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Wang X, Chen P, Wang J, Wang Y, Miao Y, Wang X, Li Q, Zhang X, Duan J. Acetolactate Decarboxylase as an Important Regulator of Intracellular Acidification, Morphological Features, and Antagonism Properties in the Probiotic Lactobacillus reuteri. Mol Nutr Food Res 2024; 68:e2300337. [PMID: 38048544 DOI: 10.1002/mnfr.202300337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/01/2023] [Indexed: 12/06/2023]
Abstract
SCORE This study identifies the coding gene (aldB) of acetolactate decarboxylase (ALDC) as an important regulatory gene of the intracellular pH in Lactobacillus reuteri (L. reuteri), uncovering the important role of ALDC in regulating intracellular pH, morphological features, and antagonism properties in the probiotic organism L. reuteri. METHODS AND RESULTS The aldB mutant (ΔaldB) of L. reuteri is established using the homologous recombination method. Compare to the wild-type (WT) strain, the ΔaldB strain shows a smaller body size, grows more slowly, and contains more acid in the cell cytoplasm. The survival rate of the ΔaldB strain is much lower in low pH and simulated gastric fluid (SGF) than that of the WT strain, but higher in simulated intestinal fluid (SIF). The antagonism test demonstrates the ΔaldB strain can inhibit Listeria monocytogenes (L. monocytogenes) and Salmonella more effectively than the WT strain. Additionally, there is a dramatic decrease in the adhesion rate of Salmonella to Caco-2 and HT-29 cells in the presence of the ΔaldB strain compared to the WT strain. Simultaneously analyze, the auto-aggregation, co-aggregation, cell surface hydrophobicity (CSH), hemolytic, temperature, NaCl, oxidative stress, and antibiotic susceptibility of the ΔaldB strain are consistent with the features of probiotics. CONCLUSION This study highlights that the aldB gene plays a significant role in the growth and antibacterial properties of L. reuteri.
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Affiliation(s)
- Xueqing Wang
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Peng Chen
- Engineering Laboratory of Chemical Resources Utilization in South Xinjiang of Xinjiang Production and Construction Corps, Tarim University, Alar, Xinjiang, 843300, China
| | - Jing Wang
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yu Wang
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yu Miao
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xinling Wang
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Qiulei Li
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Xiaoli Zhang
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Jinyou Duan
- College of Chemistry & Pharmacy, Northwest A&F University, Yangling, Shaanxi, 712100, China
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Production of the Food Enzyme Acetolactate Decarboxylase (ALDC) from Bacillus subtilis ICA 56 Using Agro-Industrial Residues as Feedstock. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8120675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During the beer brewing process, some compounds are formed in the primary fermentation step and may affect the final quality of beer. These compounds, called off flavors, such as diacetyl, are produced during fermentation and are related to a buttery taste. The use of acetolactate decarboxylase (ALDC) in the traditional beer brewing process may significantly increase productivity since it allows for a faster decrease in the adverse flavor caused by diacetyl. However, production costs directly impact its application. For this reason, we analyzed the effect of different cultivation media on ALDC production by Bacillus subtilis ICA 56 and process economics. Different carbon and nitrogen sources, including agro-industrial residues, were evaluated. The best result was obtained using sugarcane molasses and corn steep solids (CSS), allowing a 74% reduction in ALDC production cost and an enzyme activity of 4.43 ± 0.12 U·mL−1. The enzymatic extract was then characterized, showing an optimum temperature at 40 °C and stability at different pH levels, being able to maintain more than 80% of its catalytic capacity between pH values of 3.6 and 7.0, with higher enzymatic activity at pH 6.0 (50 mM MES Buffer), reaching an ALDC activity of 5.30 ± 0.06 U·mL−1.
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Kim Y, Yoon S, Shin H, Jo M, Lee S, Kim SH. Isolation of Lactococcus lactis ssp. cremoris LRCC5306 and Optimization of Diacetyl Production Conditions for Manufacturing Sour Cream. Food Sci Anim Resour 2021; 41:373-385. [PMID: 34017948 PMCID: PMC8112315 DOI: 10.5851/kosfa.2021.e3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/26/2020] [Accepted: 01/23/2021] [Indexed: 11/06/2022] Open
Abstract
The sensory properties and flavor of sour cream are important factors that influence consumer acceptability. The present study aimed to isolate lactic acid bacteria with excellent diacetyl production ability and to optimize the fermentation conditions for sour cream manufacture. Lactococcus lactis ssp. cremoris was isolated as a lactic acid bacterium derived from raw milk. This strain showed the greatest diacetyl production among other strains and was named LRCC5306. Various culture conditions were optimized to improve the diacetyl production of LRCC5306. The highest diacetyl production was found to be at 105.04±2.06 mg/L, when 0.2% citric acid and 0.001% Fe2+ were added and cultured at 20°C for 15 h. Based on the optimal cultivation conditions, sour cream was manufactured using LRCC5306, with a viable count of 1.04×108 CFU/g and a diacetyl concentration of 106.56±1.53 mg/g. The electronic tongue system was used to compare the sensory properties of the sour cream; the fermented product exhibited sweetness and saltiness which was similar to that of an imported commercial product, but with slightly reduced bitterness and a significantly greater degree of sour taste. Therefore, our study shows that if cream is fermented using the LRCC5306, it is possible to produce sour cream with greatly improved sensory attractiveness, resulting in increased acceptance by consumers. Since this sour cream has a higher viable count of lactic acid bacteria, it is also anticipated that it will have a better probiotic effect.
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Affiliation(s)
- Yunsik Kim
- Department of Biosystems and
Biotechnology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
| | - Seokmin Yoon
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Hyejung Shin
- Department of Food Bioscience and
Technology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
| | - Miyoun Jo
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Sunmin Lee
- Food-Biotech Team, Division of Basic
Research, Lotte R&D Center, Seoul 07594,
Korea
| | - Sae-hun Kim
- Department of Food Bioscience and
Technology, College of Life Science and Biotechnology, Korea
University, Seoul 02841, Korea
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Ji F, Feng Y, Li M, Long F, Yang Y, Wang T, Wang J, Bao Y, Xue S. Structure and catalytic mechanistic insight into Enterobacter aerogenes acetolactate decarboxylase. Enzyme Microb Technol 2019; 126:9-17. [PMID: 31000168 DOI: 10.1016/j.enzmictec.2019.03.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/20/2019] [Accepted: 03/04/2019] [Indexed: 11/25/2022]
Abstract
α-Acetolactate decarboxylase (ALDC) catalyses α-acetolactate into acetoin (3-hydroxy-2-butanone, AC) and is considered to be the rate-limiting enzyme in the synthesis of 2,3-butanediol. In this work, the enzymatic activity of ALDC from Enterobacter aerogenes ALDC (E.a.-ALDC) was fully characterized with enzyme kinetics, indicating a Km of 14.83 ± 0.87 mM and a kcat of 0.81 ± 0.09 s-1. However, compared with the activities of ALDCs reported from other bacteria, the activity of E.a.-ALDC was determined to present a relatively lower value of 849.08 ± 35.21 U/mg. The enzyme showed maximum activity at pH 5.5. In addition, the activity of E.a.-ALDC was promoted by Mg2+. The crystal structure of E.a.-ALDC firstly solved by X-ray crystallography at resolution of 2.4 Å revealed a chelated zinc ion with conserved His199, His201, His212, Glu70 and Glu259. In the active center, the conservative Arg150 was particularly proven to deviate from the zinc ion of the active centre, by adopting a flexible conformational change, resulting in a weak interaction network of the enzyme and the substrate. Further in silico docking of E.a.-ALDC with two enantiomers, (R)-acetolactate and (S)-acetolactate, unaltered the interaction network of E.a.-ALDC from the apo structure, which confirmed the weakened role of Arg150 in the catalytic properties of E.a.-ALDC. Our results reveal a unique structure-function relationship of acetolactate decarboxylase and provide a fundamental basis for the enzymatic synthesis of acetoin.
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Affiliation(s)
- Fangling Ji
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China.
| | - Yanbin Feng
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, PR China
| | - Mingyang Li
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China
| | - Feida Long
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China
| | - Yongliang Yang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China
| | - Tianqi Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China
| | - Jingyun Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China
| | - Yongming Bao
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning, 116024, PR China; School of Food and Environment Science and Engineering, Dalian University of Technology, Panjin, Liaoning, 12422, PR China
| | - Song Xue
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning, 116023, PR China.
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High production of optically pure (3R)-acetoin by a newly isolated marine strain of Bacillus subtilis CGMCC 13141. Bioprocess Biosyst Eng 2018; 42:475-483. [DOI: 10.1007/s00449-018-2051-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/30/2018] [Indexed: 12/21/2022]
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Ji F, Feng Y, Li M, Yang Y, Wang T, Wang J, Bao Y, Xue S. Studies on structure-function relationships of acetolactate decarboxylase from Enterobacter cloacae. RSC Adv 2018; 8:39066-39073. [PMID: 35558320 PMCID: PMC9090609 DOI: 10.1039/c8ra07379a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/15/2018] [Indexed: 12/29/2022] Open
Abstract
Acetoin is an important bio-based platform chemical with wide applications. Among all bacterial strains, Enterobacter cloacae is a well-known acetoin producer via α-acetolactate decarboxylase (ALDC), which converts α-acetolactate into acetoin and is identified as the key enzyme in the biosynthetic pathway of acetoin. In this work, the enzyme properties of Enterobacter cloacae ALDC (E.c.-ALDC) were characterized, revealing a K m value of 12.19 mM and a k cat value of 0.96 s-1. Meanwhile, the optimum pH of E.c.-ALDC was 6.5, and the activity of E.c.-ALDC was activated by Mn2+, Ba2+, Mg2+, Zn2+ and Ca2+, while Cu2+ and Fe2+ significantly inhibited ALDC activity. More importantly, we solved and reported the first crystal structure of E.c.-ALDC at 2.4 Å resolution. The active centre consists of a zinc ion coordinated by highly conserved histidines (199, 201 and 212) and glutamates (70 and 259). However, the conserved Arg150 in E.c.-ALDC orients away from the zinc ion in the active centre of the molecule, losing contact with the zinc ion. Molecular docking of the two enantiomers of α-acetolactate, (R)-acetolactate and (S)-acetolactate allows us to further investigate the interaction networks of E.c.-ALDC with the unique conformation of Arg150. In the models, no direct contacts are observed between Arg150 and the substrates, which is unlikely to maintain the stabilization function of Arg150 in the catalytic reaction. The structure of E.c.-ALDC provides valuable information about its function, allowing a deeper understanding of the catalytic mechanism of ALDCs.
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Affiliation(s)
- Fangling Ji
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
| | - Yanbin Feng
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian Liaoning 116023 P. R. China
| | - Mingyang Li
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
| | - Yongliang Yang
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
| | - Tianqi Wang
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
| | - Jingyun Wang
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
| | - Yongming Bao
- School of Life Science and Biotechnology, Dalian University of Technology Dalian Liaoning 116024 P. R. China
- School of Food and Environment Science and Engineering, Dalian University of Technology Panjin Liaoning 12422 P. R. China
| | - Song Xue
- Marine Bioengineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian Liaoning 116023 P. R. China
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Ji F, Li M, Feng Y, Wu S, Wang T, Pu Z, Wang J, Yang Y, Xue S, Bao Y. Structural and enzymatic characterization of acetolactate decarboxylase from Bacillus subtilis. Appl Microbiol Biotechnol 2018; 102:6479-6491. [DOI: 10.1007/s00253-018-9049-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 11/25/2022]
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