Abstract:

Poly-b -hydroxybutyrate (PHB) production by halophilic mixed consortia has great advantage in cost. PHB production by the two-step production process using halophilic activated sludge cultured from estuary sediment was investigated. During the continuous 300 d, the ability of PHB storage at different F/F was assessed from the performance of the long-term tests, experiments of PHB production and the observed kinetics. The ratio of feast to famine (F/F) as an important parameter directly affected the capacity of the PHB-storing of halophilic activated sludge. At a high F/F the non PHB-storing bacteria became dominant in the enrichment reactor, while a low F/F was in favor of the selection and enrichment of PHB-storing bacteria. Moreover, the culture selected at F/F less than 0.33 showed the best PHB-storing capacity with a PHB content of 46.7% cell dry weight and a PHB yield of 0.358 mg PHB·(mg Ac)^-1. The results obtained in the study provided a guidance to the production of PHB by halophilic activated sludge.

Key words: poly-b-hydroxybutyrate (PHB), halophilic activated sludge, two-step production process, PHA- storing bacteria, culture selection, bioprocess, biotechnology, numerical analysis

摘要：

嗜盐混合菌生产PHB具有较好的成本优势。本研究接种入海口底泥发展嗜盐活性污泥,利用嗜盐活性污泥以两步法工艺生产PHB。在连续300 d的试验中从长期试验、发酵生产PHB以及表观动力学等方面探索了不同盛宴期/饥饿期(F/F)下筛选菌群的PHB积累能力。研究发现F/F作为重要的参数直接影响嗜盐活性污泥的PHB积累能力。在高F/F下非PHB积累菌群成为优势菌,而低F/F下促进高聚PHB嗜盐菌的选择和富集。在F/F≤0.33条件下筛选的嗜盐活性污泥最大PHB含量可以达到细胞干重的46.7%,PHB产率为0.358 mg PHB·(mg Ac)^-1。研究结果将对进一步实现嗜盐污泥生产PHB提供有益的指导。

关键词: 聚-b-羟基脂肪酸酯, 嗜盐活性污泥, 两步法, PHA合成菌, 菌群选择, 生物过程, 生物技术, 数值分析