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1.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1334-1345, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748591

RESUMO

Lycopene, as a high value-added terpene compound, has been widely concerned by researchers at home and abroad. Firstly, the ability of lycopene synthesis of Saccharomyces cerevisiae model strains S288c and YPH499 was analyzed and compared. The results showed that YPH499 was more suitable for lycopene synthesis as yeast chassis. Subsequently, the effects of constitutive promoters GPDpr, TEF1pr and inducible promoters GAL1pr, GAL10pr on Lycopene synthesis were compared. The results showed that when GPDpr and TEF1pr were used as promoters of crtE, crtB and crtI in lycopene synthesis pathway, the production of lycopene was 15.31 mg/L after 60 h fermentation in shaking flask. When GAL1pr and GAL10pr were used as promoters, the production was 123.89 mg/L, which was 8.09 times higher. In addition, the methylvaleric acid (MVA) pathway was further modified to overexpress the key enzyme gene of N-terminal truncation, tHMG1 (3-hydroxy-3-methylglutaryl coenzyme A reductase). The lycopene production was 265.68 mg/L, and the yield per cell was 72.79 mg/g. The Saccharomyces cerevisiae strain designed and constructed in this study can express lycopene in high yield per cell, thus could be used in the industrial production of lycopene after further construction and optimization.


Assuntos
Microbiologia Industrial , Saccharomyces cerevisiae , Vias Biossintéticas/genética , Fermentação , Licopeno/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Especificidade da Espécie
2.
PLoS Comput Biol ; 16(7): e1008110, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32716928

RESUMO

The concept of minimal cut sets (MCS) provides a flexible framework for analyzing properties of metabolic networks and for computing metabolic intervention strategies. In particular, it has been used to support the targeted design of microbial strains for bio-based production processes. Herein we present a number of major extensions that generalize the existing MCS approach and broaden its scope for applications in metabolic engineering. We first introduce a modified approach to integrate gene-protein-reaction associations (GPR) in the metabolic network structure for the computation of gene-based intervention strategies. In particular, we present a set of novel compression rules for GPR associations, which effectively speedup the computation of gene-based MCS by a factor of up to one order of magnitude. These rules are not specific for MCS and as well applicable to other computational strain design methods. Second, we enhance the MCS framework by allowing the definition of multiple target (undesired) and multiple protected (desired) regions. This enables precise tailoring of the metabolic solution space of the designed strain with unlimited flexibility. Together with further generalizations such as individual cost factors for each intervention, direct combinations of reaction/gene deletions and additions as well as the possibility to search for substrate co-feeding strategies, the scope of the MCS framework could be broadly extended. We demonstrate the applicability and performance benefits of the described developments by computing (gene-based) Escherichia coli strain designs for the bio-based production of 2,3-butanediol, a chemical, that has recently received much attention in the field of metabolic engineering. With our extended framework, we could identify promising strain designs that were formerly unpredictable, including those based on substrate co-feeding.


Assuntos
Escherichia coli/genética , Deleção de Genes , Engenharia Metabólica/métodos , Redes e Vias Metabólicas , Trifosfato de Adenosina/química , Aerobiose , Algoritmos , Butileno Glicóis/farmacologia , Simulação por Computador , Microbiologia Industrial , Modelos Biológicos , Modelos Estatísticos , Oxirredução , Processos Estocásticos
3.
PLoS One ; 15(7): e0236739, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730333

RESUMO

Rhodopseudomonas palustris PS3 is one of the purple phototrophic non-sulfur bacteria (PNSB), which have plant growth-promoting effects on various plants. To expand the scale of PS3 fermentation in a time- and cost-effective fashion, the purpose of this work was to evaluate the use of low-cost materials as culture media and to optimize the culture conditions via response surface methodology. Corn steep liquor (CSL) and molasses were identified as potential materials to replace the nitrogen and carbon sources, respectively, in the conventional growth medium. The optimum culture conditions identified through central composite design were CSL, 39.41 mL/L; molasses, 32.35 g/L; temperature, 37.9°C; pH, 7.0; and DO 30%. Under the optimized conditions, the biomass yield reached 2.18 ± 0.01 g/L at 24 hours, which was 7.8-fold higher than that under the original medium (0.28 ± 0.01 g/L). The correlation between the predicted and experimental values of the model was over 98%, which verified the validity of the response models. Furthermore, we verified the effectiveness of the R. palustris PS3 inoculant grown under the newly developed culture conditions for plant growth promotion. This study provides a potential strategy for improving the fermentation of R. palustris PS3 in low-cost media for large-scale industrial production.


Assuntos
Carbono/metabolismo , Meios de Cultura/química , Meios de Cultura/economia , Nitrogênio/metabolismo , Desenvolvimento Vegetal , Rodopseudomonas/crescimento & desenvolvimento , Meios de Cultura/metabolismo , Fermentação , Microbiologia Industrial , Rodopseudomonas/metabolismo
4.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1031-1040, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597054

RESUMO

The use of microbial cell factories to achieve efficient conversion of raw materials and synthesis of target substances is one of the important research directions of synthetic biology. Traditional industrial microorganisms have mainly used sugar-based raw materials as fermentation substrates. How to adopt cheaper carbon resources and realize their efficient use has been widely concerned. Formic acid is an important organic one-carbon source and widely used in industrial manufacturing of pesticides, leather, dyes, medicine and rubber. In recent years, due to the demand fluctuation in downstream industries, formic acid production is facing the dilemma of overcapacity, and therefore, requiring new conversion paths for expansion and extension of the related industrial chain. Biological route is one of the important options. However, natural formate-utilizing microorganisms generally grow slowly when metabolizing formic acid, and moreover, are difficult to be artificially modified by the absence of effective genetic tools. Construction of non-natural formate-utilizing microorganisms is another alternative strategy, but still in its infancy and has a huge space for further improvements. Here, we briefly summarize the recent research progress of biological utilization of formic acid, and also propose the future research focus and direction.


Assuntos
Formiatos , Microbiologia Industrial , Fermentação , Formiatos/metabolismo , Microbiologia Industrial/tendências , Biologia Sintética/tendências
5.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1083-1100, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597059

RESUMO

Chlorinated hydrocarbons (CAHs) threaten human health and the ecological environment due to their strong carcinogenic, teratogenic, mutagenic and heritable properties. Heterotrophic assimilation degradation can completely and effectively degrade CAHs, without secondary pollution. However, it is crucial to comprehensively understand the heterotrophic assimilation process of CAHs for its application. Therefore, we review here the characteristics and advantages of heterotrophic assimilation degradation of CAHs. Moreover, we systematically summarize current research status of heterotrophic assimilation of CAHs. Furthermore, we analyze bacterial genera and metabolism, key enzymes and characteristic genes involved in the metabolic process. Finally, we indicate existing problems of heterotrophic assimilation research and future research needs.


Assuntos
Hidrocarbonetos Clorados , Microbiologia Industrial , Bactérias/metabolismo , Biodegradação Ambiental , Hidrocarbonetos Clorados/metabolismo , Microbiologia Industrial/tendências
6.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1101-1112, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597060

RESUMO

As an important platform compound, 3-hydroxypropionic acid (3-HP) can be used as a substrate to synthesize a variety of biological products with commercial potential. The titer of 3-HP by wild-type bacteria is low, which severely limits the large-scale application and production of 3-HP. By modifying the genes related to the metabolic pathway, engineered bacteria using cheap substrates as carbon sources are constructed, the aim of reducing production cost and increasing output is realized. In this paper, the recent progress in the synthesis of 3-HP by metabolic engineering at home and abroad is reviewed. The advantages and disadvantages of glycerol pathway, malonyl-CoA pathway and beta-alanine pathway for synthesis of 3-HP are also summarized and analyzed, and the future development of 3-HP is prospected.


Assuntos
Microbiologia Industrial , Ácido Láctico/análogos & derivados , Engenharia Metabólica , Glicerol/metabolismo , Microbiologia Industrial/tendências , Ácido Láctico/biossíntese , Redes e Vias Metabólicas/genética
7.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1126-1137, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597062

RESUMO

Bacitracin is a broad-spectrum cyclic peptide antibiotic, and mainly produced by Bacillus. Energy metabolism plays as a critical role in high-level production of target metabolites. In this study, Bacillus licheniformis DW2, an industrial strain for bacitracin production, was served as the original strain. First, our results confirmed that elimination of cytochrome bd oxidase branch via deleting gene cydB benefited bacitracin synthesis. Bacitracin titer and ATP content were increased by 10.97% and 22.96%, compared with those of original strain, respectively. Then, strengthening cytochrome aa3 oxidase branch via overexpressing gene qoxA was conducive to bacitracin production. Bacitracin titer and ATP content were increased by 18.97% and 34.00%, respectively. In addition, strengthening ADP synthesis supply is also proven as an effective strategy to promote intracellular ATP accumulation, overexpression of adenosine kinase DcK and adenylate kinase AdK could all improve bacitracin titers, among which, dck overexpression strain showed the better performance, and bacitracin titer was increased by 16.78%. Based on the above individual methods, a method of combining the deletion of gene cydB and overexpression of genes qoxA, dck were used to enhance ATP content of cells to 39.54 nmol/L, increased by 49.32% compared to original strain, and bacitracin titer produced by the final strain DW2-CQD (DW2ΔcydB::qoxA::dck) was 954.25 U/mL, increased by 21.66%. The bacitracin titer produced per cell was 2.11 U/CFU, increased by 11.05%. Collectively, this study demonstrates that improving ATP content was an efficient strategy to improve bacitracin production, and a promising strain B. licheniformis DW2-CQD was attained for industrial production of bacitracin.


Assuntos
Bacillus licheniformis , Bacitracina , Microbiologia Industrial , Bacillus licheniformis/metabolismo , Bacitracina/biossíntese , Metabolismo Energético/genética , Microbiologia Industrial/métodos
8.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1138-1149, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597063

RESUMO

Pyrroloquinoline quinone (PQQ), an important redox enzyme cofactor, has many physiological and biochemical functions, and is widely used in food, medicine, health and agriculture industry. In this study, PQQ production by recombinant Gluconobacter oxydans was investigated. First, to reduce the by-product of acetic acid, the recombinant strain G. oxydans T1 was constructed, in which the pyruvate decarboxylase (GOX1081) was knocked out. Then the pqqABCDE gene cluster and tldD gene were fused under the control of endogenous constitutive promoter P0169, to generate the recombinant strain G. oxydans T2. Finally, the medium composition and fermentation conditions were optimized. The biomass of G. oxydans T1 and G. oxydans T2 were increased by 43.02% and 38.76% respectively, and the PQQ production was 4.82 and 20.5 times higher than that of the wild strain, respectively. Furthermore, the carbon sources and culture conditions of G. oxydans T2 were optimized, resulting in a final PQQ yield of (51.32±0.899 7 mg/L), 345.6 times higher than that of the wild strain. In all, the biomass of G. oxydans and the yield of PQQ can be effectively increased by genetic engineering.


Assuntos
Gluconobacter oxydans , Microbiologia Industrial , Cofator PQQ , Fermentação , Técnicas de Inativação de Genes , Gluconobacter oxydans/genética , Gluconobacter oxydans/metabolismo , Microbiologia Industrial/métodos , Família Multigênica/genética , Organismos Geneticamente Modificados , Cofator PQQ/biossíntese , Cofator PQQ/genética , Regiões Promotoras Genéticas/genética
9.
Sheng Wu Gong Cheng Xue Bao ; 36(6): 1209-1215, 2020 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-32597070

RESUMO

Bioreactors have been central in monoclonal antibodies and vaccines manufacturing by mammalian cells in suspension culture. Numerical simulation of five impeller combinations in a stirred bioreactor was conducted, and characteristics of velocity vectors, distributions of gas hold-up, distributions of shear rate in the bioreactor using 5 impeller combinations were numerically elucidated. In addition, genetically engineered CHO cells were cultivated in bioreactor installed with 5 different impeller combinations in fed-batch culture mode. The cell growth and antibody level were directly related to the maximum shear rate in the bioreactor, and the highest viable cell density and the peak antibody level were achieved in FBMI3 impeller combination, indicating that CHO cells are sensitive to shear force produced by impeller movement when cells were cultivated in bioreactor at large scale, and the maximum shear rate would play key roles in scaling-up of bioreactor at industrial scale.


Assuntos
Técnicas de Cultura Celular por Lotes , Reatores Biológicos , Simulação por Computador , Microbiologia Industrial , Animais , Reatores Biológicos/normas , Células CHO , Contagem de Células , Cricetinae , Cricetulus , Microbiologia Industrial/instrumentação , Microbiologia Industrial/métodos
10.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 820-828, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567265

RESUMO

Corynebacterium glutamicum, an important microorganism to produce amino acids and organic acids, has been widely applied in food and medicine fields. Therefore, using editing tools to study the function of unknown genes in C. glutamicum has great significance for systematic development of industrial strain with efficient and novel production capability. Recently, gene editing has been greatly developed. Traditional gene editing based on homologous recombination and gene editing mediated by nuclease are successfully applied in C. glutamicum. Among these, the CRISPR system has been developed to be a main tool used for gene knockout of C. glutamicum due to its advantages of efficiency, simplicity and good target specificity. However, more efficient and reliable knockout system is still urgently demanded, to help develop high-performing strains in industrial application.


Assuntos
Corynebacterium glutamicum , Edição de Genes , Microbiologia Industrial , Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Corynebacterium glutamicum/genética , Edição de Genes/tendências , Ácido Glutâmico , Microbiologia Industrial/tendências
11.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 920-931, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567275

RESUMO

The capacity for thermal tolerance is critical for industrial enzyme. In the past decade, great efforts have been made to endow wild-type enzymes with higher catalytic activity or thermostability using gene engineering and protein engineering strategies. In this study, a recently developed SpyTag/SpyCatcher system, mediated by isopeptide bond-ligation, was used to modify a rumen microbiota-derived xylanase XYN11-6 as cyclized and stable enzyme C-XYN11-6. After incubation at 60, 70 or 80 ℃ for 10 min, the residual activities of C-XYN11-6 were 81.53%, 73.98% or 64.41%, which were 1.48, 2.92 or 3.98-fold of linear enzyme L-XYN11-6, respectively. After exposure to 60-90°C for 10 min, the C-XYN11-6 remained as soluble in suspension, while L-XYN11-6 showed severely aggregation. Intrinsic and 8-anilino-1-naphthalenesulfonic acid (ANS)-binding fluorescence analysis revealed that C-XYN11-6 was more capable of maintaining its conformation during heat challenge, compared with L-XYN11-6. Interestingly, molecular cyclization also conferred C-XYN11-6 with improved resilience to 0.1-50 mmol/L Ca²âº or 0.1 mmol/L Cu²âº treatment. In summary, we generated a thermal- and ion-stable cyclized enzyme using SpyTag/SpyCatcher system, which will be of particular interest in engineering of enzymes for industrial application.


Assuntos
Endo-1,4-beta-Xilanases , Estabilidade Enzimática , Microbiologia Industrial , Microbiota , Rúmen , Animais , Ciclização , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/metabolismo , Microbiologia Industrial/métodos , Engenharia de Proteínas , Rúmen/enzimologia , Rúmen/microbiologia , Temperatura
12.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 1002-1011, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567283

RESUMO

Uridine-cytidine kinase, an important catalyst in the compensation pathway of nucleotide metabolism, can catalyze the phosphorylation reaction of cytidine to 5'-cytidine monophosphate (CMP), but the reaction needs NTP as the phosphate donor. To increase the production efficiency of CMP, uridine-cytidine kinase gene from Thermus thermophilus HB8 and polyphosphate kinase gene from Rhodobacter sphaeroides were cloned and expressed in Escherichia coli BL21(DE3). Uridine-cytidine kinase was used for the generation of CMP from cytidine and ATP, and polyphosphate kinase was used for the regeneration of ATP. Then, the D403 metal chelate resin was used to adsorb Ni²âº to form an immobilized carrier, and the immobilized carrier was specifically combined with the recombinant enzymes to form the immobilized enzymes. Finally, single-factor optimization experiment was carried out to determine the reaction conditions of the immobilized enzyme. At 30 °C and pH 8.0, 60 mmol/L cytidine and 0.5 mmol/L ATP were used as substrates to achieve 5 batches of high-efficiency continuous catalytic reaction, and the average molar yield of CMP reached 91.2%. The above method has the advantages of low reaction cost, high product yield and high enzyme utilization rate, and has good applied value for industrial production.


Assuntos
Citidina Monofosfato , Microbiologia Industrial , Fosfotransferases (Aceptor do Grupo Fosfato) , Uridina Quinase , Citidina Monofosfato/metabolismo , Escherichia coli/genética , Microbiologia Industrial/métodos , Fosfotransferases (Aceptor do Grupo Fosfato)/metabolismo
13.
Pol J Microbiol ; 69(2): 193-203, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32548988

RESUMO

Microbial populations within the rhizosphere have been considered as prosperous repositories with respect to bioremediation aptitude. Among various environmental contaminants, effluent from textile industries holds a huge amount of noxious colored materials having high chemical oxygen demand concentrations causing ecological disturbances. The study was aimed to explore the promising mycobiome of rhizospheric soil for the degradation of azo dyes to develop an efficient system for the exclusion of toxic recalcitrants. An effluent sample from the textile industry and soil samples from the rhizospheric region of Musa acuminata and Azadirachta indica were screened for indigenous fungi to decolorize Congo red, a carcinogenic diazo dye, particularly known for its health hazards to the community. To develop a bio-treatment process, Aspergillus terreus QMS-1 was immobilized on pieces of Luffa cylindrica and exploited in stirred tank bioreactor under aerobic and optimized environment. Quantitative estimation of Congo red decolorization was carried out using UV-Visible spectrophotometer. The effects of fungal immobilization and biosorption on the native structure of Luffa cylindrica were evaluated using a scanning electron microscope. A. terreus QMS-1 can remove (92%) of the dye at 100 ppm within 24 h in the presence of 1% glucose and 1% ammonium sulphate at pH 5.0. The operation of the bioreactor in a continuous flow for 12 h with 100 ppm of Congo red dye in simulated textile effluent resulted in 97% decolorization. The stirred tank bioreactor was found to be a dynamic, well maintained, no sludge producing approach for the treatment of textile effluents by A. terreus QMS-1 of the significant potential for decolorization of Congo red.Microbial populations within the rhizosphere have been considered as prosperous repositories with respect to bioremediation aptitude. Among various environmental contaminants, effluent from textile industries holds a huge amount of noxious colored materials having high chemical oxygen demand concentrations causing ecological disturbances. The study was aimed to explore the promising mycobiome of rhizospheric soil for the degradation of azo dyes to develop an efficient system for the exclusion of toxic recalcitrants. An effluent sample from the textile industry and soil samples from the rhizospheric region of Musa acuminata and Azadirachta indica were screened for indigenous fungi to decolorize Congo red, a carcinogenic diazo dye, particularly known for its health hazards to the community. To develop a bio-treatment process, Aspergillus terreus QMS-1 was immobilized on pieces of Luffa cylindrica and exploited in stirred tank bioreactor under aerobic and optimized environment. Quantitative estimation of Congo red decolorization was carried out using UV-Visible spectrophotometer. The effects of fungal immobilization and biosorption on the native structure of Luffa cylindrica were evaluated using a scanning electron microscope. A. terreus QMS-1 can remove (92%) of the dye at 100 ppm within 24 h in the presence of 1% glucose and 1% ammonium sulphate at pH 5.0. The operation of the bioreactor in a continuous flow for 12 h with 100 ppm of Congo red dye in simulated textile effluent resulted in 97% decolorization. The stirred tank bioreactor was found to be a dynamic, well maintained, no sludge producing approach for the treatment of textile effluents by A. terreus QMS-1 of the significant potential for decolorization of Congo red.


Assuntos
Aspergillus/metabolismo , Reatores Biológicos/microbiologia , Vermelho Congo/isolamento & purificação , Microbiologia Industrial/métodos , Luffa/microbiologia , Microbiologia Industrial/economia , Rizosfera
14.
Arch Microbiol ; 202(7): 1907-1913, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32448962

RESUMO

In this work, volatile fatty acids (VFAs) were used as a carbon source to assess the ability of bacteria present in waste activated sludge (WAS), as indigenous flora, to accumulate polyhydroxyalkanoates (PHA). Acetic acid and propionic acid were used both separately and in combination as feedstock, producing either homopolymer poly(3-hydroxybutyrate) (3PHB) and/or the co-polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV). The overall potential to use waste activated sludge as biomass for production of valuable polymers was assessed, and a quality assessment of the as-produced polymers was run, with the extracted polymer being analyzed for properties such as thermal, microstructure and molecular weight. It was found that a blend of copolymers was typically produced, with thermal properties being similar to those reported elsewhere. The overall PHA cell content obtained was 0.29 gPHA gVSS-1.


Assuntos
Biomassa , Microbiologia Industrial , Poli-Hidroxialcanoatos/metabolismo , Esgotos/microbiologia , Carbono/metabolismo , Ácidos Graxos Voláteis , Peso Molecular , Poli-Hidroxialcanoatos/biossíntese , Poli-Hidroxialcanoatos/química
15.
Arch Microbiol ; 202(7): 1597-1615, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32451592

RESUMO

Extracellular enzymes produced from Streptomyces have the potential to replace toxic chemicals that are being used in various industries. The endorsement of this replacement has not received a better platform in developing countries. In this review, we have discussed the impact of chemicals and conventional practices on environmental health, and the role of extracellular enzymes to replace these practices. Burning of fossil fuels and agriculture residue is a global issue, but the production of biofuel using extracellular enzymes may be the single key to solve all these issues. We have discussed the replacement of hazardous chemicals with the use of xylanase, cellulase, and pectinase in food industries. In paper industries, delignification was done by the chemical treatment, but xylanase and laccase have the efficient potential to remove the lignin from pulp. In textile industries, the conventional method includes the chemicals which affect the nervous system and other organs. The use of xylanase, cellulase, and pectinase in different processes can give a safe and environment-friendly option to textile industries. Hazardous chemical pesticides can be replaced by the use of chitinase as an insecticide and fungicide in agricultural practices.


Assuntos
Proteínas de Bactérias/metabolismo , Enzimas/metabolismo , Microbiologia Industrial/tendências , Streptomyces/enzimologia , Agricultura , Biocombustíveis , Lignina/metabolismo
16.
PLoS One ; 15(5): e0229889, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32396555

RESUMO

The purpose of the study involves the development of an anaerobic, thermophilic microbial consortium TERIK from the high temperature reservoir of Gujarat for enhance oil recovery. To isolate indigenous microbial consortia, anaerobic baltch media were prepared and inoculated with the formation water; incubated at 65°C for 10 days. Further, the microbial metabolites were analyzed by gas chromatography, FTIR and surface tension. The efficiency of isolated consortia towards enhancing oil recovery was analyzed through core flood assay. The novelty of studied consortia was that, it produces biomass (600 mg/l), bio-surfactant (325 mg/l), and volatile fatty acids (250 mg/l) at 65°C in the span of 10 days, that are adequate to alter the surface tension (70 to 34 mNm -1) and sweep efficiency of zones facilitating the displacement of oil. TERIK was identified as Clostridium sp. The FTIR spectra of biosurfactant indicate the presence of N-H stretch, amides and polysaccharide. A core flooding assay was designed to explore the potential of TERIK towards enhancing oil recovery. The results showed an effective reduction in permeability at residual oil saturation from 2.14 ± 0.1 to 1.39 ± 0.05 mD and 19% incremental oil recovery.


Assuntos
Archaea/metabolismo , Microbiologia Industrial , Consórcios Microbianos , Campos de Petróleo e Gás/microbiologia , Clostridium/metabolismo , Temperatura Alta , Humanos , Petróleo/microbiologia , Tensão Superficial , Tensoativos/farmacologia
17.
J Biosci Bioeng ; 130(2): 200-204, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32389469

RESUMO

Ectoine is a zwitterionic amino acid derivative that can be naturally sourced from halophilic microorganisms. The increasing demands of ectoine in various industries have urged the researches on the cost-effective approaches on production of ectoine. Ionic liquids-based aqueous biphasic system (ILABS) was applied to recover Halomonas salina ectoine from cells hydrolysate. The 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim)BF4 was used in the ILABS and the recovery efficiency of ILABS to recover ectoine from H. salina cells lysate was evaluated by determining the effects of phase composition; pHs; crude loading and additional neutral salt (NaCl). The hydrophilic ectoine was targeted to partition to the hydrophilic salt-rich phase. A total yield (YB) of 96.32% ± 1.08 of ectoine was obtained with ILABS of phase composition of 20% (w/w) (Bmim)BF4 and 30% (w/w) sulfate salts; system pH of 5.5 when the 20% (w/w) of crude feedstock was applied to the ILABS. There was no significant enhancement on the ectoine recovery efficiency using the ILABS when NaCl was added, therefore the ILABS composition without the additional neutral salt was recommended for the primary purification of ectoine. Partition coefficient (KE) of 30.80 ± 0.42, purity (PE) of 95.82% and enrichment factor (Ef) of 1.92 were recorded with the optimum (Bmim)BF4/sulfate ILABS. These findings have provided an insight on the feasibility of recovery of intracellular biomolecules using the green solvent-based aqueous system in one single-step operation.


Assuntos
Diamino Aminoácidos/isolamento & purificação , Halomonas/química , Microbiologia Industrial/métodos , Líquidos Iônicos/química , Água/química , Imidazóis , Microbiologia Industrial/economia , Cloreto de Sódio/química
18.
World J Microbiol Biotechnol ; 36(5): 75, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32390104

RESUMO

Biofilm reactors retain microbial cells in the form of biofilm which is attached to free moving or fixed carrying materials, thus providing a high active biomass concentration and automatic liquid and solid separation. Nowadays, microbial biofilm reactors have been widely used in high-strength wastewater treatment where very high pollutant removal efficiency is required, which usually requires excessive space and aeration energy for conventional activated sludge-based treatment. This paper provides an overview of microbial biofilm reactors developed over the last half-century, including moving bed biofilm reactor (MBBR), trickling filter (TF) reactor, rotating biological contactor (RBC), membrane biofilm reactor (MBfR), passive aeration simultaneous nitrification and denitrification (PASND) biofilm reactor, for their applications in high-strength wastewater treatment of not only removing carbon, nitrogen, sulphur but also a variety of oxidized contaminants including perchlorate and bromate. Despite the advance of biofilm reactor that exhibits high resistance to excessive pollutants loading, its drawbacks both from engineering and microbiological point of view are reviewed. The future prospects of biofilm reactor are also discussed in this review paper.


Assuntos
Biofilmes , Reatores Biológicos/microbiologia , Águas Residuárias/microbiologia , Purificação da Água/métodos , Biomassa , Bromatos/metabolismo , Carbono/metabolismo , Desnitrificação , Microbiologia Industrial , Membranas , Nitrificação , Nitrogênio , Percloratos/metabolismo , Esgotos/microbiologia
19.
J Biosci Bioeng ; 130(2): 159-165, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32418725

RESUMO

Soaking is an important process in Chinese rice wine brewing. In this study, the influence of vacuum soaking on Chinese rice wine production was investigated. Rice subjected to a 1-h vacuum soaking process or a traditional 2-days soaking process was steamed and fermented. Our results showed that vacuum soaking led to similar absorbed water but less leached solids compared with traditional soaking and showed limited influence on the physiochemical characteristics of steamed rice. Monitoring of the fermentation process suggested that the content of amino acid nitrogen in the vacuum-soaked group was significantly higher than that of the traditional-soaked group, while the other indexes were similar. The detection of flavor substances in the rice wine indicated that the contents of organic acids and free amino acids were higher in the vacuum-soaked group, and the main kinds of volatile flavor compounds from the two groups were similar. Additionally, sensory evaluation reflected that the rice wine brewed with rice subjected to either of the two different soaking treatments had similar sensory performances. Our research indicated that vacuum soaking could effectively shorten the soaking time of rice in Chinese rice wine production, thus shortening the brewing cycle without sacrificing the quality of the rice wine.


Assuntos
Manipulação de Alimentos/métodos , Microbiologia Industrial/métodos , Oryza/química , Vapor , Vácuo , Vinho/normas , Ácidos/análise , Fermentação , Aromatizantes/análise , Nitrogênio/análise , Oryza/metabolismo , Paladar , Vinho/microbiologia
20.
J Biosci Bioeng ; 130(2): 195-199, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32370929

RESUMO

Ectoine production using inexpensive and renewable biomass resources has attracted great interest among the researchers due to the low yields of ectoine in current fermentation approaches that complicate the large-scale production of ectoine. In this study, ectoine was produced from corn steep liquor (CSL) and soybean hydrolysate (SH) in replacement to yeast extract as the nitrogen sources for the fermentation process. To enhance the bacterial growth and ectoine production, biotin was added to the Halomonas salina fermentation media. In addition, the effects addition of surfactants such as Tween 80 and saponin on the ectoine production were also investigated. Results showed that both the CSL and SH can be used as the nitrogen source substitutes in the fermentation media. Higher amount of ectoine (1781.9 mg L-1) was produced in shake flask culture with SH-containing media as compared to CSL-containing media. A total of 2537.0 mg L-1 of ectoine was produced at pH 7 when SH-containing media was applied in the 2 L batch fermentation. Moreover, highest amount of ectoine (1802.0 mg L-1) was recorded in the SH-containing shake flask culture with addition of 0.2 µm mL-1 biotin. This study demonstrated the efficacy of industrial waste as the nutrient supplement for the fermentation of ectoine production.


Assuntos
Diamino Aminoácidos/metabolismo , Fermentação , Halomonas/metabolismo , Microbiologia Industrial/métodos , Técnicas de Cultura Celular por Lotes , Biomassa , Biotina/metabolismo , Meios de Cultura/química , Meios de Cultura/metabolismo , Resíduos Industriais , Nitrogênio/metabolismo , Soja/química , Zea mays/química
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