基于甘薯渣碳源与补料策略的白色链霉菌生产ε-聚赖氨酸研究OA

ε-Poly-L-lysine(ε-PL),a natural and broad-spectrum preservative,is extensively utilized in food,cosmetic and pharma-ceutical industries.Currently,ε-PL is mainly produced through submerged fermentation by Streptomyces albulus.The carbon source glucose generally accounts for most of the ε-PL production costs.Therefore,developing cheaper and alternative carbon sources is crucial for ε-PL fermentation.In this study,sweet potato residue hydrolysate(SPRH)used as carbon sources for ε-PL production by S.albulus ZY1 was investigated.When the initial glucose concentration in the SPRH was 50 g/L,after 72 h of shake flask fermentation,the ε-PL titer achieved 1.55 g/L.In addition,compared with the M3G medium(a conventional control medium using pure glucose as the sole carbon source),the activities of glucose-6-phosphate dehydrogenase and ε-PL synthetase in the SPRH increased by 14.3％and 6.4％at 48 h,respectively.Subsequently,transcriptome analysis showed that 37 upregulated genes and 76 downregulated genes were identified.Among these,the ffs gene,which is involved in the protein translocation process mediated by the signal recognition particle(SRP),was upregu-lated.Finally,in fed-batch fermentation with a 5 L bioreactor,ε-PL titer reached 39.09 g/L with a productivity of 4.89 g/(L·d)at the end of fermentation.In summary,this study provided a reference for efficient ε-PL production using agricultural residues as economical carbon sources.