Isolation and Characterization of Melanoidins Degrading Bacteria from Sugar-Mill Effluent

Abstract

Melanoidins are major coloring and polluting constituents in distillery wastewaters which have caused substantial environmental pollution in Bangladesh. Hence, this study was designed for isolation and characterization of melanoidins degrading bacteria from sugar-mill effluent. A total of five melanoidins degrading bacteria viz. Z1, Z2, Z3, Z4 and Z5were isolated from sugar-mill effluent and identifiedas Exiguobacteriumacetylicum strain QD-3,Bacillus cereus strain H3, Enterobacter sp. PR1, Pseudomonasaeruginosa strain AU09 and Bacillusmegaterium strain Jz11 by biochemical tests and 16S rRNA gene sequence analysis. The isolates were tested for Chmeical Oxygen Demand (COD) and colour removal ability. The highest reduction of COD (93%) and removal of colour (60%) were obtained by the treatment with bacterial isolateBacillus cereus strain H3. Spectrophotometric and COD analyses of treated effluent demonstrated that decrease in colour intensity might be largely attributed to the degradation of melanoidins by isolated bacteria.