이산화탄소 저감 및 바이오매스 증대를 위한 미세조류 배양조건의 최적화

Abstract

Culture conditions for mass production of Chlorella sp., Dunaliella salina and Dunaliella sp. were optimized using response surface methodology (RSM). A central composite design, which was developed to facilitate the RSM, was applied to investigate the effects of initial pH, nitrogen sources and phosphate concentration on the cultivation of microalgae. Each of optimum growth condition estimated from the design was as follows : Chlorella sp. (initial pH 7.2, ammonium 17 mM, phosphate 1.2 mM), D. salina (initial pH 8.0, nitrate 3.3 mM, phosphate 0.0375 mM) and Dunaliella sp. (initial pH 8.0, nitrate 3.7 mM, phosphate 0.17 mM). Culturing of the microalgae with the optimized conditions confirmed that the maximum growth rates were attained from the parameters. The optimum CO2 concentrations of Chlorella sp., D. salina and Dunaliella sp. were 1, 3 and 1 %, respectively. The specific growth rates(μ) of Chlorella sp., D. salina and Dunaliella sp. were 0.58, 0.78 and 0.56 /day, respectively, and the The biomass productivities of Chlorella sp., D. salina and Dunaliella sp. were 0.28, 0.54 and 0.30 g dry cell wt/L/day, respectively. The CO2 fixation rate of Chlorella sp., D. salina and Dunaliella sp. were 42.8, 90.9 and 45.5 mg/L/day, respectively. Mixotrophic cultivation of Chlorella sp. with glucose increased biomass productivity from 0.28 to 0.51 g dry cell wt/L/day. But Dunaliella salina and Dunaliella sp. were not stimulated by several organic substrate (glucose, xylose, rhamnose, fructose, sucrose, galactose).