Toshinari Maeda, Takayuki Yoshimura, Rodolfo García-Contreras, Hiroaki I Ogawa
Department of Biological Functions and Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu 808-0196, Japan. toshi.maeda@life.kyutech.ac.jp
Bioresource technology 2011 NovA novel protease secreted by Brevibacillus sp. KH3 isolated from excess sludge at 50 °C and used as a sludge-lysing strain was investigated in this study. Sludge reduction was minimized by protease inhibitors and a 40-kDa protease, which significantly contributed to this sludge-reducing activity, was purified as the target protein. The final purified protease demonstrated 92-fold higher specific activity than the initial crude extracts. The sludge-reducing efficiency deteriorated relative to decreased protease activity triggered by EDTA; thus, the purified protease was a causative agent in reducing excess sludge. The 40-kDa protease was a serine metalloprotease and showed the highest activity at 50 °C and pH 8.0, and the activity was enhanced in the presence of calcium ions, indicating that the purified protease contained calcium ion. Furthermore, this 40-kDa protease inhibited biofilm formation in excess sludge. These results imply that sludge reduction is because of reduction of biofilm formation in excess sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.
Toshinari Maeda, Takayuki Yoshimura, Rodolfo García-Contreras, Hiroaki I Ogawa. Purification and characterization of a serine protease secreted by Brevibacillus sp. KH3 for reducing waste activated sludge and biofilm formation. Bioresource technology. 2011 Nov;102(22):10650-6
PMID: 21925876
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