Characterization of a halotolerant lipase from the lactic acid bacteria Lactobacillus plantarum useful in food fermentations

- Lipases are widely used in the food industry.
- Lactobacillus plantarum posses an halotolerant lipase stable under 25% NaCl.
- L. plantarum halotolerant lipase showed activity on food fermentation conditions.

Lactobacillus plantarum is a lactic acid bacteria found in fermented foods on which high salt concentrations are present. So far, no salt-tolerant lipase has been described from lactic acid bacteria. In the present study, the gene lp_3562 encoding a putative esterase/lipase was cloned and expressed in Escherichia coli BL21 (DE3) and the overproduced Lp_3562 protein has been biochemically characterized. Lp_3562 is a lipase active on tributyrin and also on other long chain substrates. Although the highest activity was observed at pH 7, the enzyme showed activity at pH 5.0-8.0. Lp_3562 exhibited optimal lipase activity at 40 °C and, showing more than 40% of maximal activity at refrigeration temperature (5 °C). Conversely, Lp_3562 presented good thermostability exhibiting more than 80% of its maximal activity after 20 h incubation at 45 °C. More interestingly, Lp_3562 was active under NaCl concentrations higher than 20%. The biochemical properties exhibited by Lp_3562 make this halotolerant lipase attractive for its use in food fermentations.