An investigation into the pectolytic activity of the yeast Saccharomycopsis fibuliger

Saccharomycopsis fibuliger cells produce an inducible hydrolase, tentatively characterized as a polygalacturonase [poly(1,4-α- d-galacturonide) glycanohydrolase, EC 3.2.1.15], which is associated with the yeast cells and which causes the partial hydrolysis of pectin or poly- d-galacturonic acid. No evidence of pectinesterase (pectin pectyl hydrolyase, EC 3.1.1.11) or pectate lyase [poly(1,4-α- d-galacturonide) lyase, EC 4.1.1.1] activity has been found. Enzyme production took place at an optimum temperature of 28°C, whereas optimum activity was at ∼45°C. The optimum pH for pectolytic activity was similar to the optimum pH for cell growth. A reduction in the concentration of dissolved oxygen in the culture medium and an increase in cell age caused an increase in the rate of pectin decomposition within the limits employed. Products of pectin decomposition consisted of a mixture of uronides including d-galacturonic acid .