Abstract: This work was based on the pretreatment of lingo-cellulosic wastes from agro – forestry organic wastes with samples being taken from stations of different sources. Between many of recommended and explained methods for pretreatment of the organic biomass we selected as the most effective, the way of acidic waste pretreatment and another scenario applying the alkaline method prior to the biodegradation through anaerobic bio-digestion for energy profit. For bio-methane profit process has been performed in a series of the experiments. From the various experiments we realized the great importance of the pre-treatment process for the biogas production. Alkaline pretreatment (with NaOH) brought about a decay of lignin structure of biomass and increase access of enzymes in hemicellulose and cellulose. This method was more effective than acidic treatment due to the fact that was achieved more dissolved lignocellulose, which is indicated by the highest decrease of organic material in the treated samples. To increase the acid concentration, it increases also the disintegration of lignocellulosic material. This is because with the increase of acid (H₂SO₄) concentration, enables separation of organic connections in walls of lignine, enabling easier attacking hemicellulose and cellulose. We were focused more on the acidic and alkaline pretreatment and on the development of experiments, analysis of raw materials, taking samples before and after appropriate pretreatment. Surveillance and identification of changes occurring during pretreatment processes has been conducted for a certain period of time and the important conclusion has been taken.
Keywords: biomass, organic waste, anaerobic digestion, alkaline and acidic pretreatment