费氏链霉菌HTP6分批发酵动力学

对费氏链霉菌HTP6产新霉素的分批发酵动力学进行了研究, 并建立了动力学模型。对数生长期最大比生长速率μm为0.0866 h-1, 产物合成期最大合成速率qp为1.1867×10-4 g/(mL×h)。对实验数据与模型模拟值进行拟合检验, 表现出很好的适用性, 实验平均相对偏差小于5%。表明该动力学模型对费氏链霉菌产新霉素的发酵生产具有实际意义。     

复合诱变选育绿色产色链霉菌抑菌高活性菌株

以一株绿色产色链霉菌xzte06菌株为出发菌株,依次通过软X射线、低能离子束诱变、紫外线照射和微波诱变手段对菌株进行复合诱变,得到一株对产气荚膜梭状芽胞杆菌具有较强抑制活性的菌株W26菌株,且该菌株的遗传特性稳定。对菌株进行抑菌试验发现,该菌株液体深层发酵菌丝体的内酮提取物的抑菌活性与出发菌株相比提高了101.42%。     

HNO_2诱变选育链霉菌702菌株

以链霉菌702-20为出发菌株,经HNO2诱变处理,获得高产突变株。实验结果表明:HNO2处理20 m in对菌株的致死率可达83.10%,突变率高达14.13%,经过摇瓶筛选获得高产突变株20-29-148,产链霉素能力达到1.404 mg/mL,比出发菌株提高了37.65%。经传代培养考察,该突变菌株具有良好的遗传稳定性。     

南昌链霉菌的微波诱变

以微波对南昌链霉菌进行了微波育种,获得梅岭霉素杀虫剂生产能力高于出发菌株73％的W4-311。该菌株经多次传代,遗传性状保持稳定。     

盐增强培养对弗氏链霉菌产新霉素的影响

目的:弗氏链霉菌(Streptomyces fradiae)作为氨基糖苷类抗生素新霉素的主要生产菌株,其新霉素B具有抗菌活性强、抗癌、抗HIV等作用,提高新霉素B的效价具有重要意义.方法:在满足微生物正常生长所需盐离子的条件下,通过盐增强培养的方式向培养基中添加不同种类、浓度无机盐来改变细胞壁附近的理化特性、渗透压以及...     

阿维链霉菌的诱变育种

以阿维链霉菌(Streptomyces avermitilis)76-12为出发菌株,采用亚硝基胍、吖啶橙、紫外线和氯化锂分别对其孢子和原生质体进行诱变,经抗代谢物理性筛选,获得一系列高产突变株,其中N-1-2高产突变株的发酵单位是出发菌株的2.47倍。实验中同时获得了只产阿维菌素a组分的突变株G-32、Bla组分含量高的Ave8菌株和产蓝绿色孢子的突变株UA-G等。     

链霉菌LA5高产菌株诱变育种研究初报

抗生素LA5具有开发成抗真菌农用抗生素的广阔前景,但由于该菌株的野生型菌株发酵效价低,不能满足工业化开发的要求。通过以链霉菌LA5为出发菌株,采用紫外线(UV)、微波、亚硝基胍(NTG)、紫外线 亚硝基胍、亚硝基胍 紫外线等方法进行诱变筛选,结果表明,以紫外线照射80 s 亚硝基胍处理80 min的诱变的正突变率最高,为30%,其他依次为亚硝基胍处理80 min 紫外线照射40 s诱变和亚硝基胍处理60min 紫外线照射120 s诱变,正突变率均为26%。然后依次使用亚硝基胍处理80 min 紫外线照射80 s、亚硝基胍处理80 min 紫外线照射40 s、亚硝基胍处理60 min 紫外线照射120 s进行第2、第3、第4轮复合诱变筛选,最后选育出突变菌株U8-N8A-196,其产抗生素能力比链霉菌LA5出发菌株提高了34.5%,极显著高于LA5菌株。     

链霉菌6803菌株对植物的化感作用

链霉菌属是绝大多数已知抗生素和一些重要活性物质的产生菌,它对高等植物是否具有化感作用尚缺乏研究.从土壤中分离获得7个放线菌菌株,研究其对植物幼苗生长的抑制作用.结果表明:链霉菌6803菌株在固体和液体发酵培养时均强烈抑制油菜根和稗草根的生长,其液体发酵液的5倍稀释液对油菜和稗草苗生长的抑制分别达到60.7％和61.3％.常规形态与生理生化试验表明,该菌株属于链霉菌属金色类群;16S rRNA基因序列分析表明,该菌株为沙场链霉菌,基因序列相似性达到99.28％.此菌株经过80 ～ 100 s紫外线照射筛选出的正突变菌株UV8024和UV100-2的10倍稀释发酵液对油菜幼苗生长的抑制作用比原始菌株分别提高了37.5％和38.1％,经过1％硫酸二乙酯诱变50 min筛选出的正突变菌株D507的10倍稀释发酵液对油菜幼苗生长的抑制作用比原始菌株提高了29.8％.链霉菌6803菌株对高等植物具有化感作用,并可通过诱变育种提高其化感潜力.     

几种诱变因子对龟裂链霉菌原生质体的影响

作者应用通电、ＵＶ、ＮＴＧ和亚硫酸氢钠等诱变因子对土霉素产生菌——龟裂链霉菌１３８—ｌ原生质体进行处理。结果表明,各种诱变因子在对原生质体致死率５０％左右时具有较好的诱变效应。经亚硫酸氢钠＋ＬｉＣｌ处理获得的Ｃｌ１８菌株通过１６５００１发酵罐试验,最高发酵水平达３３３３０ｕ／ｍｌ,平均发酵水平为３０５４２．５ｕ／ｍｌ,比出发菌株１３８—１提高２０．６％。     

Production of tylosin in solid-state fermentation by Streptomyces fradiae NRRL-2702 and its gamma-irradiated mutant (γ-1)

Aims:  To develop solid-state fermentation system (SSF) for hyper production of tylosin from a mutant γ-1 of Streptomyces fradiae NRRL-2702 and its parent strain.
Methods and Results:  Various agro-industrial wastes were screened to study their effect on tylosin production in SSF. Wheat bran as solid substrate gave the highest production of 2500 μg of tylosin g⁻¹ substrate by mutant γ-1 against parent strain (300 μg tylosin g⁻¹ substrate). The tylosin yield was further improved to 4500 μg g⁻¹ substrate [70% moisture, 10% inoculum (v/w), pH 9·2, 30°C, supplemental lactose and sodium glutamate on day 9]. Wild-type strain displayed less production of tylosin (655 μg of tylosin g⁻¹ substrate) in SSF even after optimization of process parameters.
Conclusion:  The study has shown that solid-state fermentation system significantly enhanced the tylosin yield by mutant γ-1.
Significance and Impact of the Study:  This study proved to be very useful and resulted in 6·87 ± 0·30-fold increase in tylosin yield by this mutant when compared to that of wild-type strain.     

Change in colony morphology and kinetics of tylosin production after UV and gamma irradiation mutagenesis of Streptomyces fradiae NRRL-2702

Tylosin is a macrolide antibiotic used as veterinary drug and growth promoter. Attempts were made for hyper production of tylosin by a strain of Streptomyces fradiae NRRL-2702 through irradiation mutagenesis. Ultraviolet (UV) irradiation of wild-type strain caused development of six morphologically altered colony types on agar plates. After screening using Bacillus subtilis bioassay only morphological mutants indicated the production of tylosin. An increase of 2.7±0.22-fold in tylosin production (1500 mg/l) in case of mutant UV-2 in complex medium was achieved as compared to wild-type strain (550 mg/l). Gamma irradiation of mutant UV-2 using ⁶⁰Co gave one morphologically altered colony type γ-1, which gave 2500 mg/l tylosin yield in complex medium. Chemically defined media promoted tylosin production upto 3800 mg/l. Maximum value of q_p (3.34 mg/gh) was observed by mutant γ-1 as compared to wild strain (0.81 mg/gh). Moreover, UV irradiation associated changes were unstable with loss of tylosin activity whereas mutant γ-1 displayed high stability on subsequent culturing.     

铜蒸气激光及其与氯化锂复合选育龟裂链霉菌的研究

本文首次报导有关铜蒸气激光及其与氯化锂复合选育龟裂链霉菌的研究。在相同的实验条件下，铜蒸气激光辐照龟裂链霉菌比其随后又氯化锂复合处理的效果好。     

超声波诱变选育乳链菌肽(Nisin)高产菌株

目的：从乳酸乳球菌中选育Nisin高产菌株。方法：利用超声波对乳酸乳球菌进行诱变,并用琼脂扩散法检测其效价。结果：获得一突变菌株S-1,该菌株的生物效价为343.53IU/mL,比原始菌株提高31.52%。结论：突变株S-1遗传性能稳定,为进一步菌种选育奠定基础。