Impact of glyphosate herbicide stress on metabolic growth and lipid inducement in Chlorella sorokiniana UUIND6 for biodiesel production

The influence of glyphosate herbicide stress was investigated in the freshwater green microalgae Chlorella sorokiniana for metabolic growth and lipid induction. Glyphosate herbicide concentration at 30.10 ppm (IC50) elicited half-maximal inhibition during 96 h of incubation. After 24 days of harvest, C. sorokiniana produced 442.18 +/- 9.1 mg/L and 427.73 +/- 5.0 mg/L dcw of biomass in the control media and glyphosate IC50, respectively. A nominal reduction in biomass production was observed (similar to 3.26%) due to stress in metabolic biosynthesis in glyphosate IC50, media. However, in contrast to biomass production, glyphosate IC50, stress aided in the induction of lipid biosynthesis in microalgae cells. The improvement in lipid synthesis was found to be similar to 17% higher in glyphosate IC50, compared to control. The chemical construction of the biomass, metabolites, and lipids of C. sorokiniana was analyzed via FTIR spectroscopy. The lipids extracted from C. sorokiniana were used for methanolic-H2SO4 catalyzed transesterification for the production of biodiesel. The synthesized biodiesel was analyzed by FTIR and H-1 NMR. The conversion efficiency of microalgae lipids into biodiesel was estimated at similar to 77%. This study insights the use of glyphosate in lipid induction in microalgae to produce renewable and sustainable biofuels for the clean environment.