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

Abstract

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.

Production, Characterization, and Flocculation Mechanism of Cation Independent, pH Tolerant, and Thermally Stable Bioflocculant from Enterobacter sp. ETH-2

“…BY-29 [23] , Enterobacter cloacae WD7 [20] , Enterobacter sp. EP3 [24] and Enterobacter aerogenes [4] , have been isolated and their producing bioflocculant characterized.…”

“…Calcium chloride produced a synergistic effect on kaolin flocculation for bioflocculant produced by Enterobacter cloacae WD7 [20] and Enterobacter sp. EP3 [24] . However, trivalent cations possibly alter the surface charge of kaolin particles and cover the adsorb sites [38] .…”

A novel thermally stable heteropolysaccharide-based bioflocculant from hydrocarbonoclastic strain Kocuria rosea BU22S and its application in dye removal

“…6D that divalent cations (Mg 2+ , Ca 2+ and Fe 2+ ) were more effective than monovalent (Na + and K + ) and trivalent cations (Fe 3+ and Al 3+ ). The role of bivalent cations is to increase the initial adsorption of pKr on kaolin by decreasing the negative charge on both bioflocculant and particle [66][67][68]. However, the flocculating rate decreased by approximately 15%…”

“…These results suggest that pKr was more effective for anionic dyes than cationic dyes. Similarly, the bioflocculant produced by A. parasiticus was effective for the removal of anionic dyes [68]. Conversely, the bioflocculant produced by P. elgii possesses functional groups that have the ability to decolourize cationic dyes in wastewater.…”