With a purpose to find the most effective way to increase the protein content of beer lees, this paper is focused on the biologic transformation of EM (Effective Micro Organisms) in fermentation. The optimal conditions of transformation are found to be at a temperature of 30℃, with 50% of initial water content and 4 days' ferment under which the net increment of protein is 15%. The basic idea and methods presented here will be valuable for developin...