Unlocking the potential of Escherichia coli modified magnetic particles for chiral discrimination of racemic tryptophan

Enzymes possess a highly specific affinity toward their substrates. In this study, an enzyme-based biological method was established for chiral discrimination of D/L-tryptophan (Trp). The polydopamine modified magnetic particles (PDA@Fe3O4) were prepared for immobilization of the genetically engineered bacterium Escherichia coli (E. coli) DH5 alpha. The bacteria-magnetic particles conjugates (bacteria@PDA@Fe3O4) demonstrate excellent chiral discrimination performance toward D/L-Trp at pH 7.0 and 45 degrees C. The investigation for the principle exhibits that the immobilized E. coli DH5 alpha can produce tryptophanase, and the enzyme can selectively recognize and degrade L-Trp. The Michaelis constant of tryptophanase produced by bacteria@PDA@Fe3O4 was measured to be 25.7 mu g mL(-1). This method avoids the purification of tryptophanase and unlocks the potential of bacteria modified magnetic particles for chiral discrimination of racemic tryptophan. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Enzyme-based biological method using polydopamine modified magnetic particles for chiral discrimination of D/L-tryptophan demonstrated excellent performance, avoiding the purification of enzymes and unlocking the potential of bacteria modified magnetic particles in chiral discrimination.