SAM产生菌酿酒酵母HYS98发酵动力学及比生长速率控制策略

通过恒化培养对S-腺苷甲硫氨酸(SAM)产生菌酿酒酵母HYS98发酵动力学进行了研究. 结果表明,该菌株的生长与限制性基质蔗糖浓度之间符合Monod关系式,最大比生长速率μmax为0.28 h-1,饱和常数KS为1.27 g/L;当0.005 h-1≤μ≤0.11 h-1,产物生成模型为qSAM=-1.39μ2+0.19μ,底物消耗动力学模型为qS=μ/0.62+0.012. 基于建立的动力学模型,提出了分阶段控制菌体比生长速率的流加培养策略,据此策略在5 L反应器中发酵24 h,SAM浓度达3.56 g/L,而SAM产率达0.15 g/(L·h),比文献报道的最高水平高67%.     

Performance evaluation of a water/silicone oil two‐phase partitioning bioreactor using Rhodococcus erythropolis T902.1 to remove volatile organic compounds from gaseous effluents

BACKGROUND: In the framework of biological processes used for waste gas treatment, the impact of the inoculum size on the start‐up performance needs to be better evaluated. Moreover, only a few studies have investigated the behaviour of elimination capacity and biomass viability in a two‐phase partitioning bioreactor (TPPB) used for waste gas treatment. Lastly, the impact of ethanol as a co‐substrate remains misunderstood. RESULTS: Firstly, no benefit of inoculation with a high cellular density (>1.5 g L^?1) was observed in terms of start‐up performance. Secondly, the TPPB was monitored for 38 days to characterise its behaviour under several operational conditions. The removal efficiency remained above 63% for an inlet concentration of 7 g isopropylbenzene (IPB) m^?3 and at some time points reached 92% during an intermittent loading phase (10 h day^?1), corresponding to a mean elimination capacity of 4 × 10^?3 g L^?1 min^?1 (240 g m^?3 h^?1) for a mean IPB inlet load of 6.19 × 10^?3 g L^?1 min^?1 (390 g m^?3 h^?1). Under continuous IPB loading, the performance of the TPPB declined, but the period of biomass acclimatisation to this operational condition was shorter than 5 days. The biomass grew to approximately 10 g L^?1 but the cellular viability changed greatly during the experiment, suggesting an endorespiration phenomenon in the bioreactor. It was also shown that simultaneous degradation of IPB and ethanol occurred, suggesting that ethanol improves the biodegradation process without causing oxygen depletion. CONCLUSION: A water/silicone oil TPPB with ethanol as co‐substrate allowed the removal of a high inlet load of IPB during an experiment lasting 38 days. Copyright © 2008 Society of Chemical Industry     

大孔吸附树脂富集款冬花总黄酮的研究

研究了大孔吸附树脂富集款冬花总黄酮的工艺。从5种大孔吸附树脂中筛选出AB-8型大孔吸附树脂适合富集款冬花总黄酮,并通过单因素实验确定适宜的富集工艺为:将4BV的款冬花样品液以3BV·h-1的速度上样,吸附40min,用4BV的纯化水以6BV·h-1的速度冲洗杂质,再用4BV的60%乙醇洗脱总黄酮。该树脂稳定性良好,可连续使用6次。     

Novel kinetic model for the simulation analysis of the butanol productivity of Clostridium acetobutylicum ATCC 824 under different reactor configurations

Acetone–butanol–ethanol(ABE)fermentation process can be exploited for the generation of butanol as biofuel,however it does need to overcome its low volumetric solvent productivity before it can commercially compete with fossil fuel technologies.In this regard,mathematical modelling and simulation analysis are tools that can serve as the base for process engineering development of biological systems.In this work,a novel phenomenological kinetic model of Clostridium acetobutylicum ATCC 824 was considered as a benchmark system to evaluate the behaviour of an ABE fermentation under different process configurations using both free and immobilized cells:single stage batch operation,fed-batch,single stage Continuous Stirred Tank Reactor(CSTR)and multistage CSTRs with and without biomass recirculation.The proposed model achieved a linear correlation index r~2=0.9952 and r~2=0.9710 over experimental data for free and immobilized cells respectively.The predicted maximum butanol concentration and productivity obtained were 13.08 g·L~(-1)and 1.9620 g·L~(-1)·h~(-1)respectively,which represents an increase of 1.01%and 990%versus the currently developed industrial scale process reported currently into the literature.These results provide a reliable platform for the design and optimization of the ABE fermentation system and showcase the adequate predictive nature of the proposed model.     

甲苯对厌氧反应过程的影响研究

研究了甲苯对厌氧反应过程的影响。结果发现,厌氧系统对有机负荷的冲击有一定的缓冲作用,产酸相内挥发性脂肪酸（VFA）浓度随有机负荷的提升而升高;当甲苯浓度≤20mg·L-1时,对产酸相CODc,的降解及VFA的产量具有明显抑制作用,驯化一段时间后可恢复正常;甲苯对产甲烷相和产酸相CODcr去除无明显抑制作用。甲苯浓度≤70mg·L^-1时,甲苯在厌氧系统内可得到良好的降解,出水甲苯浓度〈0．1mg·L^-1,达到国家一级排放标准。即使进水甲苯浓度达到200mg·L^-1,甲苯的去除率仍达99％以上。     

Effects of coagulation-bath conditions on polyphenylsulfone ultrafiltration membranes

Polyphenylsulfone(PPSU)ultrafiltration membrane with different structures was prepared by non-solvent-induced phase separation.The effects of coagulation bath conditions(concentration and temper-ature)on membrane morphology,pure water flux,pore size,porosity,and contact angle were studied and discussed based on ternary-phase diagrams.Results indicated that water had stronger coagulant power than ethanol,and that the morphology of the membrane prepared from the polyphenylsulfone/1-methyl-2-pyrrolidinone/H2O(PPSU/NMP/H2O)system had finger-like structures.Conversely,sponge-like struc-tures were observed for the PPSU/NMP/(NMP-H2O)and PPSU/NMP/(70NMP-EtOH-H2O)systems.Ethanol also greatly influenced on membrane structures.According to the Scanning electronic micro-scopy(SEM)image,the composition(mass fraction)of casting solution is 16％PPSU-84％NMP and the coagulation bath consisting of 70％NMP-26％H2O-4％C2H5OH.Meanwhile,the PPSU ultrafiltration mem-brane with spong-like was prepared under 8℃coagulation bath.The formation of sponge-like structure reduces the pure water flux of ppsu membrane from 488.39 L·m-2·h-1 to 36.04 L m-2·h-1.It also reduces the gas permeability,porosity,and pore size of the membrane.The addition of ethanol and NMP into the coagulation bath increases the roughness of the PPSU ultrafiltration membrane and reduces the hydrophilicity of the membrane.     

Osmotic concentration of succinic acid by forward osmosis: Influence of feed solution pH and evaluation of seawater as draw solution

In this study, we investigated the essential role of feed solution pH so as to gain insights into the transport mechanisms of succinic acid concentration by osmotically-driven forward osmosis(FO) process. FO performances including water flux and bidirectional transport of succinate and chloride anions were systematically examined using cellulose triacetate-based FO membrane. Additionally, real seawater was explored as draw solution. Experimental results revealed that the p H-dependent speciation of succinic acid can affect the FO performances. Ionization of succinic acid at higher solution p H enhanced the osmotic pressure of feed solution, thus leading to lower water flux performance. A strong effect was pointed out on the succinate rejection for which nearly 100% rejections were achieved at p H above its pK_(a2) value. The rejection of succinate increased in the following order of chemical form: C_2H_4 C_2O_4H_2 C_2H_4C_2O_4H~ˉ C_2H_4C_2O_4~(2-).With real seawater as the draw solution, low to moderate water fluxes(4 L·m~(-2)·h~(-1)) were observed.The divalent succinate anion was highly retained in the feed side despite differences in the succinic acid feed concentration at p H of approximately 6.90.     

Characterization and application of a recombinant dopa decarboxylase from Harmonia axyridis for the efficient biosynthesis of dopamine

Here,a dopa decarboxylase (DDC) from Harmonia axyridis was heterogeneously expressed in Escherichia coli for the efficient biosynthesis of dopamine.For the production of recombinant DDC,the cultivation conditions including IPTG concentration,temperature and induction time were optimized and obtained an optimal specific enzyme activity of 51.72 U·mg-1 crude extracts.After the purification of DDC with a recovery yield of 68.79％,its activity was further characterized.The Vmax,Km,Kcat,and Kcat/Km of DDC for dihydroxyphenylalanine (dopa) were 0.02 mmol·ml-1·s-1,2.328 mmol·ml-1,10435.90 s-1 and 4482.77 ml·mmol-1·s-1,respectively.The highest DDC activity was observed at the condition of pH 7.5 and 45 ℃.With the purified DDC,the feasibility to produce dopamine from L-dopa was evaluated.The optimal yield was determined at the following bioconversion conditions:pH of 7.0,the reaction temper-ature of 40 ℃,0.4 mmol·L-1 of PLP and 4 g·L-1 of L-dopa.Subsequently,a fed-batch process for the pro-duction of dopamine was developed and the effect of oxygen was evaluated.The titer,yield and productivity of dopamine reached up to 21.99 g·L-1,80.88％ and 14.66 g·L-1h-1 at 90 min under anaer-obic condition.     

Effect of surfactants and biomass on the gas/liquid mass transfer in an aqueous‐silicone oil two‐phase partitioning bioreactor using Rhodococcus erythropolis T902.1 to remove VOCs from gaseous effluents

BACKGROUND: The two‐phase partitioning bioreactor (TPPB) has become a new strategy for waste gas treatment. However, the impact of biomass and surfactants on gas/liquid (G/L) mass transfer needs to be better evaluated because the effects on the mass transfer coefficient K_L and the interfacial area a, respectively, remains misunderstood. RESULTS: This study showed that, first, the surfactant extract produced by Rhodococcus erythropolis reduced the surface hydrophobicity of the biomass. Secondly, an optimal concentration appeared to exist for both components, respectively 0.5 g L^?1 and 0.7 g L^?1 for biomass (B) and surfactant extract (SE) when the global mass transfer coefficient (K_La) of oxygen was measured in a silicone oil/water TPPB. However, the combination of B and SE was found to induce a negative synergism. In particular, SE improved the interfacial area a by increasing the bubble diameter, while B reduced it as soon as a concentration of 1 g L^?1 was exceeded. In contrast, the SE acted negatively on the K_L, while B improved it overall. CONCLUSION: Better consideration is needed of the effect of biotic components in order to understand the phenomenon of G/L mass transfer in a TPPB. The behaviour of biomass growth and surfactants may strongly influence the mathematical models proposed in the literature. Copyright © 2009 Society of Chemical Industry     

利用肺炎克雷伯氏菌以葡萄糖和磷酸铵盐为底物生产2,3-丁二醇

1 INTRODUCTION Interest in microbial production of 2,3-butanediol has been increasing recently due to the extensive indus-trial application of this product. This colorless and odorless liquid with a high boiling point and a low freezing point is a potential valuable fuel additive. Its heating value is 27.198kJ·g-1, which is quite near the value of ethanol (29.055kJ·g-1). Besides, condensation of diol to methyl ethyl ketone (MEK) coupled with subsequent hydrogenation yields octane isom…     

Simulation study of biobutanol production in a polymer-loaded two-phase partitioning bioreactor (PL-TPPB): Simulation and strategy for biobutanol production

A simulation study was performed for a two-phase partitioning bioreactor (TPPB) with polymer beads, Dowex Optipore L-493, as a second phase. When the initial glucose concentration is less than 30 g/L, a single-phase bioreactor is preferred, because it consumed all the glucose with 40% of biobutanol yield. Any glucose over the concentration remained in the single-phase bioreactor because cells were completely inhibited by products, mainly biobutanol, and thus glucose availability became less than 100%. The TPPB with 10% polymer beads completely consumed up to 120 g/L glucose and more polymer beads were required for the higher glucose concentration. Instead of increasing the proportion of polymer beads, 2 vvm of nitrogen gas was introduced continuously into the TPPB for the stripping of products, reducing product inhibitions. By applying gas stripping to the TPPB containing 10% polymer beads, 150 g/L of glucose was completely consumed and 99.7% acetone, 46.8% butanol and 82.5% ethanol was stripped out of the TPPB. Finally, on the basis of these estimations, a novel strategy based on the initial glucose concentration was suggested for high biobutanol production.     

次毫米过滤组件分区高含量污泥试验研究

采用次毫米过滤(SMF)组件实现高含量污泥(MLSS)分区(A区和B区),为膜生物反应器(B区)的稳定高效运行提供适宜的污泥质量浓度(5.0～10.0 g.L-1)。研究了回流体积比≥2.0条件下SMF组件(孔径0.47 mm)分离高含量污泥的运行特征及分区效果,对比分析了两区微生物实测与理论含量的差异,并考察了SMF组件耦合A区对营养物的去除效果。结果表明,在分离高含量污泥时,目标B区的污泥的质量浓度为2.0～10.0 g.L-1,对膜生物反应器是适用的;对应A区的污泥的质量浓度在15.5～33.5 g.L-1。SMF组件滤出液MLSS的质量浓度在1.4～4.2g.L-1,平均通量可达192 L.m-.2h-1。此外,SMF组件耦合A区对COD的去除率在82%以上。     

生物活性泡沫乳液反应器处理被苯、甲苯、二甲苯污染的空气

A novel bioactive foam emulsion bioreactor for benzene, toluene and xylene (BTX) contaminated air streams treatment has been developed. The gas-liquid interfacial area by biocompatible foam and driving force for mass transfer by a water immiscible organic phase were increased in this reactor. The effect of several parameters such as gas residence time, oxygen content, and organic phase concentration on bioreactor performance was studied. Experimental results showed an average elimination capacity (EC) of 220 g&;#8226;m－3&;#8226;h－1 with removal efficiency (RE) of 89.59% for BTX inlet concentration of 1 g&;#8226;m－3 at 15 s gas residence time in the bioreactor. The statistical developed model predicted that the maximum elimination capacity of the reactor for BTX could be reached to 423.45 g&;#8226;m－3&;#8226;h－1. Continues operation of the bioreactor with high EC and RE was demonstrated by optimizing the operational parameters of the bioreactor. Overall the results suggest that the bioreactor developed can be very effective systems to treat BTX vapors.     

一种复合生物除臭填料的性能评价

本试验采用水泥粘合—挤压造粒法,获得了一种复合废气生物过滤填料,以硫化氢为模拟废气,玉米芯、多孔陶粒为对比填料,对该填料各项性能进行评价。填料的空隙率为88%,堆密度为0.52 kg.m-3,压缩强度为78kPa,比表面积为780 m2.m-3,pH值为7.0;当进气流量为0.2 m3.h-1、进气浓度为0～200 mg.m-3时,硫化氢的去除率在85%以上;并且在处理负荷小于170 g（H2S）/（m3.d）-1时,硫化氢去除率仍维持在85%以上,达到良好的生物除臭效果。试验运行阶段填料的最大干、湿生物量为15.4 kg.m-3和373.8 kg.m-3。     

Study on gas-liquid flow characteristics in stirred tank with dual-impeller based on CFD-PBM coupled model

Study on gas-liquid flow in stirred tank with two combinations of dual-impeller (six-bent-bladed turbine(6BT)+six-inclined-blade down-pumping turbine (6ITD),the six-bent-bladed turbine (6BT)+six-inclined-blade up-pumping turbine (6ITU)) was conducted using computational fluid dynamics (CFD) and popula-tion balance model (PBM) (CFD-PBM) coupled model.The local bubble size was captured by particle image velocimetry (PIV) measurement.The gas holdup,bubble size distribution and gas-liquid interfacial area were explored at different conditions through numerical simulation.The results showed that the 4 mm bubbles accounted for the largest proportion of 33％ at the gas flow rates Q =0.76 m3·h-1 and 22％ at Q =1.52 m3·h-1 for combined impeller of 6BT + 6ITU,while the bubbles of 4.7 mm and 5.5 mm were the largest proportion for 6BT + 6ITD combination,i.e.25％ at Q =0.76 m3·h-1 and 22％ at Q =1.52 m3·h-1,respectively,which indicated that 6BT + 6ITU could reduce bubble size effectively and promote gas dispersion.In addition,the gas holdup around impellers was increased obviously with the speed compared with gas flow rate.So it was concluded that 6ITU impeller could be more conductive to the bubble dispersion with more uniform bubble size,which embodied the advantages of 6BT + 6ITU combination in gas-liquid mixing.     

Biofiltration of toluene in the absence and the presence of ethyl acetate under continuous and intermittent loading

BACKGROUND: Two peat biofilters were used for the removal of toluene from air for one year. One biofilter was fed with pure toluene and the other received 1:1 (by weight) ethyl acetate:toluene mixture. RESULTS: The biofilters were operated under continuous loading: the toluene inlet load (IL) at which 80% removal occurred was 116 g m^?3 h^?1 at 57 s gas residence time. Maximum elimination capacity of 360 g m^?3 h^?1 was obtained at an IL of 745 g m^?3 h^?1. The elimination of toluene was inhibited by the presence of ethyl acetate. Intermittent loading, with pollutants supplied for 16 h/day, 5 days/week, did not significantly affect the removal efficiency (RE). Biomass was fully activated in 2 h after night closures, but 6 h were required to recover RE after weekend closures. Live cell density remained relatively constant over the operational period, while the dead cell fraction increased. Finally, a 15 day starvation period was applied and operation then re‐started. Performance was restored with similar re‐acclimatization period to that after weekend closures, and a reduction in dead cell fraction was observed. CONCLUSION: This study demonstrates the capacity of the system to handle intermittent loading conditions that are common in industrial practices, including long‐term starvation. Copyright © 2008 Society of Chemical Industry     

Static and dynamic studies of adsorption by four macroporous resins to enrich oridonin from Rabdosia rubescens

Oridonin, one of the active ingredients in Rabdosia rubescens(R. rubescens), has been reported to induce cell apoptosis and cell cycle arrest in many cancers. Conventional extraction methods tend to result in unsatisfied enrichment and poor quality of oridonin present in a given biomass. This paper aims to evaluate the performance and separation characteristics of four different macroporous resins to arrive at the most suitable methodology for the isolation and purification of high-quality oridonin. Static absorption kinetics, thermodynamic and dynamic adsorption were evaluated. HP-20 was selected for further study due to its high adsorption capacity of 32 mg·g~(-1) and desorption ratio with 98.5%. The pseudo-secondorder model was considered to be the most suitable for kinetic results, and Langmuir model was chosen to better describe the absorption thermodynamics. Under optimum conditions(flow rate of 4 ml·min~(-1),bed depth with 6 cm and initial concentration of 2.15 mg·min~(-1)), the effective content of oridonin increased from 33.9% to 79.1% in the dry extract with a recovery of 81% and the purity of oridonin improved from 76% to 93%. The results confirm that HP-20 provides an efficient method to purify most oridonin from R. rubescens.     

吡蚜酮在大鼠体内的毒代动力学研究

采用LC-MS/MS分析方法研究不同染毒剂量下吡蚜酮在SD大鼠体内的毒代动力学特征。色谱柱为Phenomenex Luna C18(50mm×4.6mm,5μm),采用ESI离子源,定量离子对为218.30/105.30。结果表明,大鼠经口灌胃给予吡蚜酮后,由统计矩参数表示的低、高两个剂量组(100mg·kg-1、1 000mg·kg-1)主要毒代动力学参数如下:达峰时间(tmax)分别为4h和2h;峰值浓度(cmax)分别为36 180μg·L-1和69 388μg·L-1;消除半衰期(t1/2β)分别为18.972h和33.177h;表观分布容积(Vz)分别为2.65L·kg-1和8.236L·kg-1;体内总清除率(CLz)分别为:0.107L·h-1·kg-1和0.266L·h-1·kg-1;毒时曲线下面积[AUC(0~t)]分别为652 604.71μg·h·L-1和1 674 767.1μg·h·L-1;AUC(0~∞)分别为931 164.77μg·h·L-1和1 876 484.6μg·h·L-1。在毒性剂量下,吡蚜酮在大鼠体内的毒代动力学过程具有非线性动力学特征。值得注意的是,1 000mg·kg-1剂量组消除半衰期较长,易发生蓄积。该分析方法适用于大鼠血浆中吡蚜酮的测定。     

Performance evaluation of the incorporation of different wire meshes in between perforated current collectors and membrane electrodeassembly on the Passive Direct methanol fuel cell

Passive Direct methanol fuel cells (DMFC) are more suitable for charging small capacity electronic devices. In passive DMFC, the fuel and oxidant are supplied by diffusion and natural convection process on the anode and cathode sides respectively. Current collectors (CC) play a vital importance in fuel cell performance. This paper presents the combined impact of perforated and wire mesh current collectors (WMCC) on passive DMFC performance. Three types of open ratios of perforated current collectors (PCC), such as 45.40％, 55.40％and 63.40％and two types of wire mesh current collectors with open ratios of 38.70％and 45.40％were chosen for the experimental work. A combination of Taguchi-L9 rule is con-sidered. A combination of three PCC and two WMCC on both anode and cathode was used. Methanol con-centration was varied from 1 mol·L-1–5 mol·L-1 for nine combinations of PCC and WMCC. From the experimental results, it is noticed that the combination of PCC and WMCC with an open ratio of 55.40％ and 38.70％ incorporated passive DMFC produced peak power density at 5 mol·L-1 of methanol concentration. The passive DMFC performance was evaluated in terms of maximum power density and maximum current density. The combined current collectors of PCC and WMCC open ratios of 55.40％+38.70％ have more stable voltage than single PCC of open ratio 63.40％ at 4 mol·L-1 of methanol concentration.     

DOT-200重整油脱烯烃催化剂的研制与工业应用

为了解决芳烃工业面临的白土固废压力,并进一步降低现有脱烯烃技术的催化剂再生工作强度,采用改性超稳化Y型分子筛HUSY-2制备了DOT-200重整油脱烯烃催化剂(DOT-200催化剂),并用X射线衍射、NH3程序升温脱附、扫描电镜/透射电镜以及氮气物理吸附等方法进行表征,分别在实验室和工业装置上考察了DOT-200催化剂的反应行为和性能。结果表明:DOT-200催化剂强酸中心量较少,二次孔结构更丰富,比表面积和孔容、孔径较大。单程寿命是DOT-100催化剂的1.5倍,二者再生效果相当,在150℃条件下基本无导致二甲苯损失和甲苯增加的副反应。在原料平均溴指数800 mg-Br/100g左右、质量空速1.7~1.8 h~(-1)的情况下,可在工业装置上连续运行9个月,甲苯增量0.10%~0.14%,二甲苯无明显损失,吸附进料溴指数始终低于20 mg-Br/100 g。DOT-200催化剂综合性能良好。