| With oleaginous Chlorella pyrenoidosa as origional strain,the effects of different cultivation modes (autotrophic, heterotrophic and mixotrophic cultivations) on the biomass and oil content of the microalga and the effects of glucose mass concentration, type and mass concentration of nitrogen source in the heterotrophic medium on the growth of the microalga were investigated. The results showed that Chlorella pyrenoidosa had the highest biomass and oil content by heterotrophic cultivation in comparison to the autotrophic and mixotrophic cultivations. The main fatty acids of Chlorella pyrenoidosa oil by heterotrophic cultivation were palmitic acid (36.07%), oleic acid (34.26%), linoleic acid (20.17%) and linolenic acid (6.12%) based on the GC results. The optimal heterotrophic cultivation conditions for Chlorella pyrenoidosa growth were obtained by single factor experiment as follows: glucose mass concentration 60 g/L,with yeast as nitrogen source and the mass concentration 4 g/L. Under the optimal conditions, Chlorella pyrenoidosa achieved 12.43 g/L of biomass and the oil yield was 5.45 g/L after fermentation for 192 h. These results showed that Chlorella pyrenoidosa oil obtained by heterotrophic cultivation was a potential and new edible oil source. |
