الفهرس 
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Abstract
The present study was investigated for lipid and biomass production using the isolated soil fungi. Thirteen fungal species were isolated and identified from soil collected from Tanta city, Gharbia Governorate, Egypt. The isolated fungal species belonging to four genera i.e. Aspergillus sp, Penicillium sp, Fusarium sp and Alernaria sp. Lipid content of the isolated fungi were evaluated in minimal medium after 7 days of incubation period on shaker incubator. The maximum lipid content were achieved with Aspergillus versicolor and Aspergillus niveus. The most promising lipid fungi which were identified previously by microscopic investigation as; A. versicolor and A. niveus were subjected, moreover, to molecular identification by 18S rRNA gene. The result of molecular identification of Aspergillus niveus indicated that the tested sequence had 99.14% similarity PCR sequence with their respective species, A. niveus, accession No: MH865243.1.The result of Aspergillus versicolor indicated that tested sequence had 98.91% similarity PCR sequence with their respective species, A. versicolor, accession No: JN689348.1. In studying the cultivation mode in A. niveus discovered that, shaking mode has a great effect on biomass production than static mode however in lipid production no marked difference was observed between the two modes. For A. versicolor shaking condition was preferred for both biomass and lipid production. Maximum lipid contents for A. niveus (23.38%) and A. versicolor (27.39%) were obtained after 11 and 5 days of incubation, respecively. By studying different initial pH values under shaking condition, it was found that pH 4 gave the highest lipid content of 30.74% of total dry weight for A. niveus and 30.21% in case of A. versicolor. Optimum temperature for maximum lipid production in A. niveus (33.93%) and A. versicolor (32.30%) is 32 oc. Glucose, Sucrose, maltose, dextrose and xylose as different carbon sources were tested for maximum lipid content, sucrose gave the highest lipid content of 35.74% in A. niveus and 33.14% in A. versicolor. Different sucrose concentrations were tested for maximum lipid contents, 20 g/Lin A. niveus and 40 g/Lin A. versicolor were the best for lipid production. Yeast extract, peptone, glycine, glutamic acid and sodium nitrate as different nitrogen sources were tested for maximum lipid content, sodium nitrate in A. niveus and glutamic acid in A. versicolor were the most suitable producing 41.37% and 40.89%, respectively. Different concentrations of sodium nitrate and glutamic acid were tested for maximum lipid content. In A. niveus, 1.0 g/L of sodium nitrate gave the maximum lipid content of 43.06% (g/g) and 0.5 g/L of glutamic acids in A. versicolor produced the highest level of lipid content of 40.99% (g/g). Three different types of agro-wastes (Solanum tubeorsum (Potato), Pisum sativum (Pea) and Eichhornia crassipes (Water hyacinth) were tested for lipid production, Water hyacinth in A. niveus and potato in A. versicolor gave the highest lipid content of 9.06% and 9.28%, respectively. Fresh household wastes medium supplemented by different concentration of sucrose for biomass and lipid production. In A. niveus the maximum biomass of 16.83 g/L was produced at concentration of 50 g/L of sucrose were tested however the maximum lipid content of 6.65 % was obtained at control medium without any addition of sucrose. For A. versicolor the maximum biomass of 16.03 g/L was produced at concentration of 100 g/L of sucrose however the maximum lipid content of 9.20 % was obtained at concentration of 25 g/l. GC profile for FAME composition of Aspergillus niveus on optimized synthetic medium showed higher ratios of saturated fatty acid (SFAs) (83.65%) than unsaturated fatty acid (USFAs) (9.36%). However GC profile for FAME composition of household waste media showed opposite results as high contents of USFAs (60.18%) while SFAs contents were 33.15%. GC profile for FAME composition of Aspergillus versicolor showed higher content of unsaturated fatty acids on both optimized synhetic media and household wastes media than saturated fatty acid. The total content of USFAs from optimized synthetic media was 62.62% and from household wastes media was 58.68%.