麦田土壤中抗铅菌株筛选及其吸附特性的研究

为研究铅污染土壤中微生物对重金属铅的耐受性及去除效果,从铅污染土壤中分离、筛选出2株抗铅菌株(BY-10和FB-6),研究其对铅的吸附特性、最佳生长条件,并对其进行鉴定。结果表明:菌株BY-10和FB-6分别为蜡状芽孢杆菌和团青霉。它们对铅的耐受质量浓度分别高达1 700,2 500 mg/L。菌株的生长条件范围较广,蜡状芽孢杆菌最适温度为35℃,团青霉最适温度为30℃;最适p H值均为7;最适装液量均为80~100 m L(250 m L摇瓶)。在初始铅质量浓度为0~600 mg/L内,随着浓度增加,菌株生长逐渐减缓,在≥400 mg/L的铅培养液中,团青霉与蜡状芽孢杆菌相比对铅的耐受性较强。在铅质量浓度一定时,随着生长时间的延长,菌株对铅的吸附率表现出先增大后减小的趋势,生物吸附量表现出同样趋势。而生长时间一定时,随着铅质量浓度的不断升高,菌株的吸附率逐渐降低,生物吸附量呈上升趋势。在铅质量浓度为150 mg/L时,蜡状芽孢杆菌和团青霉对铅的去除率达到最大,分别为66.25%和74.88%。

Screening of Lead Resistance Strains and Their Absorption Characteristics in Wheat Field Soil

This study focuses on the lead tolerance and removal efficiency of microorganisms from the lead-contaminated soil.Two lead-resistant strains denoted by BY-10 and FB-6 were isolated from contaminated soil around a lead refinery.And the lead biosorption characteristics and optimal growth conditions of the strains were studied.The results showed that strains BY-10 and FB-6 belonged to Bacillus cereus and Penicillium commune respectively,and their tolerance concentrations to lead were 1 700,2 500 mg/L,respectively.In addition,the strains had a wide range of growing conditions.The optimal temperature of Bacillus cereus was 35 ℃ and that of Penicillium commune was 30 ℃.For both Bacillus cereus and Penicillium commune,the optimal growth pH was 7 and the liquid medium volume was 80-100 mL (in 250 mL bottle).With the increase of initial lead concentration from 0 to 600 mg/L,the growth of two strains became slower and slower gradually,while the tolerance of Penicillium commune to lead was stronger than that of Bacillus cereus when the lead concentration was over 400 mg/L.At a certain concentration of lead,the lead adsorption rate of the two strains increased firstly and then decreased gradually with the increasing growth time of strains.The dynamic change of biological adsorption quantity of lead by the two strains was similar to the adsorption rate of lead.But in a certain growth time of strains,there was a descending trend in the adsorption rate of strains to lead and an ascending trend in the biological adsorption quantity of them with the increase of lead concentration.Furthermore,the lead adsorption rate of Bacillus cereus and Penicillium commune reached the top at the 150 mg/L concentration of lead,and their values were 66.25％ and 74.88％ respectively.