Biodegradation of Two Synthetic Polyesters (PCL, BTA) under Salt Stress

Abstract

The target of this study was to isolate fungal strains from saline environments able to degrade two synthetic polyesters (PCL, poly (-ɛ-caprolactone) and adipic acid (1, 4-butanediol, terephthalic-adipic, BTA).The clear zone method on mineral salt yeast extract medium (MSY) containing polymers was adopted to compare the degradative efficacy of isolated fungi. Scanning electron microscope as well was used to examine polymer degradation by Aspergillus flavus. Through this study a total of 22 fungal strains were isolated and identified as members of the genera Aspergillus, Acremonium, Cladosporium and Penicillium. The results indicate that isolated fungi can be divided into several groups according to their response to additional carbon and/or nitrogen sources such as glucose, peptone, casein, and others which led to an increase in the radial growth and hence an increased clear zone diameter. Scanning Electron micrographs of Aspergillus flavus confirmed the results of weight loss and exposed the presence of fungal growth on PCL-S MATER Bi ZF03U films. The film surfaces exposed to the fungal strains had a rough appearance visibly different from that of the control. The surface of the films possessed numerous pits depths of varying sizes. The fungal mycelium growing on and invading the polyester material thereby cracking the film surface was also obvious. The findings of this research may contribute to realize the role of fungi in biodegradation of non-degradable synthetic polymers.