Abstract:

To enhance the microalgae lipid content, Chlorella sp. was subjected to ultrasonic mutagenesis. Mutagenesis was performed for 20 minutes under conditions of 40 kHz and 100 W, resulting in the cultivation of 10 mutant strains (M1-M10). Further screening led to the selection of three stable high-lipid-producing strains, namely M2, M5, and M7. These strains were analyzed to determine their biomass concentration and lipid, chlorophyll, and protein mass concentration and percentage. The results indicated that the biomass mass concentrations of M2, M5, and M7 were 0.384, 0.379, and 0.443 g/L, respectively. The lipid yields of M2, M5, and M7 were 14.70, 13.34, and 25.11 mg/L, respectively, all of which were higher than that of the wild type (WT) strain, which had a recorded yield of 9.38 mg/L.Compared to the WT, the chlorophyll yield of the mutant strains increased by 14.41%, 3.01%, and 10.24%, respectively, while the protein content of the mutant strains increased by 7.30%, 10.52%, and 13.66%, respectively. This study is of great significance to the industrialized production of biodiesel.

Key words: Chlorella sp., ultrasound, biomass, lipid, chlorophyll, protein