PROTOPECTINASE PRODUCTION IN SOLID-STATE CULTURE OF ASPERGILLUS-AWAMORI

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 cases reported to d ate, PPases of bacterial or yeast origin were produced in liquid cultu re. Here, we describe the growth and PPase production of Aspergillus a wamori IFO 4033 in solid state culture. Petri dishes containing 10 g o f wheat bran and 15 ml of 0.2 M HCl were inoculated with 2 ml of a sus pension with 1 x 10(5) spores.ml(-1) and incubated for 48 h at 30 degr ees C. PPase activity on lemon (PPase-l) and apple (PPase-a) protopect ins was maximum at 24 h of culture (1490 and 610 U.g(-1), respectively ) and then decreased. Pectinase activity on lemon and apple pectin and polygalacturonase activity were maximum at 48 h. Hence, the crude enz yme pool obtained at 24 h of process was appropriate for extraction of citrus and apple pectin with a minor subsequent degradation of the so lubilized pectin. The ratio of PPase-l to PPase-a changed during cultu re, so there seemed to be at least two PPases with different substrate specificity.