10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 4 2012(October - December) This study represents the isolation and biodiversity of marine yeasts from 200-1000m depth ranges in the coastal regions of Arabian Sea. 109 strains were isolated from sea water and sediments using YM Broth containing Chloramphenicol (0.01%) and Streptomycin (0.002%) and their morphological, physiological and biochemical aspects were characterized. lessThan i greaterThan Candida lessThan /i greaterThan was found to be the major genera (41.29%) followed by lessThan i greaterThan Debaryomyces lessThan /i greaterThan (17.43%), lessThan i greaterThan Pichia lessThan /i greaterThan (12.84%), lessThan i greaterThan Rhodotorula lessThan /i greaterThan (11.01%), lessThan i greaterThan Trichosporon lessThan /i greaterThan (9.17%) and lessThan i greaterThan Cryptococcus lessThan /i greaterThan (8.26%). In both samples at 200-1000m depth regions lessThan i greaterThan Candid lessThan /i greaterThan a was the dominant genera. Among the yeasts isolated, oxidative forms were highly predominant (95.41%) and the urease producing forms were comparatively low (26.61%). The marine yeasts were examined for their hydrolytic enzyme production mainly amylase, gelatinase and lipase. The results showed that majority of the isolates had lipolytic potential. In Arabian Sea, Shannon-wiener diversity (H' (log2)), Peilou's evenness (J') and Species richness (d) were found to be higher at 500m depth region. SAVITHA K. KOILERY AND T.R. KEERTHI Isolation, marine yeast, biodiversity, hydrolytic enzymes 549-558