Characterization of polygalacturonases produced by the endophytic fungus Penicillium brevicompactum in solid state fermentation - SSF

Polygalacturonases belong to the family of pectinases, enzymes that are in high demand in industry because of their many different applications. This study therefore sought to examine the production of polygalacturonases using an endophytic fungus, Penicilium brevicompactum, isolated from Baccharis dracunculifolia D.C. (Asteraceae) through semi solid fermentation using orange peels and citric pectin 2% as base substrate, supplemented with different carbon sources. After the fermentation process, the enzyme was characterized. The results showed that the micro-organism was able to use a wide range of carbon sources, but with polygalacturonase activity varying with each source. The highest yield, however, was achieved after 30 hours of incubation in the presence of 4% of galactose and 2% of pectin. Studies on the characterization of the polygalacturonase revealed that the optimal temperature of this enzyme is 72°C and that it maintains 60 and 15% of its maximum activity when incubated for 2 hours at 40 and 90°C, respectively. The optimal pH for the activity of the enzyme was 4.6. The enzyme retained 65 and 30% of its maximum activity when incubated at pH 3.5 and 9.5, respectively, for 24 hours at ambient temperature. The enzyme activity was stimulated by Mg2+ ions. On the other hand, it was inhibited by the ions Cs+2, Hg+2, Li+2 and Sr+2. The ions Zn+2 and Cu+2 inhibited it by 94% and 69%, respectively.