ISOLATION AND SCREENING OF MOULD STRAINS FOR CLONING AND EXPRESSING PECTINASE GENE

Abstract

Pectinase, an enzyme that degrades pectin, is widely used in the food processing industry for wall softening and extraction of fruit juices; it supports filtering and making fruit juices and wine. From the peels of some fruits rich in pectin, we isolated and screened 113 strains of highly pectinase-active moulds and designated as M1–M113. The number of moulds capable to hydrolyse pectin in the samples ranged from 6,3×10³ CFU/g to 35,1×10³ CFU/g. Two strains, namely M45 and M68, were selected; they showed a strong pectinase activity of 110,2 U/mL and 98,5 U/mL, respectively. The ITS sequencing method revealed that the M45 strain wasidentified as Aspergillus oryzae and the M68 strain as Aspergillus flavus. The ITS sequences of strain A. oryzae (M45) and strain A. flavus (M68) were registered in GenBank with accession number MH746006 and MH746007, respectively.