产脲酶微生物矿化修复铜污染溶液效果研究

MINERALIZATION EFFECT OF UREASE-PRODUCING MICROORGANISMS ON COPPER IN SOLUTION

从山西省襄垣县矿区土壤中筛选出1株产脲酶菌株,以水溶液中铜为研究对象,并以巴氏芽孢杆菌作为对照,基于微生物诱导碳酸盐沉淀和酶诱导碳酸盐沉淀技术,探究2种菌株及其脲酶液对溶液中Cu^(2+)的矿化效果。结果表明:产脲酶微生物在培养温度为35℃时,在培养24 h后微生物生长量达到最佳水平,此时自筛产脲酶菌和巴氏芽孢杆菌的脲酶活性分别为7.27,8.59 mmol/L/min,对溶液中的尿素水解量分别为8.08,9.54 mmol/L。在反应液中的尿素与氯化钙浓度均为1.5 mol/L的条件下,2种细菌菌液及其脲酶液对初始浓度为250 mg/L的Cu^(2+)沉淀率最高。此时,自筛产脲酶菌和巴氏芽孢杆菌对溶液中Cu^(2+)的沉淀率分别达到64.28%和69.30%;与胞外脲酶相比,细菌胞内脲酶对Cu^(2+)的沉淀效果更显著,自筛产脲酶菌和巴氏芽孢杆菌胞内脲酶液对Cu^(2+)的沉淀率最高达到41.00%和53.41%。

A urease-producing bacterial strain was screened from the soil of Xiangyuan County,Shanxi Province.Taking the Bacillus pasteurii as a control,the precipitation effect of the two bacteria and their urease solution on copper in solution was studied.The results showed that the best level of microbial biomass was observed after 24 h when the incubation temperature was 35℃.At this time,the urease activity of self-screening urease-producing bacteria and Bacillus pasteurii was 7.27 mmol/L/min and 8.59 mmol/L/min,respectively.And the amount of urea hydrolysis in the solution by self-screening urease-producing bacteria and Bacillus pasteurii was 8.08 mmol/L and 9.54 mmol/L,respectively.When the concentration of urea and calcium chloride in the reaction solution were 1.5 mol/L,the precipitation rate of Cu^(2+)with initial concentration of 250 mg/L was the highest.And the highest precipitation rates of Cu^(2+)by self-screening urease-producing bacteria and Bacillus pasteurii were 64.28%and 69.30%,respectively.Comparing with bacterial extracellular urease,the precipitation effect of intracellular urease on Cu^(2+)was much stronger,with precipitation rates of 41.00%and 53.41%,for self-screened urease-producing bacteria and Bacillus pasteurii,respectively.