The SBML file is valid with the online validator. However, with cobrapy version 0.26.2 I get this error when I try to read the eciML1515.xml file with cobra.io.read_sbml_model:
raise ValueError('Variable names cannot contain whitespace characters. "%s" contains whitespace character "%s".' % (name, char))
This error comes from the reaction with ID R_protein__32__pseudoreaction on line 61811 of the xml file. Changing this ID to e.g. R_protein_pseudoreaction resolves the issue.