Water-soluble humic acid media for sustainable biomass, lipid, and fatty acid productions of Coelastrella striolata var. multistriata strain 047

The newly isolated Coelastrella striolata var. multistriata strain 047 derived from humic acid rich peat soil was identified and cultivated in water-soluble humic acid (WSHA) to replace the commercial AF-6 as cultivation media. The results suggested that 75% WSHA ratio showed the highest specific growth rate at 0.46/day. Moreover, cultivation of strain 047 in 75% WSHA under high light intensity of 20,000–25,000 lx resulted in 26.67 mg/L·day biomass productivity which was 1.6 times higher than in AF-6 media. Lipid production was also elevated to 46.97 mg/L with significantly increased lipid productivity of 6.71 mg/L·day by utilizing WSHA media. Fatty acid profile was dominated with oleic acid (30.5%), followed by α-linolenic acid (27.1%) and palmitic acid (16.3%), demonstrating the feasible production of omega-3, omega-6, and omega-9 fatty acids. Substitution of AF-6 to WSHA may reduce the medium preparation cost up to 92%, which highlighted that WSHA media can be used for sustainable productions of biomass, lipids, and valuable fatty acids of Co. striolata var. multistriata strain 047, especially during cultivation in high light intensity.