Kinetic data analysis and mathematical modeling of intra (wild type vs. engineered) and inter species (Saccharomyces cerevisiae vs. Zymomonas mobilis) dependency for bioethanol production from glucose, xylose or their combination

This study investigates intra (wild type vs engineered) and inter (S. cerevisiae vs Z. mobilis) species kinetic parameters relationship for bioethanol production with glucose, xylose or their combination as a carbon source when the same xylose utilization pathway is engineered in these strains. Kinetic constants of wild type and engineered strains of S. cerevisiae were compared. Through the comparison, and due to the introduction of the xylose pathway in the engineered strain (intra species dependency), a set of correction factors were obtained. The correction factors were then used to determine process parameters in silico (e.g., biomass and product rates) of wild type Z. mobilis from experimental kinetic parameters obtained from an engineered Z. mobilis strain presented in the literature (inter species dependency). The estimated process parameters for wild type Z. mobilis were validated using experimental data generated by the authors and showed good correlation. Results showed a relationship between wild type and engineered strains of the same microorganism. For example, the substrate limitation constants in the engineered strain of xylose (K-s,K-xyl, K-p,x(yl), K-x,K-xyl) and of glucose (K-s,K-glu, K-p,K-glu, K-s,K-glu) were nine and three times higher in the engineered strain compared with that of the wild type (K-s,K-glu, K-p,K-glu, K-x,K-glu) respectively. This study suggests that these correction factors are conserved and can be used as a guide to estimate kinetic constant values for species or strains for which they are not available.

Automated summary

This study investigated the relationship between wild type and engineered strains of the same microorganism in terms of kinetic parameters, and proposed a set of correction factors to estimate kinetic constant values for species or strains for which they are not available. The results showed a correlation between wild type and engineered strains, with specific substrate limitation constants being higher in the engineered strains. These correction factors were found to be conserved and could serve as a guide for estimating kinetic constants in other species or strains.