Growth inhibitory properties of lactose fatty acid esters

Abstract EN

Sugar esters are biodegradable, nonionic surfactants which have microbial inhibitory properties.

The influence of the fatty acid chain length on the microbial inhibitory properties of lactose esters was investigated in this study.

Specifically, lactose monooctanoate (LMO), lactose monodecanoate (LMD), lactose monolaurate (LML) and lactose monomyristate (LMM) were synthesized and dissolved in both dimethyl sulfoxide (DMSO) and ethanol.

Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined in growth media.LMLwas the most effective ester, exhibitingMICvalues of <0.05 to<5 mg/ml for each Gram-positive bacteria tested (Bacillus cereus, Mycobacterium KMS, Streptococcus suis, Listeria monocytogenes, Enterococcus faecalis, and Streptococcus mutans) and MBC values of <3 to <5 mg/ml for B.

cereus, M.

KMS, S.

suis, and L.

monocytogenes.LMDshowed MIC andMBCvalues of <1to <5 mg/ml for B.

cereus, M.KMS, S.

suis, L.

monocytogenes, and E.

faecalis, with greater inhibition when dissolved in ethanol.

LMM showed MIC and MBC values of <1 to <5 mg/ml for B.

cereus, M.

KMS, and S.

suis.

LMO was the least effective showing aMBCvalue of<5 mg/ml for only B.

cereus, thoughMICvalues for S.

suis and L.

monocytogenes were observed when dissolved inDMSO.

B.

cereus and S.

suis were the most susceptible to the lactose esters tested, while S.

mutans and E.

faecalis were the most resilient and no esters were effective on Escherichia coli O157:H7.

This research showed that lactose esters esterified with decanoic and lauric acids exhibited greater microbial inhibitory properties than lactose esters of octanoate and myristate against Gram-positive bacteria.