Effect of initial substrate and biomass concentrations on anaerobic fermentative hydrogen production in batch reactors

The effects of initial substrate (5 -60 g/L) and biomass concentration (0.5 -3 g/L) on fermentative hydrogen production by mixed cultures were investigated in batch tests using glucose as substrate.The...     

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.     

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...     

外循环气升式生物反应器中酯酶生产及应用

采用海藻酸钙凝胶包埋法固定根霉（Rhizopus sp. F-16）细胞,在外循环气升式生物反应器（工作体积为10 L,高径比为2.9）中发酵生产酯酶.与游离细胞发酵相比,固定化细胞具有发酵时间短、产酶活力高等优点,其最适通气量为0.70 m3/h,最适装液量为8.75 L,发酵48 h时酯酶活力达41.6 U/g细胞.固定化细胞的适宜作用pH为8.0～9.0,适宜作用温度为45～50 ℃,其酸碱稳定性和热稳定性均比游离细胞明显增强.该固定化细胞可直接用于选择性水解外消旋乳酸乙酯生成D-乳酸,当底物的质量浓度为150 g/L,反应时间为3 h时乳酸乙酯的水解率达43.9%,D-乳酸的光学纯度达95.7%.固定化细胞性状稳定,可重复利用,连续降解6批乳酸乙酯的平均水解率为43.3%,D-乳酸的光学纯度平均为95.4%.     

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)．     

氧化亚铁硫杆菌的固定化及其对Fe2+的氧化研究

以沸石为填料、气液逆流形式的固定化细胞装置填料塔,操作条件控制为空气量0.5 m3/h、循环液体流量1.0 L/h,在培养基的初始pH =2.0、Fe2+初始浓度为8g/L左右的条件下,氧化亚铁硫杆茵固定化细胞只需10h就达95％以上Fe2+的氧化率,其Fe2+平均氧化速率高达0.88 g/(L.h),固定化细胞Fe2+平均氧化速率是游离细胞的11倍.固定化细胞经长期低pH值驯化后,仍能保持较高的Fe2+氧化活性,在初始pH=1.6的条件下,只需14h Fe2+氧化率就达95.18％,Fe2+平均氧化速率达0.63 g/(L.h);是驯化前Fe2+平均氧化速率的1.58倍.     

利用含葡萄糖废水光催化制氢

研究了葡萄糖为电子给体在Pt/TiO2上光催化生成氢的反应.葡萄糖明显提高了制氢反应效率,反应5 h内,反应生成氢的量与反应时间成线性关系;葡萄糖初始浓度对生成氢反应速率的影响符合Langmu ir关系式;考察了无机离子对光催化反应的影响;用循环伏安法对光催化反应进行监测,发现降解过程中生成了葡萄糖酸.讨论了可能的反应机理.     

接种物预处理对泔脚发酵产氢的强化研究

采用经微波（850W,4min）＋pH9．0预处理的泔脚为发酵底物,以预处理的城市生活垃圾厌氧消化污泥为接种物,考察了接种物的未预处理、热（80℃,15min）预处理、热（80℃,15min）＋pH6．0预处理对泔脚中温（36℃）批式发酵产氢的影响．（1）Gompertz模型拟合结果表明：3个预处理方案的泔脚发酵产氢延迟时间λ分别为7．68、5．06、2．04h,泔脚中挥发性固体最大比产氢率分别为3．05、10．10、9．24mL／g·h,泔脚中挥发性固体产氢率分别为43．54、167．10、161．93mL／g,生物气中氢气的最高体积含量分别为18．4％、41．2％、47．2％．结合药剂的费用,热（80℃,15min）预处理具有更大的产氢优越性．（2）泔脚的发酵产氢过程也是一个酸化过程,发酵产氢结束后,3个预处理方案的发酵产氢余物的pH值在4．70～5．10,pH值均有较大幅度的下降．     

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.     

高效生物滴滤塔处理硫化氢臭气的试验研究

针对生物脱臭处理工艺存在的问题,在实验室用化学方法产生H2S气体,利用筛选、驯化的高效除臭菌形成的固定化生物滤料进行连续脱臭试验.结果表明:当H2S进气量在0.05~0.5 m3/h,进气质量浓度在300~700 mg/m3时,反应器对H2S的去除率均在98%以上.反应器运行时pH值的下降并不影响H2S的去除效果.反应器启动快并能够保证足够的反应时间,具有较高的除臭效率.     

两种类型生物制氢反应器的运行及产氢特性

为探求反应器型式对发酵法生物制氢过程的影响,分别采用连续流搅拌槽式反应器(CSTR)和颗粒污泥膨胀床反应器(EGSB)接种厌氧活性污泥,从糖蜜废水中制取氢气.运行中控制温度为35℃,通过缩短水力停留时间(HRT)和增加进水COD质量浓度的方式逐渐提高容积负荷(OLR),分别对CSTR系统和EGSB系统的产氢速率、pH、液相末端产物及生物量进行研究.结果表明,两个系统中,产氢速率均随OLR提高而逐渐升高.CSTR的最佳产氢OLR为25~35 kg/(m3.d),而EGSB的最佳产氢OLR为70~80 kg/(m3.d);此时,CSTR系统的最大产氢速率为6.21 L/(L.h),EGSB系统的最大产氢速率可达18.0 L/(L.h).稳定运行期,EGSB系统的生物量为27.6 gVSS/L,而CSTR的生物量仅为7.8 gVSS/L,说明较高的生物量是生物制氢反应器稳定运行和高效产氢的关键.两个系统均可形成乙醇型发酵,说明发酵类型的形成不受反应器型式影响.与CSTR反应器相比,EGSB反应器具有更好的耐酸能力.     

New amperometric glucose biosensor by entrapping glucose oxidase into chitosan/nanoporous ZrO2/multiwalled carbon nanotubes nanocomposite film

A new nanocomposite material for construction of glucose biosensor was prepared. The biosensor was formed by entrapping glucose oxidase(Gox) into chitosan/nanoporous ZrO2/multiwalled carbon nanotubes nanocomposite film. In this biosensing thin film, the multiwalled carbon nanotubes can effectively catalyze hydrogen peroxide and nanoporous ZrO2 can enhance the stability of the immobilized enzyme. The resulting biosensor provides a very effective matrix for the immobilization of glucose oxidase and exhibits a wide linear response range from 8 μmol/L to 3 mmol/L with a correlation coefficient of 0.994 for the detection of glucose. And the response time and detection limit of the biosensor are determined to be 6 s and 3.5 μmol/L, respectively. Another attractive characteristic is that the biosensor is inexpensive, stable and reliable.     

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-…     

用于高效产氢的多功能Co-B 催化剂

通过简易的溶液沉淀法,一步制备了几种纳米级钴硼(Co-B)催化剂, Co-B化合物可用作多功能催化剂,主要用于水解NaBH4和电解水制氢。研究发现Co-B的催化活性与制备工艺密切相关。以四氢呋喃(THF)为溶剂制备的Co-B化合物,当Co、B原子比为1.8时, Co-B化合物展现了较高的催化活性,催化NaBH_4水解产氢速率可达7.45 L/(min·g)。此外,在100 A/m~2的电流密度下, Co-B化合物可催化电水解,其析氢反应和析氧反应的过电位分别为270 mV和310 mV。     

一株分离自潮间带污泥细菌Clostridium sp. T7产氢特性分析

产氢菌株Clostridium sp. T7分离自天津海水浴场潮间带的污泥.研究起始pH、碳源、氮源、NaCl质量分数对菌株T7产氢性质的影响.结果表明：菌株T7最适产氢的起始pH是6.0,能够利用蔗糖、葡萄糖和果糖等碳源发酵产氢.菌株T7能够利用牛肉膏和酵母粉为单一氮源产氢,不能利用蛋白胨为氮源进行产氢.NaCl质量分数能影响菌株T7的产氢量,海水培养条件（NaCl质量分数为3%）下,最高产氢量是每摩尔葡萄糖（1.48,±0.05）mol,相比之下,淡水培养条件下其产氢量提高20%.NaCl质量分数在0.4%～7%时,菌株T7都能够产氢,这表明菌株T7有望应用于淡水或高盐有机废水产氢领域.     

CdS纳米线的溶剂热合成及其光催化产氢性能

采用乙二胺溶剂热法制备了CdS纳米线(NWs), 探究了乙二胺用量及晶化条件对CdS NWs的组成、结构、形貌、比表面积、光吸收性能、电化学性能和光解水产氢性能的影响. 结果表明, 优化条件下制得的CdS NWs长径比可达550、径向直径约50 nm且分散良好. 在可见光驱动的光催化分解水产氢实验中, CdS NWs的产氢速率可达316 μmol·g-1·h-1, 与不加乙二胺的硫化镉相比提高了3.0倍. 在产氢循环实验中, 反应进行到第四个循环时的产氢速率约为初始值的81%, 具有良好的稳定性, 这为一维CdS NWs在光催化分解水制氢中的进一步改性提供了基础.     

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。     

秸秆糖化复合菌系的筛选方法及糖化效果评价

为了获得能够直接降解秸秆积累还原糖的复合菌系,并评价其产糖能力,采用连续稀释转接的方法进行复合菌系的富集筛选.同时,提出利用分室同步糖化发酵产氢培养的方法,将降解秸秆复合菌系与高效产氢菌株分室培养,以产氢所消耗还原糖量,推算复合菌系的产糖能力,以此作为评价复合菌系糖化效果的方法.实验结果表明:利用连续稀释转接法,筛选得到糖化效果较好的复合菌系JY665,菌体产氢量与所消耗还原糖量可拟合为二次曲线,通过计算得到复合菌系产糖能力达到0.5150g/g秸秆,秸秆降解率达到61.06%.     

蜡状芽孢杆菌的筛选及其产氢性能

为了研究纯菌种对产氢的影响,从污水厂活性污泥中分离了纯的产氢菌种XN12,根据16S rDNA序列和DnaJ基因序列、细胞形态、生理生化数据等多项鉴定分析,该菌种被鉴定为蜡状芽孢杆菌(Bacillus cereus).为了研究该纯菌的产氢性能,实验以葡萄糖为底物,在不同pH值条件下观察其产气情况.实验结果表明:以每摩尔葡萄糖计,该菌在中性条件下获得最大产氢量为1.6 mol.对反应的液相产物的检验结果表明:该菌为丁酸发酵菌,通过丙酮酸代谢途径产出氢气.     

Magnesium improves hydrogen production by a novel fermentative hydrogen-producing bacterial strain B49

Hydrogenisaclean, effectiveandrenewableen ergy, andisanultimatereplacementforfossilhydro carbonfuelsinthefuture. Biohydrogenfromwasteisattractiveduetosimultaneousenergyrecoveryandenvi ronmentalcleanup. Biohydrogengenerationbyphoto andnon photosyntheticbacteriahasbeenstudiedexten sively[1 4]. Ingeneral, metalionsforenzymeshavetwofunctions. Oneistoserveasacofactor, whichisresponsiblefortransferringelectron, atomandfunction algroups; theotherisasanactivatortoimproveactivi tyofenzymes. Therea…