About thirty-five percent of coffee pulp waste is pectin. It may potentially be a source to be used in the bioprocessing industry. For example, it can be used as a substrate to produce pectinase from microorganisms under solid-state fermentation (SSF). In this investigation, an isolated fungus VTM4 with density 107 spores/mL was grown on coffee pulp medium-based, and after 0-168 hours incubation at 30 °C, pectinase activity was detected. The activity was measured based on reducing sugar released by crude pectinase against 0.5% alkali extract pectin substrate in 20 mM buffer acetate pH 5. The highest reducing sugar produced was 223.34 µg/mL after 72 hours of incubation at 30 °C. The optimum pH on enzyme activity was 4 with the maximum activity 0.747 U/mL and was stable (more than 80%) at a pH range of 4-5.5. The results revealed that the coffee substrate could be utilized as a carbon and nitrogen source to produce pectinase. Further research on purification and characterization of the enzyme to improve pectinase yield production was needed.

Pectinase is a heterogeneous enzyme that hydrolyzes pectin, which is currently in high demand in the industry, so a strategy is needed to produce it economically. Aspergillus VTM4 is a mold that can grow on pomelo pulp and produce pectinase. Under solid-state fermentation, the crude pectinase was produced with the activity of 1.6 U/ml when 10 gr of dried pomelo pulp was inoculated by 10 7 spores of Aspergillus sp. VTM4 and incubated for 48 h at 30 °C. After dialysis using a cellulose membrane tube 12-14 kDa, the pectinase activity was increased by 0.182 U/ml. Further purification step on the DEAE-Cellulose DE-52 open column with a gradient of NaCl 0-0,6M in 20 mM acetate buffer pH 5 was carried out. The peak fraction as pectinase activity increased to 0.369 U/ml with 1,516 purification fold and 5,3% yield. Based on these results, it can be proved that pomelo pulp can be used as a substrate for pectinase production by Aspergillus VTM4. Further research to analyze the properties and characterize the stability of pectinase against temperature, pH, the effect of heavy metals, and molecular analysis is needed. Complete steps and results of this investigation are discussed in this paper.