ABSTRACT
The quality of the carbon used as bulking agent in the composting process directly affects the dynamics of the waste degradation, which is governed by an active and diversified microbiota. The monitoring of the basal respiration and enzymatic activities during the composting of broiler agro-industrial wastes with different carbon sources as bulking agents was the aim of this study. The microbiological activities were more intense in the thermophilic phase of the process. The dynamics of the enzymatic activities were affected by the different carbon sources used as bulking agent in the composition of the windrows. When the milled sugarcane bagasse was used as carbon source, the windrow presented the highest amount of P in its constitution and presented, in the evaluation averages, a greater intensity of the alkaline phosphatase enzyme (842 μg g−1 h−1 p-nitrophenol compost); the highest intensities of β-glucosidase and cellulase enzymes were observed when fresh and ground napier grass was used as the main source of carbon (6.1 μmol g−1 h−1 p-nitrophenol compost and 35.2 μmol g−1 16h−1 glucose compost, respectively); the highest intensity of the urease enzyme was also observed in the windrow where napier grass was used as the main carbon source and bulking agent (205,890 μmol g−1 2 h−1 N-NH4+ compost). It can be concluded that napier grass when used as the main source of carbon and bulking agent in the composting of the wastes from broiler chicken production chain promotes greater intensity of most of the enzymatic activities of interest. The enzymatic activity of urease presented the highest values due to the high nitrogen content of the composted wastes.
KEYWORDS
basal respiration; alkaline phosphatase; pH; β-glucosidase; cellulase; urease
