耐氨米根霉的分批补料发酵及发酵动力学初探

以氨水为中和剂,替代CaCO3,对耐氨米根霉R.oryzaeJS-N0-2-02进行15L自动发酵罐的分批和分批补料发酵及其发酵动力学的初步研究,结果表明,降低起始糖浓度,产酸期补糖可明显提高菌体L-乳酸比生产速率和耗糖产酸能力,提高L-乳酸产量和纯度,降低残糖。在发酵起始时添加1 g/L CaCO3能进一步提高补糖发酵的L-乳酸比生产速率,增强发酵后期菌体耗糖产酸能力,从而进一步提高L-乳酸产量和纯度,降低残糖。发酵结果:起始糖浓度为120 g/L,25h时补糖使最终发酵总糖浓度达137 g/L,发酵培养60 h,L-乳酸产量可达101.8 g/L,纯度97.3%,菌体耗糖转化率76%,比生产速率0.27 g/g.h,残糖降至3 g/L。

Study on the Fed-batch Fermentation and Fermentation Kinetics of Ammonia Resistant Strain Rhizopus oryzae

With ammonia water as nertralizer,L-lactic acid batch and fed-batch fermentation by ammonia resistant mutant Rhizopus oryzae JS-N02-02 were conducted in a 15L fermentor.The kinetics of growth and L-lactic acid production were also studied.Compared with batch fermentation,the results showed that with lower initial corn hydrolysate concentration and feeding glucose at L-lactic acid-producing period,could not only increase the L-lactic acid specific productivity,specific glucose consuming rate and glucose-acid conversion rate,but also increase the yield of L-lactic acid and its purity.It is also seen that the glucose residual was lower.When 1 g/L CaCO_3 was added at the initial medial,the L-lactic acid specific productivity of glucose-feeding fermentation could be remarkably increased,and the capabily of the strain to conver glucose to L-lactic acid was improved at the later period of fermentation.Therefore,the yield of L-lactic acid and its purity could be further increased and the glucose residual could be further lowed.When the initial glucose concentration was 120 g/L and the total glucose concentration was controlled at 137 g/L by glucose feeding after 25h,the results showed that: the yield of L-lactic acid was 101.8 g/L,the purity of L-lactic acid was 97.3%,glucose-acid conversion rate was 76%,specific productivity was 0.27g/(g.h),and the residual glucose was 3 g/L.