Fungal diversity during composting of agricultural wastes

GALZENATI VANINA, BRESSAN FABIANA, CRESPO DIANA, CARMARÁN CECILIA

Villa Carlos Paz, Córdoba, Argentina

Congreso; VI Congreso Argentino de Microbiología General; 2009

SAMIGE- Sociedad Argentina de Microbiologia General

Composting is an aerobic biotransformation of solid organic waste in stable products, free of pathogens that can be applied to improve soil characteristics. During this process, physical and chemical changes occur that determine the biodiversity, which the temperature is the major selective factor for determining the composition of microbial community. Fungi, bacteria and actinomycetes constitute the microbial community in the compost. In this work, we studied fungal diversity associated with the composting of agricultural wastes (poultry manure + rice hulls + wood thin shaving). Samples were taken at four times, corresponding to different composting stages. For the screening, four culture media were used: Potato dextrose agar (PDA), Carboxy-methyl cellulose agar (CMC), Minimum medium + rice hulls (RHA) and Minimum medium + shredded paper (SPA) and for the identification, the isolated strains were identified by macro and micromorphologic characteristics. Beside, changes in temperature, electrical conductivity, moisture content, pH and C/N ratio were registered. A total of 300 fungal isolations were obtained. The more represented genera were Penicillium, Cladosporium, Aspergillus, Alternaria, Epicoccum and Trichoderma. The major number of strains were obtain in the first sampling (mesophilic stage). In the next phase (thermophilic stage), the number of strains declined and in the following stages an increase in number of recovered strains was observed. Physical and chemical data were partially correlated with changes on the fungal diversity. The implications on the process are analyzed. Penicillium, Cladosporium, Aspergillus, Alternaria, Epicoccum and Trichoderma. The major number of strains were obtain in the first sampling (mesophilic stage). In the next phase (thermophilic stage), the number of strains declined and in the following stages an increase in number of recovered strains was observed. Physical and chemical data were partially correlated with changes on the fungal diversity. The implications on the process are analyzed.