Kinetic Analysis And Optimization For Heterotrophic Cultivation Of Chlorella

Chlorella is a unicellular microalga containing abundant nutritious substances such as protein, carotenoids, polysaccharide, vitamins, Chlorella growth factor, etc. It is effective in anti-oxidation, anti-tumor, enhancing immunity and preventing cardiovascular disease and so on. Chlorella is noted for its high cellular lutein content, which makes it a potentially resource for lutein production. Comparing to other lutein resources, Chlorella has many advantages such as the high specific growth rate and the ability of growing heterotrophically. However, there is still a large gap in the cultivation efficiency and yield level between heterotrophic Chlorella and other microorganisms such as yeast. In order to establish a high efficient system for heterotrophic cultivation of Chlorella and lutein production, following aspects were included in this study:(1) Several cultivation parameters influencing cell growth and lutein production by heterotrophic C. pyrenoidosa, including inocula, aeration and initial concentration of glucose, KNO3, KH2PO4 and MgSO4 in the medium were investigated and optimized by means of flask experiments. Uniform design experiments were performed to analyze the comprehensive effects of the four major components in medium on cell growth and lutein production by C. pyrenoidosa, based on which multiple regress models were developed. It was found that sufficient areation was necessary for both cell growth and lutein formation. Glucose concentration and C: N ratio were found to be two predominant factors influencing the cell gowth and lutein production by C. pyrenoidosa. In the range between 10 - 60 g/l, higher initial glucose concentration resulted in higher final biomass concentration and lutein yield,...