Properties of Cholesterol Dissimilation by Rhodococcus equi

Area of Science:

• Microbiology
• Biochemistry
• Food Science

Background:

• Serum cholesterol is a known risk factor for coronary heart disease.
• Reducing dietary cholesterol intake is a public health objective.
• Developing methods for cholesterol removal from food is a research challenge.

Purpose of the Study:

• To investigate the potential of Rhodococcus equi extracts for cholesterol degradation.
• To quantify cholesterol reduction in egg yolk and cream using bacterial extracts.
• To determine optimal conditions for cholesterol degradation by Rhodococcus equi.

Main Methods:

• Treatment of egg yolk and cream with sonicated extracts of Rhodococcus equi.
• Measurement of cholesterol reduction rates over time.
• Analysis of degradation products using thin-layer chromatography.
• Determination of optimal temperature, pH, and enzyme stability.

Main Results:

• Rhodococcus equi extracts removed up to 40% of cholesterol from egg yolk preparations.
• Specific strains (R. equi 21107 and 33706) showed high degradation rates.
• Cholesterol degradation in cream was less pronounced (2.4% reduction).
• Optimal conditions for degradation were 40°C and pH 8.0; enzyme activity decreased at 60°C.
• Degradation products included 4-cholesten-3-one and 1,4-cholestadiene-3-one.

Conclusions:

• Sonicated extracts of Rhodococcus equi effectively degrade cholesterol in food matrices like egg yolk.
• This microbial approach presents a viable strategy for reducing dietary cholesterol.
• Further research into optimizing conditions and understanding the degradation pathway is warranted.