Characterization of pectinases from Acrophialophora nainiana and Trichoderma harzianum strain T6

Abstract

Two pectinase preparations have been isolated from liquid-state cultures of Acrophialophora nainiana and Trichoderma harzianum strain T6 containing pectin as the carbon source. Pectin lyase and pectin methylesterase activities were only detected in the enzyme preparations from A. nainiana. The exo-polymethylgalacturonase from A. nainiana was most active at pH 7.0 and 60oC, while exo-polymethylgalacturonase optimal activity from T. harzianum strain T6 was obtained at pH 4.3 and 40oC. Their stability at 40, 50 and 650C differed, being the exo-polymethylgalacturonase activity from A. nainiana more stable. Both enzyme preparations showed good stability at acidic pH. The crude extracts were partially purified by ultrafiltration, and gel filtration chromatography on Sephacryl S-100. Kinetic parameter studies showed that the lowest Km values were obtained with exo-polymethylgalacturonase from T. harzianum strain T6. The treatment of fruit juices with pectinase samples from A. nainiana and T. harzianum strain T6 resulted in a decrease of viscosity. Pectinase from T. harzianum strain T6 appeared to be more effective in the reduction of turbidity from apple juice. Only pectinase from T. harzianum strain T6 was able to extract juice from banana fruit.