Kinetic model of Chlorella vulgaris growth with and without extremely low frequency-electromagnetic fields (EM-ELF).
Chlorella vulgaris was grown in two bench-scale photobioreactors with and without the application of a low intensity, low frequency electromagnetic field (EM-ELF) of about 3mT. Cell concentration and tendency of cells to form aggregates inside the reactor were recorded over a 30 days-time period at 0.5L-constant medium volume in the temperature range 289-304K. At 304K, after a cultivation period of 15 days, the rate of cell death became predominant over that of growth. In the temperature range 289-299K, a two step-kinetic model based on the mitotic division and the clusterization processes was developed and critically discussed. The best-fitted curves turned out to have a sigmoid shape, and the competition between mitosis and clusterization was investigated. Without EM-ELF, the temperature dependence of the specific rate constant of the mitotic step yielded an apparent total enthalpy of 15±6kJmol(-1), whose value was not influenced by the EM-ELF application. The electromagnetic field was shown to exert a significant effect on the exothermic clusterization step. The heat exchange due to binding between cells and liquid medium turned out to be -44±5kJmol(-1) in the absence of EM-ELF and -68±8kJmol(-1) when it was active. Optical microscopy observations were in agreement with the model predictions and confirmed that EM-ELF was able to enhance cell clusterization.
Department of Civil, Chemical and Environmental Engineering (DICCA), Laboratory of Material Sciences, University of Genoa, Piazzale Kennedy, Fiera del Mare, I-16145 Genoa, Italy. Electronic address: dabe@unige.it.
Dario T
DT
Beruto
Department of Civil, Chemical and Environmental Engineering (DICCA), Laboratory of Material Sciences, University of Genoa, Piazzale Kennedy, Fiera del Mare, I-16145 Genoa, Italy.
Alberto
A
Lagazzo
Department of Civil, Chemical and Environmental Engineering (DICCA), Laboratory of Material Sciences, University of Genoa, Piazzale Kennedy, Fiera del Mare, I-16145 Genoa, Italy.
Davide
D
Frumento
Department of Civil, Chemical and Environmental Engineering (DICCA), Laboratory of Material Sciences, University of Genoa, Piazzale Kennedy, Fiera del Mare, I-16145 Genoa, Italy.
Attilio
A
Converti
D002455:Cell Division; D048408:Chlorella vulgaris / Q000254:growth & development* / Q000648:ultrastructure; D004574:Electromagnetic Fields; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological
Chlorella vulgaris; Clusterization; Low frequency electromagnetic field; Low intensity; Mitotic division