PARTIAL CHARACTERIZATION OF ASPERGILLUS-FUMIGATUS POLYGALACTURONASES FOR THE DEGUMMING OF NATURAL FIBERS

Aspergillus fumigatus strain 4, cultured on citrus pectin as the sole carbon source, produced polygalacturonases whose activity was optimum at 65-degrees-C and pH 3.5-4.5. The enzymes presented a bimodal thermo stability for 10 min, but not 60 min, of incubation. Polygalacturonase s showed pH stability between 3.0 to 9.0. The enzymes were stable when stored at 4-6-degrees-C for 90 days, but their activity was reduced b y 24% when they were stored at 26-30-degrees-C. Orange pulp was the be st pectic carbon source tested for the production of pectinases capabl e of retting ramie fibers. The reutilization of these enzymes was poss ible, suggesting the viability of industrial use of pectinases for deg umming ramie fibers.