Background: Pectin enzymes are biocatalysts that degrade pectin into simpler forms. Fermentation is the commonly utilized method for pectinase production. Prior to optimization of pectinase activity, preliminary findings were undertaken to select the best screened microbe (Aspergillus niger), agrowastes and extraction solvents. Solid-state fermentation was employed in the study (optimization process), utilizing the Box-Behnken design in Design-Expert software package version 12.0.3. Results: The results showed 0.1 molar sodium chloride as the best extraction solvent, with the activity higher than the citrate buffer. However, pectinase activity obtained with distilled water was significantly (p<0.05) lower than 0.1 molar sodium chloride. For the substrates employed in the study, the citrus (orange) peel had the highest pectinase activity of ≈0.40 mg per ml. The activity of citrus peels was significantly higher than the activities from each of corn cob, banana peel, wheat bran, Thaumatococcus danielli fruit wastes and Thaumatococcus danielli leaves. A significant increase (p<0.05) in pectinase activity was also obtained with Thaumatococcus danielli fruit wastes relative to Thaumatococcus danielli leaves. Pichia kudriavzevii strain F2-T429-5 and Pichia kudriavzevii strain CY902 have been identified to complement for pectinase production. From the results obtained, the optimum conditions for pectinase production were approximately 5.87 days of fermentation; pH of 3.90; at 21.24 oC; particle size of 0.06-inch; inoculum volume of 1.00 ml, and agitation time (for pectinase extraction) at 11.43 minutes. Optimisation of the selected conditions using the Box-Behnken design and analysis as a statistical tool resulted in a higher activity. Conclusion: Local production of pectinase would help in reducing hunger through local job creation, thereby positively contributing to the Sustainable Development Goals (SDGs).

Background: Owing to the importance of enzyme in fruit processing, demand in quality pectinase has increased. As a result, understanding the properties of locally produced pectinase is very important to encourage promotion in its application in the industry. In this study, Aspergillus niger was isolated, screened for its ability to secrete pectinase. The screened Aspergillus niger was used to produce pectinase using solid state fermentation of orange peels. Results: The effect of temperature and its stability, pH and its stability, substrate concentration, metal ions (Na+, Ca2+, Mg2+, K+, Mn2+, Zn2+, Co2+, and Fe2) were also investigated. The characterized pectinase was applied in the clarification of both orange and pineapple juices. The findings revealed that the enzyme was most effective at 50oC and relatively stable at 20oC activity of about 0.50 mg/ml for both. The optimal pH of 5 at about 0.50 mg/ml, and stabilized pH of 4 with approximately similar activity was also obtained. Of the metals ions investigated, Na+ gave the highest activity of about 0.61 mg/ml compared to ethylenediamine tetraacetic acid (EDTA) which displayed an inhibitory effect. On further optimizing for the concentration of Na+, low concentration of the ion (10 mM) had higher activity of about 0.61 mg/ml. The (Km) and Vmax was about 0.36 mg/ml and 4.39 U/ml. Conclusion: The characterized pectinase clarified both orange and pineapple juices, with enhanced clarification in orange juice compared to pineapple juice. Therefore, the characterized crude pectinase was suitable for application in the clarification of juices.