Degradação de resíduos e subprodutos da indústria avícola por fungos filamentosos isolados da restinga de Guaibim, BA

Abstract

The inadequate disposal of feathers from the poultry industry causes environmental impacts.The incorporation of enzymatically degraded feathers into animal feed or vegetable fertilizer is indicated as an environmentally safe destination for this type of residue. In this study, nine fungal isolates belonging to nine different genera from the proteolytic fungi collection of the Laboratório de Biologia Evolutiva (LABEV) of the Universidade Federal do Recôncavo da Bahia. The objectives of this study were to identify by molecular phylogeny fungus degraders of chicken feathers and to evaluate the degradation of residues of the poultry industry by filamentous fungi in different submerged fermentation conditions. Phylogenetic analyzes have shown that the isolates are phylogenetically related to the species Aspergillus hortai, Lecanicillium aphanocladii, Penicillium guaibinense, Purpureocillium lilacinum, Fusarium oxysporum, Trichoderma harzianum, Cladosporium tenuissimum, Metarhyzium anisopliae , Acremonium borodinense and Acremonium pinkertoniae. The isolates Metarhizium sp. IS15 and Cladosporium sp. demonstrated to belong to two new species found in the restinga of Guaibim. The degradation assays revealed that there is no influence of the effect of the compositions of the two saline media on the percentages of degradation obtained by the isolates. The autoclaving condition of the chicken feathers influenced their hydrolysis and the profile of enzymes secreted by the fungal isolates during the submerged fermentation. In turn, the autoclaving condition did not influence the degradation of viscera flour by fungal isolates, which varied from 25.1 to 54.8% indicating that they also have biotechnological potential for the conversion of this by-product of the poultry industry into bioproducts with higher value added. Alkaline pHs was recorded for all treatments in the degradation tests of residues and by-products. The test of degradation of feather meal by Metarhyzium sp. IS15 indicated that the highest percentages of degradation were observed in the treatments that used the central values of the experimental design, with 75.60 - 77.57% substrate degradation, and that it is possible to obtain higher percentages of degradation with this substrate. It is hoped that this study will contribute to the development of actions for a better reuse of by-products of the poultry industry in addition to increasing knowledge about the biodiversity of microorganisms found in the restinga.