Autodisplay of an endo-1,4-β-xylanase from Clostridium cellulovorans in Escherichia coli for xylans degradation.
The goal of this work was the autodisplay of the endo β-1,4-xylanase (XynA) from Clostridium cellulovorans in Escherichia coli using the AIDA system to carry out whole-cell biocatalysis and hydrolysate xylans. For this, pAIDA-xynA vector containing a synthetic xynA gene was fused to the signal peptide of the toxin subunit B Vibro cholere (ctxB) and the auto-transporter of the synthetic aida gene, which encodes for the connector peptide and β-barrel of the auto-transporter (AT-AIDA). E. coli TOP10 cells were transformed and the biocatalyst was characterized using beechwood xylans as substrate. Optimal operational conditions were temperature of 55 °C and pH 6.5, and the Michaelis-Menten catalytic constants Vmax and Km were 149 U/gDCW and 6.01 mg/mL, respectively. Xylanase activity was inhibited by Cu2+, Zn2+ and Hg2+ as well as EDTA, detergents, and organic acids, and improved by Ca2+, Co2+ and Mn2+ ions. Ca2+ ion strongly enhanced the xylanolytic activity up to 2.4-fold when 5 mM CaCl2 were added. Also, Ca2+ improved enzyme stability at 60 and 70 °C. Results suggest that pAIDA-xynA vector has the ability to express functional xylanase to perform whole-cell biocatalysis in order to hydrolysate xylans from hemicellulose feedstock.
['Balderas Hernández|Victor E|VE|', 'Salas-Montantes|Carlos J|CJ|', 'Barba-De la Rosa|Ana P|AP|', 'De Leon-Rodriguez|Antonio|A|']
D046974:Clostridium cellulovorans D043364:Endo-1,4-beta Xylanases D004795:Enzyme Stability D004926:Escherichia coli D006863:Hydrogen-Ion Concentration D013696:Temperature D014990:Xylans
Autodisplay AIDA Xylanase Hemicellulose Whole cell biocatalysts