ANAEROBIC DIGESTION OF LIGNOCELLULOSIC MATERIALS USED IN BIOGAS PRODUCTION

V diplomskem delu prikazujemo študijo vpliva predobdelave lignoceluloznih materialov z glivo Trametes Versicolor in vpliv deleža lignina v lignoceluloznih materialih na količino nastalega bioplina v procesu anaerobne digestije. Poleg tega smo preučevali stopnjo razkroja lignina po končanem procesu anaerobne digestije, časovno spremembo vsebnosti lignina v lignoceluloznih materialih obdelanih z glivo ter optimalno velikost delcev substrata za analizo vsebnosti lignina. Kot substrata smo uporabili koruzno slamo in celulignin, izoliran iz kostanja, sama ali zmešana v različnih razmerjih. Tako dobljene vzorce substratov smo predobdelali z glivo Trametes Versicolor. Za primerjavo so služili rezultati, dobljeni z uporabo neobdelanih substratov ter čiste celuloze in inokuluma. Ugotovili smo, da pri digestiji koruzne slame, same ali zmešane z celuligninom, nastane več bioplina, če le ta ni predobdelana z glivo. Pri tem je najdonosnejša kar sama koruzna slama. Pri čistem celuligninu je opažen obraten trend, in sicer je donos bioplina bistveno večji pri predobdelanem celuligninu. Rezultati kažejo, da je za analizo vsebnosti lignina najoptimalnejša uporaba substratov z delci velikosti med 2 in 2,5 mm. Vsebnost lignina se pri obraščanju materialov z glivo najprej zniža, nato po nekaj dneh sledi naraščanje, zatem ponovni pad in ponovno naraščanje.This diploma work presents a study regarding the impact of the pre-treatment of lignocellulosic materials with fungus Trametes Versicolor fungus, and the presence of lignin at different ratios, on the resulting amount of biogas produced during the process of anaerobic digestion. In addition, the degree of lignin decomposition was studied after the process had finished. Furthermore, the time-dependence of the lignin content within those lignocellulosic materials treated with Trametes Versicolor fungus was studied, together with the optimal sizes of the particles used for lignin content analysis. Corn stover and cellulignin, isolated from chestnut, alone or mixed in different ratios, were used as substrates and pre-treated with fungus Trametes Versicolor fungus. The obtained results were compared to those obtained using non-pre-treated substrates, pure cellulose and bacterial inoculum. In regard to corn stover, alone or mixed with cellulignin, it was found that more biogas was produced when they were not pre-treated with fungus, and that the highest amount of biogas was produced from pure corn stover. In the case of cellulignin – a lignin rich substrate, the opposite trend was observed, i.e. the significantly higher amounts of biogas were produced when the cellulignin was pre-treated with the fungus. The results also showed that the optimal sizes of the particles used for determining the lignin content within a lignocellulosic material, were within the range 2.0 - 2.5 mm. The time-dependence of the lignin content within in fungus pre-treated samples firstly decreased, followed by an increase after a certain time. The content then decreased once again, and finally increased