Isolation of decomposer fungi with plastic degrading ability 6

ABSTRACT : A study was conducted to isolate from natural environment decomposer fungi that has the capability to degrade plastic sheets. The isolates will be used as component of new mixed fungal inocula from rapid composting of market wastes. Rate of decomposition of four different types of plastic bags in the natural environment was also determined by measuring their loss in weight with time. Mean half-life of plastic bags was computed. Ordinary polyethylene sando plastic bags commonly used as containers of consumer goods in dry goods stores and wet markets were buried 2 cm deep on the forest floor. Each sample was cut two sides and converted into flat sheet before burying. At regular monthly intervals the plastic sheets were retrieved, cleaned of adhering soil particles and artifacts and plated in coconut water agar. Fungi growing on the plates were isolated and identified. Plastic degrading capability of the isolates were tested by growing them in mineral medium where plastic strips were used as main source of carbon. Assessment of the plastic degradation was measured in terms of loss in weight of the plastic strips and by the amount of mycelia produced by the fungal isolates. There were four species microfungi found growing on the plastic sheets. They were two species of Penicillium, one species of Aspergillus and sterile mycelia belonging to Ascomycete Xylariales group. Only Ascomycete mycelia developed good growth in all the treatments with only plastic strips as source of carbon. This isolate also caused decreases in weights of the plastic strips in these treatments This isolate is now a component of the fungal inocula being pilot tested for composting market wastes. 56

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