Studying Of The Characterization Of Bioflocculant Production By Klebsiella Sp. NIII2and Its Mutant Strains

Bioflocculant has great potential in water and wastewater treatment process for itsgreen solid-liquid separation. The low production and high production costs limit itsapplication. It has practical significance that improve bioflocculant production andappy it in industrial production.In this paper, the optimization of fermentation conditions for high yieldbioflocculant and its characteristics of bioflocculant production by Klebsiella sp. NIII2and its mutant strains NIII2-1、NIII2-2were studied by IR, Zeta potential measurement,particle size distribution, DR5000and other research tools. It obtains the followingresults from the study.(1) A high yield bioflocculant mutant strain NIII2-2has been obtained by LiClinduced mutation from Kebsiella sp.NIII2. And, B vitamins could increase theproduction of bioflocculant by Klebsiella sp. NIII2and its mutant strains NIII2-1、NIII2-2. Its optimum fermentation culture were: the seeds of pH9.0, the fermentationculture of pH7.5, the Mg2+concentration of0.7mmol/L.(2) The Mg2+impacts the characteristics of bioflocculant production by Klebsiellasp. NIII2and its mutant strains NIII2-1、NIII2-2. The bioflocculant production wasimproved by adding0.5-0.7mmol/L Mg2+. Bioflocculant yields could reach9.7g/L.The yellowish substrate which can be as a sign of high bioflocculant yield could beobserved and also that little acidic compounds which resulted in the final pH values ofculture below7.0were secreted, compared with the fermentation culture were withoutor with small amount of Mg2+added. The concentration of Mg2+in fermentationculture also influenced the composition of bioflocculant produced. The proteincontents improved24%,63.3%,25%and the Zeta potential of bioflocculant produced Klebsiella sp. NIII2and its mutant strains NIII2-1、NIII2-2under conditions with lageramount of Mg2+(0.7mmol/L) in culture fluid were high and the ratios of flocculantwere improved.(3) The bioflocculants production by Klebsiella sp. NIII2and its mutant strainsNIII2-1、NIII2-2were glycoprotein. The more protein content, the greater activity. Itsactivity could be decreased for the inactivation of protein by urea.