Production of the siderophore lysochelin in rich media through maltose-promoted high-density growth of Lysobacter sp. 3655

Authors

Fang Zhang, Fujian Normal University
Jia Liu, Fujian Normal University
Lin Jiang, Fujian Normal University
Yongbiao Zheng, Fujian Normal University
Lingjun Yu, Fujian Normal University
Liangcheng Du, University of Nebraska - LincolnFollow

Document Type

Article

Date of this Version

6-10-2024

Citation

Zhang F, Liu J, Jiang L, Zheng Y, Yu L and Du L (2024) Production of the siderophore lysochelin in rich media through maltose-promoted high-density growth of Lysobacter sp. 3655. Front. Microbiol. 15:1433983. doi: 10.3389/fmicb.2024.1433983

Comments

Open access.

Abstract

Siderophores are produced by bacteria in iron-restricted conditions. However, we found maltose could induce the biosynthesis of the siderophore lysochelin in Lysobacter sp. 3655 in rich media that are not compatible with siderophore production. Maltose markedly promoted cell growth, with over 300% increase in cell density (OD₆₀₀) when LB medium was added with maltose (LBM). While lysochelin was not detectable when OD₆₀₀ in LBM was below 5.0, the siderophore was clearly produced when OD₆₀₀ reached 7.5 and dramatically increased when OD₆₀₀ was 15.0. Coincidently, the transcription of lysochelin biosynthesis genes was remarkably enhanced following the increase of OD₆₀₀. Conversely, the iron concentration in the cell culture dropped to 1.2μM when OD₆₀₀ reached 15.0, which was 6-fold lower than that in the starting medium. Moreover, mutants of the maltose-utilizing genes (orf2677 and orf2678) or quorum-sensing related gene orf644 significantly lowered the lysochelin yield. Transcriptomics analysis showed that the iron-utilizing/up-taking genes were up-regulated under high cell density. Accordingly, the transcription of lysochelin biosynthetic genes and the yield of lysochelin were stimulated when the iron-utilizing/up-taking genes were deleted. Finally, lysochelin biosynthesis was positively regulated by a TetR regulator (ORF3043). The lysochelin yield in orf3043 mutant decreased to 50% of that in the wild type and then restored in the complementary strain. Together, this study revealed a previously unrecognized mechanism for lysochelin biosynthetic regulation, by which the siderophore could still be massively produced in Lysobacter even grown in a rich culture medium. This finding could find new applications in large-scale production of siderophores in bacteria.