New GH16 β-glucanase from Paenibacillus barcinonensis BP-23 releases a complex pattern of mixed-linkage oligomers from barley glucan

The gene coding for a lichenase from Paenibacillus barcinonensis BP-23, a powerful carbohydrate-degrading strain, was obtained using a genome walking strategy and expressed in Escherichia coli for further characterization. The amino acid sequence deduced from lic16A revealed that the lichenase is a single-domain enzyme belonging to the GH16 family. Purified recombinant Lic16A showed exclusive activity on -1,3-1,4-glucans, showing a K-m of 16.88 mg/mL and a V-max of 266.09 U/mg using lichenan as a substrate. Lic16A was stable at 55 degrees C for at least 3 H in moderate pH conditions. Thin-layer chromatography analysis showed that the enzyme released a complex mixture of hydrolysis products, which consisted of different length oligosaccharides of intermediate mobility among cellooligomers. The health benefits of -glucans's consumption and the increased interest for the use of their oligomers as prebiotics add interest to the study of Lic16A for the production of -glucan-derived oligosaccharides and the evaluation of their biotechnological potential. This is the first report on -1,3-1,4-glucanase produced by P. barcinonensis. (C) 2015 International Union of Biochemistry and Molecular Biology, Inc.