利用核桃种皮纯多糖WKPP-70-1-1，以大肠杆菌为供试菌，通过分析不同浓度下WKPP-70-1-1对大肠杆菌的作用，确定其最小抑制浓度MIC为400 μg/mL。又通过对MIC下大肠杆菌的生长曲线的分析研究，确定WKPP-70-1-1对大肠杆菌的作用是抑制而不是杀死，而且其抑制时间集中在对数生长期，到一定时间WKPP-70-1-1对大肠杆菌的抑制作用会解除，最后对WKPP-70-1-1作用大肠杆菌菌体先后形态做了原子力显微镜的观察，结果表明WKPP-70-1-1作用大肠杆菌后，原本光滑无褶皱的菌体变得褶皱，粗糙，失去了规则形态结构。

The antimicrobial effect of pure polysaccharide from walnut kernel pellicle (WKPP-70-1-1) with different concentration on E.coli was studied and its minimum inhibitory concentration (MIC) was determined as 400 μg/mL. Analysis of growth curve of E.coli effected by MIC of WKPP-70-1-1 showed that WKPP-70-1-1can inhibit the growth of E.coli, especially the logarithm phase of E.coli. After a certain time, the inhibition effect of WKPP-70-1-1 might disappear. The morphology of E.coli treated by WKPP-70-1-1 was observed by Atomic force microscopy and the results showed that smooth and no-wrinkle E.coli became wrinkles, rough, loss of the rules of morphology.