摘要：Lactose hydrolysis, which is of great concern due to nutritional, technological and environmental reasons, has been performed in skim milk using Kluyveromyces maxrianus cells. The yeast cells were permeabilized using ethanol in order to overcome the problem of poor permeability of cell membrane to lactose and subsequently immobilized by entrapment method in calcium alginate and agar-agar gel. The effects of gel concentration, temperature and treatment time on the performance of both the immobilized yeast cells preparations were investigated. Maximum hydrolysis (87.8%) of milk lactose was achieved with alginate entrapped yeast cells. The lactose hydrolysis reaction (in terms of loss of substrate as a function of time) using immobilized yeast cells can best be described as first order with half-life of ~ 44.4 minute for alginate gel in comparison to that of ~ 63 min for agar at 30°C in a batch process. Thus, former immobilization support/matrix is more efficient in lactose hydrolysis and demonstrated greater potential for future commercial application.
