Filamentous fungi and agro-industrial residues selection for enzyme production of biotechnological interest

Abstract

Many fungal enzymes have relevant applications in different industrial areas. The objective of this work was to select fungi producing hydrolytic enzymes, as well as establish agro-industrial wastes capable of inducing higher production levels. Xylanase, endoglucanase, amylase and poligalacturonase activities were determined by incubating the culture filtrates with their respective substrates. Subsequently, the reducing sugars determination was carried out using 3,5-dinitrosalicylic acid reagent.The protein determination was performed according the modified Bradford method. Among the fungal strains evaluated, Aspergillus niger J4 showed higher levels of xylanase production (8.73 ± 0.34 U/ml) and this was greatest when brewer's spent grain was used as substrate (9.80 ± 0.02 U/ml). Penicillium miczynskii produced the highest levels of endoglucanasic activity (0.13 ± 0.03 U/ml), which, in turn, was favored in the pineapple peel presence (0.18 ± 0.02 U/ml). In relation to amylase, A. niger J26 was selected as the best producer strain (6.10 ± 0.30 U/ml) with wheat bran as the best substrate for their production (7.32 ± 0.14 U/ml). Penicillium verruculosum exhibited the highest level of poligalacturonase activity (8.65 ± 0.12 U/ml)), especially when grown in orange peel presence (10.32 ± 0.10 U/ml). These wastes use in these enzymes production may not only reduce their production cost, but also substantially reduce the environmental impact caused by the deposition of these wastes on the environment.