亚硝化细菌原生质体化学诱变育种研究

Chemical Mutagenesis Breeding of Protoplast of Ammonia-oxidizing Bacteria

以活性污泥中分离出的亚硝化细菌为研究对象,采用原生质体诱变技术,以化学诱变剂氯化锂、溴化乙锭诱变亚硝化细菌原生质体,选育亚硝酸盐氮富集能力高的菌株,同时研究了诱变剂浓度与脱氮能力之间的关系。结果表明,亚硝化细菌原生质体再生菌落的致死率随诱变剂浓度的增加而逐渐增大。采用1 L模拟污水培养基扩大培养后,经2.5 mg/mL氯化锂诱变的菌株LC002脱氮率为86.89%;经2μg/mL溴化乙锭诱变的菌株EB003脱氮率为85.67%。两株诱变菌株亚硝态氮富集能力与未诱变菌株相比有明显的提高。原生质体诱变技术是一种选育优良亚硝化细菌的有效方式。

Strain with strong capacity of ammoxidation screened by repeated enrichment and separation methods from activated sludge, was collected from sewage treatment plant in China university of mining and technology. Lithium chloride and ethidium bromide mutagenesis methods of ammonia-oxidizing bacteria protoplast were used to breed mutant strain with strong capacity of ammoxidation. The relationship between concentrations of chemical mutagens and capacity of ammoxidation were researched. The results showed that regenerated colony number of protoplast decreased with increased lithium chloride or ethidium bromide mutagenic concentration. After culvation of 1 L simulation sewage medium, the mutagenic strain LC002, mutated by 2.5 mg/mL lithium chloride, still had better capacity of ammoxidation with 86.89% removal rate of ammonia nitrogen. The mutagenic strain EB003, mutated by 2 μg/mL ethidium bromide, also had better capacity of ammoxidation with 85.67% removal rate of ammonia nitrogen. Protoplast mutagenisis was an effective breeding method to breed excellent ammonia-oxidizing bacteria for further application.