Bioconversion of Egg Cholesterol to Pro-vitamin D Sterols with Tetrahymena Thermophila

G. VALCARCE; A. NUSBLAT; J. FLORIN-CHRISTENSEN; B.C. NUDEL

JOURNAL OF FOOD SCIENCE

Blackwell Publishing, Inc

Lugar: Estados Unidos; Año: 2002 vol. 67 p. 2405 - 2409

0022-1147

ABSTRACT: The potential use of the non-pathogenic ciliate Tetrahymena thermophila for converting cholesterol into pro-vitamin D sterols in egg suspensions was investigated. Conditions screened for efficient conversion included inoculum size and age, egg and egg yolk dilution, initial pH, and aeration. By optimizing these parameters, 55% ± 6 cholesterol reduction was obtained in 24 hours incubation. Tetrahymena converted cholesterol into three unsaturated sterols, D7,22 bis-dehydrocholesterol, an ergosterol analog (27%), D7-dehydrocholesterol, also known as pro-vitamin D3 (4%), and Ä22- dehydrocholesterol (8%). Despite significant proteolysis, culturing with Tetrahymena did not result in net consumption of total amino acids content, which was in fact increased by 16% ± 2. These findings emphasize the potential use of Tetrahymena in the food industry.