Enzyme activities during composting of waste microbial biomass from pharmaceutical industry

A mixture of wood chips and waste microbial biomass remaining after fermentation and isolation of a pharmaceutical product was treated by composting in a perforated plastic box for five days in several experiments. Maximum temperature of 57 degreesC was reached, pH varied between 5,6 and 8,3 while humidity was in the range of 56,5% to 51,5%. Different enzyme activities were detected already in the initial mixture for composting, some of them originating from the waste microbial biomass, others from the wooden structure material. Proteases, esterases, cellulases, amylases and two ligninases: laccase and manganese peroxidase were active during the process. In some experiments also some xylanase activity was present. The measured enzymes were extracellular, however, in the case of cellulases, the activity was mostly associated to the cell membrane.