Vol. 126 No. 2
April – June

Isolation of Decomposer Fungi with Plastic Degrading Ability

Virginia C. Cuevas and Rodolfo Managilod

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.