Ionozymes for Efficient Synthesis of Cadaverine: Offering a Sustainable Way for Bio-nylon 5X Production

Abstract

Bio-based cadaverine, a crucial monomer for the production of bio-nylon 5X, can be synthesized during the bioconversion of L-lysine HCl relying on lysine decarboxylases. The rationally designed lysine decarboxylase ΔLdcEt3 has exhibited outstanding alkaline stability in pH 8.0 (half-life: 362 h); however, its catalytic activity still needs to be improved to meet the requirements of industrial cadaverine production. A novel ionozyme strategy can create a preferable reaction microenvironment, affect the intermediate formation, and/or improve the enzymatic stability and activity. Therefore, ionozymes ΔLdcEt3-[Emim]Cl and ΔLdcEt3-[Ch][Ser] have been successfully developed for efficient cadaverine production in this study. The results showed that the catalytic activities of ΔLdcEt3-[Emim]Cl and ΔLdcEt3-[Ch][Ser] improved 124.2 and 116.2%, respectively. Meanwhile, the catalytic efficiencies (k cat /K m ) of ΔLdcEt3-[Emim]Cl and ΔLdcEt3-[Ch][Ser] were also increased by 1.5-and 1.2-fold, respectively. Particle size, circular dichroism, and Raman spectrum analyses showed that [Emim]Cl and [Ch][Ser] could affect short-range attractions related to the aggregation state and change the secondary structure. Protein surface analysis demonstrated that the addition of ionic liquids changed the hydrophobicity of ΔLdcEt3. In addition, isothermal titration calorimetry and molecular docking revealed that [Emim]Cl and [Ch][Ser] could promote the protein−ligand complexation during the enthalpy-driven L-lysine and ΔLdcEt3 binding process, which was confirmed by molecular dynamics. Therefore, ionozymes ΔLdcEt3-[Emim]Cl/[Ch][Ser] provide a novel possibility for high-level cadaverine production.

Long-Chain Bio-Based Nylon 514 Salt: Crystal Structure, Phase Transformation, and Polymerization

“…1,5-pentanediamine (PDA) is the main raw material for the production of series bio-nylon 5X, which opens up a new green production method due to its valuable industrial applications [ 18 , 19 , 20 ]. With the increasing maturity of biotechnology for preparing PDA from biomass resources such as corn straw [ 21 , 22 , 23 ], the synthetic routes and small-scale industrial application of series nylon 5X have been preliminarily established [ 24 ]. Nylon 514, which is polymerized by the crystalline salts of 1,5-pentanediamine-tetradecanedioate (abbreviated to as PDA-TDA; see Figure 1 , C 19 H 40 N 2 O 4 , M.W.…”

Hydrogen Bond Promoted Methoxycarbonylation of Pentanediamine to Biobased Dicarbamate by Accelerating Proton Transfer

“…This approach not only utilizes biomass-derived PDA, but also replaces nonrenewable feedstocks with greener alternatives, paving the way for the sustainable production of pentamethylene diisocyanate. 16,17 Traditional synthesis of carbamates involves the use of toxic phosgene and its derivatives, which are currently increasingly avoided because of environmental and safety concerns. A promising alternative to the phosgene-based synthesis is the direct carbonylation of amines with dimethyl carbonate (DMC), yielding N-substituted carbamates.…”

“…The substrate l -lysine has been successfully commercialized by extracting from biomass, making it an ideal raw material for producing PDA. This approach not only utilizes biomass-derived PDA, but also replaces nonrenewable feedstocks with greener alternatives, paving the way for the sustainable production of pentamethylene diisocyanate. , …”

Identification of coke species on Fe/USY catalysts used for recycling polyethylene into fuels

“…27 However, coking behaviors differ from that observed on pure zeolites due to Fe doping, which not only alters acidity and porosity but also facilitates H 2 production. 28 For example, adding Fe to a Ni–V/USY catalyst significantly reduces coke formation and increases the olefin-to-paraffin ratio during n -hexane cracking. 29 Clear identification of coke distribution and structure on Fe-based zeolites can guide the design of catalyst structures to resist coke deposition.…”