ABSTRACTAccumulation of biogenic amines (BAs) in cheese and other foods is a matter of public health concern. The aim of this study was to identify the enzyme activities responsible for BA degradation in lactic acid bacteria which were previously isolated from traditional Sicilian and Apulian cheeses. The selected strains would control the concentration of BAs during cheese manufacture. First, 431 isolates not showing genes encoding the decarboxylases responsible for BA formation were selected using PCR-based methods. Ninety-four out of the 431 isolates degraded BAs (2-phenylethylamine, cadaverine, histamine, putrescine, spermine, spermidine, tyramine, or tryptamine) during cultivation on chemically defined medium. As shown by random amplification of polymorphic DNA-PCR and partial sequencing of the 16S rRNA gene, 78 of the 94 strains wereLactobacillusspecies (Lactobacillus casei,Lb. fermentum,Lb. parabuchneri,Lb. paracasei,Lb. paraplantarum, andLb. rhamnosus),Leuconostocspecies (Leuconostoc lactisandLn. mesenteroides),Pediococcus pentosaceus,Lactococcus lactis,Streptococcusspecies (StreptococcusgallolyticusandS. thermophilus),Enterococcus lactis, andWeissella paramesenteroides. A multicopper oxidase-hydrolyzing BA was purified from the most active strain,Lb. paracaseisubsp.paracaseiCB9CT. The gene encoding the multicopper oxidase was sequenced and was also detected in other amine-degrading strains ofLb. fermentum,Lb. paraplantarum, andP. pentosaceus.Lb. paracaseisubsp.paracaseiCB9CT and another strain (CACIO6CT) of the same species that was able to degrade all the BAs were singly used as adjunct starters for decreasing the concentration of histamine and tyramine in industrial Caciocavallo cheese. The results of this study disclose a feasible strategy for increasing the safety of traditional cheeses while maintaining their typical sensorial traits.IMPORTANCEBecause high concentrations of the potentially toxic biogenic amines may be found in traditional/typical cheeses, the safety of these food items should be improved. Lactic acid bacteria selected for the ability to degrade biogenic amines may be used during cheese making to control the concentrations of biogenic amines.
Food-grade expression of multicopper oxidase with improved capability in degrading biogenic amines
