A Genome-Scale Metabolic Model of 33047 to Guide Genetic Modifications to Overproduce Nylon Monomers.

Nitrogen fixing-cyanobacteria can significantly improve the economic feasibility of cyanobacterial production processes by eliminating the requirement for reduced nitrogen. sp. ATCC 33047 is a marine, heterocyst forming, nitrogen fixing cyanobacteria with a very short doubling time of 3.8 h. We developed a comprehensive genome-scale metabolic (GSM) model, AnC892, for this organism using annotations and content obtained from multiple databases. AnC892 describes both the vegetative and heterocyst cell types found in the filaments of sp. ATCC 33047. AnC892 includes 953 unique reactions and accounts for the annotation of 892 genes. Comparison of AnC892 reaction content with the GSM of sp. PCC 7120 revealed that there are 109 reactions including uptake hydrogenase, pyruvate decarboxylase, and pyruvate-formate lyase unique to AnC892. AnC892 enabled the analysis of energy production pathways in the heterocyst by allowing the cell specific deactivation of light dependent electron transport chain and glucose-6-phosphate metabolizing pathways. The analysis revealed the importance of light dependent electron transport in generating ATP and NADPH at the required ratio for optimal N fixation. When used alongside the strain design algorithm, OptForce, AnC892 recapitulated several of the experimentally successful genetic intervention strategies that over produced valerolactam and caprolactam precursors.