الفهرس 
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Abstract
This work based on two principal points, the first was to optimize growth condition of cyanobacterial species isolated from different Egyptian rice soils, in order to maximize their lipid content. The second point was extraction of produced lipid material and converting it into biodiesel via transestrification process. The most important results can be summarized as the following:
1- A survey was carried out on different ten cyanobacterial isolates were isolated from Egyptian rice soils under autotrophic and mixotrophic growth condition using D-glucose (1%, w/v), the capacity for lipid, biomass, organic carbon and nitrogen production of these tested and the most lipids and biomass, producer was selected for this study.
2- All tested algal spp succeeded to grow under auto and mixotrophic growth condition except A. variabilis Kützing.
3- mixotrophic growth condition led to increasing both lipids, biomass, and organic carbon content and decreasing total nitrogen for almost tested algae.
4- The highly lipids, biomass, organic carbon were A. flos aquae, A. laxa, A. fertilissima and N. Muscorum.
5- A trial was made using different glucose and molasses of sugar cane concentrations (0, 0.1, 0.3, 0.5, 0.7, 1%).focusing into lipid productivity of selecter four algae.
6- The gradual incresing of glucose in the culture medium was accompaned with gradual increasing of total lipid content till (1% w/v) for A. flos aquae, A. fertilissima and N. muscorum.except for A. laxa where, maxium lipid content was under (0.7% w/v).
7- In addition The gradual incresing of molasses in the culture medium was accompaned with gradual increasing of total lipid content till (0.7%, v/v) for A. flos aquae, A. laxa and A. fertilissima.In contrast N. muscorum coudn’t withstand concentrations more than (0.1%, v/v).Meanwhile at (1%, v/v) both A. flos aquae and A. fertilissima coudn’t grow and lipids content of A. laxa have been significantly retarded.
According to obtained data, an experiment was designed using the selected four cyanobacterial strains and subjecting them under five different growth conditions belonging to Autotrophic and mixotrophic, namely
1- Control medium.
2- Aerated medium depending on CO2 exists in air 0.04%.
3- Static glucose medium enriched with D-glucose (1% w/v).
4- Molasses medium (enriched with 0.7% v/v).
5- Aerated enriched glucose medium (1% w/v).
Certain growth parameters were evaluated including dry weight, chlorophyll (a), rate of lipid synthesis, lipids, soluble protein, soluble sugars, insoluble sugars, fatty acids, free amino acids content under different incubation periods. The most important results can be summarized as the following:
1- Mixotrophic growth condition enhance almost of growth parameters compared to autotrophic condition where, the highest dry weight was to A. flos aquae under aerated enriched glucose medium followed by static glucose treatment.
2- The maximum chlorophyll (a) content for both A. flos aquae and A. fertilissima under static glucose medium whereas, Aerated medium achieved high values for A. laxa.
3- The highest rate of lipid synthesis was achieved for A. laxa and N.mucorum whearas, aerated enriched glucose recorded highest rate of lipid synthesis for A. fertilissima and A. flos aquae, in contrast the lowest rate was due to aerated medium.
4- Mixotrophic growth condition greatly enhanced lipids production for the tested species where, the highest lipid content for A. fertilissima and A. flos aquae was achieved under aerated enriched glucose medium while the highest lipid content for A. laxa under static glucose medium.
5- Type and amount of fatty acids varied according growth condition where, percent of saturated fatty(C12:0-C14:0 -C20:0- C18:0- C16:0) acids greatly increased at the expence of mono and poly unsaturated fatty acids under mixotrophic conditions. A. fertilissima recorded the highest percent of saturated fatty acids under static gluscose medium, while A. laxa exhibited the highest percent of unsaturated fatty acids under static gluscose medium and Palmito Oleic fatty acids (C16:1)was the most common.
- Mixotrophic growth condition largely increased amount of both soluble and in soluble sugars in the algal biomass compared to autotrophic condition where, aerated enriched recorded the highest values of both soluble and in soluble sugars where A. fertilissima showed a highly significant values.
- Mixotrophic growth condition largely increased amount of soluble proteins compared with autotrophic growth condition, while A. flos aquae and A. laxa achieved significant values under aerated enriched glucose medium. And A. laxa exhibited the highest significant values of proteins compared to other tested spcies.
- Mixotrophic growth condition largely increased amount of free amino acids. where A. laxa exhibited the highest significant values of free amino acids compared to other tested spcies.
- As a result of the obtained data A. flos aquae was selected to produce lipid materials, this is due to it recorded the highest biomass and highly lipid content in addition highly proportions of Palmitoleic and Olic fatty acids under enriched glucose medium. Therefore, A. flos aquae was selected for lipid materials production.
- Some chemical analysis were carried out for the lipid materials of A. flos aquae. The analysis were saponification value, iodine number and acid value.
The lipid material exhibited moderate saponification values, low iodine number and high acid value.
- Certain chemical analysis were carried out for the produced fatty acid methyl ester (FAMEs). These analysis was density, sulfer content, total acid number, calorific value and GLC analysis.
-FAMEs exhibited low density, free of sulfur, high acid number and pleasant calorific value compared with petrodiesel.
The GLC analysis exhibited the Palmitoleic methyl ester was the most predominant followed by Palmitate methyl ester(C17H34O2).
- Cyanobacteria may be act as good candidate for biodiesel production producing cheaper friendly biofuel.