Estudo da microbiota durante a fase ii da compostagem para produção do substrato de cultivo do cogumelo Agaricus blazei

Abstract

The study of different microbial population occurring in the cultivation compost for Agaricus blazei is of fundamental importance for the understanding of their role in the final properties of the compost. Therefore, this work was divided in three distinct stages involving different compost formulation. In the first stage the bacterial population of fase II in four compost formulations with final concentration of N 1,0%; 1,5% and 2,0% were evaluated. It was possible to observe the highest incidence of the genus Bacillus in both composts. Also it was found that were 22 differents Gram-negative species, among them, some pathogenic species. In the second stage the behavior of Scytalidium thermophilum was verified. The fungus was inoculated in compost with a final N concentration of 2,0%, at the start of fase II. The presence of this fungi was observed during the conditioning increasing its population. However this fungus was found at these days of mycelial colonization by A. blazei. Finally, in the third stage filamentous fungi were identified as contaminants of a traditional compost used for A. blazei cultivation after pasteurization and before inoculation. The filamentous fungus were also found in two other composts based in cotton residue with concentrations of 30% and 45% cotton at 40 days of mushroom colonization. Species of Aspergillus fumigatus, Aspergillus niveus, Aspergillus ochraceus Aspergillus terreus, Emericella nidulans, Penicillium funiculosum, and Penicillium oxalicum were found. The compost contends 30% cotton only presented A. fumigatus, A. niveus and P. oxalicum. The 45% cotton compost presented higher contamination indexes and the A. fumigatus species occurred most in both composts.