Production of β-Glucosidase via Fermentation of Aspergillus kawachii for the Sustainable Obtaining of the Blue Chromophore from Geniposide in a Simplified Process

Abstract

A. kawachii is of considerable importance in the food industry due to its enzyme production. The objective was to evaluate the feasibility of coupling β-glucosidase production by A. kawachii, to partially purify the enzymatic extract by gel filtration chromatography, and to preliminarily apply it to the bioconversion of geniposide into genipin to form a blue chromophore in a simplified process. β-glucosidase production was carried out via liquid fermentation in a glucose-tryptone medium over 54 h, and fermentation process parameters were monitored. Subsequently, the enzyme extract was fractionated by gel filtration chromatography (Hi-Trap G-25 column). The simplified process for the formation of the blue chromophore was carried out by mixing the fraction with β-glucosidase activity, geniposide (10 g/L), and glycine at different concentrations (1.0, 2.5, 5.0, 7.5, and 10.0 g/L), then incubating it at 40 °C for 48 h. The fermentation time for maximum β-glucosidase production (0.059 U/mL) was 48 h. Residual fermentation compounds were removed by chromatography, thereby partially purifying the enzyme (purification fold = 3.88) to prevent it from reacting with genipin. At 7.5 g/L glycine, a yield of 0.96 g/L of the blue chromophore was obtained. In conclusion, the use of enzymes enables a sustainable process for producing a blue chromophore. This chromophore can be considered a potential functional ingredient for the development of nutraceuticals and cosmeceuticals.