Bacterial ligninolytic enzymes and their applications in bioremediation

Bacterial ligninolytic enzymes demonstrate high stability and catalytic efficiency across a wide range of environmental conditions, with production strongly influenced by strain-specific and process parameters. Enzyme yields vary significantly depending on the fermentation strategy, with solid-state fermentation (SSF) consistently producing higher activities than submerged fermentation (SmF) due to enhanced substrate-microbe interactions and stronger induction by lignocellulosic materials. In contrast, SmF provides improved control over pH, temperature, and aeration, enabling greater process reproducibility and scalability despite comparatively lower enzyme yields. Comparative analysis further indicates that enzyme production is highly strain-dependent and influenced by environmental parameters, including pH, temperature, substrate type, and incubation time. Among bacterial genera, Bacillus, Streptomyces, Acinetobacter, and Micrococcus exhibit consistently high enzyme production, with certain strains showing significantly elevated manganese peroxidase (MnP) and lignin peroxidase (LiP) activities under optimized conditions. Xenobiotic compounds, including synthetic dyes, pesticides, and Maillard reaction products, act as both substrates and inducers, stimulating enzyme production through oxidative stress-mediated pathways. Reactive oxygen species generated during pollutant exposure enhance the expression of bacterial ligninolytic enzymes, while structural similarities between xenobiotics and lignin-derived compounds facilitate their degradation. Sequential enzyme activity is observed, with MnP initiating early-stage oxidation followed by laccase-mediated transformation, indicating synergistic degradation mechanisms. Bacterial ligninolytic enzymes achieve degradation efficiencies exceeding 90% for a wide range of pollutants, including dyes, pesticides, and plastic-associated compounds. Spectroscopic and chromatographic analyses (UV-Vis, FT-IR, GC-MS, and LC-MS) confirm the conversion of complex aromatic compounds into simpler, less toxic intermediates. The integration of advanced omics-based approaches, including metagenomics, metatranscriptomics, and metaproteomics, is increasingly recognized as a powerful strategy for the discovery and functional characterization of novel ligninolytic bacteria and their enzymes. These findings demonstrate that bacterial ligninolytic enzymes are efficient and robust systems for pollutant degradation and lignin valorization, with strong potential for large-scale biotechnological applications.

The online version contains supplementary material available at 10.1007/s13205-026-04859-z.