Biomass and nutrient composition of Spirulina platensis grown in goat manure media

The major costs of cultivating S. platensis are for media and labor. The aim of this study was to explore the use of goat manure as culture medium for S.platensis. A complete randomized block design was used in this study with 5 treatments of goat manure concentration, each of which was repeated 5 times. The results of the study showed that the growth of S.platensis at 25 g/L concentration of goat manure was significantly (P<0.05) lower than 50, 75, 100 g/L and Zarrouk media. S.plantesis productivity at a concentration of 25 g/L goat manure (0.128±0.011 g/L/day) was significant (P<0.05) lower than 50 (0.153±0.012 g/L/day), 75 (0.158±0.014 g/L/day), 100 g/L (0.153±0.009 g/L/day) and Zarrouk media (0.164±0.016 g/L/day). Protein content in S. platensis at 50 (59.03±4.31%), 75 (62.56±6.04%) and 100 g/L (61.22±4.54%) goat manure and Zarrouk (63.21±5.97%) media were significantly (P<0.05) higher than 25 g/L (47.35±5.16%). Lipid content in S. platensis at Zarrouk media (5.28±0.38%), 50 g/L (5.31±1.27%), 75 g/L (5.37±1.25%) and 100 g/L (5.42±1.35%) goat manure were significantly (P<0.05) lower than 25 g/L (7.86±1.16%). Carbohydrate content in S. platensis at Zarrouk (22.58±2.38%), 50 g/L (21.67±2.25%), 75 g/L (22.43±2.14%) and 100 g/L (22.67±2.38%) goat manure were significantly (P<0.05) lower than 25 g/L (27.69±1.78%). Chlorophyll content in S. platensis at Zarrouk and goat manure with 50, 75 and 100 g/L concentration were significantly (P<0.05) higher than 25 g/L (1.36±0.15%). We conclude that the concentration of goat manure 75 g/L in S.platensis cultivation media was the optimum concentration and has the potential to replace in-organic media.