Biotechnology Bulletin ›› 2025, Vol. 41 ›› Issue (1): 347-356.doi: 10.13560/j.cnki.biotech.bull.1985.2024-0675

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Exploration of Regulatory Elements for Hyaluronic Acid Molecular Weight in Streptococcus zooepidemicus via Transcriptome Analysis

PEI Xu-juan(), DI Jing-yi, LIU Hao, GAO Wei-xia()   

  1. Key Laboratory of Industrial Fermentation Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457
  • Received:2024-07-15 Online:2025-01-26 Published:2025-01-22
  • Contact: GAO Wei-xia E-mail:13652151929@163.com;gaoweixia@tust.edu.cn

Abstract:

【Objective】The objective of this study is to explore the influencing elements of hyaluronic acid(HA)molecular weight, and to construct Streptococcus zooepidemicus mutants that synthesize HA with different molecular weights.【Method】When Streptococcus zooepidemicus S12 was cultured using different carbon sources to produce HA, it was found that the molecular weight of HA fermented by 10 g/Lfructose as the carbon source was 1.48×106 Da, which was 29.52% lower than that of the original fermentation medium(50 g/L sucrose as the carbon source, 2.10×106 Da). Subsequently, transcriptomic sequencing of S12 fermentation broth with 50 g/L sucrose and 10 g/L fructose as carbon sources showed that the transcription levels of the two key genes of arginine deiminase pathway, arcA(encoding arginine deiminase)and argF(encoding ornithine carbamyltransferase), increased by 16.29 and 11.27 times, respectively, in addition to the fructose metabolism-related genes. In order to explore the effects of these two genes on HA synthesis, the genes arcA and argF were knocked out or overexpressed in S12, respectively.【Result】The HA molecular weight of arcA overexpressing strains was 2.96×106 Da in CDM medium, which was 50.25% higher than that of S12(1.97×106 Da), and the molecular weight of HA in the other three mutant strains did not show conspicuous changes. Further RT-qPCR showed that the transcription level of glnA, the synthase-encoding gene of glutamine(amino donor in HA synthesis), was up-regulated by 2.0 times in arcA overexpressing strain, which may be one of the reasons for the increase of the HA molecular weight.【Conclusion】Two genes related to arginine metabolism were found to regulate the molecular weight of HA, which provides new targets for other strains to control the molecular weight of HA.

Key words: Streptococcus zooepidemicus, hyaluronic acid, transcriptome, molecular weight, arginine metabolism