Enhancement of the carbohydrate content in Spirulina by applying CO, thermoelectric fly ashes and reduced nitrogen supply.

This study focused on evaluating whether the injection of CO, which is associated with the use of thermoelectric fly ashes and a reduced supply of nitrogen, affects the production of intracellular carbohydrates from Spirulina. For this purpose, the addition of 0.25 g L of NaNO, along with a 10% (v v) of CO injection, a flow rate of 0.3 vvm for 1 or 5 min, as well as 0, 120 and 160 ppm of fly ashes, was studied. The assays with 120 ppm of fly ashes presented the best kinetic parameters and CO biofixation rate, regardless of the CO injection time. Meanwhile, the experiments with 120 and 160 ppm of fly ash and CO injection for 1 min presented 63.3 and 61.0% (w w) of carbohydrates, respectively. Thus, this study represents an important strategy to increase the accumulation of carbohydrates in Spirulina, with potential application in the production of bioethanol.