Chapter 12 - Degradation of phenolic compounds found in olive products by Lactobacillus plantarum strains

Abstract

Lactobacillus plantarum (currently Lactiplantibacillus plantarum) is the main bacterial species associated to olive processing. During the last years, numerous studies have been carried out on the metabolism of phenolics compounds by L. plantarum strains, due to the great importance of these compounds in the health beneficial properties of olive products. Among the olive phenolic acids studied, some hydroxycinnamic acids (caffeic, m-coumaric, o-coumaric, p-coumaric, ferulic, and sinapic acids) as well as some hydroxybenzoic acids (gallic and protocatechuic acids) were metabolized by L. plantarum. The decarboxylase and reductase enzymes responsible for these biochemical reactions have been identified, recombinantly produced, and biochemically characterized. Oleuropein, the main secoiridoid glucoside present in olives, is hydrolyzed by L. plantarum by the sequential action of unidentified enzymes, giving elenoic acid and hydroxytyrosol as end-products. It has been also studied the response of L. plantarum to some olive-related compounds (olive oil, p-coumaric acid, gallic acid, and oleuropein) by genome-scale transcriptomic signature and physiological analysis.