Direct isopropanol production from cellobiose by engineered Escherichia coli using a synthetic pathway and a cell surface display system

Efficient bio-production from lignocellulosic biomass is required for the purpose of developing an inexpensive, practical bio-refinery process. As one approach to address this problem, we genetically engineered Escherichia coli to produce isopropanol directly from cellobiose via the cellobiose degradation by Beta-Glucosidase (BGL) on the cell surface. First, we investigated the cellobiose consumption of two E.?coli strains with the BGL protein from Thermobifida fusca YX (Tfu0937) fused to the anchor protein Blc (Tfu0937/Blc) using different fusion sites. Next, we introduced the synthetic pathway for isopropanol production into those strains and compared their isopropanol production in the presence of glucose. Based on the results of these assays, TA212/pTA411, which was introduced Tfu-Blc fused protein expression system and the synthetic pathway for isopropanol production, was selected for the directly isopropanol production from cellobiose. TA212/pTA411 produced 69.0±11.6mM isopropanol at 21h of fermentation, whereas TA212/pTA147, which did not introduced the BGL/anchor fused protein but was introduced the synthetic pathway for isopropanol production, showed no cellobiose consumption and no isopropanol production during fermentation. To our knowledge, this is the first report of the production of a bio-product from cellobiose using E.?coli.     

The extraction of passion fruit oil with green solvents

In the present paper, the extraction of passion fruit oil with acetone, ethanol and isopropanol of passion fruit seeds under three different techniques (ultrasound, shaker and soxhlet) were studied. The influence of seed to solvent ratio, time and type of solvent were investigated during ultrasound, shaker and soxhlet process. Hexane was used as well, as an extraction solvent to evaluate the extraction of oil in all extraction process studied to make a comparison among the employed solvents. The temperature was kept isoterminally at 40 °C in both shaker and ultrasound process. The highest yield when green solvents were was 23.8%, during ultrasound process, with acetone was used. Our results indicate that ultrasound can greatly replace the conventional extraction.     

白花菜籽油的制备及脂肪酸组成分析

采用溶剂浸提法提取白花菜籽油,对其提取工艺条件进行了研究,并用气相色谱法对其脂肪酸的种类和相对含量进行了测定。结果显示,以异丙醇为浸提溶剂,料液比(质量体积比)为1∶7,浸提时间为60 min,浸提温度为60℃时,白花菜籽油的提取率最高为28.4%。利用气相色谱鉴定出14种脂肪酸,主要有亚油酸(62.65%)、油酸(20.66%)、棕榈酸(10.98%)、硬脂酸(4.18%),饱和脂肪酸质量分数为15.68%,不饱和脂肪酸质量分数为84.32%,其中单不饱和脂肪酸质量分数为21.01%,二不饱和脂肪酸质量分数为62.65%,三不饱和脂肪酸质量分数为0.67%。     

从异丙醇装置副产中分离精制异丙醚的工艺研究

采用萃取精馏和共沸精馏的试验方法,进行了从异丙醇装置副产中分离精制异丙醚工艺的研究,结果可以得到纯度大于99%的异丙醚和纯度大于99.5%的异丙醇,并且产率较高。     

Desorption of soy oil lutein from rice hull cristobalite with polar solvents

The effectiveness of sequential isopropanol/hexane washes of increasing polarity for desorbing soy oil pigment (lutein) from alkaline and acid rice hull ash was studied. Increasing the polarity promoted desorption of pigment. However, the amount of pigment desorbed with each extraction decreased after washing with 2% isopropanol. More lutein was desorbed as the amount of adsorbed lutein increased. Desorption from acid ash was greater than that from alkaline ash, which may be due to the absence of potassium from acid ash. The data suggest that the adsorption sites, occupied by lutein, are not all equally accessible to isopropanol, probably because of the irregular structure of the ash.     

Study of the acid character of some palladium-modified pillared clay catalysts: Use of isopropanol decomposition as test reaction

Preparation, textural and structural characterizations as well as acid properties of some aluminium, zirconium pillared montmorillonite (from Algerian bentonite) and including alumina or zirconium pillared montmorillonite supported palladium are reported. Heat resistant basal spacings of 1.7 nm, surface areas in the range of 250–300 m²/g and micropore volumes of about 0.1 cm³/g were obtained. The acid activation of montmorillonite prior pillaring conduces to a resulting material with significantly higher pore volume and acidity. The improvement in acidity is mainly of the Brønsted acid type. The modification of zirconium-pillared montmorillonite with sulfate ions affects the structural properties of the pillared sample but gives a material with strong acid properties and both Lewis and Brønsted acid types are enhanced. It is reported also that textural and structural properties are not affected by the impregnation of a metallic function (1 wt.% Pd loading) but the acid properties changed. The pillared montmorillonite supported palladium has more Brønsted acidity than does the pillared montmorillonite. Decomposition of isopropanol was studied on these systems at low reaction temperature.     

Water-Gas Shift Reaction in a Microchannel Ni-based Catalytic Coated Reactor: Effect of Solvents

Medium-temperature shift (MTS) reaction was investigated in a microchannel reactor using the electrophoretic deposition (EPD) method to coat porous layers of Ni-K/CeO₂ catalyst on stainless-steel plates. The electrolyte suspensions of the catalyst were prepared in isopropanol, ethanol, methanol, and acetone as solvents. All EPD experiments were carried out under similar conditions (i.e., for a contact time of 3 min, at a voltage of 140 V, and in the presence of 0.3 wt % polyethylenimine as the dispersant). The effect of the different solvents on the coated catalytic layers was studied using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and 2D and 3D optical imaging. The experimental results proved that the best performance for the MTS reaction in the plate microreactor was achieved with isopropanol as the solvent.     

渗透汽化回收制药废液中异丙醇

通过渗透汽化脱水浓缩试验降低回收异丙醇的水分量以使回收异丙醇套用于生产。采用HPDA真空渗透汽化膜进行回收异丙醇脱水浓缩生产试验,渗透汽化膜处理后的异丙醇含水量降到0.5%以下,并且没有引入新杂质,结果表明渗透汽化处理后的异丙醇含水量符合生产要求,套用于生产不影响产品质量。     

Zeolite filled P84 co-polyimide membranes for dehydration of isopropanol through pervaporation process

We have developed zeolite 5A and 13X embedded P84 co-polyimide membranes with enhanced permeability and selectivity for the pervaporation dehydration of isopropanol (IPA). It is found that a higher annealing temperature, i.e., is more favorable to improve adhesion between zeolite and polymer phase, and to enhance charge transfer complexes (CTCs) formation. FESEM, DSC and gas permeation results show that zeolite 13X has better compatibility with the matrix polymer than zeolite 5A because of stronger interactions between Na cations in zeolite 13X framework and electron acceptor groups of P84 polyimide. The addition of zeolite into the P84 dense membrane improves water sorption capacity and pervaporation separation performance significantly. Owing to the bigger pore size, larger pore volume, higher sorption capacity and better adhesion, the zeolite 13X incorporated P84 membranes has a much higher permeability than zeolite 5A filled membranes. Interestingly, both have comparably high selectivity possibly because of the effects of chain rigidification and partial pore blockage. The addition of zeolite 13X reduces activation energy for water permeation through the membrane but increases that for IPA permeation. However, the addition of zeolite 5A increases activation energy for both water and IPA permeation. Pervaporation permeability increases with zeolite 13X loading, while the selectivity achieves the maximum at 30 wt% zeolite 13X loading. When the zeolite 13X loading approaches 40 wt%, the adhesion between zeolite and polymer becomes poor and the membrane selectivity declines. A comparison between pervaporation and gas separation results reveals that pervaporation membranes can tolerate a higher degree of interstitial defects than gas separation membranes because of stronger molecular interactions between the feed and the polymer, and the larger molecular size difference between penetrants in the former.     

Effect of the redox treatment of Pt/TiO2 system on its photocatalytic behaviour in the gas phase selective photooxidation of propan-2-ol

Several titania systems were synthesized by the sol–gel method using two different titanium precursors (titanium isopropoxide or tetrachloride) and diverse ageing methods (magnetic stirring, sonication, reflux and microwave radiation). Screening of such different synthetic conditions led us to choose titanium isopropoxide as the titanium precursor and sonication as the method of choice for ageing the gel. Application of the method to the synthesis of a platinum-doped system resulted in a solid with a BET surface area of 57 m²/g and consisting of 100% anatase titania. The system was submitted to different oxidative and reductive treatments in order to study the effect of such treatments on catalytic performance in gas-phase selective photooxidation of propan-2-ol. Interestingly, both oxidation and reduction at 850 °C led to an increase in molar conversion and selectivity to acetone as compared to calcination at 500 °C. So much so, that oxidation at 850 °C either in synthetic air flow or in static air resulted in better catalytic performance than Degussa P25, despite the fact that our catalysts consisted in very low surface area (6–8 m²/g) rutile titania specimens. XPS analyses of the systems showed that thermal treatment at 850 °C resulted in electron transfer from titania to Pt⁰ particles through the so-called strong metal-support interaction (SMSI) effect. Furthermore, the greater the SMSI effect, the better the catalytic performance. Improvement in photocatalytic activity is explained in terms of avoidance of electron–hole recombination through the electron transfer from titania to platinum particles.