Comparison Among The Cultivation Systems For Chlorella Pyrenoidosa And Extraction And Determination Of It's Lutein

Chlorella is a valuable microalga with the characteristics of fast growth and abundant lutein content. In the thesis, the investigations were carried out on the comparison among culture systems, heterotrophic growth parameters of Chlorella pyrenoidosa, drying methods of the algal biomass, extraction and determination methods of lutein from the cells.Six Chlorella strains were screened, and the results showed that C. pyrenoidosa 15-2070 was suitable for heterotrophic mass cultivation. The maximal biomass concentration (dry weight) was 19.8g/L in shake flasks, and cell lutein content reached 2.63mg/g. In a scale-up experiment using a 14L fermentor, cultivation parameters was as follows: inoculum, 5%(v/v); temperature, 28 ; agitation, 200r/min; air flow rate, 4~6L/min. The maximal biomass concentration (dry weight) was 20.1g/L, and cell lutein content reached 2.83mg/g. Culture biomass concentration using glucose fluid hydrolyzed from rice as C- source approached to that by using pure glucose, and cell lutein content increased to 2.92mg/g. It was shown that glucose fluid hydrolyzed from rice can be employed in mass culture as a excellent and cheap C- source.C. pyrenoidosa 1570 was cultivated in three culture systems, from which the maximal biomass concentrations (dry weight) obtained were 0.4, 19, 20.9g/L respectively, and the specific growth rates were 0.13, 0.76, 0.81d-1 respectively. It was shown that heterotrophic growth was suitable for mass culture. Chemical compositions of C pyrenoidosa cells from three culture systems were determined. Their differences were compared: the contents of fat and VC in heterotrophic cells were higher than those in autotrophic and mixotrophic cells, however, protein content in heterotrophic cells was lower than the others.Heat-sensitive compositions of C. pyrenoidosa after drying by five methods were degraded to some extent. It was concluded from theexperimental results and costs in the production that the most favorite drying methods was spray drying.The optimal parameters for lutein extraction from C. pyrenoidosa cells was shown as following: griding cells by a dispersing instrument at 30 ; methanol/dichloromethane, 2:1 (v/v); algal powder to solvent, l:75(w/v); treating times, 2 (7min every time). The efficiency of lutein extraction was 92.3% achieved under the optimized conditions.HPLC was used for determining lutein content from C. pyrenoidosa cells. Chromatographic conditions were optimized for the separation and determination of lutein, which was quick, convenient and precise.