An industrial photosynthetic system for Skeletonema costatum in arid regions

A biocultivator has been developed for large-scale production in arid regio ns using the diatom Skeletonema costatum. The product is used for the larvi culture of aquaculturally important marine food organisms. This system was operated in India with a total solar collection area of 560 m(2). Operating under a batch regime, this slow-mixing open reactor has a long light path. Starter cultures were supplied from a polythene bag hung in the air with f eeble aeration to prevent distortion and rupture of the long-forming chains . Growth in this system with organic nutrients showed the following relatio nship between cell number (Y) and culture time in hours (chi): Y = 0.03699 chi - 0.1540 Under vertical mixing, a high and low cycle of solar energy irradiance atte nuated exponentially just beyond the 1.5-m light path, while areal producti vity levelled off at 60 g C m(-3) d(-1). This large-scale approach is appro priate for factory-scale production of cost-effective unialgal Skeletonema (US $ 0.067 kg(-1) dry matter).