氮磷复合肥投加量对厌氧生物制氢发酵类型的影响

采用连续流厌氧产氢发酵反应器研究了氮磷复合肥对厌氧生物制氢产酸发酵类型的影响。试验过程中有机负荷保持不变(21.8 kgCOD/m3.d),复合氮磷肥投加量从高到低先后为40、20、10和0 mg/L进行变化,试验开始20 d后反应器的发酵类型就从原先的丁酸型转变为乙醇型,在此期间气体的总产量变化不大,但氢气含量和产量明显上升。结果表明,营养元素是厌氧发酵法生物制氢反应器运行过程中影响产酸发酵类型的重要因素,投加氮磷复合肥达到10 mg/L就足以影响发酵类型稳定性,高于10 mg/L时易于形成丁酸型发酵,低于10 mg/L时易于形成乙醇型发酵;营养物质的投加量对于系统的pH和ORP值没有明显影响;在生物制氢反应器中,尽管特定微生物群落是形成特殊产酸发酵类型如丁酸型或乙醇型的前提条件,但其它生态因子如营养元素等对于发酵类型的最终形成也具有重要的影响。     

Optimization of detecting hydrogenase activity for acidogenic fermentation of activated sludge

In order to evaluate the hydrogen-producing efficiency of anaerobic activated sludge in Anaerobic Baffled Reactor(ABR)fermentation processes,the optimal conditions for hydrogen producing hydrogenase method on methyl viologen(MV)assay was used to detect the hydrogen production activity of the activated sludge.The most favorable parameters such as 0.6 mL sodium acetate buffer(pH 5.0),100 μL lysozyme,0.2 mL sodium dibromoethane(9.0 mmol/L)and 0.7 mmol/L iron added into 1 mL activated sludge(2.66～26.64 gMLVSS/L)were found.Furthermore,reaction temperature and culture time were detected as 40 ℃ and 30 min respectively.Sodium thiosulfate and sodium sulfides were taken as the reducing agent while trichloroacetic acid as terminator.Under the MV optimal conditions,micro-toxic Dimethyl sulfoxide(DMSO)get higher security and better accuracy.The sensitivity of the detection methods(DMSO as electron carrier)was increased by more than 30%.The results show that the optimal conditions can be applied to measure hydrogenase activity correlating with its specific hydrogen production rate in a hydrogen-producing anaerobic activated sludge system.     

Increase Hydrogen Production by Hydrogen-producing Mutant UV-d48 in Comparison with Wild Parent Strain Etanoligenens sp ZGX4

Hydrogen production by hydrogen-producing mutant strain UV-d48 was one typical ethanol-type fermentative H2-producing mutant, which the main metabolic end production was ethanol and acetic acid. Compare to the wild type strain, the activity of hydrogenase of mutant UV-d48 was stronger in course of growth and fermentation. It can evolve hydrogen at stronger ability and a greater rate than that of its parent wild type, namely ZGX4. Resting cells of UVd48 and Ethanoligenens sp ZGX4 were set up in a batch mode in phosphate buffered saline (PBS) to decouple growth from hydrogen production at the expense of glucose of varying composition. Mutant UV-d48 evolved more hydrogen than ZGX4at glucose concentrations ranging from 2 mmol/L to 200 mmol/L. The difference in the amount of H2 evolved by both strains decreased as the concentration of glucose increased. The maximal H2 yield and H2-producing rate by strain UV-d48 was 3091.1 mL/L and 54 mL/(hODunitL) respectively, at a glucose concentration of 60 mmol/L. With strain ZGX4, the maximal H2 yield and H2-producing rate was 2 180.2 mL/L and 33 mL/(hODunitL) under these conditions, respectively.Experiments using wastewater with certain content molasses yielded similar results. In each case, strain UV-d48 evolved hydrogen at a faster rate than the wild type, showing a possible potential for commercial hydrogen production.     

膨化薯干酒精浓醪发酵

在我国南方薯类原料是最广泛的用于酒精发酵的淀粉质原料.报道了薯干原料经挤压膨化后作为补料进行酒精浓醪发酵的新工艺.经250 mL和3 L三角瓶试验,得到初始料水比为1∶4,预培养10 h后补料,补加膨化料量为初始投料量的60%的较佳工艺.30 L发酵罐进行放大实验结果表明,补料后发酵48 h发酵成熟醪中酒精体积分数达到138 mL*L-1,淀粉利用率可达94.78%,比传统工艺有了大幅度提高.如果能解决工程放大中可能存在的问题,该工艺将有望在工业化生产中得到应用.     

产氢产乙酸菌株AX2的生长条件及产乙酸特性

产氢产乙酸菌群在参与厌氧消化过程的各类微生物菌群中起着承上启下的作用,然而,目前产氢产乙酸菌的纯培养物很少,对其生理生态习性的了解也十分有限.为增加产氢产乙酸菌资源,了解其生理生化特性,通过丙酸和丁酸混合培养基,从厌氧活性污泥中筛选到一株具有产氢产乙酸特性的葡萄球菌(Staphylococcus)AX2,对其生长条件及转化丙酸和丁酸为乙酸的能力进行研究.结果表明,菌株AX2在丁酸培养基(2.4 g/L)和丙酸培养基(2.31 g/L)中的乙酸产量可分别达到278 mg/L和222 mg/L,并在以氯化铵为无机氮源、pH为7.0、35℃等条件下具有最佳的增殖能力.菌株AX2对丙酸、丁酸有较强的乙酸转化能力.     

Effect of Cu2+ concentration on hydrogen fermentation by mixed culture

The results of the study on the effect of Cu2+ concentration on hydrogen production using a glucose solution and mixed microorganisms from a 9.2 L laboratory-scale digester operated at 35 ℃ indicated the productions of hydrogen, volatile fatty acids (VFAs), ethanol and biogas were inhibited by the added Cu2 + which caused a reduction in the glucose degradation efficiency. The specific yields of hydrogen, ethanol and acetate decreased with increased Cu2+ concentration in the mixed microorganisms. When the Cu2 + concentration in the mixed microorganisms was almost an constant, the specific yields of hydrogen, ethanol and acetate were very similar. A 50% inhibition of hydrogen yield (ECso) occurred at a Cu2+ dosage of 0. 50 mg/L in the present investigation. Cu2+ in the external environment is accumulated in the mixed microorganisms. The Cu2 + speciation, using a sequential extraction technique, showed that the Cu2+ was present mainly bound to organic sites in the mixed microorganisms in the present investigation.     

液相法光催化氧化丙烯制环氧丙烷工艺条件的优化

采用正交实验方法考察了液相法光催化氧化丙烯合成环氧丙烷中诸可控因素——乙醇与水体积比、氧气流速和单位体积催化剂用量对环氧丙烷液相浓度和选择性的影响，并对其工艺条件进行了优化。实验结果表明：对于液相环氧丙烷含量，因素乙醇与水体积比作用高度显著，因素氧气流速显著；对于环氧丙烷的选择性只有氧气流速作用显著；单位体积催化剂用量对环氧丙烷液相浓度和选择性影响不显著；最佳工艺条件为乙醇与水体积比2：1，氧气体积流量22．5mL／min和单位体积催化剂质量浓度2．0g／L，此条件下20W紫外灯照射3h得环氧丙烷液相浓度0．0293mol／L，而选择性和收率分别为72．70％和57．52％。     

Mutagenesis and selection of high efficiency hydrogenproducing mutants by ultraviolet radiation

Energy sources are extremely important for theworld to survive, develop and prosper. At present, fos-sil fuels are the major global energy resource but theycause environmental problems during combustion, suchas global warming and acid rain, which have started toaffect the earth’s climate, weather condition, vegeta-tion and aquatic ecosystems, as well as creating serioushealth issues[1 -3]. Considering the energy security andthe global environment, there is a pressing need to ex-ploit new non-…     

pH对发酵系统的产甲烷活性抑制及产氢强化

为抑制厌氧发酵系统的产甲烷活性,强化其发酵产氢性能,采用逐级降低pH的调控方法,探讨连续流搅拌槽式反应器(CSTR)从具有显著甲烷发酵特征的厌氧发酵系统向发酵产氢系统转变的运行特征．在进水COD 7 000 mg／L、水力停留时间(HRT) 8 h条件下,发酵体系在pH 由65～72降低到60～65时,虽然发酵气中的甲烷体积分数逐渐减少乃至消失,但氢气体积分数一直在3％以下;当pH下降到40～50时,系统中的产酸发酵作用得到了进一步强化,挥发性发酵产物总量平均为2 052 mg／L,呈现为典型的乙醇型发酵,发酵气产量平均为26 L／d,其氢气体积分数稳定在45％左右,活性污泥的比产氢率达167 L／(g·d)．     

污泥厌氧发酵物强化低碳氮比生活污水脱氮除磷

为降低使用污泥厌氧发酵物作碳源时的成本,以及简化使用步骤,研究将既不进行发酵液与污泥的分离,也不去除副产物氮和磷的污泥发酵物直接作生活污水脱氮除磷碳源的可行性.以实际低碳氮比城市生活污水为处理对象,将不同量的污泥碱性发酵物(0,20,50,100,200 mL,对应的SCOD质量依次为0,79,198,396,792 mg)作为生物反硝化脱氮和厌氧释磷的碳源,考察脱氮和释磷情况.结果表明:随着投加量的增加,反应结束时氮氧化合物(NO~-_x-N)先降低后升高,当投加量为50 mL(SCOD质量为198 mg、氮质量为12.9 mg、碳氮比为15.3)时,NO~-_x-N质量浓度最低,仅为1.2 mg/L且全部以NO~-_2-N的形式存在,对应的反硝化效率为94.9%;厌氧释磷过程随着污泥发酵物投加量的增多,释磷量不仅没有升高,反而会降低,当投加量为20 mL(SCOD质量为79 mg、氮质量为5.2 mg、磷质量为1.6 mg、碳氮比为15.3、碳磷比为49.5)时,反应结束时释磷量最多,高达23.8 mg/L.此外,通过模拟硝化过程、反硝化过程以及鉴定细胞形态,得出污泥发酵物中硝化细菌和反硝化细菌的细胞结构遭到破坏,其活性均被抑制,即发酵物的引入不影响污水脱氮除磷系统主要菌群结构的稳定性.因此,污泥厌氧发酵物直接做生活污水脱氮除磷的碳源是可行的,本研究中对于反硝化脱氮,50 mL为最佳投加量,对于厌氧释磷,20 mL为最佳投加量.     

钙镁离子对云南磷矿浮选的影响及回水处理

以云南晋宁、安宁和昆阳磷矿为研究对象,在浮选过程中添加钙镁离子,通过回收率、品位的变化研究其对浮选效果的影响.试验结果表明,当加入的钙镁离子达到一定浓度后,对晋宁和安宁磷矿正浮选有不同程度的影响,而对昆阳磷矿单一反浮选影响不大.同时,晋宁和安宁磷矿正浮选尾矿水钙镁离子的测定结果表明,正浮选尾矿水中的钙镁离子浓度为45 mg/L时不足以影响正浮选过程,正浮选尾矿水可直接返回正浮选;当正反浮选废水混合回用,钙镁离子离子浓度超过100 mg/L时,需处理去除.     

不同预处理方法对剩余污泥厌氧发酵产氢的影响

对种泥进行预处理,能去除不产芽孢的耗氢菌,可以达到加快有机废水发酵生物制氢系统启动进程,提高污泥产氢效能的目的.为寻求适宜的种泥预处理方法,利用摇瓶发酵实验,考察城市污水处理厂好氧活性污泥分别经酸、碱、热、曝气、CHCl3和二溴乙烷磺酸钠（BES）预处理后,其利用葡萄糖发酵产氢的特性.结果表明,在初始pH 7.0、葡萄...     

Hydrogen producting characteristics by a novel strain of bacteria-ethanoligenens sp. B49

The objective of this work is to investigate the fermentation capacity and metabolic characteristics of a novel strain of bacteria B49 isolated from anaerobic activated sludge. The examination was conducted in batch culture at 35 ℃. The results showed that the carbon flow gave priority to the production of ethanol, and yield of ethanol is always greater than that of acetic acid. The hydrogen and ethanol occurred simultaneously. The exponential phase of the B49＇ s cell growth was from 12 to 22 h. Evolution of hydrogen appeared to start after the exponential phase of cell growth and reach maximum production at the early stationary phase. The rate of hydrogen production reached a maximum of 16. 8 mL/h, and the percentage of hydrogen gas in the headspace of serum bottle obtained a maximum of 41% at 22 h. The B49 was able to grow using molasses as substrate for cell growth. When the molasses was used as substrate, maximum yield of hydrogen was obtained 2460 mL/L culture at 2 % （V/V） of molasses. The hydrogen yield was increased to 3060 mL/L culture after addition of 0. 5 g/L of yeast extract in the molasses medium and the yield of hydrogen was increased by 24. 4%.     

搅拌桨对菊芋联合生物加工发酵生产燃料乙醇的影响

利用马克斯克鲁维酵母,通过联合生物加工(CBP)技术发酵菊芋生料生成乙醇.在相同的发酵工艺条件下,分别考察四种搅拌桨对乙醇发酵的影响,包括发酵液的混合情况及乙醇浓度、醪液的黏度等参数的变化.结果表明:三叶推进式搅拌桨能够明显提高乙醇产量,并减少发酵液静止区的体积,拆除挡板更适合高浓度菊芋生料的发酵.发酵初始干粉浓度为201 g/L,补料后菊芋干粉终浓度达到273 g/L时,48 h乙醇浓度达到78.11 g/L,乙醇对糖的得率为0.440 7,为理论值的86.25%.此工艺为菊芋乙醇工业化的生产提供了有利条件.     

不同外碳源对污泥反硝化特性的影响

为了选择最优的反硝化外投碳源,应用SBR和A/O反应器,系统地研究了甲醇、乙醇和乙酸钠作为外碳源时污泥的反硝化特性.甲醇、乙醇和乙酸钠作为外碳源时污泥的比反硝化速率分别为3.2 mg/g·h~(-1)、9.6 mg/g·h~(-1)和12 mg/g·h~(-1).甲醇和乙醇作为外碳源时污泥产率大致相同(约为0.40 g/g),而乙酸钠作为外碳源其污泥产率最高(0.65 g/g),甲醇作为外碳源时系统启动时间和驯化期长,不能迅速地响应进水水质的变化.乙醇是反硝化处理系统的最优外加碳源,具有反硝化速率高、污泥产率低、响应迅速、来源广且对环境的影响小等优点.     

污泥发酵液为碳源的反硝化过程亚硝酸盐积累

以污泥发酵液为碳源,通过批次试验研究了不同溶解性有机物的质量浓度与硝酸盐氮质量浓度之比(ρ(SCOD)/ρ(NO-3-N))和分次投加碳源时反硝化过程亚硝酸盐的积累特性.试验结果表明:不同ρ(SCOD)/ρ(NO-3-N)条件下NO-2-N都得到积累;ρ(SCOD)/ρ(NO-3-N)<4时,NO-2-N的最大积累质量浓度和积累速率随着ρ(SCOD)/ρ(NO-3-N)的增加而增大,分别达12.83 mg/L和0.107 mg/(L·min).分次投加发酵液与1次投加发酵液相比,NO-2-N的最大积累质量浓度相差很小,但分次投加能保持稳定的NO-2-N积累.另外,以污泥发酵液为碳源的反硝化过程,反硝化过程NO-2-N的积累和发酵液的低pH导致N2O的释放与ρ(SCOD)/ρ(NO-3-N)成正相关.因此,在构建反硝化耦合厌氧氨氧化系统时,分次投加发酵液具有很大优势,不仅可产生稳定的NO-2-N积累,弱化有机物对厌氧氨氧化菌的抑制作用,还可减少N2O的释放.     

Extraction of electrons by magnetite and ferrihydrite from hydrogen-producing Clostridium bifermentans by strengthening the acetate production pathway

Conductive mineral nanoparticles, such as magnetite, can promote interspecies electron transfer between syntrophic partners.However, the effect of magnetite has only been inferred in intraspecific electron output. Herein, a hydrogen-producing strain,namely, Clostridium bifermentans, which holds several electron output pathways, was used to study the effect of magnetite on the intraspecific electron output manner. Additionally, insulated amorphous ferrihydrite, which was used as an extracellular electron acceptor, was selected to compare with magnetite. Electrons, which were originally used to generate hydrogen, were shunted with the addition of magnetite and ferrihydrite, which resulted in the reduction of hydrogen production and accumulation of Fe(II). Interestingly, more electrons(39.7% and 53.5%) were extracted by magnetite and ferrihydrite, respectively, which led to less production of butyrate and more acetate. More importantly, the increased electron extraction efficiency suggested that electroactive microorganisms can switch metabolic pathways to adapt to electron budget pressure in intraspecific systems. This work broadens the understanding of the interaction between iron oxides and fermentative hydrogen-producing microbes that hold the capacity of Fe(III) reduction.     

一种沥青路面用融雪抗凝冰材料的制备

以Al₂O₃为载体,醋酸盐为抗凝冰活性物质,制备一种道路沥青路面用融雪抗凝冰材料。考察了醋酸钙和醋酸镁的物质的量比对制备材料冰点的影响、三种载体的吸附效果和疏水剂加入量对醋酸盐析出量的影响,同时对抗凝冰融雪效果进行考察。利用红外光谱和热重分析对制备材料的结构及稳定性进行表征。结果表明,融雪抗凝冰材料中醋酸钙和醋酸镁的物质的量比为1∶2,选用自制Al₂O₃载体,有机硅疏水剂的质量分数为9%时,融雪抗凝冰材料高温稳定性较好,具有较好的抑冰融雪效果。     

微波辅助类芬顿技术处理合成类制药废水

研究了微波辅助类酚顿技术处理合成类制药废水的优势,通过优化实验发现,微波辅助类芬顿技术具有催化剂和过氧化氢用量低(硝酸铜0.8 g/L,过氧化氢15 m L/L)、初始反应体系无需酸化、反应时间短(6 min)、污染物去除效果满意(TOC去除率62.64%)、可生化性改善良好(从0.25升至0.37)、处理后Cu2+离子残余质量浓度低(0.625 5 mg/L)等独特优势.在相同条件下该技术采用铜系催化剂比相同物质的量的铁系催化剂的TOC去除效率更理想,即从51.40%提高到62.64%.     

高初糖谷氨酸发酵中接种量与生物素量的研究

为了减少流加糖的损失和进一步提高单位发酵容积内的投糖量,对高初糖谷氨酸发酵工艺进行了研究.通过提高种子液的湿菌体量、发酵罐溶氧效率以及生物素最佳用量,可降低高初糖浓度的抑制作用,显著提高单罐谷氨酸产量.在六半圆叶圆盘涡轮搅拌器的发酵罐中,采用20%湿菌体量的种子液接入200 g/L初糖发酵培养基进行发酵,产酸水平和糖酸转化率分别为142.6 g/L和63.10%,与10%湿菌体量的120 g/L初糖发酵相比,糖酸转化率水平基本接近,单罐谷氨酸产量提高了17.26%.