预处理方式对微紫青霉菌吸附Cu2+的影响及其吸附机理

为有效提高青霉菌(Penicillium)对含Cu2+的水溶液中的Cu2+的吸附能力并了解其吸附机制, 研究了8种不同预处理方式对微紫青霉菌(Penicillium janthinellum)菌株GXCR的Cu2+吸附的影响。结果表明, 匀浆化、匀浆+碱化(NaOH) (简称匀浆碱化)、高温(80oC)、匀浆+盐化(NaCl)、匀浆+洗涤剂和匀浆+极化(二甲基亚砜)可显著提高菌体的吸附率, 但是匀浆化+酸化处理会导致菌体的Cu2+吸附能力显著下降。与早期其他研究相比, 本研究发现匀浆化碱化(NaOH)相结合的方式能够显著提高菌体的吸附能力。其中匀浆碱化(NaOH, 0.5 mol/L)处理后菌体的Cu2+的吸附率增加了47.95%; 匀浆碱化菌体吸附符合典型的Langmuir方程, 表明该菌对吸附Cu2+的吸附可能是以表面吸附为主。吸附-解吸循环4次后, 碱化菌体的Cu2+的吸附率仍可达到70.82%。红外光谱分析表明碱化处理主要影响菌体表面分子的-OH、C=O和COOH基团中的C=O, 其中与Cu2+结合的主要基团是-OH。GXCR的对Cu2+的吸附可能是主要基于Cu2+与菌体-OH基团结合的化学吸附为主。     

青霉菌Penicillium janthinellum 菌株 GXCR的高抗重金属盐及其对Cu2+和 Zn2+离子吸收的特性

从广西某矿区污泥中分离了一株高抗Cu2 的真菌,编号为GXCR,根据形态和5.8SrRNA基因的内转录间隔子区的DNA序列同源性将其鉴定为Penicilliumjanthinellum。GXCR能够耐200mmolL–1的Cu2 ,在5mmolL–1Mn2 存在下,可在含800mmolL–1Cu2 的PDA上生长。在PDA培养基上,限制GXCR生长的其它金属盐的最小浓度(mmolL–1)依次为:Zn2 ,>1200;Al3 ,>500;Na ,>250;Mn2 ,>200;Cd2 ,50;Cr3 ,>60;Cr6 ,>3;Ni2 ,20;Pb2 ,50。对Cu2 、Cr6 、Pb2 和Zn2 ,的抗性是pH依赖性的,在pH3~7,随着pH的升高,其抗性急剧下降。在含3种金属盐混合物的PDL(未添加琼脂的PDA)中的GXCR生长的正交实验结果表明:金属盐之间存在显著的毒性协同效应;毒性协同效应强度不仅与盐的种类也与组成盐之间的浓度相关;GXCR有较高的抗3种金属盐混合物的能力。原子吸收测定结果表明:在含20mmolL–1Cu2 去离子水溶液中,未经NaOH预处理的自然菌体的Cu2 吸收量为38.1mgg-1干菌体,经200mmolL–1NaOH预处理的菌体的吸收量为76.9mgg-1干菌体;在含1200mmolL–1Zn2 的PDL(未加琼脂的PDA)中,接种分生孢子并连续培养7d后,菌体的Zn2 吸收量为258.3mgg-1干菌体。     

絮凝酵母吸附Cr(VI) 的机理

絮凝酵母SPSC01为酿酒酵母Saccharomyces cerevisiae和粟酒裂殖酵母Schizosaccharomyces pombe的融合菌株,用其吸附水溶液中的重金属Cr(VI),可以大大降低生物吸附的固液分离成本。为了探讨SPSC01菌体絮凝蛋白对Cr(VI) 还原吸附的影响,对SPSC01与其亲本菌株的吸附行为进行了比较。结果表明,SPSC01和其具有絮凝性状的亲本S. pombe的Cr(VI) 去除速率基本同步,远优于无絮凝性状的亲本S. cerevisiae;达到吸附平衡时,S. pombe、SPSC01和S. cerevisiae对总Cr去除率分别达68.8％、48.6％和37.5％;从而证明了絮凝有利于Cr(VI) 的还原、吸附,絮凝蛋白在Cr(VI) 的还原吸附过程中起促进作用。通过化学屏蔽方法和傅立叶变换红外光谱 (FTIR) 分析,对SPSC01菌体表面吸附Cr(VI) 的机理进行了研究,结果表明SPSC01菌体表面吸附Cr(VI) 起主要作用的基团是氨基、羧基和酰胺基。     

絮凝酵母吸附Cr(VI)的机理

絮凝酵母SPSC01为酿酒酵母Saccharomyces cerevisiae和粟酒裂殖酵母Schizosaccharomyces pombe的融合菌株,用其吸附水溶液中的重金属Cr(VI),可以大大降低生物吸附的固液分离成本。为了探讨SPSC01菌体絮凝蛋白对Cr(VI)还原吸附的影响,对SPSC01与其亲本菌株的吸附行为进行了比较。结果表明,SPSC01和其具有絮凝性状的亲本S.pombe的Cr(VI)去除速率基本同步,远优于无絮凝性状的亲本S.cerevisiae;达到吸附平衡时,S.pombe、SPSC01和S.cerevisiae对总Cr去除率分别达68.8%、48.6%和37.5%;从而证明了絮凝有利于Cr(VI)的还原、吸附,絮凝蛋白在Cr(VI)的还原吸附过程中起促进作用。通过化学屏蔽方法和傅立叶变换红外光谱(FTIR)分析,对SPSC01菌体表面吸附Cr(VI)的机理进行了研究,结果表明SPSC01菌体表面吸附Cr(VI)起主要作用的基团是氨基、羧基和酰胺基。     

Cadmium-Resistance Plasmid Affected Cd+2 Uptake More Than Cd+2 Adsorption in Klebsiella oxytoca

A bacterial strain was isolated from Petra City Wastewater Treatment Plant. This isolate was identified as Klebsiella oxytoca based on 16S rDNA analysis. A single plasmid (> 23 kb) was detected in this strain and transformed into Esherichia coli JM83. The transformed E. coli cells exhibited elevated resistance to cadmium as compared to parental plasmid-free cells. The sodium dodecyl sulfate (SDS)-treated cells showed higher efficiency in plasmid curing than the ethidium bromide–treated cells. The ethidium bromide–cured cells grew only in a 10 μ g/ml Cd^{+ 2} minimal tolerable concentration, whereas the SDS-treated cells had no growth in any of the Cd concentrations tested (2, 5, 10, 20, 30, 40, and 50 ppm). Contrary to the Freundlich model, the Langmuir model gave a good fit to the Cd biosorption data by K. oxytoca cells. Plasmid curing caused 80%, 82%, and 70% inhibition in the Cd biosorption, adsorption, and uptake, respectively. Furthermore, the absence of lysine decarboxylase (LDC) activity in the cured strain strongly implies that the structural gene-encoding LDC in this bacterium is plasmid encoded. After curing of the plasmid, 100% of the antibiotic-resistant loci were observed as chromosomal encoded. All of the results shown above indicated that the Cd resistance is plasmid mediated.     

土生鳞伞对Cd2+的吸附特性

以土生鳞伞（Pholiota terrestris Overh.）子实体为生物吸附剂吸附水溶液中的Cd2+,分析吸附剂用量、初始pH值、初始重金属浓度、反应时间这4个因素对吸附的影响,并采用Langmuir和Freundlich等温吸附模型及准一级、准二级动力学模型拟合土生鳞伞的生物吸附特性.结果表明:水溶液中Cd2+...     

A general model for biosorption of Cd2+, Cu2+ and Zn2+ by aerobic granules

Aerobic granules are microbial aggregates with a strong and compact structure. This study looked into the feasibility of aerobic granules as a novel type of biosorbent for the removal of individual Cd(2+), Cu(2+) and Zn(2+) from aqueous solution. Based on the thermodynamics of biosorption reaction, a general model was developed to describe the equilibrium biosorption of individual Cd(2+), Cu(2+) and Zn(2+) by aerobic granules. This model provides good insights into the thermodynamic mechanisms of biosorption of heavy metals. The model prediction was in good agreement with the experimental data obtained. It was further demonstrated that the Langmuir, Freundlich and Sips or Hill equations were particular cases of the proposed model. The biosorption capacity of individual Cd(2+), Cu(2+) and Zn(2+) on aerobic granules was 172.7, 59.6 and 164.5 mgg(-1), respectively. These values may imply that aerobic granules are effective biosorbent for the removal of Cd(2+), Cu(2+) and Zn(2+) from industrial wastewater.     

Atrazine degradation in saline wastewater by Pseudomonas sp strain ADP

Wastewater from atrazine manufacturing plants contains large amounts of residual atrazine and atrazine synthesis products, which must be removed before disposal. One of the obstacles to biological treatment of these wastewaters is their high salt content, eg, up to 4% NaCl (w/v). To enable biological treatment, bacteria capable of atrazine mineralization must be adapted to high-salinity conditions. A recently isolated atrazine-degrading bacterium, Pseudomonas sp strain ADP, originally isolated from contaminated soils was adapted to biodegradation of atrazine at salt concentrations relevant to atrazine manufacturing wastewater. The adaptation mechanism was based on the ability of the bacterium to produce trehalose as its main osmolyte. Trehalose accumulation was confirmed by natural-abundance ¹H NMR spectral analysis. The bacterium synthesized trehalose de novo in the cells, but could not utilize trehalose added to the growth medium. Interestingly, the bacterium could not produce glycine betaine (a common compatible solute), but addition of 1 mM of glycine betaine to the medium induced salt tolerance. Osmoregulated Pseudomonas sp strain ADP, feeding on citrate decreased the concentration of atrazine in non-sterile authentic wastewater from 25 ppm to below 1 ppm in less than 2 days. The results of our study suggest that salt-adapted Pseudomonas sp strain ADP can be used for atrazine degradation in salt-containing wastewater. Received 26 August 1997/ Accepted in revised form 06 December 1997     

Biosorption and Bio-Kinetic Properties of Solar Saltern Halobacterial Strains for Managing Zn2+, As2+ and Cd2+ Metals

Bacillus mucilaginosus has already been proved to be capable of degrading silicate minerals, but it is not very clear about the molecular mechanisms of bacterial mineral weathering. To understand the relationship between bacterial weathering of minerals and bacterial secreted proteins, B. mucilaginosus was chosen to study the expression of its extracellular proteins in the process of weathering potassium minerals. This article reveals that certain secreted proteins, related to weathering of potassium minerals, can be induced under conditions such as bacterial nutritional deficiency and the existence of K-bearing rock powders. This suggests direct evidence of the metabolic changes of extracellular enzymes in bacteria during the process of weathering of potassium minerals. It was speculated that these secreted proteins, together with extracellular polymers like polysaccharides, may accelerate the weathering of potassium minerals, resulting in the release of K⁺ needed for the bacterial growth.     

改性粉煤灰对废水中镉的吸附作用

以工业固废粉煤灰(FA)为原料,将其与NaOH和Ca(OH)₂混合后,在250 ℃下焙烧1.5 h,制得改性粉煤灰(MFA).利用扫描电镜(SEM)、能量色散X射线光谱仪(EDS)、X-射线衍射仪(XRD)、全自动比表面积分析仪(BET)和傅里叶红外光谱仪(FTIR)等技术分析MFA的理化性质.BET分析表明,MFA的比表面积比FA增大了20.6倍.SEM分析表明,FA表面玻璃相溶解,表面粗糙,具有多孔结构.FTIR分析表明,-OH官能团在Cd²⁺的吸附过程中具有重要作用.静态吸附试验研究表明,当MFA的投加量为0.2 g、Cd²⁺初始浓度为100 mg·L^-1、溶液pH为7、25 ℃下吸附90 min时,Cd²⁺的去除率达到97.3%;共存阳离子(K⁺、Na⁺、Mg²⁺和Ca²⁺)均会抑制MFA对Cd²⁺的吸附,其中Ca²⁺的抑制作用最强.Langmuir等温吸附模型和准二级吸附动力学方程能较好地描述Cd²⁺在MFA上的吸附行为,且最大吸附量为55.77 mg·g^-1.热力学研究表明,MFA对Cd²⁺的吸附是一个自发的吸热过程.MFA吸附能力优于FA,在废水处理方面有一定的应用前景.