Entomogenous Fungi Cordyceps Cicadae Flocculant-producing Mechanism And Its Application In Coal Washing Wastewater In Eco-treatment

Compared to traditional inorganic and organic flocculants,microbial flocculant was high security,no secondary pollution,and strong turbidity wide range of applications.Microbial flocculant had a prospect of application in the field of water treatment chemicals.Microbial flocculant has become the focus of research and development of new type water treatment agent.Cordyceps cicadae is an entomogenous fungi,which is a kind of infection with multiple piercing-sucking mouthparts pests,and is a resource of high security as the traditional Chinese herbal medicine which has thousands of years of history of medicine.Previous research showed that Cordyceps cicadae could produce microbial flocculants.But there did not systematically study on it.Therefore,this article used the strains of Cordyceps cicadae conducted the following research to obtain higher safety of flocculant-producing strain resources,and analyze the various properties of microbial flocculant and influencing factors.of its application.Screened a stable and high producing strain GZUIFR-6722 from 36 strains Cordyceps cicadae conserved in the Insititute of fungal resource,Guizhou University.And studied on the relationship between flocculant-producing capacity with genetic and geographical in 36 strains Cordyceps cicadae.The results showed that there was some correlations between the flocculation properties and collection locations of 36 strains Cordyceps cicadae.The flocculation rate of strains fermentation broth from Mount Qingcheng and Mount Emei,Sichuan province,were higher than 50%,but the flocculation rate which strains from Jeju Island,South Korea were less than 41%.There was great difference between 6 strains Cordyceps cicadae which came from sink holes group,Leye country,Guangxi.However,it was no necessary connection between the flocculation properties with its three genes which were ITS,EF1 a,and ?-tublin in 36 strains Cordyceps cicadae.The pH of fermentation broth declined firstly and then stabilized with the growth of the strain GZUIFR-6722,and there was positive correlation between accumulation of biomass and microbial flocculant produced of the strain.The flocculating activity substances of GZUIFR-6722 were primarily extracellular polysaccharide which accounted for 91% of extracellular extracts.To optimize the conditions,the flocculant GZUIFR-6722 treated on the kaolin suspension.The results showed that the best conditions were addition of 2.0 mL/50 mL bioflocculant,2.5% CaCl2,pH 4 which was kaolin suspension,30?,after 25 reversal turns and standing for 20 min.In this work,we found that the optimum conditions were different between single factor and orthogonal experiment.It probably was the instabilities in the application of microbial flocculant,and this instabilities caused difference which was under the interaction of various factors.This work optimizated the medium component and conditions of the strain GZUIFR-6722,using the single factor and orthogonal experiment to improve the production of the bioflocculant,.The results showed that sucrose was the optimum carbon source,beef extract was the optimum nitrogen source.And the orthogonal experiment showed the optimum medium and conditions were 25 g/L sucrose,3 g/L beef extract,2 g/L KH2PO4,0.5 g/L MgSO4·7H2O,0.5 g/L CaCl2.Initial medium pH was 6,Inoculating 1 mL spore suspension which concentrations was 1×107/mL.Bottle volume was 200 mL/500 mL,cultured 7 days at 25? and 140 rpm/min.Bioflocculant GZUIFR-6722 was applied for the coal washing waste water which was produced coal preparation industry with ecological treatments.The result showed that bioflocculant GZUIFR-6722 had a better flocculation effect on coal washing waste water,and the optimum conditions were addition of 1.2 mL/50 mL bioflocculant,adding 2% CaCl2 1 mL,after 5 reversal turns and standing for 5min.And then,the flocculating rate was(94.02±1.23)%.Compared the bioflocculant GZUIFR-6722 with PAM which is used in industry.The results showed that the bioflocculant GZUIFR-6722 had a higher ability of flocculation,but it was large dosage compared to PAM.In conclusion,Cordyceps cicadae bioflocculant which was high security has large application foreground.