Laboratory - scale high density culture of the marine diatom Chaetoceros sp.

Abstract

A laboratory scale continuous and semi-continuous system for culture of themarine diatom Chaetoceros sp. was devised. Using 2.5 times the normal nutrientconcentration and limited supply of Co2, the culture density could beincreased from an average 1.5 million cells / ml concentration in traditionalbatch culture systems to 13.7 million cells/ml in continuous system. Besides theincreased biomass production, the duration of culture was enhanced to thirtydays without crashing. The semi-continuous system was up-scaled to 60 1 capacitywith an internal illumination system to yield 528 litres of average 3.2million cells/ml within 36 days. The velocity of cell growth during the logarithmicphase in doublings/day ranged from 0.21 in control (batch culture) to 2.51in the semi-continuous system. Furthermore, the cost of production, even withadditional inputs, are comparable or even less than the traditional batch cultures.The economic efficiency was highest in continuous systems as comparedto semi-continuous systems (Rs. 0.03 and 0.017/billion cells as against Rs. 0.082and 0.037/billion cells).