Kobayashi Takayuki, Murai Yasushi, Tatsumi Kenji, Iimura Yosuke
National Institute of Advanced Industrial Science and Technology (AIST), 16-1, Onogawa, Tsukuba, Ibaraki 305-8506, Japan.
Sci Total Environ. 2009 Nov 1;407(22):5805-10. doi: 10.1016/j.scitotenv.2009.06.041. Epub 2009 Aug 5.
The effectiveness of in-situ bioremediation of polycyclic aromatic hydrocarbons (PAHs) may be inhibited by their low aqueous solubility and strong absorption to soil constituents. The aim of this research was to evaluate the effect of water-extractable organic matter (WEOM) from manure compost on the biodegradation of various PAHs. The aqueous solubilities of PAHs including phenanthrene, pyrene and benzo[a]pyrene under different concentrations of WEOM from cow manure compost were initially evaluated. The contribution of WEOM on the degradation of PAHs by Sphingomonas sp. was then investigated. Dissolution results confirmed the ability of WEOM to increase the apparent solubility of the 3PAHs. Time course of biodegradation also revealed its positive contribution to their removal. For example, the degradation of pyrene was 118% higher in the presence of 1000 mg-C L(-1) WEOM as compared to the mineral salt medium (MSM) alone after 48 h incubation. In addition, degradation was 12% higher with WEOM than with Glucose-Ammonium nitrate despite the more than 6 times higher cell concentration in the latter. WEOM from other manure composts such as chicken and pig were found to have the same effect. Finally, additional tests confirmed that high molecular weight WEOM (>1000 Da) contributed mainly to solubility and biodegradation enhancements. On the basis of these results, the increase in apparent solubility of PAHs in WEOM solutions may have a significant impact on their biodegradation. It is postulated that the application of WEOM-rich manure composts may be extended in the in-situ bioremediation of PAHs-polluted soil.
多环芳烃（PAHs）的原位生物修复效果可能会因其在水中的低溶解度以及对土壤成分的强吸附性而受到抑制。本研究的目的是评估来自粪肥堆肥的水溶性有机物（WEOM）对各种PAHs生物降解的影响。首先评估了在不同浓度的牛粪堆肥WEOM下菲、芘和苯并[a]芘等PAHs的水溶性。然后研究了WEOM对鞘氨醇单胞菌属降解PAHs的贡献。溶解结果证实了WEOM增加3种PAHs表观溶解度的能力。生物降解的时间进程也揭示了其对PAHs去除的积极贡献。例如，在1000 mg-C L(-1) WEOM存在的情况下，培养48小时后芘的降解率比单独的无机盐培养基（MSM）高118%。此外，尽管后者的细胞浓度高出6倍多，但WEOM处理的降解率比葡萄糖-硝酸铵处理高12%。发现来自其他粪肥堆肥如鸡粪和猪粪的WEOM也有相同的效果。最后，额外的测试证实高分子量WEOM（>1000 Da）主要有助于提高溶解度和生物降解能力。基于这些结果，PAHs在WEOM溶液中表观溶解度的增加可能对其生物降解有重大影响。据推测，富含WEOM的粪肥堆肥在PAHs污染土壤的原位生物修复中的应用可能会得到推广。
