为了开发丙酮酸高产菌株,以大肠杆菌MG1655为出发菌株,通过基因敲除阻断副产物途径构建了产丙酮酸大肠杆菌工程菌KLPP。进一步利用p UT Mini-Tn5载体进行转座子随机突变,构建了含有7 197个单克隆的突变体文库。使用基于丙酮酸的二硝基苯肼显色法,建立了96孔板-酶标仪快速筛选方法,经过两轮的筛选,成功筛选到了6个突变体菌株,比KLPP丙酮酸产量提高了38%、31%、19%、28%、44%和14%。利用全基因组重测序确定了其转座子插入的位置,进而确定了可能影响丙酮酸产量的基因位点,为后续菌株改造工作奠定了基础。
[Objective] The aim was to detect effects of biochar on soil enzyme activity and mechanism. [Method] Soils were sampled from experimental fields of Shanxi Academy of Agricultural Sciences and added with charcoals in different types in order to analyze dynamic changes of alkaline phosphatase and cellulase activities and effects of charcoals on soil enzyme activities. [Result] By applying charcoal, enzyme activity of soil samples all improved and the increase degree was higher of alkaline phosphatase than cellulase activity. Mid-temperature charcoal at 8% is the best. [Conclusion] The research provides references for effects of biochar on physi- cal and chemical properties.
