CLONING AND EXPRESSION OF A GLUCOAMYLASE GENE FROM LACTOBACILLUS-AMYLOVORUS ATCC-33621 IN ESCHERICHIA-COLI

The glucoamylase gene from Lactobacillus amylovorus was cloned and exp ressed in Escherichia coil. A genomic DNA library from Lactobacillus a mylovorus was prepared by partially digesting genomic DNA with EcoRI a nd ligating random fragments to the EcoRI digested cloning vector, pZE rO-1.1. Three E. coil transformants expressing glucoamylase were ident ified using a probe prepared from the STA2 glucoamylase gene from Sacc haromyces cerevisiae var. diastaticus. The physical maps of the recomb inant plasmids were constructed. These plasmids contained inserts of a bout 5.2 Kb, 5.9 Kb and 6.4 Kb respectively. Temperature and pH optima of 45 degrees C and 6.0, respectively, were obtained for both recombi nant and purified wild type glucoamylases. Also, the enzymes were foun d to be thermolabile at temperatures above 50 degrees C.