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Influence of growth kinetics of microalgal cultures on biogas production

Córdova, O., Ruiz-Filippi, G., Fermoso, F.G., Chamy, R.
Renewable energy 2018 v.122 pp. 455-459
biogas, biomass, energy balance, growth curves, growth models, harvesting, logit analysis, methane, microalgae, physicochemical properties
The microalgal cultures growth curve shows different phases involving changes in the physical-chemical characteristics of the microalgae. The aim of this study was to determine if the physico-chemical differences involve different biogas productions during the different stages of growth kinetics of C. sorokiniana. The microalgae growth kinetics was evaluated in batch cultures. Three phases were differentiated on the growth curve: P1, beginning of the exponential growth; P2, end of the exponential growth, and P3, steady state phase. The physico-chemical characterization, the biochemical methane potential, the biogas production rates by the Gompertz model, and the energy balance for each one of the three phases of the growth curve were evaluated. Significant differences were established in the four parameters evaluated. The highest biogas production and maximum production rate was obtained at the end of exponential growth P2, with 322 mL CH4/g VS and 17.6 mL CH4/g. VS/d, respectively. Regarding the energy balances, the methane potential from the biomass harvested in P2 and P3 phases contributed with 16% and 14% of the harvesting requirements, respectively.