3.2.1. GC–MS Analysis for EPSRT7

Gas chromatography (GC–MS) analysis (Figure 3a) exhibited 4 peaks that corresponded to monosaccharides mannose (α-D-mannose and β-D-mannose), glucose (α-D-glucose and β-D-glucose), α-D-galactose, α-D-xylose, with a molar ratio of 1:0.5:0.1:0, respectively. This revealed that the polymer was a heteropolysaccharide with the absence of uronic acids and amino acids. *B. amyloliquefaciens* strains produce a wide variety of different EPS compositions. *B. amyloliquefaciens* strain JN4 [65] produced an EPS that was composed of fructose and glucose with a molar ratio of 46.1:1. *B. amyloliquefaciens* strain C-1 [66] produced two different EPSs: EPS-1 with glucose, mannose, galactose, and arabinose at a 15:4:2:1 ratio, and EPS-2, composed of glucose/mannose at a 3:1 proportion. On the other hand, heteropolysaccharide EPS-K4, isolated from the *B. amyloliquefaciens* DMBA-

K4 strain, contained rhamnose, mannose, glucose, and glucuronic acid at a molar ratio of 23.65:40.09:17.68:11.42 [67].

**Figure 2.** (**a**) The 1H-NMR spectra of Tween 80 initially and after 72 h of biodegradation. (**b**) The elution curve of EPSRT7 by Sephadex G-100 gel filtration. (**c**) The standard curve of relative molecular weight (Mw).

**Figure 3.** Characterisation analysis of EPSRT7. (**a**) GC–MS; (**b**) ATR–FTIR spectra; (**c**) thermogravimetric analysis (TGA); (**d**) differential scanning calorimetry (DSC).
