一株降解氯霉素电活性菌株的筛选及其电子传递路径OACSTPCD

Bioelectrochemical systems have attracted extensive attention in the field of environment and energy.Due to the degradation of pollutants and simultaneous generation of green electricity,bioelectrochemical process can provide an efficient method for the treatment of antibiotic-containing wastewater.In this study,a highly effective chloramphenicol(CAP)degrading strain DB-1,which was isolated from the anode effluent of a long-term operated microbial fuel cell(MFC),was identified and named as Raoultella sp DB-1 according to its morphological characteristics,physiological and biochemical characteristics,and 16S rRNA gene sequence.The CAP degradation rate reached 42.0％from initial concentration of 50.0 mg/L after strain DB-1 was cultured for 48 h in the medium with glucose as carbon source.During this bioelectrochemical process for strain DB-1,direct contact and cytochrome c served as the predominant extracellular electron transfer pathway,along with some assistance from the secretion of electron mediators.Furthermore,a typical two-chamber microbial fuel cell(MFC)was constructed with inoculation of strain DB-1 in the anode.Upon the acclimation of anode electroactive biofilm,the maximum output voltage of MFC reached(355.0±6.4)mV.With the increase of CAP concentration in anodic solution(10.0-80.0 mg/L),the output voltage of MFC showed an interesting trend with initial decrease,followed by increase then decrease again.However,the electroactive biofilm of strain DB-1 on the anode could gradually become resistant to CAP.In other words,the bioelectrochemical degradation rate of CAP gradually accelerated in the anode chamber.In conclusion,the strain Raoultella sp DB-1 identified in this study demonstrated dual effects,efficient degradation of CAP and simultaneous generation of electricity,suggesting such bioelectrochemical process could have potential application for the treatment of organic wastewater containing antibiotics.