The main objective of the present research paper is to compare the amount of biogas produced from a set of experiments conducted under identical technical setting (loading rate, temperature, means of stirring, kind of substrate fed, hydraulic retention time, etc.), using orthofruit waste but different bacteria inoculums. Methane concentration in the biogas, total COD and volatile solids removal, are another important parameters observed. In addition, in order to improve the quality of the biogas produced, adsorption unit added to the plant was used to enrich methane composition in the biogas produced. The results obtained from two runs performed at different flow rates, are also discussed in the present paper.