Sulfur and the Toxicity of the Red Alga Ceramium Rubrum to Bacillus Subtilis1,2

SUMMARY Crystalline sulfur has been isolated from the red seaweed Ceramium rubrum and shown to be responsible for the toxicity of this alga to the growth of Bacillus subtilis. This alga was unusual in that it contained a much higher free sulfur content than other red and brown algae tested.