## 3 Results  
### Characteristics of EPS  
The FTIR spectroscopy determined the functional groups present on the surface of the EPS [4]. A strong signal at 3378 cm\({}^{-1}\) confirmed the existence of an alcoholic and/or carboxylic OH stretching, and a signal at 2940 cm\({}^{-1}\) was attributed to the CH stretching. The presence of C\(\equiv\)C was proved by the signal at 2149 cm\({}^{-1}\); the conjugated C=O or the H- bonded carboxylic C=O stretching was assigned to the signal at 1637 cm\({}^{-1}\); and the 777 cm\({}^{-1}\) band confirmed the presence of C-X (alkyl halides) stretching vibrations. A zeta potential value of \(-\)27.4 mV was obtained for the extracted EPS sample [4]. Both \({}^{1}\)H NMR and \({}^{13}\)C NMR spectra derived proton signal positions (shielding and deshielding environment) confirmed that the EPS possessed electronegative substituents or groups, unsaturated carbon, CH\({}_{2}\)-chain and carbonyl groups. For \({}^{1}\)H NMR spectrum of the EPS (Figure 1a), the signals obtained from \(\delta\)-1.9 ppm and \(\delta\)-2.3 ppm resembled CH\({}_{2}\) protons. Signals from \(\delta\)-2.0 ppm confirmed the presence of -CH proton attached to vinylic carbon. Signals from \(\delta\)-3.5-3.8 ppm were assigned to the presence of electronegative group deshielding, and signals \(\delta\)-3.9-4.8 ppm confirmed electronegative oxygen coming from the ester functional group. Figure 1b represents the \({}^{13}\)C NMR spectrum of the EPS. Signals \(\delta\)-27.58-32.20 ppm resembled to-CH\({}_{2}\) protonic group. The presence of electronegative group was indicated from signals \(\delta\)-54.78-63.30 ppm. Signals \(\delta\)-75.07-80.20 ppm confirmed the presence of unsaturated carbon atoms. The signal of \(\delta\)-104.13 ppm indicated the presence of unsaturation. The presence of carbonyl group was determined by signal \(\delta\)-175.49 ppm. Characteristic \({}^{1}\)H NMR and \({}^{13}\)C NMR signal positions of the EPS are shown in Table 1. The MS-ESI (Mass Spectrometry-Electrospray Ionization) depicts the mass spectra of EPS (Figure 2), and this study further confirmed the molecular weight of the EPS sample while the mass 392 \(m/z\) positive ion mode confirmed the identity of the EPS sample.  
\begin{table}
\begin{tabular}{c c} \hline
**Signal Positions** & **Functional Groups Present in EPS** \\ \hline \multicolumn{3}{c}{\({}^{1}\)H NMR signal positions} \\ \(\delta\)-1.9 ppm & -CH\({}_{2}\) protons \\ \(\delta\)-2.0 ppm & -CH proton attached to vinylic carbon \\ \(\delta\)-2.3 ppm & -CH\({}_{2}\) protons \\ \(\delta\)-3.5-3.8 ppm & presence of electronegative group deshielding \\ \(\delta\)-3.9-4.8 ppm & peak due to electronegative oxygen comes from ester functional group \\ \hline \multicolumn{3}{c}{\({}^{13}\)C NMR signal positions} \\ \(\delta\)-27.58-32.20 ppm & -CH\({}_{2}\) protonic groups \\ \(\delta\)-54.78-63.30 ppm & presence of electronegative group \\ \(\delta\)-75.07-80.20 ppm & presence of unsaturated carbon atoms \\ \(\delta\)-104.13 ppm & presence of unsaturation \\ \(\delta\)-175.49 ppm & presence of carbonyl group \\ \hline \end{tabular}
\end{table}
Table 1: Characteristic \({}^{1}\)H NMR and \({}^{13}\)C NMR signal positions with corresponding functional groups of the extracellular polymeric substance (EPS) produced by _Bacillus licheniformis_ strain KX657843 isolated from earthworm (_Metaphire posthuma_) gut.