There is a little information on exopolysaccharide production by endophytic fungi. In this investigation endophytic Pestalotiopsis sp. BC55 was used for optimization of exopolysaccharide production. One variable at a time method and response surface methodology were adopted to find out the best culture conditions and medium compositions for maximum exopolysaccharide production. The organism produced maximum exopolysaccharide (4.320 ± 0.022 g/l EPS) in 250 ml Erlenmeyer flask containing 75 ml potato dextrose broth supplemented with (g%/l) glucose, 7.66; urea, 0.29; CaCl2, 0.05 with medium pH 6.93; after 3.76 days of incubation at 24°C. Exopolysaccharide [EPS (EP-I)] produced by this organism have Mw ∼2×10(5)Da with a melting point range of 122-124°C. Structural elucidation of the EPS (PS-I) was carried out after a series of experiments. Result indicated the presence of only (1→3)-linked β-D-glucopyranosyl moiety. The structure of the repeating unit was established as →3)-β-D-Glcp-(1→.

characterization, exopolysaccharide, purification, optimization, endophytic Pestalotiopsis sp. BC55

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDGlcp	103.1	73.1	84.9	69.2	75.5	61.2


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6
	bDGlcp	4.5	3.04	3.63	3.10	3.52	3.80-3.88


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6
	bDGlcp	103.1/4.5	73.1/3.04	84.9/3.63	69.2/3.10	75.5/3.52	61.2/3.80-3.88

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

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

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