本研究旨在利用微生物对熊果酸进行生物转化,以期对其结构进行修饰。首先从六种枇杷叶中筛选内生菌，将筛选到的内生菌对熊果酸进行转化实验，其中窄叶、解放钟和茂木三种枇杷叶中分离到的枇杷叶内生菌1对熊果酸有明显转化作用，并得到萜类物质；其次利用金龟子绿僵菌和熊果酸的共同发酵培养得到一种白色针状晶体，它的熔点为202~205 ℃，高温易溶于甲醇，并对此晶体的结构进行了初步研究。

This research studied the transformation of ursolic acid by some microorganism in order to modify its structure. Through the incubation of ursolic acid with the endophytic fungus isolated from six different kinds of loquat leaves, the loquat leaf endophytic fungus1 founded in loquat leaf Narrow leaf, Jiefangzhong and Mogi can transform the ursolic acid to a Terpenoid compound. By incubation of ursolic acid with metarhizium anisopliae, a acicular crystal was obtained with the melting point being of 202~205 ℃ and high solubility in methanol. The crystal was then preliminarily analyzed.