Hydroxylation of Fatty Acids by Lactic Acid Bacteria

Hydroxy fatty acids (HFAs) are fatty acids with hydroxyl functional groups attached to the main chain. HFAs are used in widely diverse industrial applications, healthy functional foods, artificial food flavorings, and alcoholic beverages. A lactic acid bacterium (LAB), Lactobacillus sakei, hydroxylates oleic acid. Furthermore, the hydroxyl fatty acid was identified by GC-MS as 10-hydroxystearic acid. The Lactobacillus sakei hydroxylated more than 90% of the oleic acid in the medium at 15 °C after 30-48 h. The hydroxyl enzyme needs a coenzyme for an electron donor as NADPH. The enzyme is useful for assay with monitoring NADPH concentration used an A340 device. The hydroxylate fatty acids are converted by LAB lactonize aroma lactone from commercial yeast strains, which can be detected directly by scent. Commercial beer brewing yeast T-58 produced the highest concentration of aroma lactone from hydroxyl fatty acids. Furthermore, the aroma lactone is identified by GC-MS as gamma-dodecalactone. The ratio of conversion is 87%. These results suggest that the lactonization conversion system is useful to hydroxylate fatty acids for alcoholic beverages.