Ethanol fermentation of lactose mash by biocatalyzers immobilized in sodium alginate was studied in order to improve the process productivity and economy. The fermentation effectiveness of S.cerevisiae co-immobilized with a p-galactosidase and the directly lactose- fermenting immobilized yeast: K. fragilis and C. pseudotropicalis were compared The application of the immobilized K. fragilis produced desirable results and even after its 9th (18 days) fermentation, the immobilized yeast provided the stable high fermentation level (on average about 6 ralvol of ethano/) while maintaining its activity. Such lactose-mash fermentation was greater than in conventional method (by free cells). In addition, the application of s. cerevisiae co-immobilized with p-galactosidase produced somewhat greater ferm levels than the conventional method, however, the system stability deteriorated after 6 days of fermentation.