Number of identified proteins of EPS from E. coli MG1655 without and with the starvation for 2 and 7 days (a); the number of upregulated and downregulated proteins in the EPS from E. coli MG1655 under different starvation durations, comparisons were made between 2 days vs. 0 day (b), 7 days vs. 0 day (c), and 7 days vs. 2 days (d) starvation; number of differential proteins assigned to Gene Ontology (GO) terms in comparisons of different groups (e).