The production of L-tryptophan through che- mical synthesis, direct fermentation, bioconversion and enzymatic conversion has been reported. However, the role of the transport system for the aromatic amino acids in L- ...The production of L-tryptophan through che- mical synthesis, direct fermentation, bioconversion and enzymatic conversion has been reported. However, the role of the transport system for the aromatic amino acids in L- tryptophan producing strains has not been fully explored. In this study, the atop gene of the L-tryptophan producing Escherichia coli TRTH strain was disrupted using Red recombination technology and an atoP mutant E. coli TRTH AaroP was constructed. Fed-batch fermentation of E. coli TRTH △aroP was carried out in 30-L fermentor to investigate the L-tryptophan production. Compared with E. coli TRTH, the atoP mutant was able to maintain a higher growth rate during the exponential phase of the fermentation and the L-tryptophan production increased by 13.3%.展开更多
Ring-opening polymerization(ROP)represents a powerful tool for synthesizing functional polymers,distinguished by its exceptional control over polymerization processes and the facile incorporation of diverse backbone f...Ring-opening polymerization(ROP)represents a powerful tool for synthesizing functional polymers,distinguished by its exceptional control over polymerization processes and the facile incorporation of diverse backbone functionalities.However,ROP of strainlessmonomers remains challenging due to their unfavorable thermodynamics.To address this limitation,irreversible ROP that substantially shifts the equilibrium towards polymerization by introducing additional thermodynamically favorable processes has emerged as a versatile and innovative approach.This minireview highlights representative examples of irreversible ROP from three strategies:(1)ROP driven by functional group transformation/isomerization;(2)ROP driven by gas molecule liberation;(3)alternating ROP(AROP),with an emphasis on the design principle and reaction mechanism.It is anticipated that these discussions will provide valuable insights into irreversible ROP.展开更多
文摘The production of L-tryptophan through che- mical synthesis, direct fermentation, bioconversion and enzymatic conversion has been reported. However, the role of the transport system for the aromatic amino acids in L- tryptophan producing strains has not been fully explored. In this study, the atop gene of the L-tryptophan producing Escherichia coli TRTH strain was disrupted using Red recombination technology and an atoP mutant E. coli TRTH AaroP was constructed. Fed-batch fermentation of E. coli TRTH △aroP was carried out in 30-L fermentor to investigate the L-tryptophan production. Compared with E. coli TRTH, the atoP mutant was able to maintain a higher growth rate during the exponential phase of the fermentation and the L-tryptophan production increased by 13.3%.
基金supported by start-up funds generously provided by Jilin University.
文摘Ring-opening polymerization(ROP)represents a powerful tool for synthesizing functional polymers,distinguished by its exceptional control over polymerization processes and the facile incorporation of diverse backbone functionalities.However,ROP of strainlessmonomers remains challenging due to their unfavorable thermodynamics.To address this limitation,irreversible ROP that substantially shifts the equilibrium towards polymerization by introducing additional thermodynamically favorable processes has emerged as a versatile and innovative approach.This minireview highlights representative examples of irreversible ROP from three strategies:(1)ROP driven by functional group transformation/isomerization;(2)ROP driven by gas molecule liberation;(3)alternating ROP(AROP),with an emphasis on the design principle and reaction mechanism.It is anticipated that these discussions will provide valuable insights into irreversible ROP.
