Kinetic modeling of 1,3-propanediol production from raw glycerol by Shimwellia blattae: Influence of the initial substrate concentration

Abstract

1,3-propanediol (PDO) production from raw glycerol using Shimwellia blattae ATCC 33430 has been studied. Batch cultures of S. blattae under anaerobic conditions have been carried out changing the initial substrate concentration. A kinetic model is proposed to describe the evolution of experimental glycerol, biomass, PDO and by-products concentrations, achieved at different times. The model is able to simulate adequately the experimental data of runs conducted at six different initial raw glycerol concentrations and the parameter values describe the influence of initial substrate concentration on the metabolism of the bacteria. The process was clearly inhibited by initial glycerol concentration from 57.8g/L, affecting the biomass growth, the PDO production and the by-products metabolic flux, that winded up to lactic acid and ethanol synthesis. The best PDO production results were obtained when using around 30g/L of initial glycerol concentration, reaching 13.6g PDO/L, with a yield of 0.49g/g and a productivity of 1.36g/(Lh).