球形节杆菌C224分批发酵2-酮基-D-葡萄糖酸的条件优化及其动力学模型的构建

通过优化发酵条件,提高球形节杆菌C224菌株利用大米淀粉水解糖分批发酵2-酮基-D-葡萄糖酸的生产强度,并在此基础上构建其发酵动力学模型。在50 L的发酵罐上考察了通气量与葡萄糖浓度对2-酮基-D-葡萄糖酸发酵的影响,并基于Logistic方程、Luedeking-Piret方程和物料平衡计算分别构建了菌体生长、产物形成和底物消耗的动力学模型。研究结果表明,通气量低于1.5 v.v-1.m-1时,发酵生产强度明显减小,糖酸转化率有所降低;发酵培养基中的葡萄糖浓度以120.0～180.0 g/L为宜,过高或过低对生产强度和糖酸转化率均有不利影响。在适宜的发酵条件下,球形节杆菌C224菌株分批发酵生产2-酮基-D-葡萄糖酸的生产强度达6.36～6.54 g/(L.h),糖酸转化率为0.96～0.97 g/g。所构建动力学模型的计算值与实验值拟合效果良好,各项模型的相关系数R2均大于0.95,说明其能够揭示球形节杆菌C224分批发酵2-酮基-D-葡萄糖酸代谢基本特征。

Optimization of 2-keto-D-gluconic acid batch fermentation by Arthrobacter globiformis C224 and its kinetics

In the present study,the operation parameters including aeration rate and initial glucose concentration during 50-L batch fermentation were optimized to increase the 2-keto-D-gluconic acid(2KGA) productivity from rice starch hydrolysate by Arthrobacter globiformis C224.The kinetic models for describing the cell growth,2KGA production and glucose consumption were proposed by using Logistic/Luedeking-Piret equations and mass balance calculation.Results showed that the 2KGA yield decreased slightly and its productivity lowered significantly when the aeration rate was below 1.5 v·v-1·m-1.The initial glucose concentrations varying from 120.0 g/L to 180.0 g/L were optimal.Under the optimized conditions,the productivities and yields reached to 6.36～6.54 g/(L·h) and 0.96～0.97 g/g,respectively.Those proposed models could fit the predictive values well with the obtained experimental data.The determination coefficients(R2) of all models were over 0.95,which also indicated that theses models could elucidate the 2KGA metabolic characteristics of Arthrobacter globiformis C224.