Optimization of phenyllactic acid production by Pediococcus acidilactici CRL 1753. Application of the formulated bio-preserver culture in bread

Abstract Phenyl lactic acid (PLA) is an antimicrobial agent with a broad antimicrobial spectrum produced mainly by lactic acid bacteria. This study focused in the optimization of a low-cost medium to obtain biomass and PLA production by Pediococcus (Ped.) acidilactici CRL 1753 strain and propose its use as a liquid bio-preserver in bread making to increase the shelf life of wheat bread. First, the activity of CRL 1753 strain against filamentous fungi and yeasts was study and a wide antifungal inhibitory spectrum was observed. Using a factorial design 2 9-5 an optimized and low-cost medium (10 g/L meat peptone, 5 g/L yeast extract, 10 g/L glucose, 0.0038 g/L MnSO 4 , 6 g/L K 2 HPO 4 and initial pH = 7.0) that could replace MRS was obtained. A significant increase in shelf life was observed when calcium propionate (CP) and CRL 1753 strain were combined into the bread formulation. In fact, at 18 days of storage none moulds were observed when the liquid bio-preserver was added while 70% of breads were spoilage with CP alone. In this work we report for the first time the obtaining of an optimized low-cost culture medium for biomass and PLA production by Ped. acidilactici strain. The results obtained could be very useful as a basis to design new strategies that allow improve the PLA production at a low cost.