Carotenoid Production from Sponge-associated Bacteria Isolated in the Gulf of Thailand

Abstract

This research was aimed at identifying a sponge-associated bacterium that produces carotenoids and studying optimum conditions for carotenoid production. Bacterial identification was carried out by the determination of their shape, size, colony’s color, motility, growth on semisolid medium, Gram staining, and a rapid biochemical test kit, API 20 NE. The results showed that one of the sponge-associated bacteria producing carotenoids was identified as Methylobacterium mesophilicum MAKB08-4. It produced astaxanthin as a main pigment of carotenoids analyzed by HPLC. It had an optimum astaxanthin production condition at a pH of 7, a temperature of 25o C, and an agitation rate of 100 rpm with 1% (w/v) glucose as a carbon source and the absence of NaCl addition in the Modified Zobell broth. Under the optimal condition, it had a good growth of 0.6 g/l and produced astaxanthin at 0.67 mg/l. The strain would be a carotenoid source, especially for astaxanthin applied for the food, cosmetic and pharmaceutical industries.