Study On High-density Cultivating Spirulina Platensis In A Flat Photobioreactor

Spirulina is one of the most abundant and comprehensive organisms in the natural world.The high-density cultivation of spirulina in photobioreactor increasingly becomes a hot research at home and abroad.In this study,Spirulina platensis was used as material and the cultivation condition of spirulina in flatbed photobioreactor,the process of phycocyanin production from spirulina and phycocyanin preparation conditions were optimized and explored.First,the basic conditions for the cultivation of spirulina was determined.Spirulina platensis was screened,separated and purificated in the flask to elect the healthily growing algae filaments.Subsequently,it was determined through experiments that spirulina production significantly increased with the optimum initial inoculation of 10%,most preferably initial pH9.0-9.5,the addition of 3 g·L-1 glucose,3 g·L-1 sodium thiosulfate or 2 g·L-1 of sodium sulfite.Spirulina was cultivated in flat panel photobioreactor reactor.It was found that biomass of spirulina reached peak as the glucose concentration reached 4 g·L-1 and sodium sulfite concentration reached 3 g·L-1.Further,by adjusting the illumination pattern,ventilation and proper nutritional supplement,the average growth rate and algae biomass could be up to 0.85 gDW·(L·d)·-1 and 10.02 gDW·L-1 under above-mentioned optimal production conditions.Efficient cultivation of spirulina does not mean efficient output of phycocyanin.Therefore under the premise of not affecting the growth state of spirulina,the experimental process was optimized to obtain efficient amount of phycocyanin.It was found that the optimal conditions obtained was:power of 600 W,time of 80 min,temperature of 35?and extract of the PBS buffer.Different modalities of cultivation were compared to optimize phycocyanin output in this study,and the optimal mode was obtained:the double side light source(8000 lx)after the first one side light source(4000 lx),CO2 flow rate of 1100 mg·(L·d)-1 and ammonium nitrate of 5 mM.Phycocyanin production reached the highest on the 6th day after inoculation.