Isolation and screening of aerobic microorganisms that produce pectinase and cellulase from cocoa tree (Theobroma cacao)

Abstract

Pectinase and cellulase were important enzymes in cocoa fermentation. This thesis focused on the isolation of aerobic microorganisms on the leaves, stem and fruit of cocoa tree and screening their cellulase and pectinase activities. The samples of cocoa tree were collected at University of Agriculture and Forestry. After the isolation, there were 7 strains of microorganisms. The plate assay using iodine was the method for screening of cellulase and pectinase activities. The sample L2.1, L3.3, L3,2 and F2.1 had enzyme activity. The sample F2.1 and L2.1 had pectinase and cellulase while the sample L3.3 and L3.2 had the pectinase only. Those samples were sent to Nam Khoa company for identification by 16S and 28S rRNA gene sequencing. The result showed that there were 3 strains of microorganisms including Aspergillus clavatus, Pichia kudriavzevii and Klebsiella pneumoniae. Pichia kudriavzevii was the common yeast found on cocoa fermentation heap (Van Thi Thuy Ho et al., 2013) and Aspergillus clavatus was the filamentous fungi originated from the soil of crops of banana or corn (Brian Flannigan et al., 2010). Klebsiella pneumoniae was the bacteria found on the soil and water and it may cause some diseases in human and animals. However there was research that had mentioned the ability of using them to produce pectinase (Muhammad Sohail, 2012). Those microorganisms were not well known for enzyme production but they could provide the information for further studies of cocoa fermentation in Vietnam. Keywords: Enzyme Cellulase Cocoa fermentation Microorganisms Pectinase