Requires light and a special medium, growing atypically on nutrient agar. Spirillum serpens Of morphological interest. May grow on nutrient agar but requires very frequent subculturing to maintain viability. Grows on nutrient agar. Nutrient agar with added glucose can be used but grows better on special medium, as for Lactobacillus .
Streptomyces griseus Responsible for the earthy odour of soil.
Grows to form a fungus-like, branching mycelium with aerial hyphae bearing conidia. Produces the antibiotic streptomycin, although a suitable strain is required to demonstrate this convincingly. Grows on nutrient or glucose nutrient agar but better on special medium which enhances formation of conidia. Thiobacillus ferrooxidans Involved in the bacterial leaching of sulphur-containing coal. Demonstrates bacterial leaching of coal samples containing pyritic sulphur.