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Zhou Z, Jian D, Gong M, Zhu S, Li G, Zhang S, Zhong F, Mao J. Characterization of the key aroma compounds in aged Zhenjiang aromatic vinegar by gas chromatography-olfactometry-mass spectrometry, quantitative measurements, aroma recombination and omission experiments. Food Res Int 2020; 136:109434. [PMID: 32846543 DOI: 10.1016/j.foodres.2020.109434] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 06/07/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022]
Abstract
Zhenjiang aromatic vinegar (ZAV) is one of the most famous traditional Chinese cereal vinegars. The key aroma compounds in aged ZAV were characterized by gas chromatography-olfactometry-mass spectrometry (GC-O-MS), odor activity values (OAVs), aroma recombination and omission experiments. Sensory analysis revealed that higher odor intensity of caramel-like, buttery and overall complexity were observed for aged ZAV compared with fresh ZAV. A total of 68 compounds were quantitated, including 27 odorants with OAVs >1.0 in the aged ZAV. Sotolon was detected for the first time in Chinese cereal vinegars. Furthermore, the levels of 2,3-butanedione, 2-methylpropanal, sotolon, dimethyl trisulfide, 3-hydroxy-2-butanone, 2,4,5-trimethyloxazole and tetramethylpyrazine changed significantly during the aging process. Aroma recombination revealed that the aroma profile of the aged vinegar could be closely simulated. Omission experiments demonstrated the important contributions of seven aroma compounds to the aged ZAV aroma, including 2,3-butanedione, acetic acid, 2-methylpropanal, sotolon, 2,4,5-trimethyloxazole, 3-methylbutanoic acid and tetramethylpyrazine. This study indicates that the aging process substantially contribute to the overall aroma of ZAV.
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Affiliation(s)
- Zhilei Zhou
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Dongzhen Jian
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China; School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Min Gong
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Shenghu Zhu
- Jiangsu Hengshun Vinegar Industry Co., Ltd., Zhenjiang 212143, Jiangsu, China
| | - Guoquan Li
- Jiangsu Hengshun Vinegar Industry Co., Ltd., Zhenjiang 212143, Jiangsu, China
| | - Si Zhang
- South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, Guangdong, China
| | - Fang Zhong
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Jian Mao
- National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China; National Engineering Research Center for Huangjiu, Shaoxing 312000, Zhejiang, China.
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A high-throughput system for screening high diacetyl-producing lactic acid bacteria in fermented milk in 96-well microplates. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2020. [DOI: 10.1007/s11694-019-00321-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Dorau R, Chen L, Liu J, Jensen PR, Solem C. Efficient production of α-acetolactate by whole cell catalytic transformation of fermentation-derived pyruvate. Microb Cell Fact 2019; 18:217. [PMID: 31884954 PMCID: PMC6936138 DOI: 10.1186/s12934-019-1271-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 12/14/2019] [Indexed: 11/29/2022] Open
Abstract
Background Diacetyl provides the buttery aroma in products such as butter and margarine. It can be made via a harsh set of chemical reactions from sugarcane bagasse, however, in dairy products it is normally formed spontaneously from α-acetolactate, a compound generated by selected lactic acid bacteria in the starter culture used. Due to its bacteriostatic properties, it is difficult to achieve high levels of diacetyl by fermentation. Here we present a novel strategy for producing diacetyl based on whole-cell catalysis, which bypasses the toxic effects of diacetyl. Results By expressing a robust α-acetolactate synthase (ALS) in a metabolically optimized Lactococcus lactis strain we obtained a whole-cell biocatalyst that efficiently converted pyruvate into α-acetolactate. After process optimization, we achieved a titer for α-acetolactate of 172 ± 2 mM. Subsequently we used a two-stage production setup, where pyruvate was produced by an engineered L. lactis strain and subsequently used as the substrate for the biocatalyst. Using this approach, 122 ± 5 mM and 113 ± 3 mM α-acetolactate could be made from glucose or lactose in dairy waste, respectively. The whole-cell biocatalyst was robust and fully active in crude fermentation broth containing pyruvate. Conclusions An efficient approach for converting sugar into α-acetolactate, via pyruvate, was developed and tested successfully. Due to the anaerobic conditions used for the biotransformation, little diacetyl was generated, and this allowed for efficient biotransformation of pyruvate into α-acetolactate, with the highest titers reported to date. The use of a two-step procedure for producing α-acetolactate, where non-toxic pyruvate first is formed, and subsequently converted into α-acetolactate, also simplified the process optimization. We conclude that whole cell catalysis is suitable for converting lactose in dairy waste into α-acetolactate, which favors resource utilization.
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Affiliation(s)
- Robin Dorau
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Lin Chen
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Jianming Liu
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
| | - Christian Solem
- National Food Institute, Technical University of Denmark, 2800 Kgs., Lyngby, Denmark.
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Wang Y, Sun W, Zheng S, Zhang Y, Bao Y. Genetic engineering of Bacillus sp. and fermentation process optimizing for diacetyl production. J Biotechnol 2019; 301:2-10. [DOI: 10.1016/j.jbiotec.2019.05.308] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/25/2019] [Accepted: 05/31/2019] [Indexed: 10/26/2022]
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Generation of Flavors and Fragrances Through Biotransformation and De Novo Synthesis. FOOD BIOPROCESS TECH 2018. [DOI: 10.1007/s11947-018-2180-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Production of diacetyl by metabolically engineered Enterobacter cloacae. Sci Rep 2015; 5:9033. [PMID: 25761989 PMCID: PMC4357014 DOI: 10.1038/srep09033] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 02/11/2015] [Indexed: 11/21/2022] Open
Abstract
Diacetyl, a high value product that can be extensively used as a food ingredient, could be produced from the non-enzymatic oxidative decarboxylation of α-acetolactate during 2,3-butanediol fermentation. In this study, the 2,3-butanediol biosynthetic pathway in Enterobacter cloacae subsp. dissolvens strain SDM, a good candidate for microbial 2,3-butanediol production, was reconstructed for diacetyl production. To enhance the accumulation of the precursor of diacetyl, the α-acetolactate decarboxylase encoding gene (budA) was knocked out in strain SDM. Subsequently, the two diacetyl reductases DR-I (gdh) and DR-II (budC) encoding genes were inactivated in strain SDM individually or in combination to decrease the reduction of diacetyl. Although the engineered strain E. cloacae SDM (ΔbudAΔbudC) was found to have a good ability for diacetyl production, more α-acetolactate than diacetyl was produced simultaneously. In order to enhance the nonenzymatic oxidative decarboxylation of α-acetolactate to diacetyl, 20 mM Fe3+ was added to the fermentation broth at the optimal time. In the end, by using the metabolically engineered strain E. cloacae SDM (ΔbudAΔbudC), diacetyl at a concentration of 1.45 g/L was obtained with a high productivity (0.13 g/(L·h)). The method developed here may be a promising process for biotechnological production of diacetyl.
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Gao X, Xu N, Li S, Liu L. Metabolic engineering of Candida glabrata for diacetyl production. PLoS One 2014; 9:e89854. [PMID: 24614328 PMCID: PMC3948628 DOI: 10.1371/journal.pone.0089854] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 01/26/2014] [Indexed: 01/04/2023] Open
Abstract
In this study, Candida glabrata, an efficient pyruvate-producing strain, was metabolically engineered for the production of the food ingredient diacetyl. A diacetyl biosynthetic pathway was reconstructed based on genetic modifications and medium optimization. The former included (i) channeling carbon flux into the diacetyl biosynthetic pathway by amplification of acetolactate synthase, (ii) elimination of the branched pathway of α-acetolactate by deleting the ILV5 gene, and (iii) restriction of diacetyl degradation by deleting the BDH gene. The resultant strain showed an almost 1∶1 co-production of α-acetolactate and diacetyl (0.95 g L(-1)). Furthermore, addition of Fe3+ to the medium enhanced the conversion of α-acetolactate to diacetyl and resulted in a two-fold increase in diacetyl production (2.1 g L(-1)). In addition, increased carbon flux was further channeled into diacetyl biosynthetic pathway and a titer of 4.7 g L(-1) of diacetyl was achieved by altering the vitamin level in the flask culture. Thus, this study illustrates that C. glabrata could be tailored as an attractive platform for enhanced biosynthesis of beneficial products from pyruvate by metabolic engineering strategies.
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Affiliation(s)
- Xiang Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Nan Xu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Shubo Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China
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Gao J, Xu YY, Li FW, Ding G. Production of S-acetoin from diacetyl by Escherichia coli transformant cells that express the diacetyl reductase gene of Paenibacillus polymyxa ZJ-9. Lett Appl Microbiol 2013; 57:274-81. [PMID: 23701367 DOI: 10.1111/lam.12107] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/16/2013] [Accepted: 05/18/2013] [Indexed: 12/01/2022]
Abstract
UNLABELLED S-acetoin (S-AC) is an important four-carbon chiral compound that has unique industrial applications in the asymmetric synthesis of valuable chiral specialty chemicals. However, previous studies showed that the usually low yield and optical purity of S-AC as well as the very high substrate cost have hindered the application of this compound. In the current work, a gene encoding diacetyl reductase (DAR) from a Paenibacillus polymyxa strain ZJ-9 was cloned and expressed in Escherichia coli. Whole cells of the recombinant E. coli were used to produce S-AC from diacetyl (DA). Under optimal conditions, S-AC with high optical purity (purity >99·9%) was obtained with a yield of 13·5 ± 0·24 and 39·4 ± 0·38 g l(-1) under batch and fed-batch culture conditions, respectively. This process featured the biotransformation of DA into S-AC using whole cells of engineered E. coli. The result is a considerable increase in the yield and optical purity of S-AC, which in turn facilitated the practical application of the compound. SIGNIFICANCE AND IMPACT OF THE STUDY This study demonstrated a highly efficient new method to produce S-acetoin with higher than 99·9% optical purity from diacetyl using whole cells of engineered Escherichia coli. It will therefore decrease the production cost of S-acetoin and highlight its application in asymmetric synthesis of highly valuable chiral compounds.
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Affiliation(s)
- J Gao
- Schol of Chemical and Biological Engineering, Yancheng Institute of Technology, Yancheng, China
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Gao C, Zhang L, Xie Y, Hu C, Zhang Y, Li L, Wang Y, Ma C, Xu P. Production of (3S)-acetoin from diacetyl by using stereoselective NADPH-dependent carbonyl reductase and glucose dehydrogenase. BIORESOURCE TECHNOLOGY 2013; 137:111-5. [PMID: 23587814 DOI: 10.1016/j.biortech.2013.02.115] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 05/26/2023]
Abstract
Production of (3S)-acetoin ((3S)-AC), an important platform chemical, is desirable but difficult to perform. An NADPH-dependent carbonyl reductase (Gox0644) from Gluconobacter oxydans DSM 2003 was confirmed to have a good ability to reduce diacetyl (DA) to produce (3S)-AC. In this work, the NADPH-dependent carbonyl reductase was expressed and purified. Glucose dehydrogenase from Bacillus subtilis 168 was coupled with the NADPH-dependent carbonyl reductase to produce (3S)-AC from DA. Under the optimal conditions, 12.2 g l(-1) (3S)-AC was produced from 14.3 g l(-1) DA in 75 min. Because DA can be biotechnological produced, the two-enzymes coupling system might be a promising alternative for the (3S)-AC production.
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Affiliation(s)
- Chao Gao
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, PR China.
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Li L, Wang Y, Zhang L, Ma C, Wang A, Tao F, Xu P. Biocatalytic production of (2S,3S)-2,3-butanediol from diacetyl using whole cells of engineered Escherichia coli. BIORESOURCE TECHNOLOGY 2012; 115:111-6. [PMID: 21937220 DOI: 10.1016/j.biortech.2011.08.097] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/22/2011] [Accepted: 08/22/2011] [Indexed: 05/04/2023]
Abstract
(2S,3S)-2,3-Butanediol ((2S,3S)-2,3-BD) is a crucial chiral compound that acts as an excellent building block in asymmetric synthesis of highly valuable chiral compounds. However, the low concentration and optical purity of (2S,3S)-2,3-BD produced in previous studies limited its applications. In the present work, the gene encoding 2,3-butanediol dehydrogenase from an Enterobacter cloacae ssp. dissolvens strain SDM was cloned and expressed in Escherichia coli. Whole cells of the recombinant E. coli was used to produce (2S,3S)-2,3-BD from diacetyl. Under optimal conditions, high-optical-purity (2S,3S)-2,3-BD (purity >99%) was obtained with concentrations of 16.1 g l(-1) and 26.8 g l(-1) in batch and fed-batch conversions, respectively. Thus, the process might be a promising alternative for the production of (2S,3S)-2,3-BD.
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Affiliation(s)
- Lixiang Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, PR China
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