HPLC法测定木糖母液中的糖组分

目的:建立高效液相色谱法测定木糖母液中糖组分的方法。方法:采用AminexHPX-87H柱(7.8mm×300mm),以0.005mol/L硫酸为流动相,流速为0.5mL/min,柱温50℃,检测器为示差检测器,进样量20μL。结果:以峰面积定量,葡萄糖的线性范围为5~50μg(r=0.9999),平均回收率99.8%,RSD=0.80%(n=9);木糖的线性范围为10~100μg(r=0.9999),平均回收率100.2%,RSD=0.52%(n=9);阿拉伯糖的线性范围为5~50μg(r=0.9997),平均回收率99.6%,RSD=0.75%(n=9)。结论:该方法简便、结果准确可靠,可用于木糖母液中糖组分的测定。     

木糖母液生产饲料酵母的研究

本研究利用木糖生产过程中的木糖母液为主要原料生产饲料酵母。其得率为３６．３２％，蛋白质含量达５２．５４％，优于轻工业部饲料酵母的质量标准。为木糖母液的利用提出了切实可行的发展方向。     

木糖母液生产饲料酵母的研究

本研究利用木糖生产过程中的木糖母液为主要原料生产饲料酵母。其得率为３６．３２％，蛋白质含量达５２．５４％，优于轻工业部饲料酵母的质量标准。为木糖母液的利用提出了切实可行的发展方向。     

木糖醇母液色谱分离性能优化

在实验室模拟移动床(SMB)分离设备上成功地实现了木糖醇母液中木糖和木糖醇组份的分离提纯。并在平衡理论的框架下,采用基于真实移动床(TMB)的简化数学模型,以产品纯度和收率为系统分离性能的优化指标,研究SMB分离性能与操作条件之间的关系。通过对木糖醇母液SMB色谱分离过程操作条件的寻优仿真研究,确定稳态时柱内的木糖和木糖醇浓度分布状态;计算出不同操作条件时两组分产品液各自的纯度和收率变化规律图。在阀门切换时间为15min,进料木糖醇母液中木糖浓度35gL-1,木糖醇浓度114gL-1,进料和出料总量恒定为16mLmin-1,循环洗脱剂流量恒定为18mLmin-1的操作条件下,木糖醇母液进料流量在1~2.3mLmin-1范围内都可同时获得纯净木糖醇与木糖产品。在实验室SMB分离设备上进行了验证,得到的木糖和木糖醇产品液纯度和收率均达到了100%,所有实验结果与仿真曲线基本吻合。因此采用基于TMB的简化的平衡理论模型进行仿真和优化研究可分析和预测木糖母液SMB色谱分离系统操作条件对系统分离性能的影响,有效地指导了产品分离实验、工业化放大设计和生产优化操作。     

木糖与木糖醇色谱分离操作的质量优化

利用模拟移动床（SMB）连续色谱技术分离木糖醇母液中的木糖和木糖醇组分。在平衡理论的框架下，提出了使用基于相应的真实移动床（TMB）的简化数学模型，来研究各进料液和产品流出液的流量等操作参数的变化，对SMB分离性能（以纯度和收率作为性能指标）影响的方法。采用本方法进行了操作条件寻优仿真，并取得满意结果。在实验室SMB分离设备上，基于此最佳操作条件所得到的木糖和木糖醇产品液纯度和收率均达到100％。     

响应面优化木糖母液发酵产丁二酸

对产琥珀酸放线杆菌（Actinobacillus succinogenes）GXAS137发酵木糖母液产丁二酸的条件进行优化,探索利用废弃木糖母液合成高附加值丁二酸的可行性。首先通过Plackett-Burman实验设计确定影响丁二酸发酵的显著因子,然后采用最陡爬坡实验逼近各显著因子的最优区域,最后通过Box-Behnken实验设计确定各因子的最优水平。影响木糖母液发酵产丁二酸的显著因子及最优浓度分别为：木糖母液64.75g/L,玉米浆15.71g/L,碱式碳酸镁46.39g/L。在最优发酵培养条件下,丁二酸产量达到38.01g/L,比优化前提高了20.7%,与模型预测值（38.41g/L）基本一致。进一步利用2L发酵罐进行了放大试验,发酵72h丁二酸产量最高可达48.99g/L,较厌氧瓶发酵提高了28.9%,丁二酸得率为0.80g/g总糖。结果表明,采用低价的木糖母液作为底物,可为未来低成本、高效产业化生产丁二酸奠定坚实的基础。     

固定床色谱分离木糖、山梨糖的实验研究

一、前言 由玉米芯(或甘蔗渣)水解法生产木糖的工艺中,水解液中的木糖由结晶的方法得到。木糖结晶母液中,除了未结晶出来的木糖之外,还含有大量山梨糖以及少量其他糖类,用结晶的方法已难以进行深度分离,由于木糖、山梨糖都是高价值产品,因此开发木糖结晶母液的深度分离技术具有很大的经济价值。     

混合醇回收结晶母液中活性成分林可霉素的研究

盐酸林可霉素丙酮结晶工艺生产收率在90％左右，约有10％林可霉素留存在丙酮母液中，探讨了利用混合醇回收丙酮母液中林可霉素的可行性，经实验选用了合理的回收工艺，应用于生产后，产品质量稳定，提高了林可霉素提炼收率约5％。     

HPLC-ELSD法测定低聚木糖中的木糖和木二糖

建立了高效液相色谱-蒸发光散射检测器(HPLC-ELSD)测定低聚木糖中的木糖和木二糖含量的方法。以Prevail TM Carbohydrate ES糖柱(250×4.6,5μm)为色谱柱,乙腈—水(72∶28,V/V)为流动相,流速为1.0 m L/min,柱温为25℃,进样量为10μL,ELSD漂移管温度为80℃,载气流速为2.0 L/min。结果表明,木糖和木二糖分别在0.08~1.00 mg/m L和0.15~2.00 mg/m L质量浓度范围内线性关系良好,检出限分别为0.01mg/m L和0.02 mg/m L,定量限分别为0.03 mg/m L和0.05 mg/m L,样品加标回收率为97%~102%。     

醇解母液生产醋酐工艺的探讨

以醋酸甲酯和一氧化碳为原料,采用羰基化生产醋酐是一项解决电石法生产聚乙烯醇（PVA）副产物醋酸甲酯和电石炉气一氧化碳较为可行的方法,对羰基化生产醋酐的原理和醇解母液生产醋酐的工艺过程进行了介绍,并对存在的问题进行了讨论。     

新型合金催化剂用于木糖加氢制木糖醇的正交试验研究

采用RTH 311催化剂进行木糖加氢,考察了温度、压力、pH值、剂糖比和反应时间等因素对木糖加氢反应的影响,并采用正交试验方法得出木糖转化率达到最大时的工艺参数。结果表明,当pH值为65、反应温度140 ℃、反应压力10 MPa、反应时间为110 min、剂糖质量比为25%时,木糖转化率高达99.99%。     

Profiles of xylose reductase,xylitol dehydrogenase and xylitol production under different oxygen transfer volumetric coefficient values

BACKGROUND: Xylitol is a sugar alcohol (polyalcohol) with many interesting properties for pharmaceutical and food products. It is currently produced by a chemical process, which has some disadvantages such as high energy requirement. Therefore microbiological production of xylitol has been studied as an alternative, but its viability is dependent on optimisation of the fermentation variables. Among these, aeration is fundamental, because xylitol is produced only under adequate oxygen availability. In most experiments with xylitol‐producing yeasts, low oxygen transfer volumetric coefficient (K_La) values are used to maintain microaerobic conditions. However, in the present study the use of relatively high K_La values resulted in high xylitol production. The effect of aeration was also evaluated via the profiles of xylose reductase (XR) and xylitol dehydrogenase (XD) activities during the experiments. RESULTS: The highest XR specific activity (1.45 ± 0.21 U mg_protein^?1) was achieved during the experiment with the lowest K_La value (12 h^?1), while the highest XD specific activity (0.19 ± 0.03 U mg_protein^?1) was observed with a K_La value of 25 h^?1. Xylitol production was enhanced when K_La was increased from 12 to 50 h^?1, which resulted in the best condition observed, corresponding to a xylitol volumetric productivity of 1.50 ± 0.08 g_xylitol L^?1 h^?1 and an efficiency of 71 ± 6.0%. CONCLUSION: The results showed that the enzyme activities during xylitol bioproduction depend greatly on the initial K_La value (oxygen availability). This finding supplies important information for further studies in molecular biology and genetic engineering aimed at improving xylitol bioproduction. Copyright © 2008 Society of Chemical Industry     

高浓度糖醇制药废水的处理

介绍了"曝气调节 微电解反应 中和沉淀 UASB厌氧 好氧ICEAS"为主体的工艺在高浓度糖醇制药废水治理中的应用情况.监测数据表明,该工艺处理效果稳定、可靠,出水指标能够达到GB 8978-1996污水综合排放标准中二级标准.产生了有良好的社会效益和经济效益.     

新型合金催化剂用于木糖加氢制木糖醇的研究

采用三元Raney Ni合金催化剂进行木糖加氢，考察了温度、压力、pH值、剂糖比和反应时间等因素对加氢反应的影响，并与其它Raney Ni类催化剂进行了对比。结果表明，使用Raney Ni催化剂RTH-311进行木糖加氢，当反应温度为130-140℃、压力为8-10MPa、pH值为6-7、剂糖质量比为2％、反应时间为90～120min时，转化率可达100％，产品色度好。RTH-311催化剂的木糖加氢活性好于其它类催化剂，重复使用时，也可保持较高活性。     

Effect of glucose:xylose ratio on xylose reductase and xylitol dehydrogenase activities from Candida guilliermondii in sugarcane bagasse hydrolysate

The influence of glucose on xylose reductase (XR) and xylitol dehydrogenase (XDH) enzyme activity was evaluated from sugarcane bagasse hydrolysate fermentations with different glucose:xylose ratios (1:25, 1:12, 1:5 and 1:2.5) by employing an inoculum of Candida guilliermondii grown in media containing glucose, a mixture of glucose and xylose, or only xylose as carbon sources. According to the results, the glucose:xylose ratio affected positively this bioconversion and a correlation was not observed between the favourable conditions for xylitol production and the XR and XDH activities. Also, the results were influenced not only by the glucose:xylose ratio in the fermentation medium, but also by the carbon source employed in the growth medium of the inoculum. The optimum condition for xylitol production by C. guilliermondii in sugarcane bagasse hemicellulosic hydrolysate should use hydrolysate with a 1:5 glucose:xylose ratio and inoculum grown in medium containing xylose as the only carbon source. Copyright © 2006 Society of Chemical Industry     

Use of response surface methodology to evaluate the optimum environmental conditions for the bioconversion of xylose into xylitol in eucalyptus hemicellulosic hydrolysate

Candida guilliermondii fermented a eucalyptus hemicellulosic hydrolysate that had been treated with calcium oxide, phosphoric acid and activated charcoal. The influences of different xylose and ammonium sulfate concentrations on the production of xylitol were studied. A response surface was obtained with value R² > 0.97 and p < 0.01. The model estimated a maximum xylitol production of 20.82 g dm^?3 in the culture medium supplemented with ammonium sulfate (1.8 g dm^?3) and xylose (45.5 g dm^?3). Copyright © 2003 Society of Chemical Industry     

Induction of xylose reductase and xylitol dehydrogenase activities on mixed sugars in Candida guilliermondii

The ability of various sugars to induce xylose reductase (aldose reductase, EC 1.1.1.21) and xylitol dehydrogenase (D -xylulose reductase, EC 1.1.1.9) activities in Candida guilliermondii was studied. D -Xylose was found to be the best inducer of activities of both enzymes, followed closely by L -arabinose. Very low xylose reductase activity was induced by cellobiose, D -mannose, D -glucose, D -galactose, D -fructose or glycerol. With xylitol dehydrogenase, cellobiose and D -fructose caused partial induction of enzyme activity, while negligible activity was induced by D -mannose, D -glucose, D -galactose or glycerol. Several sugars were tested for the ability to repress the induction by D -xylose of xylose reductase and xylitol dehydrogenase activities in C. guilliermondii. Enzyme activities induced on D -xylose served as controls. L -Arabinose, cellobiose and D -galactose did not repress enzyme induction by D -xylose, while D -mannose, D -glucose and D -fructose repressed enzyme induction to varying extents. Results from enzyme induction generally correlated with patterns of mixed sugar utilization, with some anomalies associated with the utilization of D -galactose and D -fructose in the presence of D -xylose. The results show that the utilization of D -xylose by C. guilliermondii is subject to regulation by induction and catabolite repression.     

木糖废液制取酱色素方法及其产品的稳定性研究

以木糖生产中的废液制取食用酱色素 ,研究了各种因素对酱色素稳定性的影响。结果表明 ,一般热、光、溶液pH值对其的影响不大 ;在一般浓度下 ,Ca2 ,Na ,K ,Al3 ,Fe3 ,蔗糖 ,苯甲酸钠 ,食盐等物质对其基本无影响 ;当Mg2 ,Zn2 ,Fe3 ,抗坏血酸的含量高时对其有不利影响。