[目的]以产酸性α-淀粉酶菌解淀粉芽孢杆菌B-5为出发菌株,通过对B-5原生质体进行紫外线诱变以达到提高产酸性α-淀粉酶活力的目的.[方法]在溶菌酶浓度为20 mg/ml,37℃酶解90 min条件下,原生质体制备率达到94%.然后经紫外线诱变处理,从中筛选水解圈与菌落比值较大者进行发酵,测定酸性α-淀粉酶活力.[结果]从大量突变菌株中筛选得到1株α-淀粉酶活力为267 U/ml的突变菌株UV-329,其产酶活力较出发菌株B-5提高了254.2%.[结论]利用紫外线对解淀粉芽孢杆菌B-5原生质体进行诱变是一种有效的微生物育种方法.%[ Objective ] Bacillus amyloliquefaciens 5 was used as initial strain for preparation of protoplast and UV-mutagenesis in order to promote its acid ct-amylase production. [ Method] The preparation rate of protoplast could reach 94％ with 20 mg/ml of lysozyme by enzymolysising for 90 min at 37 ℃. The mutant with the bigger ratio of hydrolyzation circle diameter to bacterial colony diameter was screened after UV mutagenesis so as to assay acid α- amylase activities. [ Result] Mutant UV-329 with acid α-amylase activity of 267 U/ml was screened from a lot of mutants, with an increase of 254.2％ over that of the initial strain. [ Conclusion] UV mutagenesis for protoplast was an effective breedlng method.
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