Abstract In this study, focusing on efficiently producing butyric acid and utilizing semi-solid waste Pichia pastoris, a novel butyric acid fermentation strategy was developed by using 80 g/L corn as the base medium and the pretreated waste yeast suspension (250−400 g/L) as the nitrogen sources. The suspension was added into broth with a volumetric ratio of 1:4 at ∼20 h, followed by consecutively feeding concentrated glucose solution in 7 L anaerobic bioreactor. With this strategy, butyrate concentration/yield was raised to high levels of 45.0 g/L and 0.40. This strategy could effectively utilize amino acids originated from waste yeast suspension to increase Clostridium tyrobutyricum growth rate/concentration; enhance NADH dependent butyrate synthesis rate under enriched SO42− environment. As a result, butyrate fermentation performance was improved in an indirect way and recirculating bio-waste to replace expensive organic nitrogen sources was realized.

中文翻译：

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废毕赤酵母的再循环利用作为提高丁酸产量的有效氮源

摘要 本研究以高效生产丁酸和利用半固态废弃毕赤酵母为核心，以 80 g/L 玉米为基础培养基，采用预处理的废弃酵母悬浮液（250~400 g /L) 作为氮源。在约 20 小时将悬浮液以 1:4 的体积比加入肉汤中，然后连续加入 7 L 厌氧生物反应器中的浓缩葡萄糖溶液。通过这种策略，丁酸盐浓度/产量提高到 45.0 g/L 和 0.40 的高水平。该策略可以有效利用来自废酵母悬浮液的氨基酸来提高酪丁酸梭菌的生长速率/浓度；在富 SO42− 环境下提高 NADH 依赖的丁酸盐合成速率。因此，