Physical and biochemical characterisation of bacteriocins produced by three Lactobacillus species
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Keywords

antimicrobial compound characterisation
bacteriocin activity
Lactic acid bacteria

Abstract

The bacteriocins produced by Lactic acid bacteria (LAB) species (L. plantarum L2, L. paraplantarum L5 and L. pentosus
L11) were characterized with respect to their sensitivity to heat, pH, cations, surfactants, inhibitors and papain. The
activity of bacteriocin produced by L. plantarum L2 and L. pentosus L11 was stable at 100?C for 20 minutes while 87.5%
of the activity of L. paraplantarum L5 bacteriocin was retained. The bacteriocin activity of L. pentosus L11 and
L. plantarum L2 was unaltered after 15 minutes autoclaving while there was a reduction in that of L. paraplantarum L5
(6.25%). The bacteriocin activity of the LAB strains at pH 3 to pH 5 was higher than the values of the control and pH 3
supported the highest activity in all the isolates. Tween 80 boosted all bacteriocin activity while 5 mM-10 mM of benzoic
acid augmented bacteriocin activity of L. plantarum L2. The activity of L. pentosus L11 bacteriocin was unaffected at all
concentrations of ammonium ion (NH4
+) used. At 5 mM concentrations of Ca2+, the activity of the three Lactobacillus
bacteriocins were slightly increased (10%). Crude papain and three fold aqueous dilutions of crude papain completely
inhibited bacteriocin activity. The properties exhibited by these bacteriocins are an indication that they and their producing
strains may find applications in industrial processes.

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