Degradação da farinha de penas da indústria avícola por fermentação submersa utilizando isolados fúngicos da Restinga de Guaibim, BA

Abstract

The poultry industry residues and by-products have been solutions for several applications, such as feed production, organic fertilization, biodiesel production, among others. However, the high content of keratin present in a few by-products, such as feather meal, makes this material difficult to digest. The objective of this work was to evaluate the main factors that influence the degradation of feather meal by submerged fermentation using filamentous fungi. The isolates were cultured for a period of 7 days at a temperature of 25 ºC, using as inoculum 1.0 cm diameter culture discs in 250 ml Erlenmeyer flasks containing 0.6 g of feather meal and 60 ml of solution mineral. Then, the tests were autoclaved and a simple filtration was performed to extract the juice with filter paper previously, drying the biomass in an oven at 65° C for 24 hours and, later, weighing. The rate of degradation was determined by the difference between the mass of the empty filters and the dry biomass. In order to determine the best conditions for degradation of feather meal, the factors of agitation and temperature were studied, using the one-factor-at-a-time method, where the chosen factors were varied one at a time. All tests were performed in triplicate. According to the analysis of the results there was no significant difference between the agitations, however, the isolate Metarhizium IS15 presented a degradation rate about 50% higher than the isolate P. guaibinense IS25.2. The temperature at which the isolates showed the highest rate of degradation was 30 ° C, about 80% for Metarhizium IS15, and 42% for P. guaibinense IS25.2. After the fermentation period, an increase in the pH of the fermented crops was observed, changing from 6.5 to about 8.0. The isolated Metarhizium IS15 was the one that presented the best potential for degradation of the feather flour, and temperature was the main factor that interfered with feather activity. microorganisms.