Isolation and Growth Characteristics of an EDTA-degrading Member of the α-subclass of Proteobacteria
Isolation and Growth Characteristics of an EDTA-degrading Member of the α-subclass of Proteobacteria
复制标题
变形菌门 α 亚类 EDTA 降解成员的分离和生长特性
作者：
H. Weilenmann;Barbara E Engeli;M. Bucheli;T. Egli
利用EDTA作为碳、能量和氮的唯一来源的革兰氏阴性乙二胺四乙酸（EDTA）降解细菌（保藏在德国培养物保藏中心，保藏号为DSM 9103）从最初富集在柱系统中的活性污泥和土壤的混合物中的混合EDTA降解菌群中分离。醌类、极性脂质和脂肪酸的化学分类学分析允许将分离物分配到变形菌门的α-亚类。16 S rDNA序列分析和系统发育分析表明，最高的相似性Mesorhizobium属其次是Aminobium属。然而，EDTA降解菌株显然在叶杆菌科/中慢根瘤菌科中形成了一个新的分支。该菌株不仅在EDTA（μmax=0.05h−1）上生长相当缓慢，在其他底物上也是如此。经典的底物利用率在分批培养测试表明，一个非常有限的碳源光谱，只有乳酸盐，谷氨酸盐，和络合剂化学相关的EDTA（次氮基三乙酸，亚氨基二乙酸和乙二胺二琥珀酸盐）支持的增长。然而，当用富马酸盐、琥珀酸盐、葡萄糖或乙酸盐脉冲处理菌株DSM 9103的EDTA限制的连续培养物时，这些底物立即被同化。显然，该菌株可以使用比传统底物测试技术所指示的更宽的光谱。EDTA种类CaEDTA和MgEDTA充当菌株的生长底物，因为在所用的矿物培养基中，预测EDTA主要以这两种络合物的形式存在。该细菌无法降解Fe 3+络合的EDTA。
A Gram-negative, ethylenediaminetetraacetic acid (EDTA)-degrading bacterium (deposited at the German Culture Collection as strain DSM 9103) utilising EDTA as the only source of carbon, energy and nitrogen was isolated from a mixed EDTA-degrading population that was originally enriched in a column system from a mixture of activated sludge and soil. Chemotaxonomic analysis of quinones, polar lipids and fatty acids allowed allocation of the isolate to the α-subclass of Proteobacteria. 16S rDNA sequencing and phylogenetic analysis revealed highest similarity to the Mesorhizobium genus followed by the Aminobacter genus. However, the EDTA-degrading strain apparently forms a new branch within the Phyllobacteriaceae/Mesorhizobia family. Growth of the strain was rather slow not only on EDTA (μmax=0.05h−1) but also on other substrates. Classical substrate utilisation testing in batch culture suggested a quite restricted carbon source spectrum with only lactate, glutamate, and complexing agents chemically related to EDTA (nitrilotriacetate, iminodiacetate and ethylenediaminedisuccinate) supporting growth. However, when EDTA-limited continuous cultures of strain DSM 9103 were pulsed with fumarate, succinate, glucose or acetate, these substrates were assimilated immediately. Apparently, the strain can use a broader spectrum than indicated by traditional substrate testing techniques. The EDTA species CaEDTA and MgEDTA served as growth substrates of the strain because in the mineral medium employed EDTA was predicted to be mainly present in the form of these two complexes. The bacterium was not able to degrade Fe3+-complexed EDTA.