Production and Characteristics of a Bioflocculant by Klebsiella pneumoniae YZ-6 Isolated from Human Saliva

The production and characterization of a bioflocculant, MBF-6, by Klebsiella pneumoniae was investigated. Optimum culture conditions for bioflocculant production were an initial medium pH of 7, an incubation temperature of 30 °C, and an inoculum size of 1 % (v/v) of cell density 1.0 × 108 cfu/mL. The carbon, nitrogen, and cation sources for optimum bioflocculant production were glucose, peptone, and ZnCl2. The bioflocculant mainly consisted of protein (3.4 %) and sugar (95.1 %). Fourier transform infrared (FTIR) spectrum revealed the presence of carboxyl and hydroxyl groups while the thermogravimetric analysis (TGA) showed a degradation temperature (T d) of 81.4 °C. MBF-6 had a good flocculating rate in kaolin suspension without cation addition and was stable over a wide range of pH and temperature. Investigation on the flocculation efficacy of the characterized MBF-6 for wastewater treatment of dairy, woolen, brewery, and sugar industries suggested it to be effective.