Application of response surface methodology for optimizing arginine deiminase production medium for Enterococcus...

Area of Science:

• Microbiology
• Biotechnology

Background:

• Enterococcus faecium possesses an arginine deiminase pathway for arginine metabolism.
• Optimizing fermentation processes is crucial for enhancing microbial metabolic activity and product yield.

Purpose of the Study:

• To enhance arginine metabolism in Enterococcus faecium sp. GR7 via optimization of the arginine deiminase pathway.
• To determine optimal fermentation media and environmental conditions for increased arginine deiminase specific activity and biomass production.

Main Methods:

• Independent experiments were used to optimize fermentation media (EAPM).
• Response surface methodology with a five-level central composite design (CCD) was employed to study interactive effects of three process variables.
• Regression analysis and response surface plots were used to determine optimal media component concentrations and environmental conditions.

Main Results:

• Independent optimization of fermentation media resulted in a 4-fold increase in arginine deiminase specific activity.
• Response surface methodology achieved a 15-fold increase in arginine metabolism (arginine deiminase specific activity) over the basal medium.
• Optimal conditions yielded an arginine deiminase specific activity of 4.6 IU/mG and biomass production of 12.1 mg/L, with a model R-squared of 0.87-0.90.

Conclusions:

• Optimized fermentation parameters significantly enhance arginine metabolism and arginine deiminase activity in Enterococcus faecium sp. GR7.
• The optimized process provides a robust method for increasing yield of arginine deiminase from a GRAS strain.
• Enhanced arginine deiminase production supports further investigation into the in vitro therapeutic potential of E. faecium sp. GR7.