engleski

Microalgal cultivation on different digestate concentrations for biogas production

Microalgae, as a diverse group of microorganisms, are becoming increasingly interesting for biofuel production due to the high biomass yield rich in valuable compounds. A modern approach for microalgae cultivation could be based on combining with digestate, a by-product of anaerobic fermentation. In this way, sustainable waste management is achieved while reducing the environmental impact. This type of digestate utilization closes the production cycle and creates biomass that can be reused for further production. The aim of this research was to compare the amounts of biogas produced from the microalgae biomass, which were cultivated on different digestate concentrations. The biomass used in the research was obtained by cultivating microalgae on two different digestate concentrations of 31.06 and 53.60 mg/L. The experiment was performed in triplicate. Qualitative analysis of the obtained biomass determines the dominance of the green chlorococcal algae Coenocystis and the cyanobacteria Lyngbya. The process of anaerobic fermentation was carried out using cow manure in codigestion with the obtained biomass in thermophilic conditions (55°C) for a period of 22 days. Biogas production for experimental group were 259.74 mL/g volatile solids (VS) with biomass grown at a lower digestate concentration and 270.55 mL/gVS with biomass grown at a higher digestate concentration, accompanied by average methane concentration around 65%. Results showed no statistically significant differences in the amount of biogas obtained (Δ=10.81 mL/gVS) or in the average methane concentration (Δ=0.20%) between the researched groups. Based on the obtained results, it is concluded that different digestate concentrations used in microalgae cultivation had no significant effect on biogas production or methane concentration.

microalgae ; biomass ; biogas ; digestate ; anaerobic fermentation

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