Alkaline lipase activity from the marine protists, thraustochytrids

Abstract

Two thraustochytrid protists of the genus Thraustochytrium isolated from coastal and mangrove habitats of Goa, India were studied for extracellular alkaline lipase production. Maximum lipase production was supported by a combination of peptone and yeast extract in the growth medium while strong inhibition of enzyme production was observed in presence of glucose. The inducible nature of the enzyme production was evidenced by the requirement of olive oil in the medium. Lipase production was salt-dependent and optimum production required 3.4 percent (w/v) crude sea salt. Ideal conditions for maximum production of lipases were therefore adopted as incubation at 30 +/- 2 degrees C for 168 h at an initial pH of 6.0 in a medium consisting of 0.5 percent peptone, 0.01 percent yeast extract, 0.5 percent olive oil and 3.4 percent crude salt. Extracellular lipase production by the two thraustochytrid isolates [designated TZ (ATCC/PRA-295) and AH-2 (ATCC /PRA-296)] was increased threefold under these optimized culture conditions. This appears to be the first report on optimization of cultivation conditions for the production of alkaline lipases by thraustochytrids.