生物
厚壁菌
嗜冷菌
细菌
扩增核糖体DNA限制性分析
放线菌门
极端微生物
微咸水
淀粉酶
微生物
16S核糖体RNA
微生物学
纤维素酶
生态学
核糖体DNA
酶
系统发育树
生物化学
遗传学
基因
盐度
作者
Harmesh Sahay,Bandamaravuri Kishore Babu,Surendra Singh,Rajeev Kaushik,Anil Kumar Saxena,Dilip K. Arora
标识
DOI:10.1002/jobm.201200126
摘要
Microorganisms, native to the cold environments have successfully acclimatized their physiological, metabolic, and biological features, exhibiting uniqueness in their enzymes, proteins, and membrane structures. These cold-active enzymes have immense biotechnological potential. The diversity of culturable bacteria in two different water lakes (the sub-glacial freshwater and the brackish) of Himalayas was analyzed using SYBR green staining and cultural methods. A total of 140 bacteria were isolated and were grouped as psychrophiles, psychrotrophs, and psychrotolerant organisms, based on their optimal temperature for growth. The amplified ribosomal DNA restriction analysis using three restriction enzymes facilitated the grouping of these isolates into 96 genotypes at ≥85% polymorphism. Phylogenetic analysis using 16S rRNA gene sequences revealed that the bacterial strains from both lakes belonged to Firmicutes, Proteobacteria (α, β, and γ) or Actinobacteria. Screening of the germplasm for the activity of different cold-active hydrolases such as protease, amylase, xylanase, and cellulase, revealed that about 16 isolates were positive, and exhibiting a wide range of stability at various temperature and pH. Our results suggest that the distinctly different ecosystems of sub-glacial freshwater and brackish water lakes have diverse groups of bacteria, which can be an excellent source of extracellular hydrolases with a wide range of thermal stability.
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