Rhodococcus sp.SHZ-1腈水合酶的高酶活发酵工艺

通过研究发酵过程中溶氧、生物量、腈水合酶活力以及残糖的变化规律和搅拌速度、通气量、接种量及诱导剂对产腈水合酶的影响,确立了5L发酵罐中Rhodococcus sp.SHZ-1腈水合酶的高酶活发酵工艺参数。结果表明,发酵过程中溶氧控制在30%以上有利于菌体快速生长和腈水合酶的合成。在pH7.2,温度30℃的发酵条件下,适宜的腈水合酶合成工艺条件为:接种量10%,通气量1.0vvm,搅拌速度采用由初始的200r/min调至500r/min的变速调控方式,同时于48h补加产酶诱导剂,发酵液腈水合酶的最高酶活力达到了9500U/mL,是摇瓶培养时最高酶活力8208U/mL的1.2倍,且比未进行工艺优化时最大产酶期缩短了20～24h,其最佳产酶期为52～60h。     

α-半乳糖苷酶的液体发酵条件和酶学性质研究

研究了臭曲霉ZU-G1液体发酵产α-半乳糖苷酶的最佳生产条件及其酶学性质.试验结果表明,最适发酵条件为温度28℃.转速200 r/min,装液量30 mL(250 mL三角瓶),接种量6.6%,种子培养18 h后接种,发酵144 h后α-乳糖苷酶酶活达到最大值.在此发酵条件下α-半乳糖苷酶最适pH 5.0,于28℃放王7 h,在pH 3.5～6.0内稳定性较好;该酶的最适温度为60℃,在50℃以下存放稳定性较好.Ag 可强烈抑制该酶的活性,Ca2 、Mg2 、Mn2 和Zn2 的激活效果随浓度而变.1mmol/L甘露醇、抗坏血酸和2mmol/L蜜二糖对酶的热稳定性保护效果好.     

恶臭假单胞菌产精氨酸脱亚胺酶发酵条件及特性的研究

对恶臭假单胞菌N0705产精氨酸脱亚胺酶的发酵条件及部分酶学性质进行了研究.结果表明,在培养温度28℃,培养基初始pH值为6.6,接种量4%,装液量40mL/250mL,发酵时间50h时,精氨酸脱亚胺酶酶活最大.精氨酸脱亚胺酶发酵粗酶液在温度37℃及pH 6.0～7.0时有较好的稳定性.     

双酶协同法糖化玉米及L-乳酸发酵工艺的研究

通过均匀试验对双酶协同作用进行了玉米糖化条件、发酵条件的研究,得出最佳糖化条件为：糖化温度64℃、α-淀粉酶添加量0.0435g/20g玉米粉、糖化酶添加量0.0742g/20 g玉米粉、pH 5.7、糖化时间6h,还原糖含量可达119.96g/L;最佳发酵条件为：发酵温度37℃、接种量10%、发酵时间48 h,添加麸皮量为30g/100g玉米粉,乳酸得率136.92g/L.     

高产蛋白酶菌株的筛选及产酶条件优化

从山西临汾汾河滩涂的表层土壤中分离到22株产蛋白酶菌株,用检测蛋白酶产生水解圈和蛋白酶活性测定相结合的方法,从中筛选出一株高产蛋白酶菌株P5,并通过正交试验对其产酶条件进行了研究。结果表明,影响P5菌株发酵产酶因素的主次顺序为培养温度、接种量、培养时间;影响P5菌株发酵培养基组成因素的主次顺序为氮源含量、起始pH值、碳源含量;确定的P5菌株的最佳产酶条件为,在以30 g/L葡萄糖为碳源,50 g/L蛋白胨为氮源,起始pH7.0的最适产酶培养基中,培养温度35℃,接种量为8%的条件下发酵培养48 h,具有最大产酶量,其蛋白酶活力可达129.2 U/mL。     

一株里氏木霉产纤维素酶发酵条件的研究

对里氏木霉产纤维素酶的发酵条件进行研究,结果表明:产酶最佳碳源为2‰麸皮、最佳氮源为(NH4)2SO4、培养时间96～120h、发酵瓶装液量60ml、培养温度25～30℃、培养液初始pH4.5～5.0。     

S.griseoverticillatum合成谷氨酰胺转胺酶发酵条件的研究

本文以S.griseoverticillatu ZY13作为生产菌株,利用液体深层发酵技术生产谷氨酰胺转胺酶.结果表明在500 mL摇瓶中,菌株ZY13的最佳种龄48 h、最佳培养温度28～30℃、培养时间64 h、pH值6.5～7.0、接种量5%～10%、装液量100 mL.培养基最佳组合为淀粉30 g/L、蛋白胨35 g/L和酵母膏3 g/L.添加硝酸钠有利于MTG的积累,酶活比对照提高了31%.在7.0 L台式发酵罐中发酵,适宜的初始pH值7.0,温度30℃,通气量2.0 L/min,搅拌转速150 r/min.MTG分批发酵与摇瓶相比较,发酵周期缩短了8小时,菌体细胞干重、酶活和生产强度分别增加了16%、27%和46%.     

紫外- 氯化锂复合诱变选育中性植酸酶高产菌株

以放射型根瘤杆菌为出发菌株,对其进行紫外-氯化锂(LiCl)复合诱变筛选,得到一株产中性植酸酶酶活力较高的菌株。当培养温度为30℃、pH值为7.0、接种量为10%时,经96h培养后,该菌株产中性植酸酶活力最高达到18.49U/mL,比原始菌株提高47.68%,且发酵周期缩短12h,该菌株具有良好的遗传稳定性。     

黑曲霉产糖化酶液态发酵条件研究

以糖化酶活力为指标,通过单因素实验,分别考察了添加物、补料时间和补料量对黑曲霉发酵产糖化酶的影响。通过正交实验,考察了发酵条件对黑曲霉发酵产酶的影响。结果表明,添加0.4%的(NH4)2SO4作为促进剂可使酶活提高17%,最佳补料时间为48 h,补料量6 mL,补料可使发酵周期由原来的96 h延长到120 h;最佳发酵条件为接种量15%,250 mL三角瓶装液量50 mL,初始pH为4.5。     

乳中蛋白肽提取工艺研究

以脱脂乳粉为原料.从国家卫生部公布的益生菌株中筛选出干酪乳杆菌干酪亚种为最佳理想的生产菌株,采用微生物发酵法将乳蛋白转化为小分子的乳蛋白肽,确定菌种培养以及发酵的最佳工艺参数,即培养基浓度10%、培养温度35℃、培养时间36 h、pH自然时酶的活性最强.发酵是在pH自然状态下、发酵温度35℃、接种量在7%、发酵时间72 h,此时蛋白质的利用率在96%以上,肽比率达80%以上.为最佳的工艺参数.     

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