High alkalinity inhibited sugar utilization by the alkalosensitive fungus (P. albicans) and increased the polysaccharide content in its fungal mats. The total amino-N content decreased in the culture of P. albicans, whereas its quantity increased in the biomass with progressive alkalinity. Alkalinity inhibited nitrogen uptake and protein synthesis leading to a corresponding decline in growth, and hence apparent alkalosensitivity. High alkalinity, caused enhancement of sugar uptake by the facultative alkolophile V. lateritium associated with higher reducing sugar contents and decreased polysaccharide accumulation in mycelial mats. The amino-N content increased in the culture medium of V. lateritium and decreased in the biomass with pH elevation. The utilization of soluble nitrogen increased, accompanied by increased protein synthesis, leading to maximum growth at higher pHs, and hence apparent alkalophilicity. The sodium ion content in the medium of the alkalosensitive fungus decreased at high pHs associated with respective increase in the biomasses. Oppositely, in the alkalophilic fungus, the sodium ion content increased in culture and decreased in biomasses with increased alkalinity, indicating an important role played by this ion. No clear relation could be obtained between phosphorus content in cultures or biomasses of the two tested fungi and alkalophilicity.