Abstract:In order to increase the production of microbial oils and indicate its regular pattern during fermentation process, Saccharomyces cerevisiae As2.516, was used to set up the kinetics models based on the optimal fermentation conditions: the initial addition of hydrolysis liquid of kitchen garbage was 90% (V/V) and the initial pH value of medium was 6, the inoculum was 10% (V/V) at 30 ℃ for 10 d with agitation speed at 180 r/min and aeration rate at 2.5 L/min in a 1L fermentator. Results showed that the S. cerevisiae As 2.516 biomass accumulation presented an S-shaped curve during fermentation, the production of microbial oil displayed a closed correlation with the bacteria biomass. The batch fermentation kinetic models were established (cell growth kinetic model, substrate depletion kinetic model, production formation kinetic model) based on Logistic equations, Luedeking-Piret equations and mass balance calculation. Cell growth kinetic model was , substrate depletion kinetic model was, and production formation kinetic model was, The experimental results fit the predictive values from these proposed models.The correlation coefficients R2 of the three equations were 0.9979, 0.9957, 0.9565, respectively, which indicated a good correlation between experimental values and models. Therefore, those models could be used to describe the process of cell growth, substrate consumption for production of microbial oils by S cerevisiae As2.516 during batch fermentation. The establishment of batch fermentation kinetic models could lay a foundation for theory and provide practical instruction for the application of production microbial oils.
