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ORIGINAL RESEARCH article

Front. Microbiol.

Sec. Microbiotechnology

Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1586348

This article is part of the Research TopicRecent Insights on Thermophilic Anaerobic BacteriaView all 4 articles

Construction and Optimization of a Nisin-controlled Expression Vector using Pre-screened Strong Promoter in Streptococcus thermophilus

Provisionally accepted
Yanxin  YeYanxin Ye1RuiTing  ZhaoRuiTing Zhao2Leilei  LiLeilei Li1Zhi  LiZhi Li1Yanyan  ChenYanyan Chen1*Zhenshang  XuZhenshang Xu2*
  • 1Henan University of Urban Construction, Pingdingshan, Henan Province, China
  • 2Qilu University of Technology, Jinan, China

The final, formatted version of the article will be published soon.

Nisin-controlled gene expression (NICE) system is an efficient and promising gene expression system in Lactococcus lactis. To enhance the expression efficiency of the NICE system in S. thermophilus ATCC19258, an inducible expression vector pNZ8148-PnisA-gfp-PnisR-nisR-nisK contains the regulatory elements NisR/K and the promoter PnisR was firstly constructed using the basic plasmid pNZ8148 in this study. And the green fluorescent protein (GFP), as the reporter protein, was cloned into the downstream of PnisA in vector pNZ8148 to detect the protein expression. The resulting expression vector was electroporated into S. thermophilus, Lactobacillus plantarum, and Enterococcus faecium respectively, demonstrating that the NICE system can be used to induce protein production in various hosts of lactic acid bacteria. The optimal conditions for protein expression of recombinant strain S. thermophilus/pNZ8148-PnisA-gfp-PnisR-nisR-nisK also showed that the expression level was the highest, when the optimal induction concentration of nisin was 2500 ng/mL for 3 h after induction. Then the recombinant plasmid pNZ8148-PnisA-gfp-PnisR-nisR-nisK was optimized by using the strong promoter (P15, P18, P23, or P25) pre-screened from S. thermophilus instead of the native promoter PnisR respectively, and the results indicated that when the derived plasmid pNZ8148-PnisA-gfp-P25-nisR-nisK was electroporated into S. thermophilus, the resulting recombinant strain S. thermophilus/pNZ8148-PnisA-gfp-P25-nisR-nisK exhibited the highest expression level of heterologous green fluorescent protein.These results suggested that the improved plasmid-based nisin-controlled expression system has the potential to be used for desired protein production in S. thermophilus.

Keywords: Streptococcus thermophilus, Nisin-controlled expression system, green fluorescent protein, Strong promoter, Improvement

Received: 04 Mar 2025; Accepted: 04 Aug 2025.

Copyright: © 2025 Ye, Zhao, Li, Li, Chen and Xu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Yanyan Chen, Henan University of Urban Construction, Pingdingshan, 130012, Henan Province, China
Zhenshang Xu, Qilu University of Technology, Jinan, China

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