Enhanced biodiesel production by optimizing growth conditions of Chlorella marina in tannery wastewater

In this study, marine microalgae such as Nannochloropsis marina, Chlorella marina, Thalassiosira sp. and Duna-liellasalina were studied for their lipid-producing ability by culturing them in secondary effluent from tannery wastewater treatment plants. Among the four marine microalgae studied, Chlorella marina showed maximum biomass and lipid yield of 3.84 g/L and 1.56 g/L, respectively, with resulting lipid content of 42%. Furthermore, chlorella species were studied under optimized culture conditions of 27 degrees C, with 8% CO2 concentration, 250 mu mol photon m-2 s(-1) light intensity and 6 mmol/L nitrogen concentration, resulting in increased biomass yield 215% L-1 day(-1). Also, the biodiesel obtained by direct transesterification yields 3.5 g/L, which is promising. Likewise, the biodiesel's oxidative stability, Iodine number, cloud point and viscosity were analyzed and were within the standards. Hence, this study signifies that tannery effluent could be a suitable feedstock for marine microalgae in biofuel production.

Automated summary

This study investigated the lipid-producing ability of marine microalgae cultured in secondary effluent from tannery wastewater treatment plants. Chlorella marina showed the highest biomass and lipid yield, and the biodiesel obtained from it also met the standards. This study indicates that tannery effluent can be a suitable feedstock for marine microalgae in biofuel production.