Development of balanced community of microorganisms is one of the obligatory for stable anaerobic
digestion. Application of mathematical models might be helpful in development of reliable procedures
during the process start-up period. Yet, the accuracy of forecast depends on the quality of input and
parameters. In this study, the specific anaerobic activity (SAA) tests were applied in order to estimate
microbial community structure. Obtained data was applied as input conditions for mathematical model
of anaerobic digestion. The initial values of variables describing the amount of acetate and propionate
utilizing microorganisms could be calculated on the basis of SAA results. The modelling based on those
optimized variables could successfully reproduce the behavior of a real system during the continuous
fermentation.