定向诱变谷氨酸棒杆菌13032产L-鸟氨酸的研究

采用典型的谷氨酸棒杆菌ATCC13032为出发菌,以磺胺胍和氟化钠为双抗性筛选标记,快速定向选育鸟氨酸高产菌。经亚硝基胍-紫外线诱变,获得2株遗传稳定性较好的突变菌株ANU1及ANU4,其中ANU4产量最高达1.92 g/L,比出发菌提高了8.7倍。     

应用基因组改组选育耐糖L-乳酸高产菌株

本研究应用基因组改组提高鼠李糖乳杆菌的耐糖能力,进而提高L-乳酸的产量。通过紫外线和亚硝基胍诱变方法获得8株改良出发菌株。考察了氨基酸前处理和变溶菌素对原生质体形成的影响。利用双亲灭活的原生质体进行递进式融合,经过两轮基因组改组和碳酸钙高糖平板及瓶筛选,选育出了耐糖改组菌株F2-2。在初糖浓度为150g/L发酵罐中,F2-2的乳酸产量为140g/L,是野生型乳杆菌的1.8倍。结果表明基因组改组技术能够快速提高乳酸菌耐糖和产酸能力两个表型。     

L-精氨酸生产菌的诱变育种研究

实验采用亚硝基胍对谷氨酸棒杆菌(Coynebacterumglutamicum)进行诱变处理,以添加了L-精氨酸结构类似物磺胺胍的筛选平板,筛选黄胺胍抗性突变菌株,将突变菌株进行摇瓶发酵实验,选育出1株L-精氨酸产量较高和产酸性能比较稳定的突变菌株,该菌株L-精氨酸产量比出发菌株提高了56.7%。     

常温常压等离子体诱变选育高产L-异亮氨酸谷氨酸棒杆菌

以谷氨酸棒杆菌（Corynebacterium glutamicum）23798为原始菌株,对其进行常温常压等离子体（ARTP）诱变,以磺胺胍抗性和氨基酸与茚三酮特异显色为筛选标记,以期得到高产L-异亮氨酸的诱变谷氨酸棒杆菌,并对其遗传稳定性进行研究。结果表明,原始菌株23798经过ARTP诱变处理180 s后,经0.4 mg/mL磺胺胍抗性筛选、多孔板高通量筛选、发酵培养复筛,选育出一株高产L-异亮氨酸诱变谷氨酸棒杆菌（Corynebacterium glutamicum）B1。该菌株在摇瓶中发酵培养48 h,L-异亮氨酸产量达18.5 g/L,比原始菌株提高62.03%,且遗传性状稳定。     

基因改组选育高产杆菌肽地衣芽孢杆菌及改组菌株差异分析

为了提高地衣芽孢杆菌肽产量,采用全基因组改组技术进行菌株选育。以地衣芽孢杆菌TJ12为原始菌株,通过紫外诱变、亚硝基胍诱变、常压室温等离子体诱变构建了TJ12菌的突变体库。在优化其原生质体制备和再生条件的基础上,以其中4 株诱变菌株（U11、U23、H1、L71）作为亲本,采用聚乙二醇介导的方法进行3 轮多亲本的全基因组改组,同时,结合双亲灭活的筛选方法,最终选出1 株杆菌肽产量提高并能稳定遗传的优良菌株F3,对其摇瓶发酵36 h,杆菌肽A产量达760 mg/L,为野生菌株TJ12的1.7 倍。与野生菌株TJ12相比,改组菌株提前进入生长稳定期,两者发酵过程pH值几乎无差异;最终改组菌生长量虽低于野生菌,但菌株单位细胞还原糖产量及杆菌肽产量都高于野生菌株;其合成基因和调控基因表达量相对野生菌株都上调,其中合成基因上调幅度较大。推测改组菌株自身有了更强大的杆菌肽耐受机制,且合成基因相关部位可能发生了改变。     

基因组改组选育氨肽酶和自溶度高的植物乳杆菌

利用基因组改组方法筛选出促进干酪成熟的非发酵剂乳酸菌。采用紫外线和亚硝基胍两种传统的诱变方法对植物乳杆菌进行诱变,通过检测自溶度、氨肽酶、产酸能力指标获得6株氨肽酶活性和自溶度均有所提高的突变菌株。以获得的突变菌株为出发菌株,应用灭火双亲原生质体融合后致死损伤得到的互补获得活性融合子的方法,对其进行基因组改组,经自溶度、氨肽酶、产酸能力筛选,获得1株遗传性能稳定的菌株,其氨肽酶活力为34.01个酶活单位,比出发菌株提高了3.09倍,自溶度为56.45%,比出发菌株提高了3.16倍。     

采用全基因组改组技术选育蛋白酶高产菌株

为了提高枯草芽孢杆菌B4的蛋白酶产量,采用全基因组改组技术进行菌株选育,先通过紫外诱变构建了B4菌的突变体库,在优化其原生质体制备和再生条件的基础上,以其中4株诱变菌株(BRS1、BRS2、BRS5、BRS6)作为亲本,采用PEG介导的方法进行两次多亲本的全基因组改组,同时,结合双亲灭活的筛选方法,共筛选出3株酶活力大幅度提高并能稳定遗传的优良菌株,为BRS1、BRS5、BRS6,酶活力最高达2175.81U/mL,达到原始菌株的3.01倍。     

ldhA基因敲除对Corynebacterium glutamicum TCCC11822发酵生产L-谷氨酸的影响

针对L-谷氨酸发酵过程中乳酸产量偏高的问题,以L-谷氨酸生产菌谷氨酸棒杆菌(Corynebacterium glutamicum)TCCC11822为出发菌株,通过构建敲除质粒pK18mobsacB△ldh并采用同源重组技术敲除其乳酸脱氢酶编码基因ldhA,以期达到减少副产物、提高L-谷氨酸产量和转化率的目的。结果表明,与出发菌株相比ldhA基因敲除株的乳酸合成量降低了85.6%,L-谷氨酸的产量和转化率分别提高7.6%和5.5%,但生物量略有下降。本研究可为L-谷氨酸及其他氨基酸生产菌株的理性改造提供参考。     

1dhA基因敲除对Corynebacterium glutamicum TCCC11822 发酵生产L-谷氨酸的影响

针对L-谷氨酸发酵过程中乳酸产量偏高的问题,以L-谷氨酸生产菌谷氨酸棒杆菌（Corynebactenum glutamicum） TCCC 11822为出发菌株,通过构建敲除质粒pK18mobsacB△1dh并采用同源重组技术敲除其乳酸脱氢酶编码基因1dhA,以期达到减少副产物、提高L-谷氨酸产量和转化率的目的.结果表明,与出发菌株相比1dhA基因敲除株的乳酸合成量降低了85.6％,L-谷氨酸的产量和转化率分别提高7.6％和5.5％,但生物量略有下降.本研究可为L-谷氨酸及其他氨基酸生产菌株的理性改造提供参考.     

利用全基因组改组技术提高SubtilosinA的产量

以Bacillus subtilis nja A1B2-2为出发菌株,在最佳的原生质体形成、再生和融合条件的基础上,将前期经过理化诱变筛选的四株高产菌株进行两轮基因组改组。结果表明,当以0.6mol/L Na Cl为高渗洗涤液,0.1mg/m L溶菌酶酶解40min后,涂布在以SMM为高渗体系的NB再生培养基上,原生质体形成率达到95.49%,再生率为89.25%。优化原生质体的融合条件,融合率达到了1.39×10-3。在此基础上将四株高产Subtilosin A菌株进行两轮全基因组改组,结合双亲灭活的筛选方法,挑选出一株遗传性状稳定的高产菌株R2-264,产量达17.59mg/L,比出发菌株提高了3.58倍。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press