用近紫外线和氯化锂复合选育柔红霉素产生菌——天蓝淡红链霉菌(S. Coeruleorubidus)高产株的研究

本文首次报道了用近紫外线(NUV)与LiCl复合选育柔红霉素产生菌--天蓝淡红链霉菌(S. Coendeorubidus)的实验结果.实验获得一株柔红霉素高产突变株,在发酵罐上应用,柔红霉素产率比出发菌株高10%.     

柔红霉素产生菌SIPI-1482中dnmV基因功能的阻断及恢复

dnmV基因产物为柔红霉素生物合成途径中TDP-6-脱氧己糖C4酮基还原酶,破坏该基因能阻断柔红糖胺的合成,进而阻断柔红霉素的产生。从天蓝淡红链霉菌(S. coeruleorubidus)SIPI-1482基因组DNA中经PCR扩增出dnmV及其上游dnmU基因片段,并由此构建了用于阻断dnmV基因的同源重组质粒pYG817,转化SIPI-1482菌株后成功地破坏了dnmV基因,发酵结果显示阻断突变株不再代谢产生柔红霉素,为引入新的基因来改变代谢产物的糖基结构打下了基础。通过导入dnmV基因表达质粒可重建该突变株的生物合成途径,恢复产生柔红霉素,但产量比出发菌株要低。     

用紫外线和耐柔红霉素及其复合诱变一株天兰淡红链霉菌HM1482

柔红霉素是半合成表阿霉素等低毒高效抗癌药物的重要原料。用紫外线和耐柔红霉素及其复合诱变柔红霉素产生菌—天兰淡红链霉菌ＨＭ1 4 82的诱变效果 ,曾获一株高产诱变株 1 4 82 -77,在生产罐中应用 ,其柔红霉素产率较出发菌株提高 1 2 2 .6%。材料与方法 :①斜面与分离平皿培养基主要成份为可溶性淀粉、天冬素、Ｋ2 ＨＰＯ4 和琼脂等。②种子与发酵培养基主要成份为玉米粉、黄豆粉、葡萄糖、碳酸钙及微量(ＮＨ4 ) 2 ＳＯ4 、Ｋ2 ＨＰＯ4 等。产率 (效价 )测定采用ＴＬＣ、ＨＰＬＣ ,主要实验数据见表 1。　　　表 1　　产率测定数据表　　…     

应用原生质体技术选育天兰淡红链霉菌

本文报道柔红霉素产生菌——天兰淡红链霉菌原生质体的制备和再生方法,并从再生菌落中筛选得到摇瓶发酵单位提高５％的高产菌株３０＃。将再生高产株经铜蒸气激光辐照,得到在生产罐中发酵水平比对照出发菌株提高１２．９％的高产菌株８２＃。     

医院病人携带的金黄色葡萄球菌耐药性研究

本文报道1982—1990年从南京地区三所医院病人分离的296株金黄色葡萄球菌耐药性检测结果。发现8年间对红霉素、氯霉素和链霉素的耐药率均非常显著地上升(P<0.01).0—4耐药株比例逐年下降(P<0.01)。5耐以上的菌株呈逐年上升趋势。不同医院菌株对红霉素和卡那霉素的耐药率存在显著性差异(P<0.05)。对氯霉素、红霉素、庆大霉素、卡那霉素和链霉素的耐药率接近或高于革兰氏阴性菌,对其余几种抗生素的耐药率均显著低于革兰氏阴性菌(P<0.01),但也达到50.     

天蓝淡红链霉菌SIPI-1482的dauW基因的克隆及在大肠杆菌中的表达

克隆得到了柔红霉素产生菌天蓝淡红链霉菌(Streptomyces coeruleorubidus) SIPI-1482位于dnrX下游的新基因dauW,其位于基因组上dnrX和drrB之间,GenBank中Blast发现它与dnrW有较高的同源性,将其命名为dauW,并提交GenBank获得登录号EF523565,根据保守域推测dauW所编码的蛋白属于FAD依赖的氧化还原酶类。将dauW分别克隆至表达载体pET-28a(+)、pET-32a(+),在宿主菌BL21(DE3)中经IPTG诱导后,实现了在大肠杆菌中的表达。初步实验表明dauW在BL21(DE3)中的表达能增加宿主对柔红霉素的抗性,可能与天蓝淡红链霉菌对柔红霉素的自身抗性有关。     

红霉素链霉菌的溶源转换研究

2-62菌株是一溶源性菌株,合成红霉素能力稳定,气生菌丝生长良好。经42℃培养后筛选得到的4株无活性菌株(Em-)便不再释放噬菌体,成为去溶源菌株,并对P4噬菌体敏感。当此菌株再次溶源化后,又恢复了合成红霉素的能力,表明p4噬菌体与红霉素产生密切相关。 经诱变获得的1-9及10-25Em-菌株,气生菌丝生长受抑制,呈光秃型,经连续传代20次仍保持菌落类型纯一。当1-9及10-25菌株成为1-9(P4)及10-25(P4)时,选择恢复气生菌丝生长的菌落用琼脂块法测定,均获得产生红霉素的性能,并都释放噬菌体。说明P4噬菌体具有溶源转换的性能,它与红霉素的生物合成及气生菌丝的形成等性状相关。     

柔红霉素在人敏感和抗三尖杉酯碱的HL－60细胞中分布和积聚变化

应用激光扫描共焦显微镜和流式细胞术,研究柔红霉素在人敏感和抗三尖杉酯碱的ＨＬ－６０细胞中分布和积聚变化。柔红霉素１０μｇ／ｍｌ处理细胞１小时,激光扫描共焦显微镜观察到：在敏感ＨＬ－６０细胞中,柔红霉素主要分布于细胞核中;而在抗性细胞中,主要分布于细胞一侧。逆转抗药性的药物维拉帕米不改变柔红霉素在抗性细胞中的核质分布。流式细胞术显示：三尖杉酯碱和蛋白激酶Ｃ激活剂佛波脂处理细胞,使柔红霉素在抗性细胞内积聚降低;而粉防己碱和维拉帕米处理细胞１小时,柔红霉素在抗性细胞内积聚明显增加,但维拉帕米处理２４小时,反而使积聚降低。结果表明：抗三尖杉酯碱的ＨＬ－６０细胞改变桑红霉素的胞内分布,降低细胞内的积聚是抗药性的机制之一。     

提高表柔比星质量与生产水平的研究

柔红霉素产生菌S．Coeruleorubidus经N^ 、Co^60理化诱变剂选育后,获得的高产菌株经发酵罐应用后,其发酵产率分别提高25．8％、17．6％,累计净增利润超亿元,经分离收集的活性生物精品制成表柔比星,纯度提高4％,杂质比例下降2倍以上,收率提高50％,符合最新国际权威药典标准,产品畅销世界。     

在红霉素糖多孢菌的染色体上整合含eryCl基因的染色体DNA片段可提高红霉素产量

红霉素糖多孢菌(Saccharopolyspora eryth-raea)产生的红霉素A(ErA)是一种广谱大环内酯抗生素。其中eryC1基因可能与红霉素产生的调节有关。如果在野生型菌株的染色体上另外整合一段包括eryC1基因在内的DNA片段,可能提高红霉素A的产量。     

耐温谷氨酸棒杆菌的选育及其高温谷氨酸发酵代谢流量分析

采用基因组改组的方法选育获得的一株耐温谷氨酸棒杆菌F343,并比较了F343与其出发菌株S9114在39℃发酵谷氨酸时的发酵特性和代谢流量。结果表明:耐温菌F343的比生长速率、比谷氨酸积累速率可维持在较高的水平;通过发酵中后期代谢流量分析发现耐温菌F343在磷酸烯醇式丙酮酸(PEP)节点处,磷酸烯醇式丙酮酸羧化酶(PEPc)催化的CO_2回补支路反应代谢流增加;α-酮戊二酸(KG)节点处,谷氨酸氢酶(GDH)催化的产生谷氨酸的支路代谢通量增加。此外,高温发酵谷氨酸时,耐温菌F343高温发酵谷氨酸过程产生的乳酸等副产物较出发菌株S9114少。通过改善种子质量,F343在高温发酵30 h产酸达到10.1%,较出发菌株提高67%。     

Potential of solid state fermentation for production of ergot alkaloids

Production of total ergot alkaloids by Claviceps fusiformis in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of Claviceps purpurea but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids.     

Microbiological,rheological and aromaticcharacteristics of fermented Uji (an East African Sour Porridge)

Three methods for fermentation of uji were compared in laboratory trials: spontaneous, backslopping (using an inoculum from a previous fermentation) and use of a starter culture of lactic acid bacteria. Spontaneous fermentation resulted in the slowest decrease in pH, while the use of starter culture led to the lowest final pH (3.5). Coliforms were eliminated in less than 8 h using backslopping or starter culture, but increased in numbers during spontaneous fermentation. The viscosity of uji was only marginally affected by the method of fermentation. The aroma profile following spontaneous fermentation contained esters with fruity notes and ethanol and higher alcohols, while mainly organic acids was produced by fermentation with the starter culture. Backslopping led to the lowest production of almost all volatiles identified.     

微生物法生产二羟基丙酮的研究进展

以下综述了微生物发酵法制备二羟基丙酮的研究进展。利用微生物发酵法生产二羟基丙酮比化学合成法具有更大的优势,氧化葡萄糖酸杆菌是二羟基丙酮工业发酵生产中最有应用价值的菌株。发酵过程中底物、产物、氧气、菌体量等各种因素都会对二羟基丙酮产量产生影响,在各种发酵方式中反复流加工艺和固定化发酵工艺最有前途。重组菌株的构建和发酵工艺的优化是将来微生物发酵生产二羟基丙酮的发展方向。     

种间双亲灭活原生质体融合选育高产Monacolin K红曲菌

为获得高产MonacolinK的红曲菌菌株,将经农杆菌介导转化获得的携带潮霉素抗性基因且以甘油为原料液态发酵高产MonacolinK的发白红曲菌H2和以大米为原料固态发酵产Monaco-1inK的烟色红曲菌9908作为亲本,对其原生质体分别进行热灭活及紫外灭活,然后对灭活双亲用PEG作融合剂进行原生质体融合。从融合子中选出有潮霉素抗性的突变株,通过发酵与亲本对比,筛选得到一株以大米为原料固态发酵高产MonacolinK的融合株F12．11,其MonacolinK产量达到8．73mg／g;较发白红曲菌H2与烟色红曲菌9908分别提高了100．23％和48．98％;一株以甘油为原料液态发酵高产MonacolinK的融合株F13-2,其MonacolinK的产量达到1752．46mg／L,较发白红曲菌H2与烟色红曲菌9908分别提高了32．98％和1979．33％。     

蛹虫草菌胞外多糖发酵及其发酵动力学

蛹虫草菌(Cordyceps militaris)胞外多糖(EPS)的发酵过程和发酵动力学进行了研究。基于Logitic方程和Luedeking-Piret方程,得到了描述发酵过程的动力学数学模型和模型参数,同时对实验数据与模型进行了验证比较。模型计算与实验结果拟合良好,模型正确地反应了蛹虫草菌胞外多糖的发酵过程及其动力学机制。     

Production of Botrytis cinerea for potential introduction into a vineyard

Botrytis cinerea was produced in solid-phase fermentation, liquid fermentation and on potato dextrose agar. Stored products were evaluated for grape colonization in grape bioassays and in field trials, and for B. cinerea density using colony forming unit analyses and a nucleic-acid-based method. B. cinerea colony forming unit density was significantly correlated to the probability of successful grape colonization in grape bioassays (p-value=0.0002). Solid fermentation products could be stored longer than liquid fermentation and potato dextrose agar products. There was little difference in the rate of grape colonization in laboratory bioassays among solid-phase fermentation, liquid fermentation and plate culture products. Although the initial B. cinerea colonization rate of field grapes was slightly greater on vines treated with solid-phase fermentation and plate culture products compared to vines treated with product from liquid fermentation, there was no significant difference in final colonization between vines treated with solid-phase fermentation, liquid fermentation and plate culture products and untreated vines.     

Observations on a Laboratory Method for Submerged Acetic Fermentation

Submerged acetic fermentation experiments were performed for the purpose of determining the conditions under which this type of fermentation should be conducted under laboratory conditions. The apparatus used consisted of a set of glass tubes provided with air spargers.

Acetobacter acetigenum was found to be the most suitable bacterium among six Acetobacter compared under submerged acetic fermentation conditions in a synthetic medium. Statistically significant different rates of fermentation were observed in acetators that were identical in construction, fermentation medium, and aeration characteristics.

Extremely long growth lag periods and complete absence of growth were often observed when starting fermentations. The causes of this behavior were investigated. It was found that it was not produced by lack of nutrients or by presence of a bacteriophage. Different kinds of bacterial starters were studied and compared. Cultures maintained in a liquid medium were reliable starters with a short growth lag period. Liquid medium cultures maintained their good starter characteristics after periods of storage of up to 11 weeks at 40 F (4 C).

     

响应面分析优化L-色氨酸清液发酵培养基

L-色氨酸是八种必需氨基酸之一,随着L-色氨酸应用市场的不断扩大,进行发酵法生产L-色氨酸的研究具有重要的现实意义。为了提高L-色氨酸产量,本文利用响应面分析法对L-色氨酸清液发酵培养基进行优化。利用优化培养基进行发酵,考察清液发酵对L-色氨酸发酵过程中生物量、L-色氨酸产量、副产物生成量的影响。结果表明:在优化条件下利用清液发酵培养基发酵,乙酸含量与原工艺相比降低了(6.75±1.26)%,L-色氨酸产量提高了(16.54±1.15)%,实验值与响应面分析预测值基本相符。     

Use of Cheese Whey for Vitamin B12 Production: III. Growth Studies and Dry-Weight Activity1

The patterns of growth and vitamin formation by Propionibacterium shermanii in whey were similar to the patterns established in other substrates. The vitamin formation was observed during the latter part of the fermentation after the organism approached maximal growth. Lactose utilization by the organism corresponded to the logarithmic-growth phase of the organism. Analyses of the dried culture showed a large increase of vitamin B(12) in the fermentation solids compared with unfermented dried whey. A feed analysis showed a notable increase of protein and a large decrease in nitrogen-free extract of the dried fermentation solid compared with dried whey.