Photosynthetic transients in Chlorella sorokiniana during phycoremediation of dairy wastewater under distinct light intensities

The present study is aimed to understand the photosynthetic transients of Chlorella sorokiniana SVMBIOEN2 during treatment of dairy wastewater under different light intensities (100, 150, and 200 mu mol m(-2)s(-1)) in mixotrophic mode. Light intensities showed marked influence on photosystem behavior, lipid profile, and organic pollutant removal. Analysis of Chlorophyll a fluorescence transient including Fv/Fm, ETo/RC, TRo/RC, and Abs/RC showed better photosystem efficiency at 100 mu mol m(-2)s(-1) operations. OJIP curve fitting depicted a positive L-band at 150 mu mol m(-2)s(-1) indicating lower kinetic energy of photosystem II (PSII) reaction centres at high light intensities. Better photosynthetic activity at 100 mu mol m(-2)s(-1) operations resulted in good assimilation of biomass (2.3 g L-1), carbohydrates (10.2 mg g(-1)), and proteins (14 mg g(-1)) with a significant reduction in chemical oxygen demand (85%). Phycoremediation of dairy wastewater accumulates predominantly monounsaturated fatty acids followed by polyunsaturated fatty acids showing the application of C. sorokiniana in nutraceutical and food industries.

Automated summary

The study revealed that a light intensity of 100 mu mol m(-2)s(-1) enhances the photosynthetic efficiency of Chlorella sorokiniana SVMBIOEN2 and effectively removes chemical oxygen demand from dairy wastewater; meanwhile, a high light intensity of 150 mu mol m(-2)s(-1) can reduce the kinetic energy of chlorophyll a, influencing the dynamics of photosystem II reaction centers.