Growth and hydrocarbon degradation by three desert fungi under conditions of simultaneous temperature and salt stress

High temperature and salinity are stress conditions that prevail in the Kuwaiti desert, so that extensive crude oil pollution of the environment following hostile action necessitates investigation of petroleum hydrocarbon bioremediation under such conditions. Of three microfungi isolated from a salt marsh in the Kuwaiti desert, two (Fusarium lateritium and Drechslera sp.) grew in the presence of 10% NaCl, and the third (Papulaspora sp.) in 5% NaCl, at 35 °C, above which temperature growth was greatly reduced. Comparison of growth and crude oil degradation in the absence of stress (0% NaCl and 25 °C) and under stress (10% NaCl and 35 °C) showed that crude oil degradation was not markedly affected in F. lateritium and Drechslera by stress, but was dependent on the nutritional status of the growth medium. The effect of NaCl concentration on biomass development, which was lower in minimal medium than in the rich medium (PDB), appeared to be the principal factor determining hydrocarbon degradation by the microfungi under simultaneous temperature and halo-stress.