title: Cold-active hydrolases producing bacteria from two different sub-glacial Himalayan lakes.
abstract: 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.
authors.affiliation: National Bureau of Agriculturally Important Microorganisms (NBAIM), Kusmaur, Mau, Uttar Pradesh, India. harmeshsahay@rediffmail.com
authors.forename: Harmesh
authors.initials: H
authors.lastname: Sahay
authors.forename: Bandamaravuri Kishore
authors.initials: BK
authors.lastname: Babu
authors.forename: Surendra
authors.initials: S
authors.lastname: Singh
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kaushik
authors.forename: Anil K
authors.initials: AK
authors.lastname: Saxena
authors.forename: Dilip K
authors.initials: DK
authors.lastname: Arora
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D018407:Bacterial Physiological Phenomena; D003080:Cold Temperature; D004275:DNA, Ribosomal; D004795:Enzyme Stability; D006867:Hydrolases / Q000378:metabolism*; D007194:India; D060106:Lakes / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S
chemical_list: D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D006867:Hydrolases