Effects of various abiotic factors on biomass growth and lipid yield of Chlorella minutissima for sustainable biodiesel production.

In this study, effects of different abiotic factors were studied on biomass and lipid yield of green microalga Chlorella minutissima (C. minutissima) Various concentrations of abiotic factors like nitrogen, phosphorus, glucose, iron, zinc, different values of pH, temperature, light intensity and different photoperiods were observed on the biomass growth and lipid yield of C. minutissima cultivated with modified CHU-13 medium. Initially, three cultivation media namely, Bold's basal medium (BBM), modified CHU-13 and blue-green-11 (BG-11) were used to culture C. minutissima in batch mode. Microalga cultivated with modified CHU-13 medium resulted in maximum biomass and lipid yield of 970 ± 0.21 and 356.63 ± 0.51 mg/L, respectively. To maximize biomass and lipid yield of microalga further, it was cultivated with modified CHU-13 medium and variation of above mentioned abiotic factors was done. Different biomass and lipid yields were achieved for different abiotic factors varied. Highest biomass of 1840.49 ± 0.62 mg/L was achieved with 12 g of glucose containing medium and highest lipid yield of 579.86 ± 0.76 mg/L was achieved with 0.3 g of nitrogen containing medium. GC-MS analysis of biodiesel obtained from C. minutissima biomass cultivated with modified CHU-13 medium shown the presence of C14:0, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C20:0, C20:1 and C22:0. Properties of biodiesel obtained from C. minutissima were found in compliance with ASTM-6751-02 and European biodiesel standards EN14214. These results suggest that C. minutissima can be used as a potential biodiesel feedstock for microalgal biodiesel production.