The Genus Clostridium

Anaerobic Spore-forming Bacteria

By Harold Eddleman, Ph. D.

Growth and study of Clostridium species from soil, manure, and plant materials is easy for the beginning student using only foods found in any kitchen. The various Clostridium species have many differing traits and you could have a lot of fun studying a large number of Clostridium strains which you isolated all by yourself. Since Clostridium species do not use oxygen, they do not oxidize their food to water and carbon dioxide. Instead the end produces of Clostridium metabolism are fatty acids and other organic compounds many of which are volatile and have strong odors. Therefore, most growing cultures of Clostridium species have a strong odor. Some of the odor of mud, and decaying plant materials, or decaying proteins is due to substances produced by Clostridium species.

It is easy to pasteurize a sample and grow Clostridium species in mixed culture. However, growing them on a streaked plate requires the absence of oxygen and this is somewhat difficult without Bray dishes and other special items. However, it is simple to grow most species of Clostridium in test tubes of suitable medium. Some species of Clostridium grow best on carbohydrates but not as well on protein. Some other species of Clostridium grow best on protein media. A few species of Clostridium grow very well on on either of these media.

This is the Index Page. The other pages in this series are listed below

CL00 - Interesting reasons to start a Clostridim project. Start with a pan of boiling water and soil.
BA01 - The Bacillaceae family consists to 50+ species of Bacillus and 60+ species of Clostridium species and less than a dozen miscellaneous sporeformers.
BA02 - The Genus Bacillus
CL02 - The Genus Clostridium

Bacillus is a large genus of bacteria which are able to form spores in the presence of oxygen. Bacillus and Clostridum are common in soil, manure, and plant material. Bacillus species are easy to isolate from pasteurized soil because the spores can withstand boiling water which can then be plated on sterile agar, gelatin, or potato slices in the presence of air (oxygen present). Most of the colonies which grow will be Bacillus.

Clostrium species also form spores which survive boiling water, but the Closterium species can not form spores in the presence of oxygen. Most clostridia are aerotolerant (they survive exposure to air), but most species of Clostridium do not resume growth if oxygen is present. Clostridium species will be covered in pages to be started in early February.

To be continued in a few days.

Revision #1 1998 January 27


Written by Harold Eddleman, Ph. D., President, Indiana Biolab, 14045 Huff St., Palmyra IN 47164
Please help write this page by sending me an e-message containing your questions. indbio@disknet.com