Lipid Production And Composition In Mixed Cultures Of Rhodotorula Glutinis And Chlorella Vulgaris Cultured From Industrial Wastewater

This study investigated the biomass, lipid production, fatty acid content, and other nutrients present in microorganisms by using different culture methods:photoautotrophic pure Chlorella vulgaris cultures (PP); heterotrophic pure C. vulgaris cultures (PH); mixed cultures of Rhodotorula glutinis and C. vulgaris under photoautotrophic conditions (MP); and heterotrophic mixed cultures (MH). The four culture methods above were conducted in media and wastewater respectively.MP yielded the highest number of cells and biomass (5.9×105cells/mL and0.523g/L, respectively) in media. Furthermore, lipid production in MP culture was114.22mg/L, which is136%higher than that in MH culture (48.22mg/L). Considering the higher contents of palmitic acid (C16:0) at24.65%, oleic acid (C18:1) at56.34%, and protein at42.39g/100g in the MP culture than those in other cultures, we proposed that MP condition could be used effectively to support the growth of microorganisms. The MP culture method conducted in wastewater showed the optimum biomass and lipid content. Among the cultures, MP yielded the highest number of cells and biomass (27.73×105cells/mL and0.808g/L, respectively). Furthermore, lipid production in MP culture was117.73mg/L, which is4-fold higher than that in PP culture (23.1mg/L) and lipid content in MP culture was194.27mg/g. Considering the higher contents of palmitic acid (C16:0) at24.65%, oleic acid (C18:1) at56.34%in the MP culture than those in other cultures, we proposed that MP could be used effectively to support the growth of microorganisms. Orthogonal optimization of this culture conditions was carried out:the initial pH of7.0, the light216μmol/(m2·s), culture temperature30℃, the ratio of yeast and microalgae is2:3. The biomass was0.95g/L under this optimized culture conditions.Therefore, mixed cultures of Rhodotorula glutinis and C. vulgaris under photoautotrophic conditions is a conducive way to microbial growth, effectively improving the lipid production. This approach can provide a theoretical basis for culture as a source of microbial biodiesel production.