Biodegradation of PVCs through in-vitro identification of Bacillus albus and computational pathway analysis of ABH enzyme

Marine microalgae - Mediated biodegradation of polystyrene microplastics: Insights from enzymatic and molecular docking studies

Biodegradation of microplastics (MPs) through microalgal strains would be of eco-friendly approach for significant pollution abatement. Polystyrene (PS) is a major contaminant in the marine environment; however studies on marine microalgal degradation of PS MPs have been very limited. In the present study, six marine microalgal strains viz. Picochlorum maculatum, Dunaliella salina, Amphora sp., Navicula sp., Synechocystis sp. and Limnospira indica were investigated for their ability to degrade PS MPs for the incubation period of 45 days. Results from weight reduction, ATR-FTIR, SEM, and molecular docking analysis confirmed that microalgae formed biofilms on PS MPs, causing structural changes, and laccase-driven enzymatic breakdown. A maximum weight loss of 23.2 ± 0.21% and a minimum of 11.3 ± 0.026% were caused by the colonized microalgae Synechocystis sp. and Amphora sp. respectively. The study indicated that a higher reduction rate was observed in the Synechocystis sp. Treated PS MPs with a rate of 0.0058 g/day and a lower half-life of 119.34 days. SEM analysis showed that microalgae caused pits, erosion, and damage to the PS film. ATR-FTIR confirmed the chemical modifications and proved biodegradation. Laccase enzyme activity was higher in Synechocystis sp., and molecular docking showed the laccase interaction with the derivatives of PS, elucidating the breakdown process. This study highlights the potential of microalgae for eco-friendly microplastic degradation and paves the way for future research on the by-products of this process. Exploring the ecological impact of by-products and optimizing scalable methods can further enhance the sustainability and practical applications of this promising solution.

Comparative analysis among the degradation potential of enzymes obtained from Escherichia coli against the toxicity of sulfur dyes through molecular docking

The common bacterium Escherichia coli has demonstrated potential in the field of biodegradation. E. coli is naturally capable of biodegradation because it carries a variety of enzymes that are essential for the breakdown of different substances. The degradation process is effectively catalyzed by these enzymes. The collaborative effects of E. coli's aryl sulfotransferase, alkanesulfonate moonoxygenase, and azoreductase enzymes on the breakdown of sulfur dyes from industrial effluents are investigated in this work. ExPASY ProtParam was used to confirm the stability of the enzyme, showing an instability index less than 40. We determined the maximum binding affinities of these enzymes with sulfur dye pollutants - 1-naphthalenesulfonic acid, sulfogene, sulfur green 3, sulfur red 6, sulfur red 1, sulfur yellow 2, thianthrene, thiazone, and thional - using comparative molecular docking. Significantly, the highest binding affinity was shown by monooxygenase (-12.1), whereas aryl sulfotransferase and azoreductase demonstrated significant energies of -11.8 and -11.4, respectively. The interactions between proteins and ligands in the docked complexes were examined. To evaluate their combined effects, co-expression analysis of genes and enzyme bioengineering were carried out. Using aryl sulfotransferase, alkanesulfonate monooxygenase, and azoreductase, this study investigates the enzymatic degradation of sulfur dye pollutants, thereby promoting environmentally friendly and effective sulfur dye pollutant management.