异化金属还原菌的富集及降解有机药物的研究

Enrichment of Dissimilatory Metal-reducing Bacteria for Degradation of Organic Drugs

异化金属还原菌广泛存在于海底和河流等沉积物中,与水环境中各类有机物的迁移转化息息相关。但是目前关于异化金属还原菌降解难降解有机药物的研究相对匮乏,故选取嘉陵江磁器口河段三个不同取样点的河底沉积物(A、B、C)进行异化金属还原菌的富集培养,结果表明,三种沉积物均能够以合成铁氧化物悬浮液(Fe_(s))、合成锰氧化物悬浮液(Mn_(s))、赤铁矿粉末(Fe_(p))、二氧化锰粉末(Mn_(p))作为电子受体富集得到异化金属还原菌,通过7 d的富集培养OD_(600)能达到0.26~1.64。沉积物A以Mn_(s)作为电子受体时,可取得最佳的富集培养效果。富集菌液对初始浓度分别为1.72和1.52 mg/L的两种难降解混合有机药物卡马西平(CBZ)和双氯芬酸(DCF)的最大去除率能够达到48.92%和51.18%,这与异化金属还原纯菌GS-15对CBZ和DCF的去除率相差不大(分别为61.43%和66.74%)。

Dissimilatory metal-reducing bacteria are widely distributed in seabed and river sediments and are closely related to the migration and transformation of various organic substances in the water environment.However,there are relatively few studies on the degradation of refractory organic drugs by dissimilatory metal-reducing bacteria.Therefore,the sediments(A,B and C)from three different sampling sites in Ciqikou section of Jialing River were selected for the enrichment and cultivation of dissimilatory metalreducing bacteria.The dissimilatory metal-reducing bacteria could be enriched in the three sediments by using synthetic iron oxide suspension(Fe_(s)),synthetic manganese oxide suspension(Mn_(s)),hematite powder(Fe_(p)),manganese dioxide powder(Mn_(p))as the electron acceptors,and the OD_(600) reached 0.26-1.64 after 7 days of enrichment.When the Mn_(s) was used as the electron acceptor in the sediment A,the best enrichment effect was obtained.The maximum removal efficiencies of the two refractory mixed organic drugs[carbamazepine(CBZ)and diclofenac(DCF)]with the initial concentrations of 1.72 mg/L and 1.52 mg/L by the bacteria solution reached 48.92%and 51.18%,respectively,which were similar to the removal efficiencies of CBZ and DCF by GS-15 pure dissimilatory metal-reducing bacteria(61.43%and 66.74%,respectively).