19481-10-8Relevant articles and documents
Multi-Enzymatic Cascade Reactions for the Synthesis of cis,cis-Muconic Acid
Di Nardo, Giovanna,Gazzola, Silvia,Gilardi, Gianfranco,Pollegioni, Loredano,Rosini, Elena,Valetti, Francesca,Vignali, Elisa
, p. 114 - 123 (2021/10/07)
Lignin valorization allows the generation of a number of value-added products such as cis,cis-muconic acid (ccMA), which is widely used for the synthesis of chemicals for the production of biodegradable plastic materials. In the present work, we reported the first multi-enzymatic, one-pot bioconversion process of vanillin into ccMA. In details, we used four sequential reactions catalyzed by xanthine oxidase, O-demethylase LigM (and the tetrahydrofolate-regeneration enzyme methyl transferase MetE), decarboxylase AroY (based on the use of E. coli transformed cells) and catechol 1,2-dioxygenase CatA. The optimized lab-scale procedure allowed to reach, for the first time, the conversion of 5 mM vanillin into ccMA in ～30 h with a 90% yield: this achievement represents an improvement in terms of yields and time when compared to the use of a whole-cell system. This multi-enzymatic system represents a sustainable alternative for the production of a high value added product from a renewable resource. (Figure presented.).
One-pot production of phenazine from lignin-derived catechol
He, Zhimin,Qi, Wei,Ren, Tianyu,Yan, Ning
supporting information, p. 1224 - 1230 (2022/02/17)
Upgrading lignin-derived monomeric products is crucial in bio-refineries to effectively utilize lignin. Herein, we report a simple strategy to convert catechol to phenazine, a useful N-heterocycle three-aromatic-ring compound, whose current synthetic procedure is complex via a petroleum-derived feedstock. The reaction uses catechol as the sole carbon source and aqueous ammonia as reaction media and a nitrogen source. Without additional solvents, phenazine was obtained in 67% yield in the form of high purity crystals (>97%) over a Pd/C catalyst after a one-pot-two-stage reaction. When cyclohexane was used as a co-solvent in the first step, a higher yield (81%) and purity (>99%) were achieved. Mechanistic investigations involving control experiments and an isotope labeling study reveal that hydrogenation, amination, coupling and dehydrogenation reactions are the key steps leading to phenazine formation. The conversion of other lignin-derived catechols highlights that the protocol is extendable to produce substituted phenazines.
High-throughput assay of tyrosine phenol-lyase activity using a cascade of enzymatic reactions
Hu, Wen-Ye,Tang, Xiao-Ling,Zheng, Ren-Chao,Zheng, Yu-Guo,Zhu, Hang-Qin
, (2022/01/19)
Tyrosine phenol-lyase (TPL) exhibits great potential in industrial biosynthesis of L-tyrosine and its derivates. To uncover and screen TPLs with excellent catalytic properties, there is unmet demand for development of facile and reliable screening system for TPL. Here we presented a novel assay format for the detection of TPL activity based on catechol 2,3-dioxygenase (C23O)-catalyzed reaction. Catechol released from TPL-catalyzed cleavage of 3,4-dihydroxy-L-phenylalanine (L-DOPA) was further oxidized by C23O to form 2-hydroxymuconate semialdehyde, which could be readily detected by spectrophotometric measurements at 375 nm. The assay achieved a unique balance between the ease of operation and superiority of analytical performances including linearity, sensitivity and accuracy. In addition, this assay enabled real-time monitoring of TPL activity with high efficiency and reliability. As C23O is highly specific towards catechol, a non-natural product of microorganism, the assay was therefore accessible to both crude cell extracts and the whole-cell system without elaborate purification steps of enzymes, which could greatly expedite discovery and engineering of TPLs. This study provided fundamental principle for high-throughput screening of other enzymes consuming or producing catechol derivatives.
