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

Abstract

Kinetic and thermodynamic investigation of Arthrospira (Spirulina) platensis fed-batch cultivation in a tubular photobioreactor using urea as nitrogen source JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY, HOBOKEN, v. 87, n. 11, pp. 1574-1583, NOV, 2012 BACKGROUND: Fed-batch culture allows the cultivation of Arthrospira platensis using urea as nitrogen source. Tubular photobioreactors substantially increase cell growth, but the successful use of this cheap nitrogen source requires a knowledge of the kinetic and thermodynamic parameters of the process. This work aims at identifying the effect of two independent variables, temperature (T) and urea daily molar flow-rate (U), on cell growth, biomass composition and thermodynamic parameters involved in this photosynthetic cultivation.

Ferric chloride flocculation plus carbon adsorption allows to reuse spent culture medium of Arthrospira platensis

“…have lipid contents of 6–13%, and almost half of the lipids are fatty acids . As was expected, the lipid values in A. platensis are almost unchanged by the experimental conditions . The total amounts of lipid contents reached in this study (7.0–8.4%) are similar to the lipid value (7.2%) shown by Rafiqul et al , who used sodium nitrate as nitrogen source in Erlenmeyer flasks to investigate the best conditions of pH, light intensity, and temperature in the cultivation of Spirulina spp.…”

“…In this work, starting the response surface methodology (RSM) with the experimental results of Tests 1–19 (Table —part A) led to an optimal condition of T impossible to apply experimentally. For this reason, it was necessary to expand this initial experimental design to include two additional tests (Tests 20 and 21; Table —part B) to further optimize T values. Confirmation experiments (Tests 22–24; Table —part C) were carried out with the optimal values of GAC , F , and T estimated by mathematical models from multivariable regression analyses, with the X m values listed in parts A and B of Table .…”

“…The culture broth was maintained in a rotator shaker at 100 rpm and a continuous light intensity of 120 μmol photons m −2 s −1 as in Section . The temperature was fixed at 32 ± 1°C by regulating the room temperature at 28 ± 1°C. During A. platensis cultivation, pH was maintained at 9.5 ± 0.2 by CO 2 daily addition from a cylinder.…”

“…The culture broth was maintained in a rotator shaker at 100 rpm and a continuous light intensity of 120 μmol photons m −2 s −1 as in Section 2.1. The temperature was fixed at 32 ± 1°C [13,18] a) X 1 = codified values of granular activated carbon concentration (GAC). b) X 2 = codified values of ferric chlorate concentration (F).…”

Simultaneous use of sodium nitrate and urea as nitrogen sources improves biomass composition of Arthrospira platensis cultivated in a tubular photobioreactor

“…where m i and m t2 are the quantities of urea added per unit reactor volume at the start and at instant t (day), respectively, and k (1/day) is an exponential time constant [24]. Total feeding time (T, day) was 7 days [14]. Starting quantity of urea (m i ) was experimentally set at 400 mg.…”