title: Excessive excretion of cyclic beta-(1,2)-glucan by Rhizobium trifolii TA-1.
abstract: At 25 degrees C, the optimal temperature for growth of Rhizobium trifolii TA-1, extracellular and capsular polysaccharide (EPS and CPS) were the main carbohydrate products synthesized in mannitol-rich medium (10 g of mannitol and 1 g of glutamic acid per liter). In the same medium at 33 degrees C, EPS and CPS production was inhibited, and up to 3.9 g of cyclic beta-(1,2)-glucan was produced during an incubation period of 20 days with a total biomass of 0.55 g of protein. In a medium containing 50 g of mannitol and 10 g of glutamic acid per liter, high cell densities (3.95 g of protein) were obtained at 25 degrees C. This biomass excreted 10.9 g of cyclic beta-(1,2)-glucan within 10 days. Concomitantly, 4.8 g of EPS were synthesized, while CPS production was strongly suppressed. The excreted cyclic beta-(1,2)-glucans were neutral and had degrees of polymerization ranging from 17 to 25, with a degree of polymerization of 19 as the major glucan cycle.
authors.affiliation: Department of Microbiology, Agricultural University, Wageningen, The Netherlands.
authors.forename: M W
authors.initials: MW
authors.lastname: Breedveld
authors.forename: L P
authors.initials: LP
authors.lastname: Zevenhuizen
authors.forename: A J
authors.initials: AJ
authors.lastname: Zehnder
mesh_terms: D003470:Culture Media; D005936:Glucans / Q000378:metabolism*; D008353:Mannitol / Q000494:pharmacology; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D012231:Rhizobium / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013696:Temperature; D047071:beta-Glucans
chemical_list: D003470:Culture Media; D005936:Glucans; D011135:Polysaccharides, Bacterial; D047071:beta-Glucans; D008353:Mannitol; C033744:beta-1,2-glucan