The Janthinobacterium lividum chi69 chitinase gene linked to the Kluyveromyces lactis killer toxin secretion signal was ligated to the galactose-inducible CYC-GAL hybrid promoter of pEMBLyex4 and transferred directly into Saccharomyces cerevisiae DY-150. Exogenous chitinase activity assayed with 4-methylumbelliferyl-beta-chitotrioside reached a maximum of 0.7 U/ml in the growth medium after 24 h galactose induction without any apparent deleterious effects on the yeast expression host.