Method for degrading phytosterol to synthetize androstane-4-ene-3,7-dione through mycobacteria

The invention relates to a method for degrading phytosterol to synthetize androstane-4-ene-3,7-dione through mycobacteria. A basic culture medium is involved and comprises, by mass, 14-18% of sunflower oil, 1.0-1.2% of phytosterol, 2-4% of molasses, 3-5% of corn starch, 0.25-0.30% of NH4NO, and 0.10-0.15% of K2HPO4. The method comprises the steps that mycobacteria are inoculated to the basic culture medium and then cultured at 30-32 DEG C for 4-7 days. According to the method, the defects are fundamentally overcome that through a diosgenin method for producing steroid medicine, many steps areneeded, the yield is low, and the price is high. Resource advantages can also be sufficiently used and developed, and the situation is avoided that due to dioscorea nipponica supply, raw material sources are constrained by natural factors such as seasons and regions; in addition, a certain effect is achieved on protection of natural resources and ecological environments and maintenance of human health. 种利用分枝杆菌降解植物甾醇合成雄甾-4