Enhancing Biomass And Lipid Production By Chlorella Sorokiniana?Strain UTEX 1602?,through Simultaneous Supplementation Of Sodium Bicarbonate And CO₂

Microalgal biomass is investigated as a potential feedstock for biofuel production.Enhancement of biomass,lipid,and carbohydrates content in microalgae is essential for the commercialization of microalgal biofuels.The optimal concentration of dissolved carbon in the microalgal culture medium is vital requirement for enhanced biomass production.In this study,sodium bicarbonate(0.25,0.5,1.0 and 2.0 g L-1)and CO2 enriched nitrogen gas(1%(v/v)with 0.1vvm flow rate)were simultaneously supplementation to boost carbon utilization efficiency for maximum biomass and bioproduct(lipid,protein and carbohydrate)productivities of Chlorella sorokiniana(strain UTEX 1602).The algal strain exhibits the maximum specific growth rate(0.383/day),biomass productivity(291.0 mg L-1 d-1,and CO2 fixation rate(547.16 mg L-1 d-1)at a NaHCO3 concentration of 1 g L-1.The neutral lipid 20.60%,carbohydrates 21.21%and protein yield(0.949 g L-1)were higher than the bicarbonate-free control.Additionally increases NaHCO3 concentration with the same level of CO2 can stimulate neutral lipid accumulation.The highest neutral lipid yield 30.44%was found in cell culture in the presence of 2 g L-1 sodium bicarbonate.The FAME profile showed the presence of major fatty acids was C16/C18,which are suitable for the production of biodiesel.The acquired results pointed out that a simultaneous supplementation of sodium bicarbonate and carbon dioxide is the more profitable approach of supplying carbon source to microalgae cultivation for FAME production.