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16SrRNA and enzymatic diversity of culturable bacteria from the sediments of oxygen minimum zone in the Arabian Sea

IR@NIO: CSIR-National Institute Of Oceanography, Goa


Field	Value

Creator	Divya, B. Soumya, K.V. Nair, S.

Date	2010-04-27T05:08:18Z 2010-04-27T05:08:18Z 2010

Identifier	Antonie van Leeuwenhoek, vol.98(1); 9-18 http://hdl.handle.net/2264/3593

Description	Sediment underlying the oxygen minimum zone of the eastern Arabian Sea is rich in organic matter. Bacteria in this sediment-water interface are of great ecological importance as they are responsible for decomposing, mineralizing and subsequent recycling of organic matter. This study has for the first time addressed the phylogenetic and functional description of culturable bacteria of this region. Genotypic characterization of the isolates using amplified rDNA restriction analysis (ARDRA) followed by 16SrRNA sequencing grouped them into various phylogenetic groups such as Firmicutes, Gammaproteobacteria, Low G+C Gram positive bacteria, Actinobacteria and unaffiliated bacteria. Among the enzyme activities, phosphatase was predominant (52%) and was associated with all the phylotypes followed by amylase (37%) and gelatinase (33%). These hydrolytic enzymes were expressed at a wide range of temperature and pH. Firmicutes expressed most of the hydrolytic activities, consistent with a role in degradation of organic matter. Multiple enzyme expression (C is greater than or equal to 3) was exhibited by Actinobacteria (100%), followed by unaffiliated group (62.5%) and Firmicutes (61.5%). Besides hydrolytic enzymes, the phylotypes also elaborated functional enzymes such as nitrate reductase and catalase (58 and 81% of the isolates, respectively). In the oxygen minimum zone, the diversity was high with 28 phylotypes. Culturable bacterial assemblages encountered were Bacillus sp., Halobacillus sp., Virgibacillus sp., Paenibacillus sp., Marinilactibacillus sp., Kytococcus sp., Micrococcus sp., Halomonas sp. and Alteromonas sp. The high diversity and high percentage of extracellular hydrolytic enzyme activities of the culturable bacteria reflect their important ecological role in biogeochemical cycling of organic matter in the oxygen minimum zone.

Language	en

Publisher	Springer

Rights	An edited version of this paper was published by Springer. This paper is for R & D pupose and Copyright [2010] Springer.

Subject	Extracellular hydrolytic enzymes Oxygen minimum zone 16SrRNA Arabian Sea

Title	16SrRNA and enzymatic diversity of culturable bacteria from the sediments of oxygen minimum zone in the Arabian Sea

Type	Journal Article