Characterization of Ferroplasma acidiphilum growing in pure and mixed culture with Leptospirillum ferriphilum

Abstract

Biomining is defined as biotechnology for metal recovery from minerals, and is promoted by the concerted effort of a consortium of acidophile prokaryotes, comprised of members of the Bacteria and Archaea domains. Ferroplasma acidiphilum and Leptospirillum ferriphilum are the dominant species in extremely acid environments and have great use in bioleaching applications; however, the role of each species in this consortia is still a subject of research. The hypothesis of this work is that F. acidiphilum uses the organic matter secreted by L. ferriphilum for growth, maintaining low levels of organic compounds in the culture medium, preventing their toxic effects on L. ferriphilum. To test this hypothesis, a characterization of Ferroplasma acidiphilum strain BRL-115 was made with the objective of determining its optimal growth conditions. Subsequently, under the optimal conditions, L. ferriphilum and F. acidiphilum were tested growing in each other's supernatant, in order to define if there was exchange of metabolites between the species. With these results, a mixed culture in batch cyclic operation was performed to obtain main specific growth rates, which were used to evaluate a mixed metabolic model previously developed by our group. It was observed that F. acidiphilum, strain BRL-115 is a chemomixotrophic organism, and its growth is maximized with yeast extract at a concentration of 0.04% wt/vol. From the experiments of L. ferriphilum growing on F. acidiphilum supernatant and vice versa, it was observed that in both cases cell growth is favorably affected by the presence of the filtered medium of the other microorganism, proving a synergistic interaction between these species. Specific growth rates were obtained in cyclic batch operation of the mixed culture and were used as input data for a Flux Balance Analysis of the mixed metabolic model, obtaining a reasonable behavior of the metabolic fluxes and the system as a whole, therefore consolidating the model previously developed. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1390-1396, 2016.

Distinct Roles of Acidophiles in Complete Oxidation of High-Sulfur Ferric Leach Product of Zinc Sulfide Concentrate

“…A similar pattern of synergistic interaction between F. acidiphilum and L. ferriphilum was also observed [58]. The growth of chemomixotrophic F. acidiphilum was favored by the supernatant of chemolithoautotrophic L. ferriphilum, containing additional sources of the organic carbon (EPS and lysed cells) and vice versa, probably due to detoxification of the medium from organic compounds by mixotrophic F. acidiphilum and extracellular proteins of its "secretome" [58]. The study of the microbial community dynamics in various industrial processes of tank or heap biooxidation showed the dominance of the Ferroplasmaceae family members [59][60][61].…”

“…Acidiphilum acidophilum was able to increase the efficiency of metal bioleaching due to the utilization of organic substances, therefore decreasing the toxicity of the culture medium for autotrophic acidophiles [57]. A similar pattern of synergistic interaction between F. acidiphilum and L. ferriphilum was also observed [58]. The growth of chemomixotrophic F. acidiphilum was favored by the supernatant of chemolithoautotrophic L. ferriphilum, containing additional sources of the organic carbon (EPS and lysed cells) and vice versa, probably due to detoxification of the medium from organic compounds by mixotrophic F. acidiphilum and extracellular proteins of its "secretome" [58].…”

Advances in the development and application of microbial consortia for metabolic engineering

“…acid mine drainage (Merino et al., 2015). This symbiotic association helps in oxidizing iron and sulfur containing minerals (Merino et al., 2016, 2015). A metabolic model for a mixed culture composed of L. ferriphilum and F. acidiphilum was reconstructed for deeper understanding of the metabolism of these microorganisms growing together (Merino et al., 2015).…”

“…A metabolic model for a mixed culture composed of L. ferriphilum and F. acidiphilum was reconstructed for deeper understanding of the metabolism of these microorganisms growing together (Merino et al., 2015). Further validation of the model revealed that F. acidiphilum utilizes the organic matter secreted by L. ferriphilum for growth, maintaining low levels of organic compounds in the culture medium and preventing their toxic effects on L. ferriphilum (Merino et al., 2016).…”

Procesos de remediación y recuperación de metales pesados utilizando comunidades microbianas extremófilas

“…La comunidad AL original y los consorcios litótrofos acidófilos resistentes obtenidos a partir de ella tuvieron al género Acidithiobacillus (representado principalmente por el ASV 6) como dominante, con la excepción del consorcio resistente a cobre en el que predominó Ferroplasma (ASV 3), éste también fue dominante en el consorcio no expuesto y estuvo presente en el consorcio resistente a níquel. La presencia de Acidithiobacillus en ambientes acidófilos y de alta carga metálica es ampliamente conocida (Huang et al, 2016;Nuñez et al, 2016Nuñez et al, , 2017; de igual manera, las arqueas del género Ferroplasma también han sido reportadas en ambientes similares y su resistencia a cobre ha sido aprovechada para el desarrollo de procesos de biolixiviación de sulfuros minerales cuprosos como la calcopirita y la calcosina (Golyshina et al, 2000;Dopson et al, 2004;Golyshina & Timmis, 2005;Hawkes et al, 2006;Zhou et al, 2008;Merino et al, 2016).…”