Thiobacillus acidophilus sp. nov.; isolation and some physiological characteristics

Area of Science:

• Microbiology
• Bacteriology
• Biochemistry

Background:

• Isolation of novel microorganisms is crucial for understanding microbial diversity.
• Thiobacillus species are known for their roles in sulfur oxidation and acid mine drainage.
• Characterization of new isolates provides insights into metabolic capabilities and ecological roles.

Purpose of the Study:

• To isolate and characterize a novel bacterium from an iron-grown culture.
• To determine the physiological and biochemical properties of the new isolate.
• To investigate the metabolic potential and energy sources of the bacterium.

Main Methods:

• Isolation of Thiobacillus acidophilus from T. ferrooxidans culture after glucose exposure.
• Physicochemical analysis of DNA for G+C content.
• Determination of optimal growth conditions (temperature, pH).
• Assessment of nitrogen sources and energy substrates.
• Enzyme assays for key metabolic pathways (TCA cycle, HMP pathway) and specific enzymes (NADH oxidase, rhodanese, thiosulfate oxidase).

Main Results:

• The new isolate, Thiobacillus acidophilus, has a G+C content of 62.9-63.2%.
• Optimal growth occurs at 25-30°C and pH 3.0, with growth possible between pH 1.5 and 6.0.
• It is a facultative autotroph, utilizing elemental sulfur and various organic compounds (e.g., glucose, citrate, amino acids) for energy.
• Key enzymes of the tricarboxylic acid (TCA) cycle and hexose monophosphate pathway were detected.
• Enzymes like NADH oxidase, rhodanese, and thiosulfate oxidase were identified.

Conclusions:

• Thiobacillus acidophilus represents a novel species with versatile metabolic capabilities.
• Its ability to utilize diverse organic compounds alongside sulfur makes it ecologically significant.
• The presence of specific enzymes suggests its role in sulfur metabolism and energy generation.