25 °C) and 6% NaCl (at 4% CH4, 0.05 μM Cu(2+), 25 °C) supported the maximum intra-cellular ectoine production yield (31.0 ±1.7 and 66.9 ±4.2 mg g biomass(-1), respectively). On the other hand, extra-cellular ectoine concentrations of up to 4.7 ± 0.1 mg L(-1) were detected at high Cu(2+)concentrations (50 μM), despite this methanotroph has not been previously classified as an ectoine-excreting strain. This research demonstrated the feasibility of the bio-conversion of dilute emissions of methane into high-added value products in an attempt to develop a sustainable GHG bioeconomy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioconversion of distillers' grains hydrolysates to advanced biofuels by an Escherichia coli co-culture.

PubMed

Liu, Fang; Wu, Weihua; Tran-Gyamfi, Mary B; Jaryenneh, James D; Zhuang, Xun; Davis, Ryan W

2017-11-09

First generation bioethanol production utilizes the starch fraction of maize, which accounts for approximately 60% of the ash-free dry weight of the grain. Scale-up of this technology for fuels applications has resulted in a massive supply of distillers' grains with solubles (DGS) coproduct, which is rich in cellulosic polysaccharides and protein. It was surmised that DGS would be rapidly adopted for animal feed applications, however, this has not been observed based on inconsistency of the product stream and other logistics-related risks, especially toxigenic contaminants. Therefore, efficient valorization of DGS for production of petroleum displacing products will significantly improve the techno-economic feasibility and net energy return of the established starch bioethanol process. In this study, we demonstrate 'one-pot' bioconversion of the protein and carbohydrate fractions of a DGS hydrolysate into C4 and C5 fusel alcohols through development of a microbial consortium incorporating two engineered Escherichia coli biocatalyst strains. The carbohydrate conversion strain E. coli BLF2 was constructed from the wild type E. coli strain B and showed improved capability to produce fusel alcohols from hexose and pentose sugars. Up to 12 g/L fusel alcohols was produced from glucose or xylose synthetic medium by E. coli BLF2. The second strain, E. coli AY3, was dedicated for utilization of proteins in the hydrolysates to produce mixed C4 and C5 alcohols. To maximize conversion yield by the co-culture, the inoculation ratio between the two strains was optimized. The co-culture with an inoculation ratio of 1:1.5 of E. coli BLF2 and AY3 achieved the highest total fusel alcohol titer of up to 10.3 g/L from DGS hydrolysates. The engineered E. coli co-culture system was shown to be similarly applicable for biofuel production from other biomass sources, including algae hydrolysates. Furthermore, the co-culture population dynamics revealed by quantitative PCR analysis indicated that despite the growth rate difference between the two strains, co-culturing didn't compromise the growth of each strain. The q-PCR analysis also demonstrated that fermentation with an appropriate initial inoculation ratio of the two strains was important to achieve a balanced co-culture population which resulted in higher total fuel titer. The efficient conversion of DGS hydrolysates into fusel alcohols will significantly improve the feasibility of the first generation bioethanol process. The integrated carbohydrate and protein conversion platform developed here is applicable for the bioconversion of a variety of biomass feedstocks rich in sugars and proteins.

Bioconversion of plant carotenoids to vitamin A in Filipino school-aged children varies inversely with vitamin A status.

PubMed

Ribaya-Mercado, J D; Solon, F S; Solon, M A; Cabal-Barza, M A; Perfecto, C S; Tang, G; Solon, J A; Fjeld, C R; Russell, R M

2000-08-01

It is important to understand the factors affecting strategies to improve the vitamin A status of populations. We reported previously that a 3-d deuterated-retinol-dilution (DRD) procedure might be used to indicate total body stores of vitamin A. We studied the ability of 3-d DRD to detect changes in the body pool size of vitamin A and the effect of vitamin A status on the bioconversion of plant carotenoids to vitamin A. Two separate, unrelated studies were conducted in 7-13-y-old children with poor or marginal serum retinol concentrations (0.32-0.93 micromol/L) by feeding them controlled diets daily for 5 d/wk for 12 wk, after treatment with an anthelmintic drug. In school 1 (n = 27), lunch and 2 snacks that were provided at school contained 2258 retinol equivalents/d (mostly from orange fruit and vegetables) and 5.3 MJ/d from 33 g fat, 37 g protein, and 209 g carbohydrates; in school 2 (n = 25), 2 snacks provided 2.5 MJ/d from 9.4 g fat, 9.6 g protein, and 119 g carbohydrates, but no carotenes. In school 1, mean serum beta-carotene increased from 0.12 to 0.62 micromol/L (P = 0.0001) and serum retinol increased from 0.68 to 1. 06 micromol/L (P = 0.0001). In school 2, serum beta-carotene increased from 0.06 to 0.11 micromol/L (P = 0.0001) and serum retinol increased from 0.66 to 0.86 micromol/L (P = 0.0001). In school 1, but not school 2, improvement in serum retinol varied inversely with baseline retinol (r = -0.38, P = 0.048). In both schools, 3-d DRD showed reductions in the ratio of serum deuterated to nondeuterated retinol (D:H retinol) postintervention, denoting improvements in vitamin A status; the higher D:H retinol (ie, the poorer the status) at baseline, the greater the reduction in D:H retinol postintervention (school 1: r = -0.99, P = 0.0001; school 2: r = -0.89, P = 0.0001). Three-day DRD can detect changes in the body pool size of vitamin A, although a predictive equation to quantitate total body stores of vitamin A with the use of 3-d data needs to be developed. Bioconversion of plant carotenoids to vitamin A varies inversely with vitamin A status; improvement in status after dietary interventions is strongly influenced by total body stores of vitamin A and is influenced little or not at all by serum retinol.

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, R.; Tao, L.; Tan, E. C. D.

2013-10-01

This report describes one potential conversion process to hydrocarbon products by way of biological conversion of lingnocellulosic-dervied sugars. The process design converts biomass to a hydrocarbon intermediate, a free fatty acid, using dilute-acid pretreatement, enzymatic saccharification, and bioconversion. Ancillary areas--feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combusion, and utilities--are also included in the design.

Efficient bioconversion of organic wastes to high optical activity of l-lactic acid stimulated by cathode in mixed microbial consortium.

PubMed

Xue, Gang; Lai, Sizhou; Li, Xiang; Zhang, Wenjuan; You, Jiguang; Chen, Hong; Qian, Yajie; Gao, Pin; Liu, Zhenhong; Liu, Yanan

2017-12-12

Lactic acid is one of the emerging top biomass derived platform chemicals that can be fermented from organic wastes. This study evaluated the potential of Cathodic Electro-Fermentation (CEF) as a novel approach to enhance the yield of high optical activity (OA) of l-lactic acid from organic wastes using mixed microbial consortium. The fermentation process was stimulated through the cathode applied with -100 mV versus standard hydrogen electrode (SHE), which contributed to 4.73 times higher lactic acid productivity (0.6578 g L -1 h -1 ) compared to that in the open circuit control (0.1392 g L -1 h -1 ), and an improved OA of l-lactic acid was also observed (42.3% vs. 3.6% of the open circuit control). The study elucidated that the optimal voltage at -100 mV promoted the conversion of pyruvate to l-lactate by 77.9% compared to the Blank, which triggered the generation of l-lactic acid to occur rapidly even at low concentration of pyruvate. The significant variation of microbial community in family- and genus-level distributions were observed in CEF system. Furthermore, the open-circuit operation test demonstrated that the cathode providing in-situ electron supply was essential to achieve high efficient bioconversion of organic wastes to lactic acid. Our work highlights the feasibility of CEF to steer high value-added fermentation products deriving from organic wastes by the mixed microbial consortium. Copyright © 2017 Elsevier Ltd. All rights reserved.

In vitro bioconversion of chitin to pyruvate with thermophilic enzymes.

PubMed

Honda, Kohsuke; Kimura, Keisuke; Ninh, Pham Huynh; Taniguchi, Hironori; Okano, Kenji; Ohtake, Hisao

2017-09-01

Chitin is the second most abundant organic compound on the planet and thus has been regarded as an alternative resource to petroleum feedstocks. One of the key challenges in the biological conversion of biomass-derived polysaccharides, such as cellulose and chitin, is to close the gap between optimum temperatures for enzymatic saccharification and microbial fermentation and to implement them in a single bioreactor. To address this issue, in the present study, we aimed to perform an in vitro, one-pot bioconversion of chitin to pyruvate, which is a precursor of a wide range of useful metabolites. Twelve thermophilic enzymes, including that for NAD + regeneration, were heterologously produced in Escherichia coli and semi-purified by heat treatment of the crude extract of recombinant cells. When the experimentally decided concentrations of enzymes were incubated with 0.5 mg mL -1 colloidal chitin (equivalent to 2.5 mM N-acetylglucosamine unit) and an adequate set of cofactors at 70°C, 0.62 mM pyruvate was produced in 5 h. Despite the use of a cofactor-balanced pathway, determination of the pool sizes of cofactors showed a rapid decrease in ATP concentration, most probably due to the thermally stable ATP-degrading enzyme(s) derived from the host cell. Integration of an additional enzyme set of thermophilic adenylate kinase and polyphosphate kinase led to the deceleration of ATP degradation, and the final product titer was improved to 2.1 mM. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Metabolic responses in Candida tropicalis to complex inhibitors during xylitol bioconversion.

PubMed

Wang, Shizeng; Li, Hao; Fan, Xiaoguang; Zhang, Jingkun; Tang, Pingwah; Yuan, Qipeng

2015-09-01

During xylitol fermentation, Candida tropicalis is often inhibited by inhibitors in hemicellulose hydrolysate. The mechanisms involved in the metabolic responses to inhibitor stress and the resistances to inhibitors are still not clear. To understand the inhibition mechanisms and the metabolic responses to inhibitors, a GC/MS-based metabolomics approach was performed on C. tropicalis treated with and without complex inhibitors (CI, including furfural, phenol and acetic acid). Partial least squares discriminant analysis was used to determine the metabolic variability between CI-treated groups and control groups, and 25 metabolites were identified as possible entities responsible for the discrimination caused by inhibitors. We found that xylose uptake rate and xylitol oxidation rate were promoted by CI treatment. Metabolomics analysis showed that the flux from xylulose to pentose phosphate pathway increased, and tricarboxylic acid cycle was disturbed by CI. Moreover, the changes in levels of 1,3-propanediol, trehalose, saturated fatty acids and amino acids showed different mechanisms involved in metabolic responses to inhibitor stress. The increase of 1,3-propanediol was considered to be correlated with regulating redox balance and osmoregulation. The increase of trehalose might play a role in protein stabilization and cellular membranes protection. Saturated fatty acids could cause the decrease of membrane fluidity and make the plasma membrane rigid to maintain the integrity of plasma membrane. The deeper understanding of the inhibition mechanisms and the metabolic responses to inhibitors will provide us with more information on the metabolism regulation during xylitol bioconversion and the construction of industrial strains with inhibitor tolerance for better utilization of bioresource. Copyright © 2015 Elsevier Inc. All rights reserved.

Efficient butanol-ethanol (B-E) production from carbon monoxide fermentation by Clostridium carboxidivorans.

PubMed

Fernández-Naveira, Ánxela; Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2016-04-01

The fermentation of waste gases rich in carbon monoxide using acetogens is an efficient way to obtain valuable biofuels like ethanol and butanol. Different experiments were carried out with the bacterial species Clostridium carboxidivorans as biocatalyst. In batch assays with no pH regulation, after complete substrate exhaustion, acetic acid, butyric acid, and ethanol were detected while only negligible butanol production was observed. On the other side, in bioreactors, with continuous carbon monoxide supply and pH regulation, both C2 and C4 fatty acids were initially formed as well as ethanol and butanol at concentrations never reported before for this type of anaerobic bioconversion of gaseous C1 compounds, showing that the operating conditions significantly affect the metabolic fermentation profile and butanol accumulation. Maximum ethanol and butanol concentrations in the bioreactors were obtained at pH 5.75, reaching values of 5.55 and 2.66 g/L, respectively. The alcohols were produced both from CO fermentation as well as from the bioconversion of previously accumulated acetic and butyric acids, resulting in low residual concentrations of such acids at the end of the bioreactor experiments. CO consumption was often around 50% and reached up to more than 80%. Maximum specific rates of ethanol and butanol production were reached at pH 4.75, with values of 0.16 g/h*g of biomass and 0.07 g/h*g of biomass, respectively, demonstrating that a low pH was more favorable to solventogenesis in this process, although it negatively affects biomass growth which does also play a role in the final alcohol titer.

Shiitake Medicinal Mushroom, Lentinus edodes (Higher Basidiomycetes) Productivity and Lignocellulolytic Enzyme Profiles during Wheat Straw and Tree Leaf Bioconversion.

PubMed

Elisashvili, Vladimir; Kachlishvili, Eva; Asatiani, Mikheil D

2015-01-01

Two commercial strains of Lentinus edodes have been comparatively evaluated for their productivity and lignocellulolytic enzyme profiles in mushroom cultivation using wheat straw or tree leaves as the growth substrates. Both substrates are profitable for recycling into shiitake fruit bodies. L. edodes 3715 gave the lowest yield of mushroom during tree leaves bioconversion with the biological efficiency (BE) 74.8% while the L. edodes 3721 BE achieved 83.4%. Cultivation of shiitake on wheat straw, especially in the presence of additional nitrogen source, increased the L. edodes 3721 BE to 92-95.3% owing to the high hydrolases activity and favorable conditions. Despite the quantitative variations, each strain of L. edodes had a similar pattern for secreting enzymes into the wheat straw and tree leaves. The mushrooms laccase and MnP activities were high during substrate colonization and declined rapidly during primordia appearance and fruit body development. While oxidase activity decreased, during the same period cellulases and xylanase activity raised sharply. Both cellulase and xylanase activity peaked at the mature fruit body stage. When mushrooms again shifted to the vegetative growth, oxidase activity gradually increased, whereas the hydrolases activity dropped rapidly. The MnP, CMCase, and FP activities of L. edodes 3721 during cultivation on wheat straw were higher than those during mushroom growth on tree leaves whereas the laccase activity was rather higher in fermentation of tree leaves. Enrichment of wheat straw with an additional nitrogen source rather favored to laccase, MnP, and FPA secretion during the vegetative stage of the L. edodes 3721 growth.

The prospects of cellulase-producing bacteria for the bioconversion of lignocellulosic biomass.

PubMed

Maki, Miranda; Leung, Kam Tin; Qin, Wensheng

2009-07-29

Lignocellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. However, the biorefining process remains economically unfeasible due to a lack of biocatalysts that can overcome costly hurdles such as cooling from high temperature, pumping of oxygen/stirring, and, neutralization from acidic or basic pH. The extreme environmental resistance of bacteria permits screening and isolation of novel cellulases to help overcome these challenges. Rapid, efficient cellulase screening techniques, using cellulase assays and metagenomic libraries, are a must. Rare cellulases with activities on soluble and crystalline cellulose have been isolated from strains of Paenibacillus and Bacillus and shown to have high thermostability and/or activity over a wide pH spectrum. While novel cellulases from strains like Cellulomonas flavigena and Terendinibacter turnerae, produce multifunctional cellulases with broader substrate utilization. These enzymes offer a framework for enhancement of cellulases including: specific activity, thermalstability, or end-product inhibition. In addition, anaerobic bacteria like the clostridia offer potential due to species capable of producing compound multienzyme complexes called cellulosomes. Cellulosomes provide synergy and close proximity of enzymes to substrate, increasing activity towards crystalline cellulose. This has lead to the construction of designer cellulosomes enhanced for specific substrate activity. Furthermore, cellulosome-producing Clostridium thermocellum and its ability to ferment sugars to ethanol; its amenability to co-culture and, recent advances in genetic engineering, offer a promising future in biofuels. The exploitation of bacteria in the search for improved enzymes or strategies provides a means to upgrade feasibility for lignocellulosic biomass conversion, ultimately providing means to a 'greener' technology.

The prospects of cellulase-producing bacteria for the bioconversion of lignocellulosic biomass

PubMed Central

Maki, Miranda; Leung, Kam Tin; Qin, Wensheng

2009-01-01

Lignocellulosic biomass is a renewable and abundant resource with great potential for bioconversion to value-added bioproducts. However, the biorefining process remains economically unfeasible due to a lack of biocatalysts that can overcome costly hurdles such as cooling from high temperature, pumping of oxygen/stirring, and, neutralization from acidic or basic pH. The extreme environmental resistance of bacteria permits screening and isolation of novel cellulases to help overcome these challenges. Rapid, efficient cellulase screening techniques, using cellulase assays and metagenomic libraries, are a must. Rare cellulases with activities on soluble and crystalline cellulose have been isolated from strains of Paenibacillus and Bacillus and shown to have high thermostability and/or activity over a wide pH spectrum. While novel cellulases from strains like Cellulomonas flavigena and Terendinibacter turnerae, produce multifunctional cellulases with broader substrate utilization. These enzymes offer a framework for enhancement of cellulases including: specific activity, thermalstability, or end-product inhibition. In addition, anaerobic bacteria like the clostridia offer potential due to species capable of producing compound multienzyme complexes called cellulosomes. Cellulosomes provide synergy and close proximity of enzymes to substrate, increasing activity towards crystalline cellulose. This has lead to the construction of designer cellulosomes enhanced for specific substrate activity. Furthermore, cellulosome-producing Clostridium thermocellum and its ability to ferment sugars to ethanol; its amenability to co-culture and, recent advances in genetic engineering, offer a promising future in biofuels. The exploitation of bacteria in the search for improved enzymes or strategies provides a means to upgrade feasibility for lignocellulosic biomass conversion, ultimately providing means to a 'greener' technology. PMID:19680472

Deletion of the Saccharomyces cerevisiae ARO8 gene, encoding an aromatic amino acid transaminase, enhances phenylethanol production from glucose.

PubMed

Romagnoli, Gabriele; Knijnenburg, Theo A; Liti, Gianni; Louis, Edward J; Pronk, Jack T; Daran, Jean-Marc

2015-01-01

Phenylethanol has a characteristic rose-like aroma that makes it a popular ingredient in foods, beverages and cosmetics. Microbial production of phenylethanol currently relies on whole-cell bioconversion of phenylalanine with yeasts that harbour an Ehrlich pathway for phenylalanine catabolism. Complete biosynthesis of phenylethanol from a cheap carbon source, such as glucose, provides an economically attractive alternative for phenylalanine bioconversion. In this study, synthetic genetic array (SGA) screening was applied to identify genes involved in regulation of phenylethanol synthesis in Saccharomyces cerevisiae. The screen focused on transcriptional regulation of ARO10, which encodes the major decarboxylase involved in conversion of phenylpyruvate to phenylethanol. A deletion in ARO8, which encodes an aromatic amino acid transaminase, was found to underlie the transcriptional upregulation of ARO10 during growth, with ammonium sulphate as the sole nitrogen source. Physiological characterization revealed that the aro8Δ mutation led to substantial changes in the absolute and relative intracellular concentrations of amino acids. Moreover, deletion of ARO8 led to de novo production of phenylethanol during growth on a glucose synthetic medium with ammonium as the sole nitrogen source. The aro8Δ mutation also stimulated phenylethanol production when combined with other, previously documented, mutations that deregulate aromatic amino acid biosynthesis in S. cerevisiae. The resulting engineered S. cerevisiae strain produced >3 mm phenylethanol from glucose during growth on a simple synthetic medium. The strong impact of a transaminase deletion on intracellular amino acid concentrations opens new possibilities for yeast-based production of amino acid-derived products. Copyright © 2014 John Wiley & Sons, Ltd.

Biodegradation and bioconversion of coals by fungi: Technical report No. 6 for the period December 1, 1986-February 28, 1987. [Candida sp. , Cunninghamella sp. , Acremonium sp. , and Trametes versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ward, B.

We continued our tests for biosolubilization activity on lignite, subbituminous, and bituminous coals, using both surface solubilization and agar diffusion assays for selected lignite-solubilizing strains challenged with untreated and treated coals shown in earlier tests to be resistant to biosolubilization. These latter were subjected to treatments with heat or pressurized oxygen atmosphere, or to combinations of the same. We have observed biosolubilization of some weathered high-rank coals by some of the fungal isolates tested. 1 tab.

Large scale solubilization of coal and bioconversion to utilizable energy. Eleventh quarterly technical progress report, April 1, 1996--June 30, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishra, N.C.

1996-10-01

Neurospora has the capability to solubilize coal and the protein fraction accounting for this ability has been isolated. During this period the cola solubilizing activity (CSA) was fractionated and partially sequenced. The activity has been determined to be a tyrosinase and/or a phenol oxidase. The amino acid sequence of the protein was used to prepare oligonucleotides to identify the clone carrying Neurospora CSA. It is intended to clone the Neurospora gene into yeast, since yeast cannot solubilize coal, to further characterize the CSA.

From rumen to industry

PubMed Central

2012-01-01

The rumen is one of the most complicated and most fascinating microbial ecosystems in nature. A wide variety of microbial species, including bacteria, fungi and protozoa act together to bioconvert (ligno)cellulosic plant material into compounds, which can be taken up and metabolized by the ruminant. Thus, the rumen perfectly resembles a solution to a current industrial problem: the biorefinery, which aims at the bioconversion of lignocellulosic material into fuels and chemicals. We suggest to intensify the studies of the ruminal microbial ecosystem from an industrial microbiologists point of view in order to make use of this rich source of organisms and enzymes. PMID:22963386

From rumen to industry.

PubMed

Sauer, Michael; Marx, Hans; Mattanovich, Diethard

2012-09-10

The rumen is one of the most complicated and most fascinating microbial ecosystems in nature. A wide variety of microbial species, including bacteria, fungi and protozoa act together to bioconvert (ligno)cellulosic plant material into compounds, which can be taken up and metabolized by the ruminant. Thus, the rumen perfectly resembles a solution to a current industrial problem: the biorefinery, which aims at the bioconversion of lignocellulosic material into fuels and chemicals. We suggest to intensify the studies of the ruminal microbial ecosystem from an industrial microbiologists point of view in order to make use of this rich source of organisms and enzymes.

Optimization of process parameters for pilot-scale liquid-state bioconversion of sewage sludge by mixed fungal inoculation.

PubMed

Rahman, Roshanida A; Molla, Abul Hossain; Barghash, Hind F A; Fakhru'l-Razi, Ahmadun

2016-01-01

Liquid-state bioconversion (LSB) technique has great potential for application in bioremediation of sewage sludge. The purpose of this study is to determine the optimum level of LSB process of sewage sludge treatment by mixed fungal (Aspergillus niger and Penicillium corylophilum) inoculation in a pilot-scale bioreactor. The optimization of process factors was investigated using response surface methodology based on Box-Behnken design considering hydraulic retention time (HRT) and substrate influent concentration (S0) on nine responses for optimizing and fitted to the regression model. The optimum region was successfully depicted by optimized conditions, which was identified as the best fit for convenient multiple responses. The results from process verification were in close agreement with those obtained through predictions. Considering five runs of different conditions of HRT (low, medium and high 3.62, 6.13 and 8.27 days, respectively) with the range of S0 value (the highest 12.56 and the lowest 7.85 g L(-1)), it was monitored as the lower HRT was considered as the best option because it required minimum days of treatment than the others with influent concentration around 10 g L(-1). Therefore, optimum process factors of 3.62 days for HRT and 10.12 g L(-1) for S0 were identified as the best fit for LSB process and its performance was deviated by less than 5% in most of the cases compared to the predicted values. The recorded optimized results address a dynamic development in commercial-scale biological treatment of wastewater for safe and environment-friendly disposal in near future.

A high throughput screen for biomining cellulase activity from metagenomic libraries.

PubMed

Mewis, Keith; Taupp, Marcus; Hallam, Steven J

2011-02-01

Cellulose, the most abundant source of organic carbon on the planet, has wide-ranging industrial applications with increasing emphasis on biofuel production (1). Chemical methods to modify or degrade cellulose typically require strong acids and high temperatures. As such, enzymatic methods have become prominent in the bioconversion process. While the identification of active cellulases from bacterial and fungal isolates has been somewhat effective, the vast majority of microbes in nature resist laboratory cultivation. Environmental genomic, also known as metagenomic, screening approaches have great promise in bridging the cultivation gap in the search for novel bioconversion enzymes. Metagenomic screening approaches have successfully recovered novel cellulases from environments as varied as soils (2), buffalo rumen (3) and the termite hind-gut (4) using carboxymethylcellulose (CMC) agar plates stained with congo red dye (based on the method of Teather and Wood (5)). However, the CMC method is limited in throughput, is not quantitative and manifests a low signal to noise ratio (6). Other methods have been reported (7,8) but each use an agar plate-based assay, which is undesirable for high-throughput screening of large insert genomic libraries. Here we present a solution-based screen for cellulase activity using a chromogenic dinitrophenol (DNP)-cellobioside substrate (9). Our library was cloned into the pCC1 copy control fosmid to increase assay sensitivity through copy number induction (10). The method uses one-pot chemistry in 384-well microplates with the final readout provided as an absorbance measurement. This readout is quantitative, sensitive and automated with a throughput of up to 100X 384-well plates per day using a liquid handler and plate reader with attached stacking system.

Lignin-solubilizing ability of actinomycetes isolated from termite (Termitidae) gut.

PubMed Central

Pasti, M B; Pometto, A L; Nuti, M P; Crawford, D L

1990-01-01

The lignocellulose-degrading abilities of 11 novel actinomycete strains isolated from termite gut were determined and compared with that of the well-characterized actinomycete, Streptomyces viridosporus T7A. Lignocellulose bioconversion was followed by (i) monitoring the degradation of [14C]lignin- and [14C]cellulose-labeled phloem of Abies concolor to 14CO2 and 14C-labeled water-soluble products, (ii) determining lignocellulose, lignin, and carbohydrate losses resulting from growth on a lignocellulose substrate prepared from corn stalks (Zea mays), and (iii) quantifying production of a water-soluble lignin degradation intermediate (acid-precipitable polymeric lignin). The actinomycetes were all Streptomyces strains and could be placed into three groups, including a group of five strains that appear superior to S. viridosporus T7A in lignocellulose-degrading ability, three strains of approximately equal ability, and three strains of lesser ability. Strain A2 was clearly the superior and most effective lignocellulose decomposer of those tested. Of the assays used, total lignocellulose weight loss was most useful in determining overall bioconversion ability but not in identifying the best lignin-solubilizing strains. A screening procedure based on 14CO2 evolution from [14C-lignin]lignocellulose combined with measurement of acid-precipitable polymeric lignin yield was the most effective in identifying lignin-solubilizing strains. For the termite gut strains, the pH of the medium showed no increase after 3 weeks of growth on lignocellulose. This is markedly different from the pattern observed with S. viridosporus T7A, which raises the medium pH considerably. Production of extracellular peroxidases by the 11 strains and S. viridosporus T7A was followed for 5 days in liquid cultures.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2167628

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unuofin, F.O., E-mail: funmifrank2009@gmail.com; Mnkeni, P.N.S., E-mail: pmnkeni@ufh.ac.za

2014-11-15

Highlights: • Vermidegradation of RP-enriched waste mixtures is dependent on E. fetida stocking density. • A stocking density of 12.5 g-worms kg{sup -1} resulted in highly humified vermicomposts. • P release from RP-enriched waste vermicomposts increases with E. fetida stocking density. • RP-enriched waste vermicomposts had no inhibitory effect on seed germination. - Abstract: Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung andmore » rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg{sup −1} dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg{sup −1} resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg{sup −1} feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered.« less

Studying the rapid bioconversion of lignocellulosic sugars into ethanol using high cell density fermentations with cell recycle

PubMed Central

2014-01-01

Background The Rapid Bioconversion with Integrated recycle Technology (RaBIT) process reduces capital costs, processing times, and biocatalyst cost for biochemical conversion of cellulosic biomass to biofuels by reducing total bioprocessing time (enzymatic hydrolysis plus fermentation) to 48 h, increasing biofuel productivity (g/L/h) twofold, and recycling biocatalysts (enzymes and microbes) to the next cycle. To achieve these results, RaBIT utilizes 24-h high cell density fermentations along with cell recycling to solve the slow/incomplete xylose fermentation issue, which is critical for lignocellulosic biofuel fermentations. Previous studies utilizing similar fermentation conditions showed a decrease in xylose consumption when recycling cells into the next fermentation cycle. Eliminating this decrease is critical for RaBIT process effectiveness for high cycle counts. Results Nine different engineered microbial strains (including Saccharomyces cerevisiae strains, Scheffersomyces (Pichia) stipitis strains, Zymomonas mobilis 8b, and Escherichia coli KO11) were tested under RaBIT platform fermentations to determine their suitability for this platform. Fermentation conditions were then optimized for S. cerevisiae GLBRCY128. Three different nutrient sources (corn steep liquor, yeast extract, and wheat germ) were evaluated to improve xylose consumption by recycled cells. Capacitance readings were used to accurately measure viable cell mass profiles over five cycles. Conclusion The results showed that not all strains are capable of effectively performing the RaBIT process. Acceptable performance is largely correlated to the specific xylose consumption rate. Corn steep liquor was found to reduce the deleterious impacts of cell recycle and improve specific xylose consumption rates. The viable cell mass profiles indicated that reduction in specific xylose consumption rate, not a drop in viable cell mass, was the main cause for decreasing xylose consumption. PMID:24847379

Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes

PubMed Central

2012-01-01

The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC. In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production. PMID:22455837

Fermentation of lignocellulosic sugars to acetic acid by Moorella thermoacetica.

PubMed

Ehsanipour, Mandana; Suko, Azra Vajzovic; Bura, Renata

2016-06-01

A systematic study of bioconversion of lignocellulosic sugars to acetic acid by Moorella thermoacetica (strain ATCC 39073) was conducted. Four different water-soluble fractions (hydrolysates) obtained after steam pretreatment of lignocellulosic biomass were selected and fermented to acetic acid in batch fermentations. M. thermoacetica can effectively ferment xylose and glucose in hydrolysates from wheat straw, forest residues, switchgrass, and sugarcane straw to acetic acid. Xylose and glucose were completely utilized, with xylose being consumed first. M. thermoacetica consumed up to 62 % of arabinose, 49 % galactose and 66 % of mannose within 72 h of fermentation in the mixture of lignocellulosic sugars. The highest acetic acid yield was obtained from sugarcane straw hydrolysate, with 71 % of theoretical yield based on total sugars (17 g/L acetic acid from 24 g/L total sugars). The lowest acetic acid yield was observed in forest residues hydrolysate, with 39 % of theoretical yield based on total sugars (18 g/L acetic acid from 49 g/L total sugars). Process derived compounds from steam explosion pretreatment, including 5-hydroxymethylfurfural (0.4 g/L), furfural (0.1 g/L) and total phenolics (3 g/L), did not inhibit microbial growth and acetic acid production yield. This research identified two major factors that adversely affected acetic acid yield in all hydrolysates, especially in forest residues: (i) glucose to xylose ratio and (ii) incomplete consumption of arabinose, galactose and mannose. For efficient bioconversion of lignocellulosic sugars to acetic acid, it is imperative to have an appropriate balance of sugars in a hydrolysate. Hence, the choice of lignocellulosic biomass and steam pretreatment design are fundamental steps for the industrial application of this process.

Identification and production of local carotene-rich foods to combat vitamin A malnutrition.

PubMed

Solomons, N W; Bulux, J

1997-11-01

To address, with respect to improvement of human vitamin A status by dietary approaches, the three theoretical postulates that: 1) the most practical and economical manner to increase the amount of dietary vitamin A available to low-income persons in low-income nations is through plant sources of provitamin A carotenoids; 2) there will be constraints and limitation to the efficiency of a given intervention approach related to behavioural, cultural, biological and botanical considerations; and 3) the nature of these constraints and limitations must be understood, and then overcome where possible, to maximize the impact of such interventions on the vitamin A status of developing country populations. We review how local plant sources of provitamin A that would be acceptable for the at-risk populations and outline six settings and scenarios for the processing of carotene-rich foods: 1) cooking for hygiene; 2) long-term preservation; 3) compacting to reduce volume; 4) formulation for specific consumers; 5) improving bioavailability and bioconversion; and 6) to increase 'value added' in commerce. We describe our experiences in Guatemala (with sweet potato flakes), and those of others in the Caribbean, the African Sahel, and East Africa (with solar-drying for preservation of a variety of plants), and in Sri Lanka (with leaf concentrates) in promoting increased carotene-rich food intake, and the lessons learned from their evaluations. This overall approach to combatting endemic hypovitaminosis A in developing countries is evaluated within the constraints of: 1) the volumes of plant-based foods required to satisfy vitamin A requirements; and 2) the controversy over the true bioconversion efficiency of provitamin A from plant sources into the biologically-available active vitamin.

Amide-transforming activity of Streptomyces: possible application to the formation of hydroxy amides and aminoalcohols.

PubMed

Yamada, Shinya; Miyagawa, Taka-Aki; Yamada, Ren; Shiratori-Takano, Hatsumi; Sayo, Noboru; Saito, Takao; Takano, Hideaki; Beppu, Teruhiko; Ueda, Kenji

2013-07-01

To develop an efficient bioconversion process for amides, we screened our collection of Streptomyces strains, mostly obtained from soil, for effective transformers. Five strains, including the SY007 (NBRC 109343) and SY435 (NBRC 109344) of Streptomyces sp., exhibited marked conversion activities from the approximately 700 strains analyzed. These strains transformed diverse amide compounds such as N-acetyltetrahydroquinoline, N-benzoylpyrrolidine, and N-benzoylpiperidine into alcohols or N,O-acetals with high activity and regioselectivity. N,O-acetal was transformed into alcohol by serial tautomerization and reduction reactions. As such, Streptomyces spp. can potentially be used for the efficient preparation of hydroxy amides and aminoalcohols.

Fungal strains as catalysts for the biotransformation of halolactones by hydrolytic dehalogenation with the dimethylcyclohexane system.

PubMed

Grabarczyk, Małgorzata

2012-08-14

Bicyclic chloro-, bromo- and iodo-γ-lactones with dimethylcyclohexane rings were used as substrates for bioconversion by several fungal strains (Fusarium, Botrytis and Beauveria). Most of the selected microorganisms transformed these lactones by hydrolytic dehalogenation into the new compound cis-2-hydroxy-4,6-dimethyl-9-oxabicyclo[4.3.0]- nonan-8-one, mainly the (-)-isomer. When iodo-γ-lactone was used as the substrate, two products were observed: a hydroxy-γ-lactone and an unsaturated lactone. The structures of all substrates and products were established on the basis of their spectral data. The mechanism of dehalogenation of three halolactones was also studied.

Method for high specific bioproductivity of .alpha.,.omega.-alkanedicarboxylic acids

DOEpatents

Mobley, David Paul; Shank, Gary Keith

2000-01-01

This invention provides a low-cost method of producing .alpha.,.omega.-alkanedicarboxylic acids. Particular bioconversion conditions result in highly efficient conversion of fatty acid, fatty acid ester, or alkane substrates to diacids. Candida tropicalis AR40 or similar yeast strains are grown in a medium containing a carbon source and a nitrogen source at a temperature of 31.degree. C. to 38.degree. C., while additional carbon source is continuously added, until maximum cell growth is attained. Within 0-3 hours of this point, substrate is added to the culture to initiate conversion. An .alpha.,.omega.-alkanedicarboxylic acid made according to this method is also provided.

Biotransformation of tissue-specific hormone tibolone with fungal culture Trichothecium roseum

NASA Astrophysics Data System (ADS)

Shah, Syed Adnan Ali; Sultan, Sadia; Zaimi bin Mohd Noor, M.

2013-06-01

Whole cells based biotransformation is an important tool for bioconversion of steroids. It can be used to synthesize biologically potent compounds with diverse structures. Biotransformation of tissue-specific hormone tibolone (1) with Trichothecium roseum (ATCC 13411) has being carried out for the first time. Two new and three known metabolites 2-6 were isolated from fermentation of tibolone (1) with Trichothecium roseum and their structures were characterized by 2D NMR spectroscopy and mass spectrometry. The relative stereochemistry of new metabolites 5 and 6 was deduced by 2D NOESY experiments. The effect of cultures on tibolone structural modifications and time-course studies has also been conducted.

Enzymatic approaches to rare sugar production.

PubMed

Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

Rare sugars have recently attracted much attention because of their potential applications in the food, nutraceutical, and pharmaceutical industries. A systematic strategy for enzymatic production of rare sugars, named Izumoring, was developed >10years ago. The strategy consists of aldose-ketose isomerization, ketose C-3 epimerization, and monosaccharide oxidation-reduction. Recent development of the Izumoring strategy is reviewed herein, especially the genetic approaches to the improvement of rare sugar-producing enzymes and the applications of target-oriented bioconversion. In addition, novel non-Izumoring enzymatic approaches are also summarized, including enzymatic condensation, phosphorylation-dephosphorylation cascade reaction, aldose epimerization, ulosonic acid decarboxylation, and biosynthesis of rare disaccharides. Copyright © 2017 Elsevier Inc. All rights reserved.

Vanillin-bioconversion and bioengineering of the most popular plant flavor and its de novo biosynthesis in the vanilla orchid.

PubMed

Gallage, Nethaji J; Møller, Birger Lindberg

2015-01-01

In recent years, biotechnology-derived production of flavors and fragrances has expanded rapidly. The world's most popular flavor, vanillin, is no exception. This review outlines the current state of biotechnology-based vanillin synthesis with the use of ferulic acid, eugenol, and glucose as substrates and bacteria, fungi, and yeasts as microbial production hosts. The de novo biosynthetic pathway of vanillin in the vanilla orchid and the possible applied uses of this new knowledge in the biotechnology-derived and pod-based vanillin industries are also highlighted. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

A multidisciplinary research program directed toward utilization of solar energy through bioconversion of renewable resources

NASA Astrophysics Data System (ADS)

Finnerty, W. R.

1980-07-01

Cellulytic bacteria, cellobiose fermentors, sulfate-reducing bacteria and methanogenic bacteria were isolated from established anaerobic mesophilic and thermophilic cellulose methane fermentations and these isolates, plus known laboratory strains, were employed to partially reconstitute highly active cellulose fermentations. These mixed cultures are utilized as model systems to study the parameters required for maximum production of CH4, H2 and chemical feedstocks such as acetate, ethanol, propionate, etc., from cellulose. The physiology of these reconstituted cultures is investigated as regards cultural conditions, microbial types, inoculum size, interspecies H2 transfer and specific regulatory phenomena, the accumulation of cellobiose and acetate.

Process for preparing multilayer enzyme coating on a fiber

DOEpatents

Kim, Jungbae [Richland, WA; Kwak, Ja Hun [Richland, WA; Grate, Jay W [West Richland, WA

2009-11-03

A process for preparing high stability, high activity biocatalytic materials is disclosed and processes for using the same. The process involves coating of a material or fiber with enzymes and enzyme aggregate providing a material or fiber with high biocatalytic activity and stability useful in heterogeneous environments. In one illustrative approach, enzyme "seeds" are covalently attached to polymer nanofibers followed by treatment with a reagent that crosslinks additional enzyme molecules to the seed enzymes forming enzyme aggregates thereby improving biocatalytic activity due to increased enzyme loading and enzyme stability. This approach creates a useful new biocatalytic immobilized enzyme system with potential applications in bioconversion, bioremediation, biosensors, and biofuel cells.

Advanced modelling, monitoring, and process control of bioconversion systems

NASA Astrophysics Data System (ADS)

Schmitt, Elliott C.

Production of fuels and chemicals from lignocellulosic biomass is an increasingly important area of research and industrialization throughout the world. In order to be competitive with fossil-based fuels and chemicals, maintaining cost-effectiveness is critical. Advanced process control (APC) and optimization methods could significantly reduce operating costs in the biorefining industry. Two reasons APC has previously proven challenging to implement for bioprocesses include: lack of suitable online sensor technology of key system components, and strongly nonlinear first principal models required to predict bioconversion behavior. To overcome these challenges batch fermentations with the acetogen Moorella thermoacetica were monitored with Raman spectroscopy for the conversion of real lignocellulosic hydrolysates and a kinetic model for the conversion of synthetic sugars was developed. Raman spectroscopy was shown to be effective in monitoring the fermentation of sugarcane bagasse and sugarcane straw hydrolysate, where univariate models predicted acetate concentrations with a root mean square error of prediction (RMSEP) of 1.9 and 1.0 g L-1 for bagasse and straw, respectively. Multivariate partial least squares (PLS) models were employed to predict acetate, xylose, glucose, and total sugar concentrations for both hydrolysate fermentations. The PLS models were more robust than univariate models, and yielded a percent error of approximately 5% for both sugarcane bagasse and sugarcane straw. In addition, a screening technique was discussed for improving Raman spectra of hydrolysate samples prior to collecting fermentation data. Furthermore, a mechanistic model was developed to predict batch fermentation of synthetic glucose, xylose, and a mixture of the two sugars to acetate. The models accurately described the bioconversion process with an RMSEP of approximately 1 g L-1 for each model and provided insights into how kinetic parameters changed during dual substrate fermentation with diauxic growth. Model predictive control (MPC), an advanced process control strategy, is capable of utilizing nonlinear models and sensor feedback to provide optimal input while ensuring critical process constraints are met. Using the microorganism Saccharomyces cerevisiae, a commonly used microorganism for biofuel production, and work performed with M. thermoacetica, a nonlinear MPC was implemented on a continuous membrane cell-recycle bioreactor (MCRB) for the conversion of glucose to ethanol. The dilution rate was used to control the ethanol productivity of the system will maintaining total substrate conversion above the constraint of 98%. PLS multivariate models for glucose (RMSEP 1.5 g L-1) and ethanol (RMSEP 0.4 g L-1) were robust in predicting concentrations and a mechanistic kinetic model built accurately predicted continuous fermentation behavior. A setpoint trajectory, ranging from 2 - 4.5 g L-1 h-1 for productivity was closely tracked by the fermentation system using Raman measurements and an extended Kalman filter to estimate biomass concentrations. Overall, this work was able to demonstrate an effective approach for real-time monitoring and control of a complex fermentation system.

The Impact of Enzyme Characteristics on Corn Stover Fiber Degradation and Acid Production During Ensiled Storage

NASA Astrophysics Data System (ADS)

Ren, Haiyu; Richard, Tom L.; Moore, Kenneth J.

Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commerical enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C ∶ H). The highest C ∶ H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.

Complete genome sequence of 'Mycobacterium neoaurum' NRRL B-3805, an androstenedione (AD) producer for industrial biotransformation of sterols.

PubMed

Rodríguez-García, Antonio; Fernández-Alegre, Estela; Morales, Alejandro; Sola-Landa, Alberto; Lorraine, Jess; Macdonald, Sandy; Dovbnya, Dmitry; Smith, Margaret C M; Donova, Marina; Barreiro, Carlos

2016-04-20

Microbial bioconversion of sterols into high value steroid precursors, such as 4-androstene-3,17-dione (AD), is an industrial challenge. Genes and enzymes involved in sterol degradation have been proposed, although the complete pathway is not yet known. The genome sequencing of the AD producer strain 'Mycobacterium neoaurum' NRRL B-3805 (formerly Mycobacterium sp. NRRL B-3805) will serve to elucidate the critical steps for industrial processes and will provide the basis for further genetic engineering. The genome comprises a circular chromosome (5 421 338bp), is devoid of plasmids and contains 4844 protein-coding genes. Copyright © 2016 Elsevier B.V. All rights reserved.

A Review on The Bioconversion of Lignin to Microbial Lipid with Oleaginous Rhodococcus opacus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahan, Kristina M.; Le, Rosemary K.; Yuan, Joshua

Rhodococcus opacus produces intracellular lipids from the biodegradation of lignocellulosic biomass. These lipids can be used to produce biofuels that could potentially replace petroleum-derived chemicals. Some current studies are focusing on deconstructing lignin through efficient and cost-effective pretreatment methods and improving microbial lipid titers. Furthermore, R. opacus can reach high levels of oleaginicity (>80%) when grown on glucose and other aromatic model compounds but intracellular lipid production is much lower on complex recalcitrant lignin substrates. Our review will discuss recent advances in studying R. opacus lignin degradation by exploring different pretreatment methods, increasing lignin solubility, enriching for low molecular weightmore » lignin compounds and laccase supplementation.« less

Bioconversion of oil sludge into biomass of lipid metabolites for use as a source of biofuel

NASA Astrophysics Data System (ADS)

Shchemelinina, T. N.; Matistov, N. V.; Markarova, M. Yu; Anchugova, E. M.

2018-01-01

The possibilities for the generation of biofuel from the results of the accumulation of lipids in oil-contaminated environments were studied. This type of accumulation occurs in the biomass of yeast strains Rhodotorula sp. VKM Y-2993D; in bacteria like Pseudomonas libanensis B-3041D and in consortia of microalgal strains such as Acutodesmus obliquus Syko-A Ch-055-12, Chlorella sp. SYKO A Ch-011-10, Monoraphidium sp., and Anabaena sp. The most promising of these for processing petroleum hydrocarbons into biofuels was found to be the consortium of microalgal strains, the content of palmitic acid of which reached 49.0 %, thereby achieving a mid-range cetane number.

Biosolubilization of coal by Candida in glucose limited cultures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitter, J.; Guillory, L.; Bose, N.K.

1990-01-01

Coal biodegradation is attracting the attention of many workers because of its significance for efficient bioconversion of coal into useful chemicals. The authors work is based upon the beneficiation of a fungus (candida) on subbituminous coal. Candida was grown on both solid and liquid sabouraud medium and the coal solubilizing activity was studied at varying glucose concentration and temperature. Lower glucose concentration and higher temperature enhanced coal solubilizing activity by this fungus. Preliminary work has begun on analyzing organic extractions (alumina chromatography) of the liquid produced after microbial solubilization, including elemental analysis, solubility, molecular weights and chemical structure. This preliminarymore » work suggests that the candida could metabolize naturally occurring coal as substrate.« less

A Review on The Bioconversion of Lignin to Microbial Lipid with Oleaginous Rhodococcus opacus

DOE PAGES

Mahan, Kristina M.; Le, Rosemary K.; Yuan, Joshua; ...

2017-06-29

Rhodococcus opacus produces intracellular lipids from the biodegradation of lignocellulosic biomass. These lipids can be used to produce biofuels that could potentially replace petroleum-derived chemicals. Some current studies are focusing on deconstructing lignin through efficient and cost-effective pretreatment methods and improving microbial lipid titers. Furthermore, R. opacus can reach high levels of oleaginicity (>80%) when grown on glucose and other aromatic model compounds but intracellular lipid production is much lower on complex recalcitrant lignin substrates. Our review will discuss recent advances in studying R. opacus lignin degradation by exploring different pretreatment methods, increasing lignin solubility, enriching for low molecular weightmore » lignin compounds and laccase supplementation.« less

Bioconversion of Xylan to triglycerides by oil-rich yeasts. [Cryptococcus albidus; Cryptococcus terricoluus; Trichosporon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fall, R.; Phelps, P.; Spindler, D.

A series of lipid-accumulating yeasts was examined for their potential to saccharify xylan and accumulate triglyceride. Of the genera tested, including Candida, Cryptococcus, Lipomyces, Rhodosporidium, Rhodotorula, and Trichosporon, only Crytococcus and Trichosporon isolates saccharified xylan. All of the strains could assimilate xylose and accumuate triglyceride under nitrogen-limiting conditions. Strains of Cryptococcus albidus were found to be especially useful for a one-step saccharification of xylan coupled to triglyceride synthesis. Crytococcus terricolus, a strain constitutive for lipid accumulation, lacked extracellular xylanase, but did assimilate xylose and xylobiose and was able to continuously convert xylan to triglyceride if the culture medium was supplementedmore » with xylanase. 22 references.« less

Solar Energy: Its Technologies and Applications

DOE R&D Accomplishments Database

Auh, P. C.

1978-06-01

Solar heat, as a potential source of clean energy, is available to all of us. Extensive R and D efforts are being made to effectively utilize this renewable energy source. A variety of different technologies for utilizing solar energy have been proven to be technically feasible. Here, some of the most promising technologies and their applications are briefly described. These are: Solar Heating and Cooling of Buildings (SHACOB), Solar Thermal Energy Conversion (STC), Wind Energy Conversion (WECS), Bioconversion to Fuels (BCF), Ocean Thermal Energy Conversion (OTEC), and Photovoltaic Electric Power Systems (PEPS). Special emphasis is placed on the discussion of the SHACOB technologies, since the technologies are being expeditiously developed for the near commercialization.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1999-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Quang A.

1998-01-01

An apparatus for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards of downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets.

Steroid biotransformations in biphasic systems with Yarrowia lipolytica expressing human liver cytochrome P450 genes

PubMed Central

2012-01-01

Background Yarrowia lipolytica efficiently metabolizes and assimilates hydrophobic compounds such as n-alkanes and fatty acids. Efficient substrate uptake is enabled by naturally secreted emulsifiers and a modified cell surface hydrophobicity and protrusions formed by this yeast. We were examining the potential of recombinant Y. lipolytica as a biocatalyst for the oxidation of hardly soluble hydrophobic steroids. Furthermore, two-liquid biphasic culture systems were evaluated to increase substrate availability. While cells, together with water soluble nutrients, are maintained in the aqueous phase, substrates and most of the products are contained in a second water-immiscible organic solvent phase. Results For the first time we have co-expressed the human cytochromes P450 2D6 and 3A4 genes in Y. lipolytica together with human cytochrome P450 reductase (hCPR) or Y. lipolytica cytochrome P450 reductase (YlCPR). These whole-cell biocatalysts were used for the conversion of poorly soluble steroids in biphasic systems. Employing a biphasic system with the organic solvent and Y. lipolytica carbon source ethyl oleate for the whole-cell bioconversion of progesterone, the initial specific hydroxylation rate in a 1.5 L stirred tank bioreactor was further increased 2-fold. Furthermore, the product formation was significantly prolonged as compared to the aqueous system. Co-expression of the human CPR gene led to a 4-10-fold higher specific activity, compared to the co-overexpression of the native Y. lipolytica CPR gene. Multicopy transformants showed a 50-70-fold increase of activity as compared to single copy strains. Conclusions Alkane-assimilating yeast Y. lipolytica, coupled with the described expression strategies, demonstrated its high potential for biotransformations of hydrophobic substrates in two-liquid biphasic systems. Especially organic solvents which can be efficiently taken up and/or metabolized by the cell might enable more efficient bioconversion as compared to aqueous systems and even enable simple, continuous or at least high yield long time processes. PMID:22876969

Contributions of a unique β-clamp to substrate recognition illuminates the molecular basis of exolysis in ferulic acid esterases.

PubMed

Gruninger, Robert J; Cote, Chris; McAllister, Tim A; Abbott, D Wade

2016-04-01

Lignocellulosic biomass is a promising renewable resource; however, deconstruction of this material is still the rate-limiting step. Major obstacles in the biocatalytic turnover of lignocellulose are ester-linked decorations that prevent access to primary structural polysaccharides. Enzymes targeting these esters represent promising biotools for increasing bioconversion efficiency. Ruminant livestock are unique in their ability to degrade lignocellulose through the action of their gut microbiome. The anaerobic fungi (phylum Neocallimastigomycota) are key members of this ecosystem that express a large repertoire of carbohydrate-active enzymes (CAZymes) with little sequence identity with characterized CAZymes [Lombard, Golaconda, Drula, Coutinho and Henrissat (2014) Nucleic Acids Res. 42: , D490-D495]. We have identified a carbohydrate esterase family 1 (CE1) ferulic acid esterase (FAE) belonging to Anaeromyces mucronatus(AmCE1/Fae1a), and determined its X-ray structure in both the presence [1.55 Å (1 Å=0.1 nm)] and absence (1.60 Å) of ferulic acid. AmCE1 adopts an α/β-hydrolase fold that is structurally conserved with bacterial FAEs, and possesses a unique loop, termed the β-clamp, that encloses the ligand. Isothermal titration calorimetry reveals that substrate binding is driven by enthalpic contributions, which overcomes a large entropic penalty. A comparative analysis of AmCE1 with related enzymes has uncovered the apparent structural basis for differential FAE activities targeting cross-linking ferulic acid conjugates compared with terminal decorations. Based on comparisons to structurally characterized FAEs, we propose that the β-clamp may define the structural basis of exolytic activities in FAEs. This provides a structure-based tool for predicting exolysis and endolysis in CE1. These insights hold promise for rationally identifying enzymes tailored for bioconversion of biomass with variations in cell wall composition. © 2016 Authors; published by Portland Press Limited.

Bacterial communities and metabolic activity of faecal cultures from equol producer and non-producer menopausal women under treatment with soy isoflavones.

PubMed

Guadamuro, Lucía; Dohrmann, Anja B; Tebbe, Christoph C; Mayo, Baltasar; Delgado, Susana

2017-04-17

Isoflavones are polyphenols with estrogenic activity found mainly in soy and soy-derived products that need to be metabolised in the intestine by the gut bacteria to be fully active. There is little knowledge about isoflavone bioconversion and equol production in the human intestine. In this work, we developed an in vitro anaerobic culture model based on faecal slurries to assess the impact of isoflavone supplementation on the overall intestinal bacterial composition changes and associated metabolic transformations. In the faecal anaerobic batch cultures of this study bioconversion of isoflavones into equol was possible, suggesting the presence of viable equol-producing bacterial taxa within the faeces of menopausal women with an equol producer phenotype. The application of high-throughput DNA sequencing of 16S rRNA gene amplicons revealed the composition of the faecal cultures to be modified by the addition of isoflavones, with enrichment of some bacterial gut members associated with the metabolism of phenolics and/or equol production, such as Collinsella, Faecalibacterium and members of the Clostridium clusters IV and XIVa. In addition, the concentration of short-chain fatty acids (SCFAs) detected in the isoflavone-containing faecal cultures was higher in those inoculated with faecal slurries from equol-producing women. This study constitutes the first step in the development of a faecal culturing system with isoflavones that would further allow the selection and isolation of intestinal bacterial types able to metabolize these compounds and produce equol in vitro. Although limited by the low number of faecal cultures analysed and the inter-individual bacterial diversity, the in vitro results obtained in this work tend to indicate that soy isoflavones might provide an alternative energy source for the increase of equol-producing taxa and enhancement of SCFAs production. SCFAs and equol are both considered pivotal bacterial metabolites in the triggering of intestinal health-related beneficial effects.

Microbial community structures in high rate algae ponds for bioconversion of agricultural wastes from livestock industry for feed production.

PubMed

Mark Ibekwe, A; Murinda, Shelton E; Murry, Marcia A; Schwartz, Gregory; Lundquist, Trygve

2017-02-15

Dynamics of seasonal microbial community compositions in algae cultivation ponds are complex. However, there is very limited knowledge on bacterial communities that may play significant roles with algae in the bioconversion of manure nutrients to animal feed. In this study, water samples were collected during winter, spring, summer, and fall from the dairy lagoon effluent (DLE), high rate algae ponds (HRAP) that were fed with diluted DLE, and municipal waste water treatment plant (WWTP) effluent which was included as a comparison system for the analysis of total bacteria, Cyanobacteria, and microalgae communities using MiSeq Illumina sequencing targeting the 16S V4 rDNA region. The main objective was to examine dynamics in microbial community composition in the HRAP used for the production of algal biomass. DNA was extracted from the different sample types using three commercially available DNA extraction kits; MoBio Power water extraction kit, Zymo fungi/bacterial extraction kit, and MP Biomedicals FastDNA SPIN Kit. Permutational analysis of variance (PERMANOVA) using distance matrices on each variable showed significant differences (P=0.001) in beta-diversity based on sample source. Environmental variables such as hydraulic retention time (HRT; P<0.031), total N (P<0.002), total inorganic N (P<0.002), total P (P<0.002), alkalinity (P<0.002), pH (P<0.022), total suspended solid (TSS; P<0.003), and volatile suspended solids (VSS; P<0.002) significantly affected microbial communities in DLE, HRAP, and WWTP. Of the operational taxonomic units (OTUs) identified to phyla level, the dominant classes of bacteria identified were: Cyanobacteria, Alpha-, Beta-, Gamma-, Epsilon-, and Delta-proteobacteria, Bacteroidetes, Firmicutes, and Planctomycetes. Our data suggest that microbial communities were significantly affected in HRAP by different environmental variables, and care must be taken in extraction procedures when evaluating specific groups of microbial communities for specific functions. Published by Elsevier B.V.

Metabolism and Fatty Acid Profile in Fat and Lean Rainbow Trout Lines Fed with Vegetable Oil: Effect of Carbohydrates

PubMed Central

Kamalam, Biju Sam; Médale, Françoise; Larroquet, Laurence; Corraze, Geneviève; Panserat, Stephane

2013-01-01

The present study investigated the effect of dietary carbohydrates on metabolism, with special focus on fatty acid bioconversion and flesh lipid composition in two rainbow trout lines divergently selected for muscle lipid content and fed with vegetable oils. These lines were chosen based on previously demonstrated potential differences in LC-PUFA synthesis and carbohydrate utilization. Applying a factorial study design, juvenile trout from the lean (L) and the fat (F) line were fed vegetable oil based diets with or without gelatinised starch (17.1%) for 12 weeks. Blood, liver, muscle, intestine and adipose tissue were sampled after the last meal. Feed intake and growth was higher in the L line than the F line, irrespective of the diet. Moderate postprandial hyperglycemia, strong induction of hepatic glucokinase and repressed glucose-6-phosphatase transcripts confirmed the metabolic response of both lines to carbohydrate intake. Further at the transcriptional level, dietary carbohydrate in the presence of n-3 LC-PUFA deficient vegetable oils enhanced intestinal chylomicron assembly, disturbed hepatic lipid metabolism and importantly elicited a higher response of key desaturase and elongase enzymes in the liver and intestine that endorsed our hypothesis. PPARγ was identified as the factor mediating this dietary regulation of fatty acid bioconversion enzymes in the liver. However, these molecular changes were not sufficient to modify the fatty acid composition of muscle or liver. Concerning the genotype effect, there was no evidence of substantial genotypic difference in lipid metabolism, LC-PUFA synthesis and flesh fatty acid profile when fed with vegetable oils. The minor reduction in plasma glucose and triglyceride levels in the F line was linked to potentially higher glucose and lipid uptake in the muscle. Overall, these data emphasize the importance of dietary macro-nutrient interface in evolving fish nutrition strategies. PMID:24124573

Metabolism and fatty acid profile in fat and lean rainbow trout lines fed with vegetable oil: effect of carbohydrates.

PubMed

Kamalam, Biju Sam; Médale, Françoise; Larroquet, Laurence; Corraze, Geneviève; Panserat, Stephane

2013-01-01

The present study investigated the effect of dietary carbohydrates on metabolism, with special focus on fatty acid bioconversion and flesh lipid composition in two rainbow trout lines divergently selected for muscle lipid content and fed with vegetable oils. These lines were chosen based on previously demonstrated potential differences in LC-PUFA synthesis and carbohydrate utilization. Applying a factorial study design, juvenile trout from the lean (L) and the fat (F) line were fed vegetable oil based diets with or without gelatinised starch (17.1%) for 12 weeks. Blood, liver, muscle, intestine and adipose tissue were sampled after the last meal. Feed intake and growth was higher in the L line than the F line, irrespective of the diet. Moderate postprandial hyperglycemia, strong induction of hepatic glucokinase and repressed glucose-6-phosphatase transcripts confirmed the metabolic response of both lines to carbohydrate intake. Further at the transcriptional level, dietary carbohydrate in the presence of n-3 LC-PUFA deficient vegetable oils enhanced intestinal chylomicron assembly, disturbed hepatic lipid metabolism and importantly elicited a higher response of key desaturase and elongase enzymes in the liver and intestine that endorsed our hypothesis. PPARγ was identified as the factor mediating this dietary regulation of fatty acid bioconversion enzymes in the liver. However, these molecular changes were not sufficient to modify the fatty acid composition of muscle or liver. Concerning the genotype effect, there was no evidence of substantial genotypic difference in lipid metabolism, LC-PUFA synthesis and flesh fatty acid profile when fed with vegetable oils. The minor reduction in plasma glucose and triglyceride levels in the F line was linked to potentially higher glucose and lipid uptake in the muscle. Overall, these data emphasize the importance of dietary macro-nutrient interface in evolving fish nutrition strategies.

Comparative biochemical analysis after steam pretreatment of lignocellulosic agricultural waste biomass from Williams Cavendish banana plant (Triploid Musa AAA group).

PubMed

Kamdem, Irénée; Jacquet, Nicolas; Tiappi, Florian Mathias; Hiligsmann, Serge; Vanderghem, Caroline; Richel, Aurore; Jacques, Philippe; Thonart, Philippe

2015-11-01

The accessibility of fermentable substrates to enzymes is a limiting factor for the efficient bioconversion of agricultural wastes in the context of sustainable development. This paper presents the results of a biochemical analysis performed on six combined morphological parts of Williams Cavendish Lignocellulosic Biomass (WCLB) after steam cracking (SC) and steam explosion (SE) pretreatments. Solid (S) and liquid (L) fractions (Fs) obtained from SC pretreatment performed at 180°C (SLFSC180) and 210°C (SLFSC210) generated, after diluted acid hydrolysis, the highest proportions of neutral sugar (NS) contents, specifically 52.82 ± 3.51 and 49.78 ± 1.39%w/w WCLB dry matter (DM), respectively. The highest proportions of glucose were found in SFSC210 (53.56 ± 1.33%w/w DM) and SFSC180 (44.47 ± 0.00%w/w DM), while the lowest was found in unpretreated WCLB (22.70 ± 0.71%w/w DM). Total NS content assessed in each LF immediately after SC and SE pretreatments was less than 2%w/w of the LF DM, thus revealing minor acid autohydrolysis consequently leading to minor NS production during the steam pretreatment. WCLB subjected to SC at 210 °C (SC210) generated up to 2.7-fold bioaccessible glucan and xylan. SC and SE pretreatments showed potential for the deconstruction of WCLB (delignification, depolymerization, decrystallization and deacetylation), enhancing its enzymatic hydrolysis. The concentrations of enzymatic inhibitors, such as 2-furfuraldehyde and 5-(hydroxymethyl)furfural from LFSC210, were the highest (41 and 21 µg ml(-1), respectively). This study shows that steam pretreatments in general and SC210 in particular are required for efficient bioconversion of WCLB. Yet, biotransformation through biochemical processes (e.g., anaerobic digestion) must be performed to assess the efficiency of these pretreatments. © The Author(s) 2015.

Enhanced synthesis of L-threo-3,4-dihydroxyphenylserine by high-density whole-cell biocatalyst of recombinant L-threonine aldolase from Streptomyces avelmitilis.

PubMed

Baik, Sang-Ho; Yoshioka, Hideki

2009-03-01

L-threo-3,4-Dihydroxyphenylserine (DOPS) is a chiral unnatural beta-hydroxy amino acid used for the treatment of Parkinson disease. We developed a continuous bioconversion system for DOPS production that uses whole-cell biocatalyst of recombinant Escherichia coli expressing L-threonine aldolase (L-TA) genes cloned from Streptomyces avelmitilis MA-4680. Maximum conversion rates were observed at 2 M glycine, 145 mM 3,4-dihydroxybenzaldehyde, 0.75% Triton-X, 5 g E. coli cells/l, pH 6.5 and 10 degrees C. In the optimized condition, overall productivity was 8 g/l, which represents 40 times the synthesis yield possible with no optimization of conditions.

Platform construction of molecular breeding for utilization of brown macroalgae.

PubMed

Takagi, Toshiyuki; Kuroda, Kouichi; Ueda, Mitsuyoshi

2018-01-01

Brown macroalgae are characterized by a large size and high productivity without requiring arable land, fresh water, and fertilizer. Furthermore, since brown macroalgae contain little or no lignin, simple biorefinery processing can efficiently produce sugars from this material. Therefore, brown macroalgae have attracted attention as an alternative feedstock for bioethanol production. However, the utilization of biotechnologies previously developed for terrestrial biomass processing results in difficulties in the bioconversion of brown macroalgae. Recently, several studies have developed biotechnologies for using major carbohydrates of brown macroalgae, such as laminarin, mannitol, and alginate. This review focuses on these fermentation biotechnologies using natural or engineered microorganisms. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Intra- and Extra-cellular Proteome Analyses of Steroid-Producer Mycobacteria.

PubMed

Barreiro, Carlos; Morales, Alejandro; Vázquez-Iglesias, Inés; Sola-Landa, Alberto

2017-01-01

The importance of the pathogenic mycobacteria has mainly focused the omic analyses on different aspects of their clinical significance. In contrast, those industrially relevant mycobacteria have received less attention, even though the steroids market sales in 2011, in example, were estimated in $8 billion.The extra-cellular proteome, due to its relevance in the sterols processing and uptake; as well as the intra-cellular proteome, because of its role in steroids bioconversion, are the core of the present chapter. As a proof of concept, the obtaining methods for both sub-proteomes of Mycobacterium neoaurum NRRL B-3805, a relevant industrial strain involved in steroids production, have been developed. Thus, procedures and relevant key points of these proteomes analyses are fully described.

Mulberry anthocyanin biotransformation by intestinal probiotics.

PubMed

Cheng, Jing-Rong; Liu, Xue-Ming; Chen, Zhi-Yi; Zhang, You-Sheng; Zhang, Ye-Hui

2016-12-15

This study was designed to evaluate mulberry anthocyanins bioconversion traits for intestinal probiotics. Five intestinal beneficial bacteria were incubated with mulberry anthocyanins under anaerobic conditions at 37°C, and bacterial β-glucosidase activity and anthocyanin level were determined. Results demonstrated that all strains could convert mulberry anthocyanins to some extent. With high β-glucosidase production capacity, Streptococcus thermophiles GIM 1.321 and Lactobacillus plantarum GIM 1.35 degraded mulberry anthocyanins by 46.17% and 43.62%, respectively. Mulberry anthocyanins were mainly biotransformed to chlorogenic acid, crypto-chlorogenic acid, caffeic acid, and ferulic acid during the anaerobic process. Non-enzymatic deglycosylation of anthocyanins also occurred and approximately 19.42% of the anthocyanins were degraded within 48h by this method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Application of rumen microorganisms for anaerobic bioconversion of lignocellulosic biomass.

PubMed

Yue, Zheng-Bo; Li, Wen-Wei; Yu, Han-Qing

2013-01-01

Rumen in the mammalian animals is a natural cellulose-degrading system and the microorganisms inside have been found to be able to effectively digest lignocellulosic biomass. Furthermore, methane or volatile fatty acids, which could be further converted to other biofuels, are the two major products in such a system. This paper offers an overview of recent development in the application of rumen microorganisms for lignocellulosic biomass conversion. Application of recent molecular tools in the analysis of rumen microbial community, progress in the development of artificial rumen reactors, the latest research results about characterizing rumen-dominated anaerobic digestion process and energy products are summarized. Also, the potential application of such a rumen-dominated process is discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biotransformation of artemisinin using cell suspension cultures of Catharanthus roseus (L.) G.Don and Lavandula officinalis L.

PubMed

Patel, Suman; Gaur, Rashmi; Verma, Priyanka; Bhakuni, Rajendra S; Mathur, Archana

2010-08-01

Artemisinin, an antimalarial compound, at 5 mg/40 ml, was transformed by cell suspension cultures of Catharanthus roseus (L.) G.Don and Lavandula officinalis L. into deoxyartemisinin with yields >78% (3.93 mg deoxyartemisinin from 5 mg artemisinin). Maximum conversion (78.6 and 78%) occurred after 6 and 7 days of adding artemisinin to 20 and 9 days old cultures of C. roseus and L. officinalis, respectively. The procedure was scaled up by and 500 mg artemisinin was transformed into 390 mg deoxyartemisinin. Addition of artemisinin at the beginning of the culture cycle resulted in >50% reduction in dry biomass production with no bioconversion. Conversion of artemisinin occurred intracellularly followed by leaching of the product into the medium.

Engineering the robustness of industrial microbes through synthetic biology.

PubMed

Zhu, Linjiang; Zhu, Yan; Zhang, Yanping; Li, Yin

2012-02-01

Microbial fermentations and bioconversions play a central role in the production of pharmaceuticals, enzymes and chemicals. To meet the demands of industrial production, it is desirable that microbes maintain a maximized carbon flux towards target metabolites regardless of fluctuations in intracellular or extracellular environments. This requires cellular systems that maintain functional stability and dynamic homeostasis in a given physiological state, or manipulate transitions between different physiological states. Stable maintenance or smooth transition can be achieved through engineering of dynamic controllability, modular and hierarchical organization, or functional redundancy, three key features of biological robustness in a cellular system. This review summarizes how synthetic biology can be used to improve the robustness of industrial microbes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1998-03-31

An apparatus is disclosed for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material. The apparatus consists of a tower bioreactor which has mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

Tower reactors for bioconversion of lignocellulosic material

DOEpatents

Nguyen, Q.A.

1999-03-30

An apparatus is described for enzymatic hydrolysis and fermentation of pretreated lignocellulosic material, in the form of a tower bioreactor, having mixers to achieve intermittent mixing of the material. Precise mixing of the material is important for effective heat and mass transfer requirements without damaging or denaturing the enzymes or fermenting microorganisms. The pretreated material, generally in the form of a slurry, is pumped through the bioreactor, either upwards or downwards, and is mixed periodically as it passes through the mixing zones where the mixers are located. For a thin slurry, alternate mixing can be achieved by a pumping loop which also serves as a heat transfer device. Additional heat transfer takes place through the reactor heat transfer jackets. 5 figs.

One-pot bioconversion of algae biomass into terpenes for advanced biofuels and bioproducts

DOE PAGES

Davis, Ryan Wesley; Wu, Weihua

2016-01-01

In this study, rising demand for transportation fuels, diminishing reserved of fossil oil, and the concerns with fossil fuel derived environmental pollution as well as the green-house gas emission derived climate change have resulted in the compelling need for alternative, sustainable new energy sources(1). Algae-based biofuels have been considered one of the promising alternatives to fossil fuels as they can overcome some of these issues (2-4). The current state-of-art of algal biofuel technologies have primarily focused on biodiesel production through prompting high algal lipid yields under the nutrient stress conditions. There are less interests of using algae-based carbohydrate and proteinsmore » as carbon sources for the fermentative production of liquid fuel compounds or other high-value bioproducts(5-7).« less

Modeling of anaerobic degradation of solid slaughterhouse waste: inhibition effects of long-chain fatty acids or ammonia.

PubMed

Lokshina, L Y; Vavilin, V A; Salminen, E; Rintala, J

2003-01-01

The anaerobic bioconversion of solid poultry slaughterhouse wastes was kinetically investigated. The modified version of simulation model was applied for description of experimental data in mesophilic laboratory digester and assays. Additionally, stages of formation and consumption of long chain fatty acids (LCFA) were included in the model. Batch data on volatile solids, ammonium, acetate, butyrate, propionate, LCFA concentrations, pH level, cumulative volume, and methane partial pressure were used for model calibration. As a reference, the model was used to describe digestion of solid sorted household waste. Simulation results showed that an inhibition of polymer hydrolysis by volatile fatty acids and acetogenesis by NH3 or LCFA could be responsible for the complex system dynamics during degradation of lipid- and protein-rich wastes.

An engineered microbial platform for direct biofuel production from brown macroalgae.

PubMed

Wargacki, Adam J; Leonard, Effendi; Win, Maung Nyan; Regitsky, Drew D; Santos, Christine Nicole S; Kim, Peter B; Cooper, Susan R; Raisner, Ryan M; Herman, Asael; Sivitz, Alicia B; Lakshmanaswamy, Arun; Kashiyama, Yuki; Baker, David; Yoshikuni, Yasuo

2012-01-20

Prospecting macroalgae (seaweeds) as feedstocks for bioconversion into biofuels and commodity chemical compounds is limited primarily by the availability of tractable microorganisms that can metabolize alginate polysaccharides. Here, we present the discovery of a 36-kilo-base pair DNA fragment from Vibrio splendidus encoding enzymes for alginate transport and metabolism. The genomic integration of this ensemble, together with an engineered system for extracellular alginate depolymerization, generated a microbial platform that can simultaneously degrade, uptake, and metabolize alginate. When further engineered for ethanol synthesis, this platform enables bioethanol production directly from macroalgae via a consolidated process, achieving a titer of 4.7% volume/volume and a yield of 0.281 weight ethanol/weight dry macroalgae (equivalent to ~80% of the maximum theoretical yield from the sugar composition in macroalgae).

One-pot bioconversion of algae biomass into terpenes for advanced biofuels and bioproducts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Ryan Wesley; Wu, Weihua

In this study, rising demand for transportation fuels, diminishing reserved of fossil oil, and the concerns with fossil fuel derived environmental pollution as well as the green-house gas emission derived climate change have resulted in the compelling need for alternative, sustainable new energy sources(1). Algae-based biofuels have been considered one of the promising alternatives to fossil fuels as they can overcome some of these issues (2-4). The current state-of-art of algal biofuel technologies have primarily focused on biodiesel production through prompting high algal lipid yields under the nutrient stress conditions. There are less interests of using algae-based carbohydrate and proteinsmore » as carbon sources for the fermentative production of liquid fuel compounds or other high-value bioproducts(5-7).« less

Bioconversion potential of Trichoderma viride HN1 cellulase for a lignocellulosic biomass Saccharum spontaneum.

PubMed

Iqtedar, Mehwish; Nadeem, Mohammad; Naeem, Hira; Abdullah, Roheena; Naz, Shagufta; Qurat ul Ain Syed; Kaleem, Afshan

2015-01-01

The industrialisation of lignocellulose conversion is impeded by expensive cellulase enzymes required for saccharification in bioethanol production. Current research undertakes cellulase production from pretreated Saccharum spontaneum through Trichoderma viride HN1 under submerged fermentation conditions. Pretreatment of substrate with 2% NaOH resulted in 88% delignification. Maximum cellulase production (2603 ± 16.39 U/mL/min carboxymethyl cellulase and 1393 ± 25.55 U/mL/min FPase) was achieved at 6% substrate at pH 5.0, with 5% inoculum, incubated at 35°C for 120 h of fermentation period. Addition of surfactant, Tween 80 and metal ion Mn(+2), significantly enhanced cellulase yield. This study accounts proficient cellulase yield through process optimisation by exploiting cheaper substrate to escalate their commercial endeavour.

Genomic sequence of the xylose fermenting, insect-inhabitingyeast, Pichia stipitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeffries, Thomas W.; Grigoriev, Igor; Grimwood, Jane

2007-06-25

Xylose is a major constituent of angiosperm lignocellulose,so its fermentation is important for bioconversion to fuels andchemicals. Pichia stipitis is the best-studied native xylose fermentingyeast. Genes from P. stipitis have been used to engineer xylosemetabolism in Saccharomycescerevisiae, and the regulation of the P.stipitis genome offers insights into the mechanisms of xylose metabolismin yeasts. We have sequenced, assembled and finished the genome ofP.stipitis. As such, it is one of only a handful of completely finishedeukaryotic organisms undergoing analysis and manual curation. Thesequence has revealed aspects of genome organization, numerous genes forbiocoversion, preliminary insights into regulation of central metabolicpathways, numerous examples ofmore » co-localized genes with related functions,and evidence of how P. stipitis manages to achieve redox balance whilegrowing on xylose under microaerobic conditions.« less

Biocatalytic production of D-tagatose: A potential rare sugar with versatile applications.

PubMed

Jayamuthunagai, J; Gautam, P; Srisowmeya, G; Chakravarthy, M

2017-11-02

D-tagatose is a naturally existing rare monosaccharide having prebiotic properties. Minimal absorption, low metabolizing energy, and unique clinical properties are the characteristics of D-tagatose. D-tagatose gained international attention by matching the purpose of alternate sweeteners that is much needed for the control of diabetes among world population. Recent efforts in understanding tagatose bioconversion have generated essential information regarding its production and application. This article reviews the evolution of D-tagatose as an important rare sugar by appreciable improvements in production results and its significant applications resulted of its unique physical, chemical, biological, and clinical properties thus considering it an appropriate product for requisite improvements in technical viability. Based on current knowledge and technology projections, the commercialization of D-tagatose rare sugar as food additive is close to reality.

Method and apparatus for the removal of bioconversion of constituents of organic liquids

DOEpatents

Scott, Timothy; Scott, Charles D.

1994-01-01

A method and apparatus for the removal or conversion of constituents from bulk organic liquids. A countercurrent biphasic bioreactor system is utilized to disperse and recoalesce a biocatalyst contained in the aqueous liquid phase into the organic liquid phase containing the constituent. Two transient, high-intensity electrical fields rupture the aqueous drops into a plurality of microdroplets and induce continuous coalescence and redispersion as the microdroplets travel through the organic phase, thus increasing surface area. As the aqueous microdroplets progress through the organic phase, the biocatalyst then reacts with the constituent to produce a product which is then removed from the bioreactor in the aqueous phase or retained in the organic phase. The organic liquid, now free of the original constituents, is ready for immediate use or further processing.

GM biofortified crops: potential effects on targeting the micronutrient intake gap in human populations.

PubMed

De Steur, Hans; Mehta, Saurabh; Gellynck, Xavier; Finkelstein, Julia L

2017-04-01

Genetic engineering has been successfully applied to increase micronutrient content in staple crops. Nutrition evidence is key to ensure scale-up and successful implementation. Unlike conventional plant breeding efforts, research on the efficacy or effectiveness of GM biofortified crops on nutritional status in human populations is lacking. This review reports on the potential role of GM biofortified crops in closing the micronutrient gap - increasing the dietary intake of micronutrients in human populations. To date, one clinical trial in the United States reported a high bio-conversion rate of β-carotene in Golden Rice, and potential effects of GM biofortified crop consumption on dietary intake and nutritional outcomes are promising. However, further research needs to confirm the ex ante assessments in target regions. Copyright © 2017. Published by Elsevier Ltd.

Multidisciplinary research program directed toward utilization of solar energy through bioconversion of renewable resources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-07-01

Progress is reported in this multidisciplinary research program. Genetic selection of superior trees, physiological basis of vigor, tissue culture systems leading to cloning of diploid and haploid cell lines are discussed in the Program A report. The physiological basis of enhanced oleoresin formation in southern pines when treated with sublethal concentrations of the herbicide paraquat was investigated in Program B. In Program C, metabolic changes in the stems of slash pine, in vivo, after application with paraquat were determined. The use of phdoem and xylem tissue slices as a laboratory model for studying paraquat associated- and normal-terpene synthesis in pinesmore » is discussed. The biochemistry and physiology of methane formation from cellulose during anaerobic fermentation are discussed in the Program D report. (DMC)« less

Optimization and cost estimation of novel wheat biorefining for continuous production of fermentation feedstock.

PubMed

Arifeen, Najmul; Wang, Ruohang; Kookos, Ioannis; Webb, Colin; Koutinas, Apostolis A

2007-01-01

A wheat-based continuous process for the production of a nutrient-complete feedstock for bioethanol production by yeast fermentation has been cost-optimized. This process could substitute for the current wheat dry milling process employed in industry for bioethanol production. Each major wheat component (bran, gluten, starch) is extracted and processed for different end-uses. The separate stages, liquefaction and saccharification, used currently in industry for starch hydrolysis have been integrated into a simplified continuous process by exploiting the complex enzymatic consortium produced by on-site fungal bioconversions. A process producing 120 m3 h-1 nutrient-complete feedstock for bioethanol production containing 250 g L-1 glucose and 0.85 g L-1 free amino nitrogen would result in a production cost of $0.126/kg glucose.

Bioreduction of α,β-unsaturated ketones and aldehydes by non-conventional yeast (NCY) whole-cells.

PubMed

Goretti, Marta; Ponzoni, Chiara; Caselli, Elisa; Marchegiani, Elisabetta; Cramarossa, Maria Rita; Turchetti, Benedetta; Forti, Luca; Buzzini, Pietro

2011-03-01

The bioreduction of α,β-unsaturated ketones (ketoisophorone, 2-methyl- and 3-methyl-cyclopentenone) and aldehydes [(S)-(-)-perillaldehyde and α-methyl-cinnamaldehyde] by 23 "non-conventional" yeasts (NCYs) belonging to 21 species of the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma, and Wickerhamomyces was reported. The results highlight the potential of NCYs as whole-cell biocatalysts for selective biotransformation of electron-poor alkenes. A few NCYs exhibited extremely high (>90%) or even total ketoisophorone and 2-methyl-cyclopentenone bioconversion yields via asymmetric reduction of the conjugated CC bond catalyzed by enoate reductases. Catalytic efficiency declined after switching from ketones to aldehydes. High chemoselectivity due to low competing carbonyl reductases was also sometimes observed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Enhanced absorption of cyclosporin A by complexation with dimethyl-beta-cyclodextrin in bile duct-cannulated and -noncannulated rats.

PubMed

Miyake, K; Arima, H; Irie, T; Hirayama, F; Uekama, K

1999-01-01

The enhancing effects of dimethyl-beta-cyclodextrin (DM-beta-CyD) on the absorption of cyclosporin A (CsA) after oral administration to rats under bile duct-cannulated and -noncannulated conditions were investigated. The dissolution rate of CsA was markedly augmented by complexation with DM-beta-CyD. In a closed loop in situ study, DM-beta-CyD considerably increased the cumulative amounts of CsA in the mesenteric venous blood after injection of the aqueous CsA suspension into the small intestinal sac of rats. In addition, the cumulative amount ratio of M1, the dominant metabolite of CsA in rats, to CsA in the mesenteric venous blood for up to 40 min after the injection of the CsA-DM-beta-CyD suspension into the sac was lower than that of the CsA suspension alone. DM-beta-CyD inhibited the bioconversion of CsA in the small intestinal microsomes of rats. These results indicate that the bioconversion of CsA was abated by complexation with DM-beta-CyD. An in vivo study revealed that DM-beta-CyD increased the transfer of CsA to blood, not lymph, with low variability in the absorption after oral administration of the CsA suspension to rats. The variability of bioavailability of DM-beta-CyD complex was lower than that of Sandimmune, although the extent of bioavailability of DM-beta-CyD was only a little higher than that of Sandimmune. The bioavailability of CsA or its DM-beta-CyD complex was appreciably decreased by the cannulation of the bile duct of rats, and the extent of the lowering in the bioavailability in the presence of DM-beta-CyD was much less serious than that of CsA alone. The present results suggest that DM-beta-CyD is particularly useful in designing oral preparations of CsA with an enhanced bioavailability and a reduced variability in absorption.

Highly effective, regiospecific reduction of chalcone by cyanobacteria leads to the formation of dihydrochalcone: two steps towards natural sweetness.

PubMed

Żyszka, Beata; Anioł, Mirosław; Lipok, Jacek

2017-08-04

Chalcones are the biogenetic precursors of all known flavonoids, which play an essential role in various metabolic processes in photosynthesizing organisms. The use of whole cyanobacteria cells in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone, is reported. The prokaryotic microalgae cyanobacteria are known to produce phenolic compounds, including flavonoids, as natural components of cells. It seems logical that organisms producing such compounds possess a suitable "enzymatic apparatus" to carry out their biotransformation. Therefore, determination of the ability of whole cells of selected cyanobacteria to carry out biocatalytic transformations of chalcone, the biogenetic precursor of all known flavonoids, was the aim of our study. Chalcone was found to be converted to dihydrochalcone by all examined cyanobacterial strains; however, the effectiveness of this process depends on the strain with biotransformation yields ranging from 3% to >99%. The most effective biocatalysts are Anabaena laxa, Aphanizomenon klebahnii, Nodularia moravica, Synechocystis aquatilis (>99% yield) and Merismopedia glauca (92% yield). The strains Anabaena sp. and Chroococcus minutus transformed chalcone in more than one way, forming a few products; however, dihydrochalcone was the dominant product. The course of biotransformation shed light on the pathway of chalcone conversion, indicating that the process proceeds through the intermediate cis-chalcone. The scaled-up process, conducted on a preparative scale and by using a mini-pilot photobioreactor, fully confirmed the high effectiveness of this bioconversion. Moreover, in the case of the mini-pilot photobioreactor batch cultures, the optimization of culturing conditions allowed the shortening of the process conducted by A. klebahnii by 50% (from 8 to 4 days), maintaining its >99% yield. This is the first report related to the use of whole cells of halophilic and freshwater cyanobacteria strains in a two-step, light-catalysed regioselective bio-reduction of chalcone, leading to the formation of the corresponding dihydrochalcone. The total bioconversion of chalcone in analytical, preparative, and mini-pilot scales of this process creates the possibility of its use in the food industry for the production of natural sweeteners.

A Simple Plasma Retinol Isotope Ratio Method for Estimating β-Carotene Relative Bioefficacy in Humans: Validation with the Use of Model-Based Compartmental Analysis.

PubMed

Ford, Jennifer Lynn; Green, Joanne Balmer; Lietz, Georg; Oxley, Anthony; Green, Michael H

2017-09-01

Background: Provitamin A carotenoids are an important source of dietary vitamin A for many populations. Thus, accurate and simple methods for estimating carotenoid bioefficacy are needed to evaluate the vitamin A value of test solutions and plant sources. β-Carotene bioefficacy is often estimated from the ratio of the areas under plasma isotope response curves after subjects ingest labeled β-carotene and a labeled retinyl acetate reference dose [isotope reference method (IRM)], but to our knowledge, the method has not yet been evaluated for accuracy. Objectives: Our objectives were to develop and test a physiologically based compartmental model that includes both absorptive and postabsorptive β-carotene bioconversion and to use the model to evaluate the accuracy of the IRM and a simple plasma retinol isotope ratio [(RIR), labeled β-carotene-derived retinol/labeled reference-dose-derived retinol in one plasma sample] for estimating relative bioefficacy. Methods: We used model-based compartmental analysis (Simulation, Analysis and Modeling software) to develop and apply a model that provided known values for β-carotene bioefficacy. Theoretical data for 10 subjects were generated by the model and used to determine bioefficacy by RIR and IRM; predictions were compared with known values. We also applied RIR and IRM to previously published data. Results: Plasma RIR accurately predicted β-carotene relative bioefficacy at 14 d or later. IRM also accurately predicted bioefficacy by 14 d, except that, when there was substantial postabsorptive bioconversion, IRM underestimated bioefficacy. Based on our model, 1-d predictions of relative bioefficacy include absorptive plus a portion of early postabsorptive conversion. Conclusion: The plasma RIR is a simple tracer method that accurately predicts β-carotene relative bioefficacy based on analysis of one blood sample obtained at ≥14 d after co-ingestion of labeled β-carotene and retinyl acetate. The method also provides information about the contributions of absorptive and postabsorptive conversion to total bioefficacy if an additional sample is taken at 1 d. © 2017 American Society for Nutrition.

Characteristic CYP2A6 genetic polymorphisms detected by TA cloning-based sequencing in Chinese digestive system cancer patients with S-1 based chemotherapy.

PubMed

Fang, Wei-Jia; Mou, Hai-Bo; Jin, Da-Zhi; Zheng, Yu-Long; Zhao, Peng; Mao, Chen-Yu; Peng, Ling; Huang, Ming-Zhu; Xu, Nong

2012-05-01

S-1 is an oral antitumor agent that contains tegafur, which is converted to fluorouracil (5-FU) in the human body. Cytochrome P450 2A6 (CYP2A6) is the principal enzyme responsible for bioconversion of tegafur to 5-FU. A number of CYP2A6 polymorphisms have been associated with variations in enzyme activity in several ethnic populations. The CYP2A6*4C allele leads to deletion of the entire CYP2A6 gene, and is the main finding in patients with reduced CYP2A6 enzymatic activity. Thus, the aim of our study was to evaluate the allele frequencies of CYP2A6 polymorphisms in a population with cancer of the digestive system. We developed a simple screening method, which combined TA cloning and direct-sequencing, to detect CYP2A6 genetic polymorphisms in Chinese patients with cancers of the digestive system. A total of 77 patients with various types of digestive system cancers were screened for CYP2A6 genetic polymorphisms. The allele frequencies of CYP2A6*1A, CYP2A6*1B and CYP2A6*4C in the 77 patients screened were 62, 42 and 13%, respectively. Frequencies of the homozygous genotypes for CYP2A6*1A and CYP2A6*4C were 27 and 12%, respectively. As expected, patients that were determined to be homozygous for CYP2A6*4C exhibited the characteristic chemotherapy efficacy and toxicity profiles. The TA cloning-based direct sequencing method facilitated allele frequency and genotyping determination for CYP2A6*1A, 1B and 4C of cancer patients. The findings indicated that the population carries a high frequency of the CYP2A6*4C homozygous genotype. Thus, the reduced efficacy of standard chemotherapy dosage in Chinese cancer patients may be explained by the lack of CYP2A6-mediated S-1 bioconversion to 5-FU.

Key blackening and stinking pollutants in Dongsha River of Beijing: Spatial distribution and source identification.

PubMed

Song, Chen; Liu, Xiaoling; Song, Yonghui; Liu, Ruixia; Gao, Hongjie; Han, Lu; Peng, Jianfeng

2017-09-15

Elimination of black-stinking water contamination has been listed as an urgent task in the Water pollution prevention action plan promulgated by State Council of China. However, the key blackening and stinking pollutants and their sources are still unclear. In this study, water quality of a black-stinking urban river in Beijing, Dongsha River, was evaluated firstly; then the distribution of the blackening and stinking pollutants was investigated, and the key pollutants and their potential sources were identified; and finally, the health risk of those pollutants was assessed. The results showed that NH 3 N, total phosphorus, dissolved oxygen and chemical oxygen demand ranged from 1.3 to 5.3 mg/L, 0.7-3.0 mg/L, 1.0-3.2 mg/L and 29-104 mg/L, respectively. The value of TP-based trophic level index indicated that Dongsha River reached severe eutrophication level; the maximum value of chroma and odor level reached 32 and 4, respectively. The main dissolved organic compounds included aromatic protein II, soluble microbiological metabolites, fulvic acids and humic acids. The blackening pollutants Fe, Mn, Cu and S 2- were extensively detected, with significantly spatial differences along the river. Dimethyl sulfide, β-ionone, 2-methylisoborneol and geosmin were identified to be the stinking pollutants. Their concentrations covered wide ranges, and even the lowest concentration value was thousands of times higher than its olfactory threshold. Correlation analysis indicated that in the overlaying water S 2- was the key blackening pollutant, while β-ionone and geosmin were the key stinking pollutants. Principal components analysis combining with the site survey revealed their potential sources. S 2- was mainly associated with the decomposition of endogenous sulfur-containing organics; β-ionone might be generated by the endogenous β-carotene bio-conversion and the exogenous discharges, while geosmin might originate from the endogenous humus bio-conversion and anthropic wastes. Furthermore, multi-metals in the sediment posed health risks to children, while dimethyl sulfide had non-cancer health risk for adults and children. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biotechnological production of arbutins (α- and β-arbutins), skin-lightening agents, and their derivatives.

PubMed

Seo, Dong-Ho; Jung, Jong-Hyun; Lee, Jae-Eun; Jeon, Eun-Jung; Kim, Wooki; Park, Cheon-Seok

2012-09-01

Arbutins (α- and β-arbutins) are glycosylated hydroquinones that are commercially used in the cosmetic industry. These compounds have an inhibitory function against tyrosinase, a critical enzyme for generating pigments, which leads to the prevention of melanin formation, resulting in a whitening effect on the skin. Although β-arbutin is found in various plants including bearberry, wheat, and pear, α-arbutin and other arbutin derivatives are synthesized by chemical and enzymatic methods. This article presents a mini-review of recent studies on the production of α-arbutin and other α- and β-arbutin derivatives via enzymatic bioconversion methods. In addition, the structures of α- and β-arbutin derivatives and their biological activities are discussed. The catalytic characteristics of various enzymes used in the biosynthesis of arbutin derivatives are also reviewed.

Method and apparatus for the removal or bioconversion of constituents of organic liquids

DOEpatents

Scott, T.; Scott, C.D.

1994-10-25

A method and apparatus are disclosed for the removal or conversion of constituents from bulk organic liquids. A countercurrent biphasic bioreactor system is utilized to disperse and recoalesce a biocatalyst contained in the aqueous liquid phase into the organic liquid phase containing the constituent. Two transient, high-intensity electrical fields rupture the aqueous drops into a plurality of microdroplets and induce continuous coalescence and redispersion as the microdroplets travel through the organic phase, thus increasing surface area. As the aqueous microdroplets progress through the organic phase, the biocatalyst then reacts with the constituent to produce a product which is then removed from the bioreactor in the aqueous phase or retained in the organic phase. The organic liquid, now free of the original constituents, is ready for immediate use or further processing. 1 fig.

Extrusion Pretreatment of Lignocellulosic Biomass: A Review

PubMed Central

Zheng, Jun; Rehmann, Lars

2014-01-01

Bioconversion of lignocellulosic biomass to bioethanol has shown environmental, economic and energetic advantages in comparison to bioethanol produced from sugar or starch. However, the pretreatment process for increasing the enzymatic accessibility and improving the digestibility of cellulose is hindered by many physical-chemical, structural and compositional factors, which make these materials difficult to be used as feedstocks for ethanol production. A wide range of pretreatment methods has been developed to alter or remove structural and compositional impediments to (enzymatic) hydrolysis over the last few decades; however, only a few of them can be used at commercial scale due to economic feasibility. This paper will give an overview of extrusion pretreatment for bioethanol production with a special focus on twin-screw extruders. An economic assessment of this pretreatment is also discussed to determine its feasibility for future industrial cellulosic ethanol plant designs. PMID:25334065

Rearranged diterpenoids from the biotransformation of ent-trachyloban-18-oic acid by Rhizopus arrhizus.

PubMed

Leverrier, Aurélie; Martin, Marie-Thérèse; Servy, Claudine; Ouazzani, Jamal; Retailleau, Pascal; Awang, Khalijah; Mukhtar, Mat Ropi; Guéritte, Françoise; Litaudon, Marc

2010-06-25

In our search for inhibitors of the antiapoptotic protein Bcl-xL, investigation of Xylopia caudata afforded a new diterpenoid, ent-trachyloban-4beta-ol (2), and five known ent-trachylobane or ent-atisane compounds. Only ent-trachyloban-18-oic acid (1) exhibited weak binding activity to Bcl-xL. These compounds exhibited cytotoxicity against KB and HCT-116 cell lines with IC(50) values between 10 and 30 microM. Bioconversion of compound 1 by Rhizopus arrhizus afforded new hydroxylated metabolites (3-7) of the ent-trachylobane and ent-kaurene type and compound 8, with a rearranged pentacyclic carbon framework that was named rhizopene. Compounds 3-8 were noncytotoxic to the two cancer cell lines, and compounds 3 and 5 exhibited only weak binding affinity for Bcl-xL.

Value-added biotransformation of cellulosic sugars by engineered Saccharomyces cerevisiae.

PubMed

Lane, Stephan; Dong, Jia; Jin, Yong-Su

2018-07-01

The substantial research efforts into lignocellulosic biofuels have generated an abundance of valuable knowledge and technologies for metabolic engineering. In particular, these investments have led to a vast growth in proficiency of engineering the yeast Saccharomyces cerevisiae for consuming lignocellulosic sugars, enabling the simultaneous assimilation of multiple carbon sources, and producing a large variety of value-added products by introduction of heterologous metabolic pathways. While microbial conversion of cellulosic sugars into large-volume low-value biofuels is not currently economically feasible, there may still be opportunities to produce other value-added chemicals as regulation of cellulosic sugar metabolism is quite different from glucose metabolism. This review summarizes these recent advances with an emphasis on employing engineered yeast for the bioconversion of lignocellulosic sugars into a variety of non-ethanol value-added products. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dibromotyrosine and histamine derivatives from the tropical marine sponge Aplysina sp.

PubMed

Santalova, Elena A; Denisenko, Vladimir A; Stonik, Valentin A

2010-03-01

Two new compounds, 3-amino-7,8-dihydroimidazo-[1,5-c]-pyrimidin-5(6H)-one (1) and ethyl 3-(2-amino-1H-imidazol-4-yl)propylcarbamate (2), along with the previously known 7,8-dihydroimidazo-[1,5-c]-pyrimidin-5(6H)-one (3), aeroplysinin-1 (4), dibromoverongiaquinol (5), bisoxazolidinone derivative (6), aerophobins-1 (7) and -2 (8), purealidins J (9) and L, have been isolated from Aplysina sp. from the South China Sea. The structures were elucidated on the basis of 1H, 13C NMR, MS and IR analyses. The histamine-derived alkaloids 1-3 may be unknown bioconversion products of purealidin J (9), aerophobin-2 (8) and aerophobin-1 (7), respectively, when 7-9 are cleaved at C-8-C-9 in reactions of activated chemical defense in Aplysina sponge.

Production of isopropyl cis-6-hexadecenoate by regiospecific desaturation of isopropyl palmitate by a double mutant of a Rhodococcus strain.

PubMed

Koike, K; Takaiwa, M; Ara, K; Inoue, S; Kimura, Y; Ito, S

2000-02-01

Resting cells of a double mutant noted as KSM-MT66, derived from Rhodococcus sp. strain KSM-B-3 by UV irradiation, were found to cis-desaturate isopropyl hexadecanoate, yielding isopropyl cis-6-hexadecenoate. Addition of sodium glutamate (1.0%), Mg SO4 (2 mM), and thiamine (2 mM) increased the productivity of the unsaturated product in phosphate buffer. Optimal temperature and pH for the reaction were around 26 degrees C and 7, respectively. Under the optimized conditions, more than 50 g/l of isopropyl cis-6-hexadecenoate was produced after a 3-day incubation by resting cells of the mutant. Thus, cis-6-hexadecenoic acid, the main component of human sebaceous lipids, can be manufactured economically by the rhodococcal bioconversion.

Cytochrome P450 systems--biological variations of electron transport chains.

PubMed

Hannemann, Frank; Bichet, Andreas; Ewen, Kerstin M; Bernhardt, Rita

2007-03-01

Cytochromes P450 (P450) are hemoproteins encoded by a superfamily of genes nearly ubiquitously distributed in different organisms from all biological kingdoms. The reactions carried out by P450s are extremely diverse and contribute to the biotransformation of drugs, the bioconversion of xenobiotics, the bioactivation of chemical carcinogens, the biosynthesis of physiologically important compounds such as steroids, fatty acids, eicosanoids, fat-soluble vitamins and bile acids, the conversion of alkanes, terpenes and aromatic compounds as well as the degradation of herbicides and insecticides. Cytochromes P450 belong to the group of external monooxygenases and thus receive the necessary electrons for oxygen cleavage and substrate hydroxylation from different redox partners. The classical as well as the recently discovered P450 redox systems are compiled in this paper and classified according to their composition.

(-)-Epicatechin derivate from Orostachys japonicus as potential inhibitor of the human butyrylcholinesterase.

PubMed

Kim, Jang Hoon; Lee, Sang-Hyun; Lee, Hyun Woo; Sun, Ya Nan; Jang, Won-Hee; Yang, Seo-Young; Jang, Hae-Dong; Kim, Young Ho

2016-10-01

Cholinesterase inhibitors block the bioconversion of neurotransmitters by cholinesterase in the nervous system. Epicatechin derivatives (1, 3 and 5), polyphenols (6 and 7) from Orostachys japonicus, and catechin derivatives (2 and 4) from our in-house library were evaluated for their inhibitory activity on cholinesterase. Compound 5 exhibited IC50 values of 58.3±2.4 and 17.8±3.8μg/mL on AChE and BuChE, respectively. Compound 5 inhibited BuChE more strongly than AChE through a competitive behavior. In silico binding positions of 5 in the active site were predicted using Autodock 4.2 and processed in a 10000-ps molecular dynamics simulation to assess the stability of compound 5 binding. Copyright © 2016 Elsevier B.V. All rights reserved.

Potential human health effects of acid rain: report of a workshop

PubMed Central

Goyer, Robert A.; Bachmann, John; Clarkson, Thomas W.; Ferris, Benjamin G.; Graham, Judith; Mushak, Paul; Perl, Daniel P.; Rall, David P.; Schlesinger, Richard; Sharpe, William; Wood, John M.

1985-01-01

This report summarizes the potential impact of the acid precipitation phenomenon on human health. There are two major components to this phenomenon: the predepositional phase, during which there is direct human exposure to acidic substances from ambient air, and the post-depositional phase, in which the deposition of acid materials on water and soil results in the mobilization, transport, and even chemical transformation of toxic metals. Acidification increases bioconversion of mercury to methylmercury, which accumulates in fish, increasing the risk to toxicity in people who eat fish. Increase in water and soil content of lead and cadmium increases human exposure to these metals which become additive to other sources presently under regulatory control. The potential adverse health effects of increased human exposure to aluminum is not known at the present time. PMID:3896772

Use of bacterial co-cultures for the efficient production of chemicals.

PubMed

Jones, J Andrew; Wang, Xin

2017-12-02

The microbial production of chemicals has traditionally relied on a single engineered microbe to enable the complete bioconversion of substrate to final product. Recently, a growing fraction of research has transitioned towards employing a modular co-culture engineering strategy using multiple microbes growing together to facilitate a divide-and-conquer approach for chemical biosynthesis. Here, we review key success stories that leverage the unique advantages of co-culture engineering, while also addressing the critical concerns that will limit the wide-spread implementation of this technology. Future studies that address the need to monitor and control the population dynamics of each strain module, while maintaining robust flux routes towards a wide range of desired products will lead the efforts to realize the true potential of co-culture engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Succinic acid production from duckweed (Landoltia punctata) hydrolysate by batch fermentation of Actinobacillus succinogenes GXAS137.

PubMed

Shen, Naikun; Wang, Qingyan; Zhu, Jing; Qin, Yan; Liao, Siming; Li, Yi; Zhu, Qixia; Jin, Yanling; Du, Liqin; Huang, Ribo

2016-07-01

Duckweed is potentially an ideal succinic acid (SA) feedstock due to its high proportion of starch and low lignin content. Pretreatment methods, substrate content and nitrogen source were investigated to enhance the bioconversion of duckweed to SA and to reduce the costs of production. Results showed that acid hydrolysis was an effective pretreatment method because of its high SA yield. The optimum substrate concentration was 140g/L. The optimum substrate concentration was 140g/L. Corn steep liquor powder could be considered a feasible and inexpensive alternative to yeast extract as a nitrogen source. Approximately 57.85g/L of SA was produced when batch fermentation was conducted in a 1.3L stirred bioreactor. Therefore, inexpensive duckweed can be a promising feedstock for the economical and efficient production of SA through fermentation by Actinobacillus succinogenes GXAS137. Copyright © 2016. Published by Elsevier Ltd.

Biorefineries of carbon dioxide: From carbon capture and storage (CCS) to bioenergies production.

PubMed

Cheah, Wai Yan; Ling, Tau Chuan; Juan, Joon Ching; Lee, Duu-Jong; Chang, Jo-Shu; Show, Pau Loke

2016-09-01

Greenhouse gas emissions have several adverse environmental effects, like pollution and climate change. Currently applied carbon capture and storage (CCS) methods are not cost effective and have not been proven safe for long term sequestration. Another attractive approach is CO2 valorization, whereby CO2 can be captured in the form of biomass via photosynthesis and is subsequently converted into various form of bioenergy. This article summarizes the current carbon sequestration and utilization technologies, while emphasizing the value of bioconversion of CO2. In particular, CO2 sequestration by terrestrial plants, microalgae and other microorganisms are discussed. Prospects and challenges for CO2 conversion are addressed. The aim of this review is to provide comprehensive knowledge and updated information on the current advances in biological CO2 sequestration and valorization, which are essential if this approach is to achieve environmental sustainability and economic feasibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metabolic modelling in the development of cell factories by synthetic biology

PubMed Central

Jouhten, Paula

2012-01-01

Cell factories are commonly microbial organisms utilized for bioconversion of renewable resources to bulk or high value chemicals. Introduction of novel production pathways in chassis strains is the core of the development of cell factories by synthetic biology. Synthetic biology aims to create novel biological functions and systems not found in nature by combining biology with engineering. The workflow of the development of novel cell factories with synthetic biology is ideally linear which will be attainable with the quantitative engineering approach, high-quality predictive models, and libraries of well-characterized parts. Different types of metabolic models, mathematical representations of metabolism and its components, enzymes and metabolites, are useful in particular phases of the synthetic biology workflow. In this minireview, the role of metabolic modelling in synthetic biology will be discussed with a review of current status of compatible methods and models for the in silico design and quantitative evaluation of a cell factory. PMID:24688669

Comparison of Ultrasonic and CO2 Laser Pretreatment Methods on Enzyme Digestibility of Corn Stover

PubMed Central

Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

2012-01-01

To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO2 laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO2 laser irradiation. The present work demonstrated that the CO2 laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO2 laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO2 laser pretreatment on corn stover to be more effective than ultrasonic pretreatment. PMID:22605970

Comparison of ultrasonic and CO₂laser pretreatment methods on enzyme digestibility of corn stover.

PubMed

Tian, Shuang-Qi; Wang, Zhen-Yu; Fan, Zi-Luan; Zuo, Li-Li

2012-01-01

To decrease the cost of bioethanol production, biomass recalcitrance needs to be overcome so that the conversion of biomass to bioethanol becomes more efficient. CO(2) laser irradiation can disrupt the lignocellulosic physical structure and reduce the average size of fiber. Analyses with Fourier transform infrared spectroscopy, specific surface area, and the microstructure of corn stover were used to elucidate the enhancement mechanism of the pretreatment process by CO(2) laser irradiation. The present work demonstrated that the CO(2) laser had potential to enhance the bioconversion efficiency of lignocellulosic waste to renewable bioethanol. The saccharification rate of the CO(2) laser pretreatment was significantly higher than ultrasonic pretreatment, and reached 27.75% which was 1.34-fold of that of ultrasonic pretreatment. The results showed the impact of CO(2) laser pretreatment on corn stover to be more effective than ultrasonic pretreatment.

Biodiesel production by various oleaginous microorganisms from organic wastes.

PubMed

Cho, Hyun Uk; Park, Jong Moon

2018-05-01

Biodiesel is a biodegradable and renewable fuel. A large amount of research has considered microbial oil production using oleaginous microorganisms, but the commercialization of microbial lipids produced in this way remains uncertain due to the high cost of feedstock or low lipid yield. Microbial lipids can be typically produced by microalgae, yeasts, and bacteria; the lipid yields of these microorganisms can be improved by using sufficient concentrations of organic carbon sources. Therefore, combining low-cost organic compounds contained in organic wastes with cultivation of oleaginous microorganisms can be a promising approach to obtain commercial viability. However, to achieve effective bioconversion of low-cost substrates to microbial lipids, the characteristics of each microorganism and each substrate should be considered simultaneously. This article discusses recent approaches to developing cost-effective microbial lipid production processes that use various oleaginous microorganisms and organic wastes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anaerobic biotransformation of organoarsenical pesticides monomethylarsonic acid and dimethylarsinic acid

USGS Publications Warehouse

Sierra-Alvarez, R.; Yenal, U.; Feld, J.A.; Kopplin, M.; Gandolfi, A.J.; Garbarino, J.R.

2006-01-01

Monomethylarsonic acid (MMAV) and dimethylarsinic acid (DMAV) are extensively utilized as pesticides, introducing large quantities of arsenic into the environment. Once released into the environment, these organoarsenicals are subject to microbial reactions. Aerobic biodegradation of MMAV and DMAV has been evaluated, but little is known about their fate in anaerobic environments. The objective of this study was to evaluate the biotransformation of MMAV and DMAV in anaerobic sludge. Biologically mediated conversion occurred under methanogenic or sulfate-reducing conditions but not in the presence of nitrate. Monomethylarsonous acid (MMAIII) was consistently observed as an important metabolite of MMAV degradation, and it was recovered in molar yields ranging from 5 to 47%. The main biotransformation product identified from DMAV metabolism was MMAV, which was recovered in molar yields ranging from 8 to 65%. The metabolites indicate that reduction and demethylation are important steps in the anaerobic bioconversion of MMAV and DMAV, respectively. ?? 2006 American Chemical Society.

Pretreatment methods for bioethanol production.

PubMed

Xu, Zhaoyang; Huang, Fang

2014-09-01

Lignocellulosic biomass, such as wood, grass, agricultural, and forest residues, are potential resources for the production of bioethanol. The current biochemical process of converting biomass to bioethanol typically consists of three main steps: pretreatment, enzymatic hydrolysis, and fermentation. For this process, pretreatment is probably the most crucial step since it has a large impact on the efficiency of the overall bioconversion. The aim of pretreatment is to disrupt recalcitrant structures of cellulosic biomass to make cellulose more accessible to the enzymes that convert carbohydrate polymers into fermentable sugars. This paper reviews several leading acidic, neutral, and alkaline pretreatments technologies. Different pretreatment methods, including dilute acid pretreatment (DAP), steam explosion pretreatment (SEP), organosolv, liquid hot water (LHW), ammonia fiber expansion (AFEX), soaking in aqueous ammonia (SAA), sodium hydroxide/lime pretreatments, and ozonolysis are intensively introduced and discussed. In this minireview, the key points are focused on the structural changes primarily in cellulose, hemicellulose, and lignin during the above leading pretreatment technologies.

Functionalized nanocompartments (Synthosomes): limitations and prospective applications in industrial biotechnology.

PubMed

Onaca, Ozana; Nallani, Madhavan; Ihle, Saskia; Schenk, Alexander; Schwaneberg, Ulrich

2006-01-01

Synthosomes are mechanically stable vesicles with a block copolymer membrane and an engineered transmembrane protein acting as selective gate. The polymer vesicles are nanometer-sized (50-1000 nm) and functionalized by loading them with enzymes for bioconversions or encapsulating charged macromolecules for selective compound recovery/release. The Synthosome system might become a novel technology platform for biocatalysis and selective product recovery. Progress in Synthosome research comprises employed block copolymers, transmembrane channel engineering, and functionalizations, which are discussed here in detail. The challenges in transmembrane protein engineering, as well as cost-effective production, in block copolymer design and the state of the art in Synthosome characterization comprising quantification of encapsulated protein, translocation efficiency, number of transmembrane channels per vesicle, and enzyme kinetics are also presented and discussed. An assessment of the Synthosome technology platform for prospective applications in industrial (white) biotechnology concludes this review.

Study on potency of municipal solid waste conversion into renewable energy by thermal incineration and bioconversion: case study of Medan city

NASA Astrophysics Data System (ADS)

Sarah, Maya; Misran, Erni

2018-03-01

Municipal solid waste (MSW) in Medan City is facing problems either with the quantity and management of MSW. Local authority only dumped approximately 73.9% MSW in the landfill over the years. Spontaneous phenomena of methane formation in dumping site indicates the potency of MSW conversion into energy by biochemical conversion. On the contrary, the presence of plastics, woods, papers, etc. in the MSW show the potency of MSW to be treated by thermal conversion. Both thermal incineration and anaerobic digestion may convert MSW Medan City into energy. This study evaluates potency of MSW conversion into renewable energy using proximate and ultimate analysis. Overall, MSW of Medan City has the opportunities to be converted into energy by both thermal and biochemical conversion with a special requirement such as pre-dry the MSW prior incineration process and degrade organic MSW in a bioreactor.

Sustainable reduction of bioreactor contamination in an industrial fermentation pilot plant.

PubMed

Junker, Beth; Lester, Michael; Leporati, James; Schmitt, John; Kovatch, Michael; Borysewicz, Stan; Maciejak, Waldemar; Seeley, Anna; Hesse, Michelle; Connors, Neal; Brix, Thomas; Creveling, Eric; Salmon, Peter

2006-10-01

Facility experience primarily in drug-oriented fermentation equipment (producing small molecules such as secondary metabolites, bioconversions, and enzymes) and, to a lesser extent, in biologics-oriented fermentation equipment (producing large molecules such as recombinant proteins and microbial vaccines) in an industrial fermentation pilot plant over the past 15 years is described. Potential approaches for equipment design and maintenance, operational procedures, validation/verification testing, medium selection, culture purity/sterility analysis, and contamination investigation are presented, and those approaches implemented are identified. Failure data collected for pilot plant operation for nearly 15 years are presented and best practices for documentation and tracking are outlined. This analysis does not exhaustively discuss available design, operational and procedural options; rather it selectively presents what has been determined to be beneficial in an industrial pilot plant setting. Literature references have been incorporated to provide background and context where appropriate.

Clean fuels from bioconversion of solar energy. Annual report, 21 January 1980-20 January 1981

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feighner, S.D.; Sikka, H.C.

1981-03-01

The study seeks to enhance glycolic acid excretion by unicellular algae. The strains of algae selected to evaluate glycolic acid accumulation in culture medium were: Chlorella pyrenoidosa (UTEX 395), Chlamydomonas reinhardtii (UTEX 89), Scenedesmus obliquus (UTEX 393), and Ankistrodesmus braunii (UTEX 245). C. pyrenoidosa and C. reinhardtii, based on the amount of glycolic acid produced, were selected for further study. Initial experiments were conducted to measure the effect of different environmental growth conditions on the rate of glycolic accumulation in defined culture medium. The most pronounced effect on glycolic acid excretion was obtained by varying the concentration of carbon dioxidemore » in air. At 1% CO2 in air, C. pyrenoidosa accumulated 5.2 ppm glycolic acid in culture medium. Neither the pH of the culture medium nor the incubation temperature affected glycolic acid accumulation by growing C. pyrenoidosa cultures.« less

Coupling of Solar Energy to Hydrogen Peroxide Production in the Cyanobacterium Anacystis nidulans

PubMed Central

Roncel, Mercedes; Navarro, José A.; De la Rosa, Miguel A.

1989-01-01

Hydrogen peroxide production by blue-green algae (cyanobacteria) under photoautotrophic conditions is of great interest as a model system for the bioconversion of solar energy. Our experimental system was based on the photosynthetic reduction of molecular oxygen with electrons from water by Anacystis nidulans 1402-1 as the biophotocatalyst and methyl viologen as a redox intermediate. It has been demonstrated that the metabolic conditions of the algae in their different growth stages strongly influence the capacity for hydrogen peroxide photoproduction, and so the initial formation rate and net peroxide yield became maximum in the mid-log phase of growth. The overall process can be optimized in the presence of certain metabolic inhibitors such as iodoacetamide and p-hydroxymercuribenzoate, as well as by permeabilization of the cellular membrane after drastic temperature changes and by immobilization of the cells in inert supports such as agar and alginate. PMID:16347855

Interactions of a lignin-rich fraction from brewer's spent grain with gut microbiota in vitro.

PubMed

Niemi, Piritta; Aura, Anna-Marja; Maukonen, Johanna; Smeds, Annika I; Mattila, Ismo; Niemelä, Klaus; Tamminen, Tarja; Faulds, Craig B; Buchert, Johanna; Poutanen, Kaisa

2013-07-10

Lignin is a constituent of plant cell walls and thus is classified as part of dietary fiber. However, little is known about the role of lignin in gastrointestinal fermentation. In this work, a lignin-rich fraction was prepared from brewer's spent grain and subjected to an in vitro colon model to study its potential bioconversions and interactions with fecal microbiota. No suppression of microbial conversion by the fraction was observed in the colon model, as measured as short-chain fatty acid production. Furthermore, no inhibition on the growth was observed when the fraction was incubated with strains of lactobacilli and bifidobacteria. In fact, the lignin-rich fraction enabled bifidobacteria to survive longer than with glucose. Several transiently appearing phenolic compounds, very likely originating from lignin, were observed during the fermentation. This would indicate that the gut microbiota was able to partially degrade lignin and metabolize the released compounds.

Fossil energy biotechnology: A research needs assessment. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1993-11-01

The Office of Program Analysis of the US Department of Energy commissioned this study to evaluate and prioritize research needs in fossil energy biotechnology. The objectives were to identify research initiatives in biotechnology that offer timely and strategic options for the more efficient and effective uses of the Nation`s fossil resource base, particularly the early identification of new and novel applications of biotechnology for the use or conversion of domestic fossil fuels. Fossil energy biotechnology consists of a number of diverse and distinct technologies, all related by the common denominator -- biocatalysis. The expert panel organized 14 technical subjects intomore » three interrelated biotechnology programs: (1) upgrading the fuel value of fossil fuels; (2) bioconversion of fossil feedstocks and refined products to added value chemicals; and, (3) the development of environmental management strategies to minimize and mitigate the release of toxic and hazardous petrochemical wastes.« less

Computational approach for designing thermostable Candida antarctica lipase B by molecular dynamics simulation.

PubMed

Park, Hyun June; Park, Kyungmoon; Kim, Yong Hwan; Yoo, Young Je

2014-12-20

Candida antarctica lipase B (CalB) is one of the most useful enzyme for various reactions and bioconversions. Enhancing thermostability of CalB is required for industrial applications. In this study, we propose a computational design strategy to improve the thermostability of CalB. Molecular dynamics simulations at various temperatures were used to investigate the common fluctuation sites in CalB, which are considered to be thermally weak points. The RosettaDesign algorithm was used to design the selected residues. The redesigned CalB was simulated to verify both the enhancement of intramolecular interactions and the lowering of the overall root-mean-square deviation (RMSD) values. The A251E mutant designed using this strategy showed a 2.5-fold higher thermostability than the wild-type CalB. This strategy could apply to other industry applicable enzymes. Copyright © 2014 Elsevier B.V. All rights reserved.

Coal liquefaction: A research and development needs assessment: Final report, Volume II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schindler, H.D.; Burke, F.P.; Chao, K.C.

1989-03-01

Volume II of this report on an assessment of research needs for coal liquefaction contains reviews of the five liquefaction technologies---direct, indirect, pyrolysis, coprocessing, and bioconversion. These reviews are not meant to be encyclopedic; several outstanding reviews of liquefaction have appeared in recent years and the reader is referred to these whenever applicable. Instead, these chapters contain reviews of selected topics that serve to support the panel's recommendations or to illustrate recent accomplishments, work in progress, or areas of major research interest. At the beginning of each of these chapters is a brief introduction and a summary of the mostmore » important research recommendations brought out during the panel discussions and supported by the material presented in the review. A review of liquefaction developments outside the US is included. 594 refs., 100 figs., 60 tabs.« less

Rational design of Bacillus stearothermophilus US100 L-arabinose isomerase: potential applications for D-tagatose production.

PubMed

Rhimi, Moez; Aghajari, Nushin; Juy, Michel; Chouayekh, Hichem; Maguin, Emmanuelle; Haser, Richard; Bejar, Samir

2009-05-01

L-arabinose isomerases catalyze the bioconversion of D-galactose into D-tagatose. With the aim of producing an enzyme optimized for D-tagatose production, three Bacillus stearothermophilus US100 L-arabinose isomerase mutants were constructed, purified and characterized. Our results indicate that mutant Q268K was significantly more acidotolerant and more stable at acidic pH than the wild-type enzyme. The N175H mutant has a broad optimal temperature range from 50 to 65 degrees C. With the aim of constructing an acidotolerant mutant working at relatively low temperatures we generated the Q268K/N175H construct. This double mutant displays an optimal pH in the range 6.0-7.0 and an optimal activity around 50-65 degrees C, temperatures at which the enzyme was stable without addition of metal ions.

Bioconversion of lignocellulosic biomass to xylitol: An overview.

PubMed

Venkateswar Rao, Linga; Goli, Jyosthna Khanna; Gentela, Jahnavi; Koti, Sravanthi

2016-08-01

Lignocellulosic wastes include agricultural and forest residues which are most promising alternative energy sources and serve as potential low cost raw materials that can be exploited to produce xylitol. The strong physical and chemical construction of lignocelluloses is a major constraint for the recovery of xylose. The large scale production of xylitol is attained by nickel catalyzed chemical process that is based on xylose hydrogenation, that requires purified xylose as raw substrate and the process requires high temperature and pressure that remains to be cost intensive and energy consuming. Therefore, there is a necessity to develop an integrated process for biotechnological conversion of lignocelluloses to xylitol and make the process economical. The present review confers about the pretreatment strategies that facilitate cellulose and hemicellulose acquiescent for hydrolysis. There is also an emphasis on various detoxification and fermentation methodologies including genetic engineering strategies for the efficient conversion of xylose to xylitol. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microbial and Bioconversion Production of D-xylitol and Its Detection and Application

PubMed Central

Chen, Xi; Jiang, Zi-Hua; Chen, Sanfeng; Qin, Wensheng

2010-01-01

D-Xylitol is found in low content as a natural constituent of many fruits and vegetables. It is a five-carbon sugar polyol and has been used as a food additive and sweetening agent to replace sucrose, especially for non-insulin dependent diabetics. It has multiple beneficial health effects, such as the prevention of dental caries, and acute otitis media. In industry, it has been produced by chemical reduction of D-xylose mainly from photosynthetic biomass hydrolysates. As an alternative method of chemical reduction, biosynthesis of D-xylitol has been focused on the metabolically engineered Saccharomyces cerevisiae and Candida strains. In order to detect D-xylitol in the production processes, several detection methods have been established, such as gas chromatography (GC)-based methods, high performance liquid chromatography (HPLC)-based methods, LC-MS methods, and capillary electrophoresis methods (CE). The advantages and disadvantages of these methods are compared in this review. PMID:21179590

Overproduction of cellulase by Trichoderma reesei RUT C30 through batch-feeding of synthesized low-cost sugar mixture.

PubMed

Li, Yonghao; Liu, Chenguang; Bai, Fengwu; Zhao, Xinqing

2016-09-01

Cellulase is a prerequisite for the bioconversion of lignocellulosic biomass, but its high cost presents the biggest challenge. In this article, low-cost mixture was produced from glucose through the transglycosylation reaction catalyzed by β-glucosidase for cellulase overproduction by Trichodema reesei RUT C30. As a result, cellulase titer of 90.3FPU/mL, which was more than 10 folds of that achieved with lactose as inducer, was achieved at 144h. Meanwhile, cellulase productivity was drastically increased to 627.1FPU/L/h, at least 3-5 folds higher than previously reported by the fungal species. The crude enzyme was further tested by hydrolyzing NaOH-pretreated corn stover with 15% solid loading, and 96.6g/L glucose was released with 92.6% sugar yield at 96h and 44.8g/L ethanol was obtained. Copyright © 2016 Elsevier Ltd. All rights reserved.

Action of lytic polysaccharide monooxygenase on plant tissue is governed by cellular type.

PubMed

Chabbert, Brigitte; Habrant, Anouck; Herbaut, Mickaël; Foulon, Laurence; Aguié-Béghin, Véronique; Garajova, Sona; Grisel, Sacha; Bennati-Granier, Chloé; Gimbert-Herpoël, Isabelle; Jamme, Frédéric; Réfrégiers, Matthieu; Sandt, Christophe; Berrin, Jean-Guy; Paës, Gabriel

2017-12-19

Lignocellulosic biomass bioconversion is hampered by the structural and chemical complexity of the network created by cellulose, hemicellulose and lignin. Biological conversion of lignocellulose involves synergistic action of a large array of enzymes including the recently discovered lytic polysaccharide monooxygenases (LPMOs) that perform oxidative cleavage of cellulose. Using in situ imaging by synchrotron UV fluorescence, we have shown that the addition of AA9 LPMO (from Podospora anserina) to cellulases cocktail improves the progression of enzymes in delignified Miscanthus x giganteus as observed at tissular levels. In situ chemical monitoring of cell wall modifications performed by synchrotron infrared spectroscopy during enzymatic hydrolysis demonstrated that the boosting effect of the AA9 LPMO was dependent on the cellular type indicating contrasted recalcitrance levels in plant tissues. Our study provides a useful strategy for investigating enzyme dynamics and activity in plant cell wall to improve enzymatic cocktails aimed at expanding lignocelluloses biorefinery.

Plant-microbe genomic systems optimization for energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazen, Samuel P.

The overall objective of this project was to identify genetic variation within grasses that results in increased biomass yield and biofuel conversion efficiency. Improving energy crops hinges on identifying the genetic mechanisms underlying traits that benefit energy production. The exploitation of natural variation in plant species is an ideal approach to identify both the traits and the genes of interest in the production of biofuels. The specific goals of this project were to (1) quantify relevant genetic diversity for biofuel feedstock bioconversion efficiency and biomass accumulation, (2) identify genetic loci that control these traits, and (3) characterize genes for improvedmore » energy crop systems. Determining the key genetic contributors influencing biofuel traits is required in order to determine the viability of these traits as targets for improvement; only then will we be able to apply modern breeding practices and genetic engineering for the rapid improvement of feedstocks.« less

Heliosynthesis: A solar biotechnology based on direct bioconversion of solar energy by photosynthetic cells

NASA Astrophysics Data System (ADS)

Gudin, C.

1982-12-01

Certain limiting aspects of current technology should be studied, such as the lifetimes of tubing material and the utilization of renewable sources of energy for pumping. Only exocellular or cellular biomass with high specific value, involving small markets and small plant areas (less than 1 ha), will be economically possible for the short term and will allow improvement of this technology. A valorization of the totality of photosynthetic biomass with respect to economics and energy is an absolute necessity. There is an immediate need for genetic studies of microalgae that will allow enhancement or even creation of chemical production satisfying economic and energy needs. Such efforts should permit the rapid establishment of an aggressive and sophisticated solar biotechnology that integrates scientific and technical' developments to meet the new needs of humanity for food, chemicals, and energy, thereby complementing agriculture with a sort of cellular horticulture.

Vermicomposting of source-separated human faeces by Eisenia fetida: effect of stocking density on feed consumption rate, growth characteristics and vermicompost production.

PubMed

Yadav, Kunwar D; Tare, Vinod; Ahammed, M Mansoor

2011-06-01

The main objective of the present study was to determine the optimum stocking density for feed consumption rate, biomass growth and reproduction of earthworm Eisenia fetida as well as determining and characterising vermicompost quantity and product, respectively, during vermicomposting of source-separated human faeces. For this, a number of experiments spanning up to 3 months were conducted using soil and vermicompost as support materials. Stocking density in the range of 0.25-5.00 kg/m(2) was employed in different tests. The results showed that 0.40-0.45 kg-feed/kg-worm/day was the maximum feed consumption rate by E. fetida in human faeces. The optimum stocking densities were 3.00 kg/m(2) for bioconversion of human faeces to vermicompost, and 0.50 kg/m(2) for earthworm biomass growth and reproduction. Copyright © 2011 Elsevier Ltd. All rights reserved.

Bioconversion of AHX to AOH by resting cells of Burkholderia contaminans CH-1.

PubMed

Choi, Jae-Hoon; Kikuchi, Ayaka; Pumkaeo, Panyapon; Hirai, Hirofumi; Tokuyama, Shinji; Kawagishi, Hirokazu

2016-10-01

Fairy rings are zones of stimulated grass growth owing to the interaction between a fungus and a plant. We previously reported the discovery of two novel plant-growth regulating compounds related to forming fairy rings, 2-azahypoxanthine (AHX) and 2-aza-8-oxohypoxanthine (AOH). In this study, a bacterial strain CH-1 was isolated from an airborne-contaminated nutrient medium containing AHX. The strain converted AHX to AOH and identified as Burkholderia contaminans based on the gene sequence of its 16S rDNA. The quantitative production of AOH by resting cells of the strain was achieved. Among seven Burkholderia species, two bacteria and two yeasts tested, B. contaminans CH-1 showed the highest rate of conversion of AHX to AOH. By batch system, up to 10.6 mmol AHX was converted to AOH using the resting cells. The yield of this process reached at 91%.

Willow bioenergy plantation research in the Northeast

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, E.H.; Abrahamson, L.P.; Kopp, R.F.

1993-12-31

Experiments were established in Central New York in the spring of 1987 to evaluate the potential of Salix for biomass production in bioenergy plantations. Emphasis of the research was on developing and refining establishment, tending and maintenance techniques, with complimentary study of breeding, coppice physiology, pests, nutrient use and bioconversion to energy products. Current yields utilizing salix clones developed in cooperation with the University of Toronto in short-rotation intensive culture bioenergy plantations in the Northeast approximate 8 oven dry tons per acre per year with annual harvesting. Successful clones have been identified and culture techniques refined. The results are nowmore » being integrated to establish a 100 acre Salix large-scale bioenergy farm to demonstrate current successful biomass production technology and to provide plantations of sufficient size to test harvesters; adequately assess economics of the systems; and provide large quantities of uniform biomass for pilot-scale conversion facilities.« less

Biosynthesis, structural architecture and biotechnological potential of bacterial tannase: a molecular advancement.

PubMed

Jana, Arijit; Halder, Suman Kumar; Banerjee, Amrita; Paul, Tanmay; Pati, Bikash Ranjan; Mondal, Keshab Chandra; Das Mohapatra, Pradeep Kumar

2014-04-01

Tannin-rich materials are abundantly generated as wastes from several agroindustrial activities. Therefore, tannase is an interesting hydrolase, for bioconversion of tannin-rich materials into value added products by catalyzing the hydrolysis of ester and depside bonds and unlocked a new prospect in different industrial sectors like food, beverages, pharmaceuticals, etc. Microorganisms, particularly bacteria are one of the major sources of tannase. In the last decade, cloning and heterologous expression of novel tannase genes and structural study has gained momentum. In this article, we have emphasized critically on bacterial tannase that have gained worldwide research interest for their diverse properties. The present paper delineate the developments that have taken place in understanding the role of tannase action, microbial sources, various cultivation aspects, downstream processing, salient biochemical properties, structure and active sites, immobilization, efforts in cloning and overexpression and with special emphasis on recent molecular and biotechnological achievements. Copyright © 2014 Elsevier Ltd. All rights reserved.

An overview: Recycling of solid barley waste generated as a by-product in distillery and brewery.

PubMed

Nigam, Poonam Singh

2017-04-01

This overview has focused on the options available for the utilisation of residual-biomass generated in distillery and brewery for the production of added-value products. Bio-processing approaches have been reviewed and discussed for the economical bioconversion and utilisation of this waste for the production of bioproducts, such as lactic acid, enzymes, xylitol and animal feed. Though this overview provides several options for the bioprocessing of this residual material, a more suitable one could be chosen according to the processing-facilities available and the amount of residue available in local area. The feasibility of any chosen process should be evaluated on the basis of cost of material available, its local utilisation for animal feed, and the overall economical advantages that could be gained by changing its current traditional landfill use to produce higher added value products. Copyright © 2017 Elsevier Ltd. All rights reserved.

Draft Genome Sequence of Bacillus cereus CITVM-11.1, a Strain Exhibiting Interesting Antifungal Activities.

PubMed

Caballero, Javier; Peralta, Cecilia; Molla, Antonella; Del Valle, Eleodoro E; Caballero, Primitivo; Berry, Colin; Felipe, Verónica; Yaryura, Pablo; Palma, Leopoldo

2018-01-01

Bacillus cereus is a gram-positive, spore-forming bacterium possessing an important and historical record as a human-pathogenic bacterium. However, several strains of this species exhibit interesting potential to be used as plant growth-promoting rhizobacteria. Here, we report the draft genome sequence of B. cereus strain CITVM-11.1, which consists of 37 contig sequences, accounting for 5,746,486 bp (with a GC content of 34.8%) and 5,752 predicted protein-coding sequences. Several of them could potentially be involved in plant-bacterium interactions and may contribute to the strong antagonistic activity shown by this strain against the charcoal root rot fungus, Macrophomina phaseolina. This genomic sequence also showed a number of genes that may confer this strain resistance against several polluting heavy metals and for the bioconversion of mycotoxins. © 2018 S. Karger AG, Basel.

Microbial synthesis gas utilization and ways to resolve kinetic and mass-transfer limitations.

PubMed

Yasin, Muhammad; Jeong, Yeseul; Park, Shinyoung; Jeong, Jiyeong; Lee, Eun Yeol; Lovitt, Robert W; Kim, Byung Hong; Lee, Jinwon; Chang, In Seop

2015-02-01

Microbial conversion of syngas to energy-dense biofuels and valuable chemicals is a potential technology for the efficient utilization of fossils (e.g., coal) and renewable resources (e.g., lignocellulosic biomass) in an environmentally friendly manner. However, gas-liquid mass transfer and kinetic limitations are still major constraints that limit the widespread adoption and successful commercialization of the technology. This review paper provides rationales for syngas bioconversion and summarizes the reaction limited conditions along with the possible strategies to overcome these challenges. Mass transfer and economic performances of various reactor configurations are compared, and an ideal case for optimum bioreactor operation is presented. Overall, the challenges with the bioprocessing steps are highlighted, and potential solutions are suggested. Future research directions are provided and a conceptual design for a membrane-based syngas biorefinery is proposed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bioconversion of L-phenylalanine to 2-phenylethanol by the novel stress-tolerant yeast Candida glycerinogenes WL2002-5

PubMed Central

Lu, Xinyao; Wang, Yuqin; Zong, Hong; Ji, Hao; Zhuge, Bin; Dong, Zhuoli

2016-01-01

ABSTRACT 2-Phenylethanol (2-PE) is a high value aromatic alcohol with a rose-like odor that is utilized in the cosmetics and other industries. Although the chemical routes of 2-PE production have been altered by some microbial transformation processes, the poor tolerance to organic solvents of these microorganisms has limited the 2-PE yield. In this study, the stress-tolerant yeast Candida glycerinogenes WL2002-5 showed a 2-PE tolerance to 4 g/l, which is the highest reported to date. Moreover, the 2-PE titer in a batch fermentation from L-phenylalanine reached 5g/l, which is the highest level achieved by fermentation without in situ product recovery. These results suggest C. glycerinogenes WL2002-5 is a robust strain for the bioproduction of 2-PE with potential for commercial exploitation. PMID:27435817

Bioconversion of L-phenylalanine to 2-phenylethanol by the novel stress-tolerant yeast Candida glycerinogenes WL2002-5.

PubMed

Lu, Xinyao; Wang, Yuqin; Zong, Hong; Ji, Hao; Zhuge, Bin; Dong, Zhuoli

2016-11-01

2-Phenylethanol (2-PE) is a high value aromatic alcohol with a rose-like odor that is utilized in the cosmetics and other industries. Although the chemical routes of 2-PE production have been altered by some microbial transformation processes, the poor tolerance to organic solvents of these microorganisms has limited the 2-PE yield. In this study, the stress-tolerant yeast Candida glycerinogenes WL2002-5 showed a 2-PE tolerance to 4 g/l, which is the highest reported to date. Moreover, the 2-PE titer in a batch fermentation from L-phenylalanine reached 5g/l, which is the highest level achieved by fermentation without in situ product recovery. These results suggest C. glycerinogenes WL2002-5 is a robust strain for the bioproduction of 2-PE with potential for commercial exploitation.

Bio-conversion of water hyacinths into methane gas, part 1

NASA Technical Reports Server (NTRS)

Wolverton, B. C.; Mcdonald, R. C.; Gordon, J.

1974-01-01

Bio-gas and methane production from the microbial anaerobic decomposition of water hyacinths (Eichhornia crassipes) (Mart) Solms was investigated. These experiments demonstrated the ability of water hyacinths to produce an average of 13.9 ml of methane gas per gram of wet plant weight. This study revealed that sample preparation had no significant effect on bio-gas and/or methane production. Pollution of water hyacinths by two toxic heavy materials, nickel and cadmium, increased the rate of methane production from 51.8 ml/day for non-contaminated plants incubated at 36 C to 81.0 ml/day for Ni-Cd contaminated plants incubated at the same temperature. The methane content of bio-gas evolved from the anaerobic decomposition of Ni-Cd contaminated plants was 91.1 percent as compared to 69.2 percent methane content of bio-gas collected from the fermentation of non-contaminated plants.

Development of Chemical and Metabolite Sensors for Rhodococcus opacus PD630.

PubMed

DeLorenzo, Drew M; Henson, William R; Moon, Tae Seok

2017-10-20

Rhodococcus opacus PD630 is a nonmodel, Gram-positive bacterium that possesses desirable traits for biomass conversion, including consumption capabilities for lignocellulose-based sugars and toxic lignin-derived aromatic compounds, significant triacylglycerol accumulation, relatively rapid growth rate, and genetic tractability. However, few genetic elements have been directly characterized in R. opacus, limiting its application for lignocellulose bioconversion. Here, we report the characterization and development of genetic tools for tunable gene expression in R. opacus, including: (1) six fluorescent reporters for quantifying promoter output, (2) three chemically inducible promoters for variable gene expression, and (3) two classes of metabolite sensors derived from native R. opacus promoters that detect nitrogen levels or aromatic compounds. Using these tools, we also provide insights into native aromatic consumption pathways in R. opacus. Overall, this work expands the ability to control and characterize gene expression in R. opacus for future lignocellulose-based fuel and chemical production.

Advances in the enzymatic production of L-hexoses.

PubMed

Chen, Ziwei; Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

2016-08-01

Rare sugars have recently drawn attention because of their potential applications and huge market demands in the food and pharmaceutical industries. All L-hexoses are considered rare sugars, as they rarely occur in nature and are thus very expensive. L-Hexoses are important components of biologically relevant compounds as well as being used as precursors for certain pharmaceutical drugs and thus play an important role in the pharmaceutical industry. Many general strategies have been established for the synthesis of L-hexoses; however, the only one used in the biotechnology industry is the Izumoring strategy. In hexose Izumoring, four entrances link the D- to L-enantiomers, ketose 3-epimerases catalyze the C-3 epimerization of L-ketohexoses, and aldose isomerases catalyze the specific bioconversion of L-ketohexoses and the corresponding L-aldohexoses. In this article, recent studies on the enzymatic production of various L-hexoses are reviewed based on the Izumoring strategy.

Steam explosion pretreatment for enhancing biogas production of late harvested hay.

PubMed

Bauer, Alexander; Lizasoain, Javier; Theuretzbacher, Franz; Agger, Jane W; Rincón, María; Menardo, Simona; Saylor, Molly K; Enguídanos, Ramón; Nielsen, Paal J; Potthast, Antje; Zweckmair, Thomas; Gronauer, Andreas; Horn, Svein J

2014-08-01

Grasslands are often abandoned due to lack of profitability. Extensively cultivating grassland for utilization in a biogas-based biorefinery concept could mend this problem. Efficient bioconversion of this lignocellulosic biomass requires a pretreatment step. In this study the effect of different steam explosion conditions on hay digestibility have been investigated. Increasing severity in the pretreatment induced degradation of the hemicellulose, which at the same time led to the production of inhibitors and formation of pseudo-lignin. Enzymatic hydrolysis showed that the maximum glucose yields were obtained under pretreatment at 220 °C for 15 min, while higher xylose yields were obtained at 175 °C for 10 min. Pretreatment of hay by steam explosion enhanced 15.9% the methane yield in comparison to the untreated hay. Results indicate that hay can be effectively converted to methane after steam explosion pretreatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cost and greenhouse gas emission tradeoffs of alternative uses of lignin for second generation ethanol

NASA Astrophysics Data System (ADS)

Pourhashem, Ghasideh; Adler, Paul R.; McAloon, Andrew J.; Spatari, Sabrina

2013-06-01

Second generation ethanol bioconversion technologies are under demonstration-scale development for the production of lignocellulosic fuels to meet the US federal Renewable Fuel Standards (RFS2). Bioconversion technology utilizes the fermentable sugars generated from the cellulosic fraction of the feedstock, and most commonly assumes that the lignin fraction may be used as a source of thermal and electrical energy. We examine the life cycle greenhouse gas (GHG) emission and techno-economic cost tradeoffs for alternative uses of the lignin fraction of agricultural residues (corn stover, and wheat and barley straw) produced within a 2000 dry metric ton per day ethanol biorefinery in three locations in the United States. We compare three scenarios in which the lignin is (1) used as a land amendment to replace soil organic carbon (SOC); (2) separated, dried and sold as a coal substitute to produce electricity; and (3) used to produce electricity onsite at the biorefinery. Results from this analysis indicate that for life cycle GHG intensity, amending the lignin to land is lowest among the three ethanol production options (-25 to -2 g CO2e MJ-1), substituting coal with lignin is second lowest (4-32 g CO2e MJ-1), and onsite power generation is highest (36-41 g CO2e MJ-1). Moreover, the onsite power generation case may not meet RFS2 cellulosic fuel requirements given the uncertainty in electricity substitution. Options that use lignin for energy do so at the expense of SOC loss. The lignin-land amendment option has the lowest capital cost among the three options due to lower equipment costs for the biorefinery’s thermal energy needs and use of biogas generated onsite. The need to purchase electricity and uncertain market value of the lignin-land amendment could raise its cost compared to onsite power generation and electricity co-production. However, assuming a market value (50-100/dry Mg) for nutrient and soil carbon replacement in agricultural soils, and potentially economy of scale residue collection prices at higher collection volumes associated with low SOC loss, the lignin-land amendment option is economically and environmentally preferable, with the lowest GHG abatement costs relative to gasoline among the three lignin co-product options we consider.

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol.

PubMed

Li, Jihong; Li, Shizhong; Han, Bing; Yu, Menghui; Li, Guangming; Jiang, Yan

2013-11-29

Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions.

Genome sequence and comparative analysis of a putative entomopathogenic Serratia isolated from Caenorhabditis briggsae.

PubMed

Abebe-Akele, Feseha; Tisa, Louis S; Cooper, Vaughn S; Hatcher, Philip J; Abebe, Eyualem; Thomas, W Kelley

2015-07-18

Entomopathogenic associations between nematodes in the genera Steinernema and Heterorhabdus with their cognate bacteria from the bacterial genera Xenorhabdus and Photorhabdus, respectively, are extensively studied for their potential as biological control agents against invasive insect species. These two highly coevolved associations were results of convergent evolution. Given the natural abundance of bacteria, nematodes and insects, it is surprising that only these two associations with no intermediate forms are widely studied in the entomopathogenic context. Discovering analogous systems involving novel bacterial and nematode species would shed light on the evolutionary processes involved in the transition from free living organisms to obligatory partners in entomopathogenicity. We report the complete genome sequence of a new member of the enterobacterial genus Serratia that forms a putative entomopathogenic complex with Caenorhabditis briggsae. Analysis of the 5.04 MB chromosomal genome predicts 4599 protein coding genes, seven sets of ribosomal RNA genes, 84 tRNA genes and a 64.8 KB plasmid encoding 74 genes. Comparative genomic analysis with three of the previously sequenced Serratia species, S. marcescens DB11 and S. proteamaculans 568, and Serratia sp. AS12, revealed that these four representatives of the genus share a core set of ~3100 genes and extensive structural conservation. The newly identified species shares a more recent common ancestor with S. marcescens with 99% sequence identity in rDNA sequence and orthology across 85.6% of predicted genes. Of the 39 genes/operons implicated in the virulence, symbiosis, recolonization, immune evasion and bioconversion, 21 (53.8%) were present in Serratia while 33 (84.6%) and 35 (89%) were present in Xenorhabdus and Photorhabdus EPN bacteria respectively. The majority of unique sequences in Serratia sp. SCBI (South African Caenorhabditis briggsae Isolate) are found in ~29 genomic islands of 5 to 65 genes and are enriched in putative functions that are biologically relevant to an entomopathogenic lifestyle, including non-ribosomal peptide synthetases, bacteriocins, fimbrial biogenesis, ushering proteins, toxins, secondary metabolite secretion and multiple drug resistance/efflux systems. By revealing the early stages of adaptation to this lifestyle, the Serratia sp. SCBI genome underscores the fact that in EPN formation the composite end result - killing, bioconversion, cadaver protection and recolonization- can be achieved by dissimilar mechanisms. This genome sequence will enable further study of the evolution of entomopathogenic nematode-bacteria complexes.

A novel cost-effective technology to convert sucrose and homocelluloses in sweet sorghum stalks into ethanol

PubMed Central

2013-01-01

Background Sweet sorghum is regarded as a very promising energy crop for ethanol production because it not only supplies grain and sugar, but also offers lignocellulosic resource. Cost-competitive ethanol production requires bioconversion of all carbohydrates in stalks including of both sucrose and lignocellulose hydrolyzed into fermentable sugars. However, it is still a main challenge to reduce ethanol production cost and improve feasibility of industrial application. An integration of the different operations within the whole process is a potential solution. Results An integrated process combined advanced solid-state fermentation technology (ASSF) and alkaline pretreatment was presented in this work. Soluble sugars in sweet sorghum stalks were firstly converted into ethanol by ASSF using crushed stalks directly. Then, the operation combining ethanol distillation and alkaline pretreatment was performed in one distillation-reactor simultaneously. The corresponding investigation indicated that the addition of alkali did not affect the ethanol recovery. The effect of three alkalis, NaOH, KOH and Ca(OH)2 on pretreatment were investigated. The results indicated the delignification of lignocellulose by NaOH and KOH was more significant than that by Ca(OH)2, and the highest removal of xylan was caused by NaOH. Moreover, an optimized alkali loading of 10% (w/w DM) NaOH was determined. Under this favorable pretreatment condition, enzymatic hydrolysis of sweet sorghum bagasse following pretreatment was investigated. 92.0% of glucan and 53.3% of xylan conversion were obtained at enzyme loading of 10 FPU/g glucan. The fermentation of hydrolyzed slurry was performed using an engineered stain, Zymomonas mobilis TSH-01. A mass balance of the overall process was calculated, and 91.9 kg was achieved from one tonne of fresh sweet sorghum stalk. Conclusions A low energy-consumption integrated technology for ethanol production from sweet sorghum stalks was presented in this work. Energy consumption for raw materials preparation and pretreatment were reduced or avoided in our process. Based on this technology, the recalcitrance of lignocellulose was destructed via a cost-efficient process and all sugars in sweet sorghum stalks lignocellulose were hydrolysed into fermentable sugars. Bioconversion of fermentable sugars released from sweet sorghum bagasse into different products except ethanol, such as butanol, biogas, and chemicals was feasible to operate under low energy-consumption conditions. PMID:24286508

Auto-flotation of heterocyst enables the efficient production of renewable energy in cyanobacteria

PubMed Central

Chen, Ming; Li, Jihong; Zhang, Lei; Chang, Sandra; Liu, Chen; Wang, Jianlong; Li, Shizhong

2014-01-01

Utilizing cyanobacteria as a bioenergy resource is difficult due to the cost and energy consuming harvests of microalgal biomass. In this study, an auto-floating system was developed by increasing the photobiological H2 production in the heterocysts of filamentous cyanobacteria. An amount of 1.0 μM of diuron, which inhibited O2 production in cyanobacteria, resulted in a high rate of H2 production in heterocysts. The auto-floating process recovered 91.71% ± 1.22 of the accumulated microalgal biomass from the liquid media. Quantification analysis revealed that 0.72–1.10 μmol H2 per mg dry weight microalgal biomass was necessary to create this auto-floating system. Further bio-conversion by using anaerobic digestion converted the harvested microalgal biomass into biogas. Through this novel coupled system of photobiological H2 production and anaerobic digestion, a high level of light energy conversion efficiency from solar energy to bioenergy was attained with the values of 3.79% ± 0.76. PMID:24499777

Assessment of different pretreatment technologies for efficient bioconversion of lignocellulose to ethanol.

PubMed

Singh, Jitendra K; Vyas, Preeti; Dubey, Anamika; Upadhyaya, Chandrama Prakash; Kothari, Richa; Tyagi, Vineet Veer; Kumar, Ashwani

2018-06-01

The future supply of energy to meet growing energy demand of rapidly exapanding populations is based on wide energy resources, particularly the renewable ones. Among all resources, lignocellulosic biomasses such as agriculture, forest, and agro-industrial residues are the most abundant and easily available bioresource for biorefineries to provide fuels, chemicals, and materials. However, pretreatment of biomass is required to overcome the physical and chemical barriers that exist in the lignin-carbohydrate composite and pretreatment facilitate the entry of biocatalysts for the conversion of biomass into fermentable sugars and other by-products. Therefore, pretreatment of the biomass is necessary prerequisite for efficient hydrolysis of lignocelluloses into different type of fermentable sugars. The physiochemical, biochemical and biological pretreatment methods are considered as most promising technologies for the biomass hydrolysis and are discussed in this review article. We also discussed the recent advancements and modern trends in pretreatment methods of lignocelluloses conversion into ethanol with special focus on fermentation methods.

Bioconversion of volatile fatty acids derived from waste activated sludge into lipids by Cryptococcus curvatus.

PubMed

Liu, Jia; Liu, Jia-Nan; Yuan, Ming; Shen, Zi-Heng; Peng, Kai-Ming; Lu, Li-Jun; Huang, Xiang-Feng

2016-07-01

Pure volatile fatty acid (VFA) solution derived from waste activated sludge (WAS) was used to produce microbial lipids as culture medium in this study, which aimed to realize the resource recovery of WAS and provide low-cost feedstock for biodiesel production simultaneously. Cryptococcus curvatus was selected among three oleaginous yeast to produce lipids with VFAs derived from WAS. In batch cultivation, lipid contents increased from 10.2% to 16.8% when carbon to nitrogen ratio increased from about 3.5 to 165 after removal of ammonia nitrogen by struvite precipitation. The lipid content further increased to 39.6% and the biomass increased from 1.56g/L to 4.53g/L after cultivation for five cycles using sequencing batch culture (SBC) strategy. The lipids produced from WAS-derived VFA solution contained nearly 50% of monounsaturated fatty acids, including palmitic acid, heptadecanoic acid, ginkgolic acid, stearic acid, oleic acid, and linoleic acid, which showed the adequacy of biodiesel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dissecting the effect of chemical additives on the enzymatic hydrolysis of pretreated wheat straw.

PubMed

Monschein, Mareike; Reisinger, Christoph; Nidetzky, Bernd

2014-10-01

Chemical additives were examined for ability to increase the enzymatic hydrolysis of thermo-acidically pretreated wheat straw by Trichoderma reesei cellulase at 50 °C. Semi-empirical descriptors derived from the hydrolysis time courses were applied to compare influence of these additives on lignocellulose bioconversion on a kinetic level, presenting a novel view on their mechanism of action. Focus was on rate retardation during hydrolysis, substrate conversion and enzyme adsorption. PEG 8000 enabled a reduction of enzyme loading by 50% while retaining the same conversion of 67% after 24h. For the first time, a beneficial effect of urea is reported, increasing the final substrate conversion after 48 h by 16%. The cationic surfactant cetyl-trimethylammonium bromide (CTAB) enhanced the hydrolysis rate at extended reaction time (rlim) by 34% and reduced reaction time by 28%. A combination of PEG 8000 and urea increased sugar release more than additives used individually. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tart Cherries and health: Current knowledge and need for a better understanding of the fate of phytochemicals in the human gastrointestinal tract.

PubMed

Alba C, Mayta-Apaza; Daya, Marasini; Franck, Carbonero

2017-09-28

Tart cherries are increasingly popular due to purported health benefits. This Prunus cesarus species is cultivated worldwide, and its market has increased significantly in the last two decades due to improvements in agricultural practices and food processing technology. Tart cherries are rich in polyphenols, with a very specific profile combining anthocyanins and flavonols (berries-like) and chlorogenic acid (coffee-like). Tart cherries have been suggested to exert several potentially beneficial health effects including: lowering blood pressure, modulating blood glucose, enhancing cognitive function, protecting against oxidative stress and reducing inflammation. Studies focusing on tart cherry consumption have demonstrated particular benefits in recovery from exercise-induced muscle damage and diabetes associated parameters. However, the bioconversion of tart cherry polyphenols by resident colonic microbiota has never been considered, considerably reducing the impact of in vitro studies that have relied on fruit polyphenol extracts. In vitro and in vivo gut microbiota and metabolome studies are necessary to reinforce health claims linked to tart cherries consumption.

Trends in food waste valorization for the production of chemicals, materials and fuels: Case study South and Southeast Asia.

PubMed

Ong, Khai Lun; Kaur, Guneet; Pensupa, Nattha; Uisan, Kristiadi; Lin, Carol Sze Ki

2018-01-01

Staggering amounts of food waste are being generated in Asia by means of agricultural processing, food transportation and storage, and human food consumption activities. This along with the recent sustainable development goals of food security, environmental protection, and energy efficiency are the key drivers for food waste valorization. The aim of this review is to provide an insight on the latest trends in food waste valorization in Asian countries such as India, Thailand, Singapore, Malaysia and Indonesia. Landfilling, incineration, and composting are the first-generation food waste processing technologies. The advancement of valorisation alternatives to tackle the food waste issue is the focus of this review. Furthermore, a series of examples of key food waste valorization schemes in this Asian region as case studies to demonstrate the advancement in bioconversions in these countries are described. Finally, important legislation aspects for food waste disposal in these Asian countries are also reported. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bio-conversion of water hyacinths into methane gas. Part 1. [Effects of cadmium and nickel pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolverton, B.C.; Mcdonald, R.C.; Gordon, J.

1974-07-01

Bio-gas and methane production from the microbial anaerobic decomposition of water hyacinths (Eichhornia crassipes) (Mart) Solms was investigated. These experiments demonstrated the ability of water hyacinths to produce an average of 13.9 ml of methane gas per gram of wet plant weight. This study revealed that sample preparation had no significant effect on bio-gas and/or methane production. Pollution of water hyacinths by two toxic heavy materials, nickel and cadmium, increased the rate of methane production from 51.8 ml/day for non-contaminated plants incubated at 36 C to 81.0 ml/day for Ni-Cd contaminated plants incubated at the same temperature. The methane contentmore » of bio-gas evolved from the anaerobic decomposition of Ni-Cd contaminated plants was 91.1 percent as compared to 69.2 percent methane content of bio-gas collected from the fermentation of non-contaminated plants. (Author) (GRA)« less

Bioethanol production from raffinate phase of supercritical CO2 extracted Stevia rebaudiana leaves.

PubMed

Coban, Isik; Sargin, Sayit; Celiktas, Melih Soner; Yesil-Celiktas, Ozlem

2012-09-01

The extracts of Stevia rebaudiana are marketed as dietary supplements and utilized as natural sweetening agent in food products. Subsequent to extraction on industrial scale, large quantities of solid wastes are produced. The aim of this study was to investigate the bioconversion efficiency of supercritical CO(2) extracted S. rebaudiana residues. Therefore, leaves were extracted with supercritical CO(2) and ethanol mixture in order to obtain glycosides, then the raffinate phase was hydrolyzed by both dilute acid and various concentrations of cellulase and β-glucosidase cocktail. The maximum yield of reducing sugars reached 25.67 g/L under the optimal conditions of enzyme pretreatment, whereas 32.00 g/L was reached by consecutive enzymatic and acid hydrolyses. Bioethanol yield (20 g/L, 2.0% inoculum, 2 days) based on the sugar consumed was 45.55% corresponding to a productivity of 0.19 kg/m(3)h which demonstrates challenges to be utilized as a potential feedstock for the production of bioethanol. Copyright © 2012 Elsevier Ltd. All rights reserved.

Chip calorimetry for evaluation of biofilm treatment with biocides, antibiotics, and biological agents.

PubMed

Morais, Frida Mariana; Buchholz, Friederike; Maskow, Thomas

2014-01-01

Any growth or bioconversion in biofilms is accompanied by the release of heat. The heat (in J) is tightly related to the stoichiometry of the respective process via law of Hess, and the heat production rate (in W or J/s) is additionally related to the process kinetics. This heat and the heat production rate can nowadays be measured by modern calorimetry with extremely high sensitivity. Flow-through calorimetry allows the measurement of bioprocesses in biofilms in real time, without the need of invasive sample preparation and disturbing of biofilm processes. Furthermore, it can be applied for long-term measurements and is even applicable to turbid media. Chip or miniaturized calorimeters have the additional advantages of extremely short thermal equilibration times and the requirement of very small amounts of media and chemicals. The precision of flow-through chip calorimeters (about 3 mW/L) allows the detection of early stages of biofilm development (about 10(5) bacteria cm(-2)).

Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

PubMed

Dikshit, Pritam Kumar; Moholkar, Vijayanand S

2016-09-01

The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improved Release and Metabolism of Flavonoids by Steered Fermentation Processes: A Review

PubMed Central

Nguyen Thai, Huynh; Van Camp, John; Smagghe, Guy; Raes, Katleen

2014-01-01

This paper provides an overview on steered fermentation processes to release phenolic compounds from plant-based matrices, as well as on their potential application to convert phenolic compounds into unique metabolites. The ability of fermentation to improve the yield and to change the profile of phenolic compounds is mainly due to the release of bound phenolic compounds, as a consequence of the degradation of the cell wall structure by microbial enzymes produced during fermentation. Moreover, the microbial metabolism of phenolic compounds results in a large array of new metabolites through different bioconversion pathways such as glycosylation, deglycosylation, ring cleavage, methylation, glucuronidation and sulfate conjugation, depending on the microbial strains and substrates used. A whole range of metabolites is produced, however metabolic pathways related to the formation and bioactivities, and often quantification of the metabolites are highly underinvestigated. This strategy could have potential to produce extracts with a high-added value from plant-based matrices. PMID:25347275

Enzyme conversion of lignocellulosic plant materials for resource recovery in a controlled ecological life support system

NASA Astrophysics Data System (ADS)

Kohlmann, K. L.; Westgate, P.; Velayudhan, A.; Weil, J.; Sarikaya, A.; Brewer, M. A.; Hendrickson, R. L.; Ladisch, M. R.

1996-01-01

A large amount of inedible plant material composed primarily of the carbohydrate materials cellulose, hemicellulose, and lignin is generated as a result of plant growth in a Controlled Ecological Life-Support System (CELSS). Cellulose is a linear homopolymer of glucose, which when properly processed will yield glucose, a valuable sugar because it can be added directly to human diets. Hemicellulose is a heteropolymer of hexoses and pentoses that can be treated to give a sugar mixture that is potentially a valuable fermentable carbon source. Such fermentations yield desirable supplements to the edible products from hydroponically-grown plants such as rapeseed, soybean, cowpea, or rice. Lignin is a three-dimensionally branched aromatic polymer, composed of phenyl propane units, which is susceptible to bioconversion through the growth of the white rot fungus, Pluerotus ostreatus. Processing conditions, that include both a hot water pretreatment and fungal growth and that lead to the facile conversion of plant polysaccharides to glucose, are presented.

Biogasification of sorghum in a novel anaerobic digester

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srivastava, V.J.; Biljetina, R.; Isaacson, H.R.

1987-01-01

The Institute of Gas Technology (IGT) conducted pilot-scale anaerobic digestion experiments with ensiled sorghum in a 160 ft/sup 3/ digester at the experimental test unit (ETU) facility at the Walt Disney World Resort Complex in Florida. The study focused on improving bioconversion efficiencies and process stability by employing a novel reactor concept developed at IGT. Steady-state performance data were collected from the ETU as well as from a laboratory-scale conventional stirred tank reactor (CSTR) at loading rates of 0.25 and 0.50 lb organic matter/ft/sup 3/-day at mesophilic and thermophilic temperatures, respectively. This paper will describe the ETU facility, novel digestermore » design and operating techniques, and the results obtained during 12 months of stable and uninterrupted operation of the ETU and the CSTR which showed that methane yields anad rates from the ETU were 20% to 50% higher than those of the CSTR. 10 refs., 7 figs., 5 tabs.« less

Differential reinforcement of enzymatic hydrolysis by adding chemicals and accessory proteins to high solid loading substrates with different pretreatments.

PubMed

Du, Jian; Song, Wenxia; Zhang, Xiu; Zhao, Jian; Liu, Guodong; Qu, Yinbo

2018-04-23

High dosage of enzyme is required to achieve effective lignocellulose hydrolysis, especially at high-solid loadings, which is a significant barrier to large-scale bioconversion of lignocellulose. Here, we screened four chemical additives and three accessory proteins for their effects on the enzymatic hydrolysis of various lignocellulosic materials. The effects were found to be highly dependent on the composition and solid loadings of substrates. For xylan-extracted lignin-rich corncob residue, the enhancing effect of PEG 6000 was most pronounced and negligibly affected by solid content, which reduced more than half of enzyme demand at 20% dry matter (DM). Lytic polysaccharide monooxygenase enhanced the hydrolysis of ammonium sulfite wheat straw pulp, and its addition reduced about half of protein demand at the solid loading of 20% DM. Supplementation of the additives in the hydrolysis of pure cellulose and complex lignocellulosic materials revealed that their effects are tightly linked to pretreatment strategies.

Role of bifidobacteria in the hydrolysis of chlorogenic acid

PubMed Central

Raimondi, Stefano; Anighoro, Andrew; Quartieri, Andrea; Amaretti, Alberto; Tomás-Barberán, Francisco A; Rastelli, Giulio; Rossi, Maddalena

2015-01-01

This study aimed to explore the capability of potentially probiotic bifidobacteria to hydrolyze chlorogenic acid into caffeic acid (CA), and to recognize the enzymes involved in this reaction. Bifidobacterium strains belonging to eight species occurring in the human gut were screened. The hydrolysis seemed peculiar of Bifidobacterium animalis, whereas the other species failed to release CA. Intracellular feruloyl esterase activity capable of hydrolyzing chlorogenic acid was detected only in B. animalis. In silico research among bifidobacteria esterases identified Balat_0669 as the cytosolic enzyme likely responsible of CA release in B. animalis. Comparative modeling of Balat_0669 and molecular docking studies support its role in chlorogenic acid hydrolysis. Expression, purification, and functional characterization of Balat_0669 in Escherichia coli were obtained as further validation. A possible role of B. animalis in the activation of hydroxycinnamic acids was demonstrated and new perspectives were opened in the development of new probiotics, specifically selected for the enhanced bioconversion of phytochemicals into bioactive compounds. PMID:25515139

Role of bifidobacteria in the hydrolysis of chlorogenic acid.

PubMed

Raimondi, Stefano; Anighoro, Andrew; Quartieri, Andrea; Amaretti, Alberto; Tomás-Barberán, Francisco A; Rastelli, Giulio; Rossi, Maddalena

2015-02-01

This study aimed to explore the capability of potentially probiotic bifidobacteria to hydrolyze chlorogenic acid into caffeic acid (CA), and to recognize the enzymes involved in this reaction. Bifidobacterium strains belonging to eight species occurring in the human gut were screened. The hydrolysis seemed peculiar of Bifidobacterium animalis, whereas the other species failed to release CA. Intracellular feruloyl esterase activity capable of hydrolyzing chlorogenic acid was detected only in B. animalis. In silico research among bifidobacteria esterases identified Balat_0669 as the cytosolic enzyme likely responsible of CA release in B. animalis. Comparative modeling of Balat_0669 and molecular docking studies support its role in chlorogenic acid hydrolysis. Expression, purification, and functional characterization of Balat_0669 in Escherichia coli were obtained as further validation. A possible role of B. animalis in the activation of hydroxycinnamic acids was demonstrated and new perspectives were opened in the development of new probiotics, specifically selected for the enhanced bioconversion of phytochemicals into bioactive compounds. © 2014 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Bioconversion of Capsaicin by Aspergillus oryzae.

PubMed

Lee, Minji; Cho, Jeong-Yong; Lee, Yu Geon; Lee, Hyoung Jae; Lim, Seong-Il; Park, So-Lim; Moon, Jae-Hak

2015-07-08

This study identified metabolites of capsaicin bioconverted by Aspergillus oryzae, which is generally used for mass production of gochujang prepared by fermenting red pepper powder in Korea. A. oryzae was incubated with capsaicin in potato dextrose broth. Capsaicin decreased depending on the incubation period, but new metabolites increased. Five capsaicin metabolites purified from the ethyl acetate fraction of the capsaicin culture were identified as N-vanillylcarbamoylbutyric acid, N-vanillyl-9-hydroxy-8-methyloctanamide, ω-hydroxycapsaicin, 8-methyl-N-vanillylcarbamoyl-6(E)-octenoic acid, and 2-methyl-N-vanillylcarbamoyl-6(Z)-octenoic acid by nuclear magnetic resonance (NMR) and mass spectrometry (MS). The capsaicin metabolites in gochujang were confirmed and quantitated by selective multiple reaction monitoring detection after liquid chromatography electrospray ionization MS using the isolated compounds as external standards. On the basis of the structures of the capsaicin metabolites, it is proposed that capsaicin metabolites were converted by A. oryzae by ω-hydroxylation, alcohol oxidation, hydrogenation, isomerization, and α- and/or β-oxidation.

Assessment of Two Solid Anaerobic Digestate Soil Amendments for Effects on Soil Quality and Biosolarization Efficacy.

PubMed

Fernández-Bayo, Jesús D; Achmon, Yigal; Harrold, Duff R; McCurry, Dlinka G; Hernandez, Katie; Dahlquist-Willard, Ruth M; Stapleton, James J; VanderGheynst, Jean S; Simmons, Christopher W

2017-05-03

Anaerobic digestion is an organic waste bioconversion process that produces biofuel and digestates. Digestates have potential to be applied as soil amendment to improve properties for crop production including phytonutrient content and pest load. Our objective was to assess the impact of solid anaerobic digestates on weed seed inactivation and soil quality upon soil biosolarization (a pest control technique that combines solar heating and amendment-induced microbial activity). Two solid digestates from thermophilic (TD) and mesophilic (MD) digesters were tested. The solarized TD-amended samples presented significantly higher mortality of Brassica nigra (71%, P = 0.032) than its equivalent incubated at room temperature. However, biosolarization with digestate amendment led to decreased weed seed mortality in certain treatments. The plant-available water, total C, and extractable P and K were significantly increased (P < 0.05) in the incubated amended soils. The results confirm the potential of digestates as beneficial soil amendments. Further studies are needed to elucidate the impacts of digestate stability on biosolarization efficacy and soil properties.

Changes of microbial population structure related to lignin degradation during lignocellulosic waste composting.

PubMed

Huang, Dan-Lian; Zeng, Guang-Ming; Feng, Chong-Ling; Hu, Shuang; Lai, Cui; Zhao, Mei-Hua; Su, Feng-Feng; Tang, Lin; Liu, Hong-Liang

2010-06-01

Microbial populations and their relationship to bioconversion during lignocellulosic waste composting were studied by quinone profiling. Nine quinones were observed in the initial composting materials, and 15 quinones were found in compost after 50days of composting. The quinone species Q-9(H2), Q-10 and Q-10(H2) which are indicative of certain fungi appeared at the thermophilic stage but disappeared at the cooling stage. Q-10, indicative of certain fungi, and MK-7, characteristic of certain bacteria, were the predominant quinones during the thermophilic stage and were correlated with lignin degradation at the thermophilic stage. The highest lignin degradation ratio (26%) and good cellulose degradation were found at the cooling stage and were correlated with quinones Q-9, MK-7 and long-chain menaquinones attributed to mesophilic fungi, bacteria and actinomycetes, respectively. The present findings will improve the understandings of microbial dynamics and roles in composting, which could provide useful references for development of composting technology. Copyright 2010. Published by Elsevier Ltd.

Alternative energy technologies for the Caribbean islands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pytlinski, J.T.

1992-01-01

All islands in the Caribbean except Puerto Rico can be classified as developing islands. Of these islands, all except Trinidad and Tobago are oil importers. Uncertainties concerning uninterrupted oil supply and increasing oil prices causes economic, social and political instability and jeopardizes further development of these islands. The paper discusses the energy situation of the Caribbean islands and presents alternative energy options. Several alternative energy projects financed by local, federal and international organizations are presented. Present and future uses of alternative energy technologies are described in different islands. Barrier which handicap developing and implementing alternative energy sources in the Caribbeanmore » are discussed. The potential and possible applications of alternative energy technologies such as: solar-thermal energy, photovoltaics, wind energy, ocean thermal energy conversion (OTEC), ocean currents and tides energy, biomass, peat energy, municipal solid wastes, bioconversion, hydropower, geothermal energy, nuclear energy and energy conservation are discussed in detail as means to alleviate the energy situation in the Caribbean islands.« less

Bioconversion of wastewater from sweet potato starch production to Paenibacillus polymyxa biofertilizer for tea plants.

PubMed

Xu, Shengjun; Bai, Zhihui; Jin, Bo; Xiao, Runlin; Zhuang, Guoqiang

2014-02-28

Wastewater from the sweet potato starch industry is a large source of nutrient-rich substrates. We assessed whether this wastewater could be used to produce Paenibacillus polymyxa biofertilizer for foliar application to tea trees. Using the central composite design methods we experientially determined that the optimal culture conditions for P. polymyxa were pH, 6.5; temperature, 29.0 °C; and incubation time, 16 h. Under these conditions, a maximum biomass of 9.7 × 10(9) cfu/mL was achieved. We then conducted a yearlong field investigation to determine the effect of P. polymyxa biofertilizer on the growth of tea plants (Camellia sinensis). Tea yield, quantity of water extract, and tea polyphenol levels were significantly higher after foliar application of the biofertilizer compared to that in the controls by an average of 16.7%, 6.3%, and 10.4%, respectively. This approach appears to be technically feasible for organic tea production, and is an environmentally friendly way to utilize wastewater.

Bioconversion of wastewater from sweet potato starch production to Paenibacillus polymyxa biofertilizer for tea plants

PubMed Central

Xu, Shengjun; Bai, Zhihui; Jin, Bo; Xiao, Runlin; Zhuang, Guoqiang

2014-01-01

Wastewater from the sweet potato starch industry is a large source of nutrient-rich substrates. We assessed whether this wastewater could be used to produce Paenibacillus polymyxa biofertilizer for foliar application to tea trees. Using the central composite design methods we experientially determined that the optimal culture conditions for P. polymyxa were pH, 6.5; temperature, 29.0°C; and incubation time, 16 h. Under these conditions, a maximum biomass of 9.7 × 109 cfu/mL was achieved. We then conducted a yearlong field investigation to determine the effect of P. polymyxa biofertilizer on the growth of tea plants (Camellia sinensis). Tea yield, quantity of water extract, and tea polyphenol levels were significantly higher after foliar application of the biofertilizer compared to that in the controls by an average of 16.7%, 6.3%, and 10.4%, respectively. This approach appears to be technically feasible for organic tea production, and is an environmentally friendly way to utilize wastewater. PMID:24576979

Microbial enzymes with special characteristics for biotechnological applications.

PubMed

Nigam, Poonam Singh

2013-08-23

This article overviews the enzymes produced by microorganisms, which have been extensively studied worldwide for their isolation, purification and characterization of their specific properties. Researchers have isolated specific microorganisms from extreme sources under extreme culture conditions, with the objective that such isolated microbes would possess the capability to bio-synthesize special enzymes. Various Bio-industries require enzymes possessing special characteristics for their applications in processing of substrates and raw materials. The microbial enzymes act as bio-catalysts to perform reactions in bio-processes in an economical and environmentally-friendly way as opposed to the use of chemical catalysts. The special characteristics of enzymes are exploited for their commercial interest and industrial applications, which include: thermotolerance, thermophilic nature, tolerance to a varied range of pH, stability of enzyme activity over a range of temperature and pH, and other harsh reaction conditions. Such enzymes have proven their utility in bio-industries such as food, leather, textiles, animal feed, and in bio-conversions and bio-remediations.

Impact of anti-acidification microbial consortium on carbohydrate metabolism of key microbes during food waste composting.

PubMed

Song, Caihong; Li, Mingxiao; Qi, Hui; Zhang, Yali; Liu, Dongming; Xia, Xunfeng; Pan, Hongwei; Xi, Beidou

2018-07-01

This study investigated the effect of anti-acidification microbial consortium (AAMC), which act synergistically for rapid bioconversion of organic acids on carbohydrate metabolism of key microbes in the course of food waste (FW) composting by metaproteomics. AAMC was inoculated to the composting mass and compared with treatment with alkaline compounds and the control without any amendment. Inoculating AAMC could effectively accelerate carbohydrate degradation process and improve composting efficiency. Carbohydrate metabolic network profiles showed the inoculation with AAMC could increase significantly the types of enzymes catalysing the degradation of lignin, cellulose and hemicellulose. Furthermore, AAMC inoculum could increase not only diversities of microbes producing key enzymes in metabolism pathways of acetic and propionic acids, but also the amounts of these key enzymes. The increase of diversities of microbes could disperse the pressure from acidic adversity on microorganisms which were capable to degrade acetic and propionic acids. Copyright © 2018 Elsevier Ltd. All rights reserved.

Auto-flotation of heterocyst enables the efficient production of renewable energy in cyanobacteria.

PubMed

Chen, Ming; Li, Jihong; Zhang, Lei; Chang, Sandra; Liu, Chen; Wang, Jianlong; Li, Shizhong

2014-02-06

Utilizing cyanobacteria as a bioenergy resource is difficult due to the cost and energy consuming harvests of microalgal biomass. In this study, an auto-floating system was developed by increasing the photobiological H2 production in the heterocysts of filamentous cyanobacteria. An amount of 1.0 μM of diuron, which inhibited O2 production in cyanobacteria, resulted in a high rate of H2 production in heterocysts. The auto-floating process recovered 91.71% ± 1.22 of the accumulated microalgal biomass from the liquid media. Quantification analysis revealed that 0.72-1.10 μmol H2 per mg dry weight microalgal biomass was necessary to create this auto-floating system. Further bio-conversion by using anaerobic digestion converted the harvested microalgal biomass into biogas. Through this novel coupled system of photobiological H2 production and anaerobic digestion, a high level of light energy conversion efficiency from solar energy to bioenergy was attained with the values of 3.79% ± 0.76.

A review on bioconversion of lignocellulosic biomass to H2: Key challenges and new insights.

PubMed

Ren, Nan-Qi; Zhao, Lei; Chen, Chuan; Guo, Wan-Qian; Cao, Guang-Li

2016-09-01

With the increasing energy crisis and rising concern over climate change, the development of clean alternative energy sources is of great importance. Biohydrogen produced from lignocellulosic biomass is a promising candidate, because of its positives such as readily available, no harmful emissions, environment friendly, efficient, and renewable. However, obstacles still exist to enable the commercialization of biological hydrogen production from lignocellulosic biomass. Thus the objective of this work is to provide update information about the recent progress on lignocellulosic hydrogen conversion via dark fermentation. In this review, the most important technologies associated with lignocellulosic hydrogen fermentation were covered. Firstly, pretreatment methods for better utilization of lignocellulosic biomass are presented, at the same time, hydrolysis methods assisting to achieve efficient hydrogen fermentation were discussed. Afterwards, issues related to bioprocesses for hydrogen production purposes were presented. Additionally, the paper gave challenges and new insights of lignocellulosic biohydrogen production. Copyright © 2016. Published by Elsevier Ltd.

Development of Chemical and Metabolite Sensors for Rhodococcus opacus PD630

DOE PAGES

DeLorenzo, Drew M.; Henson, William R.; Moon, Tae Seok

2017-07-26

Rhodococcus opacus PD630 is a non-model, gram positive bacterium that possesses desirable traits for biomass conversion, including consumption capabilities for lignocellulose-based sugars and toxic lignin-derived aromatic compounds, significant triacylglycerol accumulation, relatively rapid growth rate, and genetic tractability. However, few genetic elements have been directly characterized in R. opacus, limiting its application for lignocellulose bioconversion. Here, we report the characterization and development of genetic tools for tunable gene expression in R. opacus, including: 1) six fluorescent reporters for quantifying promoter output, 2) three chemically inducible promoters for variable gene expression, and 3) two classes of metabolite sensors derived from native R.more » opacus promoters that detect nitrogen levels or aromatic compounds. Using these tools, we also provide insights into native aromatic consumption pathways in R. opacus. Overall, this work expands the ability to control and characterize gene expression in R. opacus for future lignocellulose-based fuel and chemical production.« less

Malolactic bioconversion using a Oenococcus oeni strain for cider production: effect of yeast extract supplementation.

PubMed

Herrero, Mónica; García, Luis A; Díaz, Mario

2003-12-01

Yeast extract addition to reconstituted apple juice had a positive impact on the development of the malolactic starter culture used to ensure malolactic fermentation in cider, using active but non-proliferating cells. In this work, the reuse of fermentation lees from cider is proposed as an alternative to the use of commercial yeast extract products. Malolactic enzymatic assays, both in whole cells and cell-free extracts, were carried out to determine the best time to harvest cells for use as an inoculum in cider. Cells harvested at the late exponential phase, the physiological stage of growth corresponding to the maximum values of specific malolactic activity, achieved a good rate of malic acid degradation in controlled cider fermentation. Under the laboratory conditions used, malic acid degradation rates in the fermentation media turned out to be near 2.0 and 2.5 times lower, compared with the rates obtained in whole-cell enzymatic assays, as useful data applicable to industrial cider production.

Xylose-fermenting Pichia stipitis by genome shuffling for improved ethanol production.

PubMed

Shi, Jun; Zhang, Min; Zhang, Libin; Wang, Pin; Jiang, Li; Deng, Huiping

2014-03-01

Xylose fermentation is necessary for the bioconversion of lignocellulose to ethanol as fuel, but wild-type Saccharomyces cerevisiae strains cannot fully metabolize xylose. Several efforts have been made to obtain microbial strains with enhanced xylose fermentation. However, xylose fermentation remains a serious challenge because of the complexity of lignocellulosic biomass hydrolysates. Genome shuffling has been widely used for the rapid improvement of industrially important microbial strains. After two rounds of genome shuffling, a genetically stable, high-ethanol-producing strain was obtained. Designated as TJ2-3, this strain could ferment xylose and produce 1.5 times more ethanol than wild-type Pichia stipitis after fermentation for 96 h. The acridine orange and propidium iodide uptake assays showed that the maintenance of yeast cell membrane integrity is important for ethanol fermentation. This study highlights the importance of genome shuffling in P. stipitis as an effective method for enhancing the productivity of industrial strains. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Selective bio-oxidation of propane to acetone using methane-oxidizing Methylomonas sp. DH-1.

PubMed

Hur, Dong Hoon; Nguyen, Thu Thi; Kim, Donghyuk; Lee, Eun Yeol

2017-07-01

Propane is the major component of liquefied petroleum gas (LPG). Nowadays, the use of LPG is decreasing, and thus utilization of propane as a chemical feedstock is in need of development. An efficient biological conversion of propane to acetone using a methanotrophic whole cell as the biocatalyst was proposed and investigated. A bio-oxidation pathway of propane to acetone in Methylomonas sp. DH-1 was analyzed by gene expression profiling via RNA sequencing. Propane was oxidized to 2-propanol by particulate methane monooxygenase and subsequently to acetone by methanol dehydrogenases. Methylomonas sp. DH-1 was deficient in acetone-converting enzymes and thus accumulated acetone in the absence of any enzyme inhibition. The maximum accumulation, average productivity and specific productivity of acetone were 16.62 mM, 0.678 mM/h and 0.141 mmol/g cell/h, respectively, under the optimized conditions. Our study demonstrates a novel method for the bioconversion of propane to acetone using methanotrophs under mild reaction condition.

Genetic Tools for the Industrially Promising Methanotroph Methylomicrobium buryatense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puri, AW; Owen, S; Chu, F

2015-02-10

Aerobic methanotrophs oxidize methane at ambient temperatures and pressures and are therefore attractive systems for methane-based bioconversions. In this work, we developed and validated genetic tools for Methylomicrobium buryatense, a haloalkaliphilic gammaproteobacterial (type I) methanotroph. M. buryatense was isolated directly on natural gas and grows robustly in pure culture with a 3-h doubling time, enabling rapid genetic manipulation compared to many other methanotrophic species. As a proof of concept, we used a sucrose counterselection system to eliminate glycogen production in M. buryatense by constructing unmarked deletions in two redundant glycogen synthase genes. We also selected for a more genetically tractablemore » variant strain that can be conjugated with small incompatibility group P (IncP)-based broad-host-range vectors and determined that this capability is due to loss of the native plasmid. These tools make M. buryatense a promising model system for studying aerobic methanotroph physiology and enable metabolic engineering in this bacterium for industrial biocatalysis of methane.« less

Recent advances in yeast cell-surface display technologies for waste biorefineries.

PubMed

Liu, Zhuo; Ho, Shih-Hsin; Hasunuma, Tomohisa; Chang, Jo-Shu; Ren, Nan-Qi; Kondo, Akihiko

2016-09-01

Waste biorefinery aims to maximize the output of value-added products from various artificial/agricultural wastes by using integrated bioprocesses. To make waste biorefinery economically feasible, it is thus necessary to develop a low-cost, environment-friendly technique to perform simultaneous biodegradation and bioconversion of waste materials. Cell-surface display engineering is a novel, cost-effective technique that can auto-immobilize proteins on the cell exterior of microorganisms, and has been applied for use with waste biofinery. Through tethering different enzymes (e.g., cellulase, lipase, and protease) or metal-binding peptides on cell surfaces, various yeast strains can effectively produce biofuels and biochemicals from sugar/protein-rich waste materials, catalyze waste oils into biodiesels, or retrieve heavy metals from wastewater. This review critically summarizes recent applications of yeast cell-surface display on various types of waste biorefineries, highlighting its potential and future challenges with regard to commercializing this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dry fractionation process as an important step in current and future lignocellulose biorefineries: a review.

PubMed

Barakat, Abdellatif; de Vries, Hugo; Rouau, Xavier

2013-04-01

The use of lignocellulosic biomass is promising for biofuels and materials and new technologies for the conversion need to be developed. However, the inherent properties of native lignocellulosic materials make them resistant to enzymatic and chemical degradation. Lignocellulosic biomass requires being pretreated to change the physical and chemical properties of lignocellulosic matrix in order to increase cell wall polymers accessibility and bioavailability. Mechanical size reduction may be chemical free intensive operation thanks to decreasing particles size and cellulose crystallinity, and increasing accessible surface area. Changes in these parameters improve the digestibility and the bioconversion of lignocellulosic biomass. However, mechanical size reduction requires cost-effective approaches from an energy input point of view. Therefore, the energy consumption in relation to physicochemical properties of lignocellulosic biomass was discussed. Even more, chemical treatments combined with physicochemical size reduction approaches are proposed to reduce energy consumption in this review. Copyright © 2013 Elsevier Ltd. All rights reserved.

Engineering the cell wall by reducing de-methyl-esterified homogalacturonan improves saccharification of plant tissues for bioconversion.

PubMed

Lionetti, Vincenzo; Francocci, Fedra; Ferrari, Simone; Volpi, Chiara; Bellincampi, Daniela; Galletti, Roberta; D'Ovidio, Renato; De Lorenzo, Giulia; Cervone, Felice

2010-01-12

Plant cell walls represent an abundant, renewable source of biofuel and other useful products. The major bottleneck for the industrial scale-up of their conversion to simple sugars (saccharification), to be subsequently converted by microorganisms into ethanol or other products, is their recalcitrance to enzymatic saccharification. We investigated whether the structure of pectin that embeds the cellulose-hemicellulose network affects the exposure of cellulose to enzymes and consequently the process of saccharification. Reduction of de-methyl-esterified homogalacturonan (HGA) in Arabidopsis plants through the expression of a fungal polygalacturonase (PG) or an inhibitor of pectin methylesterase (PMEI) increased the efficiency of enzymatic saccharification. The improved enzymatic saccharification efficiency observed in transformed plants could also reduce the need for acid pretreatment. Similar results were obtained in PG-expressing tobacco plants and in PMEI-expressing wheat plants, indicating that reduction of de-methyl-esterified HGA may be used in crop species to facilitate the process of biomass saccharification.

Acetone-butanol Fermentation of Marine Macroalgae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huesemann, Michael H.; Kuo, Li-Jung; Urquhart, Lindsay A.

2012-03-01

Mannitol and laminarin, which are present at high concentrations in the brown macroalga Saccharina spp., a type of kelp, are potential biochemical feedstocks for butanol production. To test their bioconversion potential, aqueous extracts of the kelp Saccharina spp., mannitol, and glucose (a product of laminarin hydrolysis) were subjected to acetone-butanol fermentation by Clostridium acetobutylicum (ATCC 824). Both mannitol and glucose were readily fermented. Mixed substrate fermentations with glucose and mannitol resulted in diauxic growth of C. acetobutylicum with glucose depletion preceding mannitol utilization. Fermentation of kelp extract exhibited triauxic growth, with an order of utilization of free glucose, mannitol, andmore » bound glucose, presumably laminarin. The lag in laminarin utilization reflected the need for enzymatic hydrolysis of this polysaccharide into fermentable sugars. The butanol and total solvent yields were 0.12 g/g and 0.16 g/g, respectively, indicating that significant improvements are still needed to make industrial-scale acetone-butanol fermentations of seaweed economically feasible.« less

Mini review: hydrogen and ethanol co-production from waste materials via microbial fermentation.

PubMed

Soo, Chiu-Shyan; Yap, Wai-Sum; Hon, Wei-Min; Phang, Lai-Yee

2015-10-01

The simultaneous production of hydrogen and ethanol by microorganisms from waste materials in a bioreactor system would establish cost-effective and time-saving biofuel production. This review aims to present the current status of fermentation processes producing hydrogen accompanied by ethanol as a co-product. We outlined the microbes used and their fundamental pathways for hydrogen and ethanol fermentation. Moreover, we discussed the exploitation of renewable and sustainable waste materials as promising feedstock and the limitations encountered. The low substrate bioconversion rate in hydrogen and ethanol co-production is regarded as the primary constraint towards the development of large scale applications. Thus, microbes with an enhanced capability have been generated via genetic manipulation to diminish the inefficiency of substrate consumption. In this review, other potential approaches to improve the performance of co-production through fermentation were also elaborated. This review will be a useful guide for the future development of hydrogen and ethanol co-production using waste materials.

High glucose recovery from direct enzymatic hydrolysis of bisulfite-pretreatment on non-detoxified furfural residues.

PubMed

Xing, Yang; Bu, Lingxi; Sun, Dafeng; Liu, Zhiping; Liu, Shijie; Jiang, Jianxin

2015-10-01

This study reports four schemes to pretreat wet furfural residues (FRs) with sodium bisulfite for production of fermentable sugar. The results showed that non-detoxified FRs (pH 2-3) had great potential to lower the cost of bioconversion. The optimal process was that unwashed FRs were first pretreated with bisulfite, and the whole slurry was then directly used for enzymatic hydrolysis. A maximum glucose yield of 99.4% was achieved from substrates pretreated with 0.1 g NaHSO3/g dry substrate (DS), at a relatively low temperature of 100 °C for 3 h. Compared with raw material, enzymatic hydrolysis at a high-solid of 16.5% (w/w) specifically showed more excellent performance with bisulfite treated FRs. Direct bisulfite pretreatment improved the accessibility of substrates and the total glucose recovery. Lignosulfonate in the non-detoxified slurry decreased the non-productive adsorption of cellulase on the substrate, thus improving enzymatic hydrolysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Fermented Red Ginseng Extract Enriched in Ginsenoside Rg3 on the Differentiation and Mineralization of Preosteoblastic MC3T3-E1 Cells

PubMed Central

Siddiqi, Muhammad Zubair; Siddiqi, Muhammad Hanif; Jin, Yan; Huq, Md. Amdadul

2015-01-01

Abstract In this study, red ginseng extract (RGE) was converted into high-content minor ginsenosides by fermenting with Bgp1 enzymes at 37°C for 5 days. Compared to the RGE, the minor ginsenoside contents were increased in fermented red ginseng extract (FRGE). Moreover, the amount of minor ginsenosides such as Rh1 (11%) and Rg2 (16%) was slightly augmented, while the level of Rg3 (33%) was significantly increased after bioconversion. Furthermore, we also examined and compared the effect of RGE and FRGE on the differentiation and mineralization of preosteoblastic MC3T3-E1 cells. Similarly, the level of mRNA expression of intracellular alkaline phosphatase (ALP) activity, type-1 collagen (Col-I) was also increased. Based on the comparison, it is clear that the FRGE has improved effects on bone formation and differentiation of preosteoblastic MC3T3-E1 cells. PMID:25764149

Simultaneous utilization of cellobiose, xylose, and acetic acid from lignocellulosic biomass for biofuel production by an engineered yeast platform.

PubMed

Wei, Na; Oh, Eun Joong; Million, Gyver; Cate, Jamie H D; Jin, Yong-Su

2015-06-19

The inability of fermenting microorganisms to use mixed carbon components derived from lignocellulosic biomass is a major technical barrier that hinders the development of economically viable cellulosic biofuel production. In this study, we integrated the fermentation pathways of both hexose and pentose sugars and an acetic acid reduction pathway into one Saccharomyces cerevisiae strain for the first time using synthetic biology and metabolic engineering approaches. The engineered strain coutilized cellobiose, xylose, and acetic acid to produce ethanol with a substantially higher yield and productivity than the control strains, and the results showed the unique synergistic effects of pathway coexpression. The mixed substrate coutilization strategy is important for making complete and efficient use of cellulosic carbon and will contribute to the development of consolidated bioprocessing for cellulosic biofuel. The study also presents an innovative metabolic engineering approach whereby multiple substrate consumption pathways can be integrated in a synergistic way for enhanced bioconversion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pace, Sara; Ceballos, Shannon J.; Harrold, Duff

Our aims were to identify thermophilic microbial communities that degrade green waste in the presence of the ionic liquids (IL) tetrabutylphosphonium chloride and tributylethylphosphonium diethylphosphate and examine preservation methods for IL-tolerant communities. High-solids incubations with stepwise increases in IL concentration were conducted to enrich for thermophilic IL-tolerant communities that decomposed green waste. 16S rRNA sequencing of enriched communities revealed microorganisms capable of tolerating high levels of IL. Furthermore, cryogenic preservation of enriched communities reduced the IL tolerance of the community and decreased the relative abundance of IL-tolerant organisms. The use of cryoprotectants did not have an effect on microbial activitymore » on green waste of the stored community. A successful approach was developed to enrich communities that decompose green waste in thermophilic high-solids environments in the presence of IL. Alternative community storage and revival methods are necessary for maintenance and recovery of IL-tolerant communities. The enriched communities provide a targeted source of enzymes for the bioconversion of IL-pretreated green waste for conversion to biofuels.« less

The acid tolerant L-arabinose isomerase from the food grade Lactobacillus sakei 23K is an attractive D-tagatose producer.

PubMed

Rhimi, Moez; Ilhammami, Rimeh; Bajic, Goran; Boudebbouze, Samira; Maguin, Emmanuelle; Haser, Richard; Aghajari, Nushin

2010-12-01

The araA gene encoding an L-arabinose isomerase (L-AI) from the psychrotrophic and food grade Lactobacillus sakei 23K was cloned, sequenced and over-expressed in Escherichia coli. The recombinant enzyme has an apparent molecular weight of nearly 220 kDa, suggesting it is a tetramer of four 54 kDa monomers. The enzyme is distinguishable from previously reported L-AIs by its high activity and stability at temperatures from 4 to 40 degrees C, and pH from 3 to 8, and by its low metal requirement of only 0.8 mM Mn(2+) and 0.8 mM Mg(2+) for its maximal activity and thermostability. Enzyme kinetic studies showed that this enzyme displays a high catalytic efficiency allowing D-galactose bioconversion rates of 20% and 36% at 10 and 45 degrees C, respectively, which are useful for commercial production of D-tagatose. 2010 Elsevier Ltd. All rights reserved.

Macrocyclic Prodrugs of a Selective Nonpeptidic Direct Thrombin Inhibitor Display High Permeability, Efficient Bioconversion but Low Bioavailability.

PubMed

Andersson, Vincent; Bergström, Fredrik; Brånalt, Jonas; Grönberg, Gunnar; Gustafsson, David; Karlsson, Staffan; Polla, Magnus; Bergman, Joakim; Kihlberg, Jan

2016-07-28

The only oral direct thrombin inhibitors that have reached the market, ximelagatran and dabigatran etexilat, are double prodrugs with low bioavailability in humans. We have evaluated an alternative strategy: the preparation of a nonpeptidic, polar direct thrombin inhibitor as a single, macrocyclic esterase-cleavable (acyloxy)alkoxy prodrug. Two homologous prodrugs were synthesized and displayed high solubilities and Caco-2 cell permeabilities, suggesting high absorption from the intestine. In addition, they were rapidly and completely converted to the active zwitterionic thrombin inhibitor in human hepatocytes. Unexpectedly, the most promising prodrug displayed only moderately higher oral bioavailability in rat than the polar direct thrombin inhibitor, most likely due to rapid metabolism in the intestine or the intestinal wall. To the best of our knowledge, this is the first in vivo ADME study of macrocyclic (acyloxy)alkoxy prodrugs, and it remains to be established if the modest increase in bioavailability is a general feature of this category of prodrugs or not.

Multi-scale process and supply chain modelling: from lignocellulosic feedstock to process and products

PubMed Central

Hosseini, Seyed Ali; Shah, Nilay

2011-01-01

There is a large body of literature regarding the choice and optimization of different processes for converting feedstock to bioethanol and bio-commodities; moreover, there has been some reasonable technological development in bioconversion methods over the past decade. However, the eventual cost and other important metrics relating to sustainability of biofuel production will be determined not only by the performance of the conversion process, but also by the performance of the entire supply chain from feedstock production to consumption. Moreover, in order to ensure world-class biorefinery performance, both the network and the individual components must be designed appropriately, and allocation of resources over the resulting infrastructure must effectively be performed. The goal of this work is to describe the key challenges in bioenergy supply chain modelling and then to develop a framework and methodology to show how multi-scale modelling can pave the way to answer holistic supply chain questions, such as the prospects for second generation bioenergy crops. PMID:22482032

Bioconversion of sugar cane crop residues with white-rot fungiPleurotus sp.

PubMed

Ortega, G M; Martínez, E O; Betancourt, D; González, A E; Otero, M A

1992-07-01

Four mushroom strains ofPleurotus spp. were cultivated on sugar cane crop residues for 30 days at 26°C. Biochemical changes affected the substrate as a result of fungal growth, in terms of nitrogen, lignin, cellulose and hemicellulose contents. All strains showed a strong ligninolytic activity together with variable cellulolytic and xylanolytic action.Pleurotus sajor-caju attacked lignin and cellulose at the same rate, showing a degradation of 47% and 55%, respectively. A better balance was shown by theP. ostreatus-P. pulmonarius hybrid, which exhibited the poorest cellulolytic action (39%) and the highest ligninolytic activity (67%). The average composition of mushroom fruit bodies, in terms of nitrogen, carbohydrates, fats and amino acid profiles, was determined. Crude protein and total carbohydrate varied from 23% to 33% and 36% to 68% of dry matter, respectively. Fat ranged from 3.3% to 4.7% and amino acid content from 12.2% to 22.2%. Slight evidence for a nitrogen fixing capability was encountered in the substrate to fruit body balance.

Reusing ethyl acetate and aqueous exhausted fractions of dry olive mill residue by saprobe fungi.

PubMed

Aranda, E; García-Romera, I; Ocampo, J A; Carbone, V; Malorni, A; Sannino, F; De Martino, A; Capasso, R

2007-01-01

Some saprobe fungi (Phlebia radiata, Trametes versicolor, Coriolopsis rigida, Pycnoporus cinnabarinus, Fomes sclerodermus or Pleurotus pulmonarius) were able to bioconvert the ethyl acetate fraction (DEAF) and the corresponding aqueous exhausted fraction (EAF) of dry olive mill residue (DOR), reducing their phytotoxicity on Lepidium sativum seeds. Large amount of hydroxytyrosol together with other eight monomeric phenols were found in the native DEAF fraction, which represents a good source of antioxidants. P. radiata, T. versicolor and F. sclerodermus caused an effective phytotoxicity reduction of EAF in the concentration range of 25-3 gl(-1). In particular, in the range between 12.5 and 3 gl(-1), the EAF samples inoculated with P. radiata and F. sclerodermus surprisingly stimulated the germinability of L. sativum, suggesting their use as a potential biofertilizer. This is the first report which showed the bioconversion of the above fractions in shorter time with respect to the previous findings concerning DOR. The possible implications of laccase in the decrease of DEAF and EAF phytotoxicity was also discussed.

Temperature and pH influence adsorption of cellobiohydrolase onto lignin by changing the protein properties.

PubMed

Lu, Xianqin; Wang, Can; Li, Xuezhi; Zhao, Jian

2017-12-01

Non-productive adsorption of cellulase onto lignin restricted the movement of cellulase and also hindered the cellulase recycling in bioconversion of lignocellulose. In this study, effect of temperature and pH on adsorption and desorption of cellobiohydrolase (CBH) on lignin and its possible mechanism were discussed. It found that pH value and temperature influenced the adsorption and desorption behaviors of CBH on lignin. Different thermodynamic models suggested that the action between lignin and CBH was physical action. More CBH was adsorbed onto lignin, but lower initial adsorption velocity was detected at 50°C comparing with 4°C. Elevating pH value could improve desorption of cellulase from lignin. The changes of hydrophobicity and electric potential on protein surface may partially explain the impact of environmental conditions on the adsorption and desorption behaviors of CBH on lignin, and comparing to electrical interaction, the hydrophobicity may be the dominating factor influencing the behaviors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioconversion of paper mill sludge to bioethanol in the presence of accelerants or hydrogen peroxide pretreatment.

PubMed

Gurram, Raghu Nandan; Al-Shannag, Mohammad; Lecher, Nicholas Joshua; Duncan, Shona M; Singsaas, Eric Lawrence; Alkasrawi, Malek

2015-09-01

In this study we investigated the technical feasibility of convert paper mill sludge into fuel ethanol. This involved the removal of mineral fillers by using either chemical pretreatment or mechanical fractionation to determine their effects on cellulose hydrolysis and fermentation to ethanol. In addition, we studied the effect of cationic polyelectrolyte (as accelerant) addition and hydrogen peroxide pretreatment on enzymatic hydrolysis and fermentation. We present results showing that removing the fillers content (ash and calcium carbonate) from the paper mill sludge increases the enzymatic hydrolysis performance dramatically with higher cellulose conversion at faster rates. The addition of accelerant and hydrogen peroxide pretreatment further improved the hydrolysis yields by 16% and 25% (g glucose / g cellulose), respectively with the de-ashed sludge. The fermentation process of produced sugars achieved up to 95% of the maximum theoretical ethanol yield and higher ethanol productivities within 9h of fermentation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ensilage and bioconversion of grape pomace into fuel ethanol.

PubMed

Zheng, Yi; Lee, Christopher; Yu, Chaowei; Cheng, Yu-Shen; Simmons, Christopher W; Zhang, Ruihong; Jenkins, Bryan M; VanderGheynst, Jean S

2012-11-07

Two types of grape pomace were ensiled with eight strains of lactic acid bacteria (LAB). Both fresh grape pomace (FrGP) and fermented grape pomace (FeGP) were preserved through alcoholic fermentation but not malolactic conversion. Water leaching prior to storage was used to reduce water-soluble carbohydrates and ethanol from FrGP and FeGP, respectively, to increase malolactic conversion. Leached FeGP had spoilage after 28 days of ensilage, whereas FrGP was preserved. Dilute acid pretreatment was examined for increasing the conversion of pomace to ethanol via Escherichia coli KO11 fermentation. Dilute acid pretreatment doubled the ethanol yield from FeGP, but it did not improve the ethanol yield from FrGP. The ethanol yields from raw pomace were nearly double the yields from the ensiled pomace. For this reason, the recovery of ethanol produced during winemaking from FeGP and ethanol produced during storage of FrGP is critical for the economical conversion of grape pomace to biofuel.

Glycyrrhiza glabra (Linn.) and Lavandula officinalis (L.) cell suspension cultures-based biotransformation of β-artemether.

PubMed

Patel, Suman; Gaur, Rashmi; Upadhyaya, Mohita; Mathur, Archana; Mathur, Ajay K; Bhakuni, Rajendra S

2011-07-01

The biotransformation of β-artemether (1) by cell suspension cultures of Glycyrrhiza glabra and Lavandula officinalis is reported here for the first time. The major biotransformed product appeared as a grayish-blue color spot on thin-layer chromatography (TLC) with transparent crystal-like texture. Based on its infrared (IR) and (1)H nuclear magnetic resonance (NMR) spectra, the product was characterized as a tetrahydrofuran (THF)-acetate derivative (2). The highest conversion efficiencies of 57 and 60% were obtained when 8-9-day-old cell suspensions of G. glabra and L. officinalis were respectively fed with 4-7 mg of compound 1 in 40 ml of medium per culture and the cells were harvested after 2-5 days of incubation. The addition of compound 1 at the beginning of the culture cycle caused severe growth depression in a dose-dependent manner, resulting in poor bioconversion efficiency of ~25% at 2-5 mg/culture dose only.

High-yield production of mannitol by Leuconostoc pseudomesenteroides CTCC G123 from chicory-derived inulin hydrolysate.

PubMed

Zhang, Min; Gu, Lei; Cheng, Chao; Zhu, Junru; Wu, Hao; Ma, Jiangfeng; Dong, Weiliang; Kong, Xiangping; Jiang, Min; Ouyang, Pingkai

2017-08-01

Chicory is an agricultural plant with considerable potential as a carbohydrate substrate for low-cost production of biochemicals. In this work, the production of mannitol by Leuconostoc pseudomesenteroides CTCC G123 from chicory-derived inulin hydrolysate was investigated. The bioconversion process initially suffered from the leakage of fructose to the phosphoketolase pathway, resulting in a low mannitol yield. When inulin hydrolysate was supplemented with glucose as a substrate for mannitol production in combination with aeration induction and nicotinic acid induced redox modulation strategies, the mannitol yield greatly improved. Under these conditions, significant improvement in the glucose consumption rate, intracellular NADH levels and mannitol dehydrogenase specific activity were observed, with mannitol production increasing from 64.6 to 88.1 g/L and overall yield increase from 0.69 to 0.94 g/g. This work demonstrated an efficient method for the production of mannitol from inulin hydrolysate with a high overall yield.

Modeling of acetate-type fermentation of sugar-containing wastewater under acidic pH conditions.

PubMed

Huang, Liang; Pan, Xin-Rong; Wang, Ya-Zhou; Li, Chen-Xuan; Chen, Chang-Bin; Zhao, Quan-Bao; Mu, Yang; Yu, Han-Qing; Li, Wen-Wei

2018-01-01

In this study, a kinetic model was developed based on Anaerobic Digestion Model No. 1 to provide insights into the directed production of acetate and methane from sugar-containing wastewater under low pH conditions. The model sufficiently described the dynamics of liquid-phase and gaseous products in an anaerobic membrane bioreactor by comprehensively considering the syntrophic bioconversion steps of sucrose hydrolysis, acidogenesis, acetogenesis and methanogenesis under acidic pH conditions. The modeling results revealed a significant pH-dependency of hydrogenotrophic methanogenesis and ethanol-producing processes that govern the sucrose fermentative pathway through changing the hydrogen yield. The reaction thermodynamics of such acetate-type fermentation were evaluated, and the implications for process optimization by adjusting the hydraulic retention time were discussed. This work sheds light on the acid-stimulated acetate-type fermentation process and may lay a foundation for optimization of resource-oriented processes for treatment of food wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous saccharification of inulin and starch using commercial glucoamylase and the subsequent bioconversion to high titer sorbitol and gluconic acid.

PubMed

An, Kehong; Hu, Fengxian; Bao, Jie

2013-12-01

A new bioprocess for production of sorbitol and gluconic acid from two low-cost feedstocks, inulin and cassava starch, using a commercially available enzyme was proposed in this study. The commercial glucoamylase GA-L NEW from Genencor was found to demonstrate a high inulinase activity for hydrolysis of inulin into fructose and glucose. The glucoamylase was used to replace the expensive and not commercially available inulinase enzyme for simultaneous saccharification of inulin and starch into high titer glucose and fructose hydrolysate. The glucose and fructose in the hydrolysate were converted into sorbitol and gluconic acid using immobilized whole cells of the recombinant Zymomonas mobilis strain. The high gluconic acid concentration of 193 g/L and sorbitol concentration of 180 g/L with the overall yield of 97.3 % were obtained in the batch operations. The present study provided a practical production method of sorbitol and gluconic acid from low cost feedstocks and enzymes.

Thermostable, haloalkaline cellulase from Bacillus halodurans CAS 1 by conversion of lignocellulosic wastes.

PubMed

Annamalai, Neelamegam; Rajeswari, Mayavan Veeramuthu; Elayaraja, Sivaramasamy; Balasubramanian, Thangavel

2013-04-15

An extracellular thermostable, haloalkaline cellulase by bioconversion of lignocellulosic wastes from Bacillus halodurans CAS 1 was purified to homogeneity with recovery of 12.54% and purity fold 7.96 with the molecular weight of 44 kDa. The optimum temperature, pH and NaCl for enzyme activity was determined as 60°C, 9.0 and 30% and it retained 80% of activity even at 80°C, 12 and 35% respectively. The activity was greatly inhibited by EDTA, indicating that it was a metalloenzyme and significant inhibition by PMSF revealed that serine residue was essential for catalytic activity. The purified cellulase hydrolyzed CMC, cellobiose and xylan, but not avicel, cellulose and PNPG. Furthermore, the cellulase was highly stable in the presence of detergents and organic solvents such as acetone, n-hexane and acetonitrile. Thus, the purified cellulase from B. halodurans utilizing lignocellulosic biomass could be greatly useful to develop industrial processes. Published by Elsevier Ltd.

Effect of SBR feeding strategy and feed composition on the stability of aerobic granular sludge in the treatment of a simulated textile wastewater.

PubMed

Franca, R D G; Ortigueira, J; Pinheiro, H M; Lourenço, N D

2017-09-01

Treatment of the highly polluting and variable textile industry wastewater using aerobic granular sludge (AGS) sequencing batch reactors (SBRs) has been recently suggested. Aiming to develop this technology application, two feeding strategies were compared regarding the capacity of anaerobic-aerobic SBRs to deal with disturbances in the composition of the simulated textile wastewater feed. Both a statically fed, anaerobic-aerobic SBR and an anaerobic plug-flow fed, anaerobic-aerobic SBR could cope with shocks of high azo dye concentration and organic load, the overall chemical oxygen demand and color removal yields being rapidly restored to 80%. Yet, subsequent azo dye metabolite bioconversion was not observed, along the 315-day run. Moreover, switching from a starch-based substrate to acetate in the feed composition deteriorated AGS stability. Overall, the plug-flow fed SBR recovered more rapidly from the imposed disturbances. Further research is needed towards guaranteeing long-term AGS stability during the treatment of textile wastewater.

Anaerobic Membrane Bioreactor for Continuous Lactic Acid Fermentation

PubMed Central

Fan, Rong; Ebrahimi, Mehrdad; Czermak, Peter

2017-01-01

Membrane bioreactor systems can enhance anaerobic lactic acid fermentation by reducing product inhibition, thus increasing productivity. In batch fermentations, the bioconversion of glucose is strongly inhibited in the presence of more than 100 g·L−1 lactic acid and is only possible when the product is simultaneously removed, which can be achieved by ceramic membrane filtration. The crossflow velocity is a more important determinant of flux than the transmembrane pressure. Therefore, to stabilize the performance of the membrane bioreactor system during continuous fermentation, the crossflow velocity was controlled by varying the biomass concentration, which was monitored in real-time using an optical sensor. Continuous fermentation under these conditions, thus, achieved a stable productivity of ~8 g·L−1·h−1 and the concentration of lactic acid was maintained at ~40 g·L−1 at a dilution rate of 0.2 h−1. No residual sugar was detected in the steady state with a feed concentration of 50 g·L−1. PMID:28467384

Enzyme conversion of lignocellulosic plant materials for resource recovery in a Controlled Ecological Life Support System

NASA Technical Reports Server (NTRS)

Kohlmann, K. L.; Westgate, P.; Velayudhan, A.; Weil, J.; Sarikaya, A.; Brewer, M. A.; Hendrickson, R. L.; Ladisch, M. R.; Mitchell, C. A. (Principal Investigator)

1996-01-01

A large amount of inedible plant material composed primarily of the carbohydrate materials cellulose, hemicellulose, and lignin is generated as a result of plant growth in a Controlled Ecological Life-Support System (CELSS). Cellulose is a linear homopolymer of glucose, which when properly processed will yield glucose, a valuable sugar because it can be added directly to human diets. Hemicellulose is a heteropolymer of hexoses and pentoses that can be treated to give a sugar mixture that is potentially a valuable fermentable carbon source. Such fermentations yield desirable supplements to the edible products from hydroponically-grown plants such as rapeseed, soybean, cowpea, or rice. Lignin is a three-dimensionally branched aromatic polymer, composed of phenyl propane units, which is susceptible to bioconversion through the growth of the white rot fungus, Pluerotus ostreatus. Processing conditions, that include both a hot water pretreatment and fungal growth and that lead to the facile conversion of plant polysaccharides to glucose, are presented.

Bioconversion of Chitin to Bioactive Chitooligosaccharides: Amelioration and Coastal Pollution Reduction by Microbial Resources.

PubMed

Kumar, Manish; Brar, Amandeep; Vivekanand, V; Pareek, Nidhi

2018-04-10

Chitin-metabolizing products are of high industrial relevance in current scenario due to their wide biological applications, relatively lower cost, greater abundance, and sustainable supply. Chitooligosaccharides have remarkably wide spectrum of applications in therapeutics such as antitumor agents, immunomodulators, drug delivery, gene therapy, wound dressings, as chitinase inhibitors to prevent malaria. Hypocholesterolemic and antimicrobial activities of chitooligosaccharides make them a molecule of choice for food industry, and their functional profile depends on the physicochemical characteristics. Recently, chitin-based nanomaterials are also gaining tremendous importance in biomedical and agricultural applications. Crystallinity and insolubility of chitin imposes a major hurdle in the way of polymer utilization. Chemical production processes are known to produce chitooligosaccharides with variable degree of polymerization and properties along with ecological concerns. Biological production routes mainly involve chitinases, chitosanases, and chitin-binding proteins. Development of bio-catalytic production routes for chitin will not only enhance the production of commercially viable chitooligosaccharides with defined molecular properties but will also provide a means to combat marine pollution with value addition.

Vitamin E in human skin: organ-specific physiology and considerations for its use in dermatology.

PubMed

Thiele, Jens J; Ekanayake-Mudiyanselage, Swarna

2007-01-01

Vitamin E has been used for more than 50 years in experimental and clinical dermatology. While a large number of case reports were published in this time, there is still a lack of controlled clinical studies providing a rationale for well defined dosages and clinical indications. In contrast, advances in basic research on the physiology, mechanism of action, penetration, bioconversion and photoprotection of vitamin E in human skin has led to the development of numerous new formulations for use in cosmetics and skin care products. This article reviews basic mechanisms and possible cosmetic as well as clinical implications of the recent advances in cutaneous vitamin E research. Experimental evidence suggests that topical and oral vitamin E has antitumorigenic, photoprotective, and skin barrier stabilizing properties. While the current use of vitamin E is largely limited to cosmetics, controlled clinical studies for indications such as atopic dermatitis or preventions of photocarcinogenesis are needed to evaluate the clinical benefit of vitamin E.

Associating cooking additives with sodium hydroxide to pretreat bamboo residues for improving the enzymatic saccharification and monosaccharides production.

PubMed

Huang, Caoxing; He, Juan; Wang, Yan; Min, Douyong; Yong, Qiang

2015-10-01

Cooking additive pulping technique is used in kraft mill to increase delignification degree and pulp yield. In this work, cooking additives were firstly applied in the sodium hydroxide pretreatment for improving the bioconversion of bamboo residues to monosaccharides. Meanwhile, steam explosion and sulfuric acid pretreatments were also carried out on the sample to compare their impacts on monosaccharides production. Results indicated that associating anthraquinone with sodium hydroxide pretreatment showed the best performance in improving the original carbohydrates recovery, delignification, enzymatic saccharification, and monosaccharides production. After consecutive pretreatment and enzymatic saccharification process, 347.49 g, 307.48 g, 142.93 g, and 87.15 g of monosaccharides were released from 1000 g dry bamboo residues pretreated by sodium hydroxide associating with anthraquinone, sodium hydroxide, steam explosion and sulfuric acid, respectively. The results suggested that associating cooking additive with sodium hydroxide is an effective pretreatment for bamboo residues to enhance enzymatic saccharification for monosaccharides production. Copyright © 2015 Elsevier Ltd. All rights reserved.

An update on enzymatic cocktails for lignocellulose breakdown.

PubMed

de Mello Lopes, Andreza; Ferreira Filho, Edivaldo Ximenes; de Souza Moreira, Leonora Rios

2018-05-22

Alternative energy sources have received increasing attention in recent years. The possibility of adding value to agricultural wastes, by producing biofuels and other products with economic value from lignocellulosic biomass by enzymatic hydrolysis, has been widely explored. Lignocellulosic biomass, as well as being an abundant residue, is a complex recalcitrant structure that requires a consortium of enzymes for its complete degradation. Pools of enzymes with different specificities acting together usually produce an increase in hydrolysis yield. Enzymatic cocktails have been widely studied due to their potential industrial application for the bioconversion of lignocellulosic biomass. This review presents an overview of enzymes required to degrade the plant cell wall, paying particular attention to the latest advances in enzymatic cocktail production and the main results obtained with cocktails used to degrade a variety of types of biomass, as well as some future perspectives within this field. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Enhanced biological fixation of methane for microbial lipid production by recombinant Methylomicrobium buryatense

DOE PAGES

Fei, Qiang; Puri, Aaron W.; Smith, Holly; ...

2018-05-04

Due to the success of shale gas development in the US, the production cost of natural gas has been reduced significantly, which in turn has made methane (CH 4), the major component of natural gas, a potential alternative substrate for bioconversion processes compared with other high-price raw material sources or edible feedstocks. Therefore, exploring effective ways to use CH 4 for the production of biofuels is attractive. Biological fixation of CH 4 by methanotrophic bacteria capable of using CH 4 as their sole carbon and energy source has obtained great attention for biofuel production from this resource. Here, a fast-growingmore » and lipid-rich methanotroph, Methylomicrobium buryatense 5GB1 and its glycogen-knock-out mutant (AP18) were investigated for the production of lipids derived from intracellular membranes, which are key precursors for the production of green diesel. The effects of culture conditions on cell growth and lipid production were investigated in high cell density cultivation with continuous feeding of CH 4 and O2. The highest dry cell weight observed was 21.4 g/L and the maximum lipid productivity observed was 45.4 mg/L/h obtained in batch cultures, which corresponds to a 2-fold enhancement in cell density and 3-fold improvement in lipid production, compared with previous reported data from cultures of 5GB1. A 90% enhancement of lipid content was achieved by limiting the biosynthesis of glycogen in strain AP18. Increased CH 4/O 2 uptake and CO 2 evaluation rates were observed in AP18 cultures suggesting that more carbon substrate and energy are needed for AP18 growth while producing lipids. The lipid produced by M. buryatense was estimated to have a cetane number of 75, which is 50% higher than biofuel standards requested by US and EU. Cell growth and lipid production were significantly influenced by culture conditions for both 5GB1 and AP18. Enhanced lipid production in terms of titer, productivity, and content was achieved under high cell density culture conditions by blocking glycogen accumulation as a carbon sink in the strain AP18. Differences observed in CH 4/O 2 gas uptake and CO 2 evolution rates as well as cell growth and glycogen accumulation between 5GB1 and AP18 suggest changes in the metabolic network between these strains. This bioconversion process provides a promising opportunity to transform CH 4 into biofuel molecules and encourages further investigation to elucidate the remarkable CH 4 biofixation mechanism used by these bacteria.« less

Enhanced biological fixation of methane for microbial lipid production by recombinant Methylomicrobium buryatense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fei, Qiang; Puri, Aaron W.; Smith, Holly

Due to the success of shale gas development in the US, the production cost of natural gas has been reduced significantly, which in turn has made methane (CH 4), the major component of natural gas, a potential alternative substrate for bioconversion processes compared with other high-price raw material sources or edible feedstocks. Therefore, exploring effective ways to use CH 4 for the production of biofuels is attractive. Biological fixation of CH 4 by methanotrophic bacteria capable of using CH 4 as their sole carbon and energy source has obtained great attention for biofuel production from this resource. Here, a fast-growingmore » and lipid-rich methanotroph, Methylomicrobium buryatense 5GB1 and its glycogen-knock-out mutant (AP18) were investigated for the production of lipids derived from intracellular membranes, which are key precursors for the production of green diesel. The effects of culture conditions on cell growth and lipid production were investigated in high cell density cultivation with continuous feeding of CH 4 and O2. The highest dry cell weight observed was 21.4 g/L and the maximum lipid productivity observed was 45.4 mg/L/h obtained in batch cultures, which corresponds to a 2-fold enhancement in cell density and 3-fold improvement in lipid production, compared with previous reported data from cultures of 5GB1. A 90% enhancement of lipid content was achieved by limiting the biosynthesis of glycogen in strain AP18. Increased CH 4/O 2 uptake and CO 2 evaluation rates were observed in AP18 cultures suggesting that more carbon substrate and energy are needed for AP18 growth while producing lipids. The lipid produced by M. buryatense was estimated to have a cetane number of 75, which is 50% higher than biofuel standards requested by US and EU. Cell growth and lipid production were significantly influenced by culture conditions for both 5GB1 and AP18. Enhanced lipid production in terms of titer, productivity, and content was achieved under high cell density culture conditions by blocking glycogen accumulation as a carbon sink in the strain AP18. Differences observed in CH 4/O 2 gas uptake and CO 2 evolution rates as well as cell growth and glycogen accumulation between 5GB1 and AP18 suggest changes in the metabolic network between these strains. This bioconversion process provides a promising opportunity to transform CH 4 into biofuel molecules and encourages further investigation to elucidate the remarkable CH 4 biofixation mechanism used by these bacteria.« less

Enhanced biological fixation of methane for microbial lipid production by recombinant Methylomicrobium buryatense.

PubMed

Fei, Qiang; Puri, Aaron W; Smith, Holly; Dowe, Nancy; Pienkos, Philip T

2018-01-01

Due to the success of shale gas development in the US, the production cost of natural gas has been reduced significantly, which in turn has made methane (CH 4 ), the major component of natural gas, a potential alternative substrate for bioconversion processes compared with other high-price raw material sources or edible feedstocks. Therefore, exploring effective ways to use CH 4 for the production of biofuels is attractive. Biological fixation of CH 4 by methanotrophic bacteria capable of using CH 4 as their sole carbon and energy source has obtained great attention for biofuel production from this resource. In this study, a fast-growing and lipid-rich methanotroph , Methylomicrobium buryatense 5GB1 and its glycogen-knock-out mutant (AP18) were investigated for the production of lipids derived from intracellular membranes, which are key precursors for the production of green diesel. The effects of culture conditions on cell growth and lipid production were investigated in high cell density cultivation with continuous feeding of CH 4 and O 2 . The highest dry cell weight observed was 21.4 g/L and the maximum lipid productivity observed was 45.4 mg/L/h obtained in batch cultures, which corresponds to a 2-fold enhancement in cell density and 3-fold improvement in lipid production, compared with previous reported data from cultures of 5GB1. A 90% enhancement of lipid content was achieved by limiting the biosynthesis of glycogen in strain AP18. Increased CH 4 /O 2 uptake and CO 2 evaluation rates were observed in AP18 cultures suggesting that more carbon substrate and energy are needed for AP18 growth while producing lipids. The lipid produced by M. buryatense was estimated to have a cetane number of 75, which is 50% higher than biofuel standards requested by US and EU. Cell growth and lipid production were significantly influenced by culture conditions for both 5GB1 and AP18. Enhanced lipid production in terms of titer, productivity, and content was achieved under high cell density culture conditions by blocking glycogen accumulation as a carbon sink in the strain AP18. Differences observed in CH 4 /O 2 gas uptake and CO 2 evolution rates as well as cell growth and glycogen accumulation between 5GB1 and AP18 suggest changes in the metabolic network between these strains. This bioconversion process provides a promising opportunity to transform CH 4 into biofuel molecules and encourages further investigation to elucidate the remarkable CH 4 biofixation mechanism used by these bacteria.

Sequestration of carbon dioxide and production of biomolecules using cyanobacteria.

PubMed

Upendar, Ganta; Singh, Sunita; Chakrabarty, Jitamanyu; Chandra Ghanta, Kartik; Dutta, Susmita; Dutta, Abhishek

2018-07-15

A cyanobacterial strain, Synechococcus sp. NIT18, has been applied to sequester CO 2 using sodium carbonate as inorganic carbon source due to its efficiency of CO 2 bioconversion and high biomass production. The biomass obtained is used for the extraction of biomolecules - protein, carbohydrate and lipid. The main objective of the study is to maximize the biomass and biomolecules production with CO 2 sequestration using cyanobacterial strain cultivated under different concentrations of CO 2 (5-20%), pH (7-11) and inoculum size (5-12.5%) within a statistical framework. Maximum sequestration of CO 2 and maximum productivities of protein, carbohydrate and lipid are 71.02%, 4.9 mg/L/day, 6.7 mg/L/day and 1.6 mg/L/day respectively, at initial CO 2 concentration: 10%, pH: 9 and inoculum size: 12.5%. Since flue gas contains 10-15% CO 2 and the present strain is able to sequester CO 2 in this range, the strain could be considered as a useful tool for CO 2 mitigation for greener world. Copyright © 2018 Elsevier Ltd. All rights reserved.

Vascular plants for water pollution control and renewable sources of energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolverton, B.C.; McDonald, R.C.

1980-01-01

Vascular aquatic plants have demonstrated their ability to remove pollutants from domestic and chemical wastewaters. Plants such as the water hyacinth (Eichhornia crassipes), duckweed (Lemna sp., Spirodela sp., and Wolffia sp.), and cattail (Typha sp.) thrive in nutrient-rich waters and produce tremendous quantities of biomass under favorable climatic conditions. This method of wastewater treatment is currently being used exclusively at NASA's National Space Technology Laboratories (NSTL) with water hyacinths and duckweed to treat daily over 759 m/sup 3/ of domestic wastewater and 114 m/sup 3/ of chemical wastewater in four separate systems. The harvested plants from these systems have beenmore » used in various biomass utilization projects over the past five years. In laboratory batch studies of digesting vascular plants with anaerobic filters, NASA has found that 140 to 280 liters methane per kg dry weight can be obtained in an average of 23 days. Current NASA projects at NSTL seek to expand the technology required to design energy systems which produce methane through bioconversion with anaerobic filters and use the mineral residue as a nutrient source for producing new biomass.« less

Bioconversion of renewable resources into lactic acid: an industrial view.

PubMed

Yadav, A K; Chaudhari, A B; Kothari, R M

2011-03-01

Lactic acid, an anaerobic product of glycolysis, can be theoretically produced by synthetic route; however, it is commercially produced by homo-fermentative batch mode of operations. Factors affecting its production and strategies improving it are considered while devising an optimized protocol. Although a hetero-fermentative mode of production exists, it is rarely used for commercial production. Attempts to use Rhizopus sp. for lactic acid production through either hetero-fermentative or thermophilic conditions were not economical. Since almost 70% of the cost of its production is accounted by raw materials, R & D efforts are still focused to find economically attractive agri-products to serve as sources of carbon and complex nitrogen inputs to meet fastidious nutrient needs for microbial growth and lactic acid production. Therefore, need exists for using multi-pronged strategies for higher productivity. Its present production and consumption scenario is examined. Its optically active isomers and chemical structure permit its use for the production of several industrially important chemicals, health products (probiotics), food preservatives, and bio-plastics. In addition, its salts and esters appear to have a variety of applications.

Transgenic switchgrass ( Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: A two-year comparative analysis of field-grown lines modified for target gene or genetic element expression

DOE PAGES

Dumitrache, Alexandru; Natzke, Jace; Rodriguez, Jr., Miguel; ...

2016-11-18

Five different types of transgenic ( GAUT4, miRNA, MYB4, COMT and FPGS) Panicum virgatum L. (switchgrass) were grown in a field in Knoxville, Tenn., USA over two consecutive years between 2011 and 2015 in separate experiments. Clonal replicates were established (year-one) and produced much greater biomass during the second year. After each growing season the above ground biomass was analyzed for cell wall sugars and for recalcitrance to enzymatic digestibility, and biofuel using a separate hydrolysis and fermentation (SHF) screen. Here, each transgenic event and control had more glucan, xylan and less ethanol (g/g basis) from the second year ofmore » growth relative to the first year plants. There was no correlation between plant carbohydrate content and biofuel production. In each of cell wall-targeted transgenics, GAUT4, MYB4, COMT and FPGS, the second year of growth resulted in increased carbohydrate abundance (up to 12%) and reduced recalcitrance through higher ethanol yields (up to 21%) over the non-transgenic control plants.« less

Conversion of corn stover alkaline pre-treatment waste streams into biodiesel via Rhodococci

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le, Rosemary K.; Wells Jr., Tyrone; Das, Parthapratim

We present the bioconversion of second-generation cellulosic ethanol waste streams into biodiesel via oleaginous bacteria is a novel optimization strategy for biorefineries with substantial potential for rapid development. In this study, one- and two-stage alkali/alkali-peroxide pretreatment waste streams of corn stover were separately implemented as feedstocks in 96 h batch reactor fermentations with wild-type Rhodococcus opacus PD 630, R. opacus DSM 1069, and R. jostii DSM 44719 T . Here we show using 31P-NMR, HPAECPAD, and SEC analyses, that the more rigorous and chemically-efficient two-stage chemical pretreatment effluent provided higher concentrations of solubilized glucose and lower molecular weight (70 300more » g mol1 ) lignin degradation products thereby enabling improved cellular density, viability, and oleaginicity in each respective strain. The most significant yields were by R. opacus PD 630, which converted 6.2% of organic content with a maximal total lipid production of 1.3 g L1 and accumulated 42.1% in oils based on cell dry weight after 48 h.« less

Production of Basidiomata and Ligninolytic Enzymes by the Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), in Licuri (Syagrus coronata) Wastes in Brazil.

PubMed

de Menezes, Thais Almeida; Bispo, Aline Simoes da Rocha; Koblitz, Maria Gabriela Bello; Vandenberghe, Luciana Porto de Souza; Kamida, Helio Mitoshi; Goes-Neto, Aristoteles

2016-01-01

Ganoderma lucidum is a medicinal mushroom with different forms of bioactivity that has been used in popular medicine for centuries. This study aimed to test the application of agricultural wastes (fruit shells, leaves, and bracts) from the endemic Brazilian palm tree Syagrus coronata (licuri) as substrates for the production of G. lucidum basidiomata and ligninolytic enzymes via solid-state fermentation. The best culture conditions were the same for all substrates (pH 6.5, carbon-to-nitrogen ratio = 40, and temperature 30°C) and were established from preliminary assays. The yield was not significantly different for bracts (33.53 g/kg) and leaves (37.48 g/kg), nor for the biological efficiency in these same substrates: bracts, 3.35%; leaves, 3.75%. The highest laccase (13.80 U/L) and manganese peroxidase (14.92 U/L) activities were achieved after 14 and 28 days of incubation, respectively, using bracts as the substrate. Licuri residues are then potential substrates to be used in the bioconversion process for mycelia, basidiomata, and ligninolytic enzyme production by G. lucidum.

Self-adaption of methane-producing communities to pH disturbance at different acetate concentrations by shifting pathways and population interaction.

PubMed

Hao, Liping; Lü, Fan; Li, Lei; Wu, Qing; Shao, Liming; He, Pinjing

2013-07-01

To investigate the competition among acetate-utilizing microorganisms at different acetate levels, bioconversion processes of 50, 100, 150 and 200 mM acetate in the presence and absence of methanogenic inhibitor CH3F were monitored in thermophilic methanogenic system. The successive response of methane-producing community during the deteriorative and recovery phases caused by pH disturbance was analyzed. High acetate concentration (>50mM) inhibited the activity of acetoclastic methanogenesis (AM). The increasing pH (>7.5) enhanced this inhibition. The syntrophic acetate oxidizing (SAO) bacteria and hydrogenotrophic methanogens including Methanomicrobiales and Methanobacteirales were more tolerant to the stress from high acetate concentration and high pH. Resumption from alkali condition to normal pH stimulated the growth of acetate oxidizing syntrophs. The reaction rate of SAO-HM was lower than that of AM. These results point to the possibility to regenerate the deteriorated anaerobic digesters by addition of acclimatized inocula rich in acetate-oxidizing syntrophs. Copyright © 2013 Elsevier Ltd. All rights reserved.

Valorization of Cheese and Tofu Whey through Enzymatic Synthesis of Lactosucrose.

PubMed

Corzo-Martinez, Marta; Luscher, Alice; de Las Rivas, Blanca; Muñoz, Rosario; Moreno, F Javier

2015-01-01

This work deals with the development of a new bioprocess for the efficient synthesis of lactosucrose, a potential prebiotic oligosaccharide with a high value-added, from two important and inexpensive agro-industrial by-products such as tofu whey and cheese whey permeate. The bioconversion is driven by the ability of the enzyme levansucrase SacB from Bacillus subtilis CECT 39 to transfructosylate lactose contained in the cheese whey permeate by using not only sucrose but also raffinose and stachyose, which are present in considerable amounts in the tofu whey, as suitable donors of fructosyl moieties. The maximum lactosucrose concentration obtained from both by-products was 80.1 g L-1 after a short reaction time 120 min at 37°C, leading to productivity and specific productivity values of 40.1 g lactosucrose L-1 h-1 and 80.1 mg lactosucrose U enzyme-1 h-1, respectively. Findings contained in this work could provide a new strategy to valorize agro-industrial by-products as cheese whey permeate and, specially, tofu whey by means of their use as renewable resources in the enzymatic synthesis of bioactive oligosaccharides.

Effectiveness of the Novel Herbal Medicine, KIOM-MA, and Its Bioconversion Product, KIOM-MA128, on the Treatment of Atopic Dermatitis.

PubMed

Chung, Tae Ho; Kang, Tae Jin; Cho, Won-Kyung; Im, Ga Young; Lee, Geum Seon; Yang, Min Cheol; Cho, Chang-Won; Ma, Jin Yeul

2012-01-01

This study was conducted to determine if oral administration of the novel herbal medicine, KIOM-MA, and its Lactobacillus acidophilus-fermented product, KIOM-MA128, has therapeutic properties for the treatment of atopic dermatitis (AD). Using AD-induced BALB/c mice by Ovalbumin and aluminum hydroxide, the effectiveness of KIOM-MA and KIOM-MA128 on AD was evaluated. Oral administration of KIOM-MA and KIOM-MA128 reduced major clinical signs of AD including erythema/darkening, edema/papulation, excoriations, lichenification/prurigo, and dryness. Interestingly, KIOM-MA128 more significantly improved AD-related symptoms including decrease of IgE level in the plasma as well as reduction of scratching behavior, skin severity in the AD BALB/c model. HPLC analysis showed the significant changes in the constituent patterns between KIOM-MA and KIOM-MA128. Our results suggest that both KIOM-MA and KIOM-MA128 have potential for therapeutic reagent for the treatment of AD, and further, the efficacy is significantly enhanced by L. acidophilus fermentation via increases in its indicator molecule.

Comparative and Functional Genomics of Rhodococcus opacus PD630 for Biofuels Development

PubMed Central

Holder, Jason W.; Ulrich, Jil C.; DeBono, Anthony C.; Godfrey, Paul A.; Desjardins, Christopher A.; Zucker, Jeremy; Zeng, Qiandong; Leach, Alex L. B.; Ghiviriga, Ion; Dancel, Christine; Abeel, Thomas; Gevers, Dirk; Kodira, Chinnappa D.; Desany, Brian; Affourtit, Jason P.; Birren, Bruce W.; Sinskey, Anthony J.

2011-01-01

The Actinomycetales bacteria Rhodococcus opacus PD630 and Rhodococcus jostii RHA1 bioconvert a diverse range of organic substrates through lipid biosynthesis into large quantities of energy-rich triacylglycerols (TAGs). To describe the genetic basis of the Rhodococcus oleaginous metabolism, we sequenced and performed comparative analysis of the 9.27 Mb R. opacus PD630 genome. Metabolic-reconstruction assigned 2017 enzymatic reactions to the 8632 R. opacus PD630 genes we identified. Of these, 261 genes were implicated in the R. opacus PD630 TAGs cycle by metabolic reconstruction and gene family analysis. Rhodococcus synthesizes uncommon straight-chain odd-carbon fatty acids in high abundance and stores them as TAGs. We have identified these to be pentadecanoic, heptadecanoic, and cis-heptadecenoic acids. To identify bioconversion pathways, we screened R. opacus PD630, R. jostii RHA1, Ralstonia eutropha H16, and C. glutamicum 13032 for growth on 190 compounds. The results of the catabolic screen, phylogenetic analysis of the TAGs cycle enzymes, and metabolic product characterizations were integrated into a working model of prokaryotic oleaginy. PMID:21931557

Pathways for degradation of lignin in bacteria and fungi.

PubMed

Bugg, Timothy D H; Ahmad, Mark; Hardiman, Elizabeth M; Rahmanpour, Rahman

2011-11-01

Lignin is a heterogeneous aromatic polymer found as 10-35% of lignocellulose, found in plant cell walls. The bio-conversion of plant lignocellulose to glucose is an important part of second generation biofuel production, but the resistance of lignin to breakdown is a major obstacle in this process, hence there is considerable interest in the microbial breakdown of lignin. White-rot fungi are known to break down lignin with the aid of extracellular peroxidase and laccase enzymes. There are also reports of bacteria that can degrade lignin, and recent work indicates that bacterial lignin breakdown may be more significant than previously thought. The review will discuss the enzymes for lignin breakdown in fungi and bacteria, and the catabolic pathways for breakdown of the β-aryl ether, biphenyl and other components of lignin in bacteria and fungi. The review will also discuss small molecule phenolic breakdown products from lignin that have been identified from lignin-degrading microbes, and includes a bioinformatic analysis of the occurrence of known lignin-degradation pathways in Gram-positive and Gram-negative bacteria.

Biological conversion of the aqueous wastes from hydrothermal liquefaction of algae and pine wood by Rhodococci

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Yucai; Li, Xiaolu; Xue, Xiaoyun

In this study, R. opacus PD630, R. jostii RHA1, R. jostii RHA1 VanA-, and their co-culture were employed to convert hydrothermal liquefaction aqueous waste (HTLAW) into lipids. After 11 days, the COD reduction of algal-HTLAW reached 93.4% and 92.7% by R. jostii RHA1 and its mutant VanA-, respectively. Woody-HTLAW promoted lipid accumulation of 0.43 g lipid/g cell dry weight in R. opacus PD630 cells. Additionally, the total number of chemicals in HTLAW decreased by over 1/3 after 7 days of coculture, and 0.10 g/L and 0.46 g/L lipids were incrementally accumulated in the cellular mass during the fermentation of wood-more » and algal-HTLAW, respectively. The GC-MS data supported that different metabolism pathways were followed when these Rhodococci strains degraded algae- and woody-HTLAW. These results indicated promising potential of bioconversion of under-utilized carbon and toxic compounds in HTLAW into useful products by selected Rhodococci.« less

Effectiveness of the Novel Herbal Medicine, KIOM-MA, and Its Bioconversion Product, KIOM-MA128, on the Treatment of Atopic Dermatitis

PubMed Central

Chung, Tae Ho; Kang, Tae Jin; Cho, Won-Kyung; Im, Ga Young; Lee, Geum Seon; Yang, Min Cheol; Cho, Chang-Won; Ma, Jin Yeul

2012-01-01

This study was conducted to determine if oral administration of the novel herbal medicine, KIOM-MA, and its Lactobacillus acidophilus-fermented product, KIOM-MA128, has therapeutic properties for the treatment of atopic dermatitis (AD). Using AD-induced BALB/c mice by Ovalbumin and aluminum hydroxide, the effectiveness of KIOM-MA and KIOM-MA128 on AD was evaluated. Oral administration of KIOM-MA and KIOM-MA128 reduced major clinical signs of AD including erythema/darkening, edema/papulation, excoriations, lichenification/prurigo, and dryness. Interestingly, KIOM-MA128 more significantly improved AD-related symptoms including decrease of IgE level in the plasma as well as reduction of scratching behavior, skin severity in the AD BALB/c model. HPLC analysis showed the significant changes in the constituent patterns between KIOM-MA and KIOM-MA128. Our results suggest that both KIOM-MA and KIOM-MA128 have potential for therapeutic reagent for the treatment of AD, and further, the efficacy is significantly enhanced by L. acidophilus fermentation via increases in its indicator molecule. PMID:22454683

Identification of a Saccharomyces cerevisiae glucosidase that hydrolyzes flavonoid glucosides.

PubMed

Schmidt, Sabine; Rainieri, Sandra; Witte, Simone; Matern, Ulrich; Martens, Stefan

2011-03-01

Baker's yeast (Saccharomyces cerevisiae) whole-cell bioconversions of naringenin 7-O-β-glucoside revealed considerable β-glucosidase activity, which impairs any strategy to generate or modify flavonoid glucosides in yeast transformants. Up to 10 putative glycoside hydrolases annotated in the S. cerevisiae genome database were overexpressed with His tags in yeast cells. Examination of these recombinant, partially purified polypeptides for hydrolytic activity with synthetic chromogenic α- or β-glucosides identified three efficient β-glucosidases (EXG1, SPR1, and YIR007W), which were further assayed with natural flavonoid β-glucoside substrates and product verification by thin-layer chromatography (TLC) or high-performance liquid chromatography (HPLC). Preferential hydrolysis of 7- or 4'-O-glucosides of isoflavones, flavonols, flavones, and flavanones was observed in vitro with all three glucosidases, while anthocyanins were also accepted as substrates. The glucosidase activities of EXG1 and SPR1 were completely abolished by Val168Tyr mutation, which confirmed the relevance of this residue, as reported for other glucosidases. Most importantly, biotransformation experiments with knockout yeast strains revealed that only EXG1 knockout strains lost the capability to hydrolyze flavonoid glucosides.

Uptake and metabolism of fluorescent steroids by mycobacterial cells.

PubMed

Faletrov, Yaroslav; Brzostek, Anna; Plocinska, Renata; Dziadek, Jarosław; Rudaya, Elena; Edimecheva, Irina; Shkumatov, Vladimir

2017-01-01

Fluorescent steroids BODIPY-cholesterol (BPCh) and 7-nitrobenzoxadiazole-4-amino-(NBD)-labeled 22-NBD-chelesterol (22NC) as well as synthesized 20-(NBD)-pregn-5-en-3β-ol (20NP) were found to undergo bioconversions by Mycobacterium tuberculosis H 37 Rv and M. smegmatis mc 2 155. The major fluorescent products were determined to be 4-en-3-one derivatives of the compounds. Degradation of NBD fluorophore was also detected in the cases of 22NC and 20NP, but neither NBD degradation nor steroidal part modification were observed for the synthesized 3-(NBD)-cholestane. Mycobacterial 3β-hydroxysteroid dehydrogenases were concluded to be responsible for the formation of the 4-en-3-one derivatives. All the compounds tested were found to cause staining both membrane lipids and cytosolic lipid droplets when incubated with mycobacteria in different manner, demonstrating ability of the steroids to reside in the compartments. The findings reveal a potential of the compounds for monitoring of steroid interactions with mycobacteria and provide information for design of new probes for this purpose. Copyright © 2016 Elsevier Inc. All rights reserved.

Hemicellulosic ethanol production by immobilized cells of Scheffersomyces stipitis: Effect of cell concentration and stirring

PubMed Central

Milessi, Thais S S; Antunes, Felipe A F; Chandel, Anuj K; da Silva, Silvio S

2015-01-01

Bioconversion of hemicellulosic hydrolysate into ethanol plays a pivotal role in the overall success of biorefineries. For the efficient fermentative conversion of hemicellulosic hydrolysates into ethanol, the use of immobilized cells system could provide the enhanced ethanol productivities with significant time savings. Here, we investigated the effect of 2 important factors (e.g., cell concentration and stirring) on ethanol production from sugarcane bagasse hydrolysate using the yeast Scheffersomyces stipitis immobilized in calcium alginate matrix. A 22 full factorial design of experiment was performed considering the process variables- immobilized cell concentration (3.0, 6.5 and 10.0 g/L) and stirring (100, 200 and 300 rpm). Statistical analysis showed that stirring has the major influence on ethanol production. Maximum ethanol production (8.90 g/l) with ethanol yield (Yp/s) of 0.33 g/g and ethanol productivity (Qp) of 0.185 g/l/h was obtained under the optimized process conditions (10.0 g/L of cells and 100 rpm). PMID:25488725

Enhanced enzymatic hydrolysis and acetone-butanol-ethanol fermentation of sugarcane bagasse by combined diluted acid with oxidate ammonolysis pretreatment.

PubMed

Li, Hailong; Xiong, Lian; Chen, Xuefang; Wang, Can; Qi, Gaoxiang; Huang, Chao; Luo, Mutan; Chen, Xinde

2017-03-01

This study aims to propose a biorefinery pretreatment technology for the bioconversion of sugarcane bagasse (SB) into biofuels and N-fertilizers. Performance of diluted acid (DA), aqueous ammonia (AA), oxidate ammonolysis (OA) and the combined DA with AA or OA were compared in SB pretreatment by enzymatic hydrolysis, structural characterization and acetone-butanol-ethanol (ABE) fermentation. Results indicated that DA-OA pretreatment improves the digestibility of SB by sufficiently hydrolyzing hemicellulose into fermentable monosaccharides and oxidating lignin into soluble N-fertilizer with high nitrogen content (11.25%) and low C/N ratio (3.39). The enzymatic hydrolysates from DA-OA pretreated SB mainly composed of glucose was more suitable for the production of ABE solvents than the enzymatic hydrolysates from OA pretreated SB containing high ratio of xylose. The fermentation of enzymatic hydrolysates from DA-OA pretreated SB produced 12.12g/L ABE in 120h. These results suggested that SB could be utilized efficient, economic, and environmental by DA-OA pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional diversity of carbohydrate-active enzymes enabling a bacterium to ferment plant biomass.

PubMed

Boutard, Magali; Cerisy, Tristan; Nogue, Pierre-Yves; Alberti, Adriana; Weissenbach, Jean; Salanoubat, Marcel; Tolonen, Andrew C

2014-11-01

Microbial metabolism of plant polysaccharides is an important part of environmental carbon cycling, human nutrition, and industrial processes based on cellulosic bioconversion. Here we demonstrate a broadly applicable method to analyze how microbes catabolize plant polysaccharides that integrates carbohydrate-active enzyme (CAZyme) assays, RNA sequencing (RNA-seq), and anaerobic growth screening. We apply this method to study how the bacterium Clostridium phytofermentans ferments plant biomass components including glucans, mannans, xylans, galactans, pectins, and arabinans. These polysaccharides are fermented with variable efficiencies, and diauxies prioritize metabolism of preferred substrates. Strand-specific RNA-seq reveals how this bacterium responds to polysaccharides by up-regulating specific groups of CAZymes, transporters, and enzymes to metabolize the constituent sugars. Fifty-six up-regulated CAZymes were purified, and their activities show most polysaccharides are degraded by multiple enzymes, often from the same family, but with divergent rates, specificities, and cellular localizations. CAZymes were then tested in combination to identify synergies between enzymes acting on the same substrate with different catalytic mechanisms. We discuss how these results advance our understanding of how microbes degrade and metabolize plant biomass.

Bioconversion of shrimp waste Penaeus merguiensis using lactic acid fermentation: An alternative procedure for chemical extraction of chitin and chitosan.

PubMed

Sedaghat, Fatemeh; Yousefzadi, Morteza; Toiserkani, Hojjat; Najafipour, Sohrab

2017-11-01

Chitin extraction from shrimp wastes by biological treatment, using the Pseudomonas aeruginosa was a positive and simple method. In order to look for the optimal conditions, the wastes were incubated at 30°C and 100rpm in different glucose (0%, 10%, 15% and 20%) and inoculation (10%, 15% and 20%) concentrations for 4 and 6days. At the end of fermentation, Protease activity was investigated at different temperatures and temperature 50°C was considered as the optimum. The results obtained also showed a direct relationship between the concentration of different parameters and deproteinization and demineralization rates, so that the optimal conditions were 20% glucose, 20% inoculation and 6days fermentation. These conditions led to 82% demineralization, 92% deproteinization and chitin yield of 47%. Then, chitin was converted to chitosan using microwave, autoclave and traditional methods. The highest yield (87%) was obtained with autoclave method. At the end, the chitin and chitosan were characterized by elemental analysis and FTIR. Copyright © 2017 Elsevier B.V. All rights reserved.

Microalgae as a feedstock for biofuel precursors and value-added products: Green fuels and golden opportunities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Yuting; Rosenberg, Julian N.; Bohutskyi, Pavlo

In this study, the prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO 2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids,more » one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.« less

Production of D-tagatose, a low caloric sweetener during milk fermentation using L-arabinose isomerase.

PubMed

Rhimi, Moez; Chouayekh, Hichem; Gouillouard, Isabelle; Maguin, Emmanuelle; Bejar, Samir

2011-02-01

Lactobacillusdelbrueckii subsp. bulgaricus and Streptococcus thermophilus are used for the biotransformation of milk in yoghurt. During milk fermentation, these lactic acid bacteria (LAB) hydrolyze lactose producing a glucose moiety that is further metabolized and a galactose moiety that they are enable to metabolize. We investigated the ability of L. bulgaricus and S. thermophilus strains expressing a heterologous L-arabinose isomerase to convert residual D-galactose to D-tagatose. The Bacillus stearothermophilus US100l-arabinose isomerase (US100l-AI) was expressed in both LAB, using a new shuttle vector where the araA US100 gene is under the control of the strong and constitutive promoter of the L. bulgaricus ATCC 11842 hlbA gene. The production of L-AI by these LAB allowed the bioconversion of D-galactose to D-tagatose during fermentation in laboratory media and milk. We also established that the addition of L-AI to milk also allowed the conversion of D-galactose into D-tagatose during the fermentation process. Copyright © 2010 Elsevier Ltd. All rights reserved.

Antioxidant properties of different edible mushroom species and increased bioconversion efficiency of Pleurotus eryngii using locally available casing materials.

PubMed

Mishra, K K; Pal, R S; Arunkumar, R; Chandrashekara, C; Jain, S K; Bhatt, J C

2013-06-01

Total phenolics, radical scavenging activity (RSA) on DPPH, ascorbic acid content and chelating activity on Fe(2+) of Pleurotus citrinopileatus, Pleurotus djamor, Pleurotus eryngii, Pleurotus flabellatus, Pleurotus florida, Pleurotus ostreatus, Pleurotus sajor-caju and Hypsizygus ulmarius have been evaluated. The assayed mushrooms contained 3.94-21.67 mg TAE of phenolics, 13.63-69.67% DPPH scavenging activity, 3.76-6.76 mg ascorbic acid and 60.25-82.7% chelating activity. Principal Component Analysis (PCA) revealed that significantly higher total phenolics, RSA on DPPH and growth/day was present in P. eryngii whereas P. citrinopileatus showed higher ascorbic acid and chelating activity. Agglomerative hierarchical clustering analysis revealed that studied mushroom species fall into two clusters; Cluster I included P. djamor, P. eryngii and P. flabellatus, while Cluster II included H. ulmarius, P. sajor-caju, P. citrinopileatus, P. ostreatus and P. florida. Enhanced yield of P. eryngii was achieved on spent compost casing material. Use of casing materials enhanced yield by 21-107% over non-cased substrate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase

DOE PAGES

Wang, Jun; Liu, Xi; Wang, Xu -Dong; ...

2016-08-18

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7 °C) and decrease ofmore » crystallizing point (3 °C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from 212.3 to 14.6 per batch with the microreactor. Altogether, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts.« less

How to Establish a Bioregenerative Life Support System for Long-Term Crewed Missions to the Moon or Mars.

PubMed

Fu, Yuming; Li, Leyuan; Xie, Beizhen; Dong, Chen; Wang, Mingjuan; Jia, Boyang; Shao, Lingzhi; Dong, Yingying; Deng, Shengda; Liu, Hui; Liu, Guanghui; Liu, Bojie; Hu, Dawei; Liu, Hong

2016-12-01

To conduct crewed simulation experiments of bioregenerative life support systems on the ground is a critical step for human life support in deep-space exploration. An artificial closed ecosystem named Lunar Palace 1 was built through integrating efficient higher plant cultivation, animal protein production, urine nitrogen recycling, and bioconversion of solid waste. Subsequently, a 105-day, multicrew, closed integrative bioregenerative life support systems experiment in Lunar Palace 1 was carried out from February through May 2014. The results show that environmental conditions as well as the gas balance between O 2 and CO 2 in the system were well maintained during the 105-day experiment. A total of 21 plant species in this system kept a harmonious coexistent relationship, and 20.5% nitrogen recovery from urine, 41% solid waste degradation, and a small amount of insect in situ production were achieved. During the 105-day experiment, oxygen and water were recycled, and 55% of the food was regenerated. Key Words: Bioregenerative life support systems (BLSS)-Space agriculture-Space life support-Waste recycle-Water recycle. Astrobiology 16, 925-936.

Destination bioeconomy - The path towards a smarter, more sustainable future.

PubMed

Dupont-Inglis, Joanna; Borg, Agnes

2018-01-25

Five years following the publication of the EU Bioeconomy Strategy, this article discusses the state of play of the bioeconomy in Europe. Placing specific focus on Industrial Biotech, it outlines ten pragmatic recommendations from BIO-TIC [BIO-TIC, A roadmap to a thriving industrial biotechnology sector in Europe, 2015], an EU FP7 funded project completed in 2015 and coordinated by EuropaBio, comprehensively examining the hurdles to the development of a bioeconomy in Europe, enabled by industrial biotech. These include improving opportunities for feedstock producers within the bioeconomy; investigating the scope for using novel biomass; developing a workforce which can maintain Europe's competitiveness in industrial biotechnology; introducing a long-term, stable and transparent policy and incentive framework to promote the bioeconomy; improving public perception and awareness of industrial biotechnology and bio-based products; identifying, leveraging and building upon EU capabilities for pilot and demonstration facilities; promoting the use of co-products from processing; improving the bioconversion and downstream processing steps; improving access to financing for large-scale biorefinery projects; developing stronger relationships between conventional and non-conventional players. Copyright © 2017. Published by Elsevier B.V.

Microalgae as a feedstock for biofuel precursors and value-added products: Green fuels and golden opportunities

DOE PAGES

Tang, Yuting; Rosenberg, Julian N.; Bohutskyi, Pavlo; ...

2015-11-16

In this study, the prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO 2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids,more » one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.« less

Improved Xylitol Production from D-Arabitol by Enhancing the Coenzyme Regeneration Efficiency of the Pentose Phosphate Pathway in Gluconobacter oxydans.

PubMed

Li, Sha; Zhang, Jinliang; Xu, Hong; Feng, Xiaohai

2016-02-10

Gluconobacter oxydans is used to produce xylitol from D-arabitol. This study aims to improve xylitol production by increasing the coenzyme regeneration efficiency of the pentose phosphate pathway in G. oxydans. Glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were overexpressed in G. oxydans. Real-time PCR and enzyme activity assays revealed that G6PDH/6PGDH activity and coenzyme regeneration efficiency increased in the recombinant G. oxydans strains. Approximately 29.3 g/L xylitol was obtained, with a yield of 73.2%, from 40 g/L d-arabitol in the batch biotransformation with the G. oxydans PZ strain. Moreover, the xylitol productivity (0.62 g/L/h) was 3.26-fold of the wild type strain (0.19 g/L/h). In repetitive batch biotransformation, the G. oxydans PZ cells were used for five cycles without incurring a significant loss in productivity. These results indicate that the recombinant G. oxydans PZ strain is economically feasible for xylitol production in industrial bioconversion.

Biotransformation of furfural and 5-hydroxymethyl furfural (HMF) by Clostridium acetobutylicum ATCC 824 during butanol fermentation.

PubMed

Zhang, Yan; Han, Bei; Ezeji, Thaddeus Chukwuemeka

2012-02-15

The ability of fermenting microorganisms to tolerate furan aldehyde inhibitors (furfural and 5-hydroxymethyl furfural (HMF)) will enhance efficient bioconversion of lignocellulosic biomass hydrolysates to fuels and chemicals. The effect of furfural and HMF on butanol production by Clostridium acetobutylicum 824 was investigated. Whereas specific growth rates, μ, of C. acetobutylicum in the presence of furfural and HMF were in the range of 15-85% and 23-78%, respectively, of the uninhibited Control, μ increased by 8-15% and 23-38% following exhaustion of furfural and HMF in the bioreactor. Using high performance liquid chromatography and spectrophotometric assays, batch fermentations revealed that furfural and HMF were converted to furfuryl alcohol and 2,5-bis-hydroxymethylfuran, respectively, with specific conversion rates of 2.13g furfural and 0.50g HMF per g (biomass) per hour, by exponentially growing C. acetobutylicum. Biotransformation of these furans to lesser inhibitory compounds by C. acetobutylicum will probably enhance overall fermentation of lignocellulosic hydrolysates to butanol. Copyright © 2011 Elsevier B.V. All rights reserved.

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jun; Liu, Xi; Wang, Xu -Dong

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7 °C) and decrease ofmore » crystallizing point (3 °C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from 212.3 to 14.6 per batch with the microreactor. Altogether, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts.« less

Transgenic switchgrass ( Panicum virgatum L.) targeted for reduced recalcitrance to bioconversion: A two-year comparative analysis of field-grown lines modified for target gene or genetic element expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dumitrache, Alexandru; Natzke, Jace; Rodriguez, Jr., Miguel

Five different types of transgenic ( GAUT4, miRNA, MYB4, COMT and FPGS) Panicum virgatum L. (switchgrass) were grown in a field in Knoxville, Tenn., USA over two consecutive years between 2011 and 2015 in separate experiments. Clonal replicates were established (year-one) and produced much greater biomass during the second year. After each growing season the above ground biomass was analyzed for cell wall sugars and for recalcitrance to enzymatic digestibility, and biofuel using a separate hydrolysis and fermentation (SHF) screen. Here, each transgenic event and control had more glucan, xylan and less ethanol (g/g basis) from the second year ofmore » growth relative to the first year plants. There was no correlation between plant carbohydrate content and biofuel production. In each of cell wall-targeted transgenics, GAUT4, MYB4, COMT and FPGS, the second year of growth resulted in increased carbohydrate abundance (up to 12%) and reduced recalcitrance through higher ethanol yields (up to 21%) over the non-transgenic control plants.« less

Consolidated bioprocessing of transgenic switchgrass by an engineered and evolved Clostridium thermocellum strain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yee, Kelsey L; Rodriguez Jr, Miguel; Thompson, Olivia A

Background: Switchgrass is an abundant and dedicated bioenergy feedstock however its inherent recalcitrance is one of the economic hurdles for producing biofuels. The down-regulation of the caffeic acid O-methyl transferase (COMT) gene in the lignin pathway of switchgrass reduced lignin content and S/G ratio, and the transgenic lines showed improved fermentation yield with S. cerevisiae and C. thermocellum (ATCC 27405) in comparison to the wild-type switchgrass. Results: Here we examine the fermentation potential of the COMT transgenic switchgrass and its wild-type line, with an engineered and evolved Clostridium thermocellum (M1570) strain. The fermentation of the transgenic switchgrass had superior conversionmore » relative to the control line with an increase of 20% and ethanol was the primary metabolite accounting for 90% of the total metabolites measured by HPLC. Conclusions: The down-regulation of the COMT gene in switchgrass reduced recalcitrance and improved microbial bioconversion yield. Moreover, these results showed ethanol as the main fermentation metabolite produced by an engineered and evolved C. thermocellum strain grown on a transgenic switchgrass.« less

Bioconversion of Agricultural Waste to Ethanol by SSF Using Recombinant Cellulase from Clostridium thermocellum

PubMed Central

Mutreja, Ruchi; Das, Debasish; Goyal, Dinesh; Goyal, Arun

2011-01-01

The effect of different pretreatment methods, temperature, and enzyme concentration on ethanol production from 8 lignocellulosic agrowaste by simultaneous saccharification and fermentation (SSF) using recombinant cellulase and Saccharomyces cerevisiae were studied. Recombinant cellulase was isolated from E. coli BL21 cells transformed with CtLic26A-Cel5-CBM11 full-length gene from Clostridium thermocellum and produced in both batch and fed-batch processes. The maximum cell OD and specific activity in batch mode were 1.6 and 1.91 U/mg, respectively, whereas in the fed-batch mode, maximum cell OD and specific activity were 3.8 and 3.5 U/mg, respectively, displaying a 2-fold increase. Eight substrates, Syzygium cumini (jamun), Azadirachta indica (neem), Saracens indica (asoka), bambusa dendrocalmus (bamboo), Populas nigra (poplar), Achnatherum hymenoides (wild grass), Eucalyptus marginata (eucalyptus), and Mangifera indica (mango), were subjected to SSF. Of three pretreatments, acid, alkali, and steam explosion, acid pretreatment Syzygium cumini (Jamun) at 30°C gave maximum ethanol yield of 1.42 g/L. PMID:21811671

Bioconversion of Agricultural Waste to Ethanol by SSF Using Recombinant Cellulase from Clostridium thermocellum.

PubMed

Mutreja, Ruchi; Das, Debasish; Goyal, Dinesh; Goyal, Arun

2011-01-01

The effect of different pretreatment methods, temperature, and enzyme concentration on ethanol production from 8 lignocellulosic agrowaste by simultaneous saccharification and fermentation (SSF) using recombinant cellulase and Saccharomyces cerevisiae were studied. Recombinant cellulase was isolated from E. coli BL21 cells transformed with CtLic26A-Cel5-CBM11 full-length gene from Clostridium thermocellum and produced in both batch and fed-batch processes. The maximum cell OD and specific activity in batch mode were 1.6 and 1.91 U/mg, respectively, whereas in the fed-batch mode, maximum cell OD and specific activity were 3.8 and 3.5 U/mg, respectively, displaying a 2-fold increase. Eight substrates, Syzygium cumini (jamun), Azadirachta indica (neem), Saracens indica (asoka), bambusa dendrocalmus (bamboo), Populas nigra (poplar), Achnatherum hymenoides (wild grass), Eucalyptus marginata (eucalyptus), and Mangifera indica (mango), were subjected to SSF. Of three pretreatments, acid, alkali, and steam explosion, acid pretreatment Syzygium cumini (Jamun) at 30°C gave maximum ethanol yield of 1.42 g/L.

Bioconversion of Sugarcane Vinasse into High-Added Value Products and Energy

PubMed Central

Machado, Antonio Carlos de Oliveira

2017-01-01

Vinasse, a residue from bioethanol production containing high organic matter concentration, was used as substrate in submerged fermentation of Pseudomonas aeruginosa PA1 for biosurfactant production. About 2.7 g/L of rhamnolipids was obtained, with surface tension of 29.2 mN/m and critical micelle concentration of 80.3 mg/L. After separation of rhamnolipid and biomass, residual fermentation media were submitted to anaerobic biodegradation in mesophilic conditions. The residual medium derived from fermentation with vinasse diluted to 1 : 1, without addition of nitrogen, C : N 21, and for 168 h, led to 63.2% chemical oxygen demand (COD) removal and 97.6 mL CH4/g CODremoved. Compared to results obtained with fresh vinasse (73.7% COD removal and 112.4 mL CH4/g CODremoved), it could be concluded that both processes can be integrated in order to add value to the residue and obtain energy, reducing production costs and at the same time environmental impacts related to vinasse disposal. PMID:29250551

Isolation of autochthonous non-white rot fungi with potential for enzymatic upgrading of Venezuelan extra-heavy crude oil

PubMed Central

Naranjo, Leopoldo; Urbina, Hector; De Sisto, Angela; Leon, Vladimir

2007-01-01

The increasing world demand for fuels makes it necessary to exploit the largest reserve of extra-heavy crude oil (EHCO) of the Orinoco Oil Belt from Venezuela. We propose the use of extracellular oxidative enzymes, in particular, lignin-degrading enzyme systems (LDS) of fungi, for enzymatic improvement of EHCO. Autochthonous non-white rot fungal strains able to use EHCO, and several polycyclic aromatic hydrocarbons (PAHs) as sole carbon source and energy, were isolated from EHCO-polluted soils and identified as belonging to the genera Fusarium, Penicillium , Trichoderma , Aspergillus , Neosartorya, Pseudallescheria, Cladosporium, Pestalotiopsis , Phoma and Paecillomyces. Phenotypic and biochemical assays revealed the ability of these filamentous fungi to synthesize extracellular oxidative enzymes, and suggested a relationship between the LDS and EHCO bioconversion. This work reports, for the first time, the use of o-phenylenediamine dihydrochloride (OPD) as substrate to measure extracellular ligninolytic peroxidases (ELP) in culture broths of filamentous fungi (Fusarium solani HP-1), and constitutes the first formal study of the fungal community associated with the EHCO of the Orinoco Oil Belt. PMID:18833334

Production of Δ9-tetrahydrocannabinolic acid from cannabigerolic acid by whole cells of Pichia (Komagataella) pastoris expressing Δ9-tetrahydrocannabinolic acid synthase from Cannabis sativa L.

PubMed

Zirpel, Bastian; Stehle, Felix; Kayser, Oliver

2015-09-01

The Δ9-tetrahydrocannabinolic acid synthase (THCAS) from Cannabis sativa was expressed intracellularly in different organisms to investigate the potential of a biotechnological production of Δ9-tetrahydrocannabinolic acid (THCA) using whole cells. Functional expression of THCAS was obtained in Saccharomyces cerevisiae and Pichia (Komagataella) pastoris using a signal peptide from the vacuolar protease, proteinase A. No functional expression was achieved in Escherichia coli. The highest volumetric activities obtained were 98 pkat ml(-1) (intracellular) and 44 pkat ml(-1) (extracellular) after 192 h of cultivation at 15 °C using P. pastoris cells. Low solubility of CBGA prevents the THCAS application in aqueous cell-free systems, thus whole cells were used for a bioconversion of cannabigerolic acid (CBGA) to THCA. Finally, 1 mM (0.36 g THCA l(-1)) THCA could be produced by 10.5 gCDW l(-1) before enzyme activity was lost. Whole cells of P. pastoris offer the capability of synthesizing pharmaceutical THCA production.

The cellulose binding region in Trichoderma reesei cellobiohydrolase I has a higher capacity in improving crystalline cellulose degradation than that of Penicillium oxalicum.

PubMed

Du, Jian; Zhang, Xiu; Li, Xuezhi; Zhao, Jian; Liu, Guodong; Gao, Baoyu; Qu, Yinbo

2018-06-19

Commercial cellulase preparations for lignocellulose bioconversion are mainly produced by the fungus Trichoderma reesei. The maximum cellulose conversion of T. reesei cellulase mixture was 15%-20% higher than that of Penicillium oxalicum in the hydrolysis of corncob residue and Avicel. Nevertheless, both preparations hydrolyzed more than 92% of cellulose in NaOH-mercerized Avicel. When added to Avicel hydrolysis residue that was less reactive to P. oxalicum cellulases, cellobiohydrolase I (CBH I) from T. reesei resulted in a higher cellulose conversion than its homologous proteins from P. oxalicum and Aspergillus niger at the same protein loadings. Further domain exchange experiment attributed the high hydrolytic efficiency of T. reesei CBH I to its inter-domain linker and cellulose-binding domain. The results in part explained the superior performance of T. reesei cellulases on the degradation of native crystalline cellulose, and highlighted the important role of cellulose-binding region in determining the degree of hydrolysis by cellulases. Copyright © 2018 Elsevier Ltd. All rights reserved.

Eco-friendly methodology for efficient synthesis and scale-up of 2-ethylhexyl-p-methoxycinnamate using Rhizopus oryzae lipase and its biological evaluation.

PubMed

Kumar, Vinod; Jahan, Firdaus; Kameswaran, Karthikeya; Mahajan, Richi V; Saxena, Rajendra Kumar

2014-06-01

Lipase-mediated synthesis of phenolic acid esters is a green and economical alternative to current chemical methods. Octyl methoxycinnamate, an important UVB-absorbing compound, was synthesized by the esterification of p-methoxycinnamic acid with 2-ethyl hexanol using Rhizopus oryzae lipase. A molar ratio of 1:2 of p-methoxycinnamic acid and 2-ethyl hexanol was found to give an optimum yield using cyclo-octane (50 ml) as reaction solvent, at a temperature of 45 °C, and 750 U of lipase, resulting in a yield of 91.3 % in 96 h. This reaction was successfully scaled up to 400-ml reaction size where 88.6 %bioconversion was achieved. The synthesized compound was found to have superior antioxidant activity as compared to ascorbic acid. The synthesized compound also exhibited good antimicrobial activity against Escherichia coli, Klebsiella pneumonia, Salmonella typhi, Staphylococcus aures, Candida albicans (yeast), Aspergillus niger, Alternaria solani, and Fussarium oxysporum by well diffusion method in terms of zone of inhibitions (in mm).

Molecular Breeding Algae For Improved Traits For The Conversion Of Waste To Fuels And Commodities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bagwell, C.

This Exploratory LDRD aimed to develop molecular breeding methodology for biofuel algal strain improvement for applications in waste to energy / commodity conversion technologies. Genome shuffling technologies, specifically protoplast fusion, are readily available for the rapid production of genetic hybrids for trait improvement and have been used successfully in bacteria, yeast, plants and animals. However, genome fusion has not been developed for exploiting the remarkable untapped potential of eukaryotic microalgae for large scale integrated bio-conversion and upgrading of waste components to valued commodities, fuel and energy. The proposed molecular breeding technology is effectively sexual reproduction in algae; though compared tomore » traditional breeding, the molecular route is rapid, high-throughput and permits selection / improvement of complex traits which cannot be accomplished by traditional genetics. Genome fusion technologies are the cutting edge of applied biotechnology. The goals of this Exploratory LDRD were to 1) establish reliable methodology for protoplast production among diverse microalgal strains, and 2) demonstrate genome fusion for hybrid strain production using a single gene encoded trait as a proof of the concept.« less

Microbial Biotransformation to Obtain New Antifungals

PubMed Central

Bianchini, Luiz F.; Arruda, Maria F. C.; Vieira, Sergio R.; Campelo, Patrícia M. S.; Grégio, Ana M. T.; Rosa, Edvaldo A. R.

2015-01-01

Antifungal drugs belong to few chemical groups and such low diversity limits the therapeutic choices. The urgent need of innovative options has pushed researchers to search new bioactive molecules. Literature regarding the last 15 years reveals that different research groups have used different approaches to achieve such goal. However, the discovery of molecules with different mechanisms of action still demands considerable time and efforts. This review was conceived to present how Pharmaceutical Biotechnology might contribute to the discovery of molecules with antifungal properties by microbial biotransformation procedures. Authors present some aspects of (1) microbial biotransformation of herbal medicines and food; (2) possibility of major and minor molecular amendments in existing molecules by biocatalysis; (3) methodological improvements in processes involving whole cells and immobilized enzymes; (4) potential of endophytic fungi to produce antimicrobials by bioconversions; and (5) in silico research driving to the improvement of molecules. All these issues belong to a new conception of transformation procedures, so-called “green chemistry,” which aims the highest possible efficiency with reduced production of waste and the smallest environmental impact. PMID:26733974

Localized entrapment of green fluorescent protein within nanostructured polymer films

NASA Astrophysics Data System (ADS)

Ankner, John; Kozlovskaya, Veronika; O'Neill, Hugh; Zhang, Qiu; Kharlampieva, Eugenia

2012-02-01

Protein entrapment within ultrathin polymer films is of interest for applications in biosensing, drug delivery, and bioconversion, but controlling protein distribution within the films is difficult. We report on nanostructured protein/polyelectrolyte (PE) materials obtained through incorporation of green fluorescent protein (GFP) within poly(styrene sulfonate)/poly(allylamine hydrochloride) multilayer films assembled via the spin-assisted layer-by-layer method. By using deuterated GFP as a marker for neutron scattering contrast we have inferred the architecture of the films in both normal and lateral directions. We find that films assembled with a single GFP layer exhibit a strong localization of the GFP without intermixing into the PE matrix. The GFP volume fraction approaches the monolayer density of close-packed randomly oriented GFP molecules. However, intermixing of the GFP with the PE matrix occurs in multiple-GFP layer films. Our results yield new insight into the organization of immobilized proteins within polyelectrolyte matrices and open opportunities for fabrication of protein-containing films with well-organized structure and controllable function, a crucial requirement for advanced sensing applications.

Bioconversion of waste office paper to hydrogen using pretreated rumen fluid inoculum.

PubMed

Botta, Lívia Silva; Ratti, Regiane Priscila; Sakamoto, Isabel Kimiko; Ramos, Lucas Rodrigues; Silva, Edson Luiz; Varesche, Maria Bernadete Amâncio

2016-12-01

In this study, a microbial consortium from an acid-treated rumen fluid was used to improve the yields of H 2 production from paper residues in batch reactors. The anaerobic batch reactors, which contained paper and cellulose, were operated under three conditions: (1) 0.5 g paper/L, (2) 2 g paper/L, and (3) 4 g paper/L. Cellulase was added to promote the hydrolysis of paper to soluble sugars. The H 2 yields were 5.51, 4.65, and 3.96 mmol H 2 /g COD, respectively, with substrate degradation ranging from 56 to 65.4 %. Butyric acid was the primary soluble metabolite in the three reactors, but pronounced solventogenesis was detected in the reactors incubated with increased paper concentrations (2.0 and 4.0 g/L). A substantial prevalence of Clostridium acetobutylicum (99 % similarity) was observed in the acid-treated rumen fluid, which has been recognized as an efficient H 2 -producing strain in addition to ethanol and n-butanol which were also detected in the reactors.

Bioconversion of garden waste, kitchen waste and cow dung into value-added products using earthworm Eisenia fetida

PubMed Central

Wani, K.A.; Mamta; Rao, R.J.

2013-01-01

Solid waste management is a worldwide problem and it is becoming more and more complicated day by day due to rise in population, industrialization and changes in our life style. Transformation of industrial sludges into vermicompost is of double interest: on the one hand, a waste is converted into value added product, and, on the other, it controls a pollutant that is a consequence of increasing industrialization. Garden waste, kitchen waste and cow dung were subjected to recycle through vermicomposting by using the epigeic earthworm Eisenia fetida under field conditions. The pH, moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium in vermicompost was analysed. It was found that moisture content, total organic carbon, humus, nitrogen, phosphorous and potassium was high in cow dung, followed by kitchen waste and garden waste. This study clearly indicates that vermicomposting of garden waste, kitchen waste and cow dung can not only produce a value added produce (vermicomposting) but at the same time reduce the quantity of waste. PMID:23961230

A Bacillus megaterium System for the Production of Recombinant Proteins and Protein Complexes.

PubMed

Biedendieck, Rebekka

2016-01-01

For many years the Gram-positive bacterium Bacillus megaterium has been used for the production and secretion of recombinant proteins. For this purpose it was systematically optimized. Plasmids with different inducible promoter systems, with different compatible origins, with small tags for protein purification and with various specific signals for protein secretion were combined with genetically improved host strains. Finally, the development of appropriate cultivation conditions for the production strains established this organism as a bacterial cell factory even for large proteins. Along with the overproduction of individual proteins the organism is now also used for the simultaneous coproduction of up to 14 recombinant proteins, multiple subsequently interacting or forming protein complexes. Some of these recombinant strains are successfully used for bioconversion or the biosynthesis of valuable components including vitamins. The titers in the g per liter scale for the intra- and extracellular recombinant protein production prove the high potential of B. megaterium for industrial applications. It is currently further enhanced for the production of recombinant proteins and multi-subunit protein complexes using directed genetic engineering approaches based on transcriptome, proteome, metabolome and fluxome data.

Bioconversion of lignocellulosic residues by Agrocybe cylindracea and Pleurotus ostreatus mushroom fungi--assessment of their effect on the final product and spent substrate properties.

PubMed

Koutrotsios, Georgios; Mountzouris, Konstantinos C; Chatzipavlidis, Iordanis; Zervakis, Georgios I

2014-10-15

Nine agro-industrial and forestry by-products were subjected to solid-state fermentation by Agrocybe cylindracea and Pleurotus ostreatus, and the process and end-products were comparatively evaluated. Grape marc waste plus cotton gin trash was the best performing medium for both fungi, while substrate composition had a marked effect on most cultivation parameters. Biological efficiency was positively correlated with nitrogen, lignin and ash, and negatively with hemicelluloses and carbohydrate content of substrates. Spent substrates demonstrated high reductions in hemicelluloses and cellulose in contrast to lignin; fibre fractions were correlated with nitrogen, fat and ash content of initial materials, while residual mycelial biomass was affected by mushroom productivity. Mushroom proximate analysis revealed significant variations of constituents depending on the substrate. Crude protein and fat were correlated with substrates nitrogen for both species. Alternative cultivation substrates of high potential are proposed, while spent material could be exploited as animal feed due to its upgraded properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

Arsenic in the human food chain, biotransformation and toxicology--Review focusing on seafood arsenic.

PubMed

Molin, Marianne; Ulven, Stine Marie; Meltzer, Helle Margrete; Alexander, Jan

2015-01-01

Fish and seafood are main contributors of arsenic (As) in the diet. The dominating arsenical is the organoarsenical arsenobetaine (AB), found particularly in finfish. Algae, blue mussels and other filter feeders contain less AB, but more arsenosugars and relatively more inorganic arsenic (iAs), whereas fatty fish contain more arsenolipids. Other compounds present in smaller amounts in seafood include trimethylarsine oxide (TMAO), trimethylarsoniopropionate (TMAP), dimethylarsenate (DMA), methylarsenate (MA) and sulfur-containing arsenicals. The toxic and carcinogenic arsenical iAs is biotransformed in humans and excreted in urine as the carcinogens dimethylarsinate (DMA) and methylarsonate (MA), producing reactive intermediates in the process. Less is known about the biotransformation of organoarsenicals, but new insight indicates that bioconversion of arsenosugars and arsenolipids in seafood results in urinary excretion of DMA, possibly also producing reactive trivalent arsenic intermediates. Recent findings also indicate that the pre-systematic metabolism by colon microbiota play an important role for human metabolism of arsenicals. Processing of seafood may also result in transformation of arsenicals. Copyright © 2015 Elsevier GmbH. All rights reserved.

Metabolic engineering of E. coli top 10 for production of vanillin through FA catabolic pathway and bioprocess optimization using RSM.

PubMed

Chakraborty, Debkumar; Gupta, Gaganjot; Kaur, Baljinder

2016-12-01

Metabolic engineering and construction of recombinant Escherichia coli strains carrying feruloyl-CoA synthetase and enoyl-CoA hydratase genes for the bioconversion of ferulic acid to vanillin offers an alternative way to produce vanillin. Isolation and designing of fcs and ech genes was carried out using computer assisted protocol and the designed vanillin biosynthetic gene cassette was cloned in pCCIBAC expression vector for introduction in E. coli top 10. Recombinant strain was implemented for the statistical optimization of process parameters influencing F A to vanillin biotransformation. CCD matrix constituted of process variables like FA concentration, time, temperature and biomass with intracellular, extracellular and total vanillin productions as responses. Production was scaled up and 68 mg/L of vanillin was recovered from 10 mg/L of FA using cell extracts from 1 mg biomass within 30 min. Kinetic activity of enzymes were characterized. From LCMS-ESI analysis a metabolic pathway of FA degradation and vanillin production was predicted. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of β-Cyclodextrin Complexation on Solubility and Enzymatic Conversion of Naringin

PubMed Central

Cui, Li; Zhang, Zhen-Hai; Sun, E; Jia, Xiao-Bin

2012-01-01

In the present paper, the effect of β-cyclodextrin (β-CD) inclusion complexation on the solubility and enzymatic hydrolysis of naringin was investigated. The inclusion complex of naringin/β-CD at the molar ratio of 1:1 was obtained by the dropping method and was characterized by differential scanning calorimetry. The solubility of naringin complexes in water at 37 ± 0.1 °C was 15 times greater than that of free naringin. Snailase-involved hydrolysis conditions were tested for the bioconversion of naringin into naringenin using the univariate experimental design. Naringin can be transformed into naringenin by snailase-involved hydrolysis. The optimum conditions for enzymatic hydrolysis were determined as follows: pH 5.0, temperature 37 °C, ratio of snailase/substrate 0.8, substrate concentration 20 mg·mL−1, and reaction time 12 h. Under the optimum conditions, the transforming rate of naringenin from naringin for inclusion complexes and free naringin was 98.7% and 56.2% respectively, suggesting that β-CD complexation can improve the aqueous solubility and consequently the enzymatic hydrolysis rate of naringin. PMID:23203062

Using wastewater after lipid fermentation as substrate for bacterial cellulose production by Gluconacetobacter xylinus.

PubMed

Huang, Chao; Guo, Hai-Jun; Xiong, Lian; Wang, Bo; Shi, Si-Lan; Chen, Xue-Fang; Lin, Xiao-Qing; Wang, Can; Luo, Jun; Chen, Xin-De

2016-01-20

In this study, lipid fermentation wastewater (fermentation broth after separation with yeast biomass) with high Chemical Oxygen Demand (COD) value of 25,591 mg/L was used as substrate for bacterial cellulose (BC) production by Gluconacetobacter xylinus for the first time. After 5 days of fermentation, the highest BC yield (0.659 g/L) was obtained. Both monosaccharide and polysaccharides present in lipid fermentation wastewater could be utilized by G. xylinus simultaneously during fermentation. By this bioconversion, 30.0% of COD could be removed after 10 days of fermentation and the remaining wastewater could be used for further BC fermentation. The crystallinity of BC samples in lipid fermentation wastewater increased gradually during fermentation but overall the environment of lipid fermentation wastewater showed small influence on BC structure by comparison with that in traditional HS medium by using FE-SEM, FTIR, and XRD. By this work, the possibility of using lipid fermentation wastewater containing low value carbohydrate polymer (extracellular polysaccharides) for high value carbohydrate polymer (BC) production was proven. Copyright © 2015 Elsevier Ltd. All rights reserved.

Real-time understanding of lignocellulosic bioethanol fermentation by Raman spectroscopy

PubMed Central

2013-01-01

Background A substantial barrier to commercialization of lignocellulosic ethanol production is a lack of process specific sensors and associated control strategies that are essential for economic viability. Current sensors and analytical techniques require lengthy offline analysis or are easily fouled in situ. Raman spectroscopy has the potential to continuously monitor fermentation reactants and products, maximizing efficiency and allowing for improved process control. Results In this paper we show that glucose and ethanol in a lignocellulosic fermentation can be accurately monitored by a 785 nm Raman spectroscopy instrument and novel immersion probe, even in the presence of an elevated background thought to be caused by lignin-derived compounds. Chemometric techniques were used to reduce the background before generating calibration models for glucose and ethanol concentration. The models show very good correlation between the real-time Raman spectra and the offline HPLC validation. Conclusions Our results show that the changing ethanol and glucose concentrations during lignocellulosic fermentation processes can be monitored in real-time, allowing for optimization and control of large scale bioconversion processes. PMID:23425590

Applications of the Non-Conventional Yeast Yarrowia lipolytica

NASA Astrophysics Data System (ADS)

Thevenieau, France; Nicaud, Jean-Marc; Gaillardin, Claude

The yeast Yarrowia lipolytica is often found associated to proteinaceous or hydrophobic substrates such as alkanes or lipids. To assimilate these hydropho-bic substrates, Y. lipolytica has developed an adaptative strategy resulting in elaborated morphological and physiological changes leading to terminal and β-oxidation of substrates as well as to lipid storage. The completion of the Y. lipolytica genome greatly improved our understanding of these mechanisms. Three main applications of this metabolism will be discussed. The first class corresponds to bioconver-sion processes for the production of secondary metabolites (citric acid), of aroma ( γ - lactone, green note, epoxy geraniol) and of chemicals (dicarboxylic acids). The second class leads to fine chemical production by enantio separation of pharmaceutical compounds using Y. lipolytica enzymes such as epoxyde hydrolase or lipase. The third one refers to production of Single Cell Oils (SCO) from agriculture feedstock. In addition to its ability to handle hydrophobic substrates, Y. lipolytica has also been recognised as a strong secretor of various proteins such as proteases, lipases, RNases and others. A comprehensive review of recent developments of the Y. lipolytica expression/secretion system will finally be presented.

Enrichment of microbial communities tolerant to the ionic liquids tetrabutylphosphonium chloride and tributylethylphosphonium diethylphosphate

DOE PAGES

Pace, Sara; Ceballos, Shannon J.; Harrold, Duff; ...

2016-04-22

Our aims were to identify thermophilic microbial communities that degrade green waste in the presence of the ionic liquids (IL) tetrabutylphosphonium chloride and tributylethylphosphonium diethylphosphate and examine preservation methods for IL-tolerant communities. High-solids incubations with stepwise increases in IL concentration were conducted to enrich for thermophilic IL-tolerant communities that decomposed green waste. 16S rRNA sequencing of enriched communities revealed microorganisms capable of tolerating high levels of IL. Furthermore, cryogenic preservation of enriched communities reduced the IL tolerance of the community and decreased the relative abundance of IL-tolerant organisms. The use of cryoprotectants did not have an effect on microbial activitymore » on green waste of the stored community. A successful approach was developed to enrich communities that decompose green waste in thermophilic high-solids environments in the presence of IL. Alternative community storage and revival methods are necessary for maintenance and recovery of IL-tolerant communities. The enriched communities provide a targeted source of enzymes for the bioconversion of IL-pretreated green waste for conversion to biofuels.« less

Production of D-tagatose and bioethanol from onion waste by an intergrating bioprocess.

PubMed

Kim, Ho Myeong; Song, Younho; Wi, Seung Gon; Bae, Hyeun-Jong

2017-10-20

The rapid increase of agricultural waste is becoming a burgeoning problem and considerable efforts are being made by numerous researchers to convert it into a high-value resource material. Onion waste is one of the biggest issues in a world of dwindling resource. In this study, the potential of onion juice residue (OJR) for producing valuable rare sugar or bioethanol was evaluated. Purified Paenibacillus polymyxaL-arabinose isomerase (PPAI) has a molecular weight of approximately 53kDa, and exhibits maximal activity at 30°C and pH 7.5 in the presence of 0.8mM Mn 2+ . PPAI can produce 0.99g D-tagatose from 10g OJR. In order to present another application for OJR, we produced 1.56g bioethanol from 10g OJR through a bioconversion and fermentation process. These results indicate that PPAI can be used for producing rare sugars in an industrial setting, and OJR can be converted to D-tagatose and bioethanol. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411

PubMed Central

Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

2015-01-01

Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47–0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2–2.7 g/L/h and a total sugar conversion of 90–99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

Bioconversion of agro-industrial by-products in rhamnolipids toward applications in enhanced oil recovery and bioremediation.

PubMed

Gudiña, Eduardo J; Rodrigues, Ana I; Alves, Eliana; Domingues, M Rosário; Teixeira, José A; Rodrigues, Lígia R

2015-02-01

In this work, biosurfactant production by a Pseudomonas aeruginosa strain was optimized using low-cost substrates. The highest biosurfactant production (3.2 g/l) was obtained using a culture medium containing corn steep liquor (10% (v/v)) and molasses (10% (w/v)). The biosurfactant reduced the surface tension of water up to 30 mN/m, and exhibited a high emulsifying activity (E24=60%), with a critical micelle concentration as low as 50 mg/l. The biosurfactant produced in this alternative medium was characterized as a mixture of eight different rhamnolipid congeners, being the most abundant the mono-rhamnolipid Rha-C10-C10. However, using LB medium, nine different rhamnolipid congeners were identified, being the most abundant the di-rhamnolipid Rha-Rha-C10-C10. The rhamnolipid mixture produced in the alternative medium exhibited a better performance in removing oil from contaminated sand when compared with two chemical surfactants, suggesting its potential use as an alternative to traditional chemical surfactants in enhanced oil recovery or bioremediation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity.

PubMed

Gupta, Sonika; Sharma, Parul; Dev, Kamal; Sourirajan, Anuradha

2016-01-01

The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products.

Halophilic Bacteria of Lunsu Produce an Array of Industrially Important Enzymes with Salt Tolerant Activity

PubMed Central

Gupta, Sonika; Sharma, Parul; Dev, Kamal; Sourirajan, Anuradha

2016-01-01

The halophilic bacterial isolates SS1, SS2, SS3, SS5, and SS8 were characterized for production of industrially important enzymes like amylase, protease, lipase, and glutaminase. Halophilic bacterial isolates SS1 and SS3 exhibited salt dependent extracellular amylase and protease activities. Both the halophilic isolates SS1 and SS3 exhibited maximum amylase and protease activities in the presence of 1.5 and 1.0 M NaCl, respectively, with the optimum pH 8 and temperature 40°C. SS2 showed maximum extracellular protease and lipase activities in the presence of 0.75 M NaCl, at optimum pH of 7, and temperature 37°C. The glutaminase activity of SS3 increased with increase in concentration of NaCl up to 2.5 M. The optimum pH and temperature for L-glutaminase activity of SS3 was 8 and 40°C, respectively. The combined hydrolytic activities of these halophilic bacterial isolates can be used for bioconversion of organic materials to useful products. PMID:26885394

Production of Glucaric Acid from Hemicellulose Substrate by Rosettasome Enzyme Assemblies.

PubMed

Lee, Charles C; Kibblewhite, Rena E; Paavola, Chad D; Orts, William J; Wagschal, Kurt

2016-07-01

Hemicellulose biomass is a complex polymer with many different chemical constituents that can be utilized as industrial feedstocks. These molecules can be released from the polymer and transformed into value-added chemicals through multistep enzymatic pathways. Some bacteria produce cellulosomes which are assemblies composed of lignocellulolytic enzymes tethered to a large protein scaffold. Rosettasomes are artificial engineered ring scaffolds designed to mimic the bacterial cellulosome. Both cellulosomes and rosettasomes have been shown to facilitate much higher rates of biomass hydrolysis compared to the same enzymes free in solution. We investigated whether tethering enzymes involved in both biomass hydrolysis and oxidative transformation to glucaric acid onto a rosettasome scaffold would result in an analogous production enhancement in a combined hydrolysis and bioconversion metabolic pathway. Three different enzymes were used to hydrolyze birchwood hemicellulose and convert the substituents to glucaric acid, a top-12 DOE value added chemical feedstock derived from biomass. It was demonstrated that colocalizing the three different enzymes to the synthetic scaffold resulted in up to 40 % higher levels of product compared to uncomplexed enzymes.

Conversion of corn stover alkaline pre-treatment waste streams into biodiesel via Rhodococci

DOE PAGES

Le, Rosemary K.; Wells Jr., Tyrone; Das, Parthapratim; ...

2017-01-13

We present the bioconversion of second-generation cellulosic ethanol waste streams into biodiesel via oleaginous bacteria is a novel optimization strategy for biorefineries with substantial potential for rapid development. In this study, one- and two-stage alkali/alkali-peroxide pretreatment waste streams of corn stover were separately implemented as feedstocks in 96 h batch reactor fermentations with wild-type Rhodococcus opacus PD 630, R. opacus DSM 1069, and R. jostii DSM 44719 T . Here we show using 31P-NMR, HPAECPAD, and SEC analyses, that the more rigorous and chemically-efficient two-stage chemical pretreatment effluent provided higher concentrations of solubilized glucose and lower molecular weight (70 300more » g mol1 ) lignin degradation products thereby enabling improved cellular density, viability, and oleaginicity in each respective strain. The most significant yields were by R. opacus PD 630, which converted 6.2% of organic content with a maximal total lipid production of 1.3 g L1 and accumulated 42.1% in oils based on cell dry weight after 48 h.« less

Environmentally safe production of 7-aminodeacetoxycephalosporanic acid (7-ADCA) using recombinant strains of Acremonium chrysogenum.

PubMed

Velasco, J; Luis Adrio, J; Angel Moreno, M; Díez, B; Soler, G; Barredo, J L

2000-08-01

Medically useful semisynthetic cephalosporins are made from 7-aminodeacetoxycephalosporanic acid (7-ADCA) or 7-aminocephalosporanic acid (7-ACA). Here we describe a new industrially amenable bioprocess for the production of the important intermediate 7-ADCA that can replace the expensive and environmentally unfriendly chemical method classically used. The method is based on the disruption and one-step replacement of the cefEF gene, encoding the bifunctional expandase/hydroxylase activity, of an actual industrial cephalosporin C production strain of Acremonium chrysogenum. Subsequent cloning and expression of the cefE gene from Streptomyces clavuligerus in A. chrysogenum yield recombinant strains producing high titers of deacetoxycephalosporin C (DAOC). Production level of DAOC is nearly equivalent (75-80%) to the total beta-lactams biosynthesized by the parental overproducing strain. DAOC deacylation is carried out by two final enzymatic bioconversions catalyzed by D-amino acid oxidase (DAO) and glutaryl acylase (GLA) yielding 7-ADCA. In contrast to the data reported for recombinant strains of Penicillium chrysogenum expressing ring expansion activity, no detectable contamination with other cephalosporin intermediates occurred.

Thermodynamic analysis of the energy recovery from the aerobic bioconversion of solid urban waste organic fraction.

PubMed

Di Maria, Francesco; Benavoli, Manuel; Zoppitelli, Mirco

2008-01-01

Waste management is of the utmost importance for many countries and especially for highly developed ones due to its implications on society. In particular, proper treatment before disposal of the solid urban waste organic fraction is one of the main issues that is addressed in waste management. In fact, the organic fraction is particularly reactive and if disposed in sanitary landfills without previous adequate treatment, a large amount of dangerous and polluting gaseous, liquid and solid substances can be produced. Some waste treatment processes can also present an opportunity to produce other by-products like energy, recycled materials and other products with both economic and environmental benefits. In this paper, the aerobic treatment of the organic fraction of solid urban waste, performed in a biocell plant with the possibility of recovering heat for civil or industrial needs, was examined from the thermodynamic point of view. A theoretical model was proposed both for the biological process of the organic fraction, as well as for the heat recovery system. The most significant results are represented and discussed.

Direct utilization of waste water algal biomass for ethanol production by cellulolytic Clostridium phytofermentans DSM1183.

PubMed

Fathima, Anwar Aliya; Sanitha, Mary; Kumar, Thangarathinam; Iyappan, Sellamuthu; Ramya, Mohandass

2016-02-01

Direct bioconversion of waste water algal biomass into ethanol using Clostridium phytofermentans DSM1183 was demonstrated in this study. Fermentation of 2% (w/v) autoclaved algal biomass produced ethanol concentration of 0.52 g L(-1) (solvent yield of 0.19 g/g) where as fermentation of acid pretreated algal biomass (2%, w/v) produced ethanol concentration of 4.6 g L(-1) in GS2 media (solvent yield of 0.26 g/g). The control experiment with 2% (w/v) glucose in GS2 media produced ethanol concentration of 2.8 g L(-1) (solvent yield of 0.25 g/g). The microalgal strains from waste water algal biomass were identified as Chlamydomonas dorsoventralis, Graesiella emersonii, Coelastrum proboscideum, Scenedesmus obliquus, Micractinium sp., Desmodesmus sp., and Chlorella sp., based on ITS-2 molecular marker. The presence of glucose, galactose, xylose and rhamnose were detected by high performance liquid chromatography in the algal biomass. Scanning Electron Microscopy observations of fermentation samples showed characteristic morphological changes in algal cells and bioaccessibility of C. phytofermentans. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design and installation of a next generation pilot scale fermentation system.

PubMed

Junker, B; Brix, T; Lester, M; Kardos, P; Adamca, J; Lynch, J; Schmitt, J; Salmon, P

2003-01-01

Four new fermenters were designed and constructed for use in secondary metabolite cultivations, bioconversions, and enzyme production. A new PC/PLC-based control system also was implemented using GE Fanuc PLCs, Genius I/O blocks, and Fix Dynamics SCADA software. These systems were incorporated into an industrial research fermentation pilot plant, designed and constructed in the early 1980s. Details of the design of these new fermenters and the new control system are described and compared with the existing installation for expected effectiveness. In addition, the reasoning behind selection of some of these features has been included. Key to the design was the goal of preserving similarity between the new and previously existing and successfully utilized fermenter hardware and software installations where feasible but implementing improvements where warranted and beneficial. Examples of enhancements include strategic use of Inconel as a material of construction to reduce corrosion, piping layout design for simplified hazardous energy isolation, on-line calculation and control of nutrient feed rates, and the use of field I/O modules located near the vessel to permit low-cost addition of new instrumentation.

Physico-Chemical Alternatives in Lignocellulosic Materials in Relation to the Kind of Component for Fermenting Purposes

PubMed Central

Coz, Alberto; Llano, Tamara; Cifrián, Eva; Viguri, Javier; Maican, Edmond; Sixta, Herbert

2016-01-01

The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and -bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO2, due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given. PMID:28773700

Evaluation of diclofenac prodrugs for enhancing transdermal delivery.

PubMed

Lobo, Shabbir; Li, Henan; Farhan, Nashid; Yan, Guang

2014-03-01

Abstract Objective: The purpose of this study was to evaluate the approach of using diclofenac acid (DA) prodrugs for enhancing transdermal delivery. Methanol diclofenac ester (MD), ethylene glycol diclofenac ester (ED), glycerol diclofenac ester (GD) and 1,3-propylene glycol diclofenac ester (PD) were synthesized and evaluated for their physicochemical properties such as solubilities, octanol/water partition coefficients, stratum corneum/water partition coefficients, hydrolysis rates and bioconversion rates. In vitro fluxes across human epidermal membrane (HEM) in the Franz diffusion cell were determined on DA-, MD-, ED-, GD- and PD-saturated aqueous solutions. The formation of GD and ED led to the prodrugs with higher aqueous solubilities and lower partition coefficients than those of the parent drug. Prodrugs with improved aqueous solubility showed better fluxes across HEM in aqueous solution than that of the parent drug, with GD showing the highest aqueous solubility and also the highest flux. There is a linear relationship between the aqueous solubility and flux for DA, ED and PD, but GD and MD deviated from the linear line. Diclofenac prodrugs with improved hydrophilicity than the parent drug could be utilized for enhancing transdermal diclofenac delivery.

Carbon monoxide fermentation to ethanol by Clostridium autoethanogenum in a bioreactor with no accumulation of acetic acid.

PubMed

Abubackar, Haris Nalakath; Veiga, María C; Kennes, Christian

2015-06-01

Fermentation of CO or syngas offers an attractive route to produce bioethanol. However, during the bioconversion, one of the challenges to overcome is to reduce the production of acetic acid in order to minimize recovery costs. Different experiments were done with Clostridium autoethanogenum. With the addition of 0.75 μM tungsten, ethanol production from carbon monoxide increased by about 128% compared to the control, without such addition, in batch mode. In bioreactors with continuous carbon monoxide supply, the maximum biomass concentration reached at pH 6.0 was 109% higher than the maximum achieved at pH 4.75 but, interestingly, at pH 4.75, no acetic acid was produced and the ethanol titer reached a maximum of 867 mg/L with minor amounts of 2,3-butanediol (46 mg/L). At the higher pH studied (pH 6.0) in the continuous gas-fed bioreactor, almost equal amounts of ethanol and acetic acid were formed, reaching 907.72 mg/L and 910.69 mg/L respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Selective synthesis of human milk fat-style structured triglycerides from microalgal oil in a microfluidic reactor packed with immobilized lipase.

PubMed

Wang, Jun; Liu, Xi; Wang, Xu-Dong; Dong, Tao; Zhao, Xing-Yu; Zhu, Dan; Mei, Yi-Yuan; Wu, Guo-Hua

2016-11-01

Human milk fat-style structured triacylglycerols were produced from microalgal oil in a continuous microfluidic reactor packed with immobilized lipase for the first time. A remarkably high conversion efficiency was demonstrated in the microreactor with reaction time being reduced by 8 times, Michaelis constant decreased 10 times, the lipase reuse times increased 2.25-fold compared to those in a batch reactor. In addition, the content of palmitic acid at sn-2 position (89.0%) and polyunsaturated fatty acids at sn-1, 3 positions (81.3%) are slightly improved compared to the product in a batch reactor. The increase of melting points (1.7°C) and decrease of crystallizing point (3°C) implied higher quality product was produced using the microfluidic technology. The main cost can be reduced from $212.3 to $14.6 per batch with the microreactor. Overall, the microfluidic bioconversion technology is promising for modified functional lipids production allowing for cost-effective approach to produce high-value microalgal coproducts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combined strategy of transcription factor manipulation and β-glucosidase gene overexpression in Trichoderma reesei and its application in lignocellulose bioconversion.

PubMed

Xia, Ying; Yang, Lirong; Xia, Liming

2018-06-16

The industrial application of Trichoderma reesei has been greatly limited by insufficient β-glucosidase activity in its cellulase system. In this study, a novel β-glucosidase expression cassette was constructed and integrated at the target site in T. reesei ZU-02, which achieved the overexpression of β-glucosidase gene and in situ disruption of the cellulase transcriptional repressor ACE1. The resulting transformants showed significant increase in both β-glucosidase activity (BGA) and filter paper activity (FPA). The BGA and FPA increased to 25.13 IU/mL and 20.06 FPU/mL, respectively, 167- and 2.45-fold higher than that of the host strain. Meanwhile, the obtained cellulase system exhibited improved ratio of BGA to FPA, leading to better synergistic effect between cellulase components. Furthermore, submerged fermentation of the transformant was established in 50 m 3 fermenter yielding 112.2 IU/mL β-glucosidase and 89.76 FPU/mL total cellulase. The newly constructed T. reesei transformant achieved improved hydrolysis yield (90.6%) with reduced enzyme loading (15 FPU/g substrate).

Simultaneous biogas upgrading and centrate treatment in an outdoors pilot scale high rate algal pond.

PubMed

Posadas, Esther; Marín, David; Blanco, Saúl; Lebrero, Raquel; Muñoz, Raúl

2017-05-01

The bioconversion of biogas to biomethane coupled to centrate treatment was evaluated in an outdoors pilot scale high rate algal pond interconnected to an external CO 2 -H 2 S absorption column (AC) via settled broth recirculation. CO 2 -removal efficiencies ranged from 50 to 95% depending on the alkalinity of the cultivation broth and environmental conditions, while a complete H 2 S removal was achieved regardless of the operational conditions. A maximum CH 4 concentration of 94% with a limited O 2 and N 2 stripping was recorded in the upgraded biogas at recycling liquid/biogas ratios in the AC of 1 and 2. Process operation at a constant biomass productivity of 15gm -2 d -1 and the minimization of effluent generation supported high carbon and nutrient recoveries in the harvested biomass (C=66±8%, N=54±18%, P≈100% and S=16±3%). Finally, a low diversity in the structure of the microalgae population was promoted by the environmental and operational conditions imposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of dilute sulfuric acid pretreatment to maximize combined sugar yield from sugarcane bagasse for ethanol production.

PubMed

Benjamin, Y; Cheng, H; Görgens, J F

2014-01-01

Increasing fermentable sugar yields per gram of biomass depends strongly on optimal selection of varieties and optimization of pretreatment conditions. In this study, dilute acid pretreatment of bagasse from six varieties of sugarcane was investigated in connection with enzymatic hydrolysis for maximum combined sugar yield (CSY). The CSY from the varieties were also compared with the results from industrial bagasse. The results revealed considerable differences in CSY between the varieties. Up to 22.7 % differences in CSY at the optimal conditions was observed. The combined sugar yield difference between the best performing variety and the industrial bagasse was 34.1 %. High ratio of carbohydrates to lignin and low ash content favored the release of sugar from the substrates. At mild pretreatment conditions, the differences in bioconversion efficiency between varieties were greater than at severe condition. This observation suggests that under less severe conditions the glucose recovery was largely determined by chemical composition of biomass. The results from this study support the possibility of increasing sugar yields or improving the conversion efficiency when pretreatment optimization is performed on varieties with improved properties.

Anaerobic biotransformation of roxarsone and related N-substituted phenylarsonic acids

USGS Publications Warehouse

Cortinas, I.; Field, J.A.; Kopplin, M.; Garbarino, J.R.; Gandolfi, A.J.; Sierra-Alvarez, R.

2006-01-01

Large quantities of arsenic are introduced into the environment through land application of poultry litter containing the organoarsenical feed additive roxarsone (3-nitro-4-hydroxyphenylarsonic acid). The objective of this study was to evaluate the bioconversion of roxarsone and related N-substituted phenylarsonic acid derivatives under anaerobic conditions. The results demonstrate that roxarsone is rapidly transformed in the absence of oxygen to the corresponding aromatic amine, 4-hydroxy-3-aminophenylarsonic acid (HAPA). The formation of HAPA is attributable to the facile reduction of the nitro group. Electron-donating substrates, such as hydrogen gas, glucose, and lactate, stimulated the rate of nitro group reduction, indicating a microbial role. During long-term incubations, HAPA and the closely related 4-aminophenylarsonic acid (4-APA) were slowly biologically eliminated by up to 99% under methanogenic and sulfate-reducing conditions, whereas little or no removal occurred in heat-killed inoculum controls. Arsenite and, to a lesser extent, arsenate were observed as products of the degradation. Freely soluble forms of the inorganic arsenical species accounted for 19-28% of the amino-substituted phenylarsonic acids removed. This constitutes the first report of a biologically catalyzed rupture of the phenylarsonic group under anaerobic conditions. ?? 2006 American Chemical Society.