Trehalose production via merged secretion, purification, and immobilization of trehalose synthase in Bacillus subtilis

Here, we established a one-step reaction method using trehalose synthase to produce trehalose from maltose. Bacillus subtilis was used as an expression host, and the various B. subtilis signal peptides and chitin-binding domains (ChBD) from Bacillus circulans WL-12 chitinase A1 were fused with the N- and C-termini, respectively, of trehalose synthase from the Picrophilus torridus DSM 9790 (PTTS) gene. Results showed that trehalose synthase was secreted by the YwbN signal peptide of B. subtilis and bound specifically to the chitin beads. The conversion yield of the immobilized enzyme was up to 69.07%, which was higher than that of the free enzyme (65.40%). Furthermore, the immobilized enzyme also retained 50% of its residual activity after the 21st repeated use. The chitin beads maintained 55% adsorption capacity after being reused 53 times. The results indicate the potential usefulness of the developed approach for trehalose production. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.