恶臭假单胞菌Pseudomonas putida 5-x细胞壁膜系统的Cu2+吸附性能

对1株从电镀废水中分离出的革兰氏阴性菌恶臭假单胞菌P.putida 5-x的细胞表面组分对Cu²⁺的吸附性能进行了分析研究.结果表明,分离的P.putida 5-x细胞壁膜的Cu²⁺吸附容量是完整细胞的5倍之多.细胞表面组分如肽聚糖层、细胞外膜和细胞内膜在P.putida 5-x细胞壁膜的Cu²⁺吸附过程中都发挥了作用.肽聚糖层、细胞外膜和内膜在P.putida 5-x细胞壁膜中的含量依次为细胞内膜>外膜>肽聚糖层,而它们的Cu²⁺吸附容量的大小依次为肽聚糖层>外膜>内膜.在P.putida 5-x细胞壁膜对Cu²⁺的吸附过程中,肽聚糖层贡献了不到15%的吸附容量,而细胞外膜和内膜分别贡献了30%～35%和25%～30%.P.putida 5-x细胞外膜中的磷脂含量明显比其它报道的革兰氏阴性细菌的细胞外膜高,这可能是P.putida 5-x细胞外膜具有较高Cu²⁺吸附容量的主要原因,并由此导致P.putida 5-x细胞壁膜的高Cu2+吸附容量.

Capability of Cu2+ Adsorption on Cell Surface of Pseudomonas putida 5-x

Analysis of Cu2+ adsorption on cell surface of a Gram-negative bacterium P. putida 5-x was carried out. Isolated cell envelopes possess fivefold more Cu2+ adsorption capacity than that of the fresh intact cells. Experimental results also indicate that the content of the peptidoglycan layer, the outer membrane and inner membrane in the cell envelope is in order of inner membrane > outer membrane > PEG layer, while their Cu2+ adsorption capacity is in order of PEG layer > outer membrane > inner membrane. The total contribution of the separated PEG layer material to Cu2+ adsorption is no more than 15% part, and the cell outer membrane and inner membrane contribute about 30%-35% and 25%-30% part, respectively, to Cu2+ adsorption by the cell envelope. The relatively high phospholipid content in the outer wall might result in its higher adsorption capacity to Cu2+, and leads to a higher adsorption capacity of the cell envelope of P. putida 5-x.