Partial characterization of Aspergillus fumigatus polygalacturonases for the degumming of natural fibers

Abstract

Aspergillus fumigatus strain 4, cultured on citrus pectin as the sole carbon source, produced polygalacturonases whose activity was optimum at 65°C and pH 3.5-4.5. The enzymes presented a bimodal thermostability for 10 min, but not 60 min, of incubation. Polygalacturonases showed pH stability between 3.0 to 9.0. The enzymes were stable when stored at 4-6°C for 90 days, but their activity was reduced by 24% when they were stored at 26-30°C. Orange pulp was the best pectic carbon source tested for the production of pectinases capable of retting ramie fibers. The reutilization of these enzymes was possible, suggesting the viability of industrial use of pectinases for degumming ramie fibers. © 1993 Society for Industrial Microbiology.