预氧化联合激活剂促进微生物长效降解土壤中烷烃的研究

Long-Term Effective Degradation of Alkanes in Soil by Microorganisms Enhanced by Pre-Oxidation Combined with Activator

微生物降解是一种修复石油污染土壤中烷烃的技术,但该技术易受环境条件影响,修复效率较低。为找到一种使土壤微生物能够长期有效降解烷烃的方法,进行了预氧化联合微生物激活剂降解土壤中烷烃的研究,其中利用芬顿反应进行预氧化,微生物激活剂由葡萄糖和乙酸共同组成。通过激活组(预氧化结合激活剂)、非激活组Ⅰ(仅添加激活剂,不进行预氧化)、非激活组Ⅱ(仅进行预氧化,不添加激活剂)和空白组4种不同处理方法,探究石油污染土壤微生物的数量、呼吸活性、种群变化对烷烃降解效果的影响。结果表明:激活组中烷烃半衰期只需64 d,比非激活组Ⅱ缩短了333 d,其烷烃降解率长期维持较高值,其中0~20 d、20~40 d和40~60 d的降解率分别为14.23%、17.93%和15.73%,且每20 d的烷烃降解量均维持在1500 mg/kg以上。然而其他3组的烷烃降解率随着时间推移而显著降低,40~60 d时烷烃降解率最高仅有5.50%。预氧化后土壤中类腐殖酸和类富里酸的荧光标准积分体积分别是土壤氧化前的2.80倍和3.82倍,预氧化促进了土壤微生物的快速增长。在添加乙酸和葡萄糖后土壤微生物被激活,激活剂的利用率分别达到88.06%和91.38%,其土壤微生物呼吸活性(以每kg土壤中微生物产生CO_(2)的物质的量计,下同)维持在5.00 mol/kg以上,而非激活组的土壤微生物呼吸活性在40~60 d时最高只达到2.12 mol/kg。此外,激活组的石油降解菌数量(以每g土壤中含有的石油降解菌数量计)在后期超过了9.00 lg(CFU/g),形成了芽孢杆菌属、不动杆菌属、微杆菌属、链霉菌属和水杆菌属5种优势菌属,而非激活组最多只形成了3种优势菌属。研究显示,微生物长效降解土壤中的烷烃主要由其呼吸活性、石油降解菌数量、优势菌属数和营养利用率驱动。研究结果为解决土壤石油污染问题提供了一种经济有效的方法。

Microbial degradation is a technology for remediating alkanes in petroleum-contaminated soil.However,it is susceptible to environmental conditions and has low remediation efficiency.To find a method to enable soil microorganisms to effectively degrade alkanes in the long term,a study on the degradation of alkanes in soil by pre-oxidation combined with a microbial activator was carried out,in which Fenton reaction was used for pre-oxidation,and the microbial activator consisted of a combination of glucose and acetic acid.The study examined the effects of petroleum-contaminated soil microbial quantity,respiration activity,and population changes on alkanes biodegradation by four different treatments:activated group(pre-oxidation and activator),non-activated groupⅠ(activator only,without pre-oxidation),non-activated group Ⅱ(pre-oxidation only,without activator),and control group.The results showed that the half-life of alkanes in the activated group was only 64 days,which was 333 d shorter than that in the non-activated group Ⅱ.The biodegradation rate of alkanes remained high for a long time,and the biodegradation rates at each stage were 14.23%(0-20 d),17.93%(20-40 d)and 15.73%(40-60 d),respectively.The degradation of alkanes in every 20 d maintained above 1500 mg/kg.However,the biodegradation rates of alkanes in the other three groups decreased significantly over time,and the highest degradation rate of alkanes was only 5.50% at 40-60 d.The fluorescence standard integration volumes of humic-like and fulvic-like acids in the soil after pre-oxidation were 2.80 and 3.82 times higher than those before soil pre-oxidation,respectively,which promoted the rapid growth of soil microorganisms.After adding acetic acid and glucose,the soil microorganisms were activated,and the activator utilization rates reached 88.06% and 91.38%,respectively.The soil microbial respiration activity remained above 5.00 mol/kg,while the non-activated group had a maximum of only 2.12 mol/kg at 40-60 d.In addition,the number of petroleum degrading bacteria in the activated group exceeded 9.00 lg(CFU/g)in the later stage,forming five dominant genera:Bacillus,Pseudomonas,Microbacterium,Streptomyces,and Hydrogenophaga,while the non-activated group had at most three dominant genera.The study indicated that the long-term degradation of alkanes in soil by microorganisms was mainly driven by their respiratory activity,abundance of petroleum-degrading bacteria,dominant genera number,and nutrient utilization rate.The research results provide an economical and effective method for solving the problem of soil petroleum pollution.