Optimization model for cultivation of green alga, Desmodesmus quadricauda as feedstock for biodiesel production

Abstract

Optimization model for cultivation of green alga, Desmodesmus quadricauda as feedstock for
biodiesel production was performed by screening 7 factors which affected to biomass and lipid production
of this alga. The factors; KNO3
, KH2
PO4
, Fe, NaCl, light intensity and CO2
had significant positive effect
to this alga. The optimization model by using central composite design (6 factors) for lipid production of
this alga was: Y (lipid) = 0.0038 + (0.0066 KNO3
)+ (0.0028 KH2
PO4
) – (0.0130 Fe) + (0.0002 NaCl) – (0.0020
CO2
)- (0.0029 KNO3
*KNO3
) + (0.0007 KH2
PO4*KH2
PO4
) + (0.3070 Fe*Fe) + (0.0001 CO2
*CO2
) + (0.0006
KNO3
*KH2
PO4
) + (0.0133 KNO3
*Fe) + (0.0001 KNO3
*light intensity) + (0.0005 KNO3
*CO2
) + (0.0005
KH2
PO4
*Fe) – (0.00001 KH2
PO4
*NaCl) – (0.0001 Fe* CO2
).The optimum factors for biomass and lipid
production by response surface method were 2.44 g/L of KNO3
, 2.44 g/L of KH2
PO
4, 0.12 g/L of Fe, 20.87
g/L of NaCl, light intensity 82.52 µE/m-2/s and 6.09 % of CO2
which provided 1.34 g/L of biomass, 0.06
g/L/d of biomass production rate, 1.02 g/L of lipid yield, and 0.13 g/L/d of lipid production rate.