六六六(HCH)降解菌Sphingomonassp.BHC-A的分离与降解特性的研究

Isolation and characterization of a HCH degradation Sphingomanas sp. stain BHC-A

从长期受六六六污染的土壤中分离得到一株能以HCH为唯一碳源的高效降解菌株BHC-A。通过对其主要生理生化特征分析,以及16S rDNA序列的测定和同源性比较分析,将BHC-A鉴定为鞘氨醇单胞菌属(Sphingomonassp.)。BHC-A菌株在12h以内能够完全矿化浓度分别为5mg/L的α-、β-、γ-、δ-HCH4种异构体,特别是对β-HCH的降解在国际上也属少例。而前人所报道的γ-HCH降解菌Sphingomonas paucimobilisUT26菌株对β-HCH和δ-HCH不产生降解作用,即使经过24h的培养,对5mg/L的α-HCH的降解率也只有12.6%。在黄瓜的盆钵试验中发现,15d后BHC-A在土壤中对α、β-、γ-、δ-HCH4种异构体的降解率为84.3%,能够有效地消除土壤中六六六的污染,缓解植株受药害症状。

An aerobic bacterium was isolated successfully from a long-term contaminated upland field, which was named BHC-A. The bacterium can utilize Hexachlorocycloexane as a sole carbon source and decompose this substance rapidly and completely. According to its physiological ＆ biochemical characters and the homology analysis of its 16S rDNA sequence, this strain was identified as Sphingomonas sp. Stain BHC-A canmineralize not only α,γ and δ-HCH rapidly, but also 5 mg/L β-HCH in 12h completely. However, Sphingomonas paucimobilis UT26, α γ-HCH-decomposing bacterium, can only degrade 12.6% of 5 mg/L α-HCH, but not β-HCH and δ-HCH, even for more than 24h in the medium. The seedling of cucumber was selected as the model plant subject to the inhibition of HCH to the growth of cucurbitaceous plants. The results shows that the degradation of HCH isomers by BHC-A in soil is even steady and excellent, that BHC-A can eliminate the contamination of the soil and the harm to the plants.