Bioremediation of Simulated Textile Effluent by an Efficient Bio-catalyst Purified from a Novel Pseudomonas fluorescence LiP-RL5

Abstract

Background: Microbial degradation of highly stable textile dyes, using lignin peroxidase, is an eco-friendly, less expensive and much advantageous in comparison to the chemical method. Objective: Biodegradation potential of lignin peroxidase (LiP), from Pseudomonas fluorescens LiP-RL5, was enhanced after optimization and purification so as to use it as a potential bioresource for the treatment of textile effluent. Methods: LiP producing bacterial isolate was primarily screened by methylene blue assay followed by LiP assay. The standard protocol was used for purification of lignin peroxidase and purified LiP was finally used for degradation of textile dyes. Results: 57 bacterial isolates were screened for lignin peroxidase activity. Isolate LiP-RL5 showed maximum activity (19.8 ±0.33 %) in terms of methylene blue reduction in comparison to others. Biochemical and molecular characterization of LiP-RL5 showed 99 % similarity with P. fluorescens. Lignin peroxidase activity was increased by 50 % after optimization of cultural conditions. Maximum enhancement in the activity was achieved when peptone was used as a nitrogen source. LiP from P. fluorescens LiP-RL5 was further purified up to 2 folds. SDS-PAGE analysis revealed a single protein band of approximately 40 kDa. Enzyme also showed high catalytic efficiency with Km= 6.94 mM and Vmax= 78.74 μmol/ml/min. Purified enzyme was able to decolorize the simulated textile effluent up to 45.05 ±0.28 % after 40 minutes. Conclusion: : High catalytic efficiency of purified LiP from P. fluorescens LiP-RL5 suggests its utility as a potential candidate for biodegradation of toxic dyes in the industrial effluent, which could be successfully utilized for wastewater treatment at commercial level.