Effect of Nitrogen on Growth and Lipid Content of Chlorella pyrenoidosa

Problem Statement: In today’s scenario, microalgae are widely recognized as a promising source for biofuel production as a renewable source of energy. They are exceedingly rich in oil, which can be converted to biofuel. This paper deals with one of the method to enhance the lipid content in microalgae. Approach: Microalga, Chlorella pyrenoidosa, was grown autotrophically in batch culture and the effect of different concentrations of nitrogen source (0-0.4 g L^-1 KNO₃) on growth and lipid content was studied. Results: As the nitrate concentration in the medium decreased, biomass production also decreased but the lipid content increased. Moreover, at the same concentration of nitrate source, lipid tends to accumulate more in stationary phase in comparison to exponential phase. Highest lipid accumulation of 26% was recorded in the culture with 0.05 g L^-1 KNO₃, which is one-fourth of basal nitrogen source concentration. Conclusion: The present study suggested that nitrogen starvation is the effective approach to enhance lipid for biofuel production.