Enthalpy changes associated with the lactic fermentation of glucose

Area of Science:

• Microbiology
• Biochemistry
• Thermodynamics

Background:

• Lactic fermentation is a key metabolic process.
• Understanding the energetics of microbial metabolism is crucial.

Purpose of the Study:

• To quantify the enthalpy changes during glucose fermentation by Streptococcus faecalis.
• To measure heat production using direct calorimetry.

Main Methods:

• Direct calorimetry was employed to measure heat production.
• Growing cultures and washed cells of Streptococcus faecalis were used.
• Fermentation of glucose was monitored at 37°C.

Main Results:

• Heat production correlated with growth rate and extent.
• The measured enthalpy change for glucose fermentation to lactic acid was -29.1 cal/mmole.
• This value aligns with theoretical calculations for the product mixture.

Conclusions:

• The study provides precise thermodynamic data for lactic fermentation.
• Direct calorimetry is a valid method for assessing microbial growth and metabolism.
• The findings support the understanding of energy transformations in microbial systems.