Protease and esterase activity of staphylococci

Area of Science:

• Food Microbiology
• Enzymology
• Bacteriology

Background:

• Staphylococci are key in fermented sausage ripening.
• Protease and esterase activities influence flavor and texture.
• Understanding these enzymes aids starter culture development.

Purpose of the Study:

• Characterize protease and esterase activities in Staphylococcus species.
• Determine their role in amino acid and short-chain fatty acid release.
• Evaluate potential for starter culture selection.

Main Methods:

• Screened 18 Staphylococcus strains (S. xylosus, S. saprophyticus, S. equorum, S. carnosus, S. simulans) for enzymatic activity.
• Assayed proteinase, aminopeptidase, and esterase activities using specific substrates.
• Quantified enzyme activity in whole cells, cell-free extracts, and extracellular medium.

Main Results:

• Most strains showed low proteinase and aminopeptidase activity.
• All strains exhibited significant esterase activity, particularly against short-chain fatty acid esters (rho-NP butyrate and rho-NP caprylate).
• S. xylosus and S. equorum strains displayed the highest esterase activities.

Conclusions:

• Staphylococcal esterase activity is crucial for ripening processes in fermented sausages.
• Enzyme activity varies significantly between species and strains.
• In vitro characterization is vital for selecting effective starter cultures.