甲苯对土壤芳基硫酸酯酶活性的影响

甲苯作为土壤酶测定的前处理试剂及许多有机污染物在环境中降解的中间产物,有关其对土壤酶的影响研究在土壤酶学和环境科学领域具有重要意义.因此,采用模拟方法,较系统地研究了不同剂量甲苯和处理时间下芳基硫酸酯酶活性的变化规律.结果表明,甲苯对纯酶具有明显的抑制作用,酶活性降幅最大达到45.5%;灭菌土壤对溶液中的纯酶有很强的吸附能力;极微量的甲苯即可完成对土壤中酶活性的激活作用,酶活性增幅为109%～298%;随着甲苯剂量的增加,土壤酶活性的变化幅度逐渐趋缓,并可用Langmuir模型较好地拟合,由此获得了最大表观酶活性Umax,发现其与土壤性质显著相关,说明甲苯主要是通过杀死土壤中的微生物来影响土壤酶活性的.此外,初步探讨了不同土壤中胞外酶量与胞内酶量的关系,发现在供试土样中土壤芳香硫酸酯酶胞外酶和胞内酶分别占54.4%和45.6%.本研究可为后续土壤酶测定质量的完善和提高提供依据.

Effect of toluene on arylsulfatase activity in soil

Toluene is the pre-treatment reagent for assaying soil enzymes, and is one of the intermediates of many organic pollutants that are degraded in the environment. The research of toluene affecting soil enzyme has great significance in soil enzymology and environmental science. Therefore, by simulation methods,the variation of pure and soil arylsulfatase activity affected by toluene with different concentrations and time were studied systematically. The results showed that toluene inhibited the pure arylsulfatase significantly, with the largest decrement in activity as 45.5%. The sterilized soil had great ability to absorb pure enzyme in solution. Very trace toluene could increase the soil enzyme activity greatly, with the increasing variation of 109%~298% as that without toluene treatment. With further increasing toluene concentration, soil enzyme activity kept increasing but with a slower rate. Langmuir equation could fit the variation of soil enzyme activity well, and the maximum activity can be thus obtained which was significantly correlated with soil properties. It was revealed that toluene affected soil enzyme activity mostly by killing the soil microorganism. In tested soil sample, the extracellular and intracellular soil arylsulfatase activity was 54.4% and 45.6% on average, respectively. The results provided scientific support for improving the quality of soil enzyme assay.