利用餐厨垃圾水解酸化液合成PHA——耐盐菌的筛选及其产PHA特性

SCREENIGN OF PHA-ACCUMULATING HALOTOLERANT BACTERIA AND ITS PHA SYNTHESIS PROPERTIES FROM SIMULATED FOOD WASTE HYDROLYSIS ACIDIFICATION SOLUTION

利用尼罗蓝染色法从盐分含量高的垃圾渗滤液处理系统中分离出8株具有PHA合成能力的菌株,通过气相色谱法定量分析PHA产量,进一步筛选出PHA合成能力较强的1株细菌,利用16S rDNA序列分析鉴定菌种,并研究了含盐量和pH对菌株积累PHA特性的影响。结果表明:筛选出的PHA高产菌为蜡样芽胞杆菌(Bacillus cereus)。在盐胁迫下细菌体内的PHA含量提高,在含盐量在5%以内时,盐分对合成PHA产量影响较小,PHA最高产量为61.2 mg/L,最低为57 mg/L,说明该菌有一定的耐盐性。在pH为5~8内,细菌细胞干重变化不大(184.4~199.4 mg/L),最佳pH值为5,此时PHA产量达84.2 mg/L。红外光谱分析表明,利用蜡样芽胞杆菌所得PHA样品具有和标准品相同的化学结构。

Eight kinds of PHA-accumulating strains were isolated from landfill leachate treatment system with high salt content by Nile blue staining. A higher PHA-accumulating strain was screened by quantitative analysis using gas chromatography. The strain was identified by 16S rDNA gene sequencing. The results showed that the high PHA-accumulating strain was Bacillus cereus. Under the stress of salt,the PHA production capacity increased. When the salt content was less than 5%,salt had less effect on PHA yield,which indicated that the strain was salt-tolerant. The dry weight of bacterial cells did not changed obviously（184. 4 ~ 199. 4 mg/L） in a pH range of 5 ~ 8. When the optimal pH was 5,the yield of PHA reached 84. 2 mg/L.The infrared spectroscopic analysis showed that the samples obtained by Bacillus cereus strain had the same structure as the standard products.