Influence of ammonium chloride feeding time and light intensity on the cultivation of Spirulina (Arthrospira) platensis

Abstract

This study dealt with the influence of both the feeding time and light intensity on the fed-batch culture of the cyanobacterium Spirulina (Arthrospira) platensis using ammonium chloride as a nitrogen source. For this purpose, a 2(2) plus star central composite experimental design combined with response surface methodology was employed, and the maximum cell concentration (X(m)), the cell productivity (P(X)), and the yield of biomass on nitrogen (Y(X/N)) were selected as the response variables. The optimum values of X(m) (1,833 mg L(-1)) and Y(X/N) (5.9 g g(-1)) estimated by the model at light intensity of 13 klux and feeding time of 17.2 days were very close to those obtained experimentally under these conditions (X(m) = 1,771 +/- 41 mg L(-1); Y(X/N) = 5.7 +/- 0.17 g g(-1)). The cell productivity was a decreasing function of the ammonium chloride feeding time and a quadratic function of the light intensity. The protein and lipid contents of dry biomass collected at the end of cultivations were shown to decrease with increasing light intensity.

Kinetic and thermodynamic investigation of Arthrospira (Spirulina) platensis fed‐batch cultivation in a tubular photobioreactor using urea as nitrogen source

“…• C, U = 1.879 mmol L −1 d −1 ) was the likely result of partial loss of urea as ammonia during cultivation, 38 favored by the relatively high temperature, hence the consequent limitation of growth (X m = 2201 mg L −1 ). As pointed out in previous work carried out in open pond with the same nitrogen source, the adoption of a temperature significantly higher than the optimum for the A. platensis strain employed in this study (29 • C) 15 could have been responsible for thermal inactivation of the growth like that observed for other microorganisms.…”

“…To this purpose we used the statistical methodology described in the Materials and methods section. However, the optimization of X m required an expansion of the experimental design as suggested by Fratelli et al 43 and Bezerra et al 38 ; therefore, additional experiments (runs 12-23) were carried out, whose results are illustrated in Fig. 2 and summarized in Table 1, part B.…”

GROWTH AND COMPOSITION OF Arthrospira (Spirulina) platensis IN A TUBULAR PHOTOBIOREACTOR USING AMMONIUM NITRATE AS THE NITROGEN SOURCE IN A FED-BATCH PROCESS

“…In conventional cyanobacteria cultivation, nitrate salts (sodium and potassium nitrates) are the most used nitrogen sources, and several studies have demonstrated the feasibility of replacing these conventional nitrogen sources with low-cost alternatives such as urea, ammonium sulfate and ammonium chloride Bezerra et al, 2008;Matsudo et al, 2012;Ferreira et al, 2010;AvilaLeon et al, 2012). Depending on the purpose of cultivation (e.g., pigments, carotenoid, fatty acids, biomass), different variables may be controlled in the growth of A. platensis.…”

“…For example, the quantity and quality of the nitrogen source have a significant effect on the biomass yield and quality (Piorreck et al, 1984;Danesi et al, 2002;Avila-Leon et al, 2012). Under alkaline conditions, such as those usually adopted in S. platensis production, ammonium salts are in part present in the medium as ammonia, which is volatile and can even be toxic to the microorganism, depending on its concentration (Abeliovich & Azov, 1976;Muro-Pastor & Florencio, 2003;Bezerra et al, 2008). Even when urea is used as a nitrogen source, ammonia is formed either by its hydrolysis under alkaline conditions (Danesi et al, 2002) or by urease activity (Shimamatsu, 2004).…”

“…Spirulina platensis can be cultivated by batch, continuous, semicontinuous (Reichert et al, 2006) and fed-batch processes . The latter process, when conducted at both a suitable feeding time and feeding rate to supply the nitrogen source according to A. platensis demand, can avoid any inhibitory ammonia concentration in the medium (Bezerra et al, 2008;Carvalho et al, 2004;Matsudo et al, 2009). Ammonium nitrate provides the culture with a readily assimilable nitrogen source (ammonia) and one reserve nitrogen source (nitrate) because ammonia is the preferred type of nitrogen for S. platensis (Boussiba, 1989).…”