## 4 Discussion  
Biopolymers are biodegradable polymers produced by different types of living organisms [29]. Exopolysaccharideaccharides (EPSs) are a fascinating biopolymer group formed by a diverse group of microorganisms. EPSs include homopolysaccharides such as dextran and levan, as well as heteropolysaccharides, including xanthans and gellans [5]. Levan is a homopolymer made up of 8-(2,6)-joined fructose residues, which can be generated by archaea, bacteria, and plants. Microorganisms grow faster than plants and algae, and their production processes are simple to manipulate to enhance yields and productivity. Furthermore, the manufacturing process is not affected by weather or seasons, and it can rely on low-cost wastes or by-products as raw materials [1]. Many bacteria, including _B. subtilis_, _Z. mobilis_, _B. lentus_, and _Microbacterium laceninformans_, produce important metabolic products under both oxic and anoxic environments, such as levan polymer [30]. In this study, levan was produced, extracted, characterized, and partially purified from _Bacillus subtilis_ strain MZ292983.1. The bacterial strain was isolated from soil obtained from Princess Nourah bint Abdulrahman University, Saudi Arabia. Screening of levan was performed on sucrose medium, and the addition of sucrose in the media as a substrate induces the bacterial secretion of the levansucircase enzyme [11]. Levasucarse is a fructosyltransferase en enzyme that catalyzes 8-(2,6)-levan formed via the cleavage of sucrose to its fructose and glucose units, as well as fructoligosaccharide formation (FOS) [4]. Furthermore, the morphological results showed a slimy and mucoid appearance, in agreement with [11]. Levasucarse accounts for at least 25% of the released reducing sugars during bacterial growth in the existence of sucrose [31]. In our study, both the amount of total soluble carbohydrates and total reducing sugars were determined and recorded as 90.28 \(\pm\) 1.67 ug mg\({}^{-1}\) and 290 ug mg\({}^{-1}\), respectively. The presence of uronic acids, amino sugars, and sulphate groups can all be determined using FTIR. Nonetheless, infrared spectroscopy is not suitable for structural analysis in detail [32]. Instead, in the field of polysaccharide structural determination, nuclear magnetic resonance (NMR) is the most useful tool. In both \({}^{1}\)H and \({}^{13}\)C spectra,omeric resonances are frequently shown in a distinct region as carbonicic signals, assisting in establishing not just each anomeric configuration's alpha or beta of individual residues but also establishing, with great confidence, the number and relative proportions [2]. Comparison of IR spectra of partially purified levan with previously reported IR data of levan confirmed the similarity of the spectra [32]. Our findings are consistent with previous studies which recommended that carbohydrates showed high absorbance in the fingerprint region of 1200-950 cm\({}^{-1}\). The position and intensity of the bands of each polysaccharide are unique, allowing it to be identified. Spectroscopy of \({}^{1}\)H and \({}^{13}\)C NMR was also widely used in the characterization of levan polymers since it provides distinct and expected characteristics for each constituent, particularly in tiny compounds [33]. NMR analysis aids in the estimation of structural characteristics and saccharide composition within the mixture, as well as its ratio. It also distinguishes branching and linear levan from a plant and provides comprehensive details on the presence of certain \"functional groups\" in the specimen [34]. The spectrum of the \({}^{1}\)H NMR spectrum of the partially purified levan from _Bacillus subtilis_ strain MZ292983.1 was recorded in D\({}_{2}\)O and showed six peaks in the range of 8 3.48-4.11 ppm region, which revealed the existence of sugar protons. The spectrum was identical with previously reported levan polymers [5; 35]. \({}^{1}\)H NMR spectra showed the (2\(\rightarrow\)6) fructofuranoside units of fruct [36].