Figure 3.

Individual line plots of microbial metabolites identified by ¹H-NMR analysis, divided into (A) Organic acids, (B) Amino acids, (C) Sugars, (D) Other compounds, and (E) Other compounds. The plots compare the concentration (mg/L) changes between all experimental time points, after 1, 2, 3, 7, 14, 21, 28, and 35 days of fermentation. Different colors and line shapes indicate different producers: — SK1; - - - SK2. Plots represent the mean metabolite concentration (n = 5 tanks for each producer), and the error bars correspond to the standard deviation. Different superscript letters indicate statistical significance among different time points, within the same producer (p < 0.05) and capital letters indicate a p-value < 0.001. Gray-colored letters refer to SK1, and black underlined letters refer to SK2. No letter indicates no statistical significance after FDR correction.