Leakage of cellular material from Thiobacillus ferrooxidans in the presence of organic acids

Acidithiobacillus caldus is a thermophilic acidophile found in commercial biomining, acid mine drainage systems, and natural environments. Previous work has characterized A. caldus as a chemolithotrophic autotroph capable of utilizing reduced sulfur compounds under aerobic conditions. Organic acids are especially toxic to chemolithotrophs in low-pH environments, where they diffuse more readily into the cell and deprotonate within the cytoplasm. In the present study, the toxic effects of oxaloacetate, pyruvate, 2-ketoglutarate, acetate, malate, succinate, and fumarate on A. caldus strain BC13 were examined under batch conditions. All tested organic acids exhibited some inhibitory effect. Oxaloacetate was observed to inhibit growth completely at a concentration of 250 microM, whereas other organic acids were completely inhibitory at concentrations of between 1,000 and 5,000 microM. In these experiments, the measured concentrations of organic acids decreased with time, indicating uptake or assimilation by the cells. Phospholipid fatty acid analyses indicated an effect of organic acids on the cellular envelope. Notable differences included an increase in cyclic fatty acids in the presence of organic acids, indicating possible instability of the cellular envelope. This was supported by field emission scanning-electron micrographs showing blebbing and sluffing in cells grown in the presence of organic acids.

show abstract

“…6). This has been observed previously using microscopy with A. ferrooxidans grown in the presence of organic acids [13].…”

Section: Plfa Analysis and Cell Imagingsupporting

confidence: 80%

Toxicity of select organic acids to the slightly thermophilic acidophile Acidithiobacillus caldus

Aston

Lee

Peyton

2009

Enviro Toxic and Chemistry

View full text Add to dashboard Cite

show abstract

“…However, membrane damage has previously been reported in bacteria after exposure to organic acid. Tuttle et al (1977) observed membrane blebbing after exposing Thiobacillus ferroodoxans to butanoic acid. Sannasiddappa thus the possibility that butanoic acid induces a similar response in A. baumannii and S. pseudintermedius cannot be discounted.…”

Section: Discussionmentioning

confidence: 88%

Inactivation of the bacterial pathogens Staphylococcus pseudintermedius and Acinetobacter baumannii by butanoic acid

et al. 2019

View full text Add to dashboard Cite

Aims This study was performed to evaluate the efficacy of butanoic acid against bacterial pathogens including Acinetobacter baumannii and Staphylococcus pseudintermedius. Methods and Results Vegetative bacteria were exposed to butanoic acid in vitro and log reduction was quantified using viable count assays. The maximum (8 and 9) log inactivation was determined by qualitatively assaying for growth/no‐growth after a 48‐h incubation (37°C). Membrane integrity after exposure to butanoic acid was determined by propidium iodide staining, scanning electron microscopy, membrane depolarization and inductively coupled plasma analysis. Cytosolic pH was measured by 5‐(6‐)carboxyfluorescein succinimidyl ester. Conclusions Inhibitory concentrations of butanoic acid ranged between 11 and 21 mmol l−1 for Gram‐positive and Gram‐negative species tested. The maximum log reduction of A. baumannii was achieved with a 10‐s exposure of 0·50 mol l−1 of butanoic acid. Staphylococcus pseudintermedius required 0·40 mol l−1 of butanoic acid to achieve the same level of reduction in the same time period. Inactivation was associated with membrane permeability and acidification of the cytosol. Significance and Impact of the Study Antibiotic resistance among bacterial pathogens necessitates the utilization of novel therapeutics for disinfection and biological control. These results may facilitate the development of butanoic acid as an effective agent against a broad‐spectrum of antibiotic‐resistant bacterial pathogens.

show abstract

“…Indeed, we always observe the extracellular carbon in concentrated cultures of T. ferrooxidans to be between 15 and 22% of the total acid-stable carbon. The leakage of cellular material from T. ferrooxidans in the presence of organic acids has been documented (34). If such leakage or cell lysis were the principal source of the cell-free organic material in this case, one might anticipate that the percentage of extracellular carbon would not remain constant.…”

Section: Fig 5 In Situ Electrolytic Cultivation Of T Ferrooxidans mentioning

confidence: 99%

Enhanced Yields of Iron-Oxidizing Bacteria by In Situ Electrochemical Reduction of Soluble Iron in the Growth Medium

Blake

Howard

McGinness

1994

Appl Environ Microbiol

View full text Add to dashboard Cite

An electrochemical apparatus for culturing chemolithotrophic bacteria that respire aerobically on ferrous ions is described. Enhanced yields of the bacteria were achieved by the in situ electrochemical reduction of soluble iron in the growth medium. When subjected to a direct current of 30 A for 60 days, a 45-liter culture of Thiobacillus ferrooxidans grew from 6 x 107 to 9.5 x 109 cells per ml. Growth of the bacterium within the electrolytic bioreactor was linear with time. A final cell density corresponding to 4.7 g of wet cell paste per liter was achieved, and a total of 320 g of wet cell paste was harvested from one culture. The apparatus was designed to deliver protons concomitantly with electrons; therefore, the pH of the culture remained stable at 1.6 ± 0.1 for the duration of growth. This laboratory-scale apparatus may be readily adapted to pilot or production scale. It is thus anticipated that abundant numbers of iron-oxidizing bacteria may be obtained for both fundamental and applied studies.

show abstract

Leakage of cellular material from Thiobacillus ferrooxidans in the presence of organic acids

Cited by 41 publications

References 34 publications

Toxicity of select organic acids to the slightly thermophilic acidophile Acidithiobacillus caldus

Toxicity of select organic acids to the slightly thermophilic acidophile Acidithiobacillus caldus

Inactivation of the bacterial pathogens Staphylococcus pseudintermedius and Acinetobacter baumannii by butanoic acid

Enhanced Yields of Iron-Oxidizing Bacteria by In Situ Electrochemical Reduction of Soluble Iron in the Growth Medium

Contact Info

Product

Resources

About