Sampling from the soil that rich of cholesterol, five strains were obtained through concentration and cultivation on the screen culture in which the cholesterol was the unique carbon source. The highest-production strain was identified and the culture conditions were optimized. The result indicated that the highest-producing strain belonged to P. guilliermondii. The optimal medium was: starch maize 0.7％, yeast extract paste 1.5％,cholesterol 0.2％, tween 80 1％ .The optimal culture condition was: pH7.5, aeration 75mL culture/250mL flask,cultured 48 hours at the temperature of 37℃.Under the optimal cultivation condition, the activity of cholesterol oxidase raised at 3501 U/L,improved 1.5 times higher than before.%从富含胆固醇环境的土壤等中进行采样,经富集培养后,以胆固醇为单一碳源的筛选培养基进行筛选,得到不同形态的5株菌株.挑选产酶量最高的一株进行菌种鉴定,并对其发酵产酶条件进行优化.结果表明,该高产胆固醇氧化酶菌株属于季也蒙毕赤酵母属(P.guilliermondii).其最适发酵培养基组成为:玉米淀粉0.7%,酵母膏1.5%,胆固醇0.2%,吐温801%;理想的培养条件为:培养基pH7.5,37℃条件下培养,装液量为75mL于250mL三角瓶中.优化发酵条件后产酶量达到3501U/L,比发酵前提高了1.5倍.
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