Biodegradation of sugarcane bagasse under high temperature composting; ultrastructural, chemical and microbiological correlations

Sugarcane processing is the most important agro-industry in Mexico. More than 55 sugar factories operate in the country. Sugarcane bagasse, a by-product of sugarcane processing is largely used for burning and production of the energy needed for sugar crystallization. Still, a large amount is sent for aerobic composting, along with filter mud and ashes. Aerobic composting in bio-piles is the most common method of biodegradation of sugarcane by-products. Thermophilic microorganisms, bacteria and fungi, are responsible for the mineralization of lignocellulose in such composts. In order to understand the biodegradation process of bagasse under high temperature conditions, samples from regular and fed-batch compost were taken at different time points during the process, and then analyzed for physical, chemical and microbiological characteristics. Physical analysis such as particle size, apparent density, porosity and water retention were analyzed for every sample. Morphological and structural characteristics were determined by TGA-DSC and XR-EDS; Spectroscopic methods FT-IR and XRD were also used for the analysis of biomaterials during the biological degradation processes. Chemical determination of lignin, cellulose and hemicellulose was

Culturable microbiota was analyzed by the use of selective media enriched with specific polysaccharides and monosaccharides. Specific groups and consortia from bacteria, actinomycetes and different groups of fungi were analyzed, characterized and preserved. Enzyme activities (cellulases and xylanases) were detected in several compost samples.

Further analysis of microbial consortia and correlations with lignocellulose biodegradation patterns will allow for in-depth understanding of the microbial mechanisms of depolymerization and catabolism of lignocellulosic biomaterials.