Isolation of functional ligninolytic Bacillus aryabhattai from paper mill sludge and its lignin degradation potential

Abstract

Kraft lignin (KL), is the major pollutant in pulp and paper effluent and due to its heterogeneous structure, it is resistant to the depolymerization process. It has drawn much attention from the researcher due to its challenging degradation process. In this study, a KL-degrading bacterium was isolated and screened from paper mill sludge. This bacterium was identified as ligninolytic Bacillus aryabhattai using biochemical and 16SrRNA gene analysis. B. aryabhattai showed maximum activities of lignin peroxidase-LiP (0.74 IU mL−1) and manganese peroxidase-MnP (9.2 IU mL−1) on the 4th day, and 5th day, respectively. A total 84% of KL (500 mg L−1) reduction was observed after 14 days. The KL bio-degradation was confirmed based on changes in chemical stracture of KL and new metabolites identification using FTIR and GC–MS, respectively. The study concluded that B. aryabhattai maybe becomes a potential biological agent in KL biodegradation and treatment of other lignin-containing industrial effluents.

Keywords

• Kraft lignin
• Bacillus aryabhattai
• Biodegradation
• SEM
• FTIR
• GC–MS