Shaw Environmental Inc., Lawrenceville, NJ 08648, USA.
Chemosphere. 2010 Nov;81(9):1111-7. doi: 10.1016/j.chemosphere.2010.09.002. Epub 2010 Sep 27.
Biologically produced iso-butanol is currently being considered as an additive in gasoline blends. To evaluate its potential environmental fate in groundwater aquifers, a laboratory microcosm study was performed to evaluate iso-butanol biodegradation under various anaerobic conditions (nitrate-reducing, sulfate-reducing and methanogenic). The impacts of iso-butanol on benzene, toluene, ethylbenzene, and total xylenes (BTEX) biodegradation were also assessed, and microcosms prepared using ethanol instead of iso-butanol were evaluated to provide a basis for comparison. Iso-butanol was biodegraded under all conditions studied, with an observed apparent first-order rate constant ranging from approximately 0.2 d⁻¹ (nitrate-reducing) to approximately 0.02 d⁻¹ (sulfate-reducing). Iso-butanol typically was degraded in a time frame that was shorter than or similar to BTEX compounds. Iso-butyric acid and trace levels of iso-butylaldehyde were identified as transient intermediates, and both of these compounds were subsequently degraded within the time frame of the experiments. Iso-butanol and ethanol were biodegraded in similar time frames under methanogenic conditions. Under sulfate-reducing conditions, iso-butanol biodegradation initially proceeded more slowly than ethanol, and then increased to a rate greater than that observed for ethanol; this observation likely was due to the growth of iso-butanol degrading bacteria. Iso-butanol generally exhibited less adverse impacts on BTEX biodegradations than ethanol under the anaerobic conditions studied. In some cases, addition of iso-butanol enhanced the rate of TEX biodegradation.
目前，生物合成的异丁醇正被视为汽油混合物的添加剂。为了评估其在地下水含水层中的潜在环境归宿，进行了一项实验室微宇宙研究，以评估在各种厌氧条件（硝酸盐还原、硫酸盐还原和产甲烷）下异丁醇的生物降解情况。还评估了异丁醇对苯、甲苯、乙苯和总二甲苯（BTEX）生物降解的影响，并评估了使用乙醇而不是异丁醇制备的微宇宙，以提供比较的基础。在所有研究的条件下，异丁醇都被生物降解，观察到的表观一级速率常数范围约为 0.2 d⁻¹（硝酸盐还原）至约 0.02 d⁻¹（硫酸盐还原）。异丁醇通常在比 BTEX 化合物更短或相似的时间内降解。异丁酸和痕量的异丁醛被鉴定为瞬态中间体，这两种化合物随后在实验的时间范围内被降解。在产甲烷条件下，异丁醇和乙醇在相似的时间内被生物降解。在硫酸盐还原条件下，异丁醇的生物降解最初比乙醇慢，但随后增加到比乙醇观察到的速率更快；这种观察结果可能是由于异丁醇降解细菌的生长。与研究的厌氧条件下的乙醇相比，异丁醇通常对 BTEX 生物降解的不利影响较小。在某些情况下，添加异丁醇会提高 TEX 生物降解的速率。
