耐高温纤维素降解菌株的筛选、鉴定及其酶活力的测定

Screening and identification of strain resistant to high temperature cellulose degradation and determination of enzyme activity

试验旨在提高奶牛粪污生物降解过程中纤维素的降解效果,对耐高温纤维素降解菌株进行筛选、鉴定及其酶活力的测定。试验以奶牛粪污异位发酵床高温期(第5 d、≥50℃)物料为菌源,采用羧甲基纤维素钠和刚果红培养基法,在50℃条件下进行分离纯化培养,采用滤纸条崩解试验、纤维素酶活测定进行筛选。结果显示:筛选出3株耐高温纤维素降解菌a2、a4和a8。3株菌株10 d内均可完全崩解滤纸条,5 d内羧甲基纤维素酶活力分别为104.32、168.92、114.98 U/mL。经16S rDNA测序及同源性分析鉴定,a2为嗜热链霉菌(Streptomyces thermovulgaris),a4和a8为地衣芽孢杆菌(Bacillus licheniformis)。研究表明,3株菌具有耐高温及高产酶等特性,可进一步应用于牛粪中纤维素的降解。

The study was to improve the effect of cellulose degradation in dairy manure biodegradation,carry out screen,identification and enzyme activity measurement of high-temperature resistant cellulose degradation strains.The experiment used high temperature period in cow dung ectopic fermentation bed material(5 d,≥50℃)as the source of bacteria,adopted the sodium carboxymethyl cellulose and Congo red culture medium method.Separation,purification and culture were carried out at 50℃,and filter paper strip disintegration test and cellulase activity determination were used for screening.The result showed that three high temperature resistance of cellulose degradation bacteria strains were screened out a2,a4 and a8.The filter paper could be completely disintegrated within 10 d,and the carboxymethyl cellulase activities within 5 d were 104.32,168.92 and 114.98 U/mL,respectively.According to 16S rDNA sequencing and homology analysis,a2 was identified as Streptomyces thermovulgaris,a4 and a8 were identified as Bacillus licheniformis.The study indicates that the three strains have the characteristics of high temperature resistance and high enzyme production,which can be further applied in application of high temperature resistance to degrade cellulose in cow manure.