Decolorization and Degradation of Kraft Lignin Discharged from Pulp and Paper Mill Industry by Axenic and Co-Culture of Bacillus sp.

Abstract

The aromatic 3-D polymer Lignin, one of the major plant/lignocellulosic biomass, is composed of potentially valuable phenolics monomers (Coumaryl, Guaicyl, Syringyl). Currently lignin and its colloidal solution in water, black liquor, obtained as by-products in many biomass treatment processes, e.g., pulping in paper industry, remain to be considered recalcitrant substrates of a limited commercial value. In developing countries, Kraft lignin (KL) containing Black liquor generated from pulp and paper mill waste water causes severe environmental pollution. This study presents the recent research on bacterial kraft lignin degradation. Kraft lignin degrading bacterium was isolated from the environment of a timber area and further identified by biochemical and 16s rRNA sequencing as Bacillus subtilis. Data of this study revealed that this bacterium reduced lignin (18.66%) and decolorize (25.07%) maximum at 168 h of incubation in axenic condition while in co-culture condition reduced lignin content was reduced to (38%) and 847mg /L (42.89%) respectively. This strain can play key role in remediation of pulp and paper mill effluent as well as degrading material for chemical and biofuel production.