The Biodegradation of Certain Components of Town Waste by Thermophilic Fungi

Abstract

An investigation to elucidate the possible role played by the thermophilic fungi in the process of town waste composting was carried out since previous observations had suggested that several species were highly cellulolytic but that very few species had ever been isolated from composting town waste. Biochemical studies on a small town waste windrow confirmed that a high percentage of cellulose was utilised, and that the pH of the waste rose to alkaline values during the thermophilic phase of composting. This suggested that those cellulolytic thermophiles which chad been isolated from composting town waste were successful in colonising this substrate because they were able to adapt to environmental parameters _imposed by such a system, This was partially confirmed by a study of the cellulolytic activity of the twelve cellulolytic thermophiles in isolation, on cellulose perfused with pH-buffered salts, by their inter-reactions on cellulose, and by a study of their Cx cellulase enzymes. The results indicated that the six cellulolytic thermophiles isolated from composting town waste could grow, sporulate, produce active cellulase enzymes and compete together successfully on cellulose under conditions similar to those imposed by the town waste composting process, Suggestions for future work were outlined. The activin of the thermophilic fungi towards synthetic polymers and siketiataies was studied since these materials are found in intr casi quantities within town waste, Polyethylene and polyvinyl chloride were non-biodegradable and a process in which these recalcitrant molecules could be recycled was described. All nineteen thermophiles tested were shown to actively produce esterase enzymes when grown upon ester plasticisers, Finally, all thermophilic fungi under test were able to produce humus substances which were similar in composition to substances isolated from composted town waste.