热泉土壤来源的纤维素降解菌的分离与初步鉴定

通过富集培养方法,从5份热泉土壤中筛选得到6株具有羧甲基纤维素(CMC)降解活性的菌株。采用原核生物保守16S r RNA核糖体基因序列分析,发现它们分别隶属于假单胞菌属、芽孢杆菌属和类芽孢杆菌属。在此基础上,对6株纤维素降解菌的生长温度、pH值、抗生素敏感性、盐离子耐受性以及羧甲基纤维素酶(CMCase)活力做了初步研究。结果表明,芽孢杆菌属的菌株WP-6和WP-3的CMCase活力最强,胞内酶活力最高达72.0 U·m L~(-1),假单胞菌株WP-2的CMCase活力最弱,胞内外酶活力均小于5.0 U·m L~(-1)。生理学结果显示,6个降解菌株都具有嗜热特点及不同程度的耐盐特性,给后续高温及盐离子耐受性纤维素酶开发提供了较好的材料。

Isolation and identification of cellulose-degrading bacteria from the hotspring soil

Six cellulose-degrading bacterial strains were isolated and identified from five hot spring soils by the enrichment and culture-dependent method. Six isolates were identified by analyzing the 16S rRNA gene sequence, and the isolates were allocated to three genera of Pseudomonas sp., Bacillus sp. and Paenibacillus sp. Moreover, the growth temperature, pH value, NaCl tolerance, antibiotic susceptibility and CMCase activity of the six isolates were determined and compared. The results showed that Bacillus spp. WP-3 and WP-6 displayed the highest CMCase, and Pseudomonas sp. WP-2 displayed the lowest CMCase to carboxy methyl cellulose (CMC) among the tested strains. The highest CMCase activity was 72.0 U·mL^-1, which was obtained from intracellular of strain WP-6, and the lowest CMCase activity was about 5.0 U·mL^-1, which was observed from strain WP-2. Physiological investigation indicated that the six strains were themesophilic and halotolerant, and the characteristics were interesting to further application studies.