Characterisation of a cold-active and salt-tolerant esterase from Lactobacillus plantarum with potential application during cheese ripening

During cheese ripening, the metabolic activity of microorganisms influences cheese flavour. Lactobacillus plantarum is a non-starter lactic acid bacterium that can be found during cheese ripening. An esterase-encoding gene from L. plantarum, lp_3505, was cloned and expressed in Escherichia coli BL21 (DE3). The biotechnologically produced Lp_3505 protein was purified as an active soluble form using His-tag affinity chromatography. The enzyme has an optimal pH and temperature of 6 and 5 °C, respectively. The enzyme showed remarkable stability at 20 °C, retaining more than 60% of its maximal activity after 20 h incubation at this temperature. In addition, NaCl concentrations lower than 20% increased esterase activity. The cold-activity and salt-tolerance exhibited by Lp_3505 indicated that this esterase could be a useful exogenous enzyme to be added for cheese ripening.