Proteolytic activity of beef luncheon fungi as affected by incorporation of some food preservatives.

Screening of thirty-one fungal isolates (representing 16 genera, 28 species and 3 varieties) collected from beef luncheon meat for their abilities to produce protease enzyme revealed that eleven isolates (35.48%) exhibited high protease production. However, fifteen isolates (48.39%) had moderate ability and 5 isolates (16.13%) were low producers. Aspergillus flavus, Gibberella fujikuroi and Penicillium chrysogenum were the most active producers of protease. The incorporation of five chemical substances used as food preservatives (disodium phosphate, sodium benzoate, citric acid, potassium sorbate and sodium citrate) individually in the culture medium for protease production exhibited depressive effect on protease production as well as on mycelial growth of Aspergillus flavus, Gibberella fujikuroi and Penicillium chrysogenum , except in few cases the mycelial growth of A. flavus and G. fujikuroi was increased by the lowest concentration (100 ppm) of sodium benzoate, citric acid and disodium phosphate.

Fungi associated with the hairs of goat and sheep in libya.

The mycoflora on the hair in 25 samples of each of goats and sheep collected from Libya was analyzed using two isolation methods at 25℃. Seventy species and 3 varieties belonging to 31 genera were collected from the two substrates. The hairs of sheep were polluted with fungi than goat, contained high total counts and number of genera and species. Two species of true dermatophytes were isolated namely Trichophyton rubrum and T. terrestre. Several keratiophilic species were isolated of which Chrysosporium indicum, C. keratinophilum and C. tropicum were the most prevalent. The commonest saprophytes in order of frequency were members of the genera Aspergillus, Penicillium, Emericella, Alternaria and Cochliobolus.

Ecological and physiological studies on soil fungi at Western region, libya.

Sixty three species and 5 varieties belonging to 30 fungal genera were collected from 75 soil samples. Cultivated (29 genera and 58 species + 5 var.), desert (22 and 35 + 2 var.) and saline soil (21 and 41 + 1 var.) fungi were recovered on glucose-, cellulose- and 50% sucrose-Czapek's agar at 28℃. The most common genera were Alternaria, Aspergillus, Emericella, Fusarium, Mycosphaerella, Nectria and Penicillium. The most prevalent species from the three types of soils on the three types of media were Alternaria alternata, Aspergillus flavus, A. fumigatus, A. niger, A. terreus, Emericella nidulans, Fusarium oxysporum, Mycosphaerella tassiana, Nectria haematococca and Penicillium chrysogenum. Chaetomium globosum was in the top of fungi in producing endo-ß-1,4-glucanases among the 42 tested isolates obtained from soils on cellulose-Czapek's agar. Maximum production of this enzyme by C. globosum obtained after 6 days of incubation at 30℃ with culture medium containing maltose as a carbon source and ammonium nitrate as a nitrogen source and pH initially adjusted to 6.

Effect of herbizid and touchdown herbicides on soil fungi and on production of some extracellular enzymes.

Glucophilic and cellulose-decomposing fungi were significantly reduced in soil samples treated with 0.019-0.152 mg a.i./kg soil of the herbicides Herbizid and Touchdown. The decrease was regularly correlated with the doses of the two herbicides and persisted till the end of the experiment (12 weeks). The isolated fungi were found to be able to produce hydrolytic extracellular enzymes in solid media but with variable capabilities. The ability to produce enzymes was adversily affected by the incorporation of herbicides in culture media. Lower doses of herbicides were occasionally promotive to enzyme production and mycelial growth of some fungi. Incorporation of 50 ppm of Herbizid and Touchdown significantly activated amylase production and mycelial dry weight in cultures of Fusarium oxysporum, Mucor hiemalis and Penicillium chrysogenum. There was a significant increase in C1-cellulase produced by F. oxysporum and P. aurantiogriseum when cultures were treated with 50, 100 and 200 ppm of Herbizid which induced also more Cx-cellulase production by P. chrysogenum. Lipase and protease production was always lower in treated than in control fungal cultures.

Effect of two systemic fungicides on cellulose decomposing fungi of tomato plants and on some enzymatic activities.

Kocide 101 (77% cupric hydroxide) and Ridomil plus (15% metalaxyl and 35% copper oxychloride) were used in the treatment of tomato plants. The two fungicides exerted a depressive effect on the total counts and on the individual cellulose decomposing fungal species associated with the roots and shoots of tomato. When these fungicides were incorporated in the liquid culture medium specified for growth and extracellular enzyme production by some selected fungal species, there was a significant reduction in mycelial growth as well as in amylase, cellulase, lipase and protease production by the fungi tested, particularly at the higher doses (200-400 ppm). Exceptions were observed with lower doses (50 and 100 ppm) especially in case of Aspergillus flavus, Cunninghamella echinulata, Penicillium chrysogenum and Fusarium oxysporum grown for amylase or cellulase production.