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

Abstract

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, µ_max and lag time, λ of the microalgae were evaluated. Result shows both strains produced comparable growth in POME, with µ_max of 0.31 day^-1 and 0.30 day^-1 respectively, albeit longer λ by the CS-C. However, three cycles of acclimation was able to reduce λ 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 µ_max of 0.57 day^-1 without lag phase was achieved using acclimatized CS-N in 40% POME concentration. Acclimation has successfully shortened the λ and dilution with final effluent was proved to be feasible for further improvement of the microalgae growth.

Keywords: Chlorella sorokiniana; Metabolic profiling; Microalgae acclimation; Palm oil mill effluent (POME) recycling; Principal component analysis (PCA).