Fig. 2

K-means clustering of differentially expressed genes (a). GO term enrichment of clustered genes by Fisher’s exact test (b). 866 differentially expressed genes from samples taken at pH 6.48, 6.24, and pH 6.12, compared to samples taken at pH 6.98 were clustered. The % of genes represents the percentage of genes within a cluster that contain the given GO term. Enrichment of GO terms indicates that a significantly higher percentage of genes with GO terms are in clusters (Test Set) than in the C. thermocellum reference genome (α = 0.05)