以菊芋粉为原料同步糖化发酵生产燃料乙醇

利用粟酒裂殖酵母（Schizosaccharomyces pombe）能发酵菊芋未水解糖液高产乙醇的特点提出了以菊芋粉为原料,同步糖化发酵生产燃料乙醇的新工艺。在摇瓶中考察了原料预处理方法、原料浓度和初始pH值对乙醇发酵的影响,进而在5 L发酵罐中考察了未调控pH值和恒定pH值与通气情况对乙醇发酵的影响。结果表明：该菌株最适pH值为4.0;100目筛分的菊芋粉发酵效果良好,115℃灭菌处理优于121℃,在此条件下,菊芋粉浓度200 g/L时,乙醇产量达到66.58 g/L,理论转化率为85.88%;发酵液pH值下降对乙醇发酵没有影响,通入适量氧气会导致乙醇产量的下降,这表明粟酒裂殖酵母进行乙醇发酵时不需要供氧;通入氮气保持厌氧环境不能显著提高乙醇产量,不通气进行乙醇发酵也达到高的转化率,因此在工业生产中,不必保持厌氧发酵环境。在此基础上,对菊芋粉补料发酵进行了试验,补料至菊芋粉终浓度为300 g/L,发酵终点乙醇浓度为94.81 g/L,理论转化率为81.54%。这些研究工作,为以菊芋为原料的燃料乙醇工业化生产提供技术依据。     

生物油酯化-加氢提质制备醇酯类燃料

作为清洁可再生的化石燃料取代燃料,生物油的酸性及不稳定性是阻碍其规模化应用的主要障碍之一。该文基于生物油高酮、醛及酸类含量,研究了生物油轻质组分分步酯化加氢(SHE,separated esterification and hydrogenation)、一步酯化加氢(OEH,one step esterification-hydrogenation)及一步酯化加氢后二次加氢(OEH plus,one step esterification-hydrogenation plus second hydrogenation process)的提质过程,考察了钼改性雷尼镍催化剂(Mo-RN,Mo-Raney Ni)及Ru/C催化剂催化生物油制备醇类燃料的重复使用性能,并研究了酯化-加氢反应过程及反应路径。结果表明,生物油经不同酯化-加氢方法处理后,饱和醇酯含量均显著提高,生物油品质得到改善。其中以OEH plus提质处理后的生物油产物中,饱和醇、酯含量最高,分别达74.21%和9.96%。此外,提质后的生物油p H值及酸量下降最为显著,生物油的p H值由反应前的3.67提高到5.88,酸量由111.52 mg/g降至11.75 mg/g。Mo-RN及Ru/C催化剂在酯化-加氢路径下的重复使用性能良好,催化活性均无明显降低。试验证明利用酯化-加氢提质生物油为生物油精制制备含氧燃料提供有效途径。     

以马铃薯为辅料的黄酒发酵条件优化

采用响应面方法对以马铃薯为辅料的黄酒发酵条件进行了优化。通过单因素试验、正交试验及中心组合试验优化得到以马铃薯为辅料酿造黄酒的最佳发酵条件为：酵母添加量0.114%(原料量的0.114%)、主发酵温度28℃、麦曲添加量14.0%(原料量的14.0%)、料水比1∶0.7、每100 g原料添加425μL糖化酶、发酵初始pH值4.0。在优化得到的发酵条件下酿造得到的以马铃薯为辅料的成品黄酒，其酒精度、酸度、色、香、味等各项理化指标和感官指标均符合国家黄酒标准GB/T 13662-2000，成品酒的感官品质得到了改善，且所含游离氨基酸含量为7063.4 mg/L，是普通黄酒游离氨基酸含量的1.2～2.5倍。     

CLC-St-PAM絮凝剂净化蔗渣制浆黑液回收木质素

该文通过制备耐酸型絮凝剂,以酸析絮凝法处理蔗渣制浆黑液高效回收木质素。首先以木薯淀粉、5-羟甲基糠醛以及3-氯-2-羟丙基三甲基氯化铵为主要原料制备交联阳离子淀粉(cross-linked cationic starch,CLC-St),然后以CLC-St为骨架与丙烯酰胺在引发剂作用下进行接枝共聚反应,合成了交联阳离子淀粉接枝聚丙烯酰胺(cross-linked cationic starch grafted polyacrylamide,CLC-St-PAM)絮凝剂,并通过红外光谱、X射线衍射和扫描电子显微镜等手段对CLC-St-PAM进行结构和形貌分析。结果显示,交联阳离子淀粉分子与丙烯酰胺成功发生了接枝共聚反应,反应主要发生在淀粉颗粒表面,接枝产物呈现为无定形的聚集态。以CLC-St-PAM为絮凝剂处理p H值为2~7间的蔗渣碱法制浆黑液,系统考察了p H值、CLC-St-PAM用量等因素对木质素的回收率、滤液中酸溶木质素含量和化学耗氧量(COD)的影响,结果表明,酸析-絮凝处理可以有效的去除制浆黑液中的酸不溶木质素、酸溶木质素以及COD,在p H值为2时投入0.015 g/L的CLC-St-PAM,木质素回收率高达89.02%±0.54%,COD去除率也达69.06%±1.42%;同时,酸溶木质素质量浓度由原来的(0.561±0.021)g/100 m L下降至(0.187±0.008)g/100 m L,黑液由原来的棕黑色变为清澈的淡黄色。不同p H值回收得到的木质素结构通过核磁共振氢谱和凝胶渗透色谱表征,结果表明酸析-絮凝过程中首先析出来的是相对纯净的木质素分子,随着体系p H值的进一步下降,更多与半纤维素通过稳定的共价键形成的木质素-半纤维素复合体也逐渐沉淀析出。     

废弃食用油脂两相厌氧发酵酸化条件优化

油脂的水解和长链脂肪酸的降解是油脂厌氧发酵过程中的限速步骤,提高水解酸化阶段挥发性脂肪酸(volatile fatty acid,VFA)的产率,有助于后续甲烷化反应的进行。利用响应面方法(response surface methodology,RSM)对废弃食用油脂两相厌氧发酵水解产挥发酸条件进行优化,考察了初始p H值、原料负荷、反应时间和接种量对产生挥发酸浓度的影响,提出采用该工艺的数学模型及优化后的工艺参数。结果表明,各影响因子对挥发酸的影响顺序为:接种量反应时间原料负荷初始p H值,方程的F值为15.65,相关系数为0.9359,调整相关系数为0.8761,说明数学模型可以较好地模拟真实的反应曲面。优化得到最佳的工艺参数为初始p H值6.2、负荷300 g/L、反应时间8 d、接种量40%,在该条件下,实际产挥发酸7 221.0 mg/L,与预测值7 224.0 mg/L吻合且重现性较好。厌氧产甲烷试验表明,酸化后废弃油脂较未酸化油脂在甲烷产量、甲烷含量、总化学需氧量(chemical oxygen demand,COD)去除率及挥发性固体(volatile solid,VS)去除率方面分别提高了44%、11%、28%和51%,经酸化处理比未酸化油脂的厌氧发酵时间(完成一个厌氧发酵周期内总产气量的80%的时间)缩短了28%。该研究结果为废弃食用油脂的两相厌氧发酵中试提供了参考。     

甜高粱茎秆固态发酵生产燃料乙醇研究

该文通过研究甜高粱茎秆M-81E固态发酵生产燃料乙醇的主要影响因素,确定发酵条件为:耐高温酿酒酵母接种量为3%,发酵初始基质含水率为76%,添加0.25?Cl2,0.25%MgS04·7H2O,40℃发酵24 h,乙醇得率为6.42 g/(100g)甜高粱茎秆,转化率为90.5%,残糖含量低于0.3%;添加10 FPU/g纤维素酶和10 CBU/g β-葡萄糖苷酶,进行同步糖化固态发酵,乙醇得率为7.53 g/(100 g)甜高粱茎秆,与不添加纤维素酶和β-葡萄糖苷酶的相比,乙醇得率提高了14.6%.     

Raney-Ni催化生物油轻质组分加氢制备含氧燃料

鉴于生物油的高含氧量,将其轻质组分在温和条件下转化为以饱和醇为主要成分的含氧燃料可能成为生物油利用的新思路。该文以自制Raney-Ni为催化剂,研究在高压反应釜中反应温度（100～180℃）、氢气冷压（4～8 MPa）、催化剂用量（0.5～2 g）对生物油轻质组分催化加氢改质的影响;对Raney-Ni催化剂进行N2吸附脱附、X射线衍射（X-ray diffraction）、扫描电镜（scanning electron microscope）表征,分析催化剂失活机理,研究催化剂的重复使用性能。试验结果表明：反应温度和反应初压对生物油加氢产物分布的影响较大,在反应温度为140℃、氢气初压为6.0 MPa 时,产物中饱和醇的相对含量（以GC峰面积百分比计算）最高可达53.51%;当催化剂用量从0.5 g增加到1 g时,产物中饱和醇的含量显著提升,由25.42%提高到51.89%,进一步提高催化剂用量对饱和醇含量的提高影响不大;一次与二次催化剂催化生物油加氢反应产物中饱和醇含量由53.51%降为29.20%,活性显著降低可能与催化剂孔道内部及表面的活性中心被覆盖进而降低反应效率有关。加氢过程中,除有酮醛酚类化合物的加氢反应和酸与醇的酯化反应外,存在醇脱水成醚的反应发生。与烃类液体燃料相比,含氧燃料以其优异的燃烧性能逐渐被人们所青睐。将生物油的轻质组分加氢制备含氧燃料有望成为生物油的应用提供新思路。     

废鸡油脂制取生物柴油试验研究

生物柴油作为一种绿色清洁替代型燃料,受到科研和产业界的广泛重视,原料油脂的廉价稳定供应是生物柴油产业化的关键.该文对来源于鸡肉制品加工的废鸡油作为生物柴油原料的潜力进行了探索,在NaOH催化剂作用下,通过与甲醇转酯化反应制备生物柴油.试验考察了醇油摩尔比、NaOH用量、反应温度、反应时间等因素对油脂转化率的影响,并对制备的生物柴油样品进行了燃料指标分析.结果表明,炼制鸡油较为适宜的转酯化反应条件为反应温度50℃、醇油摩尔比9:1、NaOH用量1.3%、反应时间90～120 min,获得油脂转化率约90%.试验生物柴油样品多项理化指标能够满足EN14214生物柴油标准及国内O#柴油标准.     

不同碳氮比下牛粪高温堆肥腐熟进程研究

为有效处理奶牛场养殖粪污,建立以之为原料的牛粪有机肥高效堆肥工艺,本文通过工厂堆肥试验,以牛粪为主料,以蘑菇渣、稻壳为辅料,设置C/N=15、C/N=25、C/N=35三个处理,研究不同碳氮比原料高温堆肥过程中堆体温度、pH值、EC、C/N和养分等理化指标的变化。结果表明,C/N=25堆体达到的温度最高,达到最高温度所需时间最短且保持65℃以上时间最长。堆肥过程中各处理pH值变化基本一致,均是先升高后降低再升高最后趋于稳定,各处理EC都是先波动上升后在波动中逐渐下降并趋于稳定。各处理堆体在堆肥过程中,C/N也都呈现逐步减小的趋势,并最终保持稳定。至堆肥结束时,各处理C/N分别11.7、15.0和21.3。各处理铵态氮含量逐渐下降,硝态氮含量逐渐增加,至堆肥结束时,铵态氮的损失量分别为80.7%、36.6%和46.7%,硝态氮含量分别增加到0.61 g kg~(-1)、0.50 g kg~(-1)、0.41 g kg~(-1)。堆肥结束时,各处理胡敏酸类、富里酸类等物质成为DOM的主体部分,N1、N3处理发芽指数大于50%但小于85%,N2处理发芽指数大于85%。各处理堆肥全磷、全钾含量在堆肥结束时比堆肥初始均有所增加。因此,牛粪高温堆肥能有效处理奶牛场养殖废弃物,且C/N=25时堆肥效果最佳。     

水酶法提取山核桃油脂工艺研究

为优化水酶法提取山核桃油脂工艺,以山核桃为原料,采用水酶法提取油脂,在单因素试验基础上,采用响应面法研究木瓜蛋白酶用量、酶解时间、pH值、酶解温度和料液比对山核桃油提取率的影响;采用气相色谱-质谱联用技术分析提取油脂的脂肪酸组成,并对比了压榨法、溶剂法和水酶法3种方式对油脂理化性质的影响。结果表明,水酶法提取山核桃油脂工艺的最佳条件为:木瓜蛋白酶量0.17%,酶解时间150 min,pH值6.34,酶解温度54.43℃、料液比1∶5,在此条件下山核桃中油脂提取率为81.32%。采用气相色谱-质谱联用技术对提取油脂的脂肪酸组成进行分析,共测出12种脂肪酸,棕榈酸、油酸、亚油酸、亚麻酸是4种主要脂肪酸,其中饱和脂肪酸(SFA)占7.61%,单不饱和脂肪酸(MUFA)占69.10%,多不饱和脂肪酸(PUFA)占23.29%。对比3种提油方式发现,水酶法是一种较为理想的油脂提取方法。本研究结果为水酶法提取山核桃油脂生产提供了理论依据。     

Antioxidant protection of bulk fish oils by dispersed sugars and polyhydric alcohols

Selected sugars (fructose, sucrose, or raffinose) and polyhydric alcohols (sorbitol or mannitol) were equilibrated directly with bulk fish oil (10% by weight, excess) and exposed to fluorescent lighting (2550 Lx) for 24 h at 5 degrees C. Data for room temperature-equilibrated samples revealed that polyols functioned as antioxidants in fish oil. Increased times and temperatures of equilibration (to 90-110 degrees C, 1-2 mmHg, to 2 h) greatly enhanced the antioxidant activity of polyols in fish oil exposed to light. Under accelerated oxidation conditions (60 degrees C) in the dark, dispersed sorbitol in bulk fish oil greatly suppressed the peroxide value, primarily by chelating transition metals, while fructose showed a limited antioxidant activity. Sugars with a lower molecular weight and smaller numbers of equatorial OH groups exhibited a higher rate of permeation of sugars into fish oil triacylglycerols and hence rendered greater antioxidant activities. The treatment of bulk fish oils with polyols and then using the oils in the preparation of emulsions greatly reduced their antioxidant activities as compared to those observed for treated bulk oils. The introduction of polyols dissolved in propylene glycol into bulk fish oils at 90 degrees C (0.025% polyol, 0.25 h of equilibration) provided a similar antioxidant activity to that imparted by the introduction of polyols into the oil by equilibrating excess polyols (10% by weight) with them at 90-110 degrees C for 2 h. However, regardless of the method of the introduction of polyols to bulk fish oil, an elevated temperature (90 degrees C) exposure during fish oil treatment was required to induce a notable antioxidant activity.     

Determination of iodine value by bromine/instrumental neutron activation analysis

A new microanalytical method has been developed to measure iodine value (IV) of oils and fats. Bromine vapor was used to saturate the ethylenic double bonds, and reacted bromine was determined by instrumental neutron activation analysis. The method was applied to measure the iodine values of 7 commercially available vegetable oils: almond oil, sunflower oil, peanut oil, soy oil, sesame oil, corn oil, and olive oil. No significant difference was observed between the iodine value determined by the proposed method and that determined by an officially approved (Hübl) method. Bromine measurements can be performed up to 150 days after bromination with no significant variation in iodine value; thus, availability of an irradiation facility on the premises is not a limitation. No corrosive and toxic reagents are required, and the method is faster than the official methods. The method is also applicable to measuring iodine values of free or esterified fatty acids.     

Improved oil solubilization in oil/water food grade microemulsions in the presence of polyols and ethanol

Microemulsions based on five-component mixtures for food applications and improved oil solubilization have been studied. The compositions included water, oil phase [such as R(+)-limonene and medium-chain triglycerides (MCT)], short-chain alcohols (such as ethanol), polyols (propylene glycol and glycerol), and several surfactants and their corresponding mixtures (nonionic, such as ethoxylated sorbitan esters, polyglycerol esters, sugar ester, and anionic, such as phosphatidylcholine). The phase behavior of these systems is discussed with respect to the influence of polyols and short-chain alcohols on the degree of solubilization of oils in the aqueous phase. The alcohol and polyols modify the interfacial spontaneous curvature and the flexibility of the surfactant film, enhancing the oil solubilization capacity of the microemulsions. The solubilization of R(+)-limonene was dramatically improved in the presence of the alcohol and polyols, whereas the improvement of solubilization for triglycerides containing MCT was less pronounced. In some systems high oil solubilization was achieved, and some of them can be easily diluted to infinity both with the aqueous phase and with the oil phase. Viscosity measurements along selected dilution lines [characterized by a single continuous microemulsion region starting from a pseudo binary solution (surfactant/oil phase) to the microemulsion (water/polyol corner)] indicate that at a certain composition the system inverts from a W/O to an O/W microemulsion.     

玉米秸秆液化制备生物高聚物材料的研究(英)

该研究旨在探讨低温生物质液化技术及液化产物应用的可能性。以玉米秸秆为原料在酸性、常压条件下快速液化成多羟基化合物，再以多羟基化合物为原料合成一系列的聚合材料。采用不同的有机溶剂，在稀硫酸的催化作用下，对不同的温度下生物质的液化效果进行研究。同时探讨了液化有机溶剂同生物质物料的混合比率对液化过程的影响。试验表明，碳酸乙烯酯比乙烯醇具有较高的液化率。优化试验结果表明，在较佳的液化效果下， 有机溶剂同玉米秆的混合比率为3∶1，反应温度160℃，稀硫酸浓度3%，反应时间2.5 h。液化产物经稀释、调节pH值、过滤、臭氧氧化一系列过程的处理后得到具有高活性多羟基聚合物。阐述了以多羟基聚合物制备各种生物聚合物材料如聚酯薄膜、聚胺酯泡沫和颗粒板的方法。聚酯薄膜是多羟基化合物上的羟基和多元酸上的羧基通过酯化反应形成的；聚胺酯泡沫通过多羟基化合物上的羟基和二异氰酸酯反应形成。研究表明以多羟基化合物和多元酸（酐）形成的聚酯型胶粘剂适合于制造颗粒板。     

Hydrogenation and interesterification effects on the oxidative stability and melting point of soybean oil

Soybean oil with an iodine value of 136 was hydrogenated to have iodine values of 126 and 117. The soybean oils with iodine values of 136, 126, and 117 were randomly interesterified using sodium methoxide. The oxidative stabilities of the hydrogenated and/or interesterified soybean oils were evaluated by measuring the headspace oxygen content by gas chromatography, and the induction time was measured using Rancimat. The melting points of the oils were evaluated by differential scanning calorimetry. Duncan's multiple range test of the headspace oxygen and induction time showed that hydrogenation increased the headspace oxygen content and induction time at alpha = 0.05. Interesterification decreased the headspace oxygen and the induction time for the soybean oils with iodine values of 136, 126, and 117 at alpha = 0.05. Hydrogenation increased the melting points as the iodine value decreased from 136 and 126 to 117 at alpha = 0.05. The random interesterification increased the melting points of soybean oils with iodine values of 136, 126, and 117 at alpha = 0.05. The combined effects of hydrogenation and interesterification increased the oxidative stability of soybean oil at alpha = 0.05 and the melting point at alpha = 0.01. The optimum combination of hydrogenation and random interesterification can improve the oxidative stability and increase the melting point to expand the application of soybean oil in foods.     

青花椒真空脉动干燥特性及干燥品质工艺优化

为提升青花椒的干燥品质,减少其色泽褐变和风味物质流失等问题,该研究采用真空脉动干燥技术加工青花椒,并以热风干燥试验为对照组,研究了不同干燥温度、真空保持时间和常压保持时间对青花椒干燥特性及其品质的影响。在单因素试验基础上进行Box-Behnken中心组合试验设计,以青花椒的平均干燥速率、挥发油、酰胺含量、色差、开口率5个指标进行响应面优化分析。试验结果表明,Weibull模型可精确拟合青花椒真空脉动干燥曲线（R2>0.99）。干燥温度升高可在一定程度上提高青花椒的干燥效率和开口率,减少褐变和挥发油损失,同时酰胺类含量随干燥温度上升而有所下降。根据响应面试验结果,各因素对青花椒干燥综合评分的影响效果由大到小顺序为：干燥温度、真空保持时间、常压保持时间。优化的工艺参数为真空脉动干燥温度61.4 ℃、真空保持时间5 min、常压保持时间5 min,综合评分值达8.06,验证试验结果偏差仅为2.6%。研究结果为青花椒真空脉动干燥应用提供参考。     

Study on the Parameters of Extrusion Pretreatment of Corn Germ with Semi‐Wet Milling in Solvent Oil Extraction

Efficiency of oil extraction from corn germ was improved by the extrusion pretreatment, and residual oil was taken as the index of this oil extraction process. An orthogonal rotation combination test design of five levels and four factors, consisting of the moisture of material, screw speed, barrel temperature, and die nozzle diameter, was employed to optimize the model and reaction condition. The optimum parameters of extrusion were as follows: moisture of material, W = 12%; extrusion temperature, T = 105°C; screw speed, n = 185 rpm; die nozzle diameter, Φ = 9 mm × 3. Under these optimum conditions, residual oil of this process was 0.61–0.66%, which was lower than residual oil by pressing alone (residual oil of 5–6%) or by a combination of prepressing and hexane extraction (residual oil of nearly 2%). The corn oil obtained by the optimum extrusion parameters was analyzed, and iodine value, acid value, peroxide value, and saponification value were 1,250 g/kg, 400 mg/kg, 5.1 mmol/kg, and 189%, respectively.     

耦合浮珠-超声辅助溶剂萃取法用于微藻采收及油脂提取

为了优化微藻生物柴油生产工艺,开发高效低耗的微藻采收与油脂提取技术,该研究使用优化浮珠浮选工艺对小球藻进行采收,随后选取小球藻-表面层状聚合物浮珠聚集体进行破壁提油处理,并通过响应面优化破壁工艺,建立一种新型耦合浮珠-超声辅助溶剂萃取工艺。结果表明,在超声时间为13 min,正己烷：异丙醇体积比例为4,微藻质量浓度为13.6 g/L,超声功率为254 W时,油脂提取效率较高,为18.91%。相比传统气浮法与超声辅助溶剂萃取法,该法采收效率、细胞破壁效率和饱和脂肪酸含量都达到了较高水平,分别为98.36%、90.19%和37.03%。因此,耦合浮珠-超声辅助溶剂萃取工艺是一种有效提取小球藻细胞中油脂的工艺。研究结果为微藻生物柴油制备工艺的发展提供科学依据。