Abstract
A biocultivator (photobioreactor) has been developed for large-scale production in arid regions using the diatom Skeletonema costatum. The product is used for the larviculture of aquaculturally important marine food organisms. This system was operated in India with a total solar collection area of 560 m super(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 feeble aeration to prevent distortion and rupture of the long-forming chains. Growth in this system with organic nutrients showed the following relationship between cell number (Y) and culture time in hours: 7( chi ): Y = 0.03699 sub( chi ) -0.1540 Under vertical mixing, a high and low cycle of solar energy irradiance attenuated exponentially just beyond the 1.5-m light path, while areal productivity levelled off at 60 g C m super(-3) d super(-1). This large-scale approach is appropriate for factory-scale production of cost-effective unialgal Skeletonema (US $ 0.067 kg super(-1) dry matter).