1问题李金安人教版高中《生物·选修1·生物技术实践》P.18的标题是“(二)纯化大肠杆菌”。究竟什么是细菌的纯化?怎样纯化大肠杆菌?2讨论李传海[北京市大兴区第一中学(102600)]首先,自然界中微生物无处不在,保存的菌种很容易被污染。其次,微生物繁殖快,很容易发生突变。由于以上两个原因,保存的大肠杆菌菌种很容易变得不纯,或者由于长期保存等原因导致其生活力下降。因 1 Questions Li Jin’an PEP Senior High School “Biology · Elective 1 · Biotechnology Practice” P.18 is titled “Purification of Escherichia coli”. What is the purification of bacteria? How to purify E. coli? 2 Discussion Li Chuanhai [Beijing Daxing District First Middle School (102600]] First of all, microorganisms in nature are ubiquitous, the preservation of bacteria is easily contaminated. Second, microorganisms multiply fast and are prone to mutation. For these two reasons, E. coli strains that are stored can easily become impure, or their viability can be compromised by long-term storage and the like. because