In situ Carbon Supplementation in Large-scale Cultivations of Spirulina platensis in Open Raceway Pond

摘要

The objective of this study was to estimate the CO_2 absorptivity provided by an in situ carbon supply system using a photosynthetic culture of the cyanobac-terium Spirulina platensis in an open raceway pond. The effects of initial total carbon concentrations (ranging from 0 to 0.1 mol/L), suspension depths (ranging from 5 to 20 cm) and Ph values (ranging from 8.9 to 11.0) on the CO_2 absorptivity were studied. The results indicated that CO_2 absorptivity was positively correlated with Ph value, negatively correlated with total carbon concentration, and only negligibly affected by the suspension depth. The optimum total carbon concentration range and Ph range were 0.03 ～0.09 mol/L and 9.7～10.0, respectively. An average CO_2 absorptivity of 86.16% and average CO_2 utilization efficiency of 79.18% were achieved using this in situ carbon-supply system in large-scale cultivation of Spirulina platensis, with an initial total carbon concen-tration of 0.06 mol/L and Ph value of 9.8. Our results demonstrated that this system could obtain a favorable CO_2 utilization efficiency in outdoor, large-scale cultivation of Spirulina platensis in open raceway ponds.