【摘要】 以真养产碱杆菌 (Alcaligeneseutrophus)为聚 β 羟基丁酸 (PHB)的生产菌株 ,在分析了PHB发酵过程参数变化的基础上 ,进一步探讨了PHB合成期不同的硫酸铵流加速率对PHB合成的影响。研究结果表明 ,在PHB合成阶段 ,培养基中氮源的完全缺乏 ,导致细胞合成PHB能力的下降 ;在PHB合成期 ,不同的氮源流加速率对PHB合成过程存在着显著的影响 ,当流加速率较小时 ,尽管最终胞内PHB含量很高 ,但细胞干重、PHB浓度和PHB生产强度都较低。当氮源流加速率过大时 ,会导致最终胞内PHB含量显著下降 ,使PHB浓度和PHB生产强度降低。当硫酸铵流加速率在 0 5g/h左右时 ,可以得到较好的发酵效果。更多还原

【Abstract】 On the basis of analysis of PHB fermentation processes, the effects of ammonium sulfate feeding rate at PHB formation period on the PHB accumulation by Alcaligenes eutrophus were investigated. It was shown that the complete absence of nitrogen source at PHB formation phase would lead to the decline of PHB synthetic activity, and the obvious influences of different nitrogen feeding rate on PHB synthesis were observed. Higher PHB content, but relative lower cell dry weight, PHB concentration and PHB productivity could be obtained at slower nitrogen feeding rate. The excessive nitrogen feeding rate resulted in the drop of PHB content, which led to the decrease of PHB concentration and PHB productivity. The better results could be achieved when the ammonium sulfate feeding rate was set at around 0.5g/h.更多还原