Strategies to enhance lipid productivity in microalgae: Role of cell disruption and media composition

Abstract

The major bottleneck in biofuel production from microalgae is the optimization of biomass productivity, lipid productivity, and the lipid extraction process. The diverse cell structure of microalgae results in variation in algal growth and the yield of intracellular content. Therefore, it is quintessential to study the algae thoroughly under varied pretreatment and extraction conditions in order to make downstream processing affordable and cost-effective in large-scale production. In this study, Chaetophora sp., Microchaete sp., and Nostoc sp., isolated from a freshwater pond, were subjected to various physical and chemical disruption techniques to extract lipid. Further, the effects of nitrate and phosphate concentrations on biomass and lipid productivity were statistically assessed. Lipid yield was higher when algal cells were subjected to sonication and microwave disruption followed by extraction using a modified Folch’s method. The BBM supplemented with 0.125 g l−1 of sodium nitrate, 37.5×10−3 g l−1 of dipotassium phosphate, and 87.5×10−3 g l−1 of potassium dihydrogen phosphate was found to be ideal for cultivating Chaetophora sp. for the purpose of biofuel. While Microchaete sp. and Nostoc sp. showed better biomass and lipid productivity in BG11 media supplemented with 7.5 g l−1 of sodium nitrate and 37.5×10−3 g l−1 of potassium phosphate.