A total of 74 (3.80%) metabolites are not produced by any reaction of the model: apoACP_c, ag_c, trnaala_c, __iECx55__alpp_p, ap5a_c, ...

Orphans are metabolites that are only consumed but not produced by reactions in the model. They may indicate the presence of network and knowledge gaps. Implementation: Find orphan metabolites structurally by considering only reaction equations and bounds. FBA is not carried out.

There are a total of 33 metabolites (1.70%) without a formula: __iECx55__colipaOA_e, __iECx55__diact_e, __iECx55__indpyr_c, __iECx55__pprdn_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.