Biodegradation of gamma irradiated low density polyethylene and polypropylene by endophytic fungi

• The exposure to Gamma irradiation resulted in weakening the bonds which facilitated the endophytic fungi to colonize the polymer.
• Endophytic fungi inoculated on Gamma irradiated LDPE strips exhibited promising biodegradation pattern.
• Laccase producing Lasiodiplodia theobromae degraded irradiated polypropylene film with 0.3 mg on actual weight loss basis.

Biodegradation of plastic waste through fungal strains offer a solution to serious issues of pollution as fungi are known to release plastic degrading enzymes. In the present study, the isolated endophytic fungi from two endemic plants, Psychotria flavida and Humboldtia brunonis which produced laccase enzymes and grew profusely over hydrophobic surface of plastic films were tested for biodegrading ability. The fungi were inoculated on the polythene and polypropylene films irradiated with different doses of radiation, (0–1000 kGy for Low Density Polyethylene and 0–100 kGy for Polypropylene) and incubated for 90 days. The extent of biodegradation pattern of endophytic fungi was measured for the highest dose mainly by analyzing changes using FTIR spectroscopy, DSC, SEM, alteration in viscosity and thereby average molecular weight. The decrease in intrinsic viscosity and average molecular weight of gamma irradiated LDPE strips inoculated with Aspergillus sp., Paecilomyces lilacinus from H. brunonis and Lasiodiplodia theobromae from Psychotria flavida indicate fungal efficiency in plastic degradation. Only L. theobromae from P. flavida could degrade irradiated polypropylene film with 0.3 mg on actual weight loss basis. Further work on employing these endophytic fungi in biodegradation of plastics is warranted.