In order to screen a high⁃yielding phospholipase D strain from Streptomyces sp. LD0501, we studied the conditions for its protoplasts′preparation and regeneration, and mutagenized its protoplasts by UV radiation as well. The protoplasts were prepared by enzyme and mutagenized with UV irradiation. The mutation result was determined by TLC. The optimum conditions for the preparation of the protoplasts were as follows:the Streptomyces LD0501 was inoculated into mycelia medium with 0�5% glycine and cultured for 72 h�The mycelia were processed with 3 mg/mL lysozyme at 30℃ for 75 min. Protoplasts of Streptomyces sp. LD0501 were induced by UV radiation to obtain a high phospholipase D⁃producing strain,whose phospholipase D′s enzyme activity reached 4�29 U/mL, increased by 180�4% compared with the initial strain. The method improved the preparation effect of protoplasts from Streptomyces LD 0501 effectively and enhanced phospholipase D strain′s vitality greatly by UV irradiation of the protoplasts,the production of the high⁃yielding mutant strain was verified to be genetically stable.%为了获得磷脂酶D高产菌株，由链霉菌野生菌株LD0501出发研究原生质体的制备和再生条件，建立原生质体紫外诱变筛选方案。采用酶解法制备原生质体，用紫外线对原生质体诱变，TLC检测突变株产磷脂酶D活力。原生质体的适宜条件：种子培养基中甘氨酸质量浓度5 g／L，菌龄72 h，用3 mg／mL的溶菌酶在30℃下酶解75 min。通过原生质体诱变筛选，得到1株高产菌株，磷脂酶D水解活力达4�29 U／mL，提高幅度为180�4％。该方法有效改善了链霉菌野生菌株原生质体的制备效果，紫外诱变筛选显著提高了磷脂酶D的活力，高产突变株具有较好的稳定性。
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