The medium for intensive culture of the diatom Cylindrotheca closterium (Ehrenb.) Reimann et Lewin (Bacillariophyta)

The proposed medium was developed specially for intensive culture of the diatom Cylindrotheca closterium (Ehrenb.) Reimann et Lewin. The averages of nitrogen, phosphorus, and silicon demand for the culture were calculated using the data from the chemical analysis of the microalgal biomass. Growth limitation by nitrogen provoked agglutination of the microalgal cells. High concentrations of iron did not inhibit the growth rate of C. closterium. Organic nitrogen present in the medium can be due to biosynthesis of exometabolites. During the stationary growth phase, the total and organic nitrogen in the medium were evaluated 28 mg times L super(-1) and 17.8 mg times L super(-1), correspondingly. The average loss of nitrogen in the culture was estimated at 10 %. The maximal dry biomass harvested from the diatom was 4.6 g times L super(-1) and the productivity -- 1 g times L super(-1) times d super(-1). The new medium allows growing dense cultures of C. closterium with a larger biomass and therefore a proportionally larger yield of valuable biologically active substances, e.g. polyunsaturated fatty acids and carotenoids, primarily fucoxanthin.