GROWTH AND PROTOPECTINASE PRODUCTION OF ASPERGILLUS-AWAMORI IN SOLID-STATE CULTURE AT DIFFERENT ACIDITIES

Protopectinases (PPases) are a heterogeneous group of enzymes that rel ease water-soluble pectin from insoluble protopectin in plant tissues by restricted degradation of the substrate, In all experiments reporte d to date, PPases of bacterial or yeast origin were produced in liquid culture, Here, we described the growth and enzyme production of Asper gillus awamori IFO 4033 in solid-state culture at three acidities, Pet ri dishes containing 10 g of wheat bran and 15 mi of 0.2, 0.3, or 0.4 N HCl were inoculated with 2 mi of a suspension of 10(5) spores/ml and incubated for 48 h at 30 degrees C. When 0.2 N HCl was used, PPase ac tivity on lemon (PPase-l) and apple (PPase-a) protopectins was maximum at 24 h of culture (1,490 and 610 U/g, respectively), With 0.3 and 0. 4 N HCl, the PPase activity was highest at 36 h (1,460 and 950 PPase-l U/g, and 400 and 310 PPase-a U/g, respectively). Whatever the acidity , polygalacturonase and pectinase activities were maximum at 48 h, Hen ce, the crude enzyme pool obtained at an early stage of culture was ap propriate for extraction of citrus and apple pectin, The ratio of PPas e-l to PPase-a changed during culture and the acidity affected this ra tio, so there seemed to be at least two PPases with different substrat e specificities.