一株碳酸盐矿化菌的分离鉴定及其对Cu的固定作用  

Isolation and identification of Achromobacter xylosoxidans LAX2 for Cu immobilization

作　　者：李哲 张欢 张秀芳[1,2] 周野 吴迪 李明堂[1,2] LI Zhe ZHANG nuan ZHANG Xiufang ZHOU Ye WU Di LI Mingtang(College of Resource and Environmental Science, Jilin Agricultural University, Changehun 130118 Key Laboratory of Soil Resource Sustainable Utilization for Jilin Province Commodity Grain Bases, Changehun 130118)

机构地区：[1]吉林农业大学资源与环境学院,长春130118 [2]吉林省商品粮基地土壤资源可持续利用重点实验室,长春130118

出　　处：《环境科学学报》2017年第10期3687-3695,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.51109089);吉林省科技发展计划项目(No.20160204025SF)~~

摘　　要：有机肥的大量使用使得菜田土壤重金属含量呈快速的累积趋势,对蔬菜安全生产构成了严重的威胁.本文从长期施加鸡粪猪粪等农家肥的大棚蔬菜根际土壤中筛选出了一株能降解尿素释放碳酸根,进而通过生物矿化作用固结重金属的细菌,系统发育分析和生理生化特征表明该菌株为氧化木糖无色杆菌,将其命名为LAX2.菌株LAX2可在含尿素的培养基中快速生长,所产脲酶的活力可达140 U·m L^(-1),发酵液的pH可达9.06.菌株LAX2可耐受浓度高达115 mg·L^(-1)的铜离子.X-射线衍射分析(XRD)、傅里叶红外光谱分析(FTIR)、扫描电子显微镜(SEM)和能谱(EDS)分析表明菌株LAX2可通过生物矿化作用形成微球形的Cu_2(OH)_2CO_3,其直径可达2μm.菌体细胞吸附、生物矿化和化学沉淀对溶液中Cu^(2+)的去除率分别为93%、85%和72%.菌株LAX2对土壤中有效态Cu的固定作用呈现适应-快速-慢速3个阶段,培养5、10和30 d后土壤有效态Cu的含量分别下降了52.3%、73.7%和87.4%.与菌体细胞吸附和化学沉淀相比,生物矿化作用固定的Cu对短期内的淹水和反复冻融具有很强的抗性作用.以上结果表明菌株LAX2可通过生物成矿作用形成性质较稳定的碳酸铜矿物,在土壤铜污染修复方面具有重要的应用价值.Heavy metal content in vegetable soil shows obvious accumulation trend due to the large use of organic fertilizer,which poses a serious threat to the safety of vegetable production. A bacterium strain,carring the ability to degrade urea and precipitate heavy metals through bio-mineralization,was isolated from the vegetable rhizosphere soil with long-term application of farm manure,such as chicken and pig manure. According to the results of phylogenetic analysis,physiological and biochemical characterization,this strain was named as Achromobacter xylosoxidans LAX2. Strain LAX2 grew rapidly in urea-containing medium,producing urease with the highest activity of 140 U·m L^-1under pH 9.06 in fermentation broth. Strain LAX2 is copper resisted with the highest tolerance concentration of 115 mg·L^-1. Results of X-ray diffraction（ XRD）,Fourier transform infrared spectroscopy（ FTIR）,scanning electron microscopy（ SEM） and energy dispersive spectroscopy（ EDS） analysis show that the bio-mineralized product was Cu2（ OH）2CO3and micro-spherical shape with diameter of 2 μm. The removal rate of Cu2＋by bacterial cell adsorption,biomineralization and chemical precipitation were93%,85% and 72% respectively. The immobilization of available Cu in soil by strain LAX2 presented three phases,such as adaption,fast and slow rate phases. The content of available Cu in soil decreased by 52. 3%,73. 7% and 87. 4%,respectively,after 5,10 and 30 days of bacrterium cultivation.Immobilized Cu shows strong resistance to short-term flooding and repeated freezing and thawing,compared with bioadsorption and chemical precipitation.Results of this study indicate that strain LAX2 could form stable carbonate minerals by biomineralization and have application potential in Cu-polluted soil remediation.

关 键 词：生物矿化 氧化木糖无色杆菌 有效态Cu 脲酶 土壤污染修复 

分 类 号：X172[环境科学与工程—环境科学]