Characterisation of an Oleuropein Degrading Strain of Lactobacillus plantarum. Combined Eþects of Compounds Present in Olive Fermenting Brines (Phenols, Glucose and NaCl) on Bacterial Activity

Characterisation of an Oleuropein Degrading Strain of Lactobacillus plantarum. Combined Eþects of Compounds Present in Olive Fermenting Brines (Phenols, Glucose and NaCl) on Bacterial Activity

Characterisation of an Oleuropein Degrading Strain of Lactobacillus plantarum. Combined Eþects of Compounds Present in Olive Fermenting Brines (Phenols, Glucose and NaCl) on Bacterial Activity

Abstract

This study aims to examine the e†ects of glucose and NaCl on the
ability of an oleuropein degrading strain of L actobacillus plantarum, strain B21,
to grow in the presence of oleuropein, its degradation product, hydroxytyrosol,
and p-coumaric acid. Oleuropein (10 g litre~1) and 2 g litre~1 hydroxytyrosol
combined with NaCl did not inhibit bacterial growth, whereas 1 g litre~1 pcoumaric acid showed low inhibitory activity. This study also presents that bacterial b-glucosidase and esterase are involved in the breakdown of oleuropein.
Oleuropein (10 g litre~1) incorporated in the cultivation medium without glucose
was completely degraded to derivative products within 20 days, whereas in the
presence of glucose, at concentrations up to 50 g litre~1 b-glucosidase activity
was partially inhibited, and 30È70% of oleuropein residual content remained in
the cultivation medium. Esterase activity involved in the second step of biodegradation process, was not inÑuenced by glucose. Incorporation of glucose in the
growth medium adversely a†ected the ability of L plantarum to break-down oleuropein. The Ðndings of this study are signiÐcants since it could lead to the development of a new biotechnology for removing the bitter principle, oleuropein,
from olives replacing the traditional alkali treatment used for debittering olives.

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