Abstract
Microalgae are a potential source of biodiesel. Isolates of the present study were isolated from Wadi-henifa, Rhiyad, Saudi Arabia. The urgent need for an alternative and sustainable energy has created renewed interest to analyse the microalgae for biodiesel production. The greatest lipid content reached 20.2, 16.4, 9.7 and 12.3 To under the optimal conditions of nitrate concentration (0.75 g/l), temperature (24 and 30 degrees C), salinity (0.05 and 0.001 mole/l) and pH (8 with Chlorellavulgarus and 9 with other strains), Chlorella vulgarusArthrospiraplatensisGomont and Spirulina major, respectively. It was demonstrated that the obtained model was effective for predicting lipid productivity of the isolated microalgae. The maximum protein content was at 24 degrees C for Chlorella vulgarus,ArthrospiraplatensisGomont and Spirulinamajorkutz, (53, 56.8 and 54 % respectively), while the maximum protein content of Arthrospira maxima was at 30 degrees C (56.2 %).The optimum protein content was found at pH9 for Arthrospiraplatensis Gomont, Spirulina major kutzand Arthrospira maxima(48.47, 55.47 and 63.25 % respectively) while in case of Chlorella vulgarus was at pH 8 (51 %).The maximum protein content was 76.96 To at 0.001 mole Nacl/L, 54, 75.38 and 75.09 % at 0.05 mole/L for Chlorella vulgarus,Spirulina major kutz, Arthrospira maxima and Arthrospiraplatensis Gomont respectively. Results of this study revealed thatthe mention optimization conditions enhanced protein content of the tested isolates. ArthrospiraplatensisGomont, Spirulinamajor kutzand Arthrospira maxima are promising organisms with high nutritional value for animal and human beings.