Growth Performance and Production Cost of Commercial Microalgae Cultured under Laboratory Conditions with Different Aeration Setting

Abstract

Microalgae such as the diatom Chaetoceros calcitrans, the green algae Chlorella spp. and the flagellate Isochrysis galbana, are commonly used as  important live food for crustacean, fish and bivalve larvae in Thailand. There by they have been product commercially. In this study, the growth performance and production cost of commercial microalgae cultured under laboratory conditions with different aeration settings (24, 12, 8 and 6 hrs per day) were investigated. Algae were cultured in enriched seawater (28 ppt) in 1 L glass bottles using Conway medium. Microalgae were grown in a temperature-controlled room (25 ^oC) under continuous illumination at a light intensity of about 3,000 Lux, for 10 days. Results showed that the growth rate of Chaetoceros culture grown with 24, 12 and 8 hrs aeration settings were not significantly different (P>0.05), but were significantly higher at the  6 hrs aeration setting (P<0.05). In addition, the growth rate of Chlorella and Isochrysis in each treatment were not significantly different (P>0.05). Commercial Chaetoceros produced with 24 hrs aeration setting had a significantly higher production cost (P<0.05) compared with those produced with 12, 8 and 6 hrs aeration settings. In addition, at 12, 8 and 6 hrs aeration settings, Chaetoceros production cost could be reduced by 7.96, 14.08 and 20.91%, respectively. Therefore, an alternative option for commercial microalgal production is to set an optimal aeration setting to achieve better profit margin and higher production.