Production, characterization and application of polygalacturonase produced by Lentinus tigrinus CCMB 553

Abstract

Polygalacturonases can be used to improve the processing of fruit juices and wines. This study aimed to produce, characterize and evaluate the potential application of polygalacturonase obtained from Lentinus tigrinus CCMB 553 in mango juice clarification. The fungal was isolated from the northeastern semi-arid region and fermented using Passiflora cincinnata bark as a substrate for solid state fermentation. The optimal conditions for enzyme production were obtained by applying the three-level factorial experimental design and were defined as 9 days and 30 °C for time and temperature, respectively. The optimal pH and temperature were determined by applying the Doehlert design and the results showed higher production between 45 and 60 °C and 4.0 and 5.5 for temperature and pH respectively. Km and Vmax of polygalacturonase from Lentinus tigrinus were 2.7 mg/mL and 12.86 μmol/min. The enzyme maintained 40 % residual activity after 30 min at 80 C. The influence of cations on enzyme activity was studied, and calcium ions seem to have a positive influence on enzyme activity, while Fe2+ ions have a negative influence. K+, Na+ and NH4+ salts showed little influence on the polygalacturonase activity of Lentinus tigrinus. The application in the clarification of mango juice (Mangifera indica) using optimal conditions obtained resulted in a reduction of 45% of the viscosity and the clarification by about 79%. The results show that the polygalacturonase produced by Lentinus tigrinus CCMB 553 was efficiently applied in mango juice, improving the quality of the juice.