Molecular characterization and molecular docking of xylanase produced by novel species Bacillus aryabhattai isolated from mangrove soil and its biodegradation efficiency

Abstract

Xylanase-producing bacteria play a crucial role in the degradation of lignocellulosic biomass, facilitating the breakdown of xylan into xylooligosaccharides and xylose. This study aimed to isolate and characterize xylanase-producing bacteria from mangrove ecosystems in Cuddalore and Pondicherry, India. A total of 22 bacterial isolates were obtained, out of which five (PMS1, PMS8, PYMW, SBMS4, and SBW1) exhibited significant xylanolytic activity. Molecular characterization using 16S rRNA sequencing identified these isolates as belonging to the Bacillus genus, with Bacillus aryabhattai (PYMW) and Bacillus subtilis (PMS8) demonstrating the highest xylanase activity. Optimization studies revealed that enzyme production peaked at pH 8.0, with maltose and glucose serving as the most effective carbon sources, and yeast extract enhancing enzyme yield (4.1 ± 0.2 U/mL) and (3.2 ± 0.2 U/mL) respectively. The xylanase enzyme was purified using ammonium sulfate precipitation, yielding a molecular weight of 50 kDa as confirmed by SDS-PAGE. Further, immobilization using sodium alginate beads enhanced enzyme stability and reusability, making it a viable candidate for industrial applications. Molecular docking studies provided insights into enzyme-substrate interactions, highlighting key residues involved in xylan degradation. These findings underscore the potential of mangrove-derived Bacillus strains as sustainable sources of xylanase for applications in bioethanol production, paper manufacturing, and waste management. Future research should focus on large-scale production, genetic modifications for enhanced efficiency, and industrial applications of immobilized xylanase.