废啤酒酵母吸附水溶液中Cu2+的性能及机理研究

用废啤酒酵母吸附水溶液中Cu2+,考察了溶液pH值、Cu2+浓度和吸附时间对Cu2+吸附的影响。结果表明：废啤酒酵母吸附Cu2+在4-6个小时内达到吸附平衡,酸性条件利于吸附,以pH为5时最佳,吸附等温曲线符合Langmuir模式。用电位滴定及FTIR分析的方法确定生物吸附剂主要含有磺酸基、羧基及氨基等功能团。生物吸附剂对Cu2+的吸附以单分子层的化学吸附为主,功能团在不同的pH条件下呈现不同的电离性能,在吸附过程中发挥重要作用。     

大宝山矿区耐Cd2+细菌的分离鉴定及其生物学特性

【目的】从Cd2+污染土壤中分离获取强耐Cd2+微生物,研究其生物学特性。【方法】采用选择性培养基TSA对广东省大宝山重金属污染土壤中耐镉(Cd2+)细菌进行分离筛选,结合细菌形态观察、生理生化检测、16S rRNA基因序列分析等方法确定了它们的分类地位,并开展了细胞形态、Cd2+耐受性、Cd2+吸附性、对不同pH和盐度适应性、以及对抗生素的抗性等生物学特性的研究。【结果】从土壤中分离到8株具有强耐Cd2+能力的细菌(YN-6、YN-7、YN-8、YN-9、YN-16、YN-17、YN-18、YN-19),初步鉴定其分别属于Rhizobium、Roseateles、Cupriavidus、Methylobacterium、Variovorax、Rhizobium、Achromobacter和Leifsonia属。细菌生物学特性研究表明,8株耐Cd2+细菌的形态存在一定的差异,其中YN-6、YN-8、YN-9、YN-16、YN-17和YN-18菌体为短杆状,而YN-7和YN-19菌体为长杆状。它们对Cd2+的最低抑制浓度均在3 mmol/L以上,且每克细胞吸附1 mg以上的Cd2+。其中,菌株YN-8对Cd2+的耐受性最强(9 mmol/L),菌株YN-9对Cd2+的吸附能力最强(316.7 mg Cd2+/g cells)。不同pH、盐度和抗生素对8株细菌生长的影响存在较大差异。【结论】菌株YN-8和YN-9对环境的适应性较强,可以作为较好的试验材料应用于生物修复重金属Cd2+污染土壤的研究。     

植物乳杆菌对重金属Pb~(2+)、Cr~(6+)和Cu~(2+)的耐受性与吸附作用相关性比较

从四川矿区泡菜样品中分离得到1株对重金属铅(Pb)、铬(Cr)和铜(Cu)具有较高耐受性的菌株,经16S rDNA初步鉴定为1株植物乳杆菌。研究重金属铅、铬和铜对该植物乳杆菌的最小抑制浓度(MIC)。比较不同初始pH、初始离子浓度、吸附时间和菌体加入量对植物乳杆菌吸附3种重金属的影响,探讨MIC与吸附作用相关性。使用MIC的方法测定重金属对该菌的最小抑制浓度,原子吸收法测定对重金属的吸附效果。研究表明,该菌对Pb~(2+)、Cr~(6+)和Cu~(2+)的耐受性分别为6.67、0.67和2.17 mmol/L;其吸附性最适初始pH分别为4、6和6;最优初始离子浓度分别为100、100和50 mg/L;最优加菌量分别为3、6和5 g/L;最佳吸附时间分别为12、2和8 h。在100 mg/L的初始离子浓度下对Pb~(2+)、Cr~(6+)和Cu~(2+)的吸附率最高分别可达96%、61%和49%。MIC与吸附作用没有明显相关性。结果表明该菌具有优良的吸附性能,为今后含有乳酸菌的食品或饲料制剂的开发提供了新的乳酸菌种。     

一株耐Cd菌株的分离、鉴定及基本特性

【目的】从活性污泥中筛选耐镉(Cd)菌株,并研究其生长特性及对溶液中Cd~(2+)吸附的最佳条件,以期为重金属Cd污染水体的微生物修复提供菌株资源和应用技术参考。【方法】采用平板划线法,从活性污泥中分离、筛选、驯化出耐Cd菌株,通过16SrRNA基因序列分析及溶血试验、蛋白质毒素结晶试验进行初步鉴定,并采用单因素实验优化菌株的培养条件,通过正交实验确定菌粉吸附溶液中Cd~(2+)的最佳条件,同时利用SEM-EDS及FTIR分析探讨菌粉吸附Cd~(2+)的机理。【结果】经分离、驯化得到1株耐Cd细菌菌株,命名为H6,初步鉴定为蜡样芽孢杆菌(Bacilluscereus),最大Cd~(2+)耐受浓度为350 mg/L。菌株H6的最佳生长条件为:pH 6.0–8.0,温度28°C,转速120–210 r/min,接种量1%–5%;菌株H6在生长过程中,培养液pH值先稍微下降然后不断上升。菌粉吸附Cd~(2+)的正交优化条件为:菌粉用量0.125 g/L,吸附时间2 h,pH 5.0,温度30°C,此条件下吸附量为205 mg/g。SEM-EDS分析和红外光谱(FTIR)分析表明,在吸附过程中主要作用基团有羟基、羧基、羰基、酰胺基和烷基,此外,Ca~(2+)与Cd~(2+)发生了离子交换。【结论】从活性污泥中分离出的菌株H6,初步鉴定为蜡样芽孢杆菌(Bacillus cereus),是1株具有较强Cd~(2+)吸附能力的细菌菌株。     

生物硫铁生成菌的选育及处理重金属效果研究

[目的]分离高产生物硫铁生成菌,初步鉴定并研究其生成限制因素及处理重金属效果。[方法]利用分离驯化出的1株高产生物硫铁复合材料(生物硫铁)的硫酸盐还原菌(srb1),考察硫酸亚铁浓度、有机物浓度以及搅拌速度对其生成生物硫铁的影响。[结果]有机物和Fe SO4·7H2O的浓度是制约生物硫铁生成的关键因素,生物硫铁处理重金属Cr6+、Pb2+、Cd2+、Cu2+效果显著,去除率达90%以上,尤其是处理重金属Cu2+废水最佳,去除率达99%以上。[结论]筛选到生物硫铁生成菌srb1,初步鉴定为梭状芽胞杆菌属Clostridium mesophilum。确定了生物硫铁生成的最佳培养条件为乳酸钠15 m L/L+酵母膏8 g/L+Fe SO4·7H2O 15 g/L。     

污泥中重金属的生物淋滤

生物淋滤法(Bioleaching)是指利用自然界中一些微生物(硫细菌)的直接作用或其代谢产物的间接作用,产生氧化、还原、络合、吸附或溶解反应,将固相中某些不溶性成分(如重金属、硫及其他金属)分离浸提出来的技术.在生物淋滤中,嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)和嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans,A.f)被用作有效的淋滤载体[1].这种嗜酸性的化能自养型细菌以大气中的CO2为碳源,以无机物铁或硫为能源来维持生长,不需要提供外来的碳源和电子供体.另外,由于pH值很低,抑制了其他细菌的生长,所以在实际的操作过程中不需要严格的无菌条件.氧化亚铁硫杆菌和氧化硫硫杆菌去除重金属适宜于污水处理厂的开放系统,采用土著嗜酸性氧化亚铁硫杆菌(A.f)和氧化硫硫杆菌(A.f)进行重金属去除.也就是说,处理什么地方的污泥,就在什么地方分离A.f和A.t,这样分离的微生物在生物淋滤过程中能发挥较好的作用.这也是微生物在自然界生长繁殖的特点之一. 本期介绍了王聪、宋存江等[2]从剩余活性污泥中分离得到两株土著硫杆菌,对两株菌进行了分类鉴定,确定二者分别为嗜酸性氧化亚铁硫杆菌杆(Acidithiobacillus ferrooxidans,A.f)和嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans,A.t),将二者的单菌和混合菌分别接种于剩余活性污泥中,进行了为期9 d的生物淋滤,对淋滤过程中的pH变化、氧化还原电位(ORP)以及重金属含量进行了检测.结果表明,生物淋滤9 d的混合菌对于As、Cr、Cu、Ni和Zn的去除效果最好,去除率分别达到了96.09%、93.47%、98.32%、97.88%和98.60%.混合菌生物淋滤对于Cd和Pb的去除率在第6天之后迅速下降,但是A.t单菌淋滤保持较高的去除率,此结果为进一步的应用打下了良好的基础.     

从铅锌矿渣中分离的微生物对重金属吸附特性的研究

从铅锌矿渣中分离到 16种菌 (包括 7株细菌和 9株真菌 ) ,并研究了它们对Zn2 + ,Pb2 + ,Cu2 + 的吸附特性。发现大多数菌株对Pb2 + 与Zn2 + 有不同程度的吸附 ,但对Cu2 + 的吸附能力较小。菌株对Zn2 + 的吸附率大于对Pb2 + 的吸附 ,能吸附Pb2 + 的菌株也能吸附Zn2 + 。pH 4～ 6是真菌吸附金属离子的较好范围 ,细菌仅在pH =5 .0条件下 ,对Pb2 + 与Zn2 + 有吸附。在测试的不同金属离子浓度范围内 (5 0mg/L 相似文献   

铜矿厂区土壤中耐铜菌株的筛选及其生长特性初探

为了筛选和开发能够治理重金属污染的微生物资源,运用梯度驯化筛选法和单因素变量法分别对铜矿厂区土壤中的耐铜微生物进行了筛选及其生产培养条件的研究。结果表明,一株耐铜微生物Cladosporium sp.能耐受Cu2+的浓度达15 000 mg/L。在优化的培养时间96 h,转速150r/min,温度28℃,p H 6.0下该菌的耐铜性可提高3.62倍,达到54 300 mg/L,对环境中铜离子的吸附能力可提高2.27倍,达到38.19 mg/g。该菌对重金属Cu2+有非常高的耐受和吸附特性,可作为今后微生物治理重金属污染的优良备选菌种,其耐重金属基因也可作为基因工程的实验研究材料。     

盐土粘细菌NUST03的非活性菌体对重金属离子的吸附研究

研究盐土粘细菌NUST03对Cu2+、Cr3+、Ni2+的吸附能力及不同条件下菌体对离子的吸附。实验表明盐土粘细菌NUST03对Cu2+、Cr3+、Ni2+吸附能力为Cu2+>Cr3+>Ni2+,pH值对菌体吸附Cu2+、Ni2+影响较大,氯化钙和氯化镁的存在对菌体吸附Cu2+、Ni2+、Cr3+有一定的抑制作用。     

海南万宁海域海洋生物重金属分析与评价

海洋经济生物体内重金属含量直接影响到人类健康。根据2020年12月对万宁海域12个调查站、10种生物(鱼类7种、软体类1种、甲壳类2种)体内的7种重金属(Cu、Pb、Zn、Cd、Cr、As、Hg)含量监测结果,分析了重金属的含量特征,并分别利用单因子污染指数法和重金属富集系数对重金属污染水平和它在生物体内的富集情况进行了评价。结果表明:(1)各类生物体内重金属含量的高低顺序不一致,但三类生物体内锌和铜的含量均相对较高。生物对必需元素锌和铜的富集明显高于对非必需元素铅、镉和总汞的,主动吸收能力明显。(2)不同类生物同种重金属的含量存在一定差异,甲壳类的高于鱼类和软体类的。万宁海域鱼类和软体类生物重金属单因子污染指数均小于1,部分甲壳类生物的铬单因子污染指数大于1,超标率为41.7%。铬是万宁海域海洋生物的主要污染因子,影响其含量的原因可能是周围的围填海工程,以及所研究物种的生理特性。(3)万宁海域甲壳类生物体内总汞已呈轻污染状态,铬呈重污染状态。(4)甲壳类生物对重金属的富集能力强于鱼类和软体类的,各类生物对Cu的富集能力最高,对As的富集能力最低,且对重金属Cu、Cd和Zn有潜在的严重...     

Biosorption of Copper(II) by Live and Dried Biomass of the White Rot Fungi Phanerochaete chrysosporium and Funalia trogii

Biosorption is an innovative and alternative technology to remove heavy metal pollutants from aqueous solution using live, inactive and dead biomasses such as algae, bacteria and fungi. In this study, live and dried biomass of Phanerochaete chrysosporium and Funalia trogii was applied as heavy metal adsorbent material. Biosorption of copper(II) cations in aqueous solution by live and dried biomass of Phanerochaete chrysosporium and Funalia trogii was investigated to study the effects of initial heavy metal concentration, pH, temperature, contact time, agitation rate and amount of fungus. Copper(II) was taken up quickly by fungal biomass (live or dried) during the first 15 min and the most important factor which affected the copper adsorption by live and dried biomass was the pH value. An initial pH of around 5.0 allowed for an optimum adsorption performance. Live biomass of two white rot fungi showed a high copper adsorption capacity compared with dried biomass. Copper(II) uptake was found to be independent of temperature in the range of 20–45 °C. The initial metal ion concentration (10–300 mg/L) significantly influenced the biosorption capacity of these fungi. The results indicate that a biosorption as high as 40–60 % by live and dried biomass can be obtained under optimum conditions.     

Metal biosorption by surface-layer proteins from Bacillus species

Bacillus species have been involved in metal association as biosorbents, but there is not a clear understanding of this chelating property. In order to evaluate this metal chelating capacity, cultures and spores from Grampositive bacteria of species either able or unable to produce surface layer proteins (S-layers) were analyzed for their capacity of copper biosorption. Only those endowed of S-layers, like Bacillus sphaericus and B. thuringiensis, showed a significant biosorption capacity. This capacity (nearly 50%) was retained after heating of cultures, thus supporting that structural elements of the envelopes are responsible for such activity. Purified Slayers from two Bacillus sphaericus strains had the ability to biosorb copper. Copper biosorption parameters were determined for strain B. sphaericus 2362, and after analyses by means of the Langmuir model, the affinity and capacity were shown to be comparable to other bacterial biosorbents. A competitive effect of Ca2+ and Zn2+, but not of Cd2+, was also observed, thus indicating that other cations may be biosorbed by this protein. Spores that have been shown to be proficient for copper biosorption were further analyzed for the presence of Slayer content. The retention of S-layers by these spores was clearly observed, and after extensive treatment to eliminate the S-layers, the biosorption capacity of these spores was significantly reduced. For the first time, a direct correlation between S-layer protein content and metal biosorption capacity is shown. This capacity is linked to the retention of S-layer proteins attached to Bacillus spores and cells.     

Biosorption of heavy metals by Bacillus thuringiensis strain OSM29 originating from industrial effluent contaminated north Indian soil

The study was navigated to examine the metal biosorbing ability of bacterial strain OSM29 recovered from rhizosphere of cauliflower grown in soil irrigated consistently with industrial effluents. The metal tolerant bacterial strain OSM29 was identified as Bacillus thuringiensis following 16S rRNA gene sequence analysis. In the presence of the varying concentrations (25–150 mgl⁻¹) of heavy metals, such as cadmium, chromium, copper, lead and nickel, the B. thuringiensis strain OSM29 showed an obvious metal removing potential. The effect of certain physico-chemical factors such as pH, initial metal concentration, and contact time on biosorption was also assessed. The optimum pH for nickel and chromium removal was 7, while for cadmium, copper and lead, it was 6. The optimal contact time was 30 min. for each metal at 32 ± 2 °C by strain OSM29. The biosorption capacity of the strain OSM29 for the metallic ions was highest for Ni (94%) which was followed by Cu (91.8%), while the lowest sorption by bacterial biomass was recorded for Cd (87%) at 25 mgl⁻¹ initial metal ion concentration. The regression coefficients obtained for heavy metals from the Freundlich and Langmuir models were significant. The surface chemical functional groups of B. thuringiensis biomass identified by Fourier transform infrared (FTIR) were amino, carboxyl, hydroxyl, and carbonyl groups, which may be involved in the biosorption of heavy metals. The biosorption ability of B. thuringiensis OSM29 varied with metals and was pH and metal concentration dependent. The biosorption of each metal was fairly rapid which could be an advantage for large scale treatment of contaminated sites.     

Biosorption of Cadmium and Manganese Using Free Cells of Klebsiella sp. Isolated from Waste Water

In the present study, we evaluated a bacterium that was isolated from waste water for its ability to take up cadmium and manganese. The strain, identified both biochemically and by its 16S rRNA gene sequence as Klebsiella, was named Yangling I2 and was found to be highly resistant to heavy metals. Surface characterization of the bacterium via SEM revealed gross morphological changes, with cells appearing as biconcave discs after metal exposure rather than their typical rod shape. The effects of pH, temperature, heavy metal concentration, agitation and biomass concentration on the uptake of Cd(II) and Mn(II) was measured using atomic absorption spectrophotometry. The results showed that the biosorption was most affected by pH and incubation temperature, being maximized at pH 5.0 and 30°C, with absorption capacities of 170.4 and 114.1 mg/g for Cd(II) and Mn(II), respectively. Two models were investigated to compare the cells’ capacity for the biosorption of Cd and Mn, and the Langmuir model based on fuzzy linear regression was found to be close to the observed absorption curves and yield binding constants of 0.98 and 0.86 for Cd and Mn, respectively. This strain of Klebsiella has approximately ten times the absorption capacity reported for other strains and is promising for the removal of heavy metals from waste water.     

An ecofriendly approach for bioremediation of contaminated water environment: Potential contribution of a coastal seaweed community to environmental improvement

High levels of heavy metals like copper ions in many industrial based effluents lead to serious environmental and health problems. Biosorption is a potential environmental biotechnology approach for biotreatment of aquatic sites polluted with heavy metal ions. Seaweeds have received great attention for their high bioremediation potential in recent years. However, the co-application of marine macroalgae for removal of heavy metals from wastewater is very limited. Thus, for the first time in literature, a coastal seaweed community composed of Chaetomorpha sp., Polysiphonia sp., Ulva sp. and Cystoseira sp. species was applied to remove copper ions from synthetic aqueous medium in this study. The biosorption experiments in batch mode were conducted to examine the effects of operating variables including pH, biosorbent amount, metal ion concentration and contact time on the biosorption process. The biosorption behavior of biosorbent was described by various equilibrium, kinetic and thermodynamic models. The biosorption of copper ions was strongly influenced by the operating parameters. The results indicated that the equilibrium data of biosorption were best modeled by Sips isotherm model. The values of mean free energy of biosorption computed from Dubinin-Radushkevich isotherm model and the standard Gibbs free energy change indicated a feasible, spontaneous and physical biotreatment system. The pseudo-second-order rate equation successfully defined the kinetic behavior of copper biosorption. The pore diffusion also played role in the control of biosorption process. The maximum copper uptake capacity of biosorbent was found to be greater than those of many other biosorbents. The obtained results revealed that this novel biosorbent could be a promising material for copper ion bioremediation implementations.     

Presence of the fish pathogen Vibrio salmonicida in fish farm sediments

The persistence of the fish pathogen Vibrio salmonicida in fish farm sediments was studied by use of fluorescent-antibody techniques. The specificities of the monoclonal antibodies and polyclonal rabbit serum used in the study were tested against a number of Vibrio strains, including 4 isolates from intestinal tracts of healthy fish and 98 isolates from sediments. V. salmonicida was detected in sediment samples from diseased farms several months after an outbreak of the disease. The bacterium was also detected in a sediment sample from a disease-free fish farm. No V. salmonicida could be detected in sediments not influenced by fish farming. The number of positive samples was generally higher with application of rabbit serum as opposed to use of monoclonal antibodies, indicating that the rabbit serum may cross-react with other bacteria.     

Broad diversity of conjugative plasmids in integron-carrying bacteria from wastewater environments

In this study we assessed the occurrence, diversity and conjugative potential of plasmids in integron-carrying Aeromonas and Enterobacteriaceae from wastewaters. Sixty-six strains were included as donors in mating assays using rifampicin-resistant Escherichia coli and Pseudomonas putida recipient strains. The diversity of plasmids from donors and transconjugants (resistant to tetracycline or streptomycin) was evaluated by restriction analysis and replicon typing targeting 19 incompatibility groups. Restriction patterns revealed a diverse plasmid pool present in these strains. Plasmids were assigned to FrepB (Aeromonas salmonicida, Aeromonas veronii, Aeromonas sp., E.?coli, Enterobacter sp.), FIC (A.?salmonicida, Aeromonas sp.), FIA (Shigella sp.), I1 (A.?veronii, Aeromonas sp., E.?coli), HI1 (E.?coli) and U (Aeromonas media) replicons. Nevertheless, 50% of the plasmids could not be assigned to any replicon type. Among integron-positive transconjugants, FrepB, I1 and HI1 replicons were detected. Results showed that wastewaters enclose a rich plasmid pool associated with integron-carrying bacteria, capable of conjugating to different bacterial hosts. Moreover, replicons detected in this study in Aeromonas strains expand our current knowledge of plasmid diversity in this genus.     

Biosorption of heavy metals by Saccharomyces cerevisiae: a review

Heavy metal pollution has become one of the most serious environmental problems today. Biosorption, using biomaterials such as bacteria, fungi, yeast and algae, is regarded as a cost-effective biotechnology for the treatment of high volume and low concentration complex wastewaters containing heavy metal(s) in the order of 1 to 100 mg/L. Among the promising biosorbents for heavy metal removal which have been researched during the past decades, Saccharomyces cerevisiae has received increasing attention due to the unique nature in spite of its mediocre capacity for metal uptake compared with other fungi. S. cerevisiae is widely used in food and beverage production, is easily cultivated using cheap media, is also a by-product in large quantity as a waste of the fermentation industry, and is easily manipulated at molecular level. The state of the art in the field of biosorption of heavy metals by S. cerevisiae not only in China, but also worldwide, is reviewed in this paper, based on a substantial number of relevant references published recently on the background of biosorption achievements and development. Characteristics of S. cerevisiae in heavy metal biosorption are extensively discussed. The yeast can be studied in various forms for different purposes. Metal-binding capacity for various heavy metals by S. cerevisiae under different conditions is compared. Lead and uranium, for instances, could be removed from dilute solutions more effectively in comparison with other metals. The yeast biosorption largely depends on parameters such as pH, the ratio of the initial metal ion and initial biomass concentration, culture conditions, presence of various ligands and competitive metal ions in solution and to a limited extent on temperature. An assessment of the isotherm equilibrium model, as well as kinetics was performed. The mechanisms of biosorption are understood only to a limited extent. Elucidation of the mechanism of metal uptake is a real challenge in the field of biosorption. Various mechanism assumptions of metal uptake by S. cerevisiae are summarized.     

Probiotic bacteria as potential detoxification tools: assessing their heavy metal binding isotherms

Dietary exposure to heavy metals may have detrimental effects on human and animal health, even at low concentrations. Specific probiotic bacteria may have properties that enable them to bind toxins from food and water. We assessed the interaction of probiotic bacteria with cadmium and lead in vitro as an initial screening step to identify strains for heavy metal decontamination in food and intestinal models. Binding isotherms for cadmium and lead were characterized for Lactobacillus rhamnosus LC-705, Propionibacterium freudenreichii subsp. shermanii JS and a mix of them used by the food industry. Differences among the strains and their combinations in binding performance at a range of concentrations between 0.1 and 100 mg.L-1 were evaluated with the Langmuir model for biosorption. The effects of pH, contact time, and viability on the binding capacities were also investigated. All strains and their combinations were found to bind cadmium and lead efficiently at low concentration ranges commonly observed in foods. However, the two strains and their combinations differed significantly in their maximum binding capacities and affinities represented by the Langmuir constants Qmax and b, respectively. The binding seemed to occur instantaneously and in a pH-dependent manner, which can be perfectly described by a segmented linear-plateau model.     

A rapid screening method for the isolation of metal-accumulating microorganisms

Summary An agar plate screening method was developed for the rapid isolation of heavy metal-accumulating microorganisms and preliminary estimation of their biosorption capacity. The test is based on the visulaization and interpretation of the metal distribution between agar and colonies by chemical preciptitation with hydrogen sulphide or ammonium sulphide. The heavy metals silver, thallium, lead, copper, nickel and cadmium have been tested successfully. The efficiency of the method is demonstrated for isolating silver-accumulating bacterian and estimating silver biosorption capacity.