Enhancement of fungal degradation of starch based plastic polymer by laser-induced plasma

Abstract

Fourteen fungal species (Alternaria alternata, Aspergillus candidus, Aspergillus flavus, Aspergillus niger, Aspergillus ochrochus, Botrytis cinerea, Chaetomium globosum, Fusarium moniliforme, Fusarium oxysporum, Fusarium solani, Penicillium chrysogenum, Penicillium funiculosm, Penicillium italicum and Phanerochaete chrysosporium) belonging to Ascomycete, Basidiomycete and Deuteromycete groups were isolated from composted soil in Egypt. The ability of laser induced plasma as a new technique to enhance fungal degradation efficiency of starch based plastic polymer was tested. The maximum significant plastic degradation activities for all isolated fungal species were showed after the lowest exposure time (5 min) to laser induced plasma. The highest efficient fungal degraded starch based plastic polymer was A. niger, where the initial appearance of clear zone was recorded only after two days accompanied with the highest significant amylotic activities. The evaluation of changes in starch based plastic polymer degraded by A. niger compared with uninoculated and non plasma treated A. niger degraded starch based plastic polymer was observed by scanning electron microscope (SEM). The maximum degradation efficiency accompanied with the highest loss of tensile strength (90 and 80.7%, respectively) was observed in the plasma treated A. niger degrading starch polymer. Four low molecular weight sugars were detected by HPLC in plasma and non plasma treated A. niger degrading plastic polymer.