Chao W L, Lin C M, Shiung I I, Kuo Y L
Department of Microbiology, Soochow University, 70 Lin Shi Road, Shih Lin, Taipei, Taiwan, ROC.
Chemosphere. 2006 May;63(8):1377-83. doi: 10.1016/j.chemosphere.2005.09.021. Epub 2005 Nov 14.
Twelve Gram-positive phthalate ester degraders were isolated from soil. Using Biolog GP2 plates, eight of them were identified as belonging to the Corynebacterium-Mycobacterium-Nocardia group, while the remaining four were unidentifiable. When cultured in the presence of di-butyl-phthalate (DBP) in basal salts solution, five of these isolates accomplished more than 90% of DBP degradation within 48 h (fast group), three were placed in the medium group, and the remaining four were placed in the slow group which caused less than 30% of DBP degradation within the same period of time. A 420 bp DNA fragment was amplified from six isolates and none of them fell within the slow group. When compared with the large subunit of phthalate dioxygenase gene (phtA) of Arthrobacter keyseri, 83% and 91% similarities were evident in the nucleotide and amino acid sequences, respectively. However, no correlation between cell surface hydrophobicity and phthalate degradation ability was evident. Six surfactants (Brij 30, Brij 35, Tergitoltype NP-10, Triton N-101, Triton X-100 and SDS) were tested for their abilities to increase degradation rate. When added at the critical micellar concentration (CMC), they all displayed strong growth inhibition against the three bacteria tested, with Brij 30 been the least toxic to isolates G2 and G11, and Brij 35 had the least inhibitory effect for G1. When half the CMC of Brij 30 was incorporated into the basal salts, the inhibitory effect on DBP degradation remained. Soil helped to minimize surfactant toxicity of surfactant and increase the degradation potential of some of the test bacteria. When DBP-amended soil had been aged for three months, decreases in bioavailability were observed but the effect varied tremendously between different organisms. For isolates G1, G2, G5, G7 and G17 the aging effects were almost non-exist. The present study indicates that selection of a suitable degrader may minimize the undesired effect of aging on bioremediation process.
从土壤中分离出12株革兰氏阳性邻苯二甲酸酯降解菌。使用Biolog GP2平板，其中8株被鉴定为属于棒杆菌-分枝杆菌-诺卡氏菌属，其余4株无法鉴定。当在基础盐溶液中于邻苯二甲酸二丁酯（DBP）存在下培养时，这些分离株中有5株在48小时内完成了超过90%的DBP降解（快速组），3株属于中等组，其余4株属于慢速组，在同一时间段内导致的DBP降解少于30%。从6株分离株中扩增出一个420 bp的DNA片段，且它们均不属于慢速组。与节杆菌的邻苯二甲酸双加氧酶基因（phtA）的大亚基相比，核苷酸和氨基酸序列的相似性分别为83%和91%。然而，细胞表面疏水性与邻苯二甲酸降解能力之间没有明显的相关性。测试了六种表面活性剂（Brij 30、Brij 35、Tergitol型NP-10、Triton N-101、Triton X-100和SDS）提高降解率的能力。当以临界胶束浓度（CMC）添加时，它们对所测试的三种细菌均表现出强烈的生长抑制作用，其中Brij 30对分离株G2和G11的毒性最小，Brij 35对G1的抑制作用最小。当将Brij 30的一半CMC加入基础盐中时，对DBP降解的抑制作用仍然存在。土壤有助于将表面活性剂的毒性降至最低，并提高一些测试细菌的降解潜力。当添加DBP的土壤老化三个月后，观察到生物可利用性降低，但不同生物体之间的影响差异极大。对于分离株G1、G2、G5、G7和G17，老化影响几乎不存在。本研究表明，选择合适的降解菌可将老化对生物修复过程的不良影响降至最低。
