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Kim SH, Singh D, Kim SA, Kwak MJ, Cho D, Kim J, Roh JH, Kim WG, Han NS, Lee CH. Strain-specific metabolomic diversity of Lactiplantibacillus plantarum under aerobic and anaerobic conditions. Food Microbiol 2023; 116:104364. [PMID: 37689426 DOI: 10.1016/j.fm.2023.104364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/31/2023] [Accepted: 08/11/2023] [Indexed: 09/11/2023]
Abstract
The chemotaxonomic diversity of 20 Lactiplantibacillus plantarum strains was investigated using non-targeted metabolite profiling under different culture conditions. Multivariate and metabolic pathway analyses based on GC-MS and LC-MS/MS datasets showed that amino acid metabolism, especially 2-hydroxy acids, was enriched under aerobic conditions (AE), whereas fatty acid & sugar metabolism was increased under anaerobic conditions (AN). Based on the metabolite profiles, L. plantarum strains were clustered into three main groups (A, B, and C). Overall, 79 and 83 significantly discriminant metabolites were characterized as chemical markers of AE and AN growth conditions, respectively. Notably, alcohols were more abundant in group A whereas amino acids, peptides, purines, and pyrimidines were significantly higher in group C. 2-hydroxy acids and oxylipins biosynthesized through amino acid and fatty acid metabolism, respectively, were more abundant in groups A and B. Furthermore, we observed a strong correlation between the chemical diversity of L. plantarum groups and their antioxidant activity from metabolite extracts. We propose a non-targeted metabolomic workflow to comprehensively characterize the chemodiversity of L. plantarum strain under different culture conditions, which may help reveal specific biomarkers of individual strains depending on the culture conditions.
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Affiliation(s)
- Su-Hyun Kim
- Department of Bioscience and Biotechnology, Konkuk University, 05029, Seoul, Republic of Korea
| | - Digar Singh
- Department of Bioscience and Biotechnology, Konkuk University, 05029, Seoul, Republic of Korea
| | - Seul-Ah Kim
- Brain Korea 21 Center for Bio-Health Industry, Division of Animal, Horticultural, And Food Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Min Jeong Kwak
- Brain Korea 21 Center for Bio-Health Industry, Division of Animal, Horticultural, And Food Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Donghyun Cho
- Amorepacific R&I Center, 1920, Yonggu-daero, Yongin, 17074, Republic of Korea
| | - Juewon Kim
- Amorepacific R&I Center, 1920, Yonggu-daero, Yongin, 17074, Republic of Korea
| | - Jong-Hwa Roh
- Amorepacific R&I Center, 1920, Yonggu-daero, Yongin, 17074, Republic of Korea
| | - Wan-Gi Kim
- Amorepacific R&I Center, 1920, Yonggu-daero, Yongin, 17074, Republic of Korea
| | - Nam Soo Han
- Brain Korea 21 Center for Bio-Health Industry, Division of Animal, Horticultural, And Food Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea
| | - Choong Hwan Lee
- Department of Bioscience and Biotechnology, Konkuk University, 05029, Seoul, Republic of Korea; Research Institute for Bioactive-Metabolome Network, Konkuk University, Seoul, Republic of Korea.
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Li Y, Zhao X, Yao M, Yang W, Han Y, Liu L, Zhang J, Liu J. Mechanism of microbial production of acetoin and 2,3-butanediol optical isomers and substrate specificity of butanediol dehydrogenase. Microb Cell Fact 2023; 22:165. [PMID: 37644496 PMCID: PMC10466699 DOI: 10.1186/s12934-023-02163-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/31/2023] [Indexed: 08/31/2023] Open
Abstract
3-Hydroxybutanone (Acetoin, AC) and 2,3-butanediol (BD) are two essential four-carbon platform compounds with numerous pharmaceutical and chemical synthesis applications. AC and BD have two and three stereoisomers, respectively, while the application of the single isomer product in chemical synthesis is superior. AC and BD are glucose overflow metabolites produced by biological fermentation from a variety of microorganisms. However, the AC or BD produced by microorganisms using glucose is typically a mixture of various stereoisomers. This was discovered to be due to the simultaneous presence of multiple butanediol dehydrogenases (BDHs) in microorganisms, and AC and BD can be interconverted under BDH catalysis. In this paper, beginning with the synthesis pathways of microbial AC and BD, we review in detail the studies on the formation mechanisms of different stereoisomers of AC and BD, summarize the properties of different types of BDH that have been tabulated, and analyze the structural characteristics and affinities of different types of BDH by comparing them using literature and biological database data. Using microorganisms, recent research on the production of optically pure AC or BD was also reviewed. Limiting factors and possible solutions for chiral AC and BD production are discussed.
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Affiliation(s)
- Yuchen Li
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Xiangying Zhao
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China.
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China.
| | - Mingjing Yao
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
| | - Wenli Yang
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Yanlei Han
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
| | - Liping Liu
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Jiaxiang Zhang
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
| | - Jianjun Liu
- Shandong Food Ferment Industry Research & Design Institute, Qilu University of Technology, Shandong Academy of Sciences), Jinan, 250013, China
- School of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, China
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Prasad SV, Fiedoruk K, Zakrzewska M, Savage PB, Bucki R. Glyoxylate Shunt and Pyruvate-to-Acetoin Shift Are Specific Stress Responses Induced by Colistin and Ceragenin CSA-13 in Enterobacter hormaechei ST89. Microbiol Spectr 2023; 11:e0121523. [PMID: 37338344 PMCID: PMC10434160 DOI: 10.1128/spectrum.01215-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023] Open
Abstract
Ceragenins, including CSA-13, are cationic antimicrobials that target the bacterial cell envelope differently than colistin. However, the molecular basis of their action is not fully understood. Here, we examined the genomic and transcriptome responses by Enterobacter hormaechei after prolonged exposure to either CSA-13 or colistin. Resistance of the E. hormaechei 4236 strain (sequence type 89 [ST89]) to colistin and CSA-13 was induced in vitro during serial passages with sublethal doses of tested agents. The genomic and metabolic profiles of the tested isolates were characterized using a combination of whole-genome sequencing (WGS) and transcriptome sequencing (RNA-seq), followed by metabolic mapping of differentially expressed genes using Pathway Tools software. The exposure of E. hormaechei to colistin resulted in the deletion of the mgrB gene, whereas CSA-13 disrupted the genes encoding an outer membrane protein C and transcriptional regulator SmvR. Both compounds upregulated several colistin-resistant genes, such as the arnABCDEF operon and pagE, including genes coding for DedA proteins. The latter proteins, along with beta-barrel protein YfaZ and VirK/YbjX family proteins, were the top overexpressed cell envelope proteins. Furthermore, the l-arginine biosynthesis pathway and putrescine-ornithine antiporter PotE were downregulated in both transcriptomes. In contrast, the expression of two pyruvate transporters (YhjX and YjiY) and genes involved in pyruvate metabolism, as well as genes involved in generating proton motive force (PMF), was antimicrobial specific. Despite the similarity of the cell envelope transcriptomes, distinctly remodeled carbon metabolism (i.e., toward fermentation of pyruvate to acetoin [colistin] and to the glyoxylate pathway [CSA-13]) distinguished both antimicrobials, which possibly reflects the intensity of the stress exerted by both agents. IMPORTANCE Colistin and ceragenins, like CSA-13, are cationic antimicrobials that disrupt the bacterial cell envelope through different mechanisms. Here, we examined the genomic and transcriptome changes in Enterobacter hormaechei ST89, an emerging hospital pathogen, after prolonged exposure to these agents to identify potential resistance mechanisms. Interestingly, we observed downregulation of genes associated with acid stress response as well as distinct dysregulation of genes involved in carbon metabolism, resulting in a switch from pyruvate fermentation to acetoin (colistin) and the glyoxylate pathway (CSA-13). Therefore, we hypothesize that repression of the acid stress response, which alkalinizes cytoplasmic pH and, in turn, suppresses resistance to cationic antimicrobials, could be interpreted as an adaptation that prevents alkalinization of cytoplasmic pH in emergencies induced by colistin and CSA-13. Consequently, this alteration critical for cell physiology must be compensated via remodeling carbon and/or amino acid metabolism to limit acidic by-product production.
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Affiliation(s)
- Suhanya V. Prasad
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland
| | - Krzysztof Fiedoruk
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland
| | - Magdalena Zakrzewska
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland
| | - Paul B. Savage
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah, USA
| | - Robert Bucki
- Department of Medical Microbiology and Nanobiomedical Engineering, Medical University of Bialystok, Bialystok, Poland
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Goldmanns J, Röhling GA, Lipa MK, Scholand T, Deitert A, May T, Haas EP, Boy M, Herold A, Büchs J. Development of a chemically defined medium for Paenibacillus polymyxa by parallel online monitoring of the respiration activity in microtiter plates. BMC Biotechnol 2023; 23:25. [PMID: 37507713 PMCID: PMC10385886 DOI: 10.1186/s12896-023-00793-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND One critical parameter in microbial cultivations is the composition of the cultivation medium. Nowadays, the application of chemically defined media increases, due to a more defined and reproducible fermentation performance than in complex media. In order, to improve cost-effectiveness of fermentation processes using chemically defined media, the media should not contain nutrients in large excess. Additionally, to obtain high product yields, the nutrient concentrations should not be limiting. Therefore, efficient medium optimization techniques are required which adapt medium compositions to the specific nutrient requirements of microorganisms. RESULTS Since most Paenibacillus cultivation protocols so far described in literature are based on complex ingredients, in this study, a chemically defined medium for an industrially relevant Paenibacillus polymyxa strain was developed. A recently reported method, which combines a systematic experimental procedure in combination with online monitoring of the respiration activity, was applied and extended to identify growth limitations for Paenibacillus polymyxa. All cultivations were performed in microtiter plates. By systematically increasing the concentrations of different nutrient groups, nicotinic acid was identified as a growth-limiting component. Additionally, an insufficient buffer capacity was observed. After optimizing the growth in the chemically defined medium, the medium components were systematically reduced to contain only nutrients relevant for growth. Vitamins were reduced to nicotinic acid and biotin, and amino acids to methionine, histidine, proline, arginine, and glutamate. Nucleobases/-sides could be completely left out of the medium. Finally, the cultivation in the reduced medium was reproduced in a laboratory fermenter. CONCLUSION In this study, a reliable and time-efficient high-throughput methodology was extended to investigate limitations in chemically defined media. The interpretation of online measured respiration activities agreed well with the growth performance of samples measured in parallel via offline analyses. Furthermore, the cultivation in microtiter plates was validated in a laboratory fermenter. The results underline the benefits of online monitoring of the respiration activity already in the early stages of process development, to avoid limitations of medium components, oxygen limitation and pH inhibition during the scale-up.
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Affiliation(s)
- Jennifer Goldmanns
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Georg Andreas Röhling
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Marie Kristine Lipa
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Theresa Scholand
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Alexander Deitert
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany
| | - Tobias May
- BASF SE, Carl-Bosch-Straße 38, Ludwigshafen am Rhein, 67056, Germany
| | | | - Matthias Boy
- BASF SE, Carl-Bosch-Straße 38, Ludwigshafen am Rhein, 67056, Germany
| | - Andrea Herold
- BASF SE, Carl-Bosch-Straße 38, Ludwigshafen am Rhein, 67056, Germany
| | - Jochen Büchs
- RWTH Aachen University, AVT - Biochemical Engineering, Forckenbeckstraße 51, 52074, Aachen, Germany.
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Li R, Tao J, Huang D, Zhou W, Gao L, Wang X, Chen H, Huang H. Investigating the effects of biodegradable microplastics and copper ions on probiotic (Bacillus amyloliquefaciens): Toxicity and application. JOURNAL OF HAZARDOUS MATERIALS 2023; 443:130081. [PMID: 36367472 DOI: 10.1016/j.jhazmat.2022.130081] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/13/2022] [Accepted: 09/26/2022] [Indexed: 06/16/2023]
Abstract
Currently, microplastic pollution is more serious and complicates the toxic effects of other co-existing pollutants in the environment. However, the effect and mechanism of biodegradable plastics on the growth and metabolism of probiotic remain unclear. This work selected Bacillus amyloliquefaciens as model bacterium for a three-day exposure experiment to probe the issues. The results showed that 100 mg/L polylactic acid microplastics (PLA MPs) (3-4 mm, flake shape) caused oxidative damage to cell membranes, disrupted cell wall composition and inhibited cell growth by 21.2-27.5 %. The toxicity was not simply additive or synergistic effects when PLA MPs (100 mg/L) and copper ions (10 mg/L) coexisted. PLA MPs did not significantly increase the toxicity of copper to bacteria, instead triggered some mechanisms to resist the toxicity of copper. The bacteria formed spores to resist PLA MPs, while the copper ions toxicity was weaken by chelation and efflux. It is worth noting that copper ions instead increased the expression of genes related fengycin and iturin then improving the bacteriostatic activity of the probiotic. This paper deeply analyzes the toxicity mechanism of combined pollution on Bacillus amyloliquefacien, and also provides new perspective for helping to inhibit pathogenic bacteria under biodegradable microplastics and metal stress.
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Affiliation(s)
- Ruijin Li
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Jiaxi Tao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Danlian Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China.
| | - Wei Zhou
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Lan Gao
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Xinya Wang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Haojie Chen
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
| | - Hai Huang
- College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082, PR China
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Metabolic Engineering of Microorganisms to Produce Pyruvate and Derived Compounds. Molecules 2023; 28:molecules28031418. [PMID: 36771084 PMCID: PMC9919917 DOI: 10.3390/molecules28031418] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/27/2023] [Accepted: 01/29/2023] [Indexed: 02/05/2023] Open
Abstract
Pyruvate is a hub of various endogenous metabolic pathways, including glycolysis, TCA cycle, amino acid, and fatty acid biosynthesis. It has also been used as a precursor for pyruvate-derived compounds such as acetoin, 2,3-butanediol (2,3-BD), butanol, butyrate, and L-alanine biosynthesis. Pyruvate and derivatives are widely utilized in food, pharmaceuticals, pesticides, feed additives, and bioenergy industries. However, compounds such as pyruvate, acetoin, and butanol are often chemically synthesized from fossil feedstocks, resulting in declining fossil fuels and increasing environmental pollution. Metabolic engineering is a powerful tool for producing eco-friendly chemicals from renewable biomass resources through microbial fermentation. Here, we review and systematically summarize recent advances in the biosynthesis pathways, regulatory mechanisms, and metabolic engineering strategies for pyruvate and derivatives. Furthermore, the establishment of sustainable industrial synthesis platforms based on alternative substrates and new tools to produce these compounds is elaborated. Finally, we discuss the potential difficulties in the current metabolic engineering of pyruvate and derivatives and promising strategies for constructing efficient producers.
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Sun Y, Kokko M, Vassilev I. Anode-assisted electro-fermentation with Bacillus subtilis under oxygen-limited conditions. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:6. [PMID: 36627716 PMCID: PMC9832610 DOI: 10.1186/s13068-022-02253-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023]
Abstract
BACKGROUND Bacillus subtilis is generally regarded as a ubiquitous facultative anaerobe. Oxygen is the major electron acceptor of B. subtilis, and when oxygen is absent, B. subtilis can donate electrons to nitrate or perform fermentation. An anode electrode can also be used by microorganisms as the electron sink in systems called anodic electro-fermentation. The facultative anaerobic character of B. subtilis makes it an excellent candidate to explore with different electron acceptors, such as an anode. This study aimed to optimise industrial aerobic bioprocesses using alternative electron acceptors. In particular, different end product spectrum of B. subtilis with various electron acceptors, including anode from the electro-fermentation system, was investigated. RESULTS B. subtilis was grown using three electron acceptors, i.e. oxygen, nitrate and anode (poised at a potential of 0.7 V vs. standard hydrogen electrode). The results showed oxygen had a crucial role for cells to remain metabolically active. When nitrate or anode was applied as the sole electron acceptor anaerobically, immediate cell lysis and limited glucose consumption were observed. In anode-assisted electro-fermentation with a limited aeration rate, acetoin, as the main end product showed the highest yield of 0.78 ± 0.04 molproduct/molglucose, two-fold higher than without poised potential (0.39 ± 0.08 molproduct/molglucose). CONCLUSIONS Oxygen controls B. subtilis biomass growth, alternative electron acceptors utilisation and metabolites formation. Limited oxygen/air supply enabled the bacteria to donate excess electrons to nitrate or anode, leading to steered product spectrum. The anode-assisted electro-fermentation showed its potential to boost acetoin production for future industrial biotechnology applications.
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Affiliation(s)
- Yu Sun
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Marika Kokko
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
| | - Igor Vassilev
- grid.502801.e0000 0001 2314 6254Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 8, 33720 Tampere, Finland
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Barbato M, Palma E, Marzocchi U, Cruz Viggi C, Rossetti S, Aulenta F, Scoma A. Snorkels enhance alkanes respiration at ambient and increased hydrostatic pressure (10 MPa) by either supporting the TCA cycle or limiting alternative routes for acetyl-CoA metabolism. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115244. [PMID: 35598451 DOI: 10.1016/j.jenvman.2022.115244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/27/2022] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The impact of piezosensitive microorganisms is generally underestimated in the ecology of underwater environments exposed to increasing hydrostatic pressure (HP), including the biodegradation of crude oil components. Yet, no isolated pressure-loving (piezophile) microorganism grows optimally on hydrocarbons, and no isolated piezophile at all has a HP optimum <10 MPa (e.g. 1000 m below sea water level). Piezosensitive heterotrophs are thus largely accountable for oil clean up < 10 MPa, however, they are affected by such a mild HP increase in ways which are not completely clear. In a first study, the application of a bioelectrochemical system (called "oil-spill snorkel") enhanced the alkane oxidation capacity in sediments collected at surface water but tested up to 10 MPa. Here, the fingerprint left on transcript abundance was studied to explore which metabolic routes are 1) supported by snorkels application and 2) negatively impacted by HP increase. Transcript abundance was comparable for beta-oxidation across all treatments (also at a taxonomical level), while the metabolism of acetyl-CoA was highly impacted: at either 0.1 or 10 MPa, snorkels supported acetyl-CoA oxidation within the TCA cycle, while in negative controls using non-conductive rods several alternative routes for acetyl-CoA were stimulated (including those leading to internal carbon reserves e.g. 2,3 butanediol and dihydroxyacetone). In general, increased HP had opposite effects as compared to snorkels, thus indicating that snorkels could enhance hydrocarbons oxidation by alleviating in part the stressing effects imposed by increased HP on the anaerobic, respiratory electron transport chain. 16S rRNA gene analysis of sediments and biofilms on snorkels suggest a crosstalk between oil-degrading, sulfate-reducing microorganisms and sulfur oxidizers. In fact, no sulfur was deposited on snorkels, however, iron, aluminum and phosphorous were found to preferentially deposit on snorkels at 10 MPa. This data indicates that a passive BES such as the oil-spill snorkel can mitigate the stress imposed by increased HP on piezosensitive microorganisms (up to 10 MPa) without being subjected to passivation. An improved setup applying these principles can further support this deep-sea bioremediation strategy.
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Affiliation(s)
- Marta Barbato
- Engineered Microbial Systems (EMS) Lab, Industrial Biotechnology Section, Department of Biological and Chemical Engineering (BCE), Aarhus University, Aarhus, Denmark; Microbiology Section, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Enza Palma
- Water Research Institute (IRSA), National Research Council (CNR), Monterotondo, Italy
| | - Ugo Marzocchi
- Center for Electromicrobiology, Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark; Center for Water Technology WATEC, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Carolina Cruz Viggi
- Water Research Institute (IRSA), National Research Council (CNR), Monterotondo, Italy
| | - Simona Rossetti
- Water Research Institute (IRSA), National Research Council (CNR), Monterotondo, Italy
| | - Federico Aulenta
- Water Research Institute (IRSA), National Research Council (CNR), Monterotondo, Italy.
| | - Alberto Scoma
- Engineered Microbial Systems (EMS) Lab, Industrial Biotechnology Section, Department of Biological and Chemical Engineering (BCE), Aarhus University, Aarhus, Denmark; Microbiology Section, Department of Biology, Aarhus University, Aarhus, Denmark.
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Genome-Wide Association Study Reveals Host Factors Affecting Conjugation in Escherichia coli. Microorganisms 2022; 10:microorganisms10030608. [PMID: 35336183 PMCID: PMC8954029 DOI: 10.3390/microorganisms10030608] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/08/2022] [Accepted: 03/10/2022] [Indexed: 02/04/2023] Open
Abstract
The emergence and dissemination of antibiotic resistance threaten the treatment of common bacterial infections. Resistance genes are often encoded on conjugative elements, which can be horizontally transferred to diverse bacteria. In order to delay conjugative transfer of resistance genes, more information is needed on the genetic determinants promoting conjugation. Here, we focus on which bacterial host factors in the donor assist transfer of conjugative plasmids. We introduced the broad-host-range plasmid pKJK10 into a diverse collection of 113 Escherichia coli strains and measured by flow cytometry how effectively each strain transfers its plasmid to a fixed E. coli recipient. Differences in conjugation efficiency of up to 2.7 and 3.8 orders of magnitude were observed after mating for 24 h and 48 h, respectively. These differences were linked to the underlying donor strain genetic variants in genome-wide association studies, thereby identifying candidate genes involved in conjugation. We confirmed the role of fliF, fliK, kefB and ucpA in the donor ability of conjugative elements by validating defects in the conjugation efficiency of the corresponding lab strain single-gene deletion mutants. Based on the known cellular functions of these genes, we suggest that the motility and the energy supply, the intracellular pH or salinity of the donor affect the efficiency of plasmid transfer. Overall, this work advances the search for targets for the development of conjugation inhibitors, which can be administered alongside antibiotics to more effectively treat bacterial infections.
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Mechanisms of Acetoin Toxicity and Adaptive Responses in an Acetoin-Producing Species, Lactococcus lactis. Appl Environ Microbiol 2021; 87:e0107921. [PMID: 34613757 PMCID: PMC8612267 DOI: 10.1128/aem.01079-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Acetoin, 3-hydroxyl,2-butanone, is extensively used as a flavor additive in food products. This volatile compound is produced by the dairy bacterium Lactococcus lactis when aerobic respiration is activated by haem addition, and comprises ∼70% of carbohydrate degradation products. Here we investigate the targets of acetoin toxicity, and determine how acetoin impacts L. lactis physiology and survival. Acetoin caused damage to DNA and proteins, which related to reactivity of its keto group. Acetoin stress was reflected in proteome profiles, which revealed changes in lipid metabolic proteins. Acetoin provoked marked changes in fatty acid composition, with massive accumulation of cycC19:0 cyclopropane fatty acid at the expense of its unsaturated C18:1 fatty acid precursor. Deletion of the cfa gene, encoding the cycC19:0 synthase, sensitized cells to acetoin stress. Acetoin-resistant transposon mutagenesis revealed a hot spot in the high affinity phosphate transporter operon pstABCDEF, which is known to increase resistance to multiple stresses. This work reveals the causes and consequences of acetoin stress on L. lactis, and may facilitate control of lactic acid bacteria production in technological processes. IMPORTANCE Acetoin, 3-hydroxyl,2-butanone, has diverse uses in chemical industry, agriculture, and dairy industries as a volatile compound that generates aromas. In bacteria, it can be produced in high amount by Lactococcus lactis when it grows under aerobic respiration. However, acetoin production can be toxic and detrimental for growth and/or survival. Our results showed that it damages DNA and proteins via its keto group. We also showed that acetoin modifies membrane fatty acid composition with the production of cyclopropane C19:0 fatty acid at the expense of an unsaturated C18:1. We isolated mutants more resistant to acetoin than the wild-type strain. All of them mapped to a single locus pstABCDEF operon, suggesting a simple means to limit acetoin toxicity in dairy bacteria and to improve its production.
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Lee JW, Lee YG, Jin YS, Rao CV. Metabolic engineering of non-pathogenic microorganisms for 2,3-butanediol production. Appl Microbiol Biotechnol 2021; 105:5751-5767. [PMID: 34287658 DOI: 10.1007/s00253-021-11436-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022]
Abstract
2,3-Butanediol (2,3-BDO) is a promising commodity chemical with various industrial applications. While petroleum-based chemical processes currently dominate the industrial production of 2,3-BDO, fermentation-based production of 2,3-BDO provides an attractive alternative to chemical-based processes with regards to economic and environmental sustainability. The achievement of high 2,3-BDO titer, yield, and productivity in microbial fermentation is a prerequisite for the production of 2,3-BDO at large scales. Also, enantiopure production of 2,3-BDO production is desirable because 2,3-BDO stereoisomers have unique physicochemical properties. Pursuant to these goals, many metabolic engineering strategies to improve 2,3-BDO production from inexpensive sugars by Klebsiella oxytoca, Bacillus species, and Saccharomyces cerevisiae have been developed. This review summarizes the recent advances in metabolic engineering of non-pathogenic microorganisms to enable efficient and enantiopure production of 2,3-BDO. KEY POINTS: • K. oxytoca, Bacillus species, and S. cerevisiae have been engineered to achieve efficient 2,3-BDO production. • Metabolic engineering of non-pathogenic microorganisms enabled enantiopure production of 2,3-BDO. • Cost-effective 2,3-BDO production can be feasible by using renewable biomass.
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Affiliation(s)
- Jae Won Lee
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Ye-Gi Lee
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Christopher V Rao
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. .,Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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Markkinen N, Pariyani R, Jokioja J, Kortesniemi M, Laaksonen O, Yang B. NMR-based metabolomics approach on optimization of malolactic fermentation of sea buckthorn juice with Lactiplantibacillus plantarum. Food Chem 2021; 366:130630. [PMID: 34333181 DOI: 10.1016/j.foodchem.2021.130630] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 12/17/2022]
Abstract
This work investigated the impact of malolactic fermentation on the metabolomic profile of sea buckthorn juice to optimize the fermentation process for flavor modification. Six strains of L. plantarum were used with varied pH of the juice, cell acclimation, and fermentation time. 1H-NOESY spectra were acquired from fresh and fermented juices with a total of 46 metabolites identified. Less sugars and quinic acid were metabolized at pH 2.7 while oxidation of ascorbic acid was reduced at pH 3.5. l-Malic acid, essential amino acids, and nucleosides were consumed early during fermentation while sugars in general were consumed later in the fermentation. If deacidification is the main target of fermentation, strains that produce less acids and ferment less sugars, shorter fermentation time, and lower starter pH should be used. Higher starter pH and longer fermentation time promote formation of antimicrobial compounds and potentially increase antioxidant stability.
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Affiliation(s)
- N Markkinen
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland.
| | - R Pariyani
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland
| | - J Jokioja
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland
| | - M Kortesniemi
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland
| | - O Laaksonen
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland
| | - B Yang
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turun yliopisto, Finland
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Horlbog JA, Stevens MJA, Stephan R, Guldimann C. Global Transcriptional Response of Three Highly Acid-Tolerant Field Strains of Listeria monocytogenes to HCl Stress. Microorganisms 2019; 7:microorganisms7100455. [PMID: 31623206 PMCID: PMC6843411 DOI: 10.3390/microorganisms7100455] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 12/15/2022] Open
Abstract
Tolerance to acid is of dual importance for the food-borne pathogen Listeria monocytogenes: acids are used as a preservative, and gastric acid is one of the first defenses within the host. There are considerable differences in the acid tolerance of strains. Here we present the transcriptomic response of acid-tolerant field strains of L. monocytogenes to HCl at pH 3.0. RNAseq revealed significant differential expression of genes involved in phosphotransferase systems, oxidative phosphorylation, cell morphology, motility, and biofilm formation. Genes in the acetoin biosynthesis pathway were upregulated, suggesting that L. monocytogenes shifts to metabolizing pyruvate to acetoin under organic acid stress. We also identified the formation of cell aggregates in microcolonies as a potential relief strategy. A motif search within the first 150 bp upstream of differentially expressed genes identified a novel potential regulatory sequence that may have a function in the regulation of virulence gene expression. Our data support a model where an excess of intracellular H+ ions is counteracted by pumping H+ out of the cytosol via cytochrome C under reduced activity of the ATP synthase. The observed morphological changes suggest that acid stress may cause cells to aggregate in biofilm microcolonies to create a more favorable microenvironment. Additionally, HCl stress in the host stomach may serve as (i) a signal to downregulate highly immunogenic flagella, and (ii) as an indicator for the imminent contact with host cells which triggers early stage virulence genes.
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Affiliation(s)
- Jule Anna Horlbog
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, 8006 Zürich, Switzerland.
| | - Marc J A Stevens
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, 8006 Zürich, Switzerland.
| | - Roger Stephan
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, 8006 Zürich, Switzerland.
| | - Claudia Guldimann
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, 8006 Zürich, Switzerland.
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Balasubramanian S, Subramanian R. Metabolic perturbation of acrylate pathway in Lactobacillus plantarum. BIOCATAL BIOTRANSFOR 2019. [DOI: 10.1080/10242422.2019.1606215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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15
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Williams-Rhaesa AM, Rubinstein GM, Scott IM, Lipscomb GL, Poole Ii FL, Kelly RM, Adams MWW. Engineering redox-balanced ethanol production in the cellulolytic and extremely thermophilic bacterium, Caldicellulosiruptor bescii. Metab Eng Commun 2018; 7:e00073. [PMID: 30009131 PMCID: PMC6041484 DOI: 10.1016/j.mec.2018.e00073] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 05/16/2018] [Accepted: 05/27/2018] [Indexed: 11/06/2022] Open
Abstract
Caldicellulosiruptor bescii is an extremely thermophilic cellulolytic bacterium with great potential for consolidated bioprocessing of renewable plant biomass. Since it does not natively produce ethanol, metabolic engineering is required to create strains with this capability. Previous efforts involved the heterologous expression of the gene encoding a bifunctional alcohol dehydrogenase, AdhE, which uses NADH as the electron donor to reduce acetyl-CoA to ethanol. Acetyl-CoA produced from sugar oxidation also generates reduced ferredoxin but there is no known pathway for the transfer of electrons from reduced ferredoxin to NAD in C. bescii. Herein, we engineered a strain of C. bescii using a more stable genetic background than previously reported and heterologously-expressed adhE from Clostridium thermocellum (which grows optimally (Topt) at 60 °C) with and without co-expression of the membrane-bound Rnf complex from Thermoanaerobacter sp. X514 (Topt 60 °C). Rnf is an energy-conserving, reduced ferredoxin NAD oxidoreductase encoded by six genes (rnfCDGEAB). It was produced in a catalytically active form in C. bescii that utilized the largest DNA construct to be expressed in this organism. The new genetic lineage containing AdhE resulted in increased ethanol production compared to previous reports. Ethanol production was further enhanced by the presence of Rnf, which also resulted in decreased production of pyruvate, acetoin and an uncharacterized compound as unwanted side-products. Using crystalline cellulose as the growth substrate for the Rnf-containing strain, 75 mM (3.5 g/L) ethanol was produced at 60 °C, which is 5-fold higher than that reported previously. This underlines the importance of redox balancing and paves the way for achieving even higher ethanol titers in C. bescii. New stable genetic background results in higher ethanol production. Ethanol production is enhanced further by reduced ferredoxin NAD oxidoreductase (Rnf). Rnf decreases pyruvate, acetoin and an unknown compound as unwanted side products. Maximum ethanol production is five-times higher than that achieved previously.
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Affiliation(s)
| | - Gabriel M Rubinstein
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Israel M Scott
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Gina L Lipscomb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Farris L Poole Ii
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Robert M Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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Lo R, Ho VTT, Bansal N, Turner MS. The genetic basis underlying variation in production of the flavour compound diacetyl by Lactobacillus rhamnosus strains in milk. Int J Food Microbiol 2018; 265:30-39. [DOI: 10.1016/j.ijfoodmicro.2017.10.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 08/01/2017] [Accepted: 10/28/2017] [Indexed: 01/16/2023]
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Huo Y, Zhan Y, Wang Q, Li S, Yang S, Nomura CT, Wang C, Chen S. Acetolactate synthase (AlsS) in Bacillus licheniformis WX-02: enzymatic properties and efficient functions for acetoin/butanediol and L-valine biosynthesis. Bioprocess Biosyst Eng 2017; 41:87-96. [PMID: 29026998 DOI: 10.1007/s00449-017-1847-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/23/2017] [Indexed: 11/25/2022]
Abstract
Acetolactate synthase catalyzes two molecules of pyruvates to form α-acetolactate, which is further converted to acetoin and 2,3-butanediol. In this study, by heterologous expression in Escherichia coli, the enzymatic properties of acetolactate synthase (AlsS) from Bacillus licheniformis WX-02 were characterized. Its K m and k cat for pyruvate were 3.96 mM and 514/s, respectively. It has the optimal activity at pH 6.5, 37 °C and was feedback inhibited by L-valine, L-leucine and L-isoleucine. Furthermore, the alsS-deficient strain could not produce acetoin, 2,3-butanediol, and L-valine, while the complementary strain was able to restore these capacities. The alsS overexpressing strain produced higher amounts of acetoin/2,3-butanediol (57.06 g/L) and L-valine (2.68 mM), which were 10.90 and 92.80% higher than those of the control strain, respectively. This is the first report regarding the in-depth understanding of AlsS enzymatic properties and its functions in B. licheniformis, and overexpression of AlsS can effectively improve acetoin/2,3-butanediol and L-valine production in B. licheniformis. We envision that this AlsS can also be applied in the improvement of acetoin/2,3-butanediol and L-valine production in other microbes.
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Affiliation(s)
- Yanli Huo
- School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, People's Republic of China
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Yangyang Zhan
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Qin Wang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Shunyi Li
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Shihui Yang
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Christopher T Nomura
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
- Department of Chemistry, The State University of New York College of Environmental Science and Forestry (SUNY ESF), Syracuse, NY, 13210, USA
| | - Changjun Wang
- Tobacco Research Institute of Hubei Province, Wuhan, 430062, People's Republic of China.
| | - Shouwen Chen
- Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China.
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
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Enhancement of Surfactin and Fengycin Production by Bacillus mojavensis A21: Application for Diesel Biodegradation. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5893123. [PMID: 29082251 PMCID: PMC5610860 DOI: 10.1155/2017/5893123] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/27/2017] [Accepted: 06/08/2017] [Indexed: 12/05/2022]
Abstract
This work concerns the study of the enhancement of surfactin and fengycin production by B. mojavensis A21 and application of the produced product in diesel biodegradation. The influences of the culture medium and cells immobilization were studied. The highest lipopeptides production was achieved after 72 hours of incubation in a culture medium containing 30 g/L glucose as carbon source and a combination of yeast extract (1 g/L) and glutamic acid (5 g/L) as nitrogen sources with initial pH 7.0 at 30°C and 90% volumetric aeration. The study of primary metabolites production showed mainly the production of acetoin, with a maximum production after 24 h of strain growth. The use of immobilized cells seemed to be a promising method for improving lipopeptides productivity. In fact, the synthesis of both lipopeptides, mainly fengycin, was greatly enhanced by the immobilization of A21 cells. An increase of diesel degradation capacity of approximately 20, 27, and 40% in the presence of 0.5, 1, and 2 g/L of produced lipopeptides, respectively, was observed. Considering these properties, B. mojavensis A21 strain producing a lipopeptide mixture, containing both surfactin and fengycin, may be considered as a potential candidate for future use in bioremediation and crop protection.
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Improvement of glycerol catabolism in Bacillus licheniformis for production of poly-γ-glutamic acid. Appl Microbiol Biotechnol 2017; 101:7155-7164. [PMID: 28804802 DOI: 10.1007/s00253-017-8459-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 07/08/2017] [Accepted: 07/30/2017] [Indexed: 01/08/2023]
Abstract
Bacillus licheniformis WX-02 is a well-studied strain to produce poly-γ-glutamic acid (γ-PGA) with numerous applications. This study is to improve WX-02 strain's capability of assimilating glycerol, a major byproduct of biofuels industries, through metabolic manipulation. Through gene knockout, the GlpK pathway was identified as the sole functional glycerol catabolism pathway, while the DhaK pathway was inactive for this strain under either aerobic or anaerobic conditions. The enhancement of glycerol utilization was attempted by substituting the native glpFK promoter with the constitutive promoter (P43), ytzE promoter (PytzE), and bacABC operon promoter (PbacA), respectively. The glycerol consumptions of the corresponding mutant strains WX02-P43glpFK, WX02-PytzEglpFK, and WX02-PbacAglpFK were 30.9, 26.42, and 18.8% higher than that of the WX-02 strain, respectively. The γ-PGA concentrations produced by the three mutant strains were 33.71, 23.39, and 30.05% higher than that of WX-02 strain, respectively. When biodiesel-derived crude glycerol was used as the carbon source, the mutant WX02-P43glpFK produced 16.63 g L-1 of γ-PGA, with a productivity of 0.35 g L-1 h-1. Collectively, this study demonstrated that glycerol can be used as an effective substrate for producing γ-PGA by metabolic engineering B. licheniformis strains.
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Tomita S, Saito K, Nakamura T, Sekiyama Y, Kikuchi J. Rapid discrimination of strain-dependent fermentation characteristics among Lactobacillus strains by NMR-based metabolomics of fermented vegetable juice. PLoS One 2017; 12:e0182229. [PMID: 28759594 PMCID: PMC5536307 DOI: 10.1371/journal.pone.0182229] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/16/2017] [Indexed: 11/19/2022] Open
Abstract
In this study, we investigated the applicability of NMR-based metabolomics to discriminate strain-dependent fermentation characteristics of lactic acid bacteria (LAB), which are important microorganisms for fermented food production. To evaluate the discrimination capability, six type strains of Lactobacillus species and six additional L. brevis strains were used focusing on i) the difference between homo- and hetero-lactic fermentative species and ii) strain-dependent characteristics within L. brevis. Based on the differences in the metabolite profiles of fermented vegetable juices, non-targeted principal component analysis (PCA) clearly separated the samples into those inoculated with homo- and hetero-lactic fermentative species. The separation was primarily explained by the different levels of dominant metabolites (lactic acid, acetic acid, ethanol, and mannitol). Orthogonal partial least squares discrimination analysis, based on a regions-of-interest (ROIs) approach, revealed the contribution of low-abundance metabolites: acetoin, phenyllactic acid, p-hydroxyphenyllactic acid, glycerophosphocholine, and succinic acid for homolactic fermentation; and ornithine, tyramine, and γ-aminobutyric acid (GABA) for heterolactic fermentation. Furthermore, ROIs-based PCA of seven L. brevis strains separated their strain-dependent fermentation characteristics primarily based on their ability to utilize sucrose and citric acid, and convert glutamic acid and tyrosine into GABA and tyramine, respectively. In conclusion, NMR metabolomics successfully discriminated the fermentation characteristics of the tested strains and provided further information on metabolites responsible for these characteristics, which may impact the taste, aroma, and functional properties of fermented foods.
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Affiliation(s)
- Satoru Tomita
- Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
- * E-mail:
| | - Katsuichi Saito
- Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Toshihide Nakamura
- Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
| | - Yasuyo Sekiyama
- Food Research Institute, National Agriculture and Food Research Organization (NARO), Tsukuba, Japan
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
| | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, Yokohama, Japan
- Graduate School of Medical Life Science, Yokohama City University, Yokohama, Japan
- Graduate School of Bioagricultural Sciences and School of Agricultural Sciences, Nagoya University, Nagoya, Japan
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Tian H, Shen Y, Yu H, He Y, Chen C. Effects of 4 Probiotic Strains in Coculture with Traditional Starters on the Flavor Profile of Yogurt. J Food Sci 2017; 82:1693-1701. [PMID: 28598540 DOI: 10.1111/1750-3841.13779] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/15/2017] [Accepted: 05/08/2017] [Indexed: 11/26/2022]
Abstract
To study the influence of probiotics on the flavor profile of yogurt, 4 probiotics, including Lactobacillus acidophilus, Lactobacillus plantarum, Lactobacillus rhamnosus, and Lactobacillus casei, were cofermented with traditional starters. The changes of bacterial growth, acid contents and volatile compounds of yogurt were investigated during fermentation and refrigerated storage. The strains that exhibited a low growth rate in milk did not significantly affect the bacterial population dynamics, acidity, or organic acid content during fermentation and storage. However, high viability and enhancement of postacidification were clearly observed in the samples that contained strains with a high growth rate in milk, particularly L. casei. A total of 45 volatile compounds, detected in most samples, were identified by headspace solid-phase micro-extraction followed by gas chromatography-mass spectrometry. Among these compounds, ketones and aldehydes were the most abundant. The presence of either L. rhamnosus or L. plantarum did not significantly affect the major volatile compounds, while contributions of L. casei and L. acidophilus were found in the formation of minor volatile metabolites. Electronic nose measurements exhibited a good discrimination of samples that contained different probiotics during refrigerated storage.
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Affiliation(s)
- Huaixiang Tian
- Shanghai Inst. of Technology, Dept. of Food Science and Technology, Shanghai, China
| | - Yongbo Shen
- Shanghai Inst. of Technology, Dept. of Food Science and Technology, Shanghai, China
| | - Haiyan Yu
- Shanghai Inst. of Technology, Dept. of Food Science and Technology, Shanghai, China
| | - Yujie He
- Shanghai Inst. of Technology, Dept. of Food Science and Technology, Shanghai, China
| | - Chen Chen
- Shanghai Inst. of Technology, Dept. of Food Science and Technology, Shanghai, China
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Sidira M, Santarmaki V, Kiourtzidis M, Argyri AA, Papadopoulou OS, Chorianopoulos N, Tassou C, Kaloutsas S, Galanis Α, Kourkoutas Y. Evaluation of immobilized Lactobacillus plantarum 2035 on whey protein as adjunct probiotic culture in yoghurt production. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2016.08.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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23
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Eram MS, Ma K. Pyruvate decarboxylase activity of the acetohydroxyacid synthase of Thermotoga maritima. Biochem Biophys Rep 2016; 7:394-399. [PMID: 28955930 PMCID: PMC5613635 DOI: 10.1016/j.bbrep.2016.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 06/20/2016] [Accepted: 07/13/2016] [Indexed: 11/30/2022] Open
Abstract
Acetohydroxyacid synthase (AHAS) catalyzes the production of acetolactate from pyruvate. The enzyme from the hyperthermophilic bacterium Thermotoga maritima has been purified and characterized (kcat ~100 s−1). It was found that the same enzyme also had the ability to catalyze the production of acetaldehyde and CO2 from pyruvate, an activity of pyruvate decarboxylase (PDC) at a rate approximately 10% of its AHAS activity. Compared to the catalytic subunit, reconstitution of the individually expressed and purified catalytic and regulatory subunits of the AHAS stimulated both activities of PDC and AHAS. Both activities had similar pH and temperature profiles with an optimal pH of 7.0 and temperature of 85 °C. The enzyme kinetic parameters were determined, however, it showed a non-Michaelis-Menten kinetics for pyruvate only. This is the first report on the PDC activity of an AHAS and the second bifunctional enzyme that might be involved in the production of ethanol from pyruvate in hyperthermophilic microorganisms. The acetohydroxyacid synthase of T. maritima has pyruvate decarboxylase activity The AHAS and PDC activities share the same temperature and pH optima Reconstitution of the catalytic and regulatory subunits increases both PDC and AHAS activities
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Affiliation(s)
- Mohammad S Eram
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Kesen Ma
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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Chaudhari SS, Thomas VC, Sadykov MR, Bose JL, Ahn DJ, Zimmerman MC, Bayles KW. The LysR-type transcriptional regulator, CidR, regulates stationary phase cell death in Staphylococcus aureus. Mol Microbiol 2016; 101:942-53. [PMID: 27253847 DOI: 10.1111/mmi.13433] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 11/29/2022]
Abstract
The Staphylococcus aureus LysR-type transcriptional regulator, CidR, activates the expression of two operons including cidABC and alsSD that display pro- and anti-death functions, respectively. Although several investigations have focused on the functions of different genes associated with these operons, the collective role of the CidR regulon in staphylococcal physiology is not clearly understood. Here we reveal that the primary role of this regulon is to limit acetate-dependent potentiation of cell death in staphylococcal populations. Although both CidB and CidC promote acetate generation and cell death, the CidR-dependent co-activation of CidA and AlsSD counters the effects of CidBC by redirecting intracellular carbon flux towards acetoin formation. From a mechanistic standpoint, we demonstrate that CidB is necessary for full activation of CidC, whereas CidA limits the abundance of CidC in the cell.
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Affiliation(s)
- Sujata S Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Vinai C Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Marat R Sadykov
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Jeffrey L Bose
- Department of Microbiology, Molecular Genetics and Immunology, The University of Kansas Medical Center, MSN 3029, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Daniel J Ahn
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA
| | - Matthew C Zimmerman
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kenneth W Bayles
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, 68198-5900, USA.
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Toya Y, Hirasawa T, Ishikawa S, Chumsakul O, Morimoto T, Liu S, Masuda K, Kageyama Y, Ozaki K, Ogasawara N, Shimizu H. Enhanced dipicolinic acid production during the stationary phase in Bacillus subtilis by blocking acetoin synthesis. Biosci Biotechnol Biochem 2015; 79:2073-80. [DOI: 10.1080/09168451.2015.1060843] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Abstract
Bacterial bio-production during the stationary phase is expected to lead to a high target yield because the cells do not consume the substrate for growth. Bacillus subtilis is widely used for bio-production, but little is known about the metabolism during the stationary phase. In this study, we focused on the dipicolinic acid (DPA) production by B. subtilis and investigated the metabolism. We found that DPA production competes with acetoin synthesis and that acetoin synthesis genes (alsSD) deletion increases DPA productivity by 1.4-fold. The mutant showed interesting features where the glucose uptake was inhibited, whereas the cell density increased by approximately 50%, resulting in similar volumetric glucose consumption to that of the parental strain. The metabolic profiles revealed accumulation of pyruvate, acetyl-CoA, and the TCA cycle intermediates in the alsSD mutant. Our results indicate that alsSD-deleted B. subtilis has potential as an effective host for stationary-phase production of compounds synthesized from these intermediates.
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Affiliation(s)
- Yoshihiro Toya
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Suita, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
| | - Takashi Hirasawa
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Suita, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Department of Bioengineering, Tokyo Institute of Technology, Yokohama, Japan
| | - Shu Ishikawa
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Graduate School of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Onuma Chumsakul
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Graduate School of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Takuya Morimoto
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Biological Science Laboratories, Kao Corporation, Haga, Japan
| | - Shenghao Liu
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Biological Science Laboratories, Kao Corporation, Haga, Japan
| | - Kenta Masuda
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Biological Science Laboratories, Kao Corporation, Haga, Japan
| | - Yasushi Kageyama
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Biological Science Laboratories, Kao Corporation, Haga, Japan
| | - Katsuya Ozaki
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Biological Science Laboratories, Kao Corporation, Haga, Japan
| | - Naotake Ogasawara
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
- Graduate School of Biological Science, Nara Institute of Science and Technology, Ikoma, Japan
| | - Hiroshi Shimizu
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Suita, Japan
- Advanced Low Carbon Technology Research and Development Program, Japan Science and Technology Agency (JST, ALCA), Japan
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Burmester A, Willumeit-Römer R, Feyerabend F. Behavior of bone cells in contact with magnesium implant material. J Biomed Mater Res B Appl Biomater 2015; 105:165-179. [PMID: 26448207 DOI: 10.1002/jbm.b.33542] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/03/2015] [Accepted: 09/17/2015] [Indexed: 01/10/2023]
Abstract
Magnesium-based implants exhibit several advantages, such as biodegradability and possible osteoinductive properties. Whether the degradation may induce cell type-specific changes in metabolism still remains unclear. To examine the osteoinductivity mechanisms, the reaction of bone-derived cells (MG63, U2OS, SaoS2, and primary human osteoblasts (OB)) to magnesium (Mg) was determined. Mg-based extracts were used to mimic more realistic Mg degradation conditions. Moreover, the influence of cells having direct contact with the degrading Mg metal was investigated. In exposure to extracts and in direct contact, the cells decreased pH and osmolality due to metabolic activity. Proliferating cells showed no significant reaction to extracts, whereas differentiating cells were negatively influenced. In contrast to extract exposure, where cell size increased, in direct contact to magnesium, cell size was stable or even decreased. The amount of focal adhesions decreased over time on all materials. Genes involved in bone formation were significantly upregulated, especially for primary human osteoblasts. Some osteoinductive indicators were observed for OB: (i) an increased cell count after extract addition indicated a higher proliferation potential; (ii) increased cell sizes after extract supplementation in combination with augmented adhesion behavior of these cells suggest an early switch to differentiation; and (iii) bone-inducing gene expression patterns were determined for all analyzed conditions. The results from the cell lines were inhomogeneous and showed no specific stimulus of Mg. The comparison of the different cell types showed that primary cells of the investigated tissue should be used as an in vitro model if Mg is analyzed. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 165-179, 2017.
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Affiliation(s)
- Anna Burmester
- Department for Material Design and Characterisation, Helmholtz-Zentrum Geesthacht, Institute of Material Research, 21502, Geesthacht, Germany
| | - Regine Willumeit-Römer
- Department for Material Design and Characterisation, Helmholtz-Zentrum Geesthacht, Institute of Material Research, 21502, Geesthacht, Germany
| | - Frank Feyerabend
- Department for Material Design and Characterisation, Helmholtz-Zentrum Geesthacht, Institute of Material Research, 21502, Geesthacht, Germany
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27
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Ianniello R, Zheng J, Zotta T, Ricciardi A, Gänzle M. Biochemical analysis of respiratory metabolism in the heterofermentativeLactobacillus spicheriandLactobacillus reuteri. J Appl Microbiol 2015; 119:763-75. [DOI: 10.1111/jam.12853] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 04/27/2015] [Accepted: 05/12/2015] [Indexed: 01/01/2023]
Affiliation(s)
- R.G. Ianniello
- Department of Agricultural, Food and Nutritional Science; University of Alberta; Edmonton AB Canada
- Scuola di Scienze Agrarie; Forestali, Alimentari e Ambientali; Università degli Studi della Basilicata; Potenza Italy
| | - J. Zheng
- State Key Laboratory of Agricultural Microbiology; Huazhong Agricultural University; Wuhan Hubei China
| | - T. Zotta
- Istituto di Scienze dell'Alimentazione-CNR; Avellino Italy
| | - A. Ricciardi
- Scuola di Scienze Agrarie; Forestali, Alimentari e Ambientali; Università degli Studi della Basilicata; Potenza Italy
| | - M.G. Gänzle
- Department of Agricultural, Food and Nutritional Science; University of Alberta; Edmonton AB Canada
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Lyu Z, Lu Y. Comparative genomics of three Methanocellales strains reveal novel taxonomic and metabolic features. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:526-537. [PMID: 25727385 DOI: 10.1111/1758-2229.12283] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/22/2015] [Indexed: 06/04/2023]
Abstract
Methanocellales represents a new order of methanogens, which is widespread in environments and plays specifically the important role in methane emissions from paddy fields. To gain more insights into Methanocellales, comparative genomic studies were performed among three Methanocellales strains through the same annotation pipeline. Genetic relationships among strains revealed by genome alignment, pan-genome reconstruction and comparison of amino average identity suggest that they should be classified in different genera. In addition, multiple copies of cell cycle regulator proteins were identified for the first time in Archaea. Core metabolisms were reconstructed, predicting certain unique and novel features for Methanocellales, including a set of methanogenesis genes potentially organized toward specialization in utilizing low concentrations of H2, a new route of disulfide reduction catalysed by a disulfide-reducing hydrogenase (Drh) complex phylogenetically related to sulfate-reducing prokaryotes, an oxidative tricarboxylic acid (TCA) cycle, a sophisticated nitrogen uptake and regulation system as well as a versatile sulfur utilization system. These core metabolisms are largely conserved among the three strains, but differences in gene copy number and metabolic diversity are evident. The present study thus adds new dimensions to the unique ecophysiology of Methanocellales and offers a road map for further experimental characterization of this methanogen lineage.
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Affiliation(s)
- Zhe Lyu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
| | - Yahai Lu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China
- College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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Zuljan FA, Repizo GD, Alarcon SH, Magni C. α-Acetolactate synthase of Lactococcus lactis contributes to pH homeostasis in acid stress conditions. Int J Food Microbiol 2014; 188:99-107. [DOI: 10.1016/j.ijfoodmicro.2014.07.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 06/03/2014] [Accepted: 07/16/2014] [Indexed: 10/25/2022]
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30
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Lee SC, Jung IP, Baig IA, Chien PN, La IJ, Yoon MY. Mutational analysis of critical residues of FAD-independent catabolic acetolactate synthase from Enterococcus faecalis V583. Int J Biol Macromol 2014; 72:104-9. [PMID: 25128823 DOI: 10.1016/j.ijbiomac.2014.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 08/02/2014] [Accepted: 08/04/2014] [Indexed: 10/24/2022]
Abstract
Catabolic acetolactate synthase (cALS) from Enterococcus faecalis is a FAD-independent enzyme, which catalyzes the condensation of two molecules of pyruvate to produce acetolactate. Mutational and kinetic analyses of variants suggested the importance of H111, Q112, and Q411 residues for catalysis in cALS. The wild-type and variants were expressed as equally soluble proteins and co-migrated to a size of 60 kDa on SDS-PAGE. Importantly, H111 in cALS, which is widely present as phenylalanine in many other ThDP-dependent enzymes, plays a crucial role in substrate binding. Interestingly, the H111 variants, H111R and H111F, demonstrated altered specific activity of H111 variants with 17- and 26-fold increases in Km, respectively, compared to wild-type cALS. Furthermore, Q112 variants, Q112E, Q112N, and Q112V, exhibited significantly lower specific activity with 70-, 15-, and 10-fold higher Ks for ThDP, respectively. In the case of Q411, the variant Q411E showed a 10-fold rise in Km and a 20-fold increase in Ks for ThDP. Further, the molecular docking results indicated that the binding mode of ThDP was slightly affected in the variants of cALS. Based on these results, we suggest that H111 plays a role in substrate binding, and further suggest that Q112 and Q411 might be involved in ThDP binding of cALS.
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Affiliation(s)
- Sang-Choon Lee
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
| | - In-Pil Jung
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
| | - Irshad Ahmed Baig
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
| | - Pham Ngoc Chien
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
| | - Im-Joung La
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea
| | - Moon-Young Yoon
- Department of Chemistry, College of Natural Science, Hanyang University, Seoul 133-791, Republic of Korea.
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31
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Thomas VC, Sadykov MR, Chaudhari SS, Jones J, Endres JL, Widhelm TJ, Ahn JS, Jawa RS, Zimmerman MC, Bayles KW. A central role for carbon-overflow pathways in the modulation of bacterial cell death. PLoS Pathog 2014; 10:e1004205. [PMID: 24945831 PMCID: PMC4063974 DOI: 10.1371/journal.ppat.1004205] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/08/2014] [Indexed: 12/17/2022] Open
Abstract
Similar to developmental programs in eukaryotes, the death of a subpopulation of cells is thought to benefit bacterial biofilm development. However mechanisms that mediate a tight control over cell death are not clearly understood at the population level. Here we reveal that CidR dependent pyruvate oxidase (CidC) and α-acetolactate synthase/decarboxylase (AlsSD) overflow metabolic pathways, which are active during staphylococcal biofilm development, modulate cell death to achieve optimal biofilm biomass. Whereas acetate derived from CidC activity potentiates cell death in cells by a mechanism dependent on intracellular acidification and respiratory inhibition, AlsSD activity effectively counters CidC action by diverting carbon flux towards neutral rather than acidic byproducts and consuming intracellular protons in the process. Furthermore, the physiological features that accompany metabolic activation of cell death bears remarkable similarities to hallmarks of eukaryotic programmed cell death, including the generation of reactive oxygen species and DNA damage. Finally, we demonstrate that the metabolic modulation of cell death not only affects biofilm development but also biofilm-dependent disease outcomes. Given the ubiquity of such carbon overflow pathways in diverse bacterial species, we propose that the metabolic control of cell death may be a fundamental feature of prokaryotic development. Many bacterial species including the pathogen Staphylococcus aureus are capable of adhering to surfaces and forming complex communities called biofilms. This mode of growth can be particularly challenging from an infection control standpoint, as they are often refractory to antibiotics and host immune system. Although developmental processes underlying biofilm formation are not entirely clear, recent evidence suggests that cell death of a subpopulation is crucial for its maturation. In this study we provide insight regarding the metabolic pathways that control cell death and demonstrate that acetate, a by-product of glucose catabolism, potentiates a form of cell death that exhibits physiological and biochemical hallmarks of apoptosis in eukaryotic organisms. Finally, we demonstrate that altering the ability of metabolic pathways that regulate acetate mediated cell death in S. aureus affects the outcome of biofilm-related diseases, such as infective endocarditis.
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Affiliation(s)
- Vinai Chittezham Thomas
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Marat R. Sadykov
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Sujata S. Chaudhari
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Joselyn Jones
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jennifer L. Endres
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Todd J. Widhelm
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Jong-Sam Ahn
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Randeep S. Jawa
- Department of Surgery, Stony Brook University School of Medicine, Stony Brook, New York, United States of America
| | - Matthew C. Zimmerman
- Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kenneth W. Bayles
- Center for Staphylococcal Research, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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Xu Y, Chu H, Gao C, Tao F, Zhou Z, Li K, Li L, Ma C, Xu P. Systematic metabolic engineering of Escherichia coli for high-yield production of fuel bio-chemical 2,3-butanediol. Metab Eng 2014; 23:22-33. [DOI: 10.1016/j.ymben.2014.02.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/15/2014] [Accepted: 02/03/2014] [Indexed: 12/25/2022]
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33
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2,3-Butanediol fermentation promotes growth of Serratia plymuthica at low pH but not survival of extreme acid challenge. Int J Food Microbiol 2014; 175:36-44. [DOI: 10.1016/j.ijfoodmicro.2014.01.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/23/2014] [Accepted: 01/26/2014] [Indexed: 01/10/2023]
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Fan Y, Tian Y, Zhao X, Zhang J, Liu J. Isolation of acetoin-producing Bacillus strains from Japanese traditional food-natto. Prep Biochem Biotechnol 2014; 43:551-64. [PMID: 23742087 DOI: 10.1080/10826068.2012.762631] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In this study, Bacillus strains with an ability to produce acetoin were isolated from a Japanese traditional food, natto, on the basis of the Voges-Proskauer (VP) reaction, and strain SF4-3 was shown to be a predominant strain in acetoin production. Based on a variety of morphological, physiological, and biochemical characteristics as well as the nucleotide sequence analysis of 16S rDNA, the strain SF4-3 was identified as Bacillus subtilis. When it was incubated at 37°C with a speed of 180 rpm for 96 hr in the flasks, the maximum acetoin concentration was up to 33.90 g/L. The fermentation broths were determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analyses; the results showed that the major metabolite was acetoin, and the purity could reach more than 95% without butanedione and 2,3-butanediol, which were usually produced together with acetoin in other strains. A novel aqueous two-phase system (ATPS) composed of hydrophilic solvents and inorganic salts was developed for the extraction of acetoin from fermentation broths. The ethanol and dipotassium hydrogen phosphate system could be used to extract acetoin from fermentation broths. The influences of phase composition on partition of acetoin were investigated. The maximum partition coefficient (9.68) and recovery (94.6%) of acetoin were obtained, when 25% (w/w) dipotassium hydrogen phosphate and 24% (w/w) ethanol were used.
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Affiliation(s)
- Yixiao Fan
- College of Food and Biological Engineering, Shandong Polytechnic University Changqing, Shandong, PR China
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35
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Metabolic engineering of Lactobacillus plantarum for succinic acid production through activation of the reductive branch of the tricarboxylic acid cycle. Enzyme Microb Technol 2013; 53:97-103. [DOI: 10.1016/j.enzmictec.2013.04.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 04/19/2013] [Accepted: 04/22/2013] [Indexed: 11/20/2022]
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36
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Abstract
The Gram-positive soil bacterium Bacillus subtilis encounters changing environmental conditions in its habitat. The access to oxygen determines the mode of energy generation. A complex regulatory network is employed to switch from oxygen respiration to nitrate respiration and various fermentative processes. During adaptation, oxygen depletion is sensed by the [4Fe-4S](2+) cluster containing Fnr and the two-component regulatory system ResDE consisting of the membrane-bound histidine kinase ResE and the cytoplasmic ResD regulator. Nitric oxide is the signal recognized by NsrR. Acetate formation and decreasing pH are measured via AlsR. Finally, Rex is responding to changes in the cellular NAD(+)/NADH ration. The fine-tuned interplay of these regulators at approximately 400 target gene promoters ensures efficient adaptation of the B. subtilis physiology.
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Affiliation(s)
- Elisabeth Härtig
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany.
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Zhang Y, Li S, Liu L, Wu J. Acetoin production enhanced by manipulating carbon flux in a newly isolated Bacillus amyloliquefaciens. BIORESOURCE TECHNOLOGY 2013; 130:256-60. [PMID: 23306133 DOI: 10.1016/j.biortech.2012.10.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/09/2012] [Accepted: 10/10/2012] [Indexed: 05/12/2023]
Abstract
A new strain, FMME044, exhibited a remarkable ability to synthesize acetoin and was identified as Bacillus amyloliquefaciens. The following characteristics of enzyme activity were found: 2,3-butanediol was reverse transformed to acetoin upon depletion of glucose; lower agitation speeds favored 2,3-butanediol accumulation; and higher agitation speeds favored reverse transformation of 2,3-butanediol to acetoin. In order to enhance acetoin production by manipulating the carbon flux distribution, a two-stage agitation speed control strategy was proposed: during the first 24h, the agitation speed was set to 350rpm to achieve a high 2,3-butanediol concentration and then the speed was increased to 500rpm to reverse transform 2,3-butanediol to acetoin. Following this strategy, a high titer (51.2gL(-1)), yield (0.43gg(-1)), and productivity (1.42gL(-1)h(-1)) of acetoin were achieved. The results demonstrated that B. amyloliquefaciens FMME044 is a potential industrial strain for acetoin production.
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Affiliation(s)
- Yanjie Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, Jiangsu Province, China
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38
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Characterization of recombinant FAD-independent catabolic acetolactate synthase from Enterococcus faecalis V583. Enzyme Microb Technol 2012. [PMID: 23199739 DOI: 10.1016/j.enzmictec.2012.10.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The catabolic acetolactate synthase (cALS) of Enterococcus faecalis V583 was cloned, expressed in Escherichia coli, and purified to homogeneity. The purified protein had a molecular weight of 60 kDa. The cALS of E. faecalis is highly homologous with other cALSs, while sharing low homology with its anabolic counterparts. The cALS of E. faecalis exhibits optimum activity at a temperature of 37°C and pH 6.8. Based on the enzyme characterization, the apparent K(m) for pyruvate was calculated to be 1.37 mM, while the K(c) for thiamin diphosphate (ThDP) and Mg(2+) were found to be 0.031 μM and 1.27 mM, respectively. Negligible absorbance at 450 nm and lack of activity enhancement upon addition of flavin adenine dinucleotide (FAD) to the assay buffer suggest that the cALS of E. faecalis is not FAD-dependent. The enzyme showed extreme stability against the organic solvent dimethyl sulfoxide (DMSO), whereas the activity decreased to less than 50% in the presence of acetone and ethanol.
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Growth, organic acids profile and sugar metabolism of Bifidobacterium lactis in co-culture with Streptococcus thermophilus: The inulin effect. Food Res Int 2012. [DOI: 10.1016/j.foodres.2012.02.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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40
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Chen D, Xu D, Li M, He J, Gong Y, Wu D, Sun M, Yu Z. Proteomic analysis of Bacillus thuringiensis ΔphaC mutant BMB171/PHB(-1) reveals that the PHB synthetic pathway warrants normal carbon metabolism. J Proteomics 2012; 75:5176-88. [PMID: 22705120 DOI: 10.1016/j.jprot.2012.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 05/28/2012] [Accepted: 06/03/2012] [Indexed: 10/28/2022]
Abstract
A phaC knockout mutant from Bacillus thuringiensis (Bt) strain BMB171, named BMB171/PHB(-1), was constructed. A physiological and metabolic investigation and a proteomic analysis were conducted for both ΔphaC mutant and its parent strain. Grown in peptone medium with 5 gram glucose per liter as sole carbon source, BMB171/PHB(-1) produced various organic acids. Here the excreted pyruvate, citrate, lactate, acetate and glutamate were quantitatively analyzed. Deletion of phaC gene from the BMB171 strain resulted in 1) growth delay; 2) higher consumption of dioxigen but lower cell yield; 3) stagnation of pH movement; 4) overproduction of organic acids; 5) rapid descent of cell density in the stationary phase; and 6) a sporulation-deficient phenotype. Our proteomic study with qPCR reconfirmation reveals that the absence of PhaC led to a metabolic turmoil which showed repressed glycolysis, and over-expressed TCA cycle, various futile pathways and amino acid synthesis during vegetative growth. It is thus thought that B. thuringiensis BMB171 effectively regulated its carbon metabolism upon the presence of the functional PHB synthetic pathway. The presence of this pathway warrants a PHB-producing bacterium better surviving under different environmental conditions.
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Affiliation(s)
- Deju Chen
- State Key Laboratory of Agricultural Microbiology and National Engineering Research Center for Microbial Pesticides, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei Province, PR China
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41
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Biswas R, Yamaoka M, Nakayama H, Kondo T, Yoshida KI, Bisaria VS, Kondo A. Enhanced production of 2,3-butanediol by engineered Bacillus subtilis. Appl Microbiol Biotechnol 2012; 94:651-8. [DOI: 10.1007/s00253-011-3774-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2011] [Revised: 11/08/2011] [Accepted: 11/20/2011] [Indexed: 11/29/2022]
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The transcription factor AlsR binds and regulates the promoter of the alsSD operon responsible for acetoin formation in Bacillus subtilis. J Bacteriol 2011; 194:1100-12. [PMID: 22178965 DOI: 10.1128/jb.06425-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis forms acetoin under anaerobic fermentative growth conditions and as a product of the aerobic carbon overflow metabolism. Acetoin formation from pyruvate requires α-acetolactate synthase and acetolactate decarboxylase, both encoded by the alsSD operon. The alsR gene, encoding the LysR-type transcriptional regulator AlsR, was found to be essential for the in vivo expression of alsSD in response to anaerobic acetate accumulation, the addition of acetate, low pH, and the aerobic stationary phase. The expressions of the alsSD operon and the alsR regulatory gene were independent of other regulators of the anaerobic regulatory network, including ResDE, Fnr, and ArfM. A negative autoregulation of alsR was observed. In vitro transcription from the alsSD promoter using purified B. subtilis RNA polymerase required AlsR. DNA binding studies with purified recombinant AlsR in combination with promoter mutagenesis experiments identified a 19-bp high-affinity palindromic binding site (TAAT-N(11)-ATTA) at positions -76 to -58 (regulatory binding site [RBS]) and a low-affinity site (AT-N(11)-AT) at positions -41 to -27 (activator binding site [ABS]) upstream of the transcriptional start site of alsSD. The RBS and ABS were found to be essential for in vivo alsSD transcription. AlsR binding to both sites induced the formation of higher-order, transcription-competent complexes. The AlsR protein carrying the S100A substitution at the potential coinducer binding site still bound to the RBS and ABS. However, AlsR(S100A) failed to form the higher-order complex and to initiate in vivo and in vitro transcription. A model for AlsR promoter binding and transcriptional activation was deduced.
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Madeo M, O'Riordan N, Fuchs TM, Utratna M, Karatzas KAG, O'Byrne CP. Thiamine plays a critical role in the acid tolerance of Listeria monocytogenes. FEMS Microbiol Lett 2011; 326:137-43. [PMID: 22092299 DOI: 10.1111/j.1574-6968.2011.02442.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 10/10/2011] [Accepted: 10/17/2011] [Indexed: 11/27/2022] Open
Abstract
Understanding the molecular basis of acid tolerance in the food-borne pathogen Listeria monocytogenes is important as this property contributes to survival in the food-chain and enhances survival within infected hosts. The aim of this study was to identify genes contributing to acid tolerance in L. monocytogenes using transposon mutagenesis and subsequently to elucidate the physiological role of these genes in acid tolerance. One mutant harboring a Tn917 insertion in the thiT gene (formerly lmo1429), which encodes a thiamine (vitamin B1) uptake system, was found to be highly sensitive to acid. The acid-sensitive phenotype associated with loss of this gene was confirmed with an independently isolated mutant, from which the thiT gene was deleted (∆thiT). Cells of both wild-type and ∆thiT mutant that were thiamine depleted were found to be significantly more acid sensitive than control cultures. Thiamine-depleted cultures failed to produce significant concentrations of acetoin, consistent with the known thiamine dependence of acetolactate synthase, an enzyme required for acetoin synthesis from pyruvate. As acetoin synthesis is a proton-consuming process, we suggest that the acid sensitivity observed in thiamine-depleted cultures may be owing to an inability to produce acetoin.
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Affiliation(s)
- Moira Madeo
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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44
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Repizo GD, Mortera P, Magni C. Disruption of the alsSD operon of Enterococcus faecalis impairs growth on pyruvate at low pH. Microbiology (Reading) 2011; 157:2708-2719. [DOI: 10.1099/mic.0.047662-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Diacetyl and acetoin are pyruvate-derived metabolites excreted by many micro-organisms, and are important in their physiology. Although generation of these four-carbon (C4) compounds in Enterococcus faecalis is a well-documented phenotype, little is known about the gene regulation of their biosynthetic pathway and the physiological role of the pathway in this bacterium. In this work, we identified the genes involved in C4 compound biosynthesis in Ent. faecalis and report their transcriptional analysis. These genes are part of the alsSD bicistronic operon, which encodes α-acetolactate synthase (AlsS) and α-acetolactate decarboxylase (AlsD). Our studies showed that alsSD operon transcription levels are maximal during the exponential phase of growth, decreasing thereafter. Furthermore, we found that this transcription is enhanced upon addition of pyruvate to the growth medium. In order to study the functional role of the alsSD operon, an isogenic alsSD mutant strain was constructed. This strain lost its capacity to generate C4 compounds, confirming the role of alsSD genes in this metabolic pathway. In contrast to the wild-type strain, the alsSD-deficient strain was unable to grow in LB medium supplemented with pyruvate at an initial pH of 4.5. This dramatic reduction in growth parameters for the mutant strain was simultaneously accompanied by the inability to alkalinize the internal and external medium under these conditions. In sum, these results suggest that the decarboxylation reactions related to the C4 biosynthetic pathway give enterococcal cells a competitive advantage during pyruvate metabolism at low pH.
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Affiliation(s)
- Guillermo D. Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina
| | - Pablo Mortera
- Instituto de Química Orgánica de Rosario (IQUIR-CONICET) and Departamento de Química Analítica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina
| | - Christian Magni
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina
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The effect of temperature and pH gradients on Lactobacillus rhamnosus gene expression of stress-related genes. Bioprocess Biosyst Eng 2011; 34:1169-76. [DOI: 10.1007/s00449-011-0568-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 06/30/2011] [Indexed: 11/25/2022]
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Abstract
Coping with acid environments is one of the prerequisites for the soil saprophytic and human pathogenic lifestyle of Bacillus cereus. This minireview highlights novel insights in the responses displayed by vegetative cells and germinating spores of B. cereus upon exposure to low pH as well as organic acids, including acetic acid, lactic acid and sorbic acid. Insights regarding the possible acid-inflicted damage, physiological responses and protective mechanisms have been compiled based on single cell fluorescence microscopy, flow cytometry and transcriptome analyses.
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Affiliation(s)
- Maarten Mols
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands.
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Increased fitness and alteration of metabolic pathways during Bacillus subtilis evolution in the laboratory. Appl Environ Microbiol 2011; 77:4105-18. [PMID: 21531833 DOI: 10.1128/aem.00374-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Five batch cultures of Bacillus subtilis were subjected to evolution in the laboratory for 6,000 generations under conditions repressing sporulation in complex liquid medium containing glucose. Between generations 1,000 and 2,000, variants with a distinct small-colony morphology arose and swept through four of the five populations that had been previously noted for their loss of sporulation (H. Maughan et al., Genetics 177:937-948, 2007). To better understand the nature of adaptation in these variants, individual strains were isolated from one population before (WN715) and after (WN716) the sweep. In addition to colony morphology, strains WN715 and WN716 differed in their motility, aerotaxis, and cell morphology. Competition experiments showed that strain WN716 had evolved a distinct fitness advantage over the ancestral strain and strain WN715 during growth and the transition to the postexponential growth phase, which was more pronounced when WN715 was present in the coculture. Microarray analyses revealed candidate genes in which mutations may have produced some of the observed phenotypes. For example, loss of motility in WN716 was accompanied by decreased transcription of all flagellar, motility, and chemotaxis genes on the microarray. Transcription of alsS and alsD was also lower in strain WN716, and the predicted loss of acetoin production and enhanced acetate production was confirmed by high-performance liquid chromatography (HPLC) analysis. The results suggested that the derived colony morphology of strain WN716 was associated with increased fitness, the alteration of several metabolic pathways, and the loss of a typical postexponential-phase response.
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Zalán Z, Hudáček J, Tóth-Markus M, Husová E, Solichová K, Hegyi F, Plocková M, Chumchalová J, Halász A. Sensorically and antimicrobially active metabolite production of Lactobacillus strains on Jerusalem artichoke juice. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2011; 91:672-679. [PMID: 21213229 DOI: 10.1002/jsfa.4232] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 10/21/2010] [Accepted: 10/23/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND In the tubers of Jerusalem artichoke (Helianthus tuberosus L.) the main carbohydrate is the well-known prebiotic inulin, which is a good growth substrate for gut microorganisms. Jerusalem artichoke tuber is traditionally consumed boiled or pickled rather than in fermented form. Lactic acid bacteria are traditionally used in the production of fermented foods; nevertheless their behavior and metabolite production are considerably influenced by the substrate. The purpose of this study was to investigate the growth and production of the most important sensorically and antimicrobially active metabolites of different Lactobacillus strains on Jerusalem artichoke juice. RESULTS All investigated strains grew well (in the range 10(9) cfu mL(-1) ) in the media. The organic acids (lactic acid, 110-337 mmol L(-1) ; acetic acid, 0-180 mmol L(-1) ; and succinic acid, 0-79 mmol L(-1) ), hydrogen peroxide (0.25-1.77 mg L(-1) ), mannitol (0.06-3.24 g L(-1) ), acetoin and diacetyl production of strains varies not only according to the species but also from strain to strain, which will be demonstrated and discussed in the paper. CONCLUSION Our results showed that lactobacilli can be used for the fermentation of Jerusalem artichoke, which in this form could be used, alone or mixed with other raw food material, as a new synbiotic functional food.
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Affiliation(s)
- Zsolt Zalán
- Central Food Research Institute, Unit of Biology, Herman Ottó u. 15., H-1022, Budapest, Hungary.
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Servili M, Rizzello CG, Taticchi A, Esposto S, Urbani S, Mazzacane F, Di Maio I, Selvaggini R, Gobbetti M, Di Cagno R. Functional milk beverage fortified with phenolic compounds extracted from olive vegetation water, and fermented with functional lactic acid bacteria. Int J Food Microbiol 2011; 147:45-52. [PMID: 21458095 DOI: 10.1016/j.ijfoodmicro.2011.03.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 02/15/2011] [Accepted: 03/03/2011] [Indexed: 11/26/2022]
Abstract
Functional milk beverages (FMB100 and FMB200) fortified with phenolic compounds (100 and 200mg/l) extracted from olive vegetable water, and fermented with γ-amino butyric acid (GABA)-producing (Lactobacillus plantarum C48) and autochthonous human gastro-intestinal (Lactobacillus paracasei 15N) lactic acid bacteria were manufactured. A milk beverage (MB), without addition of phenolic compounds, was used as the control. Except for a longer latency phase of FMB200, the three beverages showed an almost similar kinetic of acidification, consumption of lactose and synthesis of lactic acid. Apart from the beverage, Lb. plantarum C48 showed a decrease of ca. Log 2.52-2.24 cfu/ml during storage. The cell density of functional Lb. paracasei 15N remained always above the value of Log 8.0 cfu/ml. During fermentation, the total concentration of free amino acids markedly increased without significant (P > 0.05) differences between beverages. The concentration of GABA increased during fermentation and further storage (63.0 ± 0.6-67.0 ± 2.1mg/l) without significant (P > 0.05) differences between beverages. After fermentation, FMB100 and FMB200 showed the same phenolic composition of the phenol extract from olive vegetable water but a different ratio between 3,4-DHPEA and 3,4-DHPEA-EDA. During storage, the concentrations of 3,4-DHPEA-EDA, p-HPEA and verbascoside of both FMB100 and FMB200 decreased. Only the concentration of 3,4-DHPEA increased. As shown by SPME-GC-MS analysis, diactetyl, acetoin and, especially, acetaldehyde were the main volatile compounds found. The concentration of phenolic compounds does not interfere with the volatile composition. Sensory analyses based on triangle and paired comparison tests showed that phenolic compounds at the concentrations of 100 or 200mg/l were suitable for addition to functional milk beverages.
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Affiliation(s)
- M Servili
- Dipartimento di Scienze Economico-Estimative e degli Alimenti, Sezione di Tecnologie e Biotecnologie degli Alimenti, University of Perugia, 06126 Perugia, Italy
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50
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Ji XJ, Huang H, Ouyang PK. Microbial 2,3-butanediol production: a state-of-the-art review. Biotechnol Adv 2011; 29:351-64. [PMID: 21272631 DOI: 10.1016/j.biotechadv.2011.01.007] [Citation(s) in RCA: 430] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 01/07/2011] [Accepted: 01/19/2011] [Indexed: 12/01/2022]
Abstract
2,3-butanediol is a promising bulk chemical due to its extensive industry applications. The state-of-the-art nature of microbial 2,3-butanediol production is reviewed in this paper. Various strategies for efficient and economical microbial 2,3-butanediol production, including strain improvement, substrate alternation, and process development, are reviewed and compared with regard to their pros and cons. This review also summarizes value added derivatives of biologically produced 2,3-butanediol and different strategies for downstream processing. The future prospects of microbial 2,3-butanediol production are discussed in light of the current progress, challenges, and trends in this field. Guidelines for future studies are also proposed.
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Affiliation(s)
- Xiao-Jun Ji
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, No. 5 Xinmofan Road, Nanjing 210009, People's Republic of China
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