Improved production of lipid contents by cultivating Chlorella pyrenoidosa in heterogeneous organic substrates

The study is aimed to enhance the productivity of microalgal culture by varying the organic and inorganic components during wastewater treatment. A model organism Chlorella pyrenoidosa (C. pyrenoidosa) was grown in four different sources of wastewater namely piggery, palm oil mill effluent (POME), mixed-kitchen, and domestic wastes. The growth efficacy of C. pyrenoidosa on POME was tested for their ability to remove nutrients. It was observed that POME showed the highest chemical oxygen demand of 700 mg L⁻¹. Meanwhile, the piggery waste had the highest amount of total nitrogen of 590 mg L⁻¹. C. pyrenoidosa species were reported to grow well with different nutrient sources and produce high levels of lipids. The highest content of chlorophyll a was obtained with POME (3 mg L⁻¹) and domestic wastes (2.5 mg L⁻¹). The optimum growth rate of C. pyrenoidosa was reported for POME as a substrate. Also, the results indicated the lipid content for POME (182 mg L⁻¹), domestic sample (148 mg L⁻¹), piggery (0.99 mg L⁻¹), and mixed-kitchen wastes (117 mg L⁻¹). The results above revealed that among the tested substrates, POME could be the best alternative for C. pyrenoidosa to improve the yield of lipids and ultimately, biofuels production. Therefore, the treatment of POME in wastewater using C. pyrenoidosa can boost clean technology and energy generation. In future studies, the screening of other waste effluents is needed to cultivate the microalgae and enhance biomass production to meet increasing energy demands and waste treatment applications.