Selection and characterization of ligninolytic Bacillus albus PA3/3 from fermented tea leaf and its use in industrial wastewater treatment

Lignin and lignin-related compounds are considered complex barrier substrates that are difficult for microorganisms to degrade. Therefore, the search for potential novel ligninolytic bacteria has become a focus in the field of biotechnology with the aim of making the process easy, effective, environmentally friendly and cost- effective. In this study, the ligninolytic Bacillus albus PA3/3 was isolated from lignin-containing fermented tea leaves, using guaiacol as a substrate, and identified based on 16S rRNA gene sequencing and phenotypic characterization. Bio-decolorization activities in synthetic dye and wastewater treatment were also determined. The results revealed that B. albus PA3/3 is a Gram-positive bacterium with 99.35 percent sequence identity to B. albus. The strain PA3/3 decolorized methylene blue and showed oxidative activity towards guaiacol, as a lignin- mimicking compound. B. albus strain PA3/3 produced laccase with peroxidase and extracellular xylanase, amylase, and protease. Moreover, strain PA3/3 showed dye-decolorization properties with a particular preference for the recalcitrant azo dye (Reactive Black 5, Reactive Green 19 and Reactive Red 120). These bacteria were used to treat textile and ink industry wastewater. The results demonstrate the potential of B. albus PA3/3 as a promising tool for decolorization and industrial wastewater bio-treatment.