Assessment of biofilm changes and concentration-depth profiles during arsenopyrite oxidation by Acidithiobacillus thiooxidans

作者：Ramirez Aldaba Hugo; Vazquez Arenas Jorge; Sosa Rodriguez Fabiola S; Valdez Perez Donato; Ruiz Baca Estela; Viridiana Garcia Meza Jessica; Trejo Cordova Gabriel; Lara Rene H^*

来源：Environmental Science and Pollution Research, 2017, 24(24): 20082-20092.

DOI：10.1007/s11356-017-9619-8

• Arsenopyrite biooxidation
• Acidithiobacillus thiooxidans
• Biofilmchanges
• Glow discharge spectroscopy
• Surface analysis

Biofilm formation and evolution are key factors to consider to better understand the kinetics of arsenopyrite biooxidation. Chemical and surface analyses were carried out using Raman spectroscopy, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS), and protein analysis (i.e., quantification) in order to evaluate the formation of intermediate secondary compounds and any significant changes arising in the biofilm structure of Acidithiobacillus thiooxidans during a 120-h period of biooxidation. Results show that the biofilm first evolves from a low cell density structure (1 to 12 h) into a formation of microcolonies (24 to 120 h) and then finally becomes enclosed by a secondary compound matrix that includes pyrite (FeS2)-like, S (n) (2-)/S-0, and As2S3 compounds, as shown by Raman and SEM-EDS. GDS analyses (concentration-depth profiles, i.e., 12 h) indicate significant differences for depth speciation between abiotic control and biooxidized surfaces, thus providing a quantitative assessment of surface-bulk changes across samples (i.e. reactivity and /or structure-activity relationship). Respectively, quantitative protein analyses and CLSM analyses suggest variations in the type of extracellular protein expressed and changes in the biofilm structure from hydrophilic (i.e., exopolysaccharides) to hydrophobic (i.e., lipids) due to arsenopyrite and cell interactions during the 120-h period of biooxidation. We suggest feasible environmental and industrial implications for arsenopyrite biooxidation based on the findings of this study.

• 出版日期2017-8