Production and structural characterization of the exopolysaccharide of the Antarctic fungus Phoma herbarum CCFEE 5080.
The filamentous fungus Phoma herbarum CCFEE 5080 isolated from continental Antarctica soil was tested for exopolysaccharide (EPS) production. The fungus grew and produced EPS (up to 13.6 g/l) on a variety of carbon sources among which sorbitol was best, particularly at the concentration of 60 g/l. EPS production was maximum when the nitrogen source was NaNO3 (3 g/l) and the incubation temperature was 28 degrees C. The polysaccharide was purified by repeated precipitation in ethanol and gel filtration and characterized as a homopolymer of glucose having a molecular weight of 7.412 x 10(6); structural analysis indicated the presence of beta-1,3 and beta-1,6 linkages only. After repeated freezing and thawing of the fungal biomass in the presence of EPS, the mycelial growth was much higher than that observed after freezing in the absence of EPS and the difference increased with the number of freeze-thaw cycles. It is hypothesized that the adaptation of P. herbarum CCFEE 5080 to the Antarctic soil microclimatic conditions, characterized by low temperature, high thermal fluctuations and repeated freeze-thaw cycles, might be related to the EPS production ability.
Selbmann
Laura
L
Dipartimento di Scienze Ambientali, University of Tuscia, Piazza dell'Università, 01100 Viterbo, Italy.
Onofri
Silvano
S
Fenice
Massimiliano
M
Federici
Federico
F
Petruccioli
Maurizio
M
D000107:Acetylation; D000864:Antarctic Regions; D050260:Carbohydrate Metabolism; D002850:Chromatography, Gel; D002855:Chromatography, Thin Layer; D003451:Cryoprotective Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D005658:Fungi / Q000254:growth & development / Q000378:metabolism*; D006868:Hydrolysis; D008745:Methylation; D008970:Molecular Weight; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D011134:Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D013012:Sorbitol / Q000378:metabolism
D003451:Cryoprotective Agents; D009566:Nitrates; D011134:Polysaccharides; D013012:Sorbitol; C031618:sodium nitrate