Characteristics and Flocculating Mechanism of a Bioflocculant M-1 Produced by Enterobacter sp. EP3

A bioflocculant M-1 produced by Enterobacter sp. EP3 was investigated with regard to its flocculanting characteristics and mechanism. 2.0 mg/l M-1 showed the maximum flocculating activity of 96% in 5.0g/l Kaolin suspension containing 8mM CaCl2 and that its flocculating activity was more than 80% in a wide pH range (4.0-12.0). Chemical analyses indicated that the biopolymer M-1 was mainly a polysaccharide, mainly consist of rhamnose and glucose with a molar ratio of 9:1. Infrared spectrophotometry showed the presence of carboxyl, hydroxyl and methoxyl groups in M-1 molecular. Flocculation of Kaolin suspension with M-1 acted as a model to explore the flocculating mechanism in which bridging mediated by Ca2+ was proposed as the primary action based on the experimental observations.