Functionalized polyhydroxyalkanoate nano-beads as a stable biocatalyst for cost-effective production of the rare sugar d-allulose

Bioresour Technol. 2019 Oct:289:121673. doi: 10.1016/j.biortech.2019.121673. Epub 2019 Jun 19.

Abstract

d-Allulose is a promising low-calorie sweetener especially for diabetes and obesity patients. The functionalized polyhydroxyalkanoate (PHA) nano-beads decorated with d-tagatose 3-epimerase (DTE) was produced in recombinant endotoxin-free ClearColi, whereby the expression, purification, and immobilization of the active DTE were efficiently combined into one step. The immobilized DTE exhibited remarkable enzyme activity of 649.3 U/g beads and extremely high stability at a harsh working condition (pH 7.0-8.0, 65 °C). When DTE-PHA beads were subjected to enzymatic synthesis of d-allulose, a maximum conversion rate of 33% can be achieved at pH 7.0 and 65 °C for 3 h, and DTE-PHA beads retained about 80% of its initial activity after 8 continuous cycles. Moreover, the d-allulose/d-fructose binary mixture can be simply separated by a single cation exchange resin-equipped chromatography. Taken together, DTE-PHA beads are promising and robust nano-biocatalysts that will remarkably simplify the production procedures of d-allulose, contributing to its cost-effective production.

Keywords: Immobilization; Low-calorie sweetener; Polyhydroxyalkanoates; d-Allulose; d-Tagatose-3-epimerase.

MeSH terms

  • Biocatalysis
  • Cost-Benefit Analysis
  • Fructose / metabolism*
  • Hydrogen-Ion Concentration
  • Nanostructures
  • Polyhydroxyalkanoates / metabolism*
  • Racemases and Epimerases / metabolism

Substances

  • Polyhydroxyalkanoates
  • psicose
  • Fructose
  • Racemases and Epimerases