D-Allulose 3-epimerase of Bacillus sp. origin manifests profuse heat-stability and noteworthy potential of D-fructose epimerization

• Published in: Microbial cell factories 2021-03, Vol.20 (1), p.60-60, Article 60
• Main Authors: Patel, Satya Narayan, Kaushal, Girija, Singh, Sudhir P
• Format: Article
• Language: English
• Subjects: Amino acids; Bacillus; Bacillus (Bacteria); Bacillus - enzymology; Bacillus - genetics; Bacillus sp; Biocatalysis; Bioconversion; Biosynthesis; Carbohydrate Epimerases - chemistry; Carbohydrate Epimerases - genetics; Carbohydrate Epimerases - isolation & purification; Carbohydrate Epimerases - metabolism; Chemical properties; d-Allulose; d-Allulose 3-epimerase; Diabetes mellitus; Enzyme Stability; Enzymes; Epimerase; Ethanol; Ethanol - metabolism; Fermentation; Food products; Fructose; Fructose - biosynthesis; Gene expression; Heat; Hot Temperature; Hydrogen bonds; Hydrogen-Ion Concentration; Isomerases; Kinetics; Low calorie; Microbial enzymes; Microbiological research; Microbiological synthesis; Models, Molecular; Phylogeny; Physiological aspects; Probiotics; Production processes; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins; Saccharomyces cerevisiae - metabolism; Stability; Stereochemistry; Substrate Specificity; Thermal properties; Thermostability; Turnover number; Yeasts
• ISSN: 1475-2859; 1475-2859
• DOI: 10.1186/s12934-021-01550-1

D-Allulose is an ultra-low calorie sugar of multifarious health benefits, including anti-diabetic and anti-obesity potential. D-Allulose 3-epimerase family enzymes catalyze biosynthesis of D-allulose via epimerization of D-fructose. A novel D-allulose 3-epimerase (DaeB) was cloned from a plant probiotic strain, Bacillus sp. KCTC 13219, and expressed in Bacillus subtilis cells. The purified protein exhibited substantial epimerization activity in a broad pH spectrum, 6.0-11.0. DaeB was able to catalyze D-fructose to D-allulose bioconversion at the temperature range of 35 °C to 70 °C, exhibiting at least 50 % activity. It displaced excessive heat stability, with the half-life of 25 days at 50 °C, and high turnover number (k 367 s ). The coupling of DaeB treatment and yeast fermentation of 700 g L D-fructose solution yielded approximately 200 g L D-allulose, and 214 g L ethanol. The novel D-allulose 3-epimerase of Bacillus sp. origin discerned a high magnitude of heat stability along with exorbitant epimerization ability. This biocatalyst has enormous potential for the large-scale production of D-allulose.