Abstract:
Microplastics (MPs) have significantly increased in natural habitats as a result of the
extensive use and mismanagement of plastic items. MPs are persistent in nature and therefore
are to degradation. However, some microorganisms have the ability to enzymatically
breakdown them. This study focuses on the in-silico identification, characterization, and
molecular docking analysis of different lipases and polygalacturonases found in various
fungal species, specifically aiming to assess their potential for microplastic degradation. A
total of 71 lipases and 96 polygalacturonases were identified from 13 and 10 fungal species
respectively, on the basis of presence of the lipase 3 and glycoside hydrolase 28 domain. Most
of the proteins were predicted to be extracellularly localized. Based on the results of
molecular dockings, in terms of binding affinities, all the proteins were found to have high
binding affinity towards PC, which suggests that it is the most biodegradable plastic type.
However, PVC exhibited low binding energies with both lipases and polygalacturonases,
indicating its resistance against degradation via fungal enzymes. Key amino acids primarily
involved in binding interactions of polycarbonate (PC) were found to be alanine, glycine, and
valine. The binding interactions encompass hydrogen bonding, van der Waals forces and Pi interactions. These findings highlighted the potential of enzymes sourced from fungal species
for microplastic degradation purposes. Furthermore, the results of the in vitro experiment
revealed that A. flavus exhibited limited growth on PVC, and lipase production remained
minimal. Additionally, no discernible change in weight was observed in the PVC film after
incubation with A. flavus.
