一株聚-β-羟基丁酸酯高产菌株的筛选及发酵条件的优化

摘要

To obtain a strain which can use inexpensive carbon source to synthesize poly-β-hydroxybutyrate(PHB) in a short time , a bacterium CCZU-6X with high production of poly-β-hydroxybutyrate (PHB) was isolated and purified from soil , which was identified as Rhodococcus sp. according to its morphological,physiological properties and 16S rDNA sequence analysis. The optimum fermentation conditions were found as follows:the most suitable carbon source was 10 g/L lactose,and nitrogen source was 2 g/L ammonium sulfate,initial pH 7.5,250 mL flask containing 30 mL medium,30 ℃,shaking at 160 r/min for 18 h. Under the optimum conditions,the production of PHB was 4.54 g/L,as high as 79.52%of dried cell weight.%为了获得利用廉价碳源在细菌胞内快速大量合成聚-β-羟基丁酸酯（poly-β-hydroxybutyrate，PHB）的菌株，通过苏丹黑染色法，从土壤中分离筛选得到一株聚-β-羟基丁酸酯（PHB）高产菌株CCZU-6X，经形态观察、生理生化实验和16S rDNA序列分析，鉴定该菌为红球菌属（Rhodococcus sp.）。该菌株的最佳发酵条件为10 g/L乳糖、2 g/L硫酸铵、起始pH值7.5、装液量30 mL/250 mL、转速160 r/min、温度30℃、发酵时间18 h，在此优化条件下PHB的积累量达到细胞干重的79.52%，产量为4.54 g/L。