Fed‐batch fermentation strategy for efficient welan gum production by Sphingomonas sp. FM01

Abstract BACKGROUND As a novel type of extracellular polysaccharide produced by Sphingomonas sp., welan gum has been widely applied in various fields because of its excellent properties. The study has improved the fermentation process. Results The initial sucrose concentration, temperature and stirring speed were set to 20 g L −1 , 33 °C and 400 rpm, respectively, and 13.3 g L −1 sucrose was added at 24, 40 and 56 h. The temperature and stirring speed were then set at 28 °C and 600 rpm from 24 to 48 h and 28 °C and 600 rpm from 48 to 72 h, respectively. As a result, welan gum production, dry cell weight, sucrose conversion rate and viscosity were correspondingly increased to 38.60 g L −1 , 5.47 g L −1 , 0.64 g g −1 and 3779 mPa·s, respectively. In addition, the mechanism by which fermentation strategy promotes welan gum synthesis was investigated by transcriptome analysis. CONCLUSION Improving respiration and ATP supply, reducing unnecessary protein synthesis, and alleviating competition between cell growth and welan gum synthesis contribute to promoting the fermentation performance of Sphingomonas sp., thus providing a practical strategy for efficient welan gum production. © 2024 Society of Chemical Industry.