title: Enhanced biocatalytic production of L-cysteine by Pseudomonas sp. B-3 with in situ product removal using ion-exchange resin.
abstract: Bioconversion of DL-2-amino-Δ(2)-thiazoline-4-carboxylic acid (DL-ATC) catalyzed by whole cells of Pseudomonas sp. was successfully applied for the production of L-cysteine. It was found, however, like most whole-cell biocatalytic processes, the accumulated L-cysteine produced obvious inhibition to the activity of biocatalyst and reduced the yield. To improve L-cysteine productivity, an anion exchange-based in situ product removal (ISPR) approach was developed. Several anion-exchange resins were tested to select a suitable adsorbent used in the bioconversion of DL-ATC for the in situ removal of L-cysteine. The strong basic anion-exchange resin 201 × 7 exhibited the highest adsorption capacity for L-cysteine and low adsorption for DL-ATC, which is a favorable option. With in situ addition of 60 g L(-1) resin 201 × 7, the product inhibition can be reduced significantly and 200 mmol L(-1) of DL-ATC was converted to L-cysteine with 90.4 % of yield and 28.6 mmol L(-1 )h(-1) of volumetric productivity. Compared to the bioconversion without the addition of resin, the volumetric productivity of L-cysteine was improved by 2.27-fold using ISPR method.
authors.affiliation: College of Pharmaceutical Science, Zhejiang University of Technology, Chaowang Road 18, Hangzhou, 310032, People's Republic of China, wangpu@zjut.edu.cn.
authors.forename: Pu
authors.initials: P
authors.lastname: Wang
authors.forename: Jun-Yao
authors.initials: JY
authors.lastname: He
authors.forename: Jiang-Feng
authors.initials: JF
authors.lastname: Yin
mesh_terms: D003545:Cysteine / Q000096:biosynthesis* / Q000302:isolation & purification*; D007475:Ion Exchange Resins / Q000737:chemistry*; D011549:Pseudomonas / Q000254:growth & development*
chemical_list: D007475:Ion Exchange Resins; D003545:Cysteine