Efficient production of α-acetolactate by whole cell catalytic transformation of fermentation-derived pyruvate
Tóm tắt
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. 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. 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.
Tài liệu tham khảo
Clark S, Winter CK. Diacetyl in foods: a review of safety and sensory characteristics. Compr Rev Food Sci Food Saf. 2015;14(5):634–43. https://doi.org/10.1111/1541-4337.12150.
Wijaya I, Rankin SA. Diacetyl levels and volatile profiles of commercial starter distillates and selected dairy foods. J Dairy Sci. 2012;95(3):1128–39. https://doi.org/10.3168/jds.2011-4834.
Zeitsch KJ. 16. Diacetyl and 2,3-pentanedione. In: Zeitsch KJ, editor. Sugar Series. 2000. p. 120–49. https://doi.org/10.1016/s0167-7675(00)80016-0.
de Man JC. The formation of diacetyl and acetoin from α-acetolactic acid. Recl des Trav Chim des Pays-Bas. 1959;78(7):480–6. https://doi.org/10.1002/recl.19590780703.
de Medina Figueroa R, Oliver G, de Benito Cárdenas IL. Influence of temperature on flavour compound production from citrate by Lactobacillus rhamnosus ATCC 7469. Microbiol Res. 2001;155(4):257–62. https://doi.org/10.1016/s0944-5013(01)80002-1.
Branen AL, Keenan TW. Diacetyl and acetoin production by Lactobacillus casei. Appl Microbiol. 1971;22(4):517–21.
Laëtitia G, Pascal D, Yann D. The citrate metabolism in homo- and heterofermentative LAB: a selective means of becoming dominant over other microorganisms in complex ecosystems. Food Nutr Sci. 2014;5(10):953–69. https://doi.org/10.4236/fns.2014.510106.
Starrenburg MJC, Hugenholtz J. Citrate fermentation by Lactococcus and Leuconostoc spp. Appl Environ Microbiol. 1991;57(12):3535–40.
Verhue WM, Tjan FSB. Study of the citrate metabolism of Lactococcus lactis subsp. lactis biovar diacetylactis by means of 13c nuclear magnetic resonance. Appl Environ Microbiol. 1991;57(11):3371–7.
Jordan KN, Cogan TM. Production of acetolactate by Streptococcus diacetylactis and Leuconostoc spp. J Dairy Res. 1988;55(2):227–38. https://doi.org/10.1017/S0022029900026054.
Ronfags E, Stien G, Germain P, Marc I. Kinetic study of the chemical reactivity of α-acetolactate as a function of pH in water, and in fresh and fermented culture media used for Lactococcus lactis spp. lactis bv. diacetylactis. Biotechnol Lett. 1996;18(7):747–52.
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. https://doi.org/10.1016/j.ymben.2016.02.008.
Seitz EW, Elliker P, Day EA, Sandine W. Studies on factors affecting diacetyl production by Streptococcus diacetylactis. J Dairy Sci. 1961;44(6):1159.
Hugenholtz J, Kleerebezem M, Starrenburg M, Delcour J, De Vos W, Hols P. Lactococcus lactis as a cell factory for high-level diacetyl production. Appl Environ Microbiol. 2000;66(9):4112–4. https://doi.org/10.1128/AEM.66.9.4112-4114.2000.
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. https://doi.org/10.1371/journal.pone.0036296.
Goupil N, Corthier G, Ehrlich SD, Renault P. Imbalance of leucine flux in Lactococcus lactis and its use for the isolation of diacetyl-overproducing strains. Appl Environ Microbiol. 1996;62(7):2636–40.
Aymes F, Monnet C, Corrieu G. Effect of α-acetolactate decarboxylase inactivation on α-acetolactate and diacetyl production by Lactococcus lactis subsp. lactis biovar diacetylactis. J Biosci Bioeng. 1999;87:87–92.
Monnet C, Aymes F, Corrieu G. Diacetyl and α-acetolactate overproduction by Lactococcus lactis subsp. lactis biovar diacetylactis mutants that are deficient in α-acetolactate decarboxylase and have a low lactate dehydrogenase activity. Appl Environ Microbiol. 2000;66(12):5518–20. https://doi.org/10.1128/aem.66.12.5518-5520.2000.
Monnet C, Schmitt P, Divies C. Development and use of a screening procedure for production of α-acetolactate by Lactococcus lactis subsp. lactis biovar diacetylactis strains. Appl Environ Microbiol. 1997;63(2):793–5.
Jay JM. Antimicrobial properties of diacetyl. Appl Environ Microbiol. 1982;44(3):525–32.
Verhue WMM, Tjan SB, Verrips CT, van Schie BJ. Process for preparing an aroma product containing α-acetolactic acid. European Patent Application; EP0483888A2, 1991. p. 1–14.
Marugg JD, Toonen MY, Verhue WMM, Verrips CT. Process for the preparation of α-acetolactic acid. European Patent Application; EP0500188A2, 1992. p. 1–23.
Liu J, Wang Z, Kandasamy V, Lee SY, Solem C, Jensen PR. Harnessing the respiration machinery for high-yield production of chemicals in metabolically engineered Lactococcus lactis. Metab Eng. 2017;44:22–9. https://doi.org/10.1016/j.ymben.2017.09.001.
De Felipe FL, Starrenburg M, Hugenholtz J. The role of NADH-oxidation in acetoin and diacetyl production from glucose in Lactococcus lactis subsp. lactis MG1363. FEMS Microbiol Lett. 1997;156:15–9. https://doi.org/10.1016/s0378-1097(97)00394-7.
Huo Y, Zhan Y, Wang Q, Li S, Yang S, Nomura CT, Wang C, Chen S. Acetolactate synthase (AlsS) in Bacillus licheniformis WX-02: enzymatic properties and efficient functions for acetoin/butanediol and l-valine biosynthesis. Bioprocess Biosyst Eng. 2018;41(1):87–96. https://doi.org/10.1007/s00449-017-1847-2.
Lee SC, Kim J, La IJ, Kim SK, Yoon MY. Characterization of recombinant FAD-independent catabolic acetolactate synthase from Enterococcus faecalis V583. Enzyme Microb Technol. 2013;52(1):54–9. https://doi.org/10.1016/j.enzmictec.2012.10.006.
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(1):57–64. https://doi.org/10.1007/s11274-008-9862-8.
Somkuti GA, Dominiecki ME, Steinberg DH. Permeabilization of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus with Ethanol. Curr Microbiol. 1998;36(4):202–6. https://doi.org/10.1007/s002849900294.
Shin KC, Sim DH, Seo MJ, Oh DK. Increased production of food-grade d-tagatose from d-galactose by permeabilized and immobilized cells of Corynebacterium glutamicum, a GRAS host, expressing d-galactose isomerase from Geobacillus thermodenitrificans. J Agric Food Chem. 2016;64(43):8146–53. https://doi.org/10.1021/acs.jafc.6b03588.
Gasson MJ. Plasmid complements of Streptococcus lactis NCDO 712 and other lactic streptococci after protoplast-induced curing. J Bacteriol. 1983;154(1):1–9.
Solem C, Defoor E, Jensen PR, Martinussen J. Plasmid pCS1966, a new selection/counterselection tool for lactic acid bacterium strain construction based on the oroP gene, encoding an orotate transporter from Lactococcus lactis. Appl Environ Microbiol. 2008;74(15):4772–5. https://doi.org/10.1128/AEM.00134-08.
Solem C, Dehli T, Jensen PR. Rewiring Lactococcus lactis for ethanol production. Appl Environ Microbiol. 2013;79(8):2512–8. https://doi.org/10.1128/AEM.03623-12.
Zhu D, Liu F, Xu H, Bai Y, Zhang X, Saris PEJ, Qiao M. Isolation of strong constitutive promoters from Lactococcus lactis subsp. lactis N8. FEMS Microbiol Lett. 2015;362(16):1–6. https://doi.org/10.1093/femsle/fnv107.
Benson KH, Godon JJ, Renault P, Griffin HG, Gasson MJ. Effect of ilvBN-encoded α-acetolactate synthase expression on diacetyl production in Lactococcus lactis. Appl Microbiol Biotechnol. 1996;45(1–2):107–11. https://doi.org/10.1007/s002530050656.
Nguyen DMN, Lipscomb GL, Schut GJ, Vaccaro BJ, Basen M, Kelly RM, Adams MWW. Temperature-dependent acetoin production by Pyrococcus furiosus is catalyzed by a biosynthetic acetolactate synthase and its deletion improves ethanol production. Metab Eng. 2016;34:71–9. https://doi.org/10.1016/j.ymben.2015.12.006.
Westerfeldt WW. A colorimetric determination of blood acetoin. J Biol Chem. 1945;161:495–502.