Hydrogen production by unicellular green alga chlorella sp. LSD-W2 isolated from seawater in Thailand

Abstract

Green algae are able to convert the unlimited sunlight energy to produce hydrogen via photosynthesis. In seawater, several kinds of m arine microalgae are widespread and abundant and have been shown to tolerate and survive under the extreme salt concentrations . This work aimed to study the screening of high H 2 producing marine green algal strains isolated from the Gulf of Thailand and the Andaman Sea, and the selection of the highest H 2 producing strain. Its H 2 production was investigated under photoheterotrophic cultivation. The result revealed that among 20 marine green algal strains, the green alga Chlorella sp. LSD-W2 gave the highest H 2 production rate in both light and dark anaerobic conditions. During photoheterotrophic cultivation Chlorella sp. LSD-W2 was rapidly grown in TAP (Tris-Acetate-Phosphate) medium and reached the stationary growth phase after 36 h of cultivation. The highest photohydrogen production rate was found in cells incubated in NH 4 Cl-deprived TAP medium. It was approximately 20-fold higher than H 2 production rate of cells in a normal TAP medium.