A low-cost industrial grade lactase was developed for one-time use in dairy products. The preparation contained the entire biomass of a selected hyperproducing strain of the yeast Kluyveromyces fmgi/is. Intracellular lactase .was made freely accessible to its substrate by permeabilization of the cell membrane with food compatible reagents. In 0. IM phosphate plus 0.4% methyl paraben, permeabilization was complete in 0.5-l hr at 5O"C, with 90% activity recovery from 180 g/L of cells. Whole-cell lactase contained no viable cells and was free of proteolytic activity. Its pH optimum of 5.6-6.0 proved suitable for lactose hydrolysis concurrent with cottage cheese fermentation. Hydrolyzed whey was used in ice cream and bakers' yeast production.

No abstract