Hydrolysis of esters by staphylococci

Area of Science:

• Food Microbiology
• Enzymology
• Biochemistry

Background:

• Staphylococci are common bacteria in food production.
• Understanding their enzymatic activity is crucial for food quality and safety.
• Ester hydrolysis by bacteria can impact flavor profiles through free fatty acid release.

Purpose of the Study:

• To characterize ester hydrolysis by staphylococci.
• To determine if staphylococci contribute to free fatty acid release in sausages.
• To investigate the esterase and lipase activities of various staphylococcal species.

Main Methods:

• Assessed cell-free extracts and extracellular concentrates of staphylococci.
• Tested esterase activity using p-nitrophenyl esters.
• Evaluated lipolytic activity against triolein.
• Analyzed enzyme activity under varying temperature, pH, and water activity conditions.

Main Results:

• Staphylococci exhibited both intracellular and extracellular esterase activities with distinct electrophoretic patterns.
• Specific species like S. xylosus, S. warneri, and S. saprophyticus showed preferential hydrolysis of certain p-nitrophenyl esters.
• Extracellular concentrates of some staphylococci hydrolyzed triolein, indicating lipase activity.
• Optimal hydrolysis occurred between 15-25°C; acidic conditions and reduced water activity inhibited activity.

Conclusions:

• Staphylococci possess diverse esterase and lipase activities.
• These enzymatic activities suggest a role in free fatty acid generation in food products like sausages.
• Environmental factors such as temperature, pH, and water activity significantly influence staphylococcal ester hydrolysis.