In the present study, a cost-effective, robust Microbioreactor based production optimization of levan like exopolysaccharide from marine Bacillus sp. SGD-03 was analysed. FE-SEM analysis has showed the significant fibrillar structure of EPS. Size exclusion chromatography and other analytical data revealed that, produced EPS has a molecular weight of 1.0 × 104 Da and is composed of fructose monosaccharide with hydroxyl, carbonyl, and ether groups. The backbone structure of EPS has a branching pattern of β-(2,6) linkages which confirms the similarity with available levan like polymers. The cost-effective media composition for levan production was demonstrated. The maximum yield of crude levan obtained was 123.9 g/L by response surface methodology using robust BioLector Pro Microbioreactor, and same has been validated with shake flask, 1 L and 10 L pilot-scale fermentation.

structure, EPS, marine, optimization, microbioreactor

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDFruf	59.9	104.2	76.3	75.2	80.3	63.4


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	bDFruf	3.60-3.71	-	4.12	4.03	3.89	3.48-3.83


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	bDFruf	59.9/3.60-3.71		76.3/4.12	75.2/4.03	80.3/3.89	63.4/3.48-3.83

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*OC[C@H]1O[C@](*)(CO)[C@@H](O)[C@@H]1O

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)

Rhizobia produces different types of surface polysaccharides. Among them, cyclic β-(1→2)-D-glucan is located in the periplasmic space of rhizobia and plays an important role in the adaptation of bacteria to osmotic adaptation. Cyclic β-(1→2)-D-glucan (CG), synthesized from Sinorhiozbium meliloti 1021, has a neutral and anionic form. In the present study, we characterized the exact chemical structures of anionic CG after purification using size exclusion s (Bio-Gel P-6 and P-2) chromatography, and DEAE-Sephadex anion exchange chromatography. The exact structure of each isolated anionic CG was characterized using various analytical methods such as nuclear magnetic resonance (NMR), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and matrix associated laser desorption ionization-time of Flight (MALDI-TOF) mass spectrometry. The precise chemical structures of novel anionic CG molecules were elucidated by various NMR spectroscopic analyses, including 1H, 13C, 31P, and 2D HSQC NMR spectroscopy. As a result, we discovered that anionic CG molecules have either glycerophosphoryl or succinyl residues at C6 positions of a neutral CG. In addition, the results of MALDI-TOF mass spectrometric analysis confirmed that there are two types of patterns for anionic CG peaks, where one type of peak was the succinylated CG (SCG) and the other was glycerophospholated CG (GCG). In addition, it was revealed that each anionic CG has one to four substituents of the succinyl group of SCG and glycerophosphoryl group of GCG, respectively. Anionic CG could have potential as a cyclic polysaccharide for drug delivery systems and a chiral separator based on the complexation with basic target molecules.

NMR, characterization, MALDI-TOF, Sinorhizobium meliloti 1021, anionic cyclic beta-(1>2)-D-glucan, cyclic polysaccharide, phosphglycerol substituents

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@H]1[C@H](*)O[C@H](COC(=O)CCC(=O)O)[C@@H](O)[C@@H]1O

262.214 g/mol (C₁₀H₁₄R₂O₈, R = next and previous repeats, not counted in mol weight)