Separation of 5-aminovalerate from its bioconversion liquid by macroporous adsorption resin: mechanism and dynamic separation

BACKGROUND: 5-aminovalerate (5-AVA) is the precursor of valerolactam, a potential building block for producing nylon 5, and also regarded as a potential C5 chemical platform. Although 5-AVA bioproduction has been developed, few studies have emphasized the separation of 5-AVA from the bioconversion liquid. RESULTS: An effective and benign method for separation of 5-AVA from its bioconversion liquid was proposed based on chromatography technology using macroporous adsorption resin AK-1. This work focuses on explosion of the adsorption mechanism and optimization of the operating conditions. Freundlich model and thermodynamics results showed that the adsorption affinity of 5-AVA to the AK-1 resin was weaker than that of l-lysine. Combination of the characterization results of AK-1 resin with the physicochemical properties of 5-AVA and l-lysine, the adsorption mechanism was proposed as meso-micropore diffusion, and hydrogen bonding and hydrophobic effects. In dynamic studies, a 5-AVA purity of 99.3% and yield of 92% was obtained at an operating temperature of 353.15 K on a 40:1 chromatographic column eluted by deionized water. The residual 5-AVA and l-lysine were recovered by 1 mol L^–1 HCl, which can be used as a feed material in the 5-AVA conversion process repeatedly. CONCLUSION: An innovative benign efficient environmentally process for recovery of 5-AVA from the bioconversion liquid was developed based on a macroporous resin AK-1. Compared with ion exchange resins, macroporous resins can efficiently adsorb 5-AVA, whereas salt ions cannot be retained. This clean and efficient method provides a promising strategy for separating similar biochemical products.