Lactose hydrolysis using a disrupted dairy culture: Evaluation of technical and economical feasibility

The feasibility of producing partially-lactose-hydrolyzed (PLH) milk or syr up using a crude source of beta-galactosidase from a disrupted dairy cultur e (L. delbrueckii subsp. bulgaricus 11842) was examined. Ascertaining that the disrupted biomass from a 1000 L fermentation is capable of producing at least 1000 L of PLH milk (60% hydrolysis), production of one or two 2000 L batches per week would be economically feasible provided the processing fa cility already owns a suitable bactofuge. The hydrolysis of a 50,000 L batc h of milk at least two days per week appears feasible despite the need for a $7.5 million capital investment. Production of sweetening syrup (65% soli ds, 60% hydrolysis) from whey or permeate does not appear economically feas ible based on the hydrolysis of 500,000 L of whey or permeate per day (85% operating factor). Partially-lactose-hydrolyzed milk is a high-value added product, but syrups produced from hydrolyzed whey or permeate would have to compete with other inexpensive sweetener commodities.