Comparative analysis of early-stage adsorption and biofilm formation of thermoacidophilic archaeon Acidianus manzaensis YN-25 on chalcopyrite and pyrite surfaces

Abstract

The early-stage attachment behaviors of acidophiles on mineral surfaces and the subsequent biofilm formation play important roles in acid mine drainage production, and also can improve the leaching efficiency of metal sulfides. However, despite significant advances in correlational researches of mesophilic bacteria, studies on thermoacidophilic archaeon are still limited. In this study, the early attachment behaviors and biofilm formation of the thermoacidophilic archaeon Acidianus manzaensis YN-25 on chalcopyrite and pyrite were investigated. Experiments showed that A. manzaensis YN-25 attached quickly on chalcopyrite and pyrite within a short adsorption equilibrium time of about 20 min. After the adsorption equilibrium, the percentage of attached cells was higher on chalcopyrite than on pyrite (59 % versus 54 %). And the early-stage adsorption of Acidianus manzaensis YN-25 on chalcopyrite and pyrite surfaces was occurred through multilayer adsorption. Also, the measured adhesion forces (0.41 nN versus 0.31 nN) showed more affinity of A. manzaensis YN-25 to chalcopyrite than to pyrite. Furthermore, in the process of biofilm formation, more cells colonized on the chalcopyrite than pyrite, suggesting that the biofilm formation was positively correlated with the initial adhesion. Moreover, during the entire life cycle of A. manzaensis YN-25 biofilm, dead cells have accounted for a big proportion.