THE INFLUENCE OF YEAST ON THERMOPHILIC COMPOSTING OF FOOD WASTE

The microbial changes during thermophilic composting of food waste wer e investigated at 50 degrees C using a laboratory-scale composter. The results showed that an early increase in the growth of yeast was foll owed by the growth of thermophilic bacteria, and that subsequently, th e yeast declined rapidly. The growth interactions of selected strains of yeast and bacteria were studied in culture media containing organic acids. The results demonstrated that the acidity of the media was red uced during the growth of the yeast. Therefore, it is concluded that i n the early stages of composting, the growth of thermophilic bacteria is inhibited by organic acids, and that the growth of yeast enables su bsequent bacterial growth by removing organic acids from food waste.