Abstract
Dunaliella salina is well-known for its ability to accumulate high amounts of carotenoids when cultivated under high salinity and high irradiance. However, as with all microalgae, cultivation processes are expensive when synthetic fertilizers are used for cultivation. In this study, we assessed the feasibility of utilizing anaerobic digestate of food waste as a source of nitrogen for the cultivation. Dunaliella salina MUR 8 was cultivated in F-medium with partial to complete replacement of the nitrogen (0–100% digestate nitrogen) source under high salinity (150–250‰) conditions to study both cell growth and carotenogenesis. Further investigation of the physiological response of D. salina was performed under varying irradiance and temperature levels. Maximum growth rate of 0.141 ± 0.022 day−1 and carotenoid content of 3.53 ± 0.47 mg g−1 were achieved at 150‰ salinity and under mild irradiance of 180 µmol photons m−2 s−1, in medium where nitrogen was completely replaced with food waste digestate nitrogen. Higher irradiance above 400 µmol photons m−2 s−1 and higher salinity had combined negative effects on growth and carotenogenesis, reducing growth rate and carotenoid content to 0.047 ± 0.01 day−1 and 1.797 ± 0.37 mg g−1, respectively, due to the NH3–N species present in the digestate. However, under increased irradiation and temperature, in comparison with cultures grown in synthetic medium with nitrate salts as nitrogen source, there was no significant difference in biomass productivity when the strain was cultivated using food waste digestate as sole nitrogen source.
Original language | British English |
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Pages (from-to) | 101-112 |
Number of pages | 12 |
Journal | Journal of Applied Phycology |
Volume | 34 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2022 |
Keywords
- Carotenoids
- Dunaliella salina
- Food waste digestate
- Nitrogen source
- Photosynthesis