Biotransformação de resíduos agroindustriais por cultivo em estado sólido de Pycnoporus sanguineus e Thermoascus aurantiacus

Abstract

Agro-industrial waste is an important source of renewable resources. However, inappropriate disposal of this waste can cause serious environmental problems. The biotransformation of agro-industrial residues through solid state cultivation generates enzymes and products with high nutritional value. This work aimed to evaluate the production of fibrolytic enzymes (endoglucanase, β-glucosidase, xylanase and pectinase) by P. sanguineus and T. aurantiacus by CES (wheat bran and sugarcane bagasse 50%:50%, 65% humidity, 28 ºC and 45 ºC respectively) as well as evaluating the bromatological profile and digestibility of the substrate after cultivation. The fungus P. sanguieneus demonstrated greater production of xylanase and endoglucanase in 48 hours of cultivation, β-glucosidase in 120 hours and pectinase in 48 hours. The enzymes presented values close to optimum pH, ranging from 3.5 to 5.5. The optimum temperatures ranged from 50 ºC to 75 ºC. The enzymes were stable over a wide pH range, and 70% of their original activities were maintained when incubated for 1 hour at 65 ºC. The fungus enriched the substrate in proteins (about 14%) and carbohydrates (10%). The fiber and lipid content was reduced by 20.74% and 0.16%, respectively. For digestibility, there was a total increase of 5.63% on the 30th day of cultivation. For the fungus T. aurantiacus, there was greater production of endoglucanase and β-glucosidase in 72 hours, xylanase in 144 hours and pectinase in 72 hours. The optimum pH values ranged from 3.5 to 5.5. The optimum temperatures remained between 60 ºC and 80 ºC. The enzymes were stable over a wide pH range, and 80% of their original activities were maintained when incubated for 1 hour at 75 ºC. For the bromatological composition, the fungus enriched the growth substrate in proteins by 8.8% and carbohydrates by 19.26%. Fiber decay was 23.54%. The lipid content showed an accumulation of 0.16% on the 5th day of cultivation.