Abstract

CONTINUOUS PRODUCTION OF GLUCONIC ACID AND FRUCTOSE USING MEMBRANE BIOREACTOR

*Luiz Carlos Martins Das Neves and Michele Vitolo

ABSTRACT

This study deals with the conversion of sucrose to fructose and gluconic acid by using the enzymes invertase (E.C. 3.2.1.26), glucose oxidase (E.C. 1.1.3.4), and catalase (E.C. 1.11.1.6) in a bioreactor coupled to a 100 kDa-ultrafiltration membrane. The parameters changed were dilution rate (D) (1.0 to 6.0 h-1) and concentration of sucrose (5-100 mM), glucose (5-1000 mM), invertase (3.0-24 UI/mL), glucose oxidase (10-40 UGO/mL), and catalase (0-800 UCAT/mL). A [sucrose/(fructose + gluconic acid)] conversion yield of about 90% was achieved through a two-step process. Hydrolysis consisted of treating a 20 mM sucrose solution with invertase (24 UI/mL) at D = 3.0 h-1, 35OC, pH 5.5, and agitation of 100 rpm. Then, the invert sugar solution obtained was treated with glucose oxidase (10 UGO/mL) and catalase (400 UCAT/mL) at the same conditions, except for temperature (30 OC).

Keywords: Membrane bioreactor, sucrose, gluconic acid, invertase, catalase, glucose oxidase.