常温纤维素降解菌的分离与鉴定

Isolation and identification of cellulose-degrading bacteria under room temperature

目的分离培养常温下能降解纤维素的细菌。方法采集腐烂植物样本6份、表层土壤样本6份和污染水体样本2份;在22℃条件下,采用复合纤维素培养基筛选,羧甲基纤维素钠刚果红平板分离,富集培养基扩增培养;重复多次操作,测定纤维素酶活性后获得常温下具有纤维素酶活性的菌株;提取细菌基因组DNA,对16S rDNA进行测序,并与Genebank对比,鉴定其种属。结果分离出3株常温下具有纤维素酶活性的细菌,其纤维素酶活性分别为0.028、0.57和1.2μg/min。经鉴定,3株细菌与类芽孢杆菌属、暂定种金黄色杆菌和金黄杆菌的匹配度分别为99%、97%和97%。结论从腐烂的树叶、腐烂树叶下的表层土壤和污染水体中均能分离出常温下具有纤维素酶活性的菌株。

Objective To isolate and culture the bacteria that can degrade cellulose under room temperature. MethodsSamples of decayed leaves（n=6）,surface soil（n=6） and polluted water（n=2） were collected,and were seeded into multiple fiber media.Compound cellulose media were used for screening,carboxymethyl cellulose sodium（CMC-Na） plates were employed for isolation,enriched media were adopted for culture,and cellulose-degrading bacteria were obtained after cellulase activity detection under temperature of 22 ℃.Genomic DNA was extracted from these bacteria,and was sequenced with universal primers for 16S rDNA.The results of sequencing were aligned with the data of Genebank to identify the target bacteria. Results Three strains of cellulose-degrading bacteria were isolated,with the cellulase activity of 0.028 μg/min,0.57 μg/min and 1.2 μg/min,respectively.Sequencing analysis revealed that the matching rates between these 3 strains of bacteria and Paenibacillus,Candidatus Chryseobacterium massiliae and Chryseobacterium were 99%,97% and 97%,respectively. Conclusion Cellulose-degrading bacteria can be isolated from decayed leaves,surface soil and polluted water bodies under room temperature.