Extractive acetone-butanol-ethanol fermentation using methylated crude palm oil as extractant in batch culture of Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564)

The possibility of employing methylated crude palm oil (CPOE) as an extraction solvent to reduce end-product inhibition and to enhance solvent productivity in acetone-butanol-ethanol (ABE) fermentation was evaluated using oleyl alcohol as the standard butanol extractant. Fermentation was carried out at an initial glucose concentration of 90 g/l. CPOE did not inhibit the growth of the fermentative organism. Without solvent extraction, butanol production ceased after 30 h at a concentration of 15.4 g/l limiting cell growth to 3.98 g/l and glucose consumption to 62%. Applying CPOE as the extraction solvent, about 47% of the total butanol produced was extracted, glucose consumption was increased to 83% and relatively high glucose consumption rates and solvent productivities were obtained. Butanol production increased to 20.9 g/l; total ABE solvents and yield also increased from 21.2 g/l and 38% (in conventional fermentation) to 29.8 g/l and 40.4%, respectively.     

Novel high-efficient butanol production from butyrate by non-growing Clostridium saccharoperbutylacetonicum N1-4 (ATCC 13564) with methyl viologen

Non-growing Clostridium saccharoperbutylacetonicum N1-4 hardly produced butanol from only butyrate. As adding glucose to the medium, butyrate utilization and butanol production were stimulated. Addition of 0.1 mM methyl viologen as electron carrier resulted in the highest yield of butanol of 0.671 mol/mol to butyrate and glucose.     

High butanol production by Clostridium saccharoperbutylacetonicum N1-4 in fed-batch culture with pH-Stat continuous butyric acid and glucose feeding method

A pH-stat fed-batch culture by feeding butyric acid and glucose has been studied in an acetone-butanol-ethanol (ABE) fermentation using Clostridium saccharoperbutylacetonicum N1-4. The specific butanol production rate increased from 0.10 g-butanol/g-cells/h with no feeding of butyric acid to 0.42 g-butanol/g-cells/h with 5.0 g/l butyric acid. The pH value in broth decreases with butyric acid production during acidogenesis, and then butyric acid reutilization and butanol production result in a pH increase during solventogensis. The pH-stat fed-batch culture was performed to maintain a constant pH and butyric acid concentration in the culture broth, but feeding only butyric acid could not support butyric acid utilization and butanol production. Subsequently, when a mixture of butyric acid and glucose was fed, butyric acid was utilized and butanol was produced. To investigate the effect of the feeding ratio of butyric acid to glucose (B/G ratio), several B/G ratio solutions were fed. The maximum butanol production was 16 g/l and the residual glucose concentration in broth was very low at a B/G ratio of 1.4. Moreover, yields of butanol in relation to cell mass and glucose utilization were 54% and 72% higher in pH-stat fed-batch culture with butyric acid than that of conventional batch culture, respectively.     

重寄生菌粉红粘帚霉SS-1-1菌株的发酵条件优化

采用正交试验和单因素试验对粉红粘帚霉(Gliocladium roseum)SS-1-1菌株发酵条件的优化进行了研究.SS-1-1菌株最佳发酵培养基配方为:麸皮40g/L,玉米粉50g/L,豆饼粉20g/L,KH2PO40.5g/L:最佳发酵条件为:培养基初始pH值为4.5,发酵温度为28℃,摇床转速为200r/min,最佳培养时间为5d.     

分枝杆菌Mycobacterium ZLP生产雄烯二酮(4-AD)的发酵研究

从摇瓶水平上对降解植物甾醇生产雄烯二酮(4-AD)的分枝杆菌的发酵条件进行研究,确定发酵培养基的最适碳源、氮源、无机盐,然后用正交方法对发酵培养基进行优化,结果为:葡萄糖2.0%,蛋白胨2.0%,MgSO4 0.7%,K2HPO4 0.8%,在此基础上确定最佳培养条件:温度28℃,起始pH 7,转化时间96 h,此时4-AD的产率为62.15%.     

Reduction of N2O and NO generation in anaerobic-aerobic (low dissolved oxygen) biological wastewater treatment process by using sludge alkaline fermentation liquid

This paper reported an efficient method to significantly reduce nitrous oxide (N(2)O) and nitric oxide (NO) generation in anaerobic-aerobic (low dissolved oxygen) processes. It was found that by the use of waste-activated sludge alkaline fermentation liquid as the synthetic wastewater-carbon source, compared with the commonly used carbon source in the literature (e.g., acetic acid), the generation of N(2)O and NO was reduced by 68.7% and 50.0%, respectively, but the removal efficiencies of total phosphorus (TP) and total nitrogen (TN) were improved. Both N(2)O and NO were produced in the low dissolved oxygen (DO) stage, and the use of sludge fermentation liquid greatly reduced their generation from the denitrification. The presences of Cu(2+) and propionic acid in fermentation liquid were observed to play an important role in the reduction of N(2)O and NO generation. The analysis of the activities of denitrifying enzymes suggested that sludge fermentation liquid caused the significant decrease of both nitrite reductase activity to NO reductase activity ratio and NO reductase activity to N(2)O reductase activity ratio, which resulted in the lower generation of NO and N(2)O. Fluorescence in situ hybridization analysis indicated that the number of glycogen accumulating bacteria, which was reported to be relevant to nitrous oxide generation, in sludge fermentation liquid reactor was much lower than that in acetic acid reactor. The quantitative detection of the nosZ gene, encoding nitrous oxide reductase, showed that the use of fermentation liquid increased the number of bacteria capable of reducing N(2)O to N(2). The feasibility of using sludge fermentation liquid to reduce NO and N(2)O generation in an anaerobic-low DO process was finally confirmed for a municipal wastewater.     

Improved bioproduction of short-chain fatty acids (SCFAs) from excess sludge under alkaline conditions

The production of short-chain fatty acids (SCFAs) from excess sludge was conducted in batch fermentation tests at different pH values ranging from 4.0 to 11.0. Experimental results of the impacts of different pHs on SCFAs production showed that during the first 8-day fermentation time the total SCFAs production at either pH 9.0 or pH 10.0 was much greater than that at acidic or neutral pH, and the maximal yield of 256.2 mg SCFAs-COD per gram of volatile suspended solids (VSS) was at pH 10.0, which was, respectively, over3 and 4times that at pH 5.0 and uncontrolled pH. Clearly, SCFAs production from excess sludge could be significantly improved and maintained stable by controlling the fermentation pH at 10.0. The composition of SCFAs and the percent distribution of individual SCFAs accounting for total SCFAs at pH 10.0 were analyzed. The SCFAs consisted of acetic, propionic, iso-butyric, n-butyric, iso-valeric, and n-valeric acids, and acetic acid was the most prevalent product with a fraction of 40-55%. Because the results of this study were differentfrom those of previous studies of SCFAs production, the mechanism of increased SCFAs production under alkaline conditions was investigated. Results showed that as soluble COD increased, more soluble protein was provided as the substrate for producing SCFAs. In addition, less or even no SCFAs were consumed by methanogens at alkaline pH, so the SCFAs production was therefore remarkably improved. Further investigation revealed thatthe formation of SCFA at pH 10.0 was dominated by biological effects rather than by chemical hydrolysis.     

Preparation of titanium dioxide (TiO2) from sludge produced by titanium tetrachloride (TiCl4) flocculation of wastewater

Sludge disposal is one of the most costly and environmentally problematic challenges of modern wastewater treatment worldwide. In this study, a new process was developed, which has a significant potential for lower cost of waste disposal, protection of the environment and public health, and yield of economically useful byproducts. Titanium oxide (TiO2), which is the most widely used metal oxide, was produced from the wastewater sludge generated by the flocculation of secondary wastewater with titanium tetrachloride (TiCl4). Detailed analyses were conducted to compare TiCl4, ferric chloride (FeCl3), and aluminum sulfate (Al2(SO4)3) flocculation. Removal of organic matter and different molecular sizes by Ti-salt flocculation was similar to that of the most widely used Fe- and Al-salt flocculation. The mean size of Ti-, Fe-, and Al-salt flocs was 47.5, 42.5, and 16.9 microm, respectively. The decantability of the settled flocs by TiCl4 coagulant was similar to that by FeC13 coagulant and much higher than that of Al2(SO4)3. The photocatalyst from wastewater (PFW) produced by TiCl4 flocculation was characterized by X-ray diffraction, BET surface area, scanning electron microscopy/energy dispersive X-ray, transmission electron microscopy, photocatalytic activity, and X-ray photoelectron spectroscopy. The resulting PFW was found to be superior to commercial TiO2 (P-25) in terms photocatalytic activity and surface area. The PFW as also found to be mainly doped with C and P atoms. The atomic percentage of the PFW was TiO(1.42)C(0.44)P(0.14).     

Optimisation of fermentation conditions for mango (Mangifera indica L.) wine production by employing response surface methodology

Response surface methodology (RSM) was employed for the simultaneous analysis of fermentation conditions of temperature, pH and inoculum size on chemical characteristics such as ethanol, glycerol and volatile acidity, produced during mango wine production by Saccharomyces cerevisiae ( var. bayanus ). The experiments were carried out according to the central composite design to establish the optimum conditions for improving the quality of mango wine. The predicted values for optimisation process conditions were in good agreement with experimental data. The results showed that a satisfactory production of ethanol from the mango juice could be achieved reaching up to 10% (v/v), glycerol concentration is increased to 6.94 g L⁻¹ and volatile acidity is minimised to 0.29 g L⁻¹ at optimised fermentation conditions of temperature 22.5 °C, pH 3.8 and inoculum size 11.9%. Verification of the model indicated no difference between predicted and observed values. Sensory evaluation studies shown overall acceptance of mango wine with good quality.     

Regeneration of perchlorate (ClO4-)-loaded anion exchange resins by a novel tetrachloroferrate (FeCl4-) displacement technique

Selective ion exchange is one of the preferred treatment technologies for removing low levels of perchlorate (ClO4-) from contaminated water because of its high efficiency and minimal impact on water quality through the addition or removal of chemicals and nutrients. However, the exceptionally high affinity of ClO4- for type I anion-exchange resins makes regeneration with conventional NaCl brine extremely difficult and costly for practical applications. The present study entails the development of a novel regeneration methodology applicable to highly selective anion-exchange resins. Tetrachloroferrate (FeCl4-) anions, formed in a solution of ferric chloride and hydrochloric acid (e.g., 1 M FeCl3 and 4 M HCl), were found to effectively displace Cl04- anions that were sorbed on the resin. A mass-balance analysis indicated that a nearly 100% recovery of ion-exchange sites was achieved by washing with as little as approximately 5 bed volumes of the regenerant solution in a column flow-through experiment There was no significant deterioration of the resin's performance with respect to ClO4- removal after repeated loading and regeneration cycles. Thus, the new methodology may offer a cost-effective means to regenerate ClO4- -loaded resins with improved regeneration efficiency, recovery, and waste minimization in comparison with conventional brine regeneration techniques.     

meso-四（4-甲氧基-3-磺酸钠基苯基）卟啉测定果醋中铅含量

利用混酸对果醋进行硝化,以meso-四(4-甲氧基-3-磺酸钠基苯基)卟啉为显色剂,分光光度法测定样品中铅含量.实验结果表明:检测上限为11μg/10mL,表观摩尔吸光系数2.11x105L/mol·cm,抗干扰能力强.     

脂肪酶催化拆分1-(4-甲氧基苯基)乙醇的研究

研究筛选了多种脂肪酶对1-(4-甲氧基苯基)乙醇对映体进行酶法催化拆分,表明来自洋葱假单胞茵脂肪酶(PS IM)在催化拆分中表现出了最高的活力和立体选择性,一种来自小麦胚芽的脂肪酶(WGL)在催化的过程中表现出了与其它脂肪酶相反的选择性.研究了有机溶剂体系中温度和水活度对PS IM催化拆分效果的影响,表明35C是最佳温度,水活度0.69为最佳水活度,在此条件下,转化率和对映体选择性分别达到很好的效果(C 50%,eep99%,ees99%).     

甲型H1N1流感解读

2009年3月底墨西哥暴发了"人感染猪流感"疫情,该疫情迅速在全球范围内蔓延,对人类造成了巨大的威胁,引起了世界各国的重视。本文介绍了上世纪以来全球暴发的主要流感疫情,并对此次流感疫情的病原学、流行病学、防控以及治疗措施做了详细介绍。     

5-(4-(2-甲氧二氧)苯烯)-2-硫代噻唑-4-酮对雪莲果中酪氨酸酶的抑制作用

通过分光光度法探究5-(4-(2-甲氧二氧)苯烯)-2-硫代噻唑-4-酮(MBTO)对雪莲果中酪氨酸酶的抑制作用。结果表明：MBTO对雪莲果中酪氨酸酶有良好的抑制作用。单因素试验最佳抑制剂浓度为30.0μmol/L、最佳作用时间为210s、最佳作用温度为30℃。通过三因素三水平正交试验,分析得最佳反应条件为：pH7.5、抑制剂MBTO浓度30.0μmol/L、作用时间330s、作用温度30℃,可达到最佳抑制效果,在此条件下MBTO对雪莲果中酪氨酸酶的抑制率达84.24%。     

Effect of retrogradation,pancreatin digestion and amylose/amylopectin ratio on the fermentation of starch by Clostridium butyricum (NCIMB 7423)

Using three different maize starches (maize, waxy maize and high amylose maize, containing 25%, 1% and 52% amylose, respectively) the influence of amylose/amylopectin content and of retrogradation on fermentation by the porcine caecal anaerobe Clostridium butyricum was assessed. Small intestine digestion was simulated using pancreatin before the starches were exposed to bacterial fermentation. It was found that retrogradation appeared to alter the extent of the fermentation and hence the amount of short-chain fatty acids produced, while pancreatin digestion appeared to alter the way in which the organism fermented the starch and hence the acetate/butyrate ratio. The amylose/amylopectin ratio seemed to have more influence on the way the starch was fermented by the bacteria after the starch had been subjected to digestion with pancreatic enzymes, but had less influence when the starch had been retrograded. © 1998 SCI.     

Antibacterial properties of polypropylene textiles modified by poly(2-(N,N-dimethyloamino ethyl) methacrylate)

Polypropylene nonwoven fabrics samples were modified using poly(2-(N,N-dimethyloamino ethyl) methacrylate) (PDAMA) and silver-containing layers. The structure of the material after modification was confirmed using scanning electron mocroscope, energy-dispersive X-ray spectroscopy, Fourier Transfer Infrared Spectroscopy (FTIR), and electro-kinetic measurements. It was found that samples with external PDAMA layers have excellent activity against Staphylococcus aureus under dynamic contact conditions. In contrast, samples finished with deposited silver showed little antimicrobial effect. Antibacterial tests conducted under static conditions showed no antibacterial activity irrespective of the deposited layers.     

微生物发酵法制备4-羟基-2,5-二甲基-3[2H]-呋喃酮的研究进展

4-羟基-2,5-二甲基-3[2H]-呋喃酮(HDMF)是一种很好的食品调味剂,具有很高的商业价值.文中分析了微生物发酵法制备HDMF的优越性,总结了产生HDMF的菌种,论述了对其产生机理进行的探索,说明了目前存在的问题,并展望了运用现代生物技术手段改良菌种、构建幕因工程菌株、达到高产HDMF的研究前景.     

Oxidation of sulfonamide antimicrobials by ferrate(VI) [Fe(VI)O4(2-)

Sulfonamide antimicrobials are used in both human therapy and animal husbandry. Sulfonamides are not readily biodegradable and have been detected in surface water and in secondary wastewater effluents. The chemical oxidation of sulfonamides by an environmentally friendly oxidant, ferrate(VI) (Fe(VI)O4(2-), Fe(VI)), was conducted. The sulfonamides used in the oxidation studies were sulfisoxazole, sulfamethazine, sulfamethizole, sulfadimethoxine, and sulfamethoxazole. Kinetics of the reactions were determined as a function of pH (7.0-9.7) and temperature (15-45 degrees C) by a stopped-flow technique. The rate law for the oxidation of sulfonamides by Fe(VI) is first-order with respect to each reactant. The observed second-order rate constants decreased nonlinearly with an increase in pH and are possibly related to the protonation of Fe(VI) (HFeO4- <==> H+ + FeO4(2-); pK(a,HFeO4) = 7.23) and sulfonamides (SH <==> H+ + S-; pK(a,SH) = 5.0-7.4). The activation parameters of the reactions vary with pH due to temperature dependence on the protonation of Fe(VI) and sulfonamides. These results were used to obtain enthalpy of dissociation of sulfonamides. Stoichiometry and products of sulfamethoxazole (SMX) reactions with Fe(VI) were studied in detail using various analytical techniques to evaluate the effect of the oxidation process on the fate of sulfonamides in water. At a stoichiometric ratio of 4:1 (Fe(VI): SMX), complete removal of SMX was achieved. Analyses of oxidation products of the reaction as well as kinetic measurements of substructural models of SMX suggest that the attack of Fe(VI) occurs at the isoxazole moiety as well as at the aniline moiety with minimal preference. The results of the studies reported suggest that Fe(VI) has the potential to serve as a chemical oxidant for removing sulfonamides and converting them to relatively less toxic byproducts in water.     

Biotransformation of 3-nitro-4-hydroxybenzene arsonic acid (roxarsone) and release of inorganic arsenic by Clostridium species

The extensive use of 3-nitro-4-hydroxybenzene arsonic acid (roxarsone) in the production of broiler chickens can lead to increased soil arsenic concentration and arsenic contaminated dust. While roxarsone is the dominant arsenic species in fresh litter, inorganic As (V) predominates in composted litter. Microbial activity has been implicated as the cause, but neither the specific processes nor the organisms have been identified. Here we demonstrate the rapid biotransformation of roxarsone under anaerobic conditions by Clostridium species in chicken litter enrichments and a pure culture of a fresh water arsenate respiring species (Clostridium sp. strain OhILAs). The main products were 3-amino-4-hydroxybenzene arsonic acid and inorganic arsenic. Growth experiments and genomic analysis indicate strain OhILAs may use roxarsone as a terminal electron acceptor for anaerobic respiration. Electronic structure analysis suggests that the reducing equivalents should go to the nitro group, while liberation of inorganic arsenic from the intact benzene ring by cleaving the C-As bond is unlikely. Clostridium and Lactobacillus species are common in the chicken cecum and litter. Thus, the organic-rich manure and anaerobic conditions typically associated with composting provide the conditions necessary for the native microbial populations to transform the roxarsone in the litter releasing the more toxic inorganic arsenic.     

氯吡苯脲处理对采后莲蓬保鲜效果的影响

为探索采后莲蓬保鲜新方法,选用‘太空莲36号’为试材,首先以不同质量浓度（2.5、5.0、10.0、15.0、 20.0 mg/L）氯吡苯脲（1-(2-chloropyridin-4-yl)-3-phenylurea,CPPU）对莲蓬进行处理,以莲蓬及莲子感官品质、莲 皮色差、莲子蛋白含量为依据,筛选出最佳的莲蓬处理质量浓度;然后,以不作处理（CK0）和清水浸泡（CK1） 作对照,在（25±1）℃贮藏条件下,研究了CPPU处理对鲜莲蓬呼吸作用及鲜莲子褐变度、可溶性固形物质量分 数和淀粉含量、丙二醛（malondialdehyde,MDA）和过氧化氢（hydrogen peroxide,H2O2）含量、超氧阴离子自 由基（superoxide anion radical,O2 －?）生成速率及超氧化物歧化酶（superoxide dismutase,SOD）、过氧化氢酶 （catalase,CAT）、过氧化物酶（peroxidase,POD）和多酚氧化酶（polyphenol oxidase,PPO）活力的影响。结 果表明：CPPU处理莲蓬的最佳质量浓度为5.0 mg/L,CPPU处理可有效防止莲蓬及莲子褐变,维持莲蓬和莲子较 好的表型,并抑制莲蓬呼吸作用,减少莲子可溶性固形物积累和淀粉消耗,减小O2 －?生成速率和H2O2、MDA等的 累积,同时与对照组相比,能维持较高的SOD、CAT活力,抑制POD、PPO活力。此外,经CPPU处理后,莲子 中CPPU残留量低于国家标准。综上所述,CPPU处理有利于提高采后莲蓬及莲子贮藏品质,是采后鲜莲蓬贮藏保 鲜的一种新方法。