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Thermostable amylolytic enzymes from a new Clostridium isolate

Journal Article · · Appl. Environ. Microbiol.; (United States)
OSTI ID:5625620
A new Clostridium strain was isolated on starch at 60 degrees C. Starch, pullulan, maltotriose, and maltose induced the synthesis of alpha-amylase and pullulanase, while glucose, ribose, fructose, and lactose did not. The formation of the amylolytic enzymes was dependent on growth and occurred predominantly in the exponential phase. The enzymes were largely cell bound during growth of the organism with 0.5% starch, but an increase of the starch concentration in the growth medium was accompanied by the excretion of alpha-amylase and pullulanase into the culture broth; but also by a decrease of total activity. Alpha-amylase, pullulanase, and alpha-glucosidase were active in a broad temperature range (40 to 85 degrees C) and displayed temperature optima for activity at 60 to 70 degrees C. During incubation with starch under aerobic conditions at 75 degrees C for 2 hours, the activity of both enzymes decreased to only 90 or 80%. The apparent Km values of alpha-amylase, pullulanase, and alpha-glucosidase for their corresponding substrates, starch, pullulan, and maltose were 0.35 mg/ml, 0.63 mg/ml, and 25 mM, respectively. (Refs. 31).
Research Organization:
Institut fur Mikrobiologie der Georg-August Univ. Gottingen, 3400 Gottingen, Germany, F.R.; Nagoya Univ., Nagoya 464 Japan. Dept. Food Science and Technology, School of Agriculture
OSTI ID:
5625620
Journal Information:
Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 53:7; ISSN AEMID
Country of Publication:
United States
Language:
English