DNA CONSTRUCT AND MODIFIED YEAST

摘要

A DNA construct is described which comprises DNA encoding for a beta -galactosidase which can be secreted by a yeast, said DNA being flanked at its 5' end in reading frame by a yeast promoter sequence. Such DNA constructs can be incorporated in a plasmid vector (e.g. pVK11) and inserted into a suitable host, such as a yeast (e.g. Saccharomyces cerevisiae), to produce a microorganism which synthesises and secretes beta -galactosidase extracellularly or into the periplasmic space and which can grow on a substrate containing lactose, e.g. whey or whey permeate. The DNA coding for the beta -galactosidase may be of fungal origin, for example it may be derived from Aspergillus niger in the form of its lacA+ gene.