【摘要】 将含有去掉启动子的枯草杆菌碱性蛋白酶基因和Ｃｍ抗性基因的整合质粒ｐＭＰ以原生质体ＰＥＧ法转化Ｂ．ｌｉｃｈｅｎｉｆｏｒｍｉｓ２７０９，在１０ｕ／ｍｌＣｍ平板上筛选整合子，并通过不断提高整合子的抗氯霉素能力来扩增染色体碱性蛋白酶基因，最终选到一株产酶比生产菌２７０９提高６０％的高表达整合菌ＢＬ－２０３，该菌在无选择压力下遗传性状相当稳定。更多还原

【Abstract】 y constructing an integration plasmid pMP,the alkaline protease gene lacking promotor and Cm resistance gene from pC194 were integrated into the genome of Bacillus licheniformis 2709 using PEGtreated protoplast transformation.The integraton strains were selected with 10 u/ml Cm.Then the alkaline protease gene amplification was performed by the increasement of the Cm resistance.A high expression strain BL203 was obtained.Compared with the parent,the amount of alkaline protease produced by it increased by 60 percent without selection pressure.更多还原