Bioproduction of D -psicose using permeabilized cells of newly isolated Rhodobacter sphaeroides SK011

Abstract

D-psicose exits in an extremely small amount in nature and is difficult to be chemically synthesized. Only three bacteria have been used in the biotransformation of D-psicose from D-fructose. In this paper, another bacterium which could convert D-fructose to D-psicose was isolated and identified as Rhodobacter sphaeroides. The process parameters of D-psicose production using permeabilized cells of Rhodobacter sphaeroides SK011 were optimized, including the permeabilization procedure: 0.1% (w/v) CTAB, 10min, and reaction conditions: cell concentration, 30g dry cell wt/L; concentration of substrate, 50g/L; 40°C, pH 9.0; reaction time, 8 h. Under the optimized conditions, the permeabilized cells produced approximately 6.5g/L D-psicose with a D-psicose productivity of 0.82g·L^−1·h^−1. This is the first report of bioproduction of D-psicose using permeabilized cells of Rhodobacter sphaeroides.