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A plasmid-free Zymomonas mobilis mutant strain reducing reactive oxygen species for efficient bioethanol production using industrial effluent of xylose mother liquor

Authors :
Binan Geng
Shuyi Liu
Yunhao Chen
Yalun Wu
Yi Wang
Xuan Zhou
Han Li
Mian Li
Shihui Yang
Source :
Frontiers in Bioengineering and Biotechnology, Vol 10 (2022)
Publication Year :
2022
Publisher :
Frontiers Media S.A., 2022.

Abstract

Genome minimization is an effective way for industrial chassis development. In this study, Zymomonas mobilis ZMNP, a plasmid-free mutant strain of Z. mobilis ZM4 with four native plasmids deleted, was constructed using native type I-F CRISPR-Cas system. Cell growth of ZMNP under different temperatures and industrial effluent of xylose mother liquor were examined to investigate the impact of native plasmid removal. Despite ZMNP grew similarly as ZM4 under different temperatures, ZMNP had better xylose mother liquor utilization than ZM4. In addition, genomic, transcriptomic, and proteomic analyses were applied to unravel the molecular changes between ZM4 and ZMNP. Whole-genome resequencing result indicated that an S267P mutation in the C-terminal of OxyR, a peroxide-sensing transcriptional regulator, probably alters the transcription initiation of antioxidant genes for stress responses. Transcriptomic and proteomic studies illustrated that the reason that ZMNP utilized the toxic xylose mother liquor better than ZM4 was probably due to the upregulation of genes in ZMNP involving in stress responses as well as cysteine biosynthesis to accelerate the intracellular ROS detoxification and nucleic acid damage repair. This was further confirmed by lower ROS levels in ZMNP compared to ZM4 in different media supplemented with furfural or ethanol. The upregulation of stress response genes due to the OxyR mutation to accelerate ROS detoxification and DNA/RNA repair not only illustrates the underlying mechanism of the robustness of ZMNP in the toxic xylose mother liquor, but also provides an idea for the rational design of synthetic inhibitor-tolerant microorganisms for economic lignocellulosic biochemical production.

Details

Language :
English
ISSN :
22964185
Volume :
10
Database :
Directory of Open Access Journals
Journal :
Frontiers in Bioengineering and Biotechnology
Publication Type :
Academic Journal
Accession number :
edsdoj.219fb87d866e4810b6ea3e5898db4fea
Document Type :
article
Full Text :
https://doi.org/10.3389/fbioe.2022.1110513