Production and Characterization of a Recombinant Cold-Active Acetyl Xylan Esterase from Psychrophilic Paenibacillus sp. R4 Strain

Abstract

Acetyl xylan esterases (AXEs) hydrolyze the specific ester linkages between acetic acid and xylose units, leading to the deacetylation and depolymerization of xylan. PbAcE, the AXE from the soil-psychrophilic Paenibacillus sp. R4 strain, was produced in recombinant E. coli with 1 mM isopropyl β-d-1-thiogalactopyranoside (IPTG). The final dry cell weight and purified PbAcE were 17 g/L and 657 mg/L using a 7-L bioreactor and, 6 g/L and 500 mg/L using a 30-L fermenter, respectively. The hydrolysis activity of PbAcE was approximately 27 U/mg when p-nitrophenyl was used as the substrate. PbAcE was most active at pH 8.0 and it maintained more than 80% activity from pH 4.0 to pH 11.0 compared to the maximum value under the given conditions. Furthermore, PbAcE deacetylated cephalothin and chromomycin A3 antibiotics. The current study demonstrates that the production of PbAcE was successful, and the results may encourage further application studies.