Study On The Method Of Microalgae Collection By Bacterial Cellulose Produced By Gluconacetobacter Xylinus

Microalgae has high comprehensive utilization value and broad application prospects,but the harvest of microalgae has become a bottleneck affecting its large-scale production.Existing microalgae harvesting technology has high cost and low applicability,and it needs to find a more extensive,efficient,inexpensive and environmentally friendly microalgae harvesting method.This study explored a method for the collection of microalgae by on-line flocculation with bacterial cellulose produced by Gluconacetobacter xylinus.Its research content is as follows:In the present study,Chlorella vulgari,Scenedesmus obliquus and Chlamydomonas reinhardtii were used as study objects.Glucose/Yeast extract medium(G/Y medium)was added to microalgae culture with different concentrations to form a mixed solution,which inoculate Gluconacetobacter xylinus to produce bacterial cellulose to effectively flocculate three kinds of microalgae.The addition amount of G/Y medium had different effects on the flocculation efficiency for three kinds of microalgae,and the time achieving the maximum flocculation efficiency was quite different.After C.vulgaris was inoculated in 30%G/Y medium,the highest flocculation efficiency could reach 90%at 48 h.After inoculated with 10%G/Y medium,the flocculation efficiency of 8hd reached the maximum value of 90%.After C.reinhardtii was inoculated in 40%and 50%G/Y medium,the flocculation efficiency was close to 100%at 8h.The mixed culture recovered after flocculation was added to fresh microalgae culture with different addition amounts.The harvesting efficiency of C.vulgaris and S.obliqunus was found to be same as that of adding fresh G/Y medium.The harvesting efficiency of C.reinhardtii was partially reduced compared with the addition of fresh G/Y medium,but the harvest efficiency of addition of 40%the recovered culture could also reach 87.9%.The result indicated that the recovered culture can successfully recycling.Through the observation of flocculating efficiency of different rotational speed in the flocculation process,G.xylinus inoculation,and microalgal biomass,the flocculation procedure of the microalgae were optimized.The maximal harvesting efficiency of C.vulgaris,S.obliqnus and C.reinhardtii was found to be 92%,91%and 97%,respectively with stationary conditions.The inoculation of 5%G.xylinus is beneficial to the formation of flocculation.The biomass in the algal fluid has little effect on the flocculation efficiency.The observation of light microscopy and electron microscopy of the flocculation mass of microalgae revealed that the cellulose produced by G.xylinus was cross-linked and the microalgae cells were d.The infrared spectrum absorption showed that the enwrapped microalgae did not affect the bacterial cellulose,so that the clumps almost retained the unique characteristics of bacterial cellulose.By measuring the maximum photosynthetic quantum yield(Fv/Fm)of the microalgae cells in the flocculation masses,it was found that the encapsulated microalgae cells had basic photosynthetic activity.