Growth improvement and metabolic profiling of native and commercial Chlorella sorokiniana strains acclimatized in recycled agricultural wastewater

This study investigated acclimation ability of native Chlorella sorokiniana (CS-N) and commercial Chlorella sorokiniana (CS-C) in palm oil mill effluent (POME), their metabolic profile and feasibility of effluent recycling for dilution purpose. Maximum specific growth rate, mu(max) and lag time, lambda of the microalgae were evaluated. Result shows both strains produced comparable growth in POME, with mu(max) of 0.31 day(-1) and 0.30 day(-1) respectively, albeit longer lambda by the CS-C. However, three cycles of acclimation was able to reduce lambda from eight days to two days for CS-C. Metabolic profiling using principal component analysis (PCA) shows clear cluster of acclimatized strains to suggest better stress tolerance of CS-N. Finally, a remarkable mu(max) of 0.57 day(-1) without lag phase was achieved using acclimatized CS-N in 40% POME concentration. Acclimation has successfully shortened the. and dilution with final effluent was proved to be feasible for further improvement of the microalgae growth.