木聚糖溶液超滤透过率的研究

研究了玉米芯碱抽提所得木聚糖溶液不同的超滤膜超滤时溶剂透过率与主要操作参数间的关系。研究发现,增加操作压力,通过PLGC、PLCC两种超滤膜的溶剂透过率随之增加,但对PLCC超滤膜而言,适宜的操作压力不应超过80kPa;进料速度对PLGC超滤膜的溶剂透过率影响较大,J∝u∧0.63b,而对PLCC超滤膜的溶剂透过率影响较小,J∝u0.09b,料液浓度与溶剂透过率间关系符合膜模型,膜面上溶质浓度与膜截留分子量和操作条件有关。用均匀设计考察操作参数对透过率的影响,结果表明,对截留分子量大的超滤膜（PLGC）而言,进料速度是控制溶剂透过率的最关键因素,而对截留分子量小的超滤膜（PLCC）,操作压力是控制溶剂透过度的最关键因素。同时,对各操作参数与溶剂透过率间的关系进行了关联,各模型预测值与实验值吻合较好,相对误差小于7%。     

膜反应器中木聚糖的酶水解反应

以木聚糖为底物、木聚糖酶为催化剂，在木聚糖质量浓度为30．0g/L，操作压力16kPa，进料速度400mL/min，时间12h,pH值5．0，温度为48摄氏度的条件下研究了超滤膜反应器中木聚糖的酶水解反应。结果表明，木聚糖的酶水解总糖得率为60．10％，未水解木聚糖聚合度为10左右，碱溶对聚合度没有影响，未水解木聚糖重新水解，总糖得率为7．50％。     

膜分离技术精制塔拉单宁酸的研究

通过对超滤膜截留相对分子质量、操作压力、料液浓度的研究，确定截留相对分子质量为4000的膜、0．7MPa的操作压力、45g／L的料液浓度为最佳超滤条件，透过液的单宁酸含量达到93．6％；纳滤试验表明，截留相对分子质量为400的膜，其截留液的单宁酸含量达到95．9％，好于截留相对分子质量为600以及800的膜。     

大孔树脂吸附及超滤膜技术提纯蓝莓花色苷中试研究

比较了4种大孔吸附树脂的吸附和解析能力，确定生产最适合的树脂；分析了温度、pH值、洗脱剂浓度对树脂吸附的影响，确定最有利于产业化的工艺参数；通过不同压力、截留分子量比较超滤结果，选择最优化的超滤工艺参数。试验结果表明：在4种树脂中，D101树脂具有最佳的吸附性能；采用D101大孔树脂和6000道尔顿分子量的超滤膜纯化技术对野生蓝莓花青素纯化效果最佳，花青素纯度可达35％以上。     

麦草亚铵法黑液的超滤研究

研究了超滤技术处理麦草蒽醌-亚硫酸铵(麦草亚铵)法黑液的规律,探讨了超滤膜的选择、温度、压力等操作参数对超滤过程的影响.研究表明:截留分子质量为10ku的聚醚砜(PES)超滤膜较适合于分离此黑液,并具有较好的抗污染性;在操作压力0.20MPa、温度25℃下进行超滤,随着体积减少量( V R)的增加,灰分的透过率增加,截留液被浓缩.对超滤处理前后的黑液进行物化性能的对比研究表明:超滤后截留液中的木质素高相对分子质量( M r)部分比例增加;截留液中的磺酸基、羧基和酚羟基的含量均比黑液中的高;组成与结构上的变化对物化性能的影响表现在:净浆流动度提高了45.7%,即通过超滤能增强黑液的应用性能.     

落叶松栲胶超滤时截留规律的研究

研究落叶松栲胶超滤过程中，操作压力、原料液浓度、搅拌速率等因素对截留率的影响，利用浓度差极化模型求得膜面上溶质浓度，以便计算相应的真实截留率。结果表明：对浓度及压力而言，起初截留率与表观截留率变化规律相似，而且前才总是大于后者。     

松树皮原花青素的超声提取、超滤膜分离中试研究

通过松树皮原花青素的超声提取、膜分离纯化技术中试试验,考察了超声波提取温度、料液比、提取时间等单因素对原花青素得率的影响,试验得到了超滤膜工作压力、截留分子量的最佳工艺参数。结果表明,采用超声波强化逆流提取松树皮原花青素的最佳参数为：料液比1：12,超声温度60℃,提取时间30min;超滤膜分离纯化工艺参数为：膜工作压力0．2MPa,截留分子量5000。试验获得的松树皮原花青素经检测含量可达95％以上。     

膜分离制备红松松塔多糖的研究

对红松松塔多糖的膜分离制备工艺进行研究。采用微滤、超滤联用的方法制备红松松塔多糖,考察了微滤过程中料液温度、操作压力和料液浓度对膜通量的影响,并通过正交实验确定了最佳微滤条件;利用超滤对红松松塔多糖料液进行纯化,并用截留分子量100kDa、50kDa、10kDa、6kDa的超滤膜对红松松塔多糖进行了分级分离。结果表明,微滤最佳条件为料液浓度25g/L、压力0.10MPa、温度40℃;超滤纯化后多糖含量由7.20%提高到35.16%。得出红松松塔多糖分子量分布结果如下:分子量>10万的占9.50%,5万~10万之间的占70.20%,1万~5万之间的占3.20%,6000~1万之间的占17.1%。结论,应用膜分离制备红松松塔多糖可行,且能较好地分离纯化红松松塔多糖。     

从稻壳中提取木聚糖的研究

以稻壳为原料，采用制备综纤维素再碱提取的方法，分析了不同碱溶液浓度、温度、固液比和时间对稻壳半纤维素中多戊糖得率的影响。实验结果表明，稻壳中多戊糖含量为19.9％，是较好的木聚糖资源。碱提取稻壳中木聚糖的方法为：预处理：80℃水浸泡3h：碱提取条件：碱质量分数10％，固液比（g：mL）1：10，提取时间3h，提取温度80℃。木聚糖提取率达原料中木聚糖总量的67．50％以上。     

纳米木聚糖处理对木材防腐性能的影响

以玉米芯为原料,利用正交试验优化提取温度、碱浓度、固液比等制备木聚糖的工艺参数。以制备的木聚糖为研究对象,通过改进工艺,制备粒径较小、分子量较低的纳米木聚糖,并以其为防腐剂处理杨木试样,结果表明:木聚糖提取率影响因素的顺序为:提取温度碱浓度固液比,理想工艺参数为提取温度70℃,碱浓度10%,固液比为1∶7,最佳提取率为42.647%;纳米木聚糖的粒径随温度的上升而减小,在60℃条件下,得到纳米级木聚糖的粒径最小,为45.99 nm;试件的载药量随着纳米木聚糖浓度增加,呈现上升趋势;当纳米级木聚糖浓度为10%时,杨木质量损失率在7.63%左右,属于强耐腐级别。     

膜分离技术在低聚木糖制备及乙醇发酵中的应用

综述了膜分离技术在低聚木糖制备及乙醇发酵中的应用。膜分离技术可以用于木糖溶液的脱盐、浓缩和纯化，木聚糖酶解液中低聚木糖的分离，低聚糖的分离和精制，乙醇连续发酵与膜分离耦合，超滤膜反应器中蔗渣的酶水解和酶回收。在低聚木糖制备及乙醇发酵中充分利用膜分离技术对解决污染问题，降低运行成本具有重要的意义。     

Changes of major chemical components in larch wood through combined treatment of drying and heat treatment using superheated steam

The effects of the combined treatment of drying and heat treatment using superheated steam (SHS) were studied relative to the changes of the major chemical components in larch wood. The green lumber was dried and heat-treated in SHS conditions of 250 °C and 0.5 MPa for 18 h, and the relative percentage contents of sugars, lignin, and extractives were investigated and compared with the relative percentage contents in the lumber heat-treated in hot air conditions of 250 °C and atmospheric pressure for 18 h. After both heat treatment methods, the relative percentage contents of xylan, mannan, galactan, and arabinan were greatly decreased, whereas that of the Klason lignin was increased, additionally that of glucan and extractives remained almost unchanged. Lignin may bind with furan compounds decomposed from hemicellulose following heat treatment, thus contributing to the increase in the apparent relative percentage contents of the Klason lignin. In addition, the condensate collected in the condenser after combined drying and heat treatment using SHS was investigated qualitatively and quantitatively by high-performance liquid chromatography (HPLC). A large amount of furfural and acetic acid decomposed from hemicellulose was detected and some sugar components composed of cellulose and hemicellulose were detected in the liquid condensate.     

Spectrophotometric assay of a wood preservative, didecyldimethylammonium chloride (DDAC), in aqueous solution

A spectrophotometric assay based on the color reaction between didecyldimethylammonium chloride (DDAC) and 4-[4-(dipropylamino)phenylazo]-benzenesulfonic acid (propyl orange) was used for the determination of DDAC as a wood preservative. The assay was carried out using a propyl orange solution at pH 2.9. The visible absorbance spectrum of propyl orange showed an absorbance maximum at 510 nm, which decreased continuously with increasing DDAC concentration from 0 to 20 ppm. A linear correlation was observed at a DDAC concentration lower than 8 ppm. To apply this assay method to determine DDAC retention in treated wood, the influence of wood extractives on the assay was investigated. Wood extractives from sapwood and heartwood of Japanese cedar, Hinoki cypress, Japanese larch, and Western hemlock showed no influence on DDAC determination except in the case of heartwood from Japanese cedar and Hinoki cypress, which gave apparent DDAC concentrations higher than the actual values. However, it was also found that absorbance measurement at 477 nm solved this overestimation and gave precise values. It was concluded that this assay is a viable alternative to the current methods for DDAC determination.     

超滤对水飞蓟蛋白酶解物抗氧化活性的影响

采用超滤法从水飞蓟蛋白酶解物中初步分离纯化抗氧化活性肽,考察操作压力、操作温度及酶解物质量分数对超滤过程中膜通量的影响,并对超滤前后水飞蓟蛋白酶解物的抗氧化活性进行比较结果表明:采用截留相对分子质量5 000的聚醚砜膜对水飞蓟蛋白酶解物进行超滤分离的最适工艺条件为操作压力0.1 MPa、操作温度25℃、酶解物质量分数2...     

木聚糖酶在膜反应器内的酶解特性

分别研究了粗木聚糖酶和纯化的木聚糖酶在超滤膜反应器(UMR)和常规反应器(CSBR)中的酶解特性。粗木聚糖酶或纯木聚糖酶在UMR中酶解木聚糖时,反应进行了525 m in时所得产品中低聚木糖各组分的质量分数(木二糖~木五糖)均在20%左右,木糖质量分数约为9.5%。在UMR中粗木聚糖酶降解木聚糖时的低聚木糖得率、低聚木糖占总糖的比例和低聚木糖生产能力比纯木聚糖酶在CSBR中分别高19.1%、14.8%和13.5%;而木糖的得率却低55.2%。粗木聚糖酶在UMR中酶解木聚糖时,所得低聚木糖产品中木二糖~木五糖组分含量基本相等;纯木聚糖酶在CSBR中酶解木聚糖时,所得低聚木糖产品中木二糖含量较高。同纯木聚糖酶在CSBR中酶解特性相比,粗木聚糖酶在UMR中酶解木聚糖可以制得高质量低聚木糖。     

Chemical characterization of Pinus halepensis sapwood and heartwood

ABSTRACT

This paper describes the chemical composition of sapwood (SW) and heartwood (HW) of Pinus halepensis Mill stem. Extractives were first isolated by accelerated solvent extraction and then analysed by gas chromatography-mass spectrometry (GC-MS). The cellulosic polysaccharide content present in the pre-extracted wood samples was determined with acid hydrolysis and GC. The hemicelluloses content was determined with acid methanolysis and GC. Free monomers were additionally analysed by GC. The amount of lignin was determined gravimetrically by the Klason lignin method and the acid-soluble lignin was determined by a UV method. Formic and acetic acids in wood were determined after alkaline hydrolysis and analysed by HP-SEC. It was found that lipophilic and hydrophilic extractives were more abundant in heartwood (1.6% and 2.5%) than in sapwood (1.1% and 1.8%). Celluloses content was higher in sapwood (42.5%) than in heartwood (39.7%), whereas lignin, hemicelluloses and sugar monomer contents were more abundant in heartwood (28.9%, 26.8% and 0.3%) than in sapwood (28.0%, 24.5% and 0.2%). The variation in acetic and formic acids and ash contents between sapwood (0.7%, 0.2% and 0.5%) and heartwood (0.6%, 0.1% and 0.4%) was small. The acetylation degrees were found to be slightly similar in sapwood (0.4) and heartwood (0.3).     

Quantitative comparisons of antitermite extractives in heartwood from the same clones of <Emphasis Type="Italic">Cryptomeria japonica</Emphasis> planted at two different sites

The quantities of some extractives in the heartwood of 25 plus tree clones of Japanese cedar (Cryptomeria japonica) from two different sites were investigated to clarify the differences in antitermite properties in relation to clones and environmental factors. The measured compounds were cubebol, epicubebol, sandaracopimarinol, and ferruginol. The total amounts of extractives were calculated from gas chromatogram peak areas. The heartwoods from Tano (Tano Forest Research Station, Miyazaki University; 31° N, 131° E, 130 m asl) tended to contain more of the individual extractives and total extractives than those from Komenono (Komenono Forest Research Station, Ehime University; 33° N, 132° E, 700 m asl). There was a significant difference (calculated by analysis of variance) at the 1% level among clones at both sites in quantities of total and individual extractives. This result suggests that the qualities and quantities of heartwood extractives are largely affected by genetic factors. Spearman’s rank correlation with the average of the extractive quantities at the sites was investigated. The correlation coefficients of total extractives, cubebol, epicubebol, sandaracopimarinol, and ferruginol were 0.61, 0.85, 0.76, 0.67, and 0.74, respectively. This result means that the order of the amounts of these compounds among the cultivars could be maintained at different sites. It is apparent that both environmental and genetic factors affected the quantities of these extractives in the heartwoods of Japanese cedar.     

纤维素和木聚糖复合诱导合成木聚糖酶的研究

以里氏木霉（Rrichoderma reesei)为产酶菌，分别对纤维素、纤维素和木聚糖诱导产酶的功能进行了研究。研究发现，纤维素具有诱导木聚糖酶合成的功能；纤维素和木聚糖混合对木聚糖酶合成具有促进作用，可大幅度提高木聚酶活力。与纯木聚糖（5g/L)产酶相比，纯木聚糖（4g/L)和纸浆（1g/L)混合产酶木聚糖酶活可以提高45％。研究成果为采用富含木聚糖的植物纤维料作碳源制备木聚糖酶提供了理论依据。