The process described in the present work uses air supplementation in a fluidized bed reactor containing Bacillus firmus strain 37 immobilized on active bovine bone charcoal, to produce by batch fermentation the enzym...The process described in the present work uses air supplementation in a fluidized bed reactor containing Bacillus firmus strain 37 immobilized on active bovine bone charcoal, to produce by batch fermentation the enzyme CGTase (cyclomaltodextrin-glucanotransferase). Three different aeration rates were evaluated. The maximum CGTase activity was achieved after 120 hours of fermentation with aeration rate of 2 vvm and was equal to 2.48 U/mL. When 0.5 and 1 vvm were used the enzymatic activities achieved 1.1 and 0.57 U/mL, respectively. Bovine bone charcoal was characterized in terms of surface area, pore size and volume. To the best of our knowledge, the immobilization of microorganism cells in bovine bone charcoal for CGTase production has not been reported in the literature. Our results showed that fluidized bed reactor allows retaining high concentration of biomass, improving biomass-substrate contact and operation at low residence times, which resulted in improved enzyme production. Therefore, the process as proposed has great potential for industrial development.展开更多
C-Oligosaccharides are rare in nature and possess diverse bioactivities.However,their chemical synthesis faces many challenges.In this work,enzymatic introduction of C-linked sugar chains to target aglycones was succe...C-Oligosaccharides are rare in nature and possess diverse bioactivities.However,their chemical synthesis faces many challenges.In this work,enzymatic introduction of C-linked sugar chains to target aglycones was successfully achieved by multi-enzymatic cascade reactions.A C-glycosyltransferase from Aloe barbadensis was employed to introduce the first C-linked glucose and then a cyclomaltodextrin glucanotransferase from Bacillus licheniformis was used to extend the sugar chain.A total of twenty C-oligosaccharides with 2-6 sugars were synthesized from scale-up reactions and exhibited good water solubility and sodium-dependent glucose transporter 2(SGLT2)inhibitory activity.Furthermore,a glucoamylase was used to control the length of the sugar chain and the C-maltosides were efficiently synthesized.These findings not only expanded the structural diversity of C-oligosaccharides,but also provided a strategy for the modification of C-glycoside drugs to improve the druggability.展开更多
文摘The process described in the present work uses air supplementation in a fluidized bed reactor containing Bacillus firmus strain 37 immobilized on active bovine bone charcoal, to produce by batch fermentation the enzyme CGTase (cyclomaltodextrin-glucanotransferase). Three different aeration rates were evaluated. The maximum CGTase activity was achieved after 120 hours of fermentation with aeration rate of 2 vvm and was equal to 2.48 U/mL. When 0.5 and 1 vvm were used the enzymatic activities achieved 1.1 and 0.57 U/mL, respectively. Bovine bone charcoal was characterized in terms of surface area, pore size and volume. To the best of our knowledge, the immobilization of microorganism cells in bovine bone charcoal for CGTase production has not been reported in the literature. Our results showed that fluidized bed reactor allows retaining high concentration of biomass, improving biomass-substrate contact and operation at low residence times, which resulted in improved enzyme production. Therefore, the process as proposed has great potential for industrial development.
基金financially supported by the National Key Research and Development Program of China(No.2020YFA0908000)CAMS Innovation fund for Medical Sciences(No.2021-I2M-1–029)。
文摘C-Oligosaccharides are rare in nature and possess diverse bioactivities.However,their chemical synthesis faces many challenges.In this work,enzymatic introduction of C-linked sugar chains to target aglycones was successfully achieved by multi-enzymatic cascade reactions.A C-glycosyltransferase from Aloe barbadensis was employed to introduce the first C-linked glucose and then a cyclomaltodextrin glucanotransferase from Bacillus licheniformis was used to extend the sugar chain.A total of twenty C-oligosaccharides with 2-6 sugars were synthesized from scale-up reactions and exhibited good water solubility and sodium-dependent glucose transporter 2(SGLT2)inhibitory activity.Furthermore,a glucoamylase was used to control the length of the sugar chain and the C-maltosides were efficiently synthesized.These findings not only expanded the structural diversity of C-oligosaccharides,but also provided a strategy for the modification of C-glycoside drugs to improve the druggability.
