Cultivation of microalga, Chlorella vulgaris under different auto–hetero–mixo trophic growths as a raw material during biodiesel production and cost evaluation

The biomass and lipid productivities of green microalga, Chlorella vulgaris TISTR 8580 cultivated in the Bold's basal medium under three different culture conditions namely AC (autotrophic), HC (heterotrophic) and MC (mixotrophic) cultivations in a 20 L rectangular bioreactor were investigated. Maximum cell growths were obtained on day 10, 3 and 5 under AC, HC and MC, respectively. The C. vulgaris cells in heterotrophic condition contained the highest amount of lipids (32.9%) and the lowest amount of proteins (14.5%). The composition of C. vulgaris cells under MC condition was found to be between those found at AC and HC conditions. The most efficient energy production system in terms of lipid production to energy consumption was MC. The biodiesel yield was about 93.3% and fatty acid in methyl esters were found as 35.33% palmitic acid, 19.01% oleic acid, 19.21% linoleic acid, 11.68% linolenic acid and 14.77% others.