Production and Biochemical Characterization of Aspergillus japonicus Pectinase Using a Low-Cost Alternative Carbon Source for Application in the Clarification of Fruit Juices

Pectinases are a complex group of enzymes that degrade pectic substances. We produced pectinases efficiently using wastes/agro-industrial products through submerged fermentation (SC) and solid-state fermentation (SSC), making the production cheaper. Passion fruit peel was the best inducer of pectinase production by Aspergillus japonicus during SSC. The biochemical characterization of the pectinase showed that the best pH and temperature for pectinase activity were pH 4.0 and 60 °C. The stability of pectinase was evaluated at different pH, and the enzyme was observed to be stable for 4 h at all tested pH, and maintained 88%, 84%, and 72% of its activity at pH 3.0, 4.0, and 5.0, respectively, after 24 h. A. japonicus pectinase was superior to the commercial pectinase (Pectinex) in clarification of almost all the fruits tested. Pectinase application achieved the best clarification in mango (Haden) pulps (85.56%), whereas Pectinex only clarified 50.89%. Moreover, in apple (Argentina), A. japonicus pectinase showed 66.32% clarification, whereas Pectinex only showed 12.67% clarification. Furthermore, in apple (Europe), banana “da terra”, mango (Palmer), and white guava, A. japonicus pectinase showed 52.59%, 49.04%, 46.7%, and 46.4% clarification, respectively, whereas Pectinex showed lower or significantly similar results with 13.34%, 38.29%, 49.3%, and 33.6% clarification, for the same pulps, respectively. A. japonicus pectinases have properties that enable them to efficiently clarify various types of juices. Additionally, their production is inexpensive. Graphical Abstract