This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Miyamoto, T.
Right arrow Articles by Kasai, N.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Miyamoto, T.
Right arrow Articles by Kasai, N.
Agricola
Right arrow Articles by Miyamoto, T.
Right arrow Articles by Kasai, N.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2009, p. 5058-5063, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00122-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Inactivation of Escherichia coli Endotoxin by Soft Hydrothermal Processing{triangledown}

Toru Miyamoto,* Shinya Okano, and Noriyuki Kasai

Institute for Animal Experimentation, Graduate School of Medicine, Tohoku University, Sendai, Japan

Received 19 January 2009/ Accepted 1 June 2009

Bacterial endotoxins, also known as lipopolysaccharides, are a fever-producing by-product of gram-negative bacteria commonly known as pyrogens. It is essential to remove endotoxins from parenteral preparations since they have multiple injurious biological activities. Because of their strong heat resistance (e.g., requiring dry-heat sterilization at 250°C for 30 min) and the formation of various supramolecular aggregates, depyrogenation is more difficult than sterilization. We report here that soft hydrothermal processing, which has many advantages in safety and cost efficiency, is sufficient to assure complete depyrogenation by the inactivation of endotoxins. The endotoxin concentration in a sample was measured by using a chromogenic limulus method with an endotoxin-specific limulus reagent. The endotoxin concentration was calculated from a standard curve obtained using a serial dilution of a standard solution. We show that endotoxins were completely inactivated by soft hydrothermal processing at 130°C for 60 min or at 140°C for 30 min in the presence of a high steam saturation ratio or with a flow system. Moreover, it is easy to remove endotoxins from water by soft hydrothermal processing similarly at 130°C for 60 min or at 140°C for 30 min, without any requirement for ultrafiltration, nonselective adsorption with a hydrophobic adsorbent, or an anion exchanger. These findings indicate that soft hydrothermal processing, applied in the presence of a high steam saturation ratio or with a flow system, can inactivate endotoxins and may be useful for the depyrogenation of parenterals, including end products and medical devices that cannot be exposed to the high temperatures of dry heat treatments.

* Corresponding author. Mailing address: Graduate School of Medicine, Tohoku University, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan. Phone: 81-22-717-8175. Fax: 81-22-717-8180. E-mail: miyamoto{at}mail.tains.tohoku.ac.jp

{triangledown} Published ahead of print on 5 June 2009.

Applied and Environmental Microbiology, August 2009, p. 5058-5063, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00122-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»