Composting sugar cane bagasse at full scale: Organic matter decay kinetics, metagenomics and plant-growth promoting bacteria capabilities

Abstract

The management difficulties implied at field-scale composting make difficult to perform kinetic studies, leading to a gap in the literature at real enterprise conditions. Although composting has been reported to show a three-phase kinetics regarding the temperature, for organic matter, an exponential decay kinetics has been described. Organic matter decay, internal temperature of sugar-cane bagasse compost windrows along the time at enterprise (field-scale) level and the microbial community of the final product were analyzed. Final compost was achieved at 12-17 weeks with 41-47 % humidity and 31-47 % organic matter content. Kinetics model of organic matter biodegradation showed R2 ≥ 0.6 and no differences between exponential or linear model R2 were observed. Linear biodegradation constant was 2.5 % of organic matter loss/week, ranging from 2.2 to 3.7 %/week. The most abundant bacterial classes were Bacilli and Anaerolineae from metagenomic analysis. Bacterial cultures isolated showed plant-growth promoting and aromatic degradation capabilities. This shed light to future prospection studies on real-world composting for enterprises and scientists.