Pioneering PVA-degrading microorganism Burkholderia contaminans DW01: microbial characteristics, metabolic strategy, and biodegradation mechanism.

Abstract

A Polyvinyl Alcohol (PVA) degrading bacterial strain designated as DW01, was isolated from textile wastewater. Based on 16S rRNA gene sequence analysis (carried out at the EzTaxon server and Ribosomal Database project site), DW01 was identified as Burkholderia contaminans, and its biological characteristics, biodegradation performance, metabolic strategy, and molecular mechanisms were investigated. Haldane kinetic analysis revealed a substrate inhibition pattern, with optimal PVA concentrations of 2.31 g·L^-1 for growth and 2.83 g·L^-1 for biodegradation. Under sole PVA conditions, DW01 adopts a "growth-first, biodegradation-secondary" strategy. Multi-spectroscopic analyses elucidated the PVA biodegradation pathway and its molecular constraints. DW01 acts as a pioneer by cleaving the PVA main chain and generating carbonyl and carboxylic acid intermediates. XRD and ¹H NMR revealed the constraints on efficiency: DW01 exhibits stereochemical preference for syndiotactic PVA segments, while isotactic and heterotactic segments are recalcitrant, constituting the molecular bottleneck limiting efficiency; thus, a new mechanism was proposed. The study first reports PVA-degrading capability within Burkholderia, elucidates its "growth-first" metabolic strategy, biodegradation mechanism, and tacticity-dependent bottleneck, providing microbial resources and theoretical guidance for PVA control. Construction of "pioneer-terminator" consortia via metabolic complementarity and stereochemistry-targeted enzyme engineering are two priority directions to achieve complete PVA mineralization in future research.