Análisis de la diversidad bacteriana durante el proceso de compostaje, e identificación de la presencia de bacterias termófilas, a través de técnicas de biología molecular

Abstract

Composting is an aerobic process in which microbial communities degrade organic substrates in order to generate a product for agriculture. These communities have been studied through traditional culturing techniques, which provide limited results of composition and population diversity; while the metagenomic analysis allow obtaining better results of characterization of microbial communities. In the present study, the behavior of bacterial diversity during the composting process of two large-scale plants, each with different substrates (municipal waste and pig sturgeon), were analyzed. And assessed the relationship of physical-chemical parameters with the richness and microbial diversity. In addition, we isolated and identified thermophilic bacteria and formed a bio-bank of these strains. Bacterial diversity was determined by electrophoretic separation of the amplicons generated, from the 16S region of the rDNA, in denaturing gradient denaturing polyacrylamide gels (DGGE). The identification of thermophilic bacteria was carried out by sequencing and PCR technique with restriction fragment length polymorphism (PCR-RFLP) with AluI enzymes, comparing with restriction patterns obtained from the Serial Cloner and NCBI sequences. The results showed that the two plants under study present a similar diversity value; On the other hand, the type of microbial population within a composting process is defined mainly by the substrate. Likewise, the factor that most correlates with bacterial diversity is pH. In total 45 isolates were obtained from the therm row stage, mainly belonging to the Firmicutes phylum, and to the genera Bacillus, Ureibacillus, Geobacillus, Brevibacillus.