An automated quantitative assay for fungal growth inhibition

A simple technique which enables the monitoring of fungal growth with the aid of a microplate reader is described. In the absorbance range of 0 to 0.6 units, a straight-line relationship exists between absorbance at 595 nm and dry weight of microplate cultures, indicating that culture absorbance is an accurate indicator of fungal biomass. The relative standard deviation of the absorbance measurements was low (typically between 2 and 6%) when spores were used for inoculum. With inoculi consisting of mycelial fragments, slightly higher standard deviations (ca. 10%) were found. The microplate reader technique is particularly suited for determination of growth inhibition curves, since it is extremely fast, reliable, and requires as little as 75 μl of total culture volume.