Enhanced Production of L(+)-lactic Acid by floc-form Culture of Rhizopus oryzae

本研究是利用絲狀形態的米根微以逹到最適生産L型乳酸的目的。用5公升的醱酵本槽生産乳酸，醱酵過程中，補充硫銨，使培養基中的氨濃度維持在0.1g/L以上，以防止菌絲凝集，用碳鈣控制pH值在4.3-4.5，乳酸的生産可逹到最適化。反之，若不補充硫銨，則菌絲凝集成塊狀，造成乳酸産量大幅降低。在起始批次醱酵，使用125g/L的葡萄糖當作基質，可得到乳酸最終濃度109g/L，産率（乳酸對消耗的葡萄糖的重量比）0.87，生産速率2.73g/L-h。重複批次醱酵，前四槽平均得到乳酸最終濃度113g/L，轉換率0.90，生産速率4.03g/L-h。

關鍵字

無資料

並列摘要

A process to optimize L-lactic acid production from glucose by Rhizopus oryzae, based on sustaining floc morphology throughout the fermentation process, is herein performed. During the fermentation, supplementary ammonium sulfate was added intermittently to maintain the ammonia level of the culture medium always higher than 0.1g/L. With replenish of nitrogen source, mycelia floes did not aggregate, and the lactic acid production was optimized upon the fermentation being controlled at pH 4.3-4.5 by adding calcium carbonate slurry. In contrast, without supplementary addition of nitrogen source, mycelial clumps formed, resulting in a poor production of lactic acid. In the initial batch fermentation process, the final concentration of lactic acid produced was 109g/L, with a yield (g lactic acid/g glucose consumed) of 0.87 and a productivity of 2.73g/L h, using 125g/L of glucose as substrate. For the first four cycles of repeated-batch fermentation, the average final concentration, the productivity and the yield of lactic acid were 113g/L, 4.03g/L h and 0.90, respectively.

並列關鍵字

Fermentation ； L-Lactic acid ； Mycelial floc ； Rhizopus oryzae

國際替代計量

Enhanced Production of L(+)-lactic Acid by floc-form Culture of Rhizopus oryzae

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