摘要
利用组合优化方法,探讨了铵盐和硝酸盐对枯草芽孢杆菌生长和补料分批发酵核黄素的影响。结果表明铵盐可促进菌体生长,抑制核黄素积累;硝酸盐可以提高核黄素的产量,抑制菌体生长;而将铵盐和硝酸盐以物质的量之比为1∶8混合使用时既有利于菌体生长又可以提高产物产量,相比单一利用硫酸铵时产量提高了30%,达到812 IU/mL;在补料分批发酵过程中,发酵后期采用NaOH调节pH,并严格控制铵离子的浓度低于10 mmol/L,相比对照组核黄素产量提高10%,达到5292 IU/mL。
Riboflavin plays a crucial role in metabolic pathway.Commercial riboflavin has been widely applied in a variety of different industries,such as,pharmaceuticals,cosmetics,human and animal nutrition etc.Recently,riboflavin product is mainly derived from biological process in industrial production.However,the focus of research has shifted to molecular modification of production strain genes,where very few attention is paid to the analysis of metabolic flux regulation during metabolism,with nitrogen regulation in particular.This work is aimed to explore how the interaction of inorganic nitrogen sources affects the riboflavin yield and cell density,and how the ammonium ion concentration influences the whole process in fed-batch culture.The results show that ammonium is effective in promoting the biomass but exerts an inhibitory effect on the yield.On the contrary,nitrate is beneficial to improve the output of riboflavin but has some adverse effect on biomass.In this work,ammonium and nitrate were employed with mole ratio 1∶8.The riboflavin yield was observed to reach 812 IU/mL,a 30%increase as compared to that with only use of ammonium under the identical condition.In fed-batch culture,ammonia is frequently involved in the regulation of pH to ensure nitrogen supply.Nevertheless,a careful control over its concentration is required.In 7 L bioreactor,glucose concentration was in the range of 5—10 g/L and the concentration of ammonium was controlled to below 10 mmol/L in the late fermentation.As a result,DCW was 74.5 g/L and the riboflavin yield was increased to 5292 IU/mL,which was 10%higher than the control.
作者
尉文
张梦雪
王学东
WEI Wen;ZHANG Mengxue;WANG Xuedong(State Key Laboratory of Bioreactor Engineering,East China University of Science and Technology,Shanghai 200237,China)
出处
《华东理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2020年第4期543-548,共6页
Journal of East China University of Science and Technology
关键词
核黄素
枯草芽孢杆菌
无机氮源
补料分批发酵
riboflavin
Bacillus subtilis
inorganic nitrogen source
fed-batch culture
