Smart Production of Lipids as Bio-Fuel in Spirulina Platensis (=Arthrospira Fusiformis), and Bio-Oxygen and Bio-Electricity in Media Cultured in Supernatant of Digested Poultry Waste

Abstract :

An experiment was conducted to evaluate growth performances and production of bio-fuel of Spirulina platensis (Gomont), and bio-oxygen and bio-electricity of culture media in supernatant of three different amount of digested poultry waste (DPW), and Kosaric medium (KM) as control. Three different amounts (concentrations) such as 2.0, 4.0 and 6.0 g/L poultry waste were allowed to digest under aeration. After 17 days, 700 ml grayish coloured supernatant was taken with addition of 9.0 g/L NaHCO3 and 0.50 ml/l micronutrient in 2.0 L conical flask with three replications and then autoclaved. Spirulina was inoculated to grow in these three treatments including KM (Control) after 72 hours of autoclave and then allowed to grow for a period of 14 days. This duration was estimated through repeated growth trials. The cell weight of spirulina was attained a maximum of 12.58 ± 1.25 mg/L (dry wt. basis) in KM followed by 11.46 ± 1.03, 9.16 ± 0.84 and 8.13 ± 0.73 mg/L in supernatant of 4.0, 2.0 and 6.0 g/L DPW, respectively on the 10th day of culture. Similar trend was also observed in the cases of optical density of the media contained spirulina, chlorophyll a content (mg/L), cell weight, total biomass (mg/l) and specific growth rates on the basis of cell weight and chlorophyll a. Cell weight of spirulina grown in these media had highly significant (P < 0.01) correlation with the chlorophyll a content (r = 0.993) of spirulina. Crude protein of spirulina grown in supernatant of DPW was lower than that of spirulina cultured in KM. Crude lipids as bio-fuel of spirulina cultured in supernatant of 4.0 g/L DPW was almost three times higher than that of spirulina grown in KM which may be due to high phospholipids bioaccumulation. Phosphate-P was decreased in media of DPW due to its use for high lipids biosynthesis as phospholipids. Bio-oxygen was produced higher ranged from 2.1 ± 11 mg/L on initial day to 10.20 ± 0.54 mg/L on 10th day grown in supernatant of 4.0 g/L DPW media. Bio-electricity as green electricity ranged from 135 ± 4 on initial day to 284 ± 7 mV on 10th day when spirulina cultured in supernatant of 4.0 g/L DPW which was higher than grown in other media. pH followed the similar trend like bio-oxygen and bio-electricity. It was found that the production of bio-oxygen, bio-fuel and bio-electricity had direct relation with pH in culture media of spirulina. Therefore, mass production of Spirulina platensis might be done in supernatant of 4.0 g/L digested poultry waste to get high total lipids as bio-fuel, bio-electricity and bio-oxygen.