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Li Y, Luo L, Wang W, Hong B, Ma Y, Wang J. Characterization of a cell wall hydrolase with high activity against vegetative cells, spores and biofilm of Bacillus cereus. Int J Food Microbiol 2024; 414:110617. [PMID: 38335884 DOI: 10.1016/j.ijfoodmicro.2024.110617] [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: 08/08/2023] [Revised: 12/17/2023] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Bacillus cereus is a prevalent foodborne pathogen that induces food poisoning symptoms such as vomiting and diarrhea. Its capacity to form spores and biofilm enables it to withstand disinfectants and antimicrobials, leading to persistent contamination during food processing. Consequently, it is necessary to develop novel and efficient antimicrobial agents to control B. cereus, its spores, and biofilms. Peptidoglycan hydrolases have emerged as a promising and eco-friendly alternative owing to their specific lytic activity against pathogenic bacteria. Here, we identified and characterized a Lysozyme-like cell wall hydrolase Lys14579, from the genome of B. cereus ATCC 14579. Recombinant Lys14579 specifically lysed B. cereus without affecting other bacteria. Lys14579 exhibited strong lytic activity against B. cereus, effectively lysing B. cereus cell within 20 min at low concentration (10 μg/mL). It also inhibited the germination of B. cereus spores and prevented biofilm formation at 12.5 μg/mL. Moreover, Lys14579 displayed good antimicrobial stability with negligible hemolysis in mouse red blood cells and no cytotoxicity against RAW264.7 cells. Notably, Lys14579 effectively inhibited B. cereus in boiled rice and minced meat in a dose-dependent manner. Furthermore, bioinformatics analysis and point mutagenesis experiments revealed that Glu-47 was the catalytic site, and Asp-57, Gln-60, Ser-61 and Glu-63 were active-site residues related with the cell wall lytic activity. Taken together, Lys14579 could be a promising biocontrol agent against vegetative cells, spores, and biofilm of B. cereus in food industry.
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Affiliation(s)
- Yanmei Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Lun Luo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Wenhai Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Bin Hong
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou 510006, China
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou 510006, China.
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Phetcharat T, Dawkrajai P, Chitov T, Mhuantong W, Champreda V, Bovonsombut S. Biosurfactant-Producing Capability and Prediction of Functional Genes Potentially Beneficial to Microbial Enhanced Oil Recovery in Indigenous Bacterial Communities of an Onshore Oil Reservoir. Curr Microbiol 2019; 76:382-391. [PMID: 30734843 DOI: 10.1007/s00284-019-01641-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 01/28/2019] [Indexed: 11/25/2022]
Abstract
Microbial enhanced oil recovery (MEOR) is a bio-based technology with economic and environmental benefits. The success of MEOR depends greatly on the types and characteristics of indigenous microbes. The aim of this study was to evaluate the feasibility of applying MEOR at Mae Soon Reservoir, an onshore oil reservoir experiencing a decline in its production rate. We investigated the capability of the reservoir's bacteria to produce biosurfactants, and evaluated the potentials of uncultured indigenous bacteria to support MEOR by means of prediction of MEOR-related functional genes, based on a set of metagenomic 16s rRNA gene data. The biosurfactant-producing bacteria isolated from the oil-bearing sandstones from the reservoir belonged to one species: Bacillus licheniformis, with one having the ability to decrease surface tension from 72 to 32 mN/m. Gene sequences responsible for biosurfactant (licA3), lipase (lipP1) and catechol 2,3-dioxygenase (C23O) were detected in these isolates. The latter two, and other genes encoding MEOR-related functional proteins such as enoyl-CoA hydratase and alkane 1-monooxygenase, were predicted in the bacterial communities residing the reservoir's sandstones. Exposure of these sandstones to nutrients, consisting of KNO3 and NaH2PO4, resulted in an increase in the proportions of some predicted functional genes. These results indicated the potentials of MEOR application at Mae Soon site. Using the approaches demonstrated in this study would also assist evaluation of the feasibility of applying MEOR in oil reservoirs, which may be enhanced by an appropriate nutrient treatment.
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Affiliation(s)
- Thanachai Phetcharat
- Interdisciplinary Program in Biotechnology, Graduate School, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Pinan Dawkrajai
- Defence Energy Department, Northern Petroleum Development Center, Fang, Chiang Mai, 50110, Thailand
| | - Thararat Chitov
- Division of Microbiology, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.,Environmental Science Research Center (ESRC), Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Wuttichai Mhuantong
- Enzyme Technology Laboratory, The National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathum Thani, 12120, Thailand
| | - Verawat Champreda
- Enzyme Technology Laboratory, The National Center for Genetic Engineering and Biotechnology (BIOTEC), Thailand Science Park, Pathum Thani, 12120, Thailand
| | - Sakunnee Bovonsombut
- Division of Microbiology, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand. .,Environmental Science Research Center (ESRC), Chiang Mai University, Chiang Mai, 50200, Thailand. .,Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.
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