Study On The Optimization And Primary Scale-up Of High-density And High-quality Preparation Technology Of Chlorella Pyrenoidosa

Chlorella was widely used in food, energy, feedstuff, pharmacy and other fields.A novel "Sequential Technique of Heterotrophic Cultivation-Dilution-Photoinduced Culvatition" (STHDP) was invented by our laboratory, and high-density and high-quality cultivation for Chlorella can be realiszed by using it. However, the technology needed to be optimized and scaled up in order to promote its industrialization processing.In this paper, first of all, semi-continuous heterotrophic cultivation of Chlorella pyrenoidosa was scaled-up primarily in 500L bioreactor. Moreover, photoinduced system and process were optimized respectively in order to establish the small-scale photoinduced cultivation system and process which can be scaled up. Furthermore, the pilot-scale photoinduced cultivation system was estabilished. Then, the spray drying conditions of aglae powder was optimized and the component of aglae powder were tested systematically. In addition, semi-continuous heterotrophic cultivation applied for Chlorella vulgaris was studied.(1) Semi-continuous heterotrophic cultivation of C. pyrenoidosa was scaled up in the 500L bioreactor. Productivity of cell, average specific growth rate and cell yield on glucose reached 2.5 g/(L-h),0.02-0.03 h-1 and 0.48 g/g in the semi-continuous cultivation which were similar to 50L bioreactor. The result showed the scale-up of this technology was feasible.(2) The effects of different photoinduced systems, algae cell harvested from different stages of heterotrophic culvatition, light and dark cycle, cell densities and air fluxs on the quality improvement of C.pyrenoidosa during photoinduced phase were investigated respectively. According to the results of small-scale open photoinduced system, the raceway pond which matched 3 tons bioreactor was built for C. pyrenoidosa preliminary photoinduced cultivation.(3) The spray drying conditions which impacted the yield of aglae powder was optimized by response surface methodology, and the optimal spray drying conditions was obtained:the inlet air temperature was 200℃, the feed concentration was 77.8 g/L, the feed flow rate was 100 mL/h. The component of Cpyrenoidosa powder cultivated by the STHDP were analyzed systematically, and the result showed that the most of indexes were almost in accordance with the quality standards established by BluBio Tech Company in Germany.(4) The heterotrophic cultivation of Chlorella vulgaris was optimized, and the semi-continuous heterotrophic cultivation of C. vulgaris was developed for the first time. In addition, the main factors which impacted the scale-up of semi-continuous heterotrophic cultivation of C. vulgaris were analyzed.