容积负荷变化模式对嗜盐混合菌发酵乙酸合成PHB的影响

摘要

Polyhydroxybutyrate (PHB) production by halophilic mixed consortia draws a lot of attention because of its great advantages, such as no sterilization, extraction convenience and high production. In this study, halophilic mixed microbial cultures were used to investigate the influence of adjusting modes of the organic loading rate on PHB production. Two adjusting modes were applied including adjusting sludge concentration with a consistent substrate concentration and substrate concentration with a consistent sludge concentration. The maximum PHB content in cells, maximum PHB volumetric yield and kinetics were compared to confirm the optimum OLR and the key difference in the two modes. The experimental results showed that the high OLR led to a high PHB content in cells and a high PHB volumetric yield. In this study, 0.91 kg•(kg •d)-1 was proved to be the optimum OLR for halophilic MMCs. On condition of identical OLR, the high sludge concentration led to high carbon source conversion ratio and substrate consumption rate. Then, a high sludge concentration can enhance PHB productivity and depress PHB production cost.%以嗜盐混合菌发酵生产PHB具有免灭菌程序、易提取、产量高等优势而被广泛关注。本研究集中考察了嗜盐混合菌（MMCs）发酵生产PHB过程中调整容积负荷的方式对PHB生产的影响。在研究中通过比较恒定接种生物量改变底物浓度以及恒定底物浓度调整接种生物量两种调整方式下 PHB 发酵生产的最大细胞含量、PHB 最大容积产率以及表观动力学，确定了 MMCs 的最佳 OLR，以及两种变化方式的本质差异。研究结果表明，两种方式下随着OLR升高，细胞内最大PHB的积累量和PHB容积产率也随着增加。本研究发展的嗜盐MMCs最佳OLR=0.91 kg·(kg·d)−1。在相同的OLR下，高的接种生物量始终具有高的碳源转化率和底物消耗速率。为此，采用高接种生物量发酵生产PHB可以提高PHB生产效率并降低PHB的成本。