engleski

Bioaugmentation of biogas producing reactors using Miscanthus grass as substrate

One of the objectives of the European framework for climate and energy policies until 2030 and the UN Climate Change Conference is to implement renewable energy sources as one of the most important element of energy self-sufficiency and for mitigating climate changes. Among others, agricultural biomass could represent a significant source of different raw materials in the “green energy” production system. The biomass can be used as a combustion fuel but also as a substrate for biogas production. Biogas is a product of microbial anaerobic digestion consisted mostly of methane and carbon dioxide and when processed, is used to power internal combustion engines. An agricultural crop, perennial grass Miscanthus is suitable to be used as substrate for biogas production due to high yield, low requirements for inputs, perenniality and cold tolerance. Aim of here presented work was to augment the bioreactors using Miscanthus as substrate for anaerobic biogas production by adding targeted microorganisms. The microorganisms were isolated from anaerobic sludge through consecutive selection steps that enabled survival of cells capable to use Miscanthus biomass as sole carbon source. The idea was to enrich biogas producing reactors with bacteria capable of enzymatic degradation of biomass. Additionally, the bacterial cells were immobilized on perlite (a natural alumosilicate mineral) particles in the form of biofilm, as to further enhance microbial activity. When added to bioreactors, the Miscanthus biomass solely increased biogas yield up to 330 %. By adding successfully isolated microorganisms in the form of suspension, the yield was further increased up to 382 % and in the form of perlite bioparticles up to 411 %. The bioparticles also showed high potential for bioreactor stabilization, enabling constant yield and potentially enabling better process efficiency. The research was financed by the OP "Competitiveness and Cohesion" 2014-2020 KK.01.1.1.07.0078 project „Sustainable biogas production by substituting corn silage with agricultural energy crops“, and by the European Commission and BBI consortium via H2020 BBI-DEMO project No. 745012 „GRowing Advanced industrial Crops on marginal lands for biorEfineries – GRACE”.

biogas ; bacteria ; perlite ; bioaugmentation

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