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

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]

Efficacy of chemical and microbiological treatment in improving the nutritional value of some plant residues, as feed for ruminants

The results of this study revealed the fact that the in vitro digestibility, biomass yield or mycelium yield efficiency ratio [MER] of the experimental fungi markedly differed with various plant residues, type and concentration of chemicals as well as the subsequential process [washing or neutralization]. Increased the alkali concentration favored the mycelial yield; a phenomenon that was furthered with washing the residual alkali and extended to the MER particularly with H. fuscoatra strain two grew on Ca[OH]2-rice straw and maize stalks. However, neutralization caused an increase in the in vitro digestibility more pronounced with rice straw, maize stalks or Kochia pretreated with conc. NaOH. The results of fermentation studies indicated that both strains achieved the best fungal felts and MER when grown on 20 g L-1 in plant residue for four-day residence time. On the basis of mycelial yield and substrated digestibility, fungi varied, among strains, in their effectiveness where H. fuscoatra strain two proved to be superior to strain 1. Despite the fact that alkali-pretreatment highly abated the protein content of all plant residues especially with conc. NaOH followed by washing, yet the combination of chemical and fermentation treatments drastically improved the nutritive value of plant residues as judged by their content of crude protein; more prominently with rice straw. Therefore, the combined treatment of such materials might be a logical alternative which exhibits a much greater improvement. Fortunately, the best treatment process for Atriplex, on the basis of protein content, was its fermentation with H. fuscoatra strain two

Some environmental and nutritional factors affecting the growth of two strains of humicola fuscoatra

The effects of different pH values, yeast extract concentrations, nitrogenous sources or concentrations of NH4Cl and Ca[NO3]2 on the growth criteria of two strains H. fuscoatra were investigated. The results clarified that the linear growth of both fungi increased with progress of age, reaching maximum mostly during the fourth day of fungal growth. Both strains were more tolerant to acidic medium than to basic culture with an optimum lies around pH 6.4. This coincided with acceleration of the daily growth rate in response to the latter pH value. Yeast extract exhibited a significant stimulatory effect of the linear growth in consistency with the application rate; more prominently with strain one. However, 0.6-1.2 g yeast extract L-1 induced higher gain in the radial growth and the daily growth rate of strain one compared with the respective controls, with minor, if at all differences in response to dose, a phenomenon that was also noticed with strain two, but at lower concentrations. NH4Cl and Ca[NO3]2 proved to be the best in supporting the linear growth, the daily growth rate and the mycelial biomass of the tested fungi, whereas urea being the least. Although strains one and two produced good biomass yield with 1.2 g NL-1 of Ca[NO3]2, yet the highest yield was achieved by such fungi with 0.6 and 2.4 g NL-1 of NH4Cl, respectively, indicating a higher secretion of soluble nitrogen metabolites by strain two in response to NH4Cl and to a lesser degree with Ca[NO3]2 than that of strain one

Antifungal potentiality of the insecticide nuvacron

Fungal strains were isolated from Zagazig soil, Aniger, PNotatum and Acandidus were the most dominant as well as FSporotrichiodes and AHumicola were also isolated from seedlings of cotton suffering from damping off diseaseThese fungi survived 3600, 1400, 1200, 1200 and 1000 ppm nuvacron in solid media respectivelyA lag phase of 24 and 48 hr was recorded when Ahumicola and FSporotrichiodes were grown at 800 ppm concentration, while it extended to 96 and 48 hr when high doses [1000 ppm] were appliedThis was the case with saprophytic fungi but at higher dosesReduction of the mean mycelial growth was correlated with application rates of the insecticideA reduction of 50% [from control] in colony diameter was affected by 100-200, 300-400, 500, 600-800 and 800 ppm nuvacron for AHumicola, Pnotatum, Fsporotrichiodes, Acandidus and Aniger respectivelyThe development of conidia was inhibited when nuvacron was incorporated with the solid mediumIncrease doses consistently increased the inhibitory effect on asexual spore-bearing organs, more prominently on phytopathogenic fungiTherefore, it is recommended to apply nuvacron not only for insect control, but also for achieving economic levels of fungal disease