Physiological and enzymatic characterization of a novel pullulan-degrading thermophilicBacillusstrain 3183

✍ Scribed by Gwo-Jenn Shen; Kailash C. Srivastava; Badal C. Saha; J. Gregory Zeikus

• Book ID: 104650884
• Publisher: Springer
• Year: 1990
• Tongue: English
• Weight: 527 KB
• Volume: 33
• Category: Article
• ISSN: 1432-0614
• DOI: 10.1007/bf00164533

✦ Synopsis

A new thermophilic Bacillus strain 3183 (ATCC 49341) was isolated from hot-spring sediments. The organism grew on pullulan as a carbon source and showed optimum pH and temperature at pH 5.5 and 62 ° C, respectively, for growth. The strain reduced nitrate to nitrite both aerobically and anaerobically. It produced extracellular thermostable pullulanase and saccharidase activities which degraded pullulan and starch into maltotriose, maltose, and glucose. Medium growth conditions for pullulanase production were optimized. The optimum pH and temperature for pullulanase activity were at pH 6.0 and 75 ° C, respectively. The enzyme was stable at pH 5.5-7.0 and temperature up to 70 ° C in the absence of substrate. The K,, for pullulan at pH 6.0 and 75°C was 0.4 mg/ml. The pullulanase activity was stimulated and stabilized by Ca 2+. It was inhibited by ethylenediaminetetraacetate (EDTA), betaand gamma-cyclodextrins but not by alpha-cyclodextrin and reagents that inhibit essential enzyme SHgroups.