Biodegradation Potential of White Rot Fungus in Waste Tire Rubber

Abstract

Vehicle tires are high demand inputs in the transportation sector, however, at the end of their useful life they become a technical, economic, environmental and public health problem, due to their complex structure made up of various materials, especially vulcanized rubber. One possible way to mitigate the environmental impact of waste tires is to biodegrade rubber through the enzymatic action of fungi. The present study evaluated the biodegradation potential of waste rubber tires by enzymatic action of a white rot fungus (Pleurotus Ostreatus). Initially, the effect of the enzymatic action of the fungus on the mechanical structural and chemical properties of the rubber was evaluated. Sterilized tire rubber cuts of 1 cm2 were innoculated with the fungus. After 16 and 40 days, surface changes were evaluated by environmental scanning electron microscopy (ESEM). It was detected that the enzymatic action on the molecular bonds caused material erosion; changes in chemical structure by Fourier transform infrared spectroscopy (FTIR) were evaluated after 40 days. Also, potential of the scrap tire material to produce fungi biomass was analyzed, by preparing different concentrations of pulverized waste tire material in Agar Sabourad, and innoculating them with a suspension of the fungus mycelia. After 21 days, the germinated biomass at each substrate concentration was gravimetrically analyzed and modeled. Results showed a proportional dependence of the biomass growth as a function of the substrate concentration, and a potential of the white rot fungus to help biodegradation of waste tires.