The abp gene in Geobacillus stearothermophilus T-6 encodes a GH27 β-l-arabinopyranosidase

► The abp gene from G. stearothermophilus encodes for a family 27 arabinopyranosidase. ► By using 13C NMR the removal of arabinopyranoside from galactan was demonstrated. ► A single residue, Ile 67 in Abp, appears to control substrate specificity.