Production and biochemical characterization of a high maltotetraose (G4) producing amylase from Pseudomonas stutzeri AS22.

Amylase production and biochemical characterization of the crude enzyme preparation from Pseudomonas stutzeri AS22 were evaluated. The highest α-amylase production was achieved after 24 hours of incubation in a culture medium containing 10 g/L potato starch and 5 g/L yeast extract, with initial pH 8.0 at 30°C under continuous agitation at 200 rpm. The optimum temperature and pH for the crude α -amylase activity were 60°C and 8.0, respectively. The effect of different salts was evaluated and it was found that both α -amylase production and activity were Ca(2+)-dependent. The amylolytic preparation was found to catalyze exceptionally the formation of very high levels of maltotetraose from starch (98%, w/w) in the complete absence of glucose since the initial stages of starch hydrolysis (15 min) and hence would have a potential application in the manufacturing of maltotetraose syrups.