Department of Earth and Environmental Sciences, Korea University, Seoul, 136-701, Republic of Korea.
Appl Biochem Biotechnol. 2013 May;170(2):248-56. doi: 10.1007/s12010-013-0176-4. Epub 2013 Mar 16.
In this study, we investigated the impact of nitrate dose on toluene degradation by Pseudomonas putida to elucidate the upper limit of nitrate concentration and whether an optimum ratio of nitrate to toluene concentration exists. Batch microcosm studies were conducted in order to monitor toluene degradation for various ratios (2-20) of nitrate to toluene with nitrate concentrations ranging from 0 to 700 mg L(-1) for a given toluene concentration of 50 and 25 mg L(-1) during 4-day (short term) and 14-day (long term) incubation time, respectively. The short-term study revealed that nitrate concentration of 500 mg L(-1) was toxic to bacteria and the optimum concentration was 300 mg L(-1) yielding the highest toluene degradation rate (0.083 mg L(-1) h(-1)). In the batch study of long term, toluene degradation was limited to 6 days after which the nitrate at 50 mg L(-1) was depleted, indicating that nitrate was a necessary electron acceptor. For both batch studies, an optimum ratio of 6 was found yielding the highest toluene degradation rate. This indicates that an appropriate nitrate dose is essential for efficient degradation of toluene when bioremediation of groundwater contaminated with toluene is under consideration.
在这项研究中，我们研究了硝酸盐剂量对假单胞菌降解甲苯的影响，以阐明硝酸盐浓度的上限以及是否存在硝酸盐与甲苯浓度的最佳比例。进行了批量微宇宙研究，以监测不同硝酸盐与甲苯比例（2-20）下的甲苯降解情况，硝酸盐浓度范围为 0 至 700mg/L，甲苯浓度分别为 50 和 25mg/L，短期（4 天）和长期（14 天）孵育时间分别为 4 天和 14 天。短期研究表明，500mg/L 的硝酸盐对细菌有毒，最佳浓度为 300mg/L，甲苯降解率最高（0.083mg/L/h）。在长期批量研究中，甲苯降解在 6 天后受到限制，此时 50mg/L 的硝酸盐被耗尽，表明硝酸盐是必需的电子受体。对于这两个批量研究，都发现最佳比例为 6，甲苯降解率最高。这表明在考虑生物修复受甲苯污染的地下水时，适当的硝酸盐剂量对于高效降解甲苯是必不可少的。
