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Zhao S, Solem C. Thiamine-Starved Lactococcus lactis for Producing Food-Grade Pyruvate. J Agric Food Chem 2024; 72:4858-4868. [PMID: 38377583 DOI: 10.1021/acs.jafc.3c09216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Lactococcus lactis is a safe lactic acid bacterium widely used in dairy fermentations. Normally, its main fermentation product is lactic acid; however, L. lactis can be persuaded into producing other compounds, e.g., through genetic engineering. Here, we have explored the possibility of rewiring the metabolism of L. lactis into producing pyruvate without using genetic tools. Depriving the thiamine-auxotrophic and lactate dehydrogenase-deficient L. lactis strain RD1M5 of thiamine efficiently shut down two enzymes at the pyruvate branch, the thiamine pyrophosphate (TPP) dependent pyruvate dehydrogenase (PDHc) and α-acetolactate synthase (ALS). After eliminating the remaining enzyme acting on pyruvate, the highly oxygen-sensitive pyruvate formate lyase (PFL), by simple aeration, the outcome was pyruvate production. Pyruvate could be generated by nongrowing cells and cells growing in a substrate low in thiamine, e.g., Florisil-treated milk. Pyruvate is a precursor for the butter aroma compound diacetyl. Using an α-acetolactate decarboxylase deficient L. lactis strain, pyruvate could be converted to α-acetolactate and diacetyl. Summing up, by starving L. lactis for thiamine, secretion of pyruvate could be attained. The food-grade pyruvate produced has many applications, e.g., as an antioxidant or be used to make butter aroma.
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Affiliation(s)
- Shuangqing Zhao
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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2
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Eicher C, Coulon J, Favier M, Alexandre H, Reguant C, Grandvalet C. Citrate metabolism in lactic acid bacteria: is there a beneficial effect for Oenococcus oeni in wine? Front Microbiol 2024; 14:1283220. [PMID: 38249489 PMCID: PMC10798043 DOI: 10.3389/fmicb.2023.1283220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 12/08/2023] [Indexed: 01/23/2024] Open
Abstract
Lactic acid bacteria (LAB) are Gram positive bacteria frequently used in the food industry for fermentation, mainly transformation of carbohydrates into lactic acid. In addition, these bacteria also have the capacity to metabolize citrate, an organic acid commonly found in food products. Its fermentation leads to the production of 4-carbon compounds such as diacetyl, resulting in a buttery flavor desired in dairy products. Citrate metabolism is known to have several beneficial effects on LAB physiology. Nevertheless, a controversial effect of citrate has been described on the acid tolerance of the wine bacterium Oenococcus oeni. This observation raises questions about the effect of citrate on the capacity of O. oeni to conduct malolactic fermentation in highly acidic wines. This review aims to summarize the current understanding of citrate metabolism in LAB, with a focus on the wine bacterium O. oeni. Metabolism with the related enzymes is detailed, as are the involved genes organized in cit loci. The known systems of cit locus expression regulation are also described. Finally, the beneficial effects of citrate catabolism on LAB physiology are reported and the negative impact observed in O. oeni is discussed.
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Affiliation(s)
- Camille Eicher
- UMR PAM, Université de Bourgogne Franche-Comté, Institut Agro, Université de Bourgogne, INRAE, Dijon, France
| | | | | | - Hervé Alexandre
- UMR PAM, Université de Bourgogne Franche-Comté, Institut Agro, Université de Bourgogne, INRAE, Dijon, France
| | - Cristina Reguant
- Universitat Rovira i Virgili, Grup de Biotecnologia Enològica, Departament de Bioquímica i Biotecnologia, Tarragona, Catalonia, Spain
| | - Cosette Grandvalet
- UMR PAM, Université de Bourgogne Franche-Comté, Institut Agro, Université de Bourgogne, INRAE, Dijon, France
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3
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Gu L, Tadesse BT, Zhao S, Holck J, Zhao G, Solem C. Fermented butter aroma for plant-based applications. FEMS Microbiol Lett 2022; 369:6795930. [PMID: 36331038 DOI: 10.1093/femsle/fnac105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/30/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
Plant-based dairy alternatives are gaining increasing interest, e.g. alternatives to yoghurt, cheese, and butter. In all these products butter flavor (diacetyl + acetoin) plays an important role. We previously have reported efficient butter flavor formation from low value dairy side streams using a dairy isolate of Lactococcus lactis deficient in lactate dehydrogenase. Here, we have tested the ability of this strain, RD1M5, to form butter flavor in plant milks based on oat and soy. We found that oat milk, with its high sugar content, supported more efficient production of butter aroma, when compared to soy milk. When supplemented with glucose, efficient butter aroma production was achieved in soy milk as well. We also carried out an extended adaptive laboratory evolution of the dairy strain in oat milk. After two months of adaptation, we obtained a strain with enhanced capacity for producing butter aroma. Despite of its high sugar content, RD1M5 and its adapted version only metabolized approximately 10% of the fermentable sugars available in the oat milk, which we found was due to amino acid starvation and partly starvation for vitamins. The study demonstrates that dairy cultures have great potential for use in plant-based fermentations.
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Affiliation(s)
- Liuyan Gu
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Belay Tilahun Tadesse
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Shuangqing Zhao
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Jesper Holck
- Protein Chemistry and Enzyme Technology Section, DTU Bioengineering, Department of Biotechnology and Biomedicine, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Ge Zhao
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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Liu JM, Chen L, Jensen PR, Solem C. Food grade microbial synthesis of the butter aroma compound butanedione using engineered and non-engineered Lactococcus lactis. Metab Eng 2021; 67:443-452. [PMID: 34438072 DOI: 10.1016/j.ymben.2021.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/12/2021] [Accepted: 08/22/2021] [Indexed: 11/26/2022]
Abstract
The design-build-test-learn (DBTL) cycle has been implemented in metabolic engineering processes for optimizing the production of valuable compounds, including food ingredients. However, the use of recombinant microorganisms for producing food ingredients is associated with different challenges, e.g., in the EU, a content of more than 0.9% of such ingredients requires to be labeled. Therefore, we propose to expand the DBTL cycle and use the "learn" module to guide the development of non-engineered strains for clean label production. Here, we demonstrate how this approach can be used to generate engineered and natural cell factories able to produce the valuable food flavor compound - butanedione (diacetyl). Through comprehensive rerouting of the metabolism of Lactococcus lactis MG1363 and re-installment of the capacity to metabolize lactose and dairy protein, we managed to achieve a high titer of diacetyl (6.7 g/L) in pure dairy waste. Based on learnings from the engineering efforts, we successfully achieved the production of diacetyl without using recombinant DNA technology. We accomplish the latter by process optimization and by relying on high-throughput screening using a microfluidic system. Our results demonstrate the great potential that lies in combining metabolic engineering and natural approaches for achieving efficient production of food ingredients.
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Affiliation(s)
- Jian-Ming Liu
- The National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
| | - Lin Chen
- The National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
| | - Peter Ruhdal Jensen
- The National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
| | - Christian Solem
- The National Food Institute, Technical University of Denmark, Kongens Lyngby, 2800, Denmark.
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5
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Dorau R, Liu J, Solem C, Jensen PR. Metabolic Engineering of Lactic Acid Bacteria. Metab Eng 2021. [DOI: 10.1002/9783527823468.ch15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kim Y, Yoon S, Shin H, Jo M, Lee S, Kim SH. Isolation of Lactococcus lactis ssp. cremoris LRCC5306 and Optimization of Diacetyl Production Conditions for Manufacturing Sour Cream. Food Sci Anim Resour 2021; 41:373-385. [PMID: 34017948 PMCID: PMC8112315 DOI: 10.5851/kosfa.2021.e3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/26/2020] [Accepted: 01/23/2021] [Indexed: 11/06/2022] Open
Abstract
The sensory properties and flavor of sour cream are important factors that influence consumer acceptability. The present study aimed to isolate lactic acid bacteria with excellent diacetyl production ability and to optimize the fermentation conditions for sour cream manufacture. Lactococcus lactis ssp. cremoris was isolated as a lactic acid bacterium derived from raw milk. This strain showed the greatest diacetyl production among other strains and was named LRCC5306. Various culture conditions were optimized to improve the diacetyl production of LRCC5306. The highest diacetyl production was found to be at 105.04±2.06 mg/L, when 0.2% citric acid and 0.001% Fe2+ were added and cultured at 20°C for 15 h. Based on the optimal cultivation conditions, sour cream was manufactured using LRCC5306, with a viable count of 1.04×108 CFU/g and a diacetyl concentration of 106.56±1.53 mg/g. The electronic tongue system was used to compare the sensory properties of the sour cream; the fermented product exhibited sweetness and saltiness which was similar to that of an imported commercial product, but with slightly reduced bitterness and a significantly greater degree of sour taste. Therefore, our study shows that if cream is fermented using the LRCC5306, it is possible to produce sour cream with greatly improved sensory attractiveness, resulting in increased acceptance by consumers. Since this sour cream has a higher viable count of lactic acid bacteria, it is also anticipated that it will have a better probiotic effect.
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Affiliation(s)
- Yunsik Kim
- Department of Biosystems and
Biotechnology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
| | - Seokmin Yoon
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Hyejung Shin
- Department of Food Bioscience and
Technology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
| | - Miyoun Jo
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Sunmin Lee
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Sae-hun Kim
- Department of Food Bioscience and
Technology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
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Hernandez-Valdes JA, Solopova A, Kuipers OP. Development of Lactococcus lactis Biosensors for Detection of Diacetyl. Front Microbiol 2020; 11:1032. [PMID: 32523575 PMCID: PMC7261850 DOI: 10.3389/fmicb.2020.01032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Some secondary metabolites of fermentative bacteria are desired compounds for the food industry. Examples of these compounds are diacetyl and acetaldehyde, which are produced by species of the lactic acid bacteria (LAB) family. Diacetyl is an aromatic compound, giving the buttery flavor associated with dairy products, and acetaldehyde is the compound responsible for the yogurt flavor and aroma. The quantification of these compounds in food matrices is a laborious task that involves sample preparation and specific analytical methods. The ability of bacteria to naturally sense metabolites has successfully been exploited to develop biosensors that facilitate the identification and quantification of certain metabolites (Mahr and Frunzke, 2016). The presence of a specific metabolite is sensed by the biosensors, and it is subsequently translated into the expression of one or more reporter genes. In this study we aimed to develop fluorescence-based biosensors to detect diacetyl and acetaldehyde. Since the metabolic pathways for production and degradation of these compounds are present in Lactococcus lactis, the sensing mechanisms in this bacterium are expected. Thus, we identified diacetyl and acetaldehyde responsive promoters by performing transcriptome analyses in L. lactis. The characterization of the biosensors showed their response to the presence of these compounds, and a further analysis of the diacetyl-biosensors (its dynamics and orthogonality) was performed. Moreover, we attempted to produce natural diacetyl from producer strains, namely L. lactis subsp. lactis biovar diacetylactis, to benchmark the performance of our biosensors. The diacetyl-biosensors responded linearly to the amounts of diacetyl obtained in the bacterial supernatants, i.e., the increases in GFP expression were proportional to the amounts of diacetyl present in the supernatants of L. lactis subsp. lactis biovar diacetylactis MR3-T7 strain. The biosensors developed in this study may eventually be used to engineer strains or pathways for increased diacetyl and acetaldehyde production, and may facilitate the detection of these metabolites in complex food matrices.
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Affiliation(s)
- Jhonatan A Hernandez-Valdes
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
| | - Ana Solopova
- School of Microbiology, APC Microbiome, University College Cork, Cork, Ireland
| | - Oscar P Kuipers
- Department of Molecular Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands
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Liu JM, Chen L, Dorau R, Lillevang SK, Jensen PR, Solem C. From Waste to Taste-Efficient Production of the Butter Aroma Compound Acetoin from Low-Value Dairy Side Streams Using a Natural (Nonengineered) Lactococcus lactis Dairy Isolate. J Agric Food Chem 2020; 68:5891-5899. [PMID: 32363876 DOI: 10.1021/acs.jafc.0c00882] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Lactococcus lactis subsp. lactis biovar diacetylactis is widely used in dairy fermentations as it can form the butter aroma compounds acetoin and diacetyl from citrate in milk. Here, we explore the possibility of producing acetoin from the more abundant lactose. Starting from a dairy isolate of L. lactis biovar diacetylactis, we obtained a series of mutants with low lactate dehydrogenase (ldh) activity. One isolate, RD1M5, only had a single insertion mutation in the ldh gene compared to its parental strain as revealed by whole genome resequencing. We tested the ability of RD1M5 to produce acetoin in milk. With aeration, all the lactose could be consumed, and the only product was acetoin. In a simulated cheese fermentation, a 50% increase in acetoin concentration could be achieved. RD1M5 turned out to be an excellent cell factory for acetoin and was able to convert lactose in dairy waste into acetoin with high titer (41 g/L) and high yield (above 90% of the theoretical yield). Summing up, RD1M5 was found to be highly robust and to grow excellently in milk or dairy waste. Being natural in origin opens up for applications within dairies as well as for safe production of food-grade acetoin from low-cost substrates.
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Affiliation(s)
- Jian-Ming Liu
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Lin Chen
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Robin Dorau
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | | | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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9
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Tian H, Yu B, Ai L, Yu H, Chen C. A high-throughput system for screening high diacetyl-producing lactic acid bacteria in fermented milk in 96-well microplates. Food Measure 2020; 14:548-56. [DOI: 10.1007/s11694-019-00321-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10
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Dorau R, Chen L, Liu J, Jensen PR, Solem C. Efficient production of α-acetolactate by whole cell catalytic transformation of fermentation-derived pyruvate. Microb Cell Fact 2019; 18:217. [PMID: 31884954 PMCID: PMC6936138 DOI: 10.1186/s12934-019-1271-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 12/14/2019] [Indexed: 11/29/2022] Open
Abstract
Background Diacetyl provides the buttery aroma in products such as butter and margarine. It can be made via a harsh set of chemical reactions from sugarcane bagasse, however, in dairy products it is normally formed spontaneously from α-acetolactate, a compound generated by selected lactic acid bacteria in the starter culture used. Due to its bacteriostatic properties, it is difficult to achieve high levels of diacetyl by fermentation. Here we present a novel strategy for producing diacetyl based on whole-cell catalysis, which bypasses the toxic effects of diacetyl. Results By expressing a robust α-acetolactate synthase (ALS) in a metabolically optimized Lactococcus lactis strain we obtained a whole-cell biocatalyst that efficiently converted pyruvate into α-acetolactate. After process optimization, we achieved a titer for α-acetolactate of 172 ± 2 mM. Subsequently we used a two-stage production setup, where pyruvate was produced by an engineered L. lactis strain and subsequently used as the substrate for the biocatalyst. Using this approach, 122 ± 5 mM and 113 ± 3 mM α-acetolactate could be made from glucose or lactose in dairy waste, respectively. The whole-cell biocatalyst was robust and fully active in crude fermentation broth containing pyruvate. Conclusions An efficient approach for converting sugar into α-acetolactate, via pyruvate, was developed and tested successfully. Due to the anaerobic conditions used for the biotransformation, little diacetyl was generated, and this allowed for efficient biotransformation of pyruvate into α-acetolactate, with the highest titers reported to date. The use of a two-step procedure for producing α-acetolactate, where non-toxic pyruvate first is formed, and subsequently converted into α-acetolactate, also simplified the process optimization. We conclude that whole cell catalysis is suitable for converting lactose in dairy waste into α-acetolactate, which favors resource utilization.
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Affiliation(s)
- Robin Dorau
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Lin Chen
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Jianming Liu
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
| | - Christian Solem
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
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Liu J, Chan SHJ, Chen J, Solem C, Jensen PR. Systems Biology - A Guide for Understanding and Developing Improved Strains of Lactic Acid Bacteria. Front Microbiol 2019; 10:876. [PMID: 31114552 PMCID: PMC6503107 DOI: 10.3389/fmicb.2019.00876] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 04/04/2019] [Indexed: 12/15/2022] Open
Abstract
Lactic Acid Bacteria (LAB) are extensively employed in the production of various fermented foods, due to their safe status, ability to affect texture and flavor and finally due to the beneficial effect they have on shelf-life. More recently, LAB have also gained interest as production hosts for various useful compounds, particularly compounds with sensitive applications, such as food ingredients and therapeutics. As for all industrial microorganisms, it is important to have a good understanding of the physiology and metabolism of LAB in order to fully exploit their potential, and for this purpose, many systems biology approaches are available. Systems metabolic engineering, an approach that combines optimization of metabolic enzymes/pathways at the systems level, synthetic biology as well as in silico model simulation, has been used to build microbial cell factories for production of biofuels, food ingredients and biochemicals. When developing LAB for use in foods, genetic engineering is in general not an accepted approach. An alternative is to screen mutant libraries for candidates with desirable traits using high-throughput screening technologies or to use adaptive laboratory evolution to select for mutants with special properties. In both cases, by using omics data and data-driven technologies to scrutinize these, it is possible to find the underlying cause for the desired attributes of such mutants. This review aims to describe how systems biology tools can be used for obtaining both engineered as well as non-engineered LAB with novel and desired properties.
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Affiliation(s)
- Jianming Liu
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark.,Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Siu Hung Joshua Chan
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO, United States
| | - Jun Chen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Christian Solem
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
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Ricciardi A, Zotta T, Ianniello RG, Boscaino F, Matera A, Parente E. Effect of Respiratory Growth on the Metabolite Production and Stress Robustness of Lactobacillus casei N87 Cultivated in Cheese Whey Permeate Medium. Front Microbiol 2019; 10:851. [PMID: 31068919 PMCID: PMC6491770 DOI: 10.3389/fmicb.2019.00851] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/02/2019] [Indexed: 01/02/2023] Open
Abstract
Cheese whey permeate (WP) is a low-cost feedstock used for the production of biomass and metabolites from several lactic acid bacteria (LAB) strains. In this study, Lactobacillus casei N87 was cultivated in an optimized WP medium (WPM) to evaluate the effect of anaerobic and respiratory conditions on the growth performances (kinetics, biomass yield), consumption of sugars (lactose, galactose, glucose) and citrate, metabolite production [organic acids, volatile organic compounds (VOCs)] and stress survival (oxidative, heat, freezing, freeze-drying). The transcription of genes involved in the main pathways for pyruvate conversion was quantified through Real Time-PCR to elucidate the metabolic shifts due to respiratory state. Cultivation in WPM induced a diauxic growth in both anaerobic and respiratory conditions, and L. casei N87 effectively consumed the lactose and galactose present in WPM. Genomic information suggested that membrane PTS system and tagatose-6-P pathway mediated the metabolism of lactose and galactose in L. casei N87. Respiration did not affect specific growth rate and biomass production, but significantly altered the pyruvate conversion pathways, reducing lactate accumulation and promoting the formation of acetate, acetoin and diacetyl to ensure the redox balance. Ethanol was not produced under either cultivation. Pyruvate oxidase (pox), acetate kinase (ack), α-acetolactate decarboxylase (ald), acetolactate synthase (als) and oxaloacetate decarboxylase (oad) genes were up-regulated under respiration, while L-lactate dehydrogenase (ldh), pyruvate formate lyase (pfl), pyruvate carboxylase (pyc), and phosphate acetyltransferase (pta) were down regulated by oxygen. Transcription analysis was consistent with metabolite production, confirming that POX-ACK and ALS-ALD were the alternative pathways activated under aerobic cultivation. Respiratory growth affected the production of volatile compounds useful for the development of aroma profile in several fermented foods, and promoted the survival of L. casei N87 to oxidative stresses and long-term storage. This study confirmed that the respiration-based technology coupled with cultivation on low-cost medium may be effectively exploited to produce competitive and functional starter and/or adjunct cultures. Our results, additionally, provided further information on the activation and regulation of metabolic pathways in homofermentative LAB grown under respiratory promoting conditions.
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Affiliation(s)
- Annamaria Ricciardi
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy
| | - Teresa Zotta
- Istituto di Scienze dell'Alimentazione - Consiglio Nazionale delle Ricerche (CNR), Avellino, Italy
| | - Rocco Gerardo Ianniello
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy
| | - Floriana Boscaino
- Istituto di Scienze dell'Alimentazione - Consiglio Nazionale delle Ricerche (CNR), Avellino, Italy
| | - Attilio Matera
- Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy
| | - Eugenio Parente
- Dipartimento di Scienze, Università degli Studi della Basilicata, Potenza, Italy
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Braga A, Guerreiro C, Belo I. Generation of Flavors and Fragrances Through Biotransformation and De Novo Synthesis. FOOD BIOPROCESS TECH 2018; 11:2217-28. [DOI: 10.1007/s11947-018-2180-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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14
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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] [What about the content of this article? (0)] [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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Roncal T, Caballero S, Díaz de Guereñu MDM, Rincón I, Prieto-Fernández S, Ochoa-Gómez JR. Efficient production of acetoin by fermentation using the newly isolated mutant strain Lactococcus lactis subsp. lactis CML B4. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.04.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Liu J, Chan SHJ, Brock-Nannestad T, Chen J, Lee SY, Solem C, Jensen PR. Combining metabolic engineering and biocompatible chemistry for high-yield production of homo-diacetyl and homo-(S,S)-2,3-butanediol. Metab Eng 2016; 36:57-67. [DOI: 10.1016/j.ymben.2016.02.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/10/2016] [Accepted: 02/23/2016] [Indexed: 10/22/2022]
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Anasontzis GE, Kourtoglou E, Villas-Boâs SG, Hatzinikolaou DG, Christakopoulos P. Metabolic Engineering of Fusarium oxysporum to Improve Its Ethanol-Producing Capability. Front Microbiol 2016; 7:632. [PMID: 27199958 PMCID: PMC4854878 DOI: 10.3389/fmicb.2016.00632] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022] Open
Abstract
Fusarium oxysporum is one of the few filamentous fungi capable of fermenting ethanol directly from plant cell wall biomass. It has the enzymatic toolbox necessary to break down biomass to its monosaccharides and, under anaerobic and microaerobic conditions, ferments them to ethanol. Although these traits could enable its use in consolidated processes and thus bypass some of the bottlenecks encountered in ethanol production from lignocellulosic material when Saccharomyces cerevisiae is used—namely its inability to degrade lignocellulose and to consume pentoses—two major disadvantages of F. oxysporum compared to the yeast—its low growth rate and low ethanol productivity—hinder the further development of this process. We had previously identified phosphoglucomutase and transaldolase, two major enzymes of glucose catabolism and the pentose phosphate pathway, as possible bottlenecks in the metabolism of the fungus and we had reported the effect of their constitutive production on the growth characteristics of the fungus. In this study, we investigated the effect of their constitutive production on ethanol productivity under anaerobic conditions. We report an increase in ethanol yield and a concomitant decrease in acetic acid production. Metabolomics analysis revealed that the genetic modifications applied did not simply accelerate the metabolic rate of the microorganism; they also affected the relative concentrations of the various metabolites suggesting an increased channeling toward the chorismate pathway, an activation of the γ-aminobutyric acid shunt, and an excess in NADPH regeneration.
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Affiliation(s)
- George E Anasontzis
- Microbial Biotechnology Unit, Sector of Botany, Department of Biology, National and Kapodistrian University of Athens Zografou, Greece
| | - Elisavet Kourtoglou
- BIOtechMASS Unit, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens Zografou, Greece
| | - Silas G Villas-Boâs
- Centre for Microbial Innovation, School of Biological Sciences, University of Auckland Auckland, New Zealand
| | - Dimitris G Hatzinikolaou
- Microbial Biotechnology Unit, Sector of Botany, Department of Biology, National and Kapodistrian University of Athens Zografou, Greece
| | - Paul Christakopoulos
- Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology Luleå, Sweden
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Lehtovirta-Morley LE, Sayavedra-Soto LA, Gallois N, Schouten S, Stein LY, Prosser JI, Nicol GW. Identifying Potential Mechanisms Enabling Acidophily in the Ammonia-Oxidizing Archaeon "Candidatus Nitrosotalea devanaterra". Appl Environ Microbiol 2016; 82:2608-19. [PMID: 26896134 DOI: 10.1128/AEM.04031-15] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/13/2016] [Indexed: 01/11/2023] Open
Abstract
Ammonia oxidation is the first and rate-limiting step in nitrification and is dominated by two distinct groups of microorganisms in soil: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). AOA are often more abundant than AOB and dominate activity in acid soils. The mechanism of ammonia oxidation under acidic conditions has been a long-standing paradox. While high rates of ammonia oxidation are frequently measured in acid soils, cultivated ammonia oxidizers grew only at near-neutral pH when grown in standard laboratory culture. Although a number of mechanisms have been demonstrated to enable neutrophilic AOB growth at low pH in the laboratory, these have not been demonstrated in soil, and the recent cultivation of the obligately acidophilic ammonia oxidizer “Candidatus Nitrosotalea devanaterra” provides a more parsimonious explanation for the observed high rates of activity. Analysis of the sequenced genome, transcriptional activity, and lipid content of “Ca. Nitrosotalea devanaterra” reveals that previously proposed mechanisms used by AOB for growth at low pH are not essential for archaeal ammonia oxidation in acidic environments. Instead, the genome indicates that “Ca. Nitrosotalea devanaterra” contains genes encoding both a predicted high-affinity substrate acquisition system and potential pH homeostasis mechanisms absent in neutrophilic AOA. Analysis of mRNA revealed that candidate genes encoding the proposed homeostasis mechanisms were all expressed during acidophilic growth, and lipid profiling by high-performance liquid chromatography–mass spectrometry (HPLC-MS) demonstrated that the membrane lipids of “Ca. Nitrosotalea devanaterra” were not dominated by crenarchaeol, as found in neutrophilic AOA. This study for the first time describes a genome of an obligately acidophilic ammonia oxidizer and identifies potential mechanisms enabling this unique phenotype for future biochemical characterization.
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Zhang L, Zhang Y, Liu Q, Meng L, Hu M, Lv M, Li K, Gao C, Xu P, Ma C. Production of diacetyl by metabolically engineered Enterobacter cloacae. Sci Rep 2015; 5:9033. [PMID: 25761989 DOI: 10.1038/srep09033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/11/2015] [Indexed: 11/21/2022] Open
Abstract
Diacetyl, a high value product that can be extensively used as a food ingredient, could be produced from the non-enzymatic oxidative decarboxylation of α-acetolactate during 2,3-butanediol fermentation. In this study, the 2,3-butanediol biosynthetic pathway in Enterobacter cloacae subsp. dissolvens strain SDM, a good candidate for microbial 2,3-butanediol production, was reconstructed for diacetyl production. To enhance the accumulation of the precursor of diacetyl, the α-acetolactate decarboxylase encoding gene (budA) was knocked out in strain SDM. Subsequently, the two diacetyl reductases DR-I (gdh) and DR-II (budC) encoding genes were inactivated in strain SDM individually or in combination to decrease the reduction of diacetyl. Although the engineered strain E. cloacae SDM (ΔbudAΔbudC) was found to have a good ability for diacetyl production, more α-acetolactate than diacetyl was produced simultaneously. In order to enhance the nonenzymatic oxidative decarboxylation of α-acetolactate to diacetyl, 20 mM Fe3+ was added to the fermentation broth at the optimal time. In the end, by using the metabolically engineered strain E. cloacae SDM (ΔbudAΔbudC), diacetyl at a concentration of 1.45 g/L was obtained with a high productivity (0.13 g/(L·h)). The method developed here may be a promising process for biotechnological production of diacetyl.
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Zhang X, Rao Z, Li J, Zhou J, Yang T, Xu M, Bao T, Zhao X. Improving the acidic stability of Staphylococcus aureus α-acetolactate decarboxylase in Bacillus subtilis by changing basic residues to acidic residues. Amino Acids 2014; 47:707-17. [PMID: 25543264 DOI: 10.1007/s00726-014-1898-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 12/09/2014] [Indexed: 10/24/2022]
Abstract
The α-acetolactate decarboxylase (ALDC) can reduce diacetyl fleetly to promote mature beer. A safe strain Bacillus subtilis WB600 for high-yield production of ALDC was constructed with the ALDC gene saald from Staphylococcus aureus L3-15. SDS-PAGE analysis revealed that S. aureus α-acetolactate decarboxylase (SaALDC) was successfully expressed in recombinant B. siutilis strain. The enzyme SaALDC was purified using Ni-affinity chromatography and showed a maximum activity at 45 °C and pH 6.0. The values of K m and V max were 17.7 μM and 2.06 mM min(-1), respectively. Due to the unstable property of SaALDC at low pH conditions that needed in brewing process, site-directed mutagenesis was proposed for improving the acidic stability of SaALDC. Homology comparative modeling analysis showed that the mutation (K52D) gave rise to the negative-electrostatic potential on the surface of protein while the numbers of hydrogen bonds between the mutation site (N43D) and the around residues increased. Taken together the effect of mutation N43D-K52D, recombinant SaALDCN43D-K52D showed dramatically improved acidic stability with prolonged half-life of 3.5 h (compared to the WT of 1.5 h) at pH 4.0. In a 5-L fermenter, the recombinant B. subtilis strain that could over-express SaALDCN43D-K52D exhibited a high yield of 135.8 U mL(-1) of SaALDC activity, about 320 times higher comparing to 0.42 U mL(-1) of S. aureus L3-15. This work proposed a strategy for improving the acidic stability of SaALDC in the B. subtilis host.
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Affiliation(s)
- Xian Zhang
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, Jiangsu, China
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Abstract
In this study, Candida glabrata, an efficient pyruvate-producing strain, was metabolically engineered for the production of the food ingredient diacetyl. A diacetyl biosynthetic pathway was reconstructed based on genetic modifications and medium optimization. The former included (i) channeling carbon flux into the diacetyl biosynthetic pathway by amplification of acetolactate synthase, (ii) elimination of the branched pathway of α-acetolactate by deleting the ILV5 gene, and (iii) restriction of diacetyl degradation by deleting the BDH gene. The resultant strain showed an almost 1∶1 co-production of α-acetolactate and diacetyl (0.95 g L(-1)). Furthermore, addition of Fe3+ to the medium enhanced the conversion of α-acetolactate to diacetyl and resulted in a two-fold increase in diacetyl production (2.1 g L(-1)). In addition, increased carbon flux was further channeled into diacetyl biosynthetic pathway and a titer of 4.7 g L(-1) of diacetyl was achieved by altering the vitamin level in the flask culture. Thus, this study illustrates that C. glabrata could be tailored as an attractive platform for enhanced biosynthesis of beneficial products from pyruvate by metabolic engineering strategies.
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Affiliation(s)
- Xiang Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Nan Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Shubo Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
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Passerini D, Laroute V, Coddeville M, Le Bourgeois P, Loubière P, Ritzenthaler P, Cocaign-bousquet M, Daveran-mingot M. New insights into Lactococcus lactis diacetyl- and acetoin-producing strains isolated from diverse origins. Int J Food Microbiol 2013; 160:329-36. [DOI: 10.1016/j.ijfoodmicro.2012.10.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/17/2012] [Accepted: 10/24/2012] [Indexed: 11/21/2022]
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Affiliation(s)
- David R Nielsen
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Mucha M, Mielke Z. Structure and photochemistry of the methanol complexes with methylglyoxal and diacetyl: FTIR matrix isolation and theoretical study. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Zhao L, Bao Y, Wang J, Liu B, An L. Optimization and mechanism of diacetyl accumulation by Enterobacter aerogenes mutant UV-3. World J Microbiol Biotechnol 2009; 25:57-64. [DOI: 10.1007/s11274-008-9862-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Özkalp B, Özden B, Tuncer Y, Şanlibaba P, Akçelik M. Technological characterization of wild-typeLactococcus lactisstrains isolated from raw milk and traditional fermented milk products in Turkey. ACTA ACUST UNITED AC 2008. [DOI: 10.1051/lait:2007033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Abstract
Acetoin is an important physiological metabolite excreted by many microorganisms. The excretion of acetoin, which can be diagnosed by the Voges Proskauer test and serves as a microbial classification marker, has its vital physiological meanings to these microbes mainly including avoiding acification, participating in the regulation of NAD/NADH ratio, and storaging carbon. The well-known anabolism of acetoin involves alpha-acetolactat synthase and alpha-acetolactate decarboxylase; yet its catabolism still contains some differing views, although much attention has been focused on it and great advances have been achieved. Current findings in catabolite control protein A (CcpA) mediated carbon catabolite repression may provide a fuller understanding of the control mechanism in bacteria. In this review, we first examine the acetoin synthesis pathways and its physiological meanings and relevancies; then we discuss the relationship between the two conflicting acetoin cleavage pathways, the enzymes of the acetoin dehydrogenase enzyme system, major genes involved in acetoin degradation, and the CcpA mediated acetoin catabolite repression pathway; in the end we discuss the genetic engineering progresses concerning applications. To date, this is the first integrated review on acetoin metabolism in bacteria, especially with regard to catabolic aspects. The apperception of the generation and dissimilation of acetoin in bacteria will help provide a better understanding of microbial strategies in the struggle for resources, which will consequently better serve the utilization of these microbes.
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Affiliation(s)
- Zijun Xiao
- State Key Laboratory of Microbial Technology, Shandong University, People's Republic of China
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Mahmoud M, Gentil E, Robins RJ. Natural-abundance isotope ratio mass spectrometry as a means of evaluating carbon redistribution during glucose-citrate cofermentation by Lactococcus lactis. ACTA ACUST UNITED AC 2004; 271:4392-400. [PMID: 15560780 DOI: 10.1111/j.1432-1033.2004.04376.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The cometabolism of citrate and glucose by growing Lactococcus lactis ssp. lactis bv. diacetylactis was studied using a natural-abundance stable isotope technique. By a judicious choice of substrates differing slightly in their 13C/12C ratios, the simultaneous metabolism of citrate and glucose to a range of compounds was analysed. These end-products include lactate, acetate, formate, diacetyl and acetoin. All these products have pyruvate as a common intermediate. With the objective of estimating the degree to which glucose and citrate metabolism through pyruvate may be differentially regulated, the delta13C values of the products accumulated over a wide range of concentrations of citrate and glucose were compared. It was found that, whereas the relative accumulation of different products responds to both the substrate concentration and the ratio between the substrates, the delta13C values of the products primarily reflect the availability of the two substrates over the entire range examined. It can be concluded that in actively growing L. lactis the maintenance of pyruvate homeostasis takes precedence over the redox status of the cells as a regulatory factor.
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Affiliation(s)
- Mohamed Mahmoud
- Groupe de Fractionnement Isotopique de Métabolismes, Laboratoire d'Analyse Isotopique et Electrochimique de Métabolismes, Université de Nantes, France
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Roger O, Lavigne R, Mahmoud M, Buisson C, Onno B, Zhang BL, Robins RJ. Quantitative 2H NMR at natural abundance can distinguish the pathway used for glucose fermentation by lactic acid bacteria. J Biol Chem 2004; 279:24923-8. [PMID: 15051719 DOI: 10.1074/jbc.m401232200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For any given metabolic pathway, isotope redistribution coefficients (a(ij)) that characterize the specific derivation of each hydrogen atom can be defined. By using quantitative deuterium NMR, the redistribution of deuterium at natural abundance in lactic acid produced by the bacterial fermentation of glucose has been determined for each non-labile hydrogen atom of glucose or water and the hydrogen atoms of lactic acid. Distinct differences are observed in the lactic acid isolated from Lactococcus lactis and Leuconostoc mesenteroides that can be interpreted in terms of the different fermentative pathways used. Specifically, the affiliations observed between the H1, H3, and H4 positions of glucose with methyl and hydroxymethylene of lactic acid can give quantitative information on whether the glycolytic or the reductive pentose-phosphate pathway was involved in glucose catabolism.
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Affiliation(s)
- Olivier Roger
- Groupe de Fractionnement Isotopique de Métabolismes, Laboratoire d'Analyse Isotopique et Electrochimique de Métabolismes, CNRS UMR6006, Université de Nantes, BP 99208, F-44322 Nantes, France
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Current Awareness. FLAVOUR FRAG J 2001; 16:389-94. [DOI: 10.1002/ffj.963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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