State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical, Nanjing Tech University, Nanjing, 211816, People's Republic of China.
Bioprocess Biosyst Eng. 2018 Jun;41(6):811-817. doi: 10.1007/s00449-018-1915-2. Epub 2018 Mar 2.
Industrial grade soluble corn starch was used directly and effectively as the fermentation substrate for microbial exopolysaccharides production. Bacillus subtilis mutant strain NJ308 grew with untreated starch raw material as the sole carbon source. The real-time PCR results demonstrated that up-regulated genes encoding N-acetylglucosaminyltransferase, mannosyltransferase, and N-acetylglucosamine-1-phosphate uridyltransferase were the key elements of B. subtilis mutant strain NJ308 for exopolysaccharides production from industrial grade starch. Subsequently, the culture conditions for B. subtilis NJ308 were optimized using Plackett-Burman design and central composite design methods, and the related key genes in the synthesis pathway of exopolysaccharides from the starch raw material were analyzed by real-time PCR. The maximum exopolysaccharides titration (3.41 g/L) was obtained when the initial starch concentration was 45 g/L. This corresponds to volumetric productivity values of 71.04 mg/L h.
工业级可溶性玉米淀粉可直接有效用作微生物胞外多糖生产的发酵底物。枯草芽孢杆菌突变株 NJ308 以未经处理的淀粉原料为唯一碳源生长。实时 PCR 结果表明，上调的编码 N-乙酰氨基葡萄糖基转移酶、甘露糖基转移酶和 N-乙酰氨基葡萄糖-1-磷酸尿苷转移酶的基因是枯草芽孢杆菌突变株 NJ308 利用工业级淀粉生产胞外多糖的关键因素。随后，采用 Plackett-Burman 设计和中心组合设计方法对枯草芽孢杆菌 NJ308 的培养条件进行了优化，并通过实时 PCR 分析了淀粉原料中胞外多糖合成途径的相关关键基因。当初始淀粉浓度为 45g/L 时，胞外多糖的最高滴定度（3.41g/L）。这对应于 71.04mg/L·h 的比生产率值。
