title: Culture conditions for flocculant production by Paenibacillus polymyxa BY-28.
abstract: A new flocculant-producing bacterium Paenibacillus polymyxa BY-28 was isolated from soil. The optimal culture media for flocculant production were 2% glucose, 0.3% KH2PO4, 0.1% bean cake powder, 0.05% CaC12 and 0.05% (w/v) MgSO4.7H2O. Optimal culture temperature was 30 degrees C and pH was 6-8. Flocculants produced under optimal conditions efficiently aggregated various organic and inorganic suspensions in simulated water as well as in wastewater by addition of bivalent and trivalent cations Ca2+. From Zeta-potential measurement, the dominant role of microbial flocculant in the flocculation process is based on the bridging mechanism, and the role of CaCl2 is to decrease the negative electrical charge of the Kaolin clay particles.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China. xiaoyan_gong@sina.com.cn
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Gong
authors.forename: Zhao-Kun
authors.initials: ZK
authors.lastname: Luan
authors.forename: Yuan-Sheng
authors.initials: YS
authors.lastname: Pei
authors.forename: Shu-Guang
authors.initials: SG
authors.lastname: Wang
mesh_terms: D000538:Aluminum Silicates; D001419:Bacteria; D000077215:Clay; D003470:Culture Media; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D000538:Aluminum Silicates; D003470:Culture Media; D000077215:Clay