Biosynthesis of ascorbyl benzoate in organic solvents and study of its antioxygenic and antimicrobial properties

Ascorbyl benzoate was synthesized through lipase-catalyzed esterification in organic media, and its properties studied. A series of organic solvents with a log P from −1.30 to 2.50 were investigated, in which cylcohexanone (log P = 0.96) was found to be the most suitable. The optimum reaction conditions in cylcohexanone were pH 6.0, aw 0.33, a substrate concentration form 0.06 M to 0.1 M, 65 °C, and above 150 rpm speeds of shaking. Experimental results also demonstrated that benzoic acid was not an ideal substrate of lipase, which led to low conversion rates, but its limitation could be overcome by excess l-ascorbic acid. Schaal oven test illustrated that the antioxidant activity of ascorbyl benzoate was comparable to that of ascorbyl palmitate, and minimal inhibitory concentration (MIC) data showed that its antimicrobial activity was weaker than that of benzoic acid.