The Research And Application Of Heterotrophic Chlorella Seed Storage Technology

The cultivation of heterotrophic Chlorella overcomed the shortcomings appeared in the process of the traditional cultivation of Chlorella, such as the large area occupied, the long-period, the high harvesting costed, and the susceptible to pest infestation. But its highest growth rate was only 8 g/(L·D), and its growth cycle was up to 15 d, and its contamination rate was as high as 70%, compared with bacteria, yeast and other microorganisms, it still had the problems of low production efficiency, and high production cost, and its industrialization was extremely difficult. At present, the domestic research on heterotrophic Chlorella only stays in breeding of algae, downstream extraction development, while cell culture was the key link in the process of heterotrophic Chlorella of production. If the problems existing in the process of cell culture cannot be solved, the industrialization won't be achieved.This research focuses on the improvement of the efficiency and success rate of cell culture, and begined from the screening of seed preservation methods and antimicrobial agents. In order to achieve a rapid inoculation, and a high proportion inoculation, it chooses the best antibacterial agent and the optimization of seed preservation technology. On this basis, heterotrophic Chlorella could reach the logarithmic growth phase rapidly, so as to shorten the training cycle, thereby reducing energy consumption. While the application of antimicrobial agents solved the problem of bacterial contamination, and the cost of production was reduced greatly. The following conclusions were obtained in the study:1.15% inoculation amount and preservation of 2 months was used in of liquid-solid preservation method,under these conditions,90% survival rate was obtained by preservation method and the purpose of seed preservation is achieved.2. Skim milk was choosed as protective agent, and the adding ratio of protective agent was 10%, Inlet temperature was 110?, air intake frequency was 30 Hz,feed flow rate was 12 mL/min, under this condition of spray drying method, the survival rate of heterophic Chlorella was up to 29.3%, and its powder collecting rate could reach 65.5%.3. Sucrose was used as protective agent, and the protective agent adding ratio was 15%, in the centrifuge speed was 5000 r/min,10 min, centrifugal drying time was 1 h, material thickness was 10 g/mm2, under this best process parameters of the vacuum freeze drying preservation method, Chlorella cell survival rate could reach 43%.4. The optimal process parameters of Immobilized preservation method were as follows:the concentration of calcium chloride was 1%, the concentration of sodium alginate was 3%, and the immobilization time was 16 h, under these conditions,5 min permeability of the ball was 85%, the integrity of the ball was 80%.5. In the conventional laboratory, heterotrophic Chlorella was cultived 5 d in the open environment, the addition of ansamitocin and thiabendazole, could avoid Infecting bacteria, because of the differences in strain characteristics, the bacteria and the thiabendazole had little influence on heterotrophic Chlorella. The cultivation of penicillin and potassium sorbate could suppress heterotrophic Chlorella. The addition of 100 mg/L was selected and cultived for 5 d in the open environment in the conventional laboratory exposure, The results showed that the fermentation results were close to that of the control group. Adding ansamitocin of 100 mg/L could not only ensure the training process was not infected by the bacteria and does not affect the normal growth of Chlorella cells.6. The fermentation results were better than the other test group by using the liquid-solid test group, under this conditions its mass volume concentration could reach 130 g/L in 257 h. the liquid-solid succeeding preservation could improve the efficiency of heterotrophic growth effect, the liquid-solid succeeding preservation was applied in kiloton algae powder production line and ansamitocin was added, annual savings of material and energy loss amounted could up to 172200 yuan.