There are a total of 24 metabolites (1.23%) without a formula: __iECx55__colipaOA_e, __iECx55__2dhphaccoa_c, __iECx55__diact_e, __iECx55__indpyr_c, __iECx55__5aptn_c, ...

To be able to ensure that reactions are mass-balanced, all model metabolites ought to be provided with a chemical formula. Since it may be difficult to obtain formulas for certain metabolites this test serves as a mere report. Models can still be stoichiometrically consistent even when chemical formulas are not defined for each metabolite. Implementation: Check if each cobra.Metabolite has a non-empty "formula" attribute. This attribute is set by the parser if there is an fbc:chemicalFormula attribute for the corresponding species in the SBML.

A total of 94 (4.81%) metabolites are not consumed by any reaction of the model: hqn_c, acanth_c, aconm_c, alatrna_c, __iECx55__lpp_p, ...

Dead-ends are metabolites that can only be produced but not consumed by reactions in the model. They may indicate the presence of network and knowledge gaps. Implementation: Find dead-end metabolites structurally by considering only reaction equations and bounds. FBA is not carried out.