FACTORS AFFECTING PRODUCTION OF EXTRACELLULAR PECTOLYTIC ENZYMES BY PHYTOPHTHORA PALMIVORA (BUTL) BUTL

The nutritional requirements of Phytophthora palmivora in relation to extracellular pectolytic enzyme production were investigated. These were found to be different from those necessary for mycelial growth. The best carbon source for enzyme production was maltose. The best inorganic nitrogen source for enzyme production was calcium nitrate, the effect of which could not be related solely to the calcium ions; DL-alanine was the best organic nitrogen source for enzyme production. Evidence was obtained to indicate that polygalacturonase (PG) and a maceration factor (MF) were constitutive, but that α-L-arabinofuranosidase (AF) secretion was induced by arabans present in pectin.The extrinsic factors in relation to growth and enzyme secretion were also investigated. Both mycelial growth and enzyme production could be broadly related to the incubation period, temperature, and the pH of the media. Two peaks of PG and AF activities were recorded corresponding to the phases of optimum growth and autolysis of the mycelium, respectively. When five isolates were compared, the mycelial growth could not be related to the quality of enzymes produced. © 1969 OXFORD UNIVERSITY PRESS.