Production of lysozyme-enriched biomass from cheese industry by-products

Cheese whey and cottage cheese whey are by-products of the milli and cheese industry resulting from the production of cheese and cottage cheese (ricot ta) from milk. They are still rich in organic substances and cannot be disc arded into the environment without proper treatment. Whey and cottage chees e whey were used as culture media for some strains of the yeast Kluyveromyc es lactis, transformed with the human lysozyme gene. It was found that the yeast strains grew well in both media and produced a considerable amount of recombinant protein. Production kinetics showed that the human lysozyme wa s produced in a greater amount within 36 h of fermentation (125 mu g ml(-1) vs 25 mu g ml(-1) in the control) than in the synthetic commercial media u sed for strain preparation and characterization. The recombinant protein pr oduced was actually shown to be the human lysozyme, using renaturing SDS-PA GE and Western blot techniques. While producing recombinant protein, the Kl uyveromyces strain cleared the cottage cheese whey of most organic substanc es and produced a considerable amount (almost 3%) of lysozyme-enriched usef ul biomass.