Effect of plant residue additions and temperature on growth criteria of thermophilous cellulolytic fungi from Egyptian soil

ABSTRACT

The results of this study indicated that incorporation of plant residues into the soil at 50 degrees increased the densities of thermophilic cellulolytic fungi; more prominently with rice or wheat straw. Moreover, irrespective of cellulosic supplements, wheat straw followed by cellulose powder, as a sole C-substrate in the medium, induced the highest counts, whereas alfalfa seemed the least in this regard. The preliminary investigation revealed that Humicola fuscoatra dominated the soil, though Thermomyces lanuginosus followed by Populospora thermophila were high during the middle part of incubation periods, whereas the least was Malbranchea sulfurea which was totally absent after 30 days incubation. The results further showed that the fastest growth rate for all fungi occurred at 50 degrees, however, P. thermophila failed to grow above 52 degrees, whereas the other fungi grew at 60 degrees. In response to 50 degrees, the daily growth rate and the relative growth rate [RGR] of both strains of H. Fuscoatra started by an appreciably high levels then decreased continuously with age whereas both criteria increased with time, reaching maximum during the middle part of the incubation period under the stress of temperature extremes [33, 58 and 60 degrees]