Construction and characteristics of artificial consortia of Scenedesmus obliquus-bacteria for S. obliquus growth and lipid production

In this work, artificial consortia of Scenedesmus obliquus and selected bacterial strains were constructed to investigate the effects of bacteria on microalgal biomass and lipid production, as well as their inter-relationship in a photoautotrophic system. Microalgal growth was enhanced when co-cultivated with single selected bacterial strains, among which Acidovorax facilis represented the largest biomass concentration increase of 24.8%, compared to the axenic culture of S. obliquus. The consortium system also enhanced microalgal lipid content, lipid productivity, and the proportion of saturated fatty acids and oleic acid. Moreover, the selected bacterial strains adhered directly to the S. obliquus cell surface, which was necessary for the establishment of significant interaction. Co-cultivation of S. obliquus and bacterial strains resulted in changes in both the concentration and composition of proteins and polysaccharides dissolved in the culture supernatant and cell-associated (bound) fractions, which partially contributed to the observed differences in microalgal biomass and lipid production.