چكيده به لاتين
Anaerobic digestion includes four stages of hydrolysis, acidogenesis, acetogenesis, and methanogenesis, in which a consortium of microorganisms hydrolyze organic materials under oxygen-free conditions into sugars, amino acids, and fatty acids, and the final product is methane. Since the understanding of the metabolic pathways of this process plays an important role in the yield of methane production as a valuable product, in this research, product production and growth were investigated using two widely used analyzes FBA and FVA in single models of clostridium acetobutylicum, Syntrophomonas wolfei and Methanospirillum hungatei. In order to simulate the three stages of acidogenesis, acetogenesis and methanogenesis in the process of anaerobic digestion, the results of the communities were analyzed. Then two and three member societies were formed by SteadyCom algorithm and COBRA toolbox in MATLAB software. The two-member community model consisting of bacteria C. acetobutylicum and M. hungatei include 256 reactions and 231 metabolites and the three member community model consisting of C. acetobutylicum, S. wolfei and M. hungatei bacteria includes 378 reactions and 344 metabolites. The effect of various factors such as the intensity of consumption of carbon material, the type of carbon source including glucose and glycerol, limiting the production of methane on these communities by FBA was investigated for the growth rate of the community and the production of products. The results of the individual models showed that in C. acetobutylicum and S. wolfei, biomass production with carbon sources of glucose and butyrate was 0.56 and 0.095 h-1, respectively, and for the M. hungatei model with carbon sources of formate and acetate. From 0.0037 to 0.14 h-1 was obtained, which indicates that glucose is more effective on growth. Methane production also varied from 2.42 to 11.95 mmol/gDW/h according to the limitations of the M. hungatei model. According to the results obtained from the communities in general, the maximum growth rate of the three-member community was higher than the two-member community, and the maximum methane production in the two-member community mmol/gDW/h was much higher than the three-member community 4.44 mmol/gDW/h was done in the condition that the biomass of all members is produced, and the amount of methane produced in the community of three members was produced by fixing the output methane flux up to 140 mmol/gDW/h. Also, methane output from the system in the presence of glycerol and glucose was 16.6 and 11.4 mmol/gDW/h, respectively, which indicates that glycerol is better than glucose as a carbon source, and the aim of this study is to increase the amount methane output in anaerobic digestion community.
