细菌发酵生产酒精之工业应用前景探索

本研究对细菌和酵母这两类不同菌株,在发酵酒精的性能方面作了多方面的比较。实验结果表明:玉米淀粉水解液及糖蜜可用于运动发酵单胞细菌发酵生产酒精,但糖蜜需经活性灾吸附,脱除有害物质。酒糟水和玉米浆可替代酵母膏,良好地用作为细菌发酵酒精的氮源。细菌具有较强的抗染菌能力。细菌经吸附固定化后,发酵速度比游离菌快,也比固定化酵母快。因此,运动发酵单胞细菌生产酒精,有着良好的工业应用前景,在不久的将来,将会代替酵母,而成为酒精工业中的重要菌株。     

纤维素直接发酵乙醇微生物的选育──Ⅱ.运动发酵单胞原生质体的形成与再生最佳条件的研究

运动发酵单胞（ZymomonasmobillisATCC29191）在不同的条件下产生的菌体其形成原生体所需的条件亦不同，而且原生质体的再生亦有差异．经过最佳化的条件选择，原生质体的再生率最高可达79.03×10-2水平。     

Mathematical modelling of the alcoholic fermentation of glucose by Zymomonas mobilis mobilis

The kinetics of alcoholic fermentation of a strain of Zymomonas mobilis, isolated from sugarcane juice, has been studied with the objective of determining the constansts of a non-structured mathematical model that represents the fermentation process. Assays in batch and in continuous culture have been carried out with different initial concentrations of glucose. The final concentrations of glucose, ethanol and biomass were determined. The following kinetic parameters were obtained: μ_max, 0·5 h^?1; K_s, 4·64 g dm^?3; P_max, 106 g dm^?3; Y_x/s, 0·0265 g g^?1; m, 1·4 g g^?1 h^?1; α, 17·38 g g^?1; β, 0·69 g g^?1 h^?1.     

五碳糖和六碳糖共发酵生产酒精菌株选育的研究进展

利用纤维质原料发酵生产燃料酒精是目前研究的热点。综述了五碳糖和六碳糖共发酵生产酒精菌株选育的研究进展。主要介绍了利用自然微生物、重组运动发酵单胞菌（Zymomonas mobilis）、重组大肠杆菌（Escherichia coli）和重组酿酒酵母（Saccharomyces cerevisiae） 酒精发酵的进展情况。指出定向进化或改变多个相关基因群,使细胞整体满足木糖的代谢需求,以及对重组菌进行随机突变、进化选育并结合现代高通量筛选等技术是未来研究工作的重点。     

纤维素直接发酵乙醇微生物的选育──Ⅲ.里氏木霉与运动发酵单胞原生质体融合的研究

用聚乙二醇（PEG）作为诱导剂，可使钝化的里氏木霉（Tri－chodermareesei）QM9414的原生质体和运动发酵单胞（Zymomonasmobilis）ATCC29191的原生质球之间可以产生远缘的细胞融合子。融合率可达1．9×10－2融合子能利用羧甲基纤维素为唯一碳源而产生羧甲基纤维素酶和乙醇。羧甲基纤维素酶活性高和乙醇产量高的融合子不稳定。这些融合子的产酶能力很容易大部分丧失，而产乙醇的能力亦很低。而酶活及乙醇产量较低的融合子，可能才是真正的基因重组子。     

木糖发酵菌种研究进展

综述了已发现的发酵木糖的天然微生物种类、木糖代谢途径及其机理以及近年来构建基因工程菌发酵木糖生产乙醇的研究进展.重点介绍了酿酒酵母、运动发酵单胞菌以及大肠杆菌的基因改造情况.     

Analytical effectiveness factor calculations concerning product-inhibited fermentations associated with biofilm growth and maintenance

An analytical reaction engineering model, recently presented by van Ede et al. (1992), which describes formation of inhibiting products associated with the growth of immobilized biofilms, is extended to describe simultaneous production associated with biofilm maintenance. The model accounts for both the metabolic rate controlling behaviour of an inhibitory product in the biofilm, and the effect of diffusion limitation in the transport of this product or a substrate, on the biofilm thickness. Simple criteria are presented to check the applicability of the model in the case of true Monod kinetics. As a potentially industrially important example, ethanol production by Zymomonas mobilis is treated.     

Fermentative production of biofuels with entrapped anaerobic sludge using sequential HRT shifting operation in continuous cultures

In this work, a continuously stirred tank bioreactor (CSTBR) was used to produce gaseous (hydrogen) and liquid (ethanol) biofuels simultaneously from carbohydrate substrates using immobilized anaerobic sludge with polyethylene–octene–elastomer (POE) matrix. The continuous culture was operated by sequential decrease and increase of hydraulic retention time (HRT) to assess the effect of HRT shifting on the efficiency of H₂ and ethanol production. The experimental results show that during HRT-decreasing operation, using sucrose as the carbon substrate resulted in increasing H₂ and ethanol production with an increase in organic loading rate or a decrease in HRT. The best biofuel-producing performance occurred during HRT decrease, giving the highest H₂ production rate and yield of 37.4 mmol/h/L and 1.18 mol H₂/(mol(hexose)), respectively (at 4 h HRT), as well as a maximal ethanol production of 84.1 mmol/h/L and 0.9 mol ethanol/(mol(hexose)) (at 0.5 h HRT). For continuous cultures fed with glucose-based medium, the biofuel production rate and yield was lower than those from using sucrose, and the dependence of biofuels production on HRT shifting had a slightly different trend. Ethanol production with glucose-feeding cultures seemed to be optimal during a HRT increase (HRT = 1 h), but H₂ production reached maximum during a decreasing HRT (HRT = 1 h). For all the continuous cultures, ethanol was the predominant soluble metabolite, accounting for 35–78% of total soluble microbial products, while production of acetate and butyrate was less significant. Calculation of total energy generation resulting from combination of the two biofuels shows that the best energy generation rate (116 kJ/h/L) and yield (1235 kJ/(mol(hexose))) was obtained during HRT decreasing (HRT = 0.5 h) while using sucrose was the carbon substrate.     

Sago starch saccharification and simultaneous ethanol fermentation by amyloglucosidase and Zymomonas mobilis

Simultaneous saccharification and ethanol fermentation (SSF) of sago starch was studied using amyloglucosidase (AMG) and Zymomonas mobilis. The optimal concentration of AMG and operating temperature for the SSF process were found to be 0.5% (v/w) and 35°C, respectively. Under these conditions with 150 g dm^?3 sago starch as a substrate, the final ethanol concentration obtained was 69.2 g dm^?3 and ethanol yield, Y_P/S, 0.50 g g^?1 (97% of theoretical yield). Sago starch in the concentration range of 100–200 g dm^?3 was efficiently converted into ethanol. When compared to a two-step process involving separate saccharification and fermentation stages, the SSF reduced the total process time by half.     

para‐Substituted 2‐Phenyl‐3,4‐dihydroquinazolin‐4‐ones As Potent and Selective Tankyrase Inhibitors

Human tankyrases are attractive drug targets, especially for the treatment of cancer. We identified a set of highly potent tankyrase inhibitors based on a 2‐phenyl‐3,4‐dihydroquinazolin‐4‐one scaffold. Substitutions at the para position of the scaffold′s phenyl group were evaluated as a strategy to increase potency and improve selectivity. The best compounds displayed single‐digit nanomolar potencies, and profiling against several human diphtheria‐toxin‐like ADP‐ribosyltransferases revealed that a subset of these compounds are highly selective tankyrase inhibitors. The compounds also effectively inhibit Wnt signaling in HEK293 cells. The binding mode of all inhibitors was studied by protein X‐ray crystallography. This allowed us to establish a structural basis for the development of highly potent and selective tankyrase inhibitors based on the 2‐phenyl‐3,4‐dihydroquinazolin‐4‐one scaffold and outline a rational approach to the modification of other inhibitor scaffolds that bind to the nicotinamide site of the catalytic domain.     

Synthesis of proton conductive membranes based on inorganic–organic hybrid structure bound with phosphonic acid

Proton conductive inorganic–organic hybrid membranes were synthesized from styrene derivatives of alkoxysilane and ethyl 2-[3-(dihydroxyphosphonyl)-2-oxopropyl] acrylate (EPA) through copolymerization followed by sol–gel reaction. Self-standing, homogeneous and transparent hybrid membranes with chemically bound phosphonic acid groups were synthesized. FT-IR analysis exhibited the hybrid membranes included phosphonic acid groups. ¹³C and ²⁹Si NMR studies indicated that alkoxysilyl functionalized styrene derivatives were not only copolymerized with EPA but also condensed yielding Si–O–Si linkages by sol–gel reaction. TG–DTA analysis revealed that these membranes were thermally stable up to 200 °C in dry O₂. The proton conductivities of the hybrid membranes increased with phosphonic acid content and temperature. The P/Si ratio of the membrane was dependent on the number of alkoxy group in the starting alkoxysilane. The hybrid membrane from (dimethylmethoxysilylmethyl)styrene (DMMSMS(M))/EPA = 1/6 revealed proton conductivities of 6.3 × 10⁻³ and 2.4 × 10⁻⁴ S cm⁻¹ at 68.0% relative humidity and 18.8% relative humidity, respectively, at 140 °C.     

Selective oxidation of ethane: Developing an orthorhombic phase in Mo–V–X (X = Nb, Sb, Te) mixed oxides

Mo–V–X (X = Nb, Sb and/or Te) mixed oxides have been prepared by hydrothermal synthesis and heat-treated in N₂ at 450 °C or 600 °C for 2 h. The calcination temperature and the presence or absence of Nb determines the nature of crystalline phases in the catalyst. Nb-containing catalysts heat-treated at 450 °C are mostly amorphous solids, while Nb-free catalysts heat-treated at 450 °C and samples treated at 600 °C clearly contain crystalline phases. TPR-H₂ experiments show higher H₂-consumption on catalysts with amorphous phases. Catalytic results in the oxidative dehydrogenation of ethane indicate that the selective production of the olefin is strongly related to the development of the orthorhombic Te₂M₂₀O₅₇ or (SbO)₂M₂₀O₅₆ (M = Mo, V, Nb) phase (the so-called M1 phase), which is mainly formed at 600 °C. This active and selective crystalline phase is characterized to show moderate reducibility and active centers enough for the selective oxidative activation of ethane with the minimum quantity possible of active centers for ethylene activation. In this sense, the best yield to ethylene has been achieved on a Mo–V–Te–Nb mixed oxide.