干粉浸提法提取菊粉及树脂脱色工艺研究

采用干粉浸提法从干燥的菊芋颗粒中提取菊粉,石灰-磷酸法除杂,得到澄清的菊粉提取液;利用脱色一号、D280、D296R、D301-G、201-7 5种阴离子树脂和AB-8大孔吸附树脂分别对菊粉提取液进行脱色处理,结果表明,D280型树脂脱色效果最好,综合评分值最高为80.31%,脱色率为84.67%,菊粉保留率为75.9%。通过响应曲面实验探讨菊粉澄清液的pH、质量浓度和温度对综合评分值的影响,并对这3个因素进行了优化。确定树脂脱色的最佳条件为pH=5.11,质量浓度为103.6 g/L,温度为25.43℃。在此条件下综合评分值为95.10%。     

自絮凝颗粒酵母发酵菊芋汁生产乙醇

分别采用分批和连续发酵方式,对自絮凝颗粒酵母Saccharomyces cerevisiae flo发酵菊芋汁生产乙醇的条件进行了优化. 与先酶解菊芋汁后再用自絮凝酵母发酵的分步糖化发酵相比,分批发酵过程中同时加入菊粉酶和自絮凝酵母的同步糖化发酵乙醇得率高,发酵时间短. 当菊芋汁总糖浓度分别为105和179 g/L时,同步糖化发酵的最高乙醇浓度达50和82.5 g/L,比分步糖化发酵高6.4%和13.8%. 在连续发酵过程中应用同步糖化发酵法,当稀释率为0.02 h-1时,乙醇浓度约为90 g/L时达到稳定状态,乙醇得率达到理论值的90%,生产强度达2.12 g/(L×h).     

菊粉季铵盐的合成及性能

该文用菊粉、环氧氯丙烷和十二烷基二甲基叔胺为原料合成了一种菊粉季铵盐表面活性剂。考察了原料摩尔比、催化剂用量、反应温度和反应时间对菊粉季铵盐取代度的影响。最佳反应条件为:n(菊粉)∶n(环氧氯丙烷)∶n(十二烷基二甲基叔胺)=1∶3∶3,催化剂硫酸0.6mL(质量分数26%),70℃反应7h,取代度最高达到1.33。该菊粉季铵盐的CMC=2.78×10-4mol/L,γCMC=29.27mN/m,临界溶解温度Krafft点<0℃,质量浓度3g/L时乳化时间为30min,浓度0.01mol/L时的增溶能力为680mL/mol。与其他生物质资源的阳离子衍生物相比,该菊粉季铵盐具有更强的降低表面张力的能力。     

改性蜂窝煤渣对Cr（Ⅵ）的吸附性能

利用氢氧化钙对蜂窝煤渣进行改性,并通过粉末X射线衍射光谱（XRD）对改性前后蜂窝煤渣的物质组成进行表征,研究了改性蜂窝煤渣对模拟含铬废水中Cr（Ⅵ）的吸附性能。探讨了吸附剂用量、吸附时间、pH值、振荡速率、温度以及Cr（Ⅵ）初始浓度等对吸附效果的影响。改性蜂窝煤渣吸附处理Cr（Ⅵ）的最佳工艺条件是：吸附剂用量40 g/L,室温下以150 r/min振荡速率吸附处理40 min,当Cr（Ⅵ）初始浓度为30 mg/L时,Cr（Ⅵ）的去除率能达到98.84%。改性蜂窝煤渣对Cr（Ⅵ）具有良好的吸附能力,吸附过程符合二级吸附动力学模型并且可用Langmuir吸附等温线来描述。改性蜂窝煤渣对模拟废水中Cr（Ⅵ）的吸附是煤渣组分和新生分子筛组分共同作用的结果。     

D311B型阴离子交换树脂吸附Cr（Ⅵ）的研究及应用

以去除模拟浓缩果汁中的Cr（Ⅵ）为目的,研究了D311B型阴离子交换树脂对Cr（Ⅵ）的吸附性能。实验发现,D311B型阴离子交换树脂在弱酸性条件下（pH在1~4的范围内）对Cr（Ⅵ）具有较强的吸附选择性,等温吸附曲线符合Freundlish等温方程。1.0 g树脂对50 mL浓度为100μg/mL的Cr（Ⅵ）标液的吸附率达74.2%,最大吸附量为3 710μg/g;K＋、Na＋、Ca2＋、Mg2＋、Cl-、SO42-等常见离子等质量浓度对铬吸附无干扰。负载Cr（Ⅵ）的树脂可用1 mol/L的NaCl溶液解吸,解吸后的树脂可再生利用。采用静态吸附方法,0.5 g树脂对50 mL浓度10.0μg Cr（Ⅵ）/mL模拟浓缩果汁,Cr（Ⅵ）的一次去除率可达91.5%。     

基于果糖与葡萄糖不同混合比例的丙酮丁醇发酵

介绍了以不同底物的丁醇发酵结果,阐述了在以55g/L葡萄糖与果糖（1∶4）混合糖模拟菊芋物料为底物的丁醇发酵过程中存在果糖利用及丁醇产量较低等问题,研究了基于葡萄糖与果糖不同混合比例（1∶2、2∶3、3∶2及3∶1）的丁醇发酵性能。研究结果说明了随着混合比例提高,发酵时间由76h缩短至48h,菌体最大生物量OD620由2.1提高至4.3,而当葡萄糖与果糖混合比例为1∶2时,发酵过程中菌体细胞对果糖代谢能力最佳,且终点残糖浓度仅为2.1g/L,果糖利用效率达到95.03%,丁醇及总溶剂产量分别达到9.7g/L与16.0g/L。     

菊粉季铵盐的复配性能研究

考察了菊粉季铵盐与十二烷基硫酸钠(SDS)复配体系的表面化学性质,计算了二者在混合胶束和表面吸附层中的协同作用参数。结果表明,复配体系的表面化学性能明显优于单一体系,在混合胶束和表面吸附层中都表现出强烈的协同效应。当n(菊粉季铵盐)∶n(SDS)=8∶2时,复配体系的临界胶束浓度(CMC)和临界表面张力(γCMC)分别为2.81μmol/L和23.81 mN/m。     

活性白土吸附FCC催化剂胶渣中稀土元素离子的研究

对催化裂化（FCC）催化剂胶渣中有用元素进行回收,不仅实现了资源的回收利用,而且也消除了对环境的污染。以天然膨润土为原料制备得到提纯土,再制备得到活性白土,以提纯土和活性白土为吸附剂吸附催化剂胶渣中的铼离子,考察了吸附条件与性能。结果表明：活性白土对胶渣中铼离子的吸附能力强于提纯土,当活性白土的用量为0.9 g、胶渣溶液中铼离子初始质量浓度为11 mg/L、溶液的pH为4.0、吸附温度为25 ℃时,活性白土对铼离子的吸附率达到93%。该研究为FCC催化剂生产过程中有用元素的回收利用提供了技术支持。     

锰渣-赤泥吸附剂制备及其对铜（Ⅱ）吸附性能

锰渣是锰矿石生产硫酸锰过程产生的酸性过滤渣,赤泥是拜耳法生产氧化铝过程产生的碱性废渣,两种废渣排放量大,综合利用程度低。以锰渣和赤泥为原料,混合焙烧制备锰渣-赤泥吸附剂,实现了两种废渣的中和,制得的吸附剂pH接近中性。研究了锰渣-赤泥吸附剂对溶液中2价铜离子的吸附性能,为废渣的综合利用提供新途径。考察了吸附时间、溶液初始铜离子质量浓度、溶液pH等条件对吸附剂吸附溶液中铜离子的影响。结果表明：不同焙烧温度制得的吸附剂对铜离子的吸附平衡时间为22 h;焙烧温度为700 ℃制得的吸附剂（A700）对铜离子的吸附效果最好,在固液质量体积比（g/L）为0.4∶1条件下,达到平衡时溶液中铜离子的质量浓度可从20 mg/L降低到0.053 mg/L,平衡吸附量为45.739 2 mg/g,对铜离子的吸附去除率达到99.72%。吸附剂A700对铜离子的吸附符合准一级动力学模型和Langmuir等温吸附模型。     

低聚合度木聚糖对木聚糖酶合成的影响

研究了木聚糖的聚合度和添加黄豆粉对里氏木霉合成木聚糖酶的影响,并以纯化木聚糖酶水解木聚糖。研究结果表明:木聚糖经酶水解后平均聚合度降低54%,戊聚糖含量为75.4%。采用低聚合度木聚糖为底物碳源和添加黄豆粉都可提高产酶效果。以12g/L低聚合度木聚糖添加2g/L黄豆粉,培养3d后木聚糖酶活力可达到113IU/mL,提高49.3%。通过对木聚糖酶进行纯化处理可以有效除去β 木糖苷酶。以体积分数10%的木聚糖酶水解35g/L木聚糖3h后,低聚木糖得率达到35.5%,而木糖得率仅为1.5%,低聚木糖与总糖的比值达到95.8%,随着酶解时间的延长,低聚木糖不会被降解。     

菊芋菊糖活性炭脱色的工艺条件

对菊芋菊糖提取液活性炭脱色工艺条件进行了研究,比较了几种不同厂家生产的不同规格的活性炭对菊芋菊糖提取液的脱色效果. 结果表明,仅粉末状活性炭TS4具有脱色作用,且脱色效果显著. 通过单因素实验和正交实验确定的菊芋菊糖提取液活性炭TS4脱色的最佳工艺条件为活性炭用量5 g/L,脱色温度80℃,pH值6.0,时间30 min. 在此条件下,脱色率达82.6%,菊糖回收率可达93.4%.     

Hydrolysis of topinambur (Jerusalem artichoke) fructans by extracellular inulinase of Kluyveromyces marxianus var. bulgaricus

Extracellular inulinase from Kluyveromyces marxianus var. bulgaricus catalysed the hydrolysis of pure inulin and the extracts of fresh and dried topinambur (Jerusalem artichoke). At an enzyme concentration of 10 IU g^?1 of substrate the three substrates were hydrolysed respectively to 65–3, 77–3 and 83–9%. The relationship between the extent of hydrolysis, reaction time and enzyme concentration was studied and a kinetic model of hydrolysis was derived.     

Inulin hydrolysis to fructose by a novel catalyst

Acidic zeolite LZ-M-8 was used to catalyse the hydrolysis reaction of inulin into fructose. Fructose contents of 96% and 75% were obtained when commercial inulin and Jerusalem artichoke extract were used respectively as substrates. Zeolite LZ-M-8 was found to be extremely selective towards inulin hydrolysis as compared to fructose decomposition. Formation of hydroxymethyl furfural (HmF) was not detected and it was confirmed that zeolite LZ-M-8 does not adsorb HMF. The catalytic activity of the zeolite remained intact upon repeated use of the catalyst. The superiority of the zeolite over other catalysts used in inulin hydrolysis was demonstrated experimentally.     

Production and properties of Aspergillus niger inulinase

An inulinase producing Aspergillus niger strain was isolated from Compositae rhizosphere soil samples. High inulinase levels were produced on a corn steep liquor (CSL)-maltose medium in the absence of inulin at 28°C within 110 h of fermentation. Media based on CSL-sucrose yielded high cell-bound inulinase activity; on inulin-based media the enzyme was mainly extracellularly produced. Both crude extra-and intracellular inulinase preparations displayed identical pH and temperature optima with maximal activity at pH 4.3–4.4 and at 55–56°C. These properties are favourable in view of large scale inulinase application for pure fructose production. High operation temperatures would avoid microbial contamination of reactors and would allow the use of high inulin-substrate concentrations, a limiting factor in obtaining high conversion ratios. The remarkably low pH optimum prevents colour formation and undesirable chemical side reactions. An advantageous low ratio of invertase to inulinase activity (S/I value) of 0.85 was found for the crude extracellular enzyme preparation. Crude inulin (chicory) extracts are hydrolysed faster than pure inulin. Apart from inulin (100% hydrolysis), sucrose (45%) and raffinose (20%) are also hydrolysed, and no liberation of oligomers or of sucrose from inulin was observed. These facts indicate that the A. niger enzyme is an exo-acting inulinase. The above characteristics make this A. niger inulinase an industrially attractive enzyme for the preparation of pure fructose from inulin-containing agricultural crops.     

Optimization of the main liming process for inulin crude extract from Jerusalem artichoke tubers

A three-stage homogenate extraction was used as a new method for inulin extraction from Jerusalem artichoke tubers. Compared with the results from conventional hot water extraction, the three-stage homogenate extraction gave higher yields and caused less degradation of the inulin. The inulin crude extract was then clarified by a carbonate-precipitation method, during which three variables — the quicklime mass, the reaction temperature and the reaction time were optimized for the main liming process to give the best clarification effect. A Plackett-Burman design, the path of steepest ascent method, a Box-Behnken design and response surface methodology (RSM) were employed in the experimental design. The optimal conditions for the main liming process were determined to be 12.0 g/L, 71.4°C and 8 min. The confirmatory tests proved that the best clarification efficiency (92.74%) was achieved at these conditions and this was approximately equal to the value predicted by the model.     

能源植物菊芋制备生物基化合物研究进展

生物质作为工业填料在制备化学品的过程中具有可再生性、碳元素利用平衡等优点，但大部分能源植物存在来源于粮食必需品、与农作物争夺优质土地的问题。天然生物质菊芋因具有优良的生长特性、糖类组分含量高、单体官能团多样等特点，被认为是未来最重要的非粮能源植物之一。本文介绍了通过物理过程、生物过程及化学过程等不同途径高附加值化菊芋的研究进展，总结不同方式制备生物基化合物的特点。基于菊芋主要因其根茎中含有丰富的不易被人体消化的菊糖、果糖基多糖聚合度低、组成多糖和还原糖的碳源单体高度单一等优点，着重介绍目前菊芋根茎作为底物制备生物基化合物的过程，分析了通过化学催化法或发酵法制备多元醇、5-羟甲基糠醛、乳酸酯等产品的反应条件、催化剂或生物酶的类型等。基于菊芋秸秆中富含纤维素、半纤维素和木质素等木质纤维素的优势，简述了以纤维素和半纤维素类碳水化合物和木质素的主要研究现状，以及对菊芋秸秆直接催化转化的效果，突出菊芋秸秆转化的优势，提出菊芋秸秆作为底物高效制备目标产物的改进措施。对菊芋根茎和菊芋秸秆的高附加值化过程和效果的分析表明，加强对非粮能源植物菊芋的深加工与生物、化学转化技术的研究，配合生物法与化学法相结合的手段，能加快菊芋工业化应用取得实质性的进展。     

Characterisation of biocatalysts immobilised in niobium—a new inorganic solid support

A new support for enzyme immobilisation, an alloy of niobium ore and graphite, was tested with: invertase from baker's yeast and inulinase from Aspergillus niger. The efficiency of immobilisation was about 30% for invertase and 72% for inulinase. The maximum activities values were observed for both enzymes at: pH 4.5, 50°C and 500 g/L of sucrose. The hydrolysis of inulin (5% w/v) by the free inulinase and invertase presented specific productivity of reducing sugars lower after immobilisation, about 15 and 1.5 times, respectively; with the hydrolysis of sucrose (50% w/v) the reductions observed were of 14 and 3.5 times, respectively. © 2012 Canadian Society for Chemical Engineering     

环氧氯丙烷改性花生壳吸附水中Cu~(2+)的研究

利用环氧氯丙烷对花生壳改性制备吸附剂,并用其吸附水溶液中Cu2+。实验结果显示,花生壳的改性条件为:花生壳5.0 g,浓度为1.5 mol/L NaOH溶液100 mL,环氧氯丙烷5 mL,反应温度30℃,反应40 min;用上述条件改性花生壳0.3 g,吸附初始浓度50 mg/LCu2+溶液,控制溶液的pH为5.0,吸附时间3.0h,对Cu2+吸附率可达96.0%,高于未改性花生壳的70.4%,使吸附率提高36.4%。     

Inulin as a Promising Alternative Feedstock for Docosahexaenoic Acid Production by Schizochytrium sp. ATCC 20888

Schizochytrium sp. is considered as a promising alternative commercial source of docosahexaenoic acid (DHA), but the production is hindered by the high feedstock cost. In this study, inulin is used as a cheap and readily available feedstock for Schizochytrium sp. ATCC 20888 to produce DHA. The strain could not utilize inulin directly and therefore inulin first needed to be hydrolyzed. Compared with the acidic hydrolyzate by HCl and hydrolyzate by endo‐inulinase, the hydrolyzate by exo‐inulinase serves as the most effective carbon source for microalgal growth. Hydrolysis of inulin by exo‐inulinase is further optimized, and up to 97.8% of inulin conversion is obtained under the optimal conditions of 40 °C, pH 7.0, substrate concentration of 80 g L^?1 and exo‐inulinase loading of 2 g kg^?1 substrate for 12 h. The resulting hydrolyzate containing mainly fructose is used for the DHA production by the microalga. The lipid content in biomass, DHA content in total fatty acids, DHA yield, and DHA productivity at 72 h reach 45.26%, 35.59%, 5.64 g L^?1 and 1.88 g L^?1 d^?1, respectively. The results suggest that inulin is an excellent feedstock for Schizochytrium sp. suitable for commercial DHA production. Practical Applications: DHA is an essential nutrient for human health and is widely used in infant formula and functional food. As a reserve carbohydrate, inulin present in plants represents a cheap, abundant, and readily available bioresource. This study describes the suitability of inulin as a promising alternative to glucose for DHA production by Schizochytrium sp. Hence, a practical bioprocess for commercial DHA production from inulin by Schizochytrium sp. could be developed. As far as it is known, this is the first report of inulin as a feedstock for Schizochytrium sp. to produce DHA.