丙酮／丁醇萃取发酵及动力学研究

研究了用油醇为萃取剂进行丙酮/丁醇游离细胞间歇和补料间歇萃取发酵过程。结果表明,萃取发酵可以减轻产物对微生物的抑制作用,提高初始底物浓度,增加发酵速率。建立了间歇萃取发酵的动力学模型,该模型能够描述在间歇萃取发酵过程中底物、微生物、产物及pH的变化规律。     

汽爆秸秆膜循环酶解耦合丙酮丁醇发酵

利用新型的汽爆玉米秸秆膜循环酶解耦合发酵系统进行了丙酮丁醇发酵的研究,并对使用该系统所导致的丙酮丁醇梭菌(Clostridium acetobutylicum AS1.132)代谢的变化进行了讨论. 在稀释率为0.075 h-1的条件下,丁醇的产量为0.14 g/g (纤维素+半纤维素),最大丁醇产率达到0.31 g/(L×h),溶剂组成为丁醇:丙酮:乙醇65.3:24.3:10.4(体积比),纤维素和半纤维素的转化率分别为72%和80%,使用单位纤维素酶所产生的丁醇量为3.9 mg/IU,是分步水解批次发酵的1.5倍. 利用该系统使酶解和发酵分别在各自最适的条件下同时连续进行,减少了纤维素酶的用量,有效地解除了酶解产物对纤维素酶的抑制作用,并减轻了溶剂产物尤其是丁醇对微生物活性的影响,延长了发酵周期.     

木薯干原料同步糖化发酵生产乙醇

提出了用木薯干为原料,同步糖化发酵(SSF)开发燃料乙醇的新工艺. 对各个影响条件进行了研究,获得了最佳的工艺条件：原料粉碎粒度0.45 mm,加水比2.8, 100℃下蒸煮30 min,a-淀粉酶、糖化酶的添加量分别为10, 180 U/g, 30℃下发酵48 h. 并与普通的先糖化后发酵(SHF)生产模式进行了对比,认为SSF具有工艺简单、能耗低、发酵迅速、醪液酒精度高等众多优点,值得工业推广.     

纤维素热解液发酵制乙醇

纤维素热解液中的主要产物是1,6-脱水-b-D-吡喃葡萄糖(简称内醚糖)，通过催化水解内醚糖和脱毒处理，热解液可直接发酵产乙醇. 研究结果表明，在121℃和0.2 MPa条件下的多种催化处理中，0.2 mol/L硫酸处理的热解液获得的葡萄糖产量最高，达17.35%. 水解后含葡萄糖的热解液经Ca(OH)2中和、硅藻土吸附处理，能被Candida krusei YZ-1发酵为乙醇，产率为0.42 g/g(乙醇/葡萄糖), 达理论产率的84%. 而Zymomonas mobilis对于各种处理液的发酵结果都很差.     

Controllability Analysis of Process Alternatives for Biobutanol Purification

Biobutanol has characteristics similar to petroleum fuel and is considered as a superior biofuel compared to ethanol. The development of technologies for biobutanol production by fermentation has resulted in higher final biobutanol concentrations together with less energy‐intensive separation and purification techniques. These new technological developments have the potential to provide a production process for biobutanol that is economically viable in comparison to the petrochemical pathway for its production. The control properties of four different possible process designs for biobutanol purification are analyzed. The results, using the singular value decomposition technique, indicated that the scheme where only biobutanol flow is purified, and both ethanol and acetone leaving the purification process mixed with water and biobutanol traces, showed the best control properties.     

乙醇发酵菌种的选育及发酵条件的初步探索试验

对5种燃料乙醇发酵菌种进行了选择,对较好菌种做了耐高温驯化及发酵条件的优化。结果表明,在以葡萄糖为单一碳源的发酵中,相对于休哈塔假丝酵母、嗜单宁管囊酵母、间型脉胞菌、好食脉孢菌,酿酒酵母种液制备时间最短(对数生长期在6～13 h),发酵制取乙醇得率最高;对酿酒酵母驯化后,得到一株可在42℃正常生长的菌株;经研究,该耐高温菌株的较优发酵条件为温度30℃、转速150 r/min、初始pH值5.0、接种量10%。该耐高温驯化后的酿酒酵母不能直接用于水解液发酵制乙醇,还需要经过驯化或菌种改良后方能使用。     

N, O-羧甲基壳聚糖复合纳滤膜的制备及其对酒厂发酵废水的截留效果

N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone （PSF） composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand （CODcr）, total organic carbon （TOC）, and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODcr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h ooeration for the fermentation effluent treatment.     

橡子粉同步液化糖化产燃料乙醇的发酵条件优化

以除去单宁的橡子粉为原料,应用活性干酵母同步液化糖化发酵(SLSF)制备燃料乙醇,并通过单因素试验和正交试验优化发酵条件。结果表明,同步液化糖化发酵技术适用于橡子粉发酵制备燃料乙醇;发酵的最佳条件为:除去单宁的橡子粉20 g,料液比为1:3(g:mL),淀粉酶100 U/g,糖化酶3 750 U/g,活性干酵母1.50%;在30 ℃静止发酵120 h,发酵液中的乙醇质量浓度达到106.5 g/L,橡子淀粉的乙醇转化率达到89.36 %。采用橡子粉发酵法制备燃料乙醇与以玉米等粮食作物为原料制备的燃料乙醇质量浓度相当,可以替代粮食作物生产燃料乙醇。     

蒸汽爆破处理胡枝子的同步糖化发酵制备乙醇研究

胡枝子茎杆在210℃蒸汽爆破处理2、4、6min,然后进行同步糖化发酵制备乙醇.其乙醇的产率分别是理论产率的59.3%、72.8%和62.2%(未爆破处理的胡枝子茎杆乙醇产率为理论产率的16.4%).研究表明,经过蒸汽爆破处理后胡枝子纤维素的利用率大幅度提高,爆破处理后乙醇产率比未爆破处理的乙醇产率提高了4.65倍.     

原核表达融合型血管生成抑制剂Kringle 5发酵条件的优化和初步纯化

在构建融合型Kringle 5原核表达重组菌BL21(DE3)pET32a/K5的基础上,通过改变培养基的成分,确定了适宜于重组菌生长和融合Kringle 5蛋白表达的培养基.采用正变实验方法,对融合型血管生成抑制剂Kringle 5原核表达重组菌的发酵条件进行了优化,通过发酵罐中重组菌的分批培养,确定了培养液中的最佳溶氧量.采用优化后的发酵工艺,在20 L发酵罐中融合Kringle 5的表达量可达0.59 g·L-1.最后在Cu2 螯合的Sepharose Fast Flow层析介质上对融合Kringle 5进行了初步纯化,其纯度约为80%.     

螺旋霉素发酵液不同过滤洗涤方式的对比研究

用板框压滤机进行发酵液的过滤是目前发酵液处理的主要手段。但国内各厂家在过滤洗涤时都采用置换洗涤法 ,大大增加了洗涤水的用量 ,也影响了收率。研究表明 ,改用横穿洗涤法进行洗涤可以使洗涤液体积减少一半 ,提高了过滤收率 ,同时减少了溶媒损耗和产品损失 ,并降低了滤饼含水量 ,取得了明显综合经济效益     

Limitation of the Coalescence of Evolutive Droplets by the Use of Copolymers in a Thermoplastic/Thermoset Blend

Summary: Polystyrene (PS)/epoxy‐amine (DGEBA‐MDEA) is a thermoplastic/thermoset precursor blend which is miscible at high temperature (177 °C), and which phase separates under the polymerization of the epoxy‐amine system. Previous studies have shown that the morphology of this blend polymerized under shear is coarse and irregular because the dispersed epoxy‐amine domains coalesce before they gel. Several styrene‐methyl methacrylate and a styrene‐butadiene‐styrene block copolymers have been added to the PS/DGEBA‐MDEA 60/40 blend in order to limit the coalescence and thus obtain a finer morphology. Two of the copolymers used were reactive either with the epoxy or with the amine. It was shown that the addition of 15 wt.‐% of non reactive copolymer had a positive but limited effect on the size of the final epoxy‐amine particles. The copolymer remained at the interface at the early stages of the polymerization. However, it was pulled out by the shear forces around the gel point of the epoxy domains. Most of the non reactive copolymer was present in the shape of micelles at the end of the process. On the other hand, the reactive copolymers were able to establish covalent bonds with the epoxy‐amine drops and hence were not extracted at all. Consequently they allowed the decrease the size of the particles by a factor of 15. Despite this, the observation of the morphology at different stages of the polymerization has revealed that the copolymer moved at the interface of the epoxy domains during the collision of two droplets. The movements of fluids into the epoxy domains pushed the copolymer out of the inter‐droplet zone so that it could not prevent the drainage of the liquid film between the droplets and consequently their coalescence.

TEM showing that the layer of copolymer (in dark grey) has moved along the interface of epoxy‐amine drops during their successful collision in a polystyrene‐rich matrix.     

Combustion and Agglomeration Characteristics of the Residue from Corn Stalk‐Based Cellulosic Ethanol

Lignocellulose is considered an efficient raw material to produce fuel ethanol. Clean utilization of the solid residue derived from lignocellulose‐based fuel ethanol is important for the biomass‐to‐ethanol production chain. Combustion characteristics of the residue originating from corn stalk‐based cellulosic ethanol are studied in a circulating fluidized bed. Results indicate that circulating fluidized‐bed combustion is an effective and stable way to burn the residue with high moisture content. CO emission during biomass combustion in a circulating fluidized bed is low in the range of several ppm. NO and N₂O are the major pollutants during residue combustion. The optimal combustion temperature is limited to avoid agglomeration and reduce pollutant emission. Design data and theoretical support for design and operation of the residue combustion circulating fluidized‐bed boiler are provided.     

玉米芯HNO_3/HCl预处理及同步糖化发酵制乙醇

采用正交实验对玉米芯在2%HNO3/HCl中的水解条件进行优化,得出最适宜的预处理条件为：反应温度120℃,反应时间30 min,固含量15%。将经过预处理的玉米芯作为同步糖化发酵的底物,采用单因素实验考查影响发酵的因素,结果表明：在底物浓度为150 g/L、37℃、pH值为5.0、纤维素酶用量为30 FPU/g底物、酵母接种量10%、发酵周期72 h时,乙醇的产率可达到76.8%,此时乙醇溶液的浓度为41.4 g/L。     

Expert System for the Design of an Industrial Fermentation Plant for the Production of Alcohol

A user-friendly expert system was developed for the design of large scale continuous fermentation units for alcohol production. This expert system utilized an intensive rule-based program, with a knowledge base structured using both expert knowledge data and industrial practices, as well as computer simulations. The simulation algorithm was developed from mass and energy conservation of continuous multi-staged plants and kinetic equations representing the fermentation process by Saccharomyces cerevisiae. The kinetic parameters were adapted from industrial data, leading to a reliable mathematical model that represented the industrial process reasonably well. Since the system was designed for continuous processes with several stirred tanks connected in series, the optimal volume profile and number of stages were previously optimized. The system developed could be utilized either for the design of industrial plants or for the improvement and modernization of existing plants. This system was shown to be reliable since the difference between theoretical calculations and practical results was minimal. © 1997 SCI.     

糠醛渣直接同步糖化发酵生产乙醇过程比较研究

以糠醛渣为原料,直接同步糖化发酵(SSF)生产乙醇,并与水洗糠醛渣生产乙醇进行对比。通过考察不同条件来优化同步糖化发酵生产工艺条件,并分析表征了SSF过程中乙醇浓度和副产物浓度变化。优化条件为:糠醛渣底物质量分数10%,纤维素酶用量12%,无患子皂素质量浓度0.5g/L,酵母接种量7g/L,同步糖化发酵乙醇得率达到其理论得率的93.1%。与水洗糠醛渣相比,糠醛渣直接SSF过程可将原料吸附的5.50%葡萄糖部分转化为乙醇。水洗糠醛渣SSF生产乙醇所产生的副产物要远低于糠醛渣直接生产所产生的副产物,添加无患子皂素可有效抑制糠醛渣同步糖化发酵过程中副产物的产生。     

玉米芯稀酸预处理和分步糖化与发酵工艺生产燃料乙醇的中试研究

利用正交试验在中试水平考察了玉米芯的稀硫酸预处理和分步糖化与水解生产乙醇的工艺。结果:最佳预处理工艺为稀硫酸浓度1.1%,温度120℃,固液比1∶8,时间3 h;酶解糖化最佳工艺为:起始底物浓度180 g/L,滤纸酶活:纤维二糖酶活=20 IU/g底物:7 IU/g底物,pH=5.0,48 h;利用运动发酵单胞菌发酵酶解液,35℃,48 h,发酵液中乙醇浓度最高67.8 g/L。     

EPDM／CPE并用胶料的阻燃性与电绝缘性研究

主要探讨了ＥＰＤＭ／ＣＰＥ并用比、阻燃剂（Ｓｂ２Ｏ３、十溴联苯醚）的配比、填料品种及用量、硫化剂ＤＣＰ及助交联剂ＴＡＩＣ等因素对ＥＰＤＭ／ＣＰＥ并用胶料力学性能、阻燃性能及电性能的影响,结果表明：选择ＥＰＤＭ４０,ＣＰＥ６０．３ＰｂＯ１．２,２ＰｂＯ１．２,ＤＣＰ２～３,ＴＡＩＣ１,滑石粉３０,Ｓｂ２Ｏ３１０～１５,ＺＲ－１０２０～３０,ＳＡ１,ＺｎＯ５,可制得综合性能较好的ＥＰＤＭ／ＣＰＥ并用胶     

Performance of a Pinch Analysis for the Process of Recovery of Ethanol from Fermentation

The objectives of the project reported here were to perform an energy analysis for the process of the recovery of ethanol from fermentation broths by catalytic conversion to gasoline and to conduct a pinch analysis to obtain a new heat exchanger network, and thus, reduce the utility costs. A minimum temperature difference of 10 °C was used. A temperature interval diagram and cascade diagram were drawn to identify the pinch points and four such points were observed. New heat exchanger networks were formulated from this information. The least number of heat exchangers for the different networks created was 19, whereas the original process had 9. The cost of utilities was the same for both systems. Therefore, it was concluded that the implementation of this system in the Caribbean could be expensive since in the first instance, ethanol is not particularly plentiful. Secondly, electricity and water costs are expensive in the Caribbean compared to other countries in America, such that any effort in reducing CO₂ emissions by using ethanol would not be feasible.     

硫酸净化工序污水在磷酸过滤机上的应用

用硫酸装置净化工序排放的污水代替工艺水,作为磷酸生产萃取工序真空过滤三洗水,介绍了运行情况及完善措施,通过运行试验实现了污水零排放,达到了环境保护和清洁生产的要求.