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Liu J, Zhang X, Liu G, Zhao G, Fang X, Song X. A Cumulative Effect by Multiple-Gene Knockout Strategy Leads to a Significant Increase in the Production of Sophorolipids in Starmerella Bombicola CGMCC 1576. Front Bioeng Biotechnol 2022; 10:818445. [PMID: 35356780 PMCID: PMC8959766 DOI: 10.3389/fbioe.2022.818445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
Sophorolipids (SLs), an important biosurfactant produced by S. bombicola, were one of the most potential substitutes for chemical surfactants. Few reports on the transcriptional regulation of SLs synthesis and the engineered strains with high-yield SLs were available. In this study, a Rim9-like protein (Rlp) and three transcription factors (ztf1, leu3, gcl) were mined and analyzed, and a progressive enhancement of SLs production was achieved through cumulative knockouts of three genes. The sophorolipid production of ΔrlpΔleu3Δztf1 reached 97.44 g/L, increased by 50.51% than that of the wild-type strain. Compared with the wild-type strain, the flow of glucose to SLs synthesis pathways was increased, and the synthesis of branched-chain amino acids was reduced in ΔrlpΔleu3Δztf1. The amount of UDP-glucose, the substrate for two glycosyltransferases, also increased, and the expression level of the key genes sble and UGPase for SLs synthesis increased by 2.2 times, respectively. The multiple-gene knockout strategy was proved to be highly effective to construct the engineered strain with high-yield SLs production, and this strain was a superior strain for industrial fermentation of SLs and reduced SLs production costs.
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Affiliation(s)
- Jun Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xinyu Zhang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guoqin Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xiaoran Fang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Xin Song
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
- National Glycoengineering Research Center, Shandong University, Qingdao, China
- *Correspondence: Xin Song,
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