Induction of the Synthesis of Endo-1,4-β-xylanase and β-Galactosidase in Original and Recombinant Strains of the Fungus Penicillium canescens

Abstract

The induction of synthesis of the secreted enzymes endo-1,4-β-xylanase (EC 3.2.1.8) and β-galactosidase (EC 3.2.1.23) in original and recombinant Penicillium canescens strains has been studied. In all producer strains, the synthesis of these enzymes was induced by arabinose and its metabolite arabitol. The two enzymes differed in the concentration of arabinose required for induction: the synthesis of β-galactosidase was most pronounced at 1 mM, whereas maximum synthesis of endo-1,4-β-xylanase was observed at 5–10 mM. An increase in the number of endo-1,4-β-xylanase copies in the high-copy-number strain of the fungus suppressed the synthesis of β-galactosidase; the synthesis of endo-1,4-β-xylanase in the high-copy-number recombinant producing β-galactosidase was affected to a lesser extent. The amount of enzymes synthesized did not depend on the saccharide used as the sole source of carbon for growing the mycelium prior to its transfer to the inducer-containing medium.