Production Technology Of Bioflocculant Using Bioflocculant-producing Bacteria Immobilized By Mycelial Pellets

As for its high safety, innocuity, no second pollution, wide application rangeand low cost, bioflocculant will be widely used instead of conventional chemicalflocculant. The single fermentation technology and high production cost havebecome the bottleneck of its wide application. This dissertatioin combinedbioflocculant production with immobilized fermentation, and mainly studiesselection of immobilization carriers, immobilized by mycelia pellets fermentationcondition optimization and periodic monitoring in BF110modular fermentor,thestability of semi-continuous production of bioflocculant immobilized by myceliapellets and dissolved oxygen control, which accelerated the bioflocculantimmobilized fermentation production steps and laid the foundations for thebioflocculant industrial production.The performance of the carriers including activated carbon, pllyurethane foam,and mycelial pellets was contrasted by comparing the carrier stability,bio-flocculant production and bio-flocculant activity. The solid-liquid ratio ofactivated carbon and mycelial pellets were optimized. The results showed that underthe optimized conditions (solid-liquid ratio1.0g/L; the fermentation time24h), thecrude bio-flocculant yield of immobilized fermentation by granular activated carbonwas2.18g/L. The shake flask experiments showed that granular activated carboncould produce bioflocculant more than15days. The mycelia pellets is a highperformance immobilized carrier. The result of the adsorption experiment of strainF+indicated that the adsorption rate of mycelial pellets in24h was higher than thatof granular activated carbon. Under the optimized conditions (solid-liquid ratio1.0g/L; the fermentation time24h), the crude bio-flocculant yield of immobilizedfermentation by mycelial pellets (2.23g/L) increased14%. The shake flaskexperiments showed that the three carriers could produce bioflocculant more than15days.The fermentation conditions of mycelia pellet immobilized strain F+producingbioflocculant were optimized by orthogonal experiment. The results showed theoptimal fermentation conditions were as follow:33℃，stirring speed at150r/min,aeration rate of2.5L/min, fermentation time of24h;This paper monitored bacterium turbidity, pH, polysaccharide, DO,TN and TP during the fermentation procession.The results indicated that DO, TP, glucose and other parameters had a large changeduring fermentation procession.The mycelia pellet real lifetimes in fermentation tank was5days. In theseventh generation of mycelial pellet, it could adsorp strain F+although themycelial pellet had been borken. and mechanical stirring had a large influence onmycelia pellet structure. The dissolved oxygen was one of the limits of furtherimprovement of bioflocculant, and improving the mechanical stirring speed wasused to improve the bioflocculant production to2.54g/L.