HPLC analysis of catalyzed products of starch and glucose by recombinant enzymes. (a) Hydrolysis products of starch catalyzed by purified RpGla; (b) Hydrolysis products of starch catalyzed by purified RpAmy; (c) Hydrolysis products of starch catalyzed by co-expressed enzyme preparation; (d) Blank control: soluble starch processed under the same procedure with deactivated enzyme preparation. The loading amount was all 10 μl. Substrate solution was prepared by mixing 1 g of soluble starch in 100 ml of citrate-sodium citrate buffer (50 mM, pH 5.0). 200 μl of appropriate diluted purified enzyme solution was added into 1 ml of substrate solution. After incubation at 50°C for 48 h, the mixture was boiled to stop the reaction and centrifuged. The retention time of glucose and maltose were about 5.0 min and 8.4 min respectively; (e) Reaction product of 40% glucose catalyzed by recombinant glucoamylase after 24 h of incubation at 50°C.