Degradative impact of Alternaria multiformis on novel polymeric biocomposites with the fillers of industrial waste materials under different pH and temperature conditions

Abstract

The impact of Alternaria multiformis on novel polymeric biocomposites formed from epoxidized linseed oil and various types of fillers: pine needles (PN), pine bark (PB), grain mill waste (GW), rapeseed cake (RC) and specimen without filler (WF) under different pH and temperature conditions has been studied. Identification of fungal strain A. multiformis 0065 isolated from synthetic polymer was based on molecular and morphological analysis. Tested fungal strain showed significant production of polyphenol oxidase and weak production of amylase, endoglucanase, xylanase, and lipase. Polymeric biocomposites PB, GW, RC, and WF exposed to A. multiformis for four weeks showed the greatest weight loss at pH 4 or pH 5 and at a temperature of 26 °C, suggesting the optimal conditions for biodegradation of polymeric biocomposites studied. The attenuated total reflectance infrared spectroscopy (ATR-IR) and scanning electron microscopy (SEM) analysis confirmed biodegradation of polymeric biocomposites after fungal attack. ATR-IR technique revealed changes in the intensities of the signals, demonstrating dependence of degradation on the type of the filler. SEM analysis showed significant alterations of the specimen surfaces, indicating degradative impact of A. multiformis. Identification of the most biodegraded constituents could help in the creation of more environmentally friendly biocomposites.