Liu Jiaheng, Huang Rongrong, Song Qianqian, Xiong Hui, Ma Juan, Xia Rui, Qiao Jianjun
Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.
Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin, China.
Front Bioeng Biotechnol. 2021 Feb 5;9:612105. doi: 10.3389/fbioe.2021.612105. eCollection 2021.
Nisin produced by certain strains is commercially used in meat and dairy industries because of its effective antibacterial activity and food safety characteristics. It has been proved that the antibacterial activity could be enhanced when combined with other antimicrobial agents. In this study, we demonstrated that nisin and 3-phenyllactic acid (PLA) in combination displayed excellent combinational antibacterial activity against foodborne pathogens including and . The potential application in food preservation was further verified microbial analysis during the storage of meat and milk, and determination of strawberry rot rate. Scanning electron microscopy observation indicated a distinct mode of PLA with nisin, which may target at the dividing cell, contributing to their combinational antibacterial effect of nisin and PLA. Considering the positive results, a nisin-PLA co-producing strain was constructed based on the food-grade strain F44, a nisin Z producer. By the knockout of two L-lactate dehydrogenase (LDH) and overexpression of D-LDH , the yield of PLA was significantly increased 1.77-fold in comparison with the wild type. Anti-bacterial assays demonstrated that the fermentation product of the recombinant strain performed highly effective antibacterial activity. These results provided a promising prospect for the nisin-PLA co-expressing in food preservation on account of its considerable antibacterial activity and cost-effective performance.
某些菌株产生的乳链菌肽因其有效的抗菌活性和食品安全特性而在肉类和乳制品行业中得到商业应用。已经证明，与其他抗菌剂联合使用时，其抗菌活性可以增强。在本研究中，我们证明乳链菌肽和3-苯乳酸（PLA）联合使用对包括[具体菌名缺失]和[具体菌名缺失]在内的食源性病原体具有优异的联合抗菌活性。通过对肉类和牛奶储存期间的微生物分析以及草莓腐烂率的测定，进一步验证了其在食品保鲜中的潜在应用。扫描电子显微镜观察表明PLA与乳链菌肽具有不同的作用方式，可能作用于正在分裂的细胞，从而产生乳链菌肽和PLA的联合抗菌效果。鉴于这些积极结果，基于食品级菌株F44（一种乳链菌肽Z产生菌）构建了一株乳链菌肽-PLA共生产菌株。通过敲除两个L-乳酸脱氢酶（LDH）并过表达D-LDH，与野生型相比，PLA的产量显著提高了1.77倍。抗菌试验表明，重组菌株的发酵产物具有高效的抗菌活性。这些结果因其可观的抗菌活性和成本效益，为乳链菌肽-PLA共表达在食品保鲜中的应用提供了广阔前景。
