Efficient production of α-acetolactate by whole cell catalytic transformation of fermentation-derived pyruvate

被引:14
作者
Dorau, Robin [1 ]
Chen, Lin [1 ]
Liu, Jianming [1 ]
Jensen, Peter Ruhdal [1 ]
Solem, Christian [1 ]
机构
[1] Tech Univ Denmark, Natl Food Inst, DK-2800 Lyngby, Denmark
关键词
Biocatalysis; Lactococcus lactis; Metabolic engineering; Process engineering; Diacetyl; Lactose; LACTIS BIOVAR DIACETYLACTIS; HIGH-YIELD PRODUCTION; LACTOCOCCUS-LACTIS; ACETOIN PRODUCTION; SYNTHASE; DECARBOXYLASE;
D O I
10.1186/s12934-019-1271-1
中图分类号
Q81 [生物工程学(生物技术)]; Q93 [微生物学];
学科分类号
071005 ; 0836 ; 090102 ; 100705 ;
摘要
Background: Diacetyl provides the buttery aroma in products such as butter and margarine. It can be made via a harsh set of chemical reactions from sugarcane bagasse, however, in dairy products it is normally formed spontaneously from alpha-acetolactate, a compound generated by selected lactic acid bacteria in the starter culture used. Due to its bacteriostatic properties, it is difficult to achieve high levels of diacetyl by fermentation. Here we present a novel strategy for producing diacetyl based on whole-cell catalysis, which bypasses the toxic effects of diacetyl. Results: By expressing a robust alpha-acetolactate synthase (ALS) in a metabolically optimized Lactococcus lactis strain we obtained a whole-cell biocatalyst that efficiently converted pyruvate into alpha-acetolactate. After process optimization, we achieved a titer for alpha-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 alpha-acetolactate could be made from glucose or lactose in dairy waste, respectively. The whole-cell biocatalyst was robust and fully active in crude fermentation broth containing pyruvate. Conclusions: An efficient approach for converting sugar into alpha-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 alpha-acetolactate, with the highest titers reported to date. The use of a two-step procedure for producing alpha-acetolactate, where non-toxic pyruvate first is formed, and subsequently converted into alpha-acetolactate, also simplified the process optimization. We conclude that whole cell catalysis is suitable for converting lactose in dairy waste into alpha-acetolactate, which favors resource utilization.
引用
收藏
页数:11
相关论文
共 36 条
[31]   STUDY OF THE CITRATE METABOLISM OF LACTOCOCCUS-LACTIS SUBSP LACTIS BIOVAR DIACETYLACTIS BY MEANS OF C-13 NUCLEAR-MAGNETIC-RESONANCE [J].
VERHUE, WM ;
TJAN, FSB .
APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 1991, 57 (11) :3371-3377
[32]  
Verhue WMM, 1991, European Patent Application, P1, Patent No. [EP0483888A2, 0483888]
[33]  
WESTERFELD WW, 1945, J BIOL CHEM, V161, P495
[34]  
Zeitsch KJ., 2000, SUGAR SERIES, P120, DOI DOI 10.1016/S0167-7675(00)80016-0
[35]   Optimization and mechanism of diacetyl accumulation by Enterobacter aerogenes mutant UV-3 [J].
Zhao, Ling ;
Bao, Yongming ;
Wang, Jingyun ;
Liu, Boshi ;
An, Lijia .
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY, 2009, 25 (01) :57-64
[36]   Isolation of strong constitutive promoters from Lactococcus lactis subsp lactis N8 [J].
Zhu, Duolong ;
Liu, Fulu ;
Xu, Haijin ;
Bai, Yanling ;
Zhang, Xiuming ;
Saris, Per Erik Joakim ;
Qiao, Mingqiang .
FEMS MICROBIOLOGY LETTERS, 2015, 362 (16)