CAJ | 학술논문

运用超声波结合离心方法提取Acidithiobacillus.ferrooxidans的胞外多聚物(EPS),用2-酮基-3-脱氧辛酸(KDO)作为表征EPS含量的指标,采用分光光度法对该提取方法进行评估.通过一系列对比性实验研究EPS对Acidithiobacillus ferrooxidans在黄铜矿与黄铁矿表面吸附的影响.将未处理的Acidithiobacillus ferrooxidans与经处理脱去EPS层的Acidithiobacillus ferrooxidans分别与EPS悬液、Fe2+和Fe3+重新混合,在2h的反应过程中,实时检测混合液中游离的细菌含量.结果表明:细菌表面EPS的存在是其吸附于黄铁矿和黄铜矿表面的一个重要因素.当缺失EPS层时,Acidithiobacillus ferrooxidans吸附于矿物表面的能力有所下降,但当重新加入EPS混合液时这种能力能大部分恢复,这种恢复程度在黄铁矿中较黄铜矿中更加明显.当加入EPS和Fe3+时其细菌吸附于黄铜矿表面的程度有所升高,而加入Fe2+时吸附程度明显降低,这个结果表明静电的相互作用也许是细菌最初吸附于矿物表面的一个主要原因,并且这也许是细菌生产EPS的一种驱动力以使细菌吸附于硫化铜矿物后重新获得其吸附能力.
운용초성파결합리심방법제취Acidithiobacillus.ferrooxidans적포외다취물(EPS),용2-동기-3-탈양신산(KDO)작위표정EPS함량적지표,채용분광광도법대해제취방법진행평고.통과일계렬대비성실험연구EPS대Acidithiobacillus ferrooxidans재황동광여황철광표면흡부적영향.장미처리적Acidithiobacillus ferrooxidans여경처리탈거EPS층적Acidithiobacillus ferrooxidans분별여EPS현액、Fe2+화Fe3+중신혼합,재2h적반응과정중,실시검측혼합액중유리적세균함량.결과표명:세균표면EPS적존재시기흡부우황철광화황동광표면적일개중요인소.당결실EPS층시,Acidithiobacillus ferrooxidans흡부우광물표면적능력유소하강,단당중신가입EPS혼합액시저충능력능대부분회복,저충회복정도재황철광중교황동광중경가명현.당가입EPS화Fe3+시기세균흡부우황동광표면적정도유소승고,이가입Fe2+시흡부정도명현강저,저개결과표명정전적상호작용야허시세균최초흡부우광물표면적일개주요원인,병차저야허시세균생산EPS적일충구동력이사세균흡부우류화동광물후중신획득기흡부능력.
Extracellular polymeric substances (EPS) were extracted from Acidithiobacillusferrooxidans through sonication method associated with centrifugation,which was evaluated tentatively with 2-keto-3-deoxyoctonic acid (KDO) as the indicator of EPS by spectrophotometry.Then the effect of EPS of A.ferrooxidans on the adhesion on chalcopyrite and pyrite surfaces was studied through a series of comparative experiments.The untreated cells and EPS-free cells of A.ferrooxidans were mixed with EPS suspension,Fe2+ or Fe3+,respectively.The planktonic cells were monitored in 2 h during bioleaching.The results indicate that the presence of EPS on the cell is an important factor for the adhesion to chalcopyrite and pyrite.A decrease of attachment of A.ferrooxidans to minerals was produced by the deficiency of EPS,which can recover mostly when the EPS was re-added into the EPS-free cells.The restoring extent is more obvious in pyrite than in chalcopyrite.The extent of cell adhesion to chalcopyrite increased when EPS and Fe3+ added,and decreased when Fe2+ added,which imply the electrostatic interaction plays a main role in initial adhesion between bacteria and minerals and it is a driving force for bacteria to produce EPS probably as a result of regaining their attachment ability to copper sulphides.