Effectiveness of Biogas Production in the Process of Anaerobic Methane Co-digestion of Microalgae Biomass and Maize Silage

Development of a sustainable bioenergy market is based these days on energy crops, increased production of which competes with global food and feed supply. Consequently, there is a need to identify an alternative energy biomass of non-food plant species. The microalgae biomass offers such an alternative as it may be produced independently of farm land use. Therefore, laboratory studies (continuous reactors, mesophilic conditions) were carried out to investigate the potential of microalgae biomass as a feedstock for methane co-digestion with the energy crop Zea mays silage, with the aim to enhance biogas/methane yield. The results showed that mixing of the maize silage with microalgae biomass improved the C/N ratio when compared to the individual fermentation substrates. The highest methane and biogas production (3045 cm(3)/d and 628 cm(3)/g per dry mass, respectively) were achieved when microalgae biomass constituted 40% of the feedstock and the C/N ratio was 17.53.