CELLULASE ENZYME RECOVERY FROM MOLD STRAINS ISOLATED FROM COFFEE SOURCES IN VIETNAM

Abstract

This study focused on isolating two strains of mold, Aspergillus and Trichoderma, with high cellulase enzyme activity from several sources such as coffee soil, moldy coffee berries, and rotting coffee stems. The isolated mold strains were classified based on macroscopic and microscopic observations. Simultaneously, a qualitative process of cellulase production capability was carried out by measuring the diameter of the Carboxymethyl cellulose (CMC) resolution zone. Based on these results, a mold strain with the ability to produce highly active cellulase enzyme was selected. Finally, the cellulase enzyme was obtained from the selected mold strain by fractional precipitation with ammonium sulfate salt. The results showed that out of a total of 24 mold strains, 13 strains were same Aspergillus characteristics, and 11 strains were same Trichoderma characteristics. The strain Trichoderma asperellum QT5 showed the highest CMC resolution zone diameter and Carboxymethyl cellulase assay (CMCase) activity 19.5 mm and 1.17 U/mL, respectively. After the preliminary purification process, the cellulase enzyme was obtained from T. asperellum QT5 with the highest specific activity of 43.92 U/mg, and the recovery efficiency reached 70.51%. The results of the study have contributed to opening up the possibility of applying crude cellulase enzyme in production to reduce product costs as well as fully exploiting this natural source of mold.