SYNTHESIS OF ISOPROPYL-1-THIO-BETA-D-GLUCOPYRANOSIDE (IPTGLC), AN INDUCER OF ASPERGILLUS-NIGER B1 BETA-GLUCOSIDASE PRODUCTION

Production of beta-glucosidase in Aspergillus niger B1 is subjected to catabolic repression by glucose. Aspergillus niger B1 grown on bran a s a carbon source secreted beta-glucosidase. The maximum level of the enzyme was reached after 7 d of fermentation. Addition of 1% glucose t o the medium suppressed beta-glucosidase production to undetectable le vels. In this study, the organic synthesis of a potential inducer of b eta-glucosidase production by A. niger B1's reported. Isopropyl-1-thio -beta-D-glucopyranoside (IPTGlc) was synthesized using a two-step orga nic synthesis protocol. The H-NMR data agreed with those reported prev iously for the galactoside analog. When IPTGlc was added 24 h after in oculation at a final concentration of 0.4 mM, similar levels of beta-g lucosidase were reached 3 to 4 d earlier as compared to fermentation w ithout IPTGlc induction. In practice, this may translate to a more eff icient method of producing beta-glucosidase from this fungus.