ABSTRACT
Herein, a novel multifunctional enzyme ß-glucosidase/xylanase/feruloyl esterase (GXF) was constructed by fusion of ß-glucosidase and bifunctional xylanase/feruloyl esterase. The activities of ß-glucosidase, xylanase, feruloyl esterase and acetyl xylan esterase displayed by GXF were 67.18 %, 49.54 %, 38.92 % and 23.54 %, respectively, higher than that of the corresponding single functional enzymes. Moreover, the GXF performed better in enhancing aroma and quality of Longjing tea than the single functional enzymes and their mixtures. After treatment with GXF, the grassy and floral odors of tea infusion were significantly improved. Moreover, GXF treatment could improve concentrations of flavonoid aglycones of myricetin, kaempferol and quercetin by 68.1-, 81.42- and 77.39-fold, respectively. In addition, GXF could accelerate the release of reducing sugars, ferulic acid and xylo-oligosaccharides by 9.48-, 8.25- and 4.11-fold, respectively. This multifunctional enzyme may have potential applications in other fields such as food production and biomass degradation.
Subject(s)
Camellia sinensis , Carboxylic Ester Hydrolases , Tea , beta-Glucosidase , Carboxylic Ester Hydrolases/chemistry , Carboxylic Ester Hydrolases/metabolism , beta-Glucosidase/chemistry , beta-Glucosidase/metabolism , Camellia sinensis/chemistry , Camellia sinensis/enzymology , Tea/chemistry , Endo-1,4-beta Xylanases/chemistry , Endo-1,4-beta Xylanases/metabolism , Odorants/analysisABSTRACT
A rapid and convenient method for extracting DNA from soil is presented. Soil DNA is extracted by direct cell lysis in the presence of EDTA, SDS, phenol, chloroform and isoamyl alcohol (3-methyl-1-butanol) followed by precipitation with 2-propanol. The extracted DNA is purified by modified DNA purification kit and DNA gel extraction kit. With this method, DNA extracted from humus-rich dark brown forest soil was free from humic substances and, therefore, could be used for efficient PCR amplification and restriction digestion. In contrast, DNA sample extracted with the traditional CTAB-based method had lower yield and purity, and no DNA could be extracted from the same soil sample with a commonly-used commercial soil DNA isolation kit. In addition, this method is time-saving and convenient, providing an efficient choice especially for DNA extraction from humus-rich soils.
