Performance evaluation of Chlorella sp. BRE5 for augmented biomass and lipid production implementing semi-continuous cultivation strategy

This study aimed to evaluate the potential of indigenous microalga, Chlorella sorokiniana BRE5, for enhanced biomass production by implementing a semi-continuous cultivation strategy (SCCS). The varied start replacement points (SRP) for SCCS were evaluated under optimized renewal rate (RR) and renewal period (RP) for enhanced lipid production. The replaced culture of C. sorokiniana BRE5 with RP of both 2d and 3d with RR of 25% showed an elevated trend in biomass yield. The maximum yield in total biomass and total lipid of 7.27 g L⁻¹ and 1.66 g L⁻¹, respectively, was observed with SRP9 (9th day as SRP) at RP of 2d and RR of 25%. Semi-continuous cultivation with SRP9 shows 4.35 and 3.69 times higher in total biomass and lipid yield, respectively, than batch cultivation mode. The fatty acid methyl ester (FAME) composition of C. sorokiniana BRE5 primarily consists of C16:0 (palmitic acid) and C18:1 (oleic acid). The fuel characteristics like high heating value, better oxidative stability, and cetane number met international standards indicating its potential as a biodiesel feedstock. The optimization of SRP in semi-continuous cultivation under optimum RR and RP can be a suitable strategy for biomass and biodiesel production of microalgae.