RESUMO
Talaromyces thermophilus galactolipase (TTL) was found to produce alcohol sugar fatty acid diesters. The modulation of the solvent composition was used for the esterification reaction screening of diesters from xylitol and various fatty acids using the immobilized Talaromyces thermophilus galactolipase. The reactions were assessed by LC-MS analysis. The antimicrobial activity assay showed that both xylitol dicaprylate and xylitol dilaurate esters had more ability to inhibit the growth of several bacteria involved in surface contamination in the food industry. The xylitol dilaurate ester has the highest activity against Gram-positive strains with the lowest MIC values of 0.0016 and 0.005 mg mL-1 against Bacillus licheniformis and Staphylococcus aureus, respectively. Xylitol dicaprylate ester is more active against Gram-negative ones with significantly low MIC values of 0.25 and 0.4 mg mL-1 against Escherichia coli and Pseudomonas aeruginosa, respectively. The highest antifungal activity of the xylitol dicaprylate ester has been also proven, with a MIC value of 0.02 mg mL-1 against Penicillium occitanis and Fusarium solani. A better reduction in critical micelle concentrations and air-water surface tension were observed with these diesters compared to their corresponding monoesters in addition to their efficient emulsifying properties. The stability of these diesters in a liquid detergent formula after one year of storage was tested by a positive oil spreading assay and a retained antimicrobial activity. They exhibit a typical surfactant behavior with a two-in-one effect that can act as a detergent and a disinfectant with potential use in different cleaning processes.