Abstract

Aims: To obtain axenic cultures of Thraustochytrids and assess the diversity of Thraustochytrids spps within the mangrove regions of Mumbai for their ability to produce DHA. Methods and Results: Samples obtained from various mangrove regions in and around the Mumbai coastline were screened for presence of Thraustochytrids cultures. Modified procedures involving use of various media and antibiotic treatment regimes were formulated to obtain axenic cultures of Thraustochytrids. Though 40% of the samples under study showed presence of pollen baitable Thraustochytrids, only 5% of these spps could be recovered through direct isolation techniques on the conventional penicillin streptomycin B1 agar plate. In contrast, use of antibiotic cocktail during baiting lead to better recovery such that 57.14% of all the positive pollen baited samples were able to be recovered as axenic isolates on isolation on antibiotic laden B1 agar. For most of the isolates the fatty acid profile range between 60 to 76% of their dry cell mass; with total fatty acid content of 5.92±0.41 g L^-1 of which 1.97±0.08 g L^-1 was DHA. Conclusion: Though marine mangrove environments are known habitat of Thraustochytrids its axenic cultivation is a challenge especially as the profile of contaminating bacteria and fungi within polluted areas varies from that within pristine locales. Removal of bacteria and fungi from an environment loaded with an higher organic load required mixture of three antibiotics and one antifungal; rifampicin (300 mg l^-1), streptomycin/penicillin (25 mg l^-1) and nystatin (10 mg l^-1) to be incorporated in seawater samples for a minimum of 2 days so that Thraustochytrids could be selectively isolated from the Indian Mangrove region,. Significance and Impact of Study: This data represents the first extensive study on the prevalence of Thraustochytrids across the coast of Mumbai and the combination of antibiotics that need to be used for its effective recovery.