RESUMO
The effects of simulated outdoor seasonal climatic conditions on Nannochloropsis salina (N. salina) grown using nutrients from anaerobic digestion (AD) effluent were evaluated in this study. Under various light exposure (LE) and temperature (10-30 °C) conditions, N. salina specific growth rate (µ) was strongly affected by LE. Light availability (LA) was observed to be crucial for biomass production, with µ values of 0.038±0.013 d(-1), 0.093±0.013 d(-1), and 0.151±0.021 d(-1) for 6-h, 12-h, and 24-h LA conditions, respectively. Temperature (10-25 °C) was not significant in affecting the light dependent growth coefficient (µ/LE), indicating the suitability of culturing this strain in the Ohio climate. Cultures exposed to low illumination had significantly higher unsaturated fatty acid content than those under high illumination, with nearly 29% higher eicosapentaenoic acid (C20:5) content. Using LE and light attenuation resulted in adequate prediction of N. salina growth in a 1000 L open raceway pond.
Assuntos
Microalgas/crescimento & desenvolvimento , Nitrogênio/farmacologia , Fósforo/farmacologia , Água do Mar/microbiologia , Eliminação de Resíduos Líquidos , Anaerobiose/efeitos dos fármacos , Anaerobiose/efeitos da radiação , Reatores Biológicos/microbiologia , Simulação por Computador , Ácidos Graxos/biossíntese , Cinética , Luz , Microalgas/efeitos dos fármacos , Microalgas/efeitos da radiação , Modelos Teóricos , Nitrogênio/análise , Fósforo/análise , Lagoas , Reprodutibilidade dos Testes , Estações do Ano , TemperaturaRESUMO
The potential use of Synechocystis sp. PCC6803 (Synechocystis sp.) for lipid production using artificial seawater (ASW) medium supplemented with anaerobic digestion effluent (ADE) was investigated and compared to marine microalgae, Nannochloropsis salina (N. salina). Synechocystis sp. showed growth rates 83% and 20% higher than N. salina at 3% and 6% ADE loading ratios, respectively, achieving the highest biomass productivity of 212 mg L(-1) d(-1) in semi-continuous cultivation. The rapid growth of Synechocystis sp. was offset by its low lipid content, resulting in lipid productivities 7-28% lower than N. salina. The lipid productivity of Synechocystis sp. may be further improved by decreasing the harvesting interval during semi-continuous cultivation. Fatty acid analysis showed that lipids extracted from Synechocystis sp. contained higher palmitic acid (60.3±2.0%) and linoleic acid (20.0±1.6%), and had a higher cetane number and oxidative stability than those from N. salina.
