Abstract: Disclosed is a microorganism having an excellent ability to convert sterol into and rost-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD), a method for preparation of the microorganism and use thereof, and more particularly, a mutant strain of Mycobacterium fortuitum ATCC 29472, Mycobacterium fortuitum EUG-119, a method for preparation of the mutant and use thereof in preparing AD and ADD. The mutant of the present invention has an excellent ability to convent sterol into AD and ADD which are steroid hormone precursors, compared with the known microorganisms and accordingly, is very useful for mass production of steroid hormones.

Abstract: The present invention relates to a method for preparation of androst-4-ene-3,17-dione (AD) and androsta-1,4-diene-3,17-dione (ADD). More particularly, the present invention relates to a method for preparing AD/ADD, comprising the steps of: (a) heating sterols and emulsifier respectively, to dissolve completely and mixing to prepare a mixture; (b) placing the mixture in a water bath at 70˜90° C. and stirring to obtain emulsified sterols; and (c) adding the emulsified sterols to culture media of microorganism as a component. And the present invention relates to a method for preparing AD/ADD, comprising the addition of cyclodextrin-sterol complexes extracted from milk to culture media of microorganism as a component. The emulsified sterols and cyclodextrin-sterol complexes adopted in the present invention can be easily prepared and be effectively used for obtaining AD/ADD at a high yield.

Abstract: Disclosed are the plant sterol-containing food, and methods for preparing the same. The particle size of the plant sterol contained in the food is nanometer-scale, and the plant sterol-containing food of the present invention inhibits the absorption of cholesterol.