Partitioning and purification of extracellular β-1,3-1,4-glucanase in aqueous two-phase systems

The partition behaviors of β-1,3-1,4-glucanase, α-amylase and neutral proteases from clarified and whole fermentation broths of Bacillus subtilis ZJF-1A5 were investigated. An aqueous two-phase system （polyethylene glycol （PEG）/MgSO4） was examined with regard to the effects of PEG molecular weight （MW） and concentration, MgSO4 concentration, pH and NaC1 concentration on enzyme partition and extraction. The MW and concentration of PEG were found to have significant effects on enzyme partition and extraction with low MW PEG showing the greatest benefit in the partition and extraction of β-glucanase with the PEG/MgSO4 system. MgSO4 concentration influenced the partition and extraction of β-glucanase significantly, pH had little effect on β-glucanase or proteases partition but affected a-amylase partition when pH was over 7.0. The addition of NaCl had little effect on the partition behavior of β-glucanase but had very significant effects on the partitioning of α-amylase and on the neutral proteases. The partition behaviors of β-glucanase, α-amylase and proteases in whole broth were also investigated and results were similar to those obtained with clarified fermentation broth. A two-step process for purifying β-glucanase was developed, which achieved β-glucanase recovery of 65.3% and specific activity of 14027 U/mg, 6.6 times improvement over the whole broth.

Measurement and Correlation of Partition Coefficients of Baicalin in EOPO/Salt Aqueous Two-Phase Systems

The partition coefficients of baicalin were measured in ethylene oxide and propylene oxide (EOPO)/salt aqueous two-phase systems at 298.15K. It was found that most of baicalin partitioned into EOPO-rich phase. The partition coefficients of baicalin varied from 10 to 120. The effect of various factors, including tie-line length, salt composition, molecular weight of EOPO, and solution pH, on the partition behavior was investigated in EOPO/salt systems. Furthermore the partition coefficients of baicalin were correlated using the modified Diamond-Hsu model. Good agreement with experimental data is obtained. The average relative deviations are less than 5.0%.

Effects of Hydrophobicity of Ethylene Oxide-Propylene Oxide Copolymers on Phase Diagrams of Aqueous Two-Phase Systems and Partition Behaviors of Cephalexin and 7-Aminodeacetoxicephalos-poranic Acid

A series of ethylene oxide (EO)-propylene oxide (PO) randomco-polymers (EOPO) were used to form aqueous two-phase systems (ATPS)with ammonium sulfate. Effects of EOPO's properties on the phaseseparation behaviors and on the partition of cephalexin and7-aminodesacetoxicephalosporanic acid (7-ADCA) in ATPS wereinvestigated. Both the molar mass and molar ratio of EO to PO of EOPOcould greatly influence partition behaviors of cephalexin and 7-ADCAas well as the binodal curve of ATPS.

Efficient Separation of Butyric Acid by an Aqueous Two-phase System with Calcium Chloride

One of the bottlenecks for bioproduction of butyric acid as bulk chemical is the difficulty in separating butyric acid from the fermentation broth,compared with the petroleum-based chemical synthesis method.In the present work,a novel separation methodology was developed based on an aqueous two-phase system with inor-ganic salts.Calcium chloride was screened out for effective separation of butyric acid from butyric acid-water-salt systems.Within appropriate concentration range of butyric acid and salt,butyric acid was enriched in the upper phase and most of calcium ions remained in the lower phase.This"salting out"effect is very efficient to separate butyric acid from the simulated butyrate fermentation broth,which consists of butyric acid and acetic acid with concentration ratio of 4︰1,so that the final ratio of butyric acid/acetic acid in the upper phase is improved to 9.87. The aqueous two-phase system was used to separate butyric acid from the actual fermentation broth with satisfac-tory result.

Preparation of Iminodiacetic Acid-Polyethylene Glycol for Immobilized Metal Ion Affinity Partitioning

The synthesis route was investigated and optimized for the preparation of iminodiacetic acid-polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phase systems. IDA-PEG was synthesized from PEG in two steps by the reaction of iminodiacetic acid with a monosubstituted derivative of epichlorohydrin-activated PEG. The Cu2+ content combined with IDA-PEG was determined by atomic absorption spectrometry as 0.5 mol·mol^-1 (PEG). Furthermore, the affinity partitioning behavior of lactate dehydrogenase in polyethylene glycol/hydroxypropyl starch aqueous two-phase systems was studied to clarify the affinity effect of the Cu(Ⅱ)-IDA-PEG.

Partitioning of biomaterials in aqueous two-phase systems of mixed cationic-anionic surfactants

In a previous paper, we have showed that, when aqueous solutions of cationicand anionic surfactants at certain concentrations were mixed, the solution separatedspontaneously into two immiscible phases (aqueous two-phases), one phase was rich,and the other was poor in the mixed surfactants. A clear interfacial boundary existsbetween two phases.

两相分配生物反应器处理有机废气新技术

综述了近期国内外有关两相分配生物反应器处理有机废气技术的研究进展。介绍了搅拌釜生物反应器、生物滴滤塔、生物滤床等多种反应器结构及其去除有机废气的效果;分析了硅油、十六烷、十四烷等多种非水相介质在两相分配生物反应器中应用的优缺点;阐述了有机废气在两相分配生物反应器中的传质机理。最后对两相分配生物反应器的发展前景及改进方向进行了分析。

壬基酚聚氧乙烯醚在MBR与CASR中的行为

对比研究了壬基酚聚氧乙烯醚（NPnEO,n为1-4）在膜-生物反应器（MBR）和传统活性污泥反应器（CASR）中的去除效果和迁移行为.结果表明,在相同NPnEO污泥负荷的条件下,采用不主动排泥的运行模式,2种反应器均能有效去除NPnEO,去除率分别为99.2%和97.1%,MBR的去除效果更稳定.前21d中,2种反应器中混合液NPnEO浓度均呈现先增大后减小的趋势,但MBR出水NPnEO浓度小于其混合液浓度,而CASR出水浓度则高于其混合液浓度;21d后,2种反应器混合液与出水浓度均趋于一致.活性污泥对NPnEO具有吸附作用,但对去除NPnEO的贡献很小;推测生物降解是去除NPnEO的主导作用.

两相分配(有机相—水相)生物反应器降解污染物的原理及应用

有毒有机污染物大多为人工合成的异生物合成物,具"三致"与生物难降解等特性,对环境和人类健康造成了严重的威胁。本文论述了两相分配生物反应器对有毒有机污染物的降解原理及其应用现状。该反应器基于热力学平衡原理,通过引入有机相,消除有机污染物对微生物的抑制作用,在快速降解污染物的同时实现体系的自控。现有研究表明,可高效降解苯、苯酚、BTX、多环芳烃等有毒有机污染物。此外,对该反应器的进一步研究与应用进行了展望。

两相分配生物反应器中苍白杆菌PW对芘的降解效果

为降低PAHs对微生物的毒性,促进PAHs的降解,采用TPPB技术（two-phase patitioning bioreactor,两相分配生物反应器）对芘进行降解,研究了不同有机相（硅油、十二烷、十一醇、癸烷、十六烷、十八烷）、ρ（芘）、φ（有机相）和扰动速率对芘降解的影响.结果表明：当φ（有机相）为10.0%、ρ（芘）为100～1 000 mg/L时,T0（纯水相）及T1（水-硅油）、T2（水-癸烷）、T3（水-十二烷）、T4（水-十一醇）、T5（水-十六烷）和T6（水-十八烷）体系中芘的降解率分别为92.5%～13.9%、69.3%～20.1%、79.6%～23.3%、81.9%～26.9%、86.7%～28.1%、87.7%～34.1%、89.6%～27.4%.ρ（芘）较低时,TPPB抑制了芘的降解;ρ（芘）较高时,TPPB则能促进芘的降解.6种有机相中,十六烷对芘降解的促进效果最优.最优φ（有机相）的确定和ρ（芘）有关,ρ（芘）为200 mg/L时,最优φ（十八烷）、φ（十六烷）、φ（十一醇）分别为5.0%、2.5%和5.0%;ρ（芘）为1 000 mg/L时,其均为20.0%.液体扰动速率的提高能促进芘的降解,液体扰动速率为50～200 r/min时,T6和T5体系中的芘的降解率分别为50.1%～75.6%和54.1%～79.1%.研究显示,TPPB技术是一种潜在治理高浓度PAHs污染的有效途径,TPPB的优化是多种影响因素综合作用的结果.

两相分配生物反应器降解苯乙烯废气的研究

为提高生物法净化难溶性VOCs的效率,构建以硅油(体积分数为10%)为非水相的两相分配生物反应器(Two Phase Partitioning Bioreactor,TPPB)。通过响应面优化试验,探讨TPPB最佳工艺条件,研究进气质量浓度、循环液pH值、停留时间及液气比对苯乙烯废气净化效果的影响,并对比其与单相生物反应器(One Liquid Phase Bioreactor,OLPB)处理效果的差异。结果表明,进气质量浓度为400 mg/m^(3)、停留时间为45.77 s、循环液pH值为7.26、液气比为0.25的最佳工艺参数下,TPPB的苯乙烯去除率达96.15%。基于数学模型拟合两种反应器的传质和生物降解过程,过程模拟发现同一停留时间下TPPB中最大传质分数均高于OLPB;苯乙烯去除负荷变化与Michaelis-Menten模型相关性较高(R^(2)=98.2%),同一停留时间下TPPB的最大去除负荷和半饱和常数均高于OLPB。

甾醇侧链切除的微生物转化技术

甾体化合物是医药工业中具有巨大市场的产品之一,甾醇侧链切除的微生物转化是解决甾体医药原料的基础,像甾醇这一类疏水性底物的微生物转化技术是产业化的关键。本文综述了甾醇侧链切除微生物转化技术的新进展,详细介绍了我们最近开发的浊点系统两相分配生物反应器新技术。

两相分配生物反应器——浊点系统在生物转化中的应用

利用两相分配生物反应器可以控制底物由非水相向水相释放,增加底物的溶解度和解除底物对微生物的抑制,保护产物降解,降低下游分离费用;论述了两相分配生物反应器的基本原理和发展概况,并以胆固醇边链切除生物转化为例,介绍了新开发的浊点系统两相分配生物反应器的巨大潜力。

两相分配生物反应器治理有机废气研究进展

通过研究国内外关于两相分配生物反应器治理有机废气进展,介绍了搅拌釜生物反应器、生物滴滤塔等多种两相分配生物反应器的结构及其工作原理;分析了硅油、十六烷等不同非水相对于不同目标污染物的去除效果;研究了两相分配生物反应器对有机废气的处理性能;最后指出如何消除液态非水相的泡沫化和反应器的堵塞问题是今后研究的关键。

Separation/Extraction/Detection of Chloramphenicol Using Binary Small Molecule Alcohol-Salt Aqueous Two-phase System Coupled with High-performance Liquid Chromatography

A green and sensitive sample separation and purification method coupled with high-perfomiance liquid chromatography(HPLC)was developed for the analysis of chioramphenicol(CAP).One element small molecule alcohol-salt aqueous two-phase system(ATPS)can't effectively adjust the polarity of the system,but binary small molecule alcohol-salt ATPS can adjust the polarity and improve the extraction efficiency of antibiotics.A binary aqueous two-phase system based on 1-propanol+2-propanol and NaH2PO4 system was formed and applied to the separation and purification of trace CAP in real samples.The influence factors on partition behaviors of CAP were discussed,including the types and mass of salts,the volume ratio of alcohol,the pH,temperature and the standing time.The optimal condition was found at pH=5.0,2.5 g of NaH2PO4,3.0 mL of 1-propanol and 2-propanol(volume ratio 1:1)and 30℃by using response surface methodology.Under this optimal condition,the extraction efficiency of CAP reached 98.91%,and partition coefficient of CAP was 17.31.

Phase Behavior of Ionic Liquids-Cesium Carbonate-Water Aqueous Two-phase Systems and Their Extraction of L-Tryptophan

Phase behavior and extraction ability of aqueous two-phase systems（ATPs） consisting of ionic liquids（ILs）, Cs2CO3 and water were investigated in this paper. Four kinds of ionic liquids, namely, 1-amyl-3-methylimidazolium bromide（[Csmim]Br）, 1-hexyl-3-methylimidazolium bromide（[C6nim]Br）, 1-heptyl-3-methylimidazolium bromide （[C7mim]Br） and 1-octyl-3-methylimidazolium bromide（[C8mim]Br）, were examined to discuss the influence of alkyl groups. Binodal curves and tie-lines at 288.15, 298.15 and 308.15 K were obtained. The partitioning behavior for L-tryptophan in such ATPs was further investigated. The effect of temperature, pH, Cs2CO3 concentration and the structure of ionic liquids on the partitioning were discussed in detail.

木糖氧化无色杆菌P1对芘降解的研究及其在两相分配生物反应系统中的应用

采用富集培养技术筛选芘降解微生物,得到一株纯培养条件下可以有效降解芘的细菌,命名为P1,经鉴定为木糖氧化无色杆菌(Achromobacter xylosoxidans)。研究了培养条件对P1降解的影响,在此基础上考察了其在两相分配生物反应系统中对芘的降解。研究结果表明:菌株P1可以有效降解培养体系中的芘,在芘的初始质量浓度为100 mg/L,p H为7,温度为30℃时,对芘的降解效果最好;在两相分配生物反应系统中菌株P1对芘的降解速率大于单相反应系统,且降解率受到非水相类型和芘初始浓度的影响,其中以十一醇为有机相的双相反应系统较十二烷和硅油更能促进生物降解,5 d内降解率为78.8%。

两相分配式生物反应器处理高盐废水中的苯酚

采用新型两相分配式生物反应器(TPPB)和前期研究得到的高效苯酚降解菌对高盐废水中苯酚的降解进行研究,研究中确定煤油为反应系统的最佳有机溶剂,并考察了废水苯酚含量、废水盐度以及搅拌器搅拌速度对苯酚降解的影响。结果表明,反应系统能正常降解苯酚含量为1 000～2 500 mg/L的高盐苯酚废水;反应系统在含盐量为100 g NaCl/L、搅拌速度为50 r/min的运行工况条件下,降解时间缩短为52 h,总酚去除率为20.58 mg/(L.h)。

两相分配生物反应器治理高浓度有机污染研究进展

高浓度有机污染物难以进行生物降解的主要原因之一是其会对微生物产生较大毒害作用而抑制微生物生长以及降解过程,而两相分配生物反应器(Two-phase partitioning bioreactor,TPPB)可以有效解决污染物毒性的问题,因而在高浓度有机污染治理中具有较大的应用潜力.本文系统介绍了TPPB类型以及各自的工作原理,即TPPB通过非水相的引入可以溶解系统内大部分有机污染物,减少水相中污染物的浓度,降低其对微生物的毒性,并通过微生物的代谢活动实现污染物的降解,随着降解过程的进行污染物在两相间的分配平衡不断被打破,污染物又不断从非水相进入到水相之中,使得微生物的降解过程持续进行.同时分析了反应过程中的各种影响因素,如传质速率、微生物影响等,进而阐述了该技术在水体、土壤、大气污染治理中的应用,最后根据目前的研究进展,对TPPB技术的工程应用前景进行了展望.

两相系统在疏水性有机污染物高效降解菌富集培养中的应用研究进展

环境中疏水性有机污染物(Hydrophobic organic pollutants,HOPs)的浓度日益增加,获取HOPs高效降解功能微生物能有效提高HOPs污染治理效率。近年来,利用两相系统促进HOPs微生物降解转化的研究已取得一定进展。本文重点从两相系统的结构特点及其富集HOPs降解功能微生物的原理、主要影响因素和应用情况等方面进行综述,并在此基础上对两相系统在毒害性HOPs微生物加速降解脱毒中所存在的主要问题及其应用前景进行讨论和展望。