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| Cordeiro,Carlos Alberto Martins; Martins,Meire Lelis Leal; Luciano,Angélica Bárbara; Silva,Roberta Freitas da. |
| An aerobic, thermophilic, xylanolytic bacterium was isolated from local soil. The results of 16S rRNA sequence comparisons indicated that the isolate was closely related to Bacillus caldoxylolyticus and Bacillus sp strain AK1. These organisms exhibited 94% levels of ribossomal DNA sequence homology. Studies on the xylanase characterisation from liquid cultures grown on beechwood xylan revealed that the enzyme retained 100% of activity for 2 hours at temperatures ranging from 30 to 50º C, while at 60, 70 and 100º C, 10%, 11% and 29% of the original activities were lost, respectively. The optimum pH of the enzyme was found to be between 6.5 and 7.0. After incubation of crude enzyme solution for 24 hours at 25º C and at pH 5.5 to 8.0, a decrease of about 12%... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Xylanase; Thermophilic bacterium; Bacillus sp. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000600002 |
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| Cordeiro,Carlos Alberto Martins; Martins,Meire Lelis Leal; Luciano,Angélica Bárbara. |
| alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) production by thermophilic Bacillus sp strain SMIA-2 cultivated in liquid media containing soluble starch reached a maximum at 48h, with levels of 57U/mL. Studies on the a-amylase characterization revealed that the optimum temperature for activity was 70ºC. The enzyme was stable for 2h at 50ºC, while at 60ºC, 70ºC and 90ºC, 4%, 13% and 38% of the original activities were lost, respectively. The optimum pH of the enzyme was 7.5. After incubation of crude enzyme solution for 24h at pH 7.5, a decrease of about 5% of its original activity was observed. The enzyme was strongly inhibited by Co2+, Cu2+ and Ba2+, but less affected by Ca2+, Mg2+, Ni2+, Sr2+ and Mn2+. The enzyme in 1M and 5M NaCl... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Alpha-amylase; Thermophilic bacterium; Bacillus sp.. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000100012 |
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