Determination of Glucose

Samples were analyzed for glucose by high-performance liquid chro­matography using an Aminex HPX-87H column at 65°C. The mobile phase was 5 mM H2SO4 at a flow rate of 0.5 mL/min. In addition, glucose concen­trations in some samples were determined by an enzymatic glucose test (Boehringer Mannheim GmbH, Mannheim, Germany).

Enzyme Assay

Filter paper activity, which describes the overall cellulolytic activity of an enzyme preparation, was determined by the method of Mandels et al. (16). A 1 x 6 cm strip of Whatman no.1 filter paper (Hillsboro, OR), which equals 50 mg of cellulose, served as the substrate and was added to the sample solution containing 0.5 mL of appropriate diluted enzyme (super­natant of culture broth) and 1.0 mL of 0.05 M citrate buffer (pH 4.8). After 60 min of incubation at 50°C, the hydrolysis was terminated by the addition of 3 mL of DNS solution, and the mixture was further assayed for reducing sugar content by the DNS method. One international filter paper unit (FPU) was defined as the amount of enzyme that releases 1 gmol of glucose/min under the assay conditions. Activities were reported as FPU/milliliter.