CONSTRUCTION OF BAKERS-YEAST STRAINS THAT SECRETE DIFFERENT XYLANOLYTIC ENZYMES AND THEIR USE IN BREAD-MAKING

cDNAs corresponding to the aspergillus nidulans endoxylanase X22 (xlnA ), X24 (xlnB) and X34 (xlnC) and to the Aspergillus niger alpha-L-arab inofuranosidase (abfB) were placed under the control of the Saccharomy ces cerevisiae actin promotor (pACT1) and introduced into industrial b aker's yeast. Only A. nidulans endoxylanases X24 and A. niger alpha-L- arabinofuranosidase were expressed and secreted properly. Bread made w ith transformant YEpACT-X24 (containing the xlnB cDNA) showed an incre ase in volume around 5%. The combined action of endoxylanase X24 and a lpha-L-arabinofuranosidase on bread did not improve the effects produc ed by the endoxylanase alone. (C) 1997 Academic Press Limited.