微藻光合反应器培养对高浓度氧的抗性机制研究

Photobioreactor(PBR), a hot research area and very important potential platform for downstream biotechnology, have being facing tough problems in its industrialization and scaling up owing to the physiological hindrance by high DO and high temperature in the PBR, the high cost in its construction and operation and so on. In this project, to investigate the feasibility in industrialization or large-scale production of microalgae in PBR, resistance of seawater Spirulina to high DO and high temperature has been studied, and a series of PBRs have been constructed to test if the structure of the PBR can be simplified, the cost of the PBR can be lowered, and the problem of physiological inhibition or even harms by high DO, high light irradiance and high temperature can be resolved by use of seawater Spirulina. It was showed that seawater Spirulina can endure very high DO up to 29μg/ml, and to 26μg/ml even under stress of high light irradiances, and that seawater Spirulina can survive under very high temperature over 56℃，and keep well growing under 49℃ and stress of photo oxidative. It was proved that under the outdoor conditions, centrifuge-pump tubular PBR and diaphagm-pump tubular TPR are not suitable for the cultivation of Spirulina, the maximum growth rate of Spirulina reached 0.3g in air-lift tubular PBR and 2.5g l-1d-1 in bellows-pump PBR, 20-50 times higher than the grow rate in outdoor ponds . The maximum cell density of seawater Spirulina in bellows-pump can reach 13g/l，5-10 times of that in the outdoor ponds , presenting a prospective future for industrialization and scaling-up of PBR。.It was showed that phycocyanin, SOD, carotenoids and chlorophyll is related to the resistance of seawater Spirulina to high DO, high light irradiance or high temperature which is affected by the high salinity, Ca2+ and Mg2+. Phycocyanin may play a very important role in the resistance to high DO, for it was proved of anti-oxidative function and it was more stable in seawater Spirulina than in freshwater Spirulina under photo-oxidative conditions . From the original 48%, The total protein content of the seawater Spirulina rise up to 65-72%, accompanied by the drop of polysaccharide content, when it grew under stresses of high light, high temperature and high oxygen, and in the PAGE spectrum of which, it comes out a new stripe which did not exist in seawater Spirulina growing under normal conditions. Above results may mean the possibility of gene regulation in the adaptation of seawater Spirulina to the stresses.Part of the above achievements has been successfully applied to microalgae industries for the renewing of the traditional cultivation techniques in open ponds system , new product development and cultivation of other microalgae in PBR, and has been applied to large-scale reproduction of Epinephelus malabaricus as well, presenting a prospective future in the research area of PBR industrialization and resistance mechanism to stresses.

本项目拟以螺旋藻为模式材料，研究微藻在光合反应器培养中对系统内高浓度氧的抗性机制，模索可诱导微藻产生抗氧特性的培养条件并初步探索抗氧特性的分子基础，可望在生物抗氧机制的研究上产生新的思路和取得新的突破，同时，为突破或缓解光合反应器的氧障碍并推动这一技术的产业化打下基础，取得具有较高创新水平的理论和应用成果．