H₂ Consumption by Various Acetogenic Bacteria Follows First-Order Kinetics up to H₂ Saturation.

Area of Science:

• Microbiology
• Biotechnology
• Biochemistry

Background:

• Acetogenic bacteria are crucial in biotechnology, converting CO2 and H2 into acetate.
• Hydrogen (H2) availability often limits acetogenesis, necessitating kinetic studies.
• Understanding H2 consumption kinetics is vital for optimizing biotechnological applications.

Purpose of the Study:

• To investigate the H2 consumption kinetics of acetogenic bacteria.
• To determine if acetogenesis follows first-order or Monod kinetics.
• To quantify H2 consumption rates and identify factors influencing them.

Main Methods:

• Measuring initial H2 consumption rates across varying H2 concentrations for three acetogen strains.
• Applying first-order kinetics and Monod kinetics models for analysis.
• Validating rate coefficients using prior time-course experimental data.

Main Results:

• H2 consumption in acetogens followed first-order kinetics, not Monod kinetics as previously assumed.
• H2 consumption rates increased linearly with dissolved H2 concentration up to saturation.
• Biomass-specific first-order rate coefficients (k1X) varied significantly among strains, with Acetobacterium wieringae showing the highest and Sporomusa sphaeroides the lowest.

Conclusions:

• Dissolved H2 concentration is a critical factor governing acetogenesis rates in biotechnological systems.
• First-order kinetics accurately describes H2 consumption by acetogens under tested conditions.
• Kinetic data provides valuable insights for enhancing acetogenesis efficiency in industrial applications.