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Aims: Variation in the traditional growth medium conditions to enhance the production of lipids, carbohydrates, protein and the free amino acids content of three cyanobacterial species. Methodology and Results: Three species of cyanobacteria (Anabaena laxa, Anabaena fertilissima and Nostoc muscorum) were collected from the culture collection of Soils, Water and Environment Research Institute, Agriculture Research Center, Giza, Egypt, to investigate their biochemical composition under different growth conditions, using BG110 (nitrogen free) as growth medium. These conditions were represented by control medium, static glucose medium with (1%, w/v), aerated medium (aerated by bubbling technique depending on CO2 normally existed in air with a concentration of 0.03%), molasses medium (0.7%, v/v) and aerated medium enriched with glucose (1%, w/v). Lipid content, total carbohydrates, soluble proteins and free amino acids were determined at the previous conditions. Glucose at 0.7% (w/v) was the most favorable for lipid production in A. laxa, where it exhibited the highest lipid content (427 µg/g fresh wt.). Increasing molasses concentration up to 0.7% (v/v) produced an increase in lipid contents of the tested cyanobacterial strains. The highest lipid content of both N. muscorum (366.2 µg/g fresh wt.) and A. laxa (357.4 µg/g fresh wt.) were recorded at molasses concentrations of 0.1 and 0.7% (v/v), respectively. A. laxa expressed high significant values for both proteins (31.6 µg/mL) and free amino acids (40.5 mg/g dry wt.) after 6 days of incubation period under aerated enriched glucose condition (1%, w/v). Also, at the same growth conditions, A. fertilissima exhibited high significant values for carbohydrates at 4 th day (876.8 mg/g dry wt.). Conclusion, significance and impact of study: Aerated enriched glucose medium (1%, w/v) was the best growth medium condition used in the present study.

A field experiment was conducted in sandy soil at Ismailia Agricultural Research Station, (Ismailia Governorate, Egypt, in two successive winter seasons of 2015/2016 and 2016/2017. The experiment aimed to study the response of lupine plants (Lupinus albus L.) variety Giza 2 to cyanobacteria applied with different methods under different nitrogen fertilizer rates and inoculated with rhizobia. Results revealed that application of cyanobacteria generally increased the mean values of nodules number, dry weight of nodules and shoot dry weight of lupine plants, nitrogen uptake, biological activity of the soil rhizosphere lupine plants, yield, yield components and seed protein content as compared to those recorded by the control treatment without cyanobacteria. Increasing nitrogen rates decreased the mean values of both nodules number and dry weight of nodules. On the contrary, increasing nitrogen rate up to 100% of the recommended one increased all the other tested parameters. The highest values of these parameters were recorded when cyanobacteria were applied as dry + soaking combined with 75 % N rate expect for those of number and nodules the dry weight of nodules that gave their highest values when the lupine plants received the treatment of dry + soaking combined with 50 % N rate. In conclusion, the use of cyanobacteria along with rhizobia as renewable nitrogen source for lupine production can save 25% N from that required for lupine.

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