Grzegorz Janusz

In the 21st century, humans are facing a high risk of exposure to emerging pollutants. Water contamination has become a major threat due to its devastating impacts on the entire ecosystem. Relatively great danger for aquatic microorganisms is posed by organic micropollutants, which are a consequence of progressing urbanization and industrialization. This review focuses on laccase of mainly fungal and bacterial origin, which provides an eco-friendly strategy for the transformation of these harmful pollutants to less or non-toxic compounds, as it acts oxidatively on the aromatic ring of a wide range of compounds, releasing water as the only by-product. Laccase alone or with the use of mediators has been used successfully to remove micropollutants from wastewater, including pharmaceuticals and personal care products, biocides, endocrine disrupting agents, steroid hormones, and microplastics. Even though the potential of an LMS (laccase–mediator system) is tremendous, the selection of an appropriate mediator and the persistent monitoring of toxicity after treatment are critical and should be performed routinely. Hence, further research is still needed for the optimization of degradation processes to improve our understanding of the different interactions of laccase with the substrate and to develop sustainable advanced water treatment systems.

Deadwood plays an important role in forest ecology; its degradation and, therefore, carbon assimilation is carried out by fungi and bacteria. To quantify the abundance and distribution of microbial taxa inhabiting dead spruce logs fallen over a span of 50 years and the soil beneath, we used taxonomic profiling with NGS sequencing of hypervariable DNA fragments of ITS1 and 16S V3-V4, respectively. The analysis of sequencing data revealed a high level of diversity in microbial communities participating in the degradation of spruce logs. Differences in the relative abundance of microbial taxa between the samples of the wood that died in 1974 and 2014, and of the soil in its immediate vicinity, were visible, especially at the genus level. Based on the Lefse analysis significantly higher numbers of classified bacterial taxa were observed in the wood and soil samples from 2014 (wood: 1974-18 and 2014-28 taxa; soil: 1974-8 and 2014-41 taxa) while the number of classified fungal taxa was significantly higher in the wood and soil samples from 1974 (wood: 1974-17 and 2014-9 taxa; soil: 1974-57 and 2014-28 taxa). Most of the bacterial and fungal amplicon sequence variants (ASVs) unique to wood were found in the samples from 1974, while those unique to soil were detected in the samples from 2014. The ATR-FTIR method supported by CHN analysis revealed physicochemical changes in deadwood induced by the activity of fungal and bacterial organisms.