Summary of Abstract Submission

Abstract Submission No. IO50-09-0075PresentationPoster

STUDY ON SULFUR OXIDIZING BACTERIA IN THE NORTH INDIAN OCEAN

Larissa Menezes*1, Genevieve Fernandes1, Samir Damare1

1 CSIR-National Institute of Oceanography, India

ABSTRACT :

Sulfur oxidation involves conversion of hydrogen sulfide (H2S), thiosulfate (S2O32-), tetrathionate (S4O62-) into elemental sulfur (S0) or sulfate (SO42-), biologically or chemically. The presence of H2S in the environment can be toxic to its biota and so its conversion to a non toxic state i.e. elemental sulfur or sulfate is necessary. In biological sulfur oxidation, some marine bacteria convert H2S to elemental sulfur or sulfate. These sulfur oxidizing bacteria (SOBs) are known to thrive in low-oxygen marine environments. Thus, an attempt was made to isolate sulphur oxidizing bacteria from the oxygen minimum zone (OMZ) of the North Indian Ocean. Different media were used for isolation of SOBs from sea water wherein the sulphur sources varied in each medium in the form of sulfide, thiosulfate or elemental sulfur. Water samples were collected from the upper interface, mid-OMZ and lower interface of the oxygen minimum zones which were filtered through 0.22Ám nitrocellulose membrane and inoculated on media to obtain bacterial isolates. The 16S rDNA of these isolates was amplified using 27F and 1492R primers and the amplicon was sequenced for identification of the bacteria. Out of the 260 bacterial isolates sequenced, three isolates were identified as SOBs namely, Alcanivorax dieselolei, Citreicella thiooxidans and Pseudomonas stutzeri. These genera are reported to contain genes responsible for sulfur oxidation and could be significant in the sulfur cycle of the oxygen minimum zone of the North Indian Ocean.