Expression of heat-resistant β-glucosidase in Escherichia coli and its application in the production of gardenia blue

Abstract

Gardenia blue is a natural blue pigment that is environmentally friendly, non-toxic, and stable. The hydrolysis of geniposide, catalyzed by β-glucosidase, is a critical step in the production process of gardenia blue. However, β-glucosidase is not resistant to high temperatures, limiting the production of gardenia blue. In this study, we investigated the effectiveness of a heat-resistant glucosidase obtained from Thermotoga maritima in the production of gardenia blue. The enzyme exhibited a maximum activity of 10.60 U/mL at 90 °C. Single-factor and orthogonal analyses showed that exogenously expressed heat-resistant glucosidase reacted with 470.3 μg/mL geniposide and 13.5 μg/mL glycine at 94.2 °C, producing a maximum yield of 26.2857 μg/mL of gardenia blue after 156.6 min. When applied to the dyeing of denim, gardenia blue produced by this method yielded excellent results; the best color-fastness was achieved when an iron ion mordant was used. This study revealed the feasibility and application potential of microbial production of gardenia blue.

Isolation of the Thermostable β-Glucosidase-Secreting Strain Bacillus altitudinis JYY-02 and Its Application in the Production of Gardenia Blue

“…Recombinant β-glucosidase could be used for preparation of GB by catalyzing the hydrolysis of gardenia glycoside to produce genipin, followed by the reaction of genipin with amino acids, but the reaction efficiency was relatively low, with a reaction time of 8 h at 90°C. Li et al ( 11 ) expressed a heat-resistant β-glucosidase from Thermotoga maritima in E. coli and used it to produce GB. Single-factor and orthogonal analyses showed that exogenously expressed heat-resistant glucosidase reacted with geniposide and glycine at 94.2°C, producing a maximum yield of GB after 156.6 min.…”

“…S1 in the supplemental material). This method provides the GB with a higher level of purity but at a higher cost as well ( 11 ). Glycine, alanine, valine, leucine, and other amino acids can be used to prepare GB, and glycine is one of the most readily available amino acids in molecular laboratories ( 11 , 12 ).…”

“…This method shows the obvious advantages of high yields and a simple purification process. Currently, temperature is one of the major limitations on the production efficiency of GB ( 11 ). The reaction process of genipin with amino acids requires a high temperature, above 90°C; however, the lack of heat-resistant β-glucosidase limits the effective combination of two-step reactions ( 11 ).…”

“…Currently, temperature is one of the major limitations on the production efficiency of GB ( 11 ). The reaction process of genipin with amino acids requires a high temperature, above 90°C; however, the lack of heat-resistant β-glucosidase limits the effective combination of two-step reactions ( 11 ). β-Glucosidase with thermal stability is the key to solving this problem.…”

Sustainable fashion: eco-friendly dyeing of wool fiber with novel mixtures of biodegradable natural dyes

“…The GB and GY dyes were obtained from Wuhan Green Food Biological Engineering Co. Ltd. (China). The chemical structures of the main components of MR 34 , GB 35 , 36 , and GY 37 are shown in Fig. 1 .…”