Glucose effect on the biodegradation of plastics by compost from food garbage

Abstract

The variation of physicochemical properties and microbial population were examined in the course of a food garbage composting, and the biodegradation of several plastics in the compost was investigated. Moisture content was controlled in the range of 64+/-4%, and the thermophilic stage lasted about 2 weeks. In the initial stage of the composting, mesophilic strains were more numerous than thermophilic ones. As the thermophilic stage set in, thermophilic bacteria and actinomycetes outnumbered mesophilic correspondents while fungi were not detected at all. In the cooling and maturing phases, lots of actinomycetes were still found. However bacteria decreased significantly in number, and only a small number of mesophilic fungi reappeared, When glucose was added to the compost, the so-called "priming effect" was observed, in that the amount of CO2 evolved was larger than that predicted by assuming that all the added glucose was mineralized into CO2. However the priming effect decreased as the quantity of the glucose in the compost increased. Addition of 5 wt.% of glucose to the compost increased the number of micro-organisms by 10-100 times. Addition of some biodegradable plastics also increased the number of micro-organisms. However the increased number of microorganisms was not dependent on the biodegradability of the added plastics. (C) 2002 Published by Elsevier Science Ltd.