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Decadt H, Weckx S, De Vuyst L. The microbial and metabolite composition of Gouda cheese made from pasteurized milk is determined by the processing chain. Int J Food Microbiol 2024; 412:110557. [PMID: 38237418 DOI: 10.1016/j.ijfoodmicro.2024.110557] [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: 08/17/2023] [Revised: 12/26/2023] [Accepted: 01/01/2024] [Indexed: 01/28/2024]
Abstract
Gouda cheeses of different production batches and ripening times often differ in metabolite composition, which may be due to the starter culture mixture applied or the growth of non-starter lactic acid bacteria (NSLAB) upon maturation. Therefore, a single Gouda cheese production batch was systematically investigated from the thermized milk to the mature cheeses, ripened for up to 100 weeks, to identify the main bacterial species and metabolites and their dynamics during the whole production and ripening. As this seemed to be starter culture strain- and NSLAB-dependent, it requested a detailed, longitudinal, and quantitative investigation. Hereto, microbial colony enumeration, high-throughput full-length 16S rRNA gene sequencing, and a metabolomic approach were combined. Culture-dependently, Lactococcus lactis was the most abundant species from its addition as part of the starter culture up to the first two months of cheese ripening. Afterward, the NSLAB Lacticaseibacillus paracasei became the main species during ripening. The milk was a possible inoculation source for the latter species, despite pasteurization. Culture-independently, the starter LAB Lactococcus cremoris and Lc. lactis were the most abundant species in the cheese core throughout the whole fermentation and ripening phases up to 100 weeks. The cheese rind from 40 until 100 weeks of ripening was characterized by a high relative abundance of the NSLAB Tetragenococcus halophilus and Loigolactobacillus rennini, which both came from the brine. These species were linked with the production of the biogenic amines cadaverine and putrescine. The most abundant volatile organic compound was acetoin, an indicator of citrate and lactose fermentation during the production day, whereas the concentrations of free amino acids were an indicator of the ripening time.
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Affiliation(s)
- Hannes Decadt
- Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Stefan Weckx
- Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Luc De Vuyst
- Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium.
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2
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Felczak MM, Bernard MP, TerAvest MA. Respiration is essential for aerobic growth of Zymomonas mobilis ZM4. mBio 2023; 14:e0204323. [PMID: 37909744 PMCID: PMC10746213 DOI: 10.1128/mbio.02043-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/27/2023] [Indexed: 11/03/2023] Open
Abstract
IMPORTANCE A key to producing next-generation biofuels is to engineer microbes that efficiently convert non-food materials into drop-in fuels, and to engineer microbes effectively, we must understand their metabolism thoroughly. Zymomonas mobilis is a bacterium that is a promising candidate biofuel producer, but its metabolism remains poorly understood, especially its metabolism when exposed to oxygen. Although Z. mobilis respires with oxygen, its aerobic growth is poor, and disruption of genes related to respiration counterintuitively improves aerobic growth. This unusual result has sparked decades of research and debate regarding the function of respiration in Z. mobilis. Here, we used a new set of mutants to determine that respiration is essential for aerobic growth and likely protects the cells from damage caused by oxygen. We conclude that the respiratory pathway of Z. mobilis should not be deleted from chassis strains for industrial production because this would yield a strain that is intolerant of oxygen, which is more difficult to manage in industrial settings.
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Affiliation(s)
- Magdalena M. Felczak
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Matthew P. Bernard
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
| | - Michaela A. TerAvest
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
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3
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López de Felipe F. Revised Aspects into the Molecular Bases of Hydroxycinnamic Acid Metabolism in Lactobacilli. Antioxidants (Basel) 2023; 12:1294. [PMID: 37372024 DOI: 10.3390/antiox12061294] [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: 05/21/2023] [Revised: 06/14/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Hydroxycinnamic acids (HCAs) are phenolic compounds produced by the secondary metabolism of edible plants and are the most abundant phenolic acids in our diet. The antimicrobial capacity of HCAs is an important function attributed to these phenolic acids in the defense of plants against microbiological threats, and bacteria have developed diverse mechanisms to counter the antimicrobial stress imposed by these compounds, including their metabolism into different microbial derivatives. The metabolism of HCAs has been intensively studied in Lactobacillus spp., as the metabolic transformation of HCAs by these bacteria contributes to the biological activity of these acids in plant and human habitats or to improve the nutritional quality of fermented foods. The main mechanisms known to date used by Lactobacillus spp. to metabolize HCAs are enzymatic decarboxylation and/or reduction. Here, recent advances in the knowledge regarding the enzymes that contribute to these two enzymatic conversions, the genes involved, their regulation and the physiological significance to lactobacilli are reviewed and critically discussed.
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Affiliation(s)
- Félix López de Felipe
- Laboratorio de Biotecnología Bacteriana, Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN), CSIC, José Antonio Novais 10, 28040 Madrid, Spain
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4
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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] [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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5
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Tian H, Jing Y, Yu H, Huang J, Yuan H, Lou X, Wang B, Xu Z, Chen C. Effect of alsD deletion and overexpression of nox and alsS on diacetyl and acetoin production by Lacticaseibacillus casei during milk fermentation. J Dairy Sci 2022; 105:2868-2879. [DOI: 10.3168/jds.2021-21163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 12/20/2021] [Indexed: 11/19/2022]
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6
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Li L, He Z, Liang T, Sheng T, Zhang F, Wu D, Ma F. Colonization of biofilm in wastewater treatment: A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118514. [PMID: 34808308 DOI: 10.1016/j.envpol.2021.118514] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 10/28/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
The attachment and colonization process of microorganisms on a carrier is an interdisciplinary research field. Through a series of physical, chemical, and biological actions, the microorganisms can eventually reproduce on the carrier. This article introduces biofilm start-up and its applications, and explores the current issues to look forward to future development directions. Firstly, the mechanism of microbial film formation is analyzed from the microbial community colonization and reproduction process. Secondly, when analyzing the factors influencing microbial membrane formation, the effect of microbial properties (e.g., genes, proteins, lipids) and external conditions (i.e., carrier, operating environment, and regulation mechanism among microbial communities) were discussed in depth. Aimed at exploring the mechanisms and influencing factors of biofilm start-up, this article proposes the application measures to strengthen this process. Finally, the problems encountered and the future development direction of the technology are analyzed and prospected.
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Affiliation(s)
- Lixin Li
- School of Environment and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China.
| | - Zhengming He
- School of Environment and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China
| | - Taojie Liang
- School of Environment and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China
| | - Tao Sheng
- School of Environment and Chemical Engineering, Heilongjiang University of Science and Technology, Harbin, 150022, China
| | - Fugui Zhang
- Longjiang Environmental Protection Group Co. Ltd., Harbin, 150050, China
| | - Dan Wu
- Longjiang Environmental Protection Group Co. Ltd., Harbin, 150050, China
| | - Fang Ma
- State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China
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7
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Bat-Erdene U, Billingsley JM, Turner WC, Lichman BR, Ippoliti FM, Garg NK, O'Connor SE, Tang Y. Cell-Free Total Biosynthesis of Plant Terpene Natural Products using an Orthogonal Cofactor Regeneration System. ACS Catal 2021; 11:9898-9903. [PMID: 35355836 DOI: 10.1021/acscatal.1c02267] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Here we report the one-pot, cell-free enzymatic synthesis of the plant monoterpene nepetalactol starting from the readily available geraniol. A pair of orthogonal cofactor regeneration systems permitted NAD+-dependent geraniol oxidation followed by NADPH-dependent reductive cyclization without isolation of intermediates. The orthogonal cofactor regeneration system maintained a high ratio of NAD+ to NADH and a low ratio of NADP+ to NADPH. The overall reaction contains four biosynthetic enzymes, including a soluble P450; and five accessory and cofactor regeneration enzymes. Furthermore, addition of a NAD+-dependent dehydrogenase to the one-pot mixture led to ~1 g/L of nepetalactone, the active cat- attractant in catnip.
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Affiliation(s)
- Undramaa Bat-Erdene
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - John M Billingsley
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - William C Turner
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA
| | - Benjamin R Lichman
- Centre for Agricultural Products, Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Francesca M Ippoliti
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
| | - Sarah E O'Connor
- Department of Natural Product Biosynthesis, Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA
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8
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Chen C, Cui Z, Zhao J, Li S, Ren X, Chen T, Wang Z. Improving diacetyl production in Corynebacterium glutamicum via modifying respiratory chain. J Biotechnol 2021; 332:20-28. [PMID: 33771625 DOI: 10.1016/j.jbiotec.2021.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/03/2021] [Accepted: 03/16/2021] [Indexed: 12/11/2022]
Abstract
To explore the suitability of Corynebacterium glutamicum as a chassis for diacetyl production from glucose, diacetyl metabolic pathway and the respiratory chain were linked to achieve redox balance. The carbon flux was redirected from pyruvate to diacetyl by overexpressing the α-acetolactate synthase, in combination with disruption the biosynthetic pathways of lactate, acetoin, 2,3-butanediol and acetate in C. glutamicum ATCC 13032. These modifications resulted in a sharp increase of the NADH/NAD+ ratio from 0.53 to 1.10, and produced 0.58 g/L diacetyl under aerobic conditions, representing a 58-fold increase over the wild type. Although the modification of the by-product pathways is an effective strategy, these disruption led to intracellular cofactor imbalance. NADH re-oxidization was further successfully solved by overexpressing of cytochrome bd oxidase. We constructed an efficient respiration-dependent cell factory by modification of the respiratory chain, improving diacetyl titer to 1.29 g/L in CGC11, decreased NADH/NAD+ ratio to 0.45, increased the ATP concentration from 8.51 to 10.64 μM/gDCW. To our best knowledge, this is the first report of diacetyl synthesis in C. glutamicum. Intracellular cofactor imbalance can be reduced by modification of the respiratory chain for production of diacetyl as well as other bio-based products with cofactor imbalance in C. glutamicum.
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Affiliation(s)
- Cong Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Zhenzhen Cui
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Juntao Zhao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Shuting Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Xiaoting Ren
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300350, China.
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9
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A cascade reaction for the synthesis of d-fagomine precursor revisited: Kinetic insight and understanding of the system. N Biotechnol 2021; 63:19-28. [PMID: 33640482 DOI: 10.1016/j.nbt.2021.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 02/21/2021] [Accepted: 02/22/2021] [Indexed: 11/23/2022]
Abstract
The synthesis of aldol adduct (3S,4R)-6-[(benzyloxycarbonyl)amino]-5,6-dideoxyhex-2-ulose, a precursor of the interesting dietary supplement, iminosugar d-fagomine, was studied in a cascade reaction with three enzymes starting from Cbz-N-3-aminopropanol. This system was studied previously using a statistical optimization method which enabled a 79 % yield of the aldol adduct with a 10 % yield of the undesired amino acid by-product. Here, a kinetic model of the cascade, including enzyme operational stability decay rate and the undesired overoxidation of the intermediate product, was developed. The validated model was instrumental in the optimization of the cascade reaction in the batch reactor. Simulations were carried out to determine the variables with the most significant impact on substrate conversion and product yield. As a result, process conditions were found that provided the aldol adduct in 92 % yield with only 0.7 % yield of the amino acid in a one-pot one-step reaction. Additionally, compared to previous work, this improved process outcome was achieved at lower concentrations of two enzymes used in the reaction. With this study the advantages are demonstrated of a modelling approach in developing complex biocatalytical processes. Mathematical models enable better understanding of the interactions of variables in the investigated system, reduce cost, experimental efforts in the lab and time necessary to obtain results since the simulations are carried out in silico.
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10
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Sano A, Takatera M, Kawai M, Ichinose R, Yamasaki-Yashiki S, Katakura Y. Suppression of lactate production by aerobic fed-batch cultures of Lactococcus lactis. J Biosci Bioeng 2020; 130:402-408. [PMID: 32669208 DOI: 10.1016/j.jbiosc.2020.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/01/2020] [Accepted: 06/07/2020] [Indexed: 11/20/2022]
Abstract
Aerobic fed-batch cultures were studied as a means of suppressing the production of lactate, which inhibits the growth of lactic acid bacteria (LAB). LAB produce lactate via lactate dehydrogenase (LDH), regenerating nicotinamide adenine dinucleotide (NAD+) consumed during glycolysis. Therefore, we focused on NADH oxidase (NOX), employing oxygen as an electron acceptor, as an alternative pathway to LDH for NAD+ regeneration. To avoid glucose repression of NOX and NAD+ consumption by glycolysis exceeding NAD+ regeneration by NOX, glucose was fed gradually. When Lactococcus lactis MG 1363 was aerobically fed at a specific growth rate of 0.2 h-1, the amount of lactate produced per amount of grown cell was reduced to 12% of that in anaerobic batch cultures. Metabolic flux analysis revealed that in addition to NAD+ regeneration by NOX, ATP acquisition by production of acetate and NAD+ regeneration by production of acetoin and 2,3-butanediol contributed to suppression of lactate production.
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Affiliation(s)
- Anna Sano
- Graduate School of Science and Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
| | - Misato Takatera
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
| | - Mio Kawai
- Graduate School of Science and Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
| | - Ryo Ichinose
- Graduate School of Science and Engineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
| | - Shino Yamasaki-Yashiki
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
| | - Yoshio Katakura
- Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate, Suita, Osaka 564-8680, Japan.
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11
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Liu L, Tang MC, Tang Y. Fungal Highly Reducing Polyketide Synthases Biosynthesize Salicylaldehydes That Are Precursors to Epoxycyclohexenol Natural Products. J Am Chem Soc 2019; 141:19538-19541. [PMID: 31790246 DOI: 10.1021/jacs.9b09669] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fungal highly reducing polyketide synthases (HRPKSs) are highly programmed multidomain enzymes that synthesize reduced polyketide structures. Recent reports indicated salicylaldehydes are synthesized by HRPKS biosynthetic gene clusters, which are unexpected based on known enzymology of HRPKSs. Using genome mining of a Trichoderma virens HRPKS gene cluster that encodes a number of redox enzymes, we uncover the strategy used by HRPKS pathways in the biosynthesis of aromatic products such as salicylaldehyde 4, which can be oxidatively modified to the epoxycyclohexanol natural product trichoxide 1. We show selective β-hydroxyl groups in the linear HRPKS product are individually reoxidized to β-ketones by short-chain dehydrogenase/reductase enzymes, which enabled intramolecular aldol condensation and aromatization. Our work expands the chemical space of natural products accessible through HRPKS pathways.
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Affiliation(s)
- Ling Liu
- Department of Chemical and Biomolecular Engineering , University of California , Los Angeles , California 90095 , United States.,State Key Laboratory of Mycology , Institute of Microbiology, Chinese Academy of Sciences , Beijing 100101 , P.R. China
| | - Man-Cheng Tang
- Department of Chemical and Biomolecular Engineering , University of California , Los Angeles , California 90095 , United States
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering , University of California , Los Angeles , California 90095 , United States.,Department of Chemistry and Biochemistry , University of California , Los Angeles , California 90095 , United States
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12
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Valentino H, Sobrado P. Performing anaerobic stopped-flow spectrophotometry inside of an anaerobic chamber. Methods Enzymol 2019; 620:51-88. [PMID: 31072501 DOI: 10.1016/bs.mie.2019.03.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The catalytic cycle of most flavin-dependent enzymes can be divided into oxidative and reductive half-reactions. Although some enzymes are oxidized by electron carrier proteins or organic compounds, many use oxygen as the final electron acceptor. In order to properly study the reductive half-reaction of flavin-dependent enzyme that react with oxygen, as in the case of oxidases and monooxygenases, it is necessary to establish anaerobic conditions that will only allow the reduction process to be monitored. The reduced flavoenzyme can be further studied by exposing it to oxygen to monitor the oxidative half-reaction. Anaerobic chambers provide an ideal environment for performing these experiments as they reliably maintain an anaerobic atmosphere inside a large workspace. A common tool used to study flavin-dependent enzymes is the stopped-flow spectrophotometry. This chapter describes methods for performing stopped-flow experiments in an anaerobic chamber. We include information about the chamber components, setting up a stopped-flow spectrophotometer inside of a chamber, preparing anaerobic solutions, and performing experiments to measure the reductive and oxidative half-reactions of flavin-dependent monooxygenases.
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Affiliation(s)
- Hannah Valentino
- Department of Biochemistry, Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States
| | - Pablo Sobrado
- Department of Biochemistry, Center for Drug Discovery, Virginia Tech, Blacksburg, VA, United States.
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13
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Chen C, Long L, Zhang F, Chen Q, Chen C, Yu X, Liu Q, Bao J, Long Z. Antifungal activity, main active components and mechanism of Curcuma longa extract against Fusarium graminearum. PLoS One 2018; 13:e0194284. [PMID: 29543859 PMCID: PMC5854386 DOI: 10.1371/journal.pone.0194284] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 02/28/2018] [Indexed: 11/19/2022] Open
Abstract
Curcuma longa possesses powerful antifungal activity, as demonstrated in many studies. In this study, the antifungal spectrum of Curcuma longa alcohol extract was determined, and the resulting EC50 values (mg/mL) of its extract on eleven fungi, including Fusarium graminearum, Fusarium chlamydosporum, Alternaria alternate, Fusarium tricinctum, Sclerotinia sclerotiorum, Botrytis cinerea, Fusarium culmorum, Rhizopus oryzae, Cladosporium cladosporioides, Fusarium oxysporum and Colletotrichum higginsianum, were 0.1088, 0.1742, 0.1888, 0.2547, 0.3135, 0.3825, 0.4229, 1.2086, 4.5176, 3.8833 and 5.0183, respectively. Among them, F. graminearum was selected to determine the inhibitory effects of the compounds (including curdione, isocurcumenol, curcumenol, curzerene, β-elemene, curcumin, germacrone and curcumol) derived from Curcuma longa. In addition, the antifungal activities of curdione, curcumenol, curzerene, curcumol and isocurcumenol and the synergies of the complexes of curdione and seven other chemicals were investigated. Differential proteomics of F. graminearum was also compared, and at least 2021 reproducible protein spots were identified. Among these spots, 46 were classified as differentially expressed proteins, and these proteins are involved in energy metabolism, tRNA synthesis and glucose metabolism. Furthermore, several fungal physiological differences were also analysed. The antifungal effect included fungal cell membrane disruption and inhibition of ergosterol synthesis, respiration, succinate dehydrogenase (SDH) and NADH oxidase.
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Affiliation(s)
- Ciqiong Chen
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Li Long
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Fusheng Zhang
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Qin Chen
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Cheng Chen
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Xiaorui Yu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Qingya Liu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Jinku Bao
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Zhangfu Long
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
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Delpech P, Rifa E, Ball G, Nidelet S, Dubois E, Gagne G, Montel MC, Delbès C, Bornes S. New Insights into the Anti-pathogenic Potential of Lactococcus garvieae against Staphylococcus aureus Based on RNA Sequencing Profiling. Front Microbiol 2017; 8:359. [PMID: 28337182 PMCID: PMC5340753 DOI: 10.3389/fmicb.2017.00359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 02/21/2017] [Indexed: 11/13/2022] Open
Abstract
The bio-preservation potential of Lactococcus garvieae lies in its capacity to inhibit the growth of staphylococci, especially Staphylococcus aureus, in dairy products and in vitro. In vitro, inhibition is modulated by the level of aeration, owing to hydrogen peroxide (H2O2) production by L. garvieae under aeration. The S. aureus response to this inhibition has already been studied. However, the molecular mechanisms of L. garvieae underlying the antagonism against S. aureus have never been explored. This study provides evidence of the presence of another extracellular inhibition effector in vitro. This effector was neither a protein, nor a lipid, nor a polysaccharide, nor related to an L-threonine deficiency. To better understand the H2O2-related inhibition mechanism at the transcriptome level and to identify other mechanisms potentially involved, we used RNA sequencing to determine the transcriptome response of L. garvieae to different aeration levels and to the presence or absence of S. aureus. The L. garvieae transcriptome differed radically between different aeration levels mainly in biological processes related to fundamental functions and nutritional adaptation. The transcriptomic response of L. garvieae to aeration level differed according to the presence or absence of S. aureus. The higher concentration of H2O2 with high aeration was not associated with a higher expression of L. garvieae H2O2-synthesis genes (pox, sodA, and spxA1) but rather with a repression of L. garvieae H2O2-degradation genes (trxB1, ahpC, ahpF, and gpx). We showed that L. garvieae displayed an original, previously undiscovered, H2O2 production regulation mechanism among bacteria. In addition to the key factor H2O2, the involvement of another extracellular effector in the antagonism against S. aureus was shown. Future studies should explore the relation between H2O2-metabolism, H2O2-producing LAB and the pathogen they inhibit. The nature of the other extracellular effector should also be determined.
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Affiliation(s)
- Pierre Delpech
- Université Clermont Auvergne, INRA, UMRF Aurillac, France
| | - Etienne Rifa
- Université Clermont Auvergne, INRA, UMRF Aurillac, France
| | - Graham Ball
- John van Geest Cancer Research Centre, School of Science and Technology, Nottingham Trent University Nottingham, UK
| | - Sabine Nidelet
- Montpellier GenomiX, Institut de Génomique Fonctionnelle Montpellier, France
| | - Emeric Dubois
- Montpellier GenomiX, Institut de Génomique Fonctionnelle Montpellier, France
| | | | | | - Céline Delbès
- Université Clermont Auvergne, INRA, UMRF Aurillac, France
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Titov DV, Cracan V, Goodman RP, Peng J, Grabarek Z, Mootha VK. Complementation of mitochondrial electron transport chain by manipulation of the NAD+/NADH ratio. Science 2016; 352:231-5. [PMID: 27124460 DOI: 10.1126/science.aad4017] [Citation(s) in RCA: 281] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 01/25/2016] [Indexed: 12/16/2022]
Abstract
A decline in electron transport chain (ETC) activity is associated with many human diseases. Although diminished mitochondrial adenosine triphosphate production is recognized as a source of pathology, the contribution of the associated reduction in the ratio of the amount of oxidized nicotinamide adenine dinucleotide (NAD(+)) to that of its reduced form (NADH) is less clear. We used a water-forming NADH oxidase from Lactobacillus brevis (LbNOX) as a genetic tool for inducing a compartment-specific increase of the NAD(+)/NADH ratio in human cells. We used LbNOX to demonstrate the dependence of key metabolic fluxes, gluconeogenesis, and signaling on the cytosolic or mitochondrial NAD(+)/NADH ratios. Expression of LbNOX in the cytosol or mitochondria ameliorated proliferative and metabolic defects caused by an impaired ETC. The results underscore the role of reductive stress in mitochondrial pathogenesis and demonstrate the utility of targeted LbNOX for direct, compartment-specific manipulation of redox state.
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Affiliation(s)
- Denis V Titov
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. Department of Systems Biology, Harvard Medical School, Boston, MA, USA. Broad Institute, Cambridge, MA, USA
| | - Valentin Cracan
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. Department of Systems Biology, Harvard Medical School, Boston, MA, USA. Broad Institute, Cambridge, MA, USA
| | - Russell P Goodman
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA
| | - Jun Peng
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Zenon Grabarek
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. Broad Institute, Cambridge, MA, USA
| | - Vamsi K Mootha
- Howard Hughes Medical Institute and Department of Molecular Biology, Massachusetts General Hospital, Boston, MA, USA. Department of Systems Biology, Harvard Medical School, Boston, MA, USA. Broad Institute, Cambridge, MA, USA.
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16
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Kim JW, Kim J, Seo SO, Kim KH, Jin YS, Seo JH. Enhanced production of 2,3-butanediol by engineered Saccharomyces cerevisiae through fine-tuning of pyruvate decarboxylase and NADH oxidase activities. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:265. [PMID: 27990176 PMCID: PMC5148919 DOI: 10.1186/s13068-016-0677-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/01/2016] [Indexed: 05/22/2023]
Abstract
BACKGROUND 2,3-Butanediol (2,3-BD) is a promising compound for various applications in chemical, cosmetic, and agricultural industries. Pyruvate decarboxylase (Pdc)-deficient Saccharomyces cerevisiae is an attractive host strain for producing 2,3-BD because a large amount of pyruvate could be shunted to 2,3-BD production instead of ethanol synthesis. However, 2,3-BD yield, productivity, and titer by engineered yeast were inferior to native bacterial producers because of the following metabolic limitations. First, the Pdc-deficient yeast showed growth defect due to a shortage of C2-compounds. Second, redox imbalance during the 2,3-BD production led to glycerol formation that lowered the yield. RESULTS To overcome these problems, the expression levels of Pdc from a Crabtree-negative yeast were optimized in S. cerevisiae. Specifically, Candida tropicalis PDC1 (CtPDC1) was used to minimize the production of ethanol but maximize cell growth and 2,3-BD productivity. As a result, productivity of the BD5_G1CtPDC1 strain expressing an optimal level of Pdc was 2.3 folds higher than that of the control strain in flask cultivation. Through a fed-batch fermentation, 121.8 g/L 2,3-BD was produced in 80 h. NADH oxidase from Lactococcus lactis (noxE) was additionally expressed in the engineered yeast with an optimal activity of Pdc. The fed-batch fermentation with the optimized 2-stage aeration control led to production of 154.3 g/L 2,3-BD in 78 h. The overall yield of 2,3-BD was 0.404 g 2,3-BD/g glucose which corresponds to 80.7% of theoretical yield. CONCLUSIONS A massive metabolic shift in the engineered S. cerevisiae (BD5_G1CtPDC1_nox) expressing NADH oxidase was observed, suggesting that redox imbalance was a major bottleneck for efficient production of 2,3-BD by engineered yeast. Maximum 2,3-BD titer in this study was close to the highest among the reported microbial production studies. The results demonstrate that resolving both C2-compound limitation and redox imbalance is critical to increase 2,3-BD production in the Pdc-deficient S. cerevisiae. Our strategy to express fine-tuned PDC and noxE could be applicable not only to 2,3-BD production, but also other chemical production systems using Pdc-deficient S. cerevisiae.
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Affiliation(s)
- Jin-Woo Kim
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul, 151-921 Republic of Korea
| | - Jungyeon Kim
- School of Life Sciences and Biotechnology, Korea University, Seoul, 136-713 Republic of Korea
| | - Seung-Oh Seo
- Department of Food Science and Human Nutrition, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Kyoung Heon Kim
- School of Life Sciences and Biotechnology, Korea University, Seoul, 136-713 Republic of Korea
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Jin-Ho Seo
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, Seoul National University, Seoul, 151-921 Republic of Korea
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17
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Yang T, Rao Z, Hu G, Zhang X, Liu M, Dai Y, Xu M, Xu Z, Yang ST. Metabolic engineering of Bacillus subtilis for redistributing the carbon flux to 2,3-butanediol by manipulating NADH levels. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:129. [PMID: 26312069 PMCID: PMC4549875 DOI: 10.1186/s13068-015-0320-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/18/2015] [Indexed: 05/28/2023]
Abstract
BACKGROUND Acetoin reductase (Acr) catalyzes the conversion of acetoin to 2,3-butanediol (2,3-BD) with concomitant oxidation of NADH to NAD(+). Therefore, intracellular 2,3-BD production is likely governed by the quantities of rate-limiting factor(s) Acr and/or NADH. Previously, we showed that a high level of Acr was beneficial for 2,3-BD accumulation. RESULTS Metabolic engineering strategies were proposed to redistribute carbon flux to 2,3-BD by manipulating NADH levels. The disruption of NADH oxidase (YodC, encoded by yodC) by insertion of a formate dehydrogenase gene in Bacillus subtilis was more efficient for enhancing 2,3-BD production and decreasing acetoin formation than the disruption of YodC by the insertion of a Cat expression cassette. This was because the former resulted in the recombinant strain AFY in which an extra NADH regeneration system was introduced and NADH oxidase was disrupted simultaneously. On fermentation by strain AFY, the highest 2,3-BD concentration increased by 19.9 % while the acetoin titer decreased by 71.9 %, relative to the parental strain. However, the concentration of lactate, the main byproduct, increased by 47.2 %. To further improve carbon flux and NADH to 2,3-BD, the pathway to lactate was blocked using the insertional mutation technique to disrupt the lactate dehydrogenase gene ldhA. The resultant engineered strain B. subtilis AFYL could efficiently convert glucose into 2,3-BD with little acetoin and lactate accumulation. CONCLUSIONS Through increasing the availability of NADH and decreasing the concentration of unwanted byproducts, this work demonstrates an important strategy in the metabolic engineering of 2,3-BD production by integrative recombinant hosts.
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Affiliation(s)
- Taowei Yang
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Zhiming Rao
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
- />School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Guiyuan Hu
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Xian Zhang
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Mei Liu
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Yue Dai
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Meijuan Xu
- />The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Zhenghong Xu
- />Laboratory of Pharmaceutical Engineering, School of Pharmaceutical Science, Jiangnan University, Wuxi, 214122 Jiangsu People’s Republic of China
| | - Shang-Tian Yang
- />Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210 USA
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18
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Li N, Wang Y, Zhu P, Liu Z, Guo B, Ren J. Improvement of exopolysaccharide production in Lactobacillus casei LC2W by overexpression of NADH oxidase gene. Microbiol Res 2015; 171:73-7. [DOI: 10.1016/j.micres.2014.12.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 11/22/2014] [Accepted: 12/14/2014] [Indexed: 10/24/2022]
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19
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Sudar M, Findrik Z, Vasić-Rački Đ, Soler A, Clapés P. A new concept for production of (3S,4R)-6-[(benzyloxycarbonyl)amino]-5,6-dideoxyhex-2-ulose, a precursor of d-fagomine. RSC Adv 2015. [DOI: 10.1039/c5ra14414k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A novel cascade reaction combining three enzymes in one pot for the production of aldol adduct (3S,4R)-6-[(benzyloxycarbonyl)amino]-5,6-dideoxyhex-2-ulose was studied and 79% yield on aldol adduct was achieved in the batch reactor.
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Affiliation(s)
- Martina Sudar
- University of Zagreb
- Faculty of Chemical Engineering and Technology
- HR-10000 Zagreb
- Croatia
| | - Zvjezdana Findrik
- University of Zagreb
- Faculty of Chemical Engineering and Technology
- HR-10000 Zagreb
- Croatia
| | - Đurđa Vasić-Rački
- University of Zagreb
- Faculty of Chemical Engineering and Technology
- HR-10000 Zagreb
- Croatia
| | - Anna Soler
- Institute of Advanced Chemistry of Catalonia
- Biotransformation and Bioactive Molecules Group
- IQAC-CSIC
- 08034 Barcelona
- Spain
| | - Pere Clapés
- Institute of Advanced Chemistry of Catalonia
- Biotransformation and Bioactive Molecules Group
- IQAC-CSIC
- 08034 Barcelona
- Spain
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20
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Expression of the NAD-dependent FDH1 β-subunit from Methylobacterium extorquens AM1 in Escherichia coli and its characterization. BIOTECHNOL BIOPROC E 2014. [DOI: 10.1007/s12257-014-0126-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Efficient whole-cell biocatalyst for acetoin production with NAD+ regeneration system through homologous co-expression of 2,3-butanediol dehydrogenase and NADH oxidase in engineered Bacillus subtilis. PLoS One 2014; 9:e102951. [PMID: 25036158 PMCID: PMC4103878 DOI: 10.1371/journal.pone.0102951] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 06/24/2014] [Indexed: 01/19/2023] Open
Abstract
Acetoin (3-hydroxy-2-butanone), an extensively-used food spice and bio-based platform chemical, is usually produced by chemical synthesis methods. With increasingly requirement of food security and environmental protection, bio-fermentation of acetoin by microorganisms has a great promising market. However, through metabolic engineering strategies, the mixed acid-butanediol fermentation metabolizes a certain portion of substrate to the by-products of organic acids such as lactic acid and acetic acid, which causes energy cost and increases the difficulty of product purification in downstream processes. In this work, due to the high efficiency of enzymatic reaction and excellent selectivity, a strategy for efficiently converting 2,3-butandiol to acetoin using whole-cell biocatalyst by engineered Bacillus subtilis is proposed. In this process, NAD+ plays a significant role on 2,3-butanediol and acetoin distribution, so the NADH oxidase and 2,3-butanediol dehydrogenase both from B. subtilis are co-expressed in B. subtilis 168 to construct an NAD+ regeneration system, which forces dramatic decrease of the intracellular NADH concentration (1.6 fold) and NADH/NAD+ ratio (2.2 fold). By optimization of the enzymatic reaction and applying repeated batch conversion, the whole-cell biocatalyst efficiently produced 91.8 g/L acetoin with a productivity of 2.30 g/(L·h), which was the highest record ever reported by biocatalysis. This work indicated that manipulation of the intracellular cofactor levels was more effective than the strategy of enhancing enzyme activity, and the bioprocess for NAD+ regeneration may also be a useful way for improving the productivity of NAD+-dependent chemistry-based products.
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22
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23
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Korman TP, Sahachartsiri B, Li D, Vinokur JM, Eisenberg D, Bowie JU. A synthetic biochemistry system for the in vitro production of isoprene from glycolysis intermediates. Protein Sci 2014; 23:576-85. [PMID: 24623472 DOI: 10.1002/pro.2436] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 01/30/2014] [Accepted: 01/30/2014] [Indexed: 02/04/2023]
Abstract
The high yields required for the economical production of chemicals and fuels using microbes can be difficult to achieve due to the complexities of cellular metabolism. An alternative to performing biochemical transformations in microbes is to build biochemical pathways in vitro, an approach we call synthetic biochemistry. Here we test whether the full mevalonate pathway can be reconstituted in vitro and used to produce the commodity chemical isoprene. We construct an in vitro synthetic biochemical pathway that uses the carbon and ATP produced from the glycolysis intermediate phosphoenolpyruvate to run the mevalonate pathway. The system involves 12 enzymes to perform the complex transformation, while providing and balancing the ATP, NADPH, and acetyl-CoA cofactors. The optimized system produces isoprene from phosphoenolpyruvate in ∼100% molar yield. Thus, by inserting the isoprene pathway into previously developed glycolysis modules it may be possible to produce isoprene and other acetyl-CoA derived isoprenoids from glucose in vitro.
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Affiliation(s)
- Tyler P Korman
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics, Molecular Biology Institute, University of California, Los Angeles, California
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24
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Petschacher B, Staunig N, Müller M, Schürmann M, Mink D, De Wildeman S, Gruber K, Glieder A. Cofactor Specificity Engineering of Streptococcus mutans NADH Oxidase 2 for NAD(P)(+) Regeneration in Biocatalytic Oxidations. Comput Struct Biotechnol J 2014; 9:e201402005. [PMID: 24757503 PMCID: PMC3995211 DOI: 10.5936/csbj.201402005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 02/16/2014] [Accepted: 02/21/2014] [Indexed: 11/22/2022] Open
Abstract
Soluble water-forming NAD(P)H oxidases constitute a promising NAD(P)(+) regeneration method as they only need oxygen as cosubstrate and produce water as sole byproduct. Moreover, the thermodynamic equilibrium of O2 reduction is a valuable driving force for mostly energetically unfavorable biocatalytic oxidations. Here, we present the generation of an NAD(P)H oxidase with high activity for both cofactors, NADH and NADPH. Starting from the strictly NADH specific water-forming Streptococcus mutans NADH oxidase 2 several rationally designed cofactor binding site mutants were created and kinetic values for NADH and NADPH conversion were determined. Double mutant 193R194H showed comparable high rates and low K m values for NADPH (k cat 20 s(-1), K m 6 µM) and NADH (k cat 25 s(-1), K m 9 µM) with retention of 70% of wild type activity towards NADH. Moreover, by screening of a SeSaM library S. mutans NADH oxidase 2 variants showing predominantly NADPH activity were found, giving further insight into cofactor binding site architecture. Applicability for cofactor regeneration is shown for coupling with alcohol dehydrogenase from Sphyngobium yanoikuyae for 2-heptanone production.
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Affiliation(s)
- Barbara Petschacher
- Austrian Centre of Industrial Biotechnology GmbH, c/o Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Nicole Staunig
- Austrian Centre of Industrial Biotechnology GmbH, c/o Institute of Molecular Biosciences, University Graz, Humboldtstrasse 50/3, 8010 Graz, Austria
| | - Monika Müller
- DSM Innovative Synthesis B.V., P.O. Box 18, 6160 MD Geleen, Netherlands
| | - Martin Schürmann
- DSM Innovative Synthesis B.V., P.O. Box 18, 6160 MD Geleen, Netherlands
| | - Daniel Mink
- DSM Innovative Synthesis B.V., P.O. Box 18, 6160 MD Geleen, Netherlands
| | | | - Karl Gruber
- Austrian Centre of Industrial Biotechnology GmbH, c/o Institute of Molecular Biosciences, University Graz, Humboldtstrasse 50/3, 8010 Graz, Austria
| | - Anton Glieder
- Austrian Centre of Industrial Biotechnology GmbH, c/o Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
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25
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The rebalanced pathway significantly enhances acetoin production by disruption of acetoin reductase gene and moderate-expression of a new water-forming NADH oxidase in Bacillus subtilis. Metab Eng 2014; 23:34-41. [PMID: 24525333 DOI: 10.1016/j.ymben.2014.02.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 01/11/2014] [Accepted: 02/03/2014] [Indexed: 01/26/2023]
Abstract
Bacillus subtilis produces acetoin as a major extracellular product. However, the by-products of 2,3-butanediol, lactic acid and ethanol were accompanied in the NADH-dependent pathways. In this work, metabolic engineering strategies were proposed to redistribute the carbon flux to acetoin by manipulation the NADH levels. We first knocked out the acetoin reductase gene bdhA to block the main flux from acetoin to 2,3-butanediol. Then, among four putative candidates, we successfully screened an active water-forming NADH oxidase, YODC. Moderate-expression of YODC in the bdhA disrupted B. subtilis weakened the NADH-linked pathways to by-product pools of acetoin. Through these strategies, acetoin production was improved to 56.7g/l with an increase of 35.3%, while the production of 2,3-butanediol, lactic acid and ethanol were decreased by 92.3%, 70.1% and 75.0%, respectively, simultaneously the fermentation duration was decreased 1.7-fold. Acetoin productivity by B. subtilis was improved to 0.639g/(lh).
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26
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Ji XJ, Xia ZF, Fu NH, Nie ZK, Shen MQ, Tian QQ, Huang H. Cofactor engineering through heterologous expression of an NADH oxidase and its impact on metabolic flux redistribution in Klebsiella pneumoniae. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:7. [PMID: 23351660 PMCID: PMC3563507 DOI: 10.1186/1754-6834-6-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 01/23/2013] [Indexed: 05/10/2023]
Abstract
BACKGROUND Acetoin is an important bio-based platform chemical. However, it is usually existed as a minor byproduct of 2,3-butanediol fermentation in bacteria. RESULTS The present study reports introducing an exogenous NAD+ regeneration sysytem into a 2,3-butanediol producing strain Klebsiella pneumoniae to increse the accumulation of acetoin. Batch fermentation suggested that heterologous expression of the NADH oxidase in K. pneumoniae resulted in large decreases in the intracellular NADH concentration (1.4 fold) and NADH/NAD+ ratio (2.0 fold). Metabolic flux analysis revealed that fluxes to acetoin and acetic acid were enhanced, whereas, production of lactic acid and ethanol were decreased, with the accumualation of 2,3-butanediol nearly unaltered. By fed-batch culture of the recombinant, the highest reported acetoin production level (25.9 g/L) by Klebsiella species was obtained. CONCLUSIONS The present study indicates that microbial production of acetoin could be improved by decreasing the intracellular NADH/NAD+ ratio in K. pneumoniae. It demonstrated that the cofactor engineering method, which is by manipulating the level of intracellular cofactors to redirect cellular metabolism, could be employed to achieve a high efficiency of producing the NAD+-dependent microbial metabolite.
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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
| | - Zhi-Fang Xia
- 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
| | - Ning-Hua Fu
- 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
| | - Zhi-Kui Nie
- 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
| | - Meng-Qiu Shen
- 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
| | - Qian-Qian Tian
- 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
| | - He Huang
- 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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27
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Guo T, Kong J, Zhang L, Zhang C, Hu S. Fine tuning of the lactate and diacetyl production through promoter engineering in Lactococcus lactis. PLoS One 2012; 7:e36296. [PMID: 22558426 PMCID: PMC3338672 DOI: 10.1371/journal.pone.0036296] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 03/30/2012] [Indexed: 01/08/2023] Open
Abstract
Lactococcus lactis is a well-studied bacterium widely used in dairy fermentation and capable of producing metabolites with organoleptic and nutritional characteristics. For fine tuning of the distribution of glycolytic flux at the pyruvate branch from lactate to diacetyl and balancing the production of the two metabolites under aerobic conditions, a constitutive promoter library was constructed by randomizing the promoter sequence of the H2O-forming NADH oxidase gene in L. lactis. The library consisted of 30 promoters covering a wide range of activities from 7,000 to 380,000 relative fluorescence units using a green fluorescent protein as reporter. Eleven typical promoters of the library were selected for the constitutive expression of the H2O-forming NADH oxidase gene in L. lactis, and the NADH oxidase activity increased from 9.43 to 58.17-fold of the wild-type strain in small steps of activity change under aerobic conditions. Meanwhile, the lactate yield decreased from 21.15±0.08 mM to 9.94±0.07 mM, and the corresponding diacetyl production increased from 1.07±0.03 mM to 4.16±0.06 mM with the intracellular NADH/NAD+ ratios varying from 0.711±0.005 to 0.383±0.003. The results indicated that the reduced pyruvate to lactate flux was rerouted to the diacetyl with an almost linear flux variation via altered NADH/NAD+ ratios. Therefore, we provided a novel strategy to precisely control the pyruvate distribution for fine tuning of the lactate and diacetyl production through promoter engineering in L. lactis. Interestingly, the increased H2O-forming NADH oxidase activity led to 76.95% lower H2O2 concentration in the recombinant strain than that of the wild-type strain after 24 h of aerated cultivation. The viable cells were significantly elevated by four orders of magnitude within 28 days of storage at 4°C, suggesting that the increased enzyme activity could eliminate H2O2 accumulation and prolong cell survival.
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Affiliation(s)
| | - Jian Kong
- State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China
- * E-mail:
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Wang L, Chong H, Jiang R. Comparison of alkyl hydroperoxide reductase and two water-forming NADH oxidases from Bacillus cereus ATCC 14579. Appl Microbiol Biotechnol 2012; 96:1265-73. [PMID: 22311647 DOI: 10.1007/s00253-012-3919-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 01/16/2012] [Accepted: 01/19/2012] [Indexed: 10/14/2022]
Abstract
Bacillus cereus (B. cereus) is an ubiquitous facultative anaerobic bacterium, and its growth in aerobic environment correlates to the functions of its oxygen defense system. Water-forming NADH oxidase (nox-2) can catalyze the conversion of oxygen to water with concomitant NADH oxidation in anaerobic microorganisms. Here, we report the cloning and characterization of two annotated nox-2 s (nox-2(444) and nox-2(554)) from B. cereus ATCC 14579 and their comparison with another oxidative stress defense system alkyl hydroperoxide reductase (AhpR) from this microbe, which composed of two enzymes-hydrogen peroxide-forming NADH oxidase (nox-1) and peroxidase. Both nox-2 and AhpR catalyze the same reaction in the presence of oxygen. With the stimulation of exogenously added FAD, the maximum activity of nox-1, nox-2(444), and nox-2(554) could reach 27.7 U/mg, 22.9 U/mg, and 2.4 U/mg, respectively, at pH 7.0, 30 °C. Different from nox-1, both nox-2 s were thermotolerant enzymes and could maintain above 87% of their optimum activity at 80 °C, which was not found in other nox-2 s. As for operational stability, all are turnover-limited. Exogenously added reductive reagent dithiothreitol could dramatically increase the total turnover number of nox-2(444) and nox-2(554) by twofold and threefold, respectively, but had no effect on AhpR or nox-1.
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Affiliation(s)
- Liang Wang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore, 637459, Singapore
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Zhang YW, Tiwari MK, Gao H, Dhiman SS, Jeya M, Lee JK. Cloning and characterization of a thermostable H2O-forming NADH oxidase from Lactobacillus rhamnosus. Enzyme Microb Technol 2012; 50:255-62. [PMID: 22418266 DOI: 10.1016/j.enzmictec.2012.01.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 01/13/2012] [Accepted: 01/28/2012] [Indexed: 11/30/2022]
Abstract
NADH oxidase (Nox) catalyzes the conversion of NADH to NAD(+). A previously uncharacterized Nox gene (LrNox) was cloned from Lactobacillus rhamnosus and overexpressed in Escherichia coli BL21(DE3). Sequence analysis revealed an open reading frame of 1359 bp, capable of encoding a polypeptide of 453 amino acid residues. The molecular mass of the purified LrNox enzyme was estimated to be ~50 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 100 kDa by gel filtration chromatography, suggesting that the enzyme is a homodimer. The enzyme had optimal activity at pH 5.6 and temperature 65 °C, and k(cat)/K(m) of 3.77×10(7) s(-1) M(-1), the highest ever reported. Heat inactivation studies revealed that LrNox had high thermostability, with a half-life of 120 min at 80 °C. Molecular dynamics simulation studies shed light on the factors contributing to the high activity of LrNox. Although the properties of Nox from several microorganisms have been reported, this is the first report on the characterization of a recombinant H(2)O-forming Nox with high activity and thermostability. The characteristics of the LrNox enzyme could prove to be of interest in industrial applications such as NAD(+) regeneration.
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Affiliation(s)
- Ye-Wang Zhang
- Department of Chemical Engineering, Konkuk University, Seoul 143-701, Republic of Korea
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Identification of a conserved sequence in flavoproteins essential for the correct conformation and activity of the NADH oxidase NoxE of Lactococcus lactis. J Bacteriol 2011; 193:3000-8. [PMID: 21498647 DOI: 10.1128/jb.01466-10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Water-forming NADH oxidases (encoded by noxE, nox2, or nox) are flavoproteins generally implicated in the aerobic survival of microaerophilic bacteria, such as lactic acid bacteria. However, some natural Lactococcus lactis strains produce an inactive NoxE. We examined the role of NoxE in the oxygen tolerance of L. lactis in the rich synthetic medium GM17. Inactivation of noxE suppressed 95% of NADH oxidase activity but only slightly affected aerobic growth, oxidative stress resistance, and NAD regeneration. However, noxE inactivation strongly impaired oxygen consumption and mixed-acid fermentation. We found that the A303T mutation is responsible for the loss of activity of a naturally occurring variant of NoxE. Replacement of A303 with T or G or of G307 with S or A by site-directed mutagenesis led to NoxE aggregation and the total loss of activity. We demonstrated that L299 is involved in NoxE activity, probably contributing to positioning flavin adenine dinucleotide (FAD) in the active site. These residues are part of the strongly conserved sequence LA(T)XXAXXXG included in an alpha helix that is present in other flavoprotein disulfide reductase (FDR) family flavoproteins that display very similar three-dimensional structures.
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Michelon D, Abraham S, Ebel B, De Coninck J, Husson F, Feron G, Gervais P, Cachon R. Contribution of exofacial thiol groups in the reducing activity of Lactococcus lactis. FEBS J 2010; 277:2282-90. [PMID: 20423456 DOI: 10.1111/j.1742-4658.2010.07644.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lactococcus lactis can decrease the redox potential at pH 7 (E(h7)) from 200 to -200 mV in oxygen free Man-Rogosa-Sharpe media. Neither the consumption of oxidizing compounds or the release of reducing compounds during lactic acid fermentation were involved in the decrease in E(h7) by the bacteria. Thiol groups located on the bacterial cell surface appear to be the main components that are able to establish a greater exchange current between the Pt electrode and the bacteria. After the final E(h7) (-200 mV) was reached, only thiol-reactive reagents could restore the initial E(h7) value. Inhibition of the proton motive force showed no effect on maintaining the final E(h7) value. These results suggest that maintaining the exofacial thiol (-SH) groups in a reduced state does not depend on an active mechanism. Thiol groups appear to be displayed by membrane proteins or cell wall-bound proteins and may participate in protecting cells against oxidative stress.
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Affiliation(s)
- D Michelon
- Laboratoire de Génie des Procédés Microbiologiques et Alimentaires, AgroSup Dijon, Université de Bourgogne, Dijon, France
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NoxE NADH oxidase and the electron transport chain are responsible for the ability of Lactococcus lactis to decrease the redox potential of milk. Appl Environ Microbiol 2009; 76:1311-9. [PMID: 20038695 DOI: 10.1128/aem.02120-09] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The redox potential plays a major role in the microbial and sensorial quality of fermented dairy products. The redox potential of milk (around 400 mV) is mainly due to the presence of oxygen and many other oxidizing compounds. Lactococcus lactis has a strong ability to decrease the redox potential of milk to a negative value (-220 mV), but the molecular mechanisms of milk reduction have never been addressed. In this study, we investigated the impact of inactivation of genes encoding NADH oxidases (noxE and ahpF) and components of the electron transport chain (ETC) (menC and noxAB) on the ability of L. lactis to decrease the redox potential of ultrahigh-temperature (UHT) skim milk during growth under aerobic and anaerobic conditions. Our results revealed that elimination of oxygen is required for milk reduction and that NoxE is mainly responsible for the rapid removal of oxygen from milk before the exponential growth phase. The ETC also contributes slightly to oxygen consumption, especially during the stationary growth phase. We also demonstrated that the ETC is responsible for the decrease in the milk redox potential from 300 mV to -220 mV when the oxygen concentration reaches zero or under anaerobic conditions. This suggests that the ETC is responsible for the reduction of oxidizing compounds other than oxygen. Moreover, we found great diversity in the reducing activities of natural L. lactis strains originating from the dairy environment. This diversity allows selection of specific strains that can be used to modulate the redox potential of fermented dairy products to optimize their microbial and sensorial qualities.
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Koh JU, Chung HJ, Chang WY, Tanokura M, Kong KH. Discovery and Characterization of a Thermostable NADH Oxidase from Pyrococcus horikoshii OT3. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.12.2984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Jeanson S, Hilgert N, Coquillard MO, Seukpanya C, Faiveley M, Neveu P, Abraham C, Georgescu V, Fourcassié P, Beuvier E. Milk acidification by Lactococcus lactis is improved by decreasing the level of dissolved oxygen rather than decreasing redox potential in the milk prior to inoculation. Int J Food Microbiol 2009; 131:75-81. [DOI: 10.1016/j.ijfoodmicro.2008.09.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 09/22/2008] [Accepted: 09/26/2008] [Indexed: 11/30/2022]
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35
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Yang X, Ma K. Characterization of an exceedingly active NADH oxidase from the anaerobic hyperthermophilic bacterium Thermotoga maritima. J Bacteriol 2007; 189:3312-7. [PMID: 17293421 PMCID: PMC1855830 DOI: 10.1128/jb.01525-06] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An NADH oxidase from the anaerobic hyperthermophilic bacterium Thermotoga maritima was purified. The enzyme was very active in catalyzing the reduction of oxygen to hydrogen peroxide with an optimal pH value of 7 at 80 degrees C. The V(max) was 230 +/- 14 mumol/min/mg (k(cat)/K(m) = 548,000 min(-1) mM(-1)), and the K(m) values for NADH and oxygen were 42 +/- 3 and 43 +/- 4 muM, respectively. The NADH oxidase was a heterodimeric flavoprotein with two subunits with molecular masses of 54 kDa and 46 kDa. Its gene sequences were identified, and the enzyme might represent a new type of NADH oxidase in anaerobes. An NADH-dependent peroxidase with a specific activity of 0.1 U/mg was also present in the cell extract of T. maritima.
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Affiliation(s)
- Xianqin Yang
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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36
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Heux S, Cachon R, Dequin S. Cofactor engineering in Saccharomyces cerevisiae: Expression of a H2O-forming NADH oxidase and impact on redox metabolism. Metab Eng 2006; 8:303-14. [PMID: 16473032 DOI: 10.1016/j.ymben.2005.12.003] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 12/06/2005] [Accepted: 12/13/2005] [Indexed: 10/25/2022]
Abstract
The pyridine nucleotides NAD(H) and NADP(H) play major roles in the formation of by-products. To analyse how Saccharomyces cerevisiae (S. cerevisiae) metabolism during growth on glucose might be altered when intracellular NADH pool is decreased, we expressed noxE encoding a water-forming NADH oxidase from Lactococcus lactis (L. lactis) in the S. cerevisiae strain V5. During batch fermentation under controlled microaeration conditions, expression of the NADH oxidase under the control of a yeast promoter lead to large decreases in the intracellular NADH concentration (five-fold) and NADH/NAD+ ratio (six-fold). This increased NADH consumption caused a large redistribution of metabolic fluxes. The ethanol, glycerol, succinate and hydroxyglutarate yields were significantly reduced as a result of the lower NADH availability, whereas the formation of more oxidized metabolites, acetaldehyde, acetate and acetoin was favoured. The biomass yield was low and consumption of glucose, at concentration above 10%, was impaired. The metabolic redistribution in cells expressing the NADH oxidase was a consequence of the maintenance of a redox balance and of the management of acetaldehyde formation, which accumulated at toxic levels early in the process.
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Affiliation(s)
- Stéphanie Heux
- UMR Sciences pour l'Oenologie, Microbiologie, INRA, 2 place Viala, F-34060 Montpellier Cedex 1, France
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Welman AD, Maddox IS, Archer RH. Metabolism associated with raised metabolic flux to sugar nucleotide precursors of exopolysaccharides in Lactobacillus delbrueckii subsp. bulgaricus. J Ind Microbiol Biotechnol 2006; 33:391-400. [PMID: 16453122 DOI: 10.1007/s10295-005-0075-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2005] [Accepted: 12/24/2005] [Indexed: 10/25/2022]
Abstract
Exopolysaccharide (EPS) metabolism was studied in a galactose-negative strain of Lactobacillus delbrueckii subsp. bulgaricus, using two different approaches. Firstly, using both the parent strain and a chemically induced mutant with higher yield and specific productivity of EPS than the parent, comparative information was obtained relating to enzyme activities and metabolite levels associated with EPS formation when grown on lactose. Under continuous culture conditions (D = 0.10 h(-1)), the higher metabolic flux towards EPS formation in the mutant strain relative to the parent appeared to be mediated by raised levels of UDP-glucose pyrophosphorylase (UGP). Marginally raised UDP-galactose 4-epimerase (UGE) activity in the mutant strain suggested that this enzyme could also play a role in EPS overproduction. The second approach involved investigating the effect of growth rate on sugar nucleotide metabolism in the parent, as it is known that EPS production is growth-associated in this strain. UGE activity in the parent strain appeared to increase when the growth rate was elevated from 0.05 to 0.10 h(-1), and further to 0.35 h(-1), conditions that can be associated with higher levels of metabolic flux to EPS formation. Concurrent with these increments, intracellular ATP levels in the cell were raised. In both investigations glucose-6-phosphate accumulated pointing to a constriction at this branch-point, and a limitation in the flow of carbon towards fructose-6-phosphate or glucose-1-phosphate. The changes in metabolism associated with enhanced flux to EPS provide guidance as to how the yield of Lactobacillus delbrueckii subsp. bulgaricus EPS can be improved.
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Affiliation(s)
- A D Welman
- Fonterra Research Centre, Fonterra Co-operative Group Limited, Private Bag 11029, Palmerston North, New Zealand.
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38
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Jiang R, Riebel B, Bommarius A. Comparison of Alkyl Hydroperoxide Reductase (AhpR) and Water-Forming NADH Oxidase fromLactococcus lactis ATCC 19435. Adv Synth Catal 2005. [DOI: 10.1002/adsc.200505063] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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39
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Jiang R, Bommarius AS. Hydrogen peroxide-producing NADH oxidase (nox-1) from Lactococcus lactis. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.tetasy.2004.07.057] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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40
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Hoefnagel MHN, Starrenburg MJC, Martens DE, Hugenholtz J, Kleerebezem M, Van Swam II, Bongers R, Westerhoff HV, Snoep JL. Metabolic engineering of lactic acid bacteria, the combined approach: kinetic modelling, metabolic control and experimental analysis. MICROBIOLOGY (READING, ENGLAND) 2002; 148:1003-1013. [PMID: 11932446 DOI: 10.1099/00221287-148-4-1003] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Everyone who has ever tried to radically change metabolic fluxes knows that it is often harder to determine which enzymes have to be modified than it is to actually implement these changes. In the more traditional genetic engineering approaches 'bottle-necks' are pinpointed using qualitative, intuitive approaches, but the alleviation of suspected 'rate-limiting' steps has not often been successful. Here the authors demonstrate that a model of pyruvate distribution in Lactococcus lactis based on enzyme kinetics in combination with metabolic control analysis clearly indicates the key control points in the flux to acetoin and diacetyl, important flavour compounds. The model presented here (available at http://jjj.biochem.sun.ac.za/wcfs.html) showed that the enzymes with the greatest effect on this flux resided outside the acetolactate synthase branch itself. Experiments confirmed the predictions of the model, i.e. knocking out lactate dehydrogenase and overexpressing NADH oxidase increased the flux through the acetolactate synthase branch from 0 to 75% of measured product formation rates.
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Affiliation(s)
- Marcel H N Hoefnagel
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Marjo J C Starrenburg
- NIZO Food Research, PO Box 20, 6710 BA, Ede, The Netherlands3
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Dirk E Martens
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Jeroen Hugenholtz
- NIZO Food Research, PO Box 20, 6710 BA, Ede, The Netherlands3
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Michiel Kleerebezem
- NIZO Food Research, PO Box 20, 6710 BA, Ede, The Netherlands3
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Iris I Van Swam
- NIZO Food Research, PO Box 20, 6710 BA, Ede, The Netherlands3
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Roger Bongers
- NIZO Food Research, PO Box 20, 6710 BA, Ede, The Netherlands3
- Wageningen Centre for Food Sciences1 and Food and Bioprocess Engineering Group,2 Wageningen University, PO Box 8129, 6700 EV Wageningen, The Netherlands
| | - Hans V Westerhoff
- BioCentrum Amsterdam, Dept of Molecular Cell Physiology, Free University, De Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands4
| | - Jacky L Snoep
- Dept of Biochemistry, University of Stellenbosch, Private bag X1, Matieland 7602, Stellenbosch, South Africa5
- BioCentrum Amsterdam, Dept of Molecular Cell Physiology, Free University, De Boelelaan 1087, NL-1081 HV Amsterdam, The Netherlands4
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