Abstract
Following the diminishing hopes from the first and second generation biofuels, mainly due to the limitations of land availability, feed stock requirements, and complicated pre-treatments, third generation biofuels from microalgae are becoming a priority in the current scenario. The present study focuses on comparison and optimization of lipid accumulation efficiency in algal strain Chlorella minutissima grown under autotrophic, heterotrophic, and mixotrophic modes of nutrition, employing various carbon sources obtained from cheap industrial wastes such as glucose, acetate, and glycerol. Other pertinent factors such as the effect of various nitrogen sources, effect of salinity on the cell growth, and lipid accumulations in the algal cells were also studied. The results suggested that C. minutissima can grow efficiently under autotrophic, heterotrophic, and mixotrophic modes of nutrition. C. minutissima cells were capable of utilizing other non-popular carbon sources such as glycerol and acetate collected as waste products from different industries along with commonly used glucose. The maximum biomass concentration (8.9 g/L) and lipid content (36.19 %) were found in heterotrophic mode of nutrition. Our findings indicated that C. minutissima can efficiently utilize these cheaper carbon sources from industrial waste products for its growth and the production cost of various bioenergy sources can be reduced significantly.