PTT纤维的发展和应用

综述了新型纺织材料———聚对苯二甲酸丙二醇酯(PTT)的聚合、性质、纺丝工艺及其应用。并分析了PTT的研究和发展前景。     

PTT纤维

PTT即聚对苯二甲酸丙二醇酯是1，3-丙二醇(PDO)和对苯二甲酸（TPA)缩聚制成的芳香族聚合物。它的分子结构为：     

budR表达水平对克雷伯氏菌甘油代谢的影响

通过过量表达和反义RNA抑制改变budR表达水平,考察budR表达水平对克雷伯氏菌甘油代谢的影响。过表达budR使得Bud B和Bud C的酶活提高了48.7%和69.7%,1,3-丙二醇产量降低了12.6%,2,3-丁二醇含量增加了73.3%,同时乙酸含量显著降低。反义RNA抑制budR表达后,Bud B和Bud C酶活分别降低了56%和78%,重组菌的生物量、2,3-丁二醇(BDO)、乙酸、乳酸等均表现为略有降低,1,3-丙二醇含量达到23.4g/L,提高约10%。上述结果进一步丰富了budR基因在调控bud操纵子的表达水平、2,3-丁二醇合成及克雷伯氏菌甘油代谢中的作用,为后续代谢改造克雷伯氏菌合成1,3-丙二醇提供了新的思路。     

发酵后期补加2种氮源对克雷伯氏菌合成1,3-丙二醇的影响

为探寻解决重要平台化合物1,3-丙二醇发酵后期菌体生长和1,3-丙二醇合成受限的方法,通过从菌体量、产物和关键酶活性及基因转录水平等方面,较全面地考察了发酵后期补加酵母膏和硫酸铵对克雷伯氏菌(Klebsiella pneumoniae)合成1,3-丙二醇的影响,结果为:添加两种氮源均有利于菌体生长;补加10 g/L酵母膏和硫酸铵,1,3-丙二醇产量由58.6 g/L分别提高到70.6 g/L和77.2 g/L;相对于酵母膏,硫酸铵对关键酶活性的增强更为明显,并使甘油脱氢酶(glycerol dehydrogenase,Dha D)在发酵后期始终维持较高水平,促进细胞生长和产物合成。此外,与补加酵母膏相比,补加硫酸铵后关键酶基因转录水平上调并不显著。表明硫酸铵主要通过直接激活关键酶活性促进细胞生长和产物合成。综上所述,发酵后期补加硫酸铵更利于1,3-丙二醇的生物合成,是提高发酵合成1,3-丙二醇水平的有效方式之一。     

PET、PTT与PBT材料的定性与定量鉴别方法

传统的纤维成分定量分析测试方法如AATCC 20A—2010虽然可以区分芳香族聚酯和其他纤维材料,但无法鉴别聚酯种类。为此,利用PET,PTT和PBT熔点的不同,采用差示扫描量热法来定性区分不同的聚酯成分,并利用不同基团化学位移的差异,采用核磁共振法进一步定量鉴别聚酯的含量。结果表明:差示扫描量热法结合核磁共振法可以有效准确地鉴别芳香族聚酯的类型和含量,可重复性好,可以推广应用于纺织制品的检测,也可应用于聚酯类工程塑料等领域的成分分析鉴别。     

PTT纤维的基本力学性能研究

主要介绍了PTT纤维的截面形态,对PTT纤维的力学性能和在不同夹持方式下力学性能的变化进行了研究,与PET纤维进行力学性能比较,经过实验分析得到,湿态下PTT纤维和干态PTT纤维的初始模量、断裂强度几乎无变化,而湿态的PTT纤维伸长率比干态时高。干态时PTT纤维的初始模量、断裂强度均低于干态PET纤维;PTT纤维在结节状态下断裂强度和断裂伸长率小于在勾结状态下的断裂强度和断裂伸长率。     

PTT纤维记忆面料的染整工艺

介绍了PTT纤维记忆面料的精练、染色和后整理工艺.试验认为,精练时要加入低聚物防止剂;采用安诺可隆PTT系列分散染料染色时,染色温度宜控制为110℃,染色时间应不低于90 min;后整理工艺条件以130℃定形60 s为佳.     

热定形对PTT纤维结构和可染性的影响

用傅立叶红外光谱和临界溶解时间法研究了热定形对PTT纤维结构的影响,讨论了热定形温度和时间对PTT纤维可染性的影响.热定形增加了PTT纤维结晶程度,PTT纤维的可染性随着热定形温度的升高先降低后增加,170℃定形试样的可染性最低;分子量大的偶氮分散染料对热定形引起的PTT纤维微细结构差别的敏感性大.     

用克雷伯氏菌批式流加发酵法生产1,3-丙二醇

通过对克雷伯氏菌在 7L发酵罐中厌氧间歇发酵甘油生产 1,3 丙二醇的实验研究 ,建立了一种与 pH调节相偶联的批式流加甘油发酵策略。考察了不同甘油维持浓度条件下的流加方式及不同培养方式对 1,3 丙二醇产率的影响。结果表明 ,甘油质量分数维持在 2 %的流加方式有利于 1,3 丙二醇的发酵生产 ,其在 30 5h内消耗甘油 2 80 g ,得到 1,3 丙二醇152 6 g ,摩尔转化率 6 5 5% ,生产强度 0 91g/L·h     

产1,3-丙二醇菌株的筛选、改良及发酵

从自然界筛选得到了9株可发酵甘油生产1,3 丙二醇的肠道细菌,经鉴定均为肺炎克雷伯氏菌.经化学诱变,菌株的1,3 丙二醇产量有所提高,其最终产量达到2%左右.     

Klebsiella pneumoniae在不同发酵罐中发酵甘油制1,3-丙二醇的控制条件研究

对克雷伯氏肺炎杆菌间歇发酵甘油产生1,3-丙二醇的发酵条件进行了优化,确定了50L搅拌式发酵罐和15L气升式发酵罐发酵的最佳发酵条件,得到的1,3-丙二醇的浓度、生产率和甘油摩尔转化率分别是80.97g/L、1.69 g/(h·L)、0.57 mol/mol和74.81 g/L、1.56 g/(h·L)、0.50 mol/mol;对比了不同类型发酵罐的发酵结果,表明50 L搅拌式发酵罐发酵结果优于15L气升式发酵罐,前者相对于后者来说,1,3-丙二醇的浓度和甘油摩尔转化率分别提高了8.23%和14.91%;确定了最适底物浓度(以初始甘油浓度计)在25 g/L左右。     

糖碳源和氨基酸氮源对苍白杆菌属发酵产生物表面活性剂的影响

该实验为优化苍白杆菌（Ochrobactrum sp.）产生物表面活性剂的发酵条件,比较了不同糖碳源（蔗糖、乳糖、甘油、木糖、果糖）、氨基酸氮源（谷氨酸、天冬氨酸、赖氨酸、精氨酸和缬氨酸）、碳氮比（C/N）（1、10、20、30、40）对生物表面活性剂发酵的影响。结果表明,最优碳源为蔗糖,发酵5 d达最大乳化活性56.30%;最优氮源为天冬氨酸,发酵4 d达最大乳化活性54.00%;最优C/N为10,发酵4 d达最大乳化活性55.75%。     

棘托竹荪菌丝体培养基碳源、氮源、无机盐的筛选

利用平板培养和试管斜面培养探讨影响棘托竹荪菌丝体培养的理化因子:碳源、氮源、无机盐。结果表明:棘托竹荪菌丝体在平板中和试管中对碳源、氮源、无机盐的利用情况是相似的;无论是平板中培养还是试管中培养,黄豆粉、硫酸铵、硝酸钾、Na+都能促进棘托竹荪菌丝体的生长,乳糖、蛋白胨、尿素都会阻碍菌丝体的生长。棘托竹荪对氮源的需求最高,其次是无机盐,而对碳源的需求不是很高。     

不同碳源对粘性红酵母WP3生长及类胡萝卜素产量的影响

研究了不同碳源及含量对粘性红酵母（Rhodotorula mucilaginosa）WP3生长及类胡萝卜素积累的影响。结果表明,在所研究的碳源中,葡萄糖有利于生长,而果糖有利于类胡萝卜素积累。在碳源含量为40 g/L,果糖和葡萄糖比例为7∶1,果糖含量为35 g/L,葡萄糖含量为5 g/L时,粘性红酵母WP3的生物量为7.94,类胡萝卜素产量达到556.84 μg/L,对粘性红酵母生长及类胡萝卜素合成有利。     

红光对安卡红曲霉GZU4577的调控及其与无机氮源的相关性

该研究基于无氮源察氏培养基,通过菌落观察、生长测量、分生孢子和闭囊壳计数及色价测定研究红光对安卡红曲霉（Monascus anka）GZU4577的调控及其与无机氮源的相关性。结果表明,在无氮源添加时,红光对菌株GZU4577的径向生长和各色素的色价无显著影响（P＞0.05）,但显著促进了分生孢子和闭囊壳的生成（P＜0.05）;添加无机氮源后,红光对菌株GZU4577的影响机制发生改变：添加硝酸钠（NaNO3）后,红光显著抑制菌株GZU4577的径向生长和分生孢子、闭囊壳的生成（P＜0.05）,但对各色素色价无显著影响（P＞0.05）。添加氯化铵（NH4Cl）后,红光只抑制菌株GZU4577的闭囊壳和各色素的生成（P＜0.05）。添加硝酸铵（NH4NO3）后,红光显著抑制了菌株GZU4577的闭囊壳和分生孢子、红色素和黄色素的生成（P＜0.05）。因此,红光对菌株GZU4577的调控与氮源存在与否及氮源种类相关。     

高果糖浆废液杂糖组分分析及其作为毕赤酵母发酵碳源的资源化利用

废杂糖的资源化利用是高果糖浆生产行业迫切需要解决的问题。该研究首先通过高效液相、质谱和红外光谱分析,确定了杂糖成分为葡萄糖、果糖和聚合度为2~16的线性葡聚糖,包括葡萄糖480 g/L,果糖92 g/L,麦芽糖103.6 g/L,麦芽三糖36.8 g/L,总糖含量802.3 g/L。进一步使用2种常用的毕赤酵母宿主(P AOX1型毕赤酵母、P GAP型毕赤酵母)利用杂糖发酵生产内切β-1,3葡聚糖酶并与标准碳源(甘油和葡萄糖)作对比。结果表明,对于P AOX1型毕赤酵母,杂糖做碳源时细胞密度和酶活性与甘油相比均有所下降,最大生物量分别为59.1和82.0 g/L,最高酶活性分别为157.29和199.2 U/mL。对于P GAP型毕赤酵母,杂糖与葡萄糖的发酵效果相当,说明杂糖可以作为P GAP型毕赤酵母生产内切β-1,3葡聚糖酶的优质替代性碳源。     

植物源食品中叶酸的生物合成与调控及其提取与检测技术研究进展

叶酸作为一碳代谢时的辅因子,是生物体的必需物质,对人体健康至关重要。本文综述了植物源食品中叶酸的类型与结构、叶酸合成途径及相关酶、叶酸代谢调控、发芽富集技术、叶酸提取与检测技术,并对开发快速而准确的叶酸测定方法、研发植物性食品中叶酸的富集与提取技术进行了展望。     

Influence of refrigeration and carbon dioxide addition to raw milk on microbial levels, free monosaccharides and myo-inositol content of raw and pasteurized milk

The influence of CO₂ treatment on free monosaccharides and myo-inositol in raw and pasteurized milk during cold storage was studied. Pasteurization did not cause significant changes in the monosaccharide fraction. No variations in the level of galactose and myo-inositol in untreated and CO₂-treated samples were observed during cold storage. The content of glucose decreased considerably during cold storage due to bacterial growth in pasteurized milk. During cold storage of pasteurized milk no changes in N-acetylgalactosamine were observed, whereas N-acetylglucosamine decreased considerably after 15 days. No differences between untreated and CO₂-treated milks were found. A substantial decrease in N-acetylglucosamine and a gradual increase in N-acetylgalactosamine were observed in raw milk during cold storage. The former was attributed to consumption of this hexosamine by microorganisms and the latter was probably due to microbial glycosidic enzymes. The addition of CO₂ to raw milk proved to be a useful treatment for milk preservation without modifying the free monosaccharide fraction. Received: 4 October 1999     

The influence of different nitrogen and carbon sources on mycotoxin production in Alternaria alternata

The aim of this study was to determine the influence of different carbon and nitrogen sources on the production of the mycotoxins alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) by Alternaria alternata at 28 °C using a semi-synthetic medium (modified Czapek-Dox broth) supplemented with nitrogen and carbon sources. Additionally the effect of shaken and static cultivation on mycotoxin production was tested. Initial experiments showed a clear dependency between nitrogen depletion and mycotoxin production. To assess whether nitrogen limitation in general or the type of nitrogen source triggers the production, various nitrogen sources including several ammonium/nitrate salts and amino acids were tested. In static culture the production of AOH/AME can be enhanced greatly with phenylalanine whereas some nitrogen sources seem to inhibit the AOH/AME production completely. TA was not significantly affected by the choice of nitrogen source. In shaken culture the overall production of all mycotoxins was lower compared to static cultivation. Furthermore tests with a wide variety of carbon sources including monosaccharides, disaccharides, complex saccharides such as starch as well as glycerol and acetate were performed. In shaken culture AOH was produced when glucose, fructose, sucrose, acetate or mixtures of glucose/sucrose and glucose/acetate were used as carbon sources. AME production was not detected. The use of sodium acetate resulted in the highest AOH production. In static culture AOH production was also stimulated by acetate and the amount is comparable to shaken conditions. Under static conditions production of AOH was lower except when cultivated with acetate. In static cultivation 9 of 14 tested carbon sources induced mycotoxin production compared to 4 in shaken culture. This is the first study which analyses the influence of carbon and nitrogen sources in a semi-synthetic medium and assesses the effects of culture conditions on mycotoxin production by A. alternata.