3.3. Energy efficiency of gaseous biofuel from plant biomass
Based on obtained results, the mixtures for fermentation were prepared. In determining how much substrate and seeding sludge should be weighed into a fermentation batch, the general constraints from VDI 4630 were compiled. In each experiment the ratio of inoculum to substrate was 0.5 (in dry matter). Fermentation proceeded with expected dynamics and no inhibition was noticed. The results of fermentation tests are presented in Table 4 and Fig. 3. Those results were compared with the fermentation parameters of most popular substrate for biogas plant in Europe − maize silage and, additionally, with sorghum – a substrate that becomes more popular within last years (Amaducci et al., 2016).