I want to test the growth rate of basidiomycetes on different carbon sources (fructose, maltose, glucose....). So far I tested an agar-media described in the paper "Carbon and Nitrogen Source Effects on Basidiomycetes Exopolysaccharide Production" (Elisashvilia et al. 2009). The media contains per liter:

carbon source: 20g

(NH4)2SO4 2g

KH2PO4 0.8g

Na2HPO4 0.4g

MgSO4 0.5g

yeast extract 3g

However, the basidiomycetes that I've tested also grew on my control-media which was without the 20g of carbon source. So I think the small amount of carbon in the yeast extract was enough for growth. So I need a media without an additional carbon source like yeast or malt.