Fed-batch production of tetanus toxin by Clostridium tetani.

This study deals with the effects of the initial nitrogen source (NZ Case TT) level and the protocol of glucose addition during the fed-batch production of tetanus toxin by Clostridium tetani. An increase in the initial concentration of NZ Case TT (NZ(0)) accelerated cell growth, increased the consumption of the nitrogen source as well as the final yield of tetanus toxin, which achieved the highest values (50-60 L(f)/mL) for NZ(0) > or = 50 g/L. The addition of glucose at fixed times (16, 56, and 88 h) ensured a toxin yield ( approximately 60 L(f)/mL) about 33% higher than those of fed-batch runs with addition at fixed concentration ( approximately 45 L(f)/mL) and about 300% higher than those obtained in reference batch runs nowadays used at industrial scale. The results of this work promise to substantially improve the present production of tetanus toxin and may be adopted for human vaccine production after detoxification and purification.

Isolation of bacteriophage-like particles from uninduced Clostridium tetani cultures.

The isolation of hexagonal-headed, tailless, bacteriophage-like particles from uninduced cultures of Clostridium tetani is described. Clear, round, 1--3 mm diameter plaques were noted on Clostrisel agar plates, which were overlaid with soft agar inoculated with 7--14 day broth cultures. Particles were detected by transmission electron microscopy from broth cultures seeded with scrapings from the plaques. Both electron dense and electron lucent heads were noted. An electron dense head was observed attached to the surface of a dividing bacterium.