产蓝色素放线菌的初步鉴定和蓝色素性质研究

对一株从土壤中筛选出来的产蓝色素的放线菌进行了初步鉴定, 命名为天蓝色链霉菌－１００（Ｓｔｒｅｐｔｏｍ ｙｃｅｓ ｃｏｅｌｉｃｏｌｏｒ－１００ ）,并对蓝色素的性质进行了研究．结果表明此色素无臭无味,水溶性较强．酸性条件下,溶解度随ｐＨ 降低而减小．ｐＨ＜ ８ 时为红色,ｐＨ≥８ 时为蓝色,颜色随ｐＨ 增大而加深．于１００ ℃短时间处理,比较稳定．在ｐＨ 中性的条件下对光（包括紫外光）较稳定．大多数金属离子如Ｂａ２＋ 、Ｋ＋ 等对此色素无影响,Ｍｇ２＋ 使色素增色．Ｆｅ２＋ 在５×１０－４ ｍ ｏｌ／Ｌ时,使色素变性,但在５×１０－５ ｍ ｏｌ／Ｌ时,对色素没有多大影响．Ｐｂ２＋ 可以络合色素,使之沉淀;加入０．２５％ 盐酸乙醇后,色素再溶解．该蓝色素可作为天然色素或天然ｐＨ 指示剂开发．     

Zinc uptake by Streptomyces rimosus biomass using a packed‐bed column

The ability of Streptomyces rimosus biomass to bind zinc ions in batch mode was shown recently. The aim of this study was to determine the zinc uptake capacity by Streptomyces rimosus biomass in continuous mode. Bacterial biomass was able to bind more Zn(II) after pretreatment with sodium hydroxide (1 mol dm⁻³) than without treatment. The maximum adsorption capacity and the adsorption capacity at the saturation point calculated by means of both the exchange zone model and the Thomas model were practically identical of about 2.9 mg_Zn(II) g⁻¹_biomass. This result was lower than the batch adsorption capacity of Streptomyces rimosus, indicating that the packed‐bed is not the most appropriate process to exploit the bacterial biomass adsorption capacity. The effect of zinc concentration in the range of 10 to 200 mg_Zn(II) dm⁻³ on the biosorption capacity of the packed‐bed was not significant. Biomass regeneration with 0.1 mol dm⁻³ HCl gave a 90% recovery of the adsorbed Zn(II). © 1999 Society of Chemical Industry     

发酵法生产利普司他汀的研究进展

利普司他汀（lipstatin）是一种β-内酯分子,能选择性抑制胰脂肪酶的活性,从而减少小肠脂肪的吸收。分析表明,一个利普司他汀分子与一个脂肪酶分子结合,通过活性部位丝氨酸残基的酰化来抑制胰脂肪酶的催化活性。利普司他汀由毒三链霉菌（Streptomyces toxytricini,简称S. toxytricini）生产的一种天然产物。本文综述了利普司他汀的结构特点,分析了利普司他汀市场应用现状,着重论述了发酵法生产利普司他汀的研究进展;提出生物合成利普司他汀的机制尚不清楚,但酰基辅酶A羧化酶（ACCase）复合物在利普司他汀生物合成中起着关键作用。最后,指出当前存在的问题并对代谢工程在利普司他汀产生菌发酵中的应用进行概述,对今后的研究趋势进行了展望。     

Characterization of Class V DyP-Type Peroxidase SaDyP1 from Streptomyces avermitilis and Evaluation of SaDyPs Expression in Mycelium

DyP-type peroxidases are a family of heme peroxidases named for their ability to degrade persistent anthraquinone dyes. DyP-type peroxidases are subclassified into three classes: classes P, I and V. Based on its genome sequence, Streptomyces avermitilis, eubacteria, has two genes presumed to encode class V DyP-type peroxidases and two class I genes. We have previously shown that ectopically expressed SaDyP2, a member of class V, indeed has the characteristics of a DyP-type peroxidase. In this study, we analyzed SaDyP1, a member of the same class V as SaDyP2. SaDyP1 showed high amino acid sequence identity to SaDyP2, retaining a conserved GXXDG motif and catalytic aspartate. SaDyP1 degraded anthraquinone dyes, which are specific substrates of DyP-type peroxidases but not azo dyes. In addition to such substrate specificity, SaDyP1 showed other features of DyP-type peroxidases, such as low optimal pH. Furthermore, immunoblotting using an anti-SaDyP2 polyclonal antibody revealed that SaDyP1 and/or SaDyP2 is expressed in mycelia of wild-type S. avermitilis.     

金褐霉素高产相关基因的筛选与表达

通过高效表达金褐霉素生物合成基因簇中的调控基因来提高其产量。本实验从野生金褐链霉菌SYAU0709克隆aurJ3M基因,连接载体pMD19-T并测序。将带有aurJ3M基因的表达质粒pBJAUM转化金褐链霉菌SYAU0709,高效表达aurJ3M基因,获得重组菌株。通过高效液相色谱分析检测,重组菌株的金褐霉素产量提高约6 倍,并且遗传性能稳定,发酵结果说明过量表达aurJ3M基因能够提高金褐霉素的产量。     

放线菌F8对烟草黑胫病的拮抗作用及其产酶活性

从山东五莲于里黑胫病烟田健康烟株根际土壤分离到一株拮抗放线菌,编号为F8.为了科学评价该菌株在烟草黑胫病生防中的应用潜力,测定了其抑菌活性、产酶活性及控病效果,并通过形态学及16S rDNA序列分析研究其分类地位.结果表明,该菌株对于供试的烟草黑胫病菌具有较强的抑制作用,经无菌滤液处理后的菌丝生长畸形且停滞;该菌株具有几丁质酶、纤维素酶及蛋白酶活性.温室盆栽试验的防治效果显示接种后30 d,F8发酵液对烟草黑胫病的防效为70.3%;根据菌株形态特征、培养特性、生理生化特性及16S rDNA序列分析,鉴定该菌株为链霉菌属不产色链霉菌(Streptomyces achromogenes subsp. streptozoticus).     

一株海洋链霉菌发酵条件的优化及其抑菌活性物质的研究

灰略红链霉菌（Streptomyces griseorubens）F8分离于黄海海岸线沉淀物,通过单因素试验优化其发酵条件,并对其代谢产物及抑菌活性进行研究。结果表明,最佳发酵条件为培养时间11 d、接种量8%、培养温度30 ℃、初始pH值8.0。菌株F8所产抑菌物质对金黄色葡萄球菌（Staphylococcus aureus）,变形杆菌（Proteus）和产气杆菌（Aerobacter aerogenes）具有抑制作用,抑菌圈直径分别为23 mm、34 mm、44 mm,最小抑菌浓度（MIC）分别为100 μg/mL、30 μg/mL、20 μg/mL。菌株F8所产抑菌活性物质的酸碱、热、光照以及遗传稳定性均较好。     

林可霉素工业生产发酵工艺优化

为了提高林可霉素工业生产发酵效价,该研究对林可霉素发酵工艺进行了优化。结果表明,林可霉素最佳发酵条件为二级种子罐发酵培养基中淀粉和黄豆饼粉添加量分别为0.97%和1.43%、延长二级种子移种菌龄至48 h及四级发酵罐基础料计料体积为8 m3。在此优化发酵工艺条件下,林可霉素发酵四级放罐效价高达7 505 U/mL,比原始工艺四级放罐效价提高了16%。初步优化了林可霉素工业生产发酵工艺,提高了林可霉素发酵效能和产量。