title: Structure elucidation of a galactofuranose-rich heteropolysaccharide from aciduric fungus penicillium purpurogenum JS03-21.
abstract: The exopolysaccharide-producing fungus Penicillium purpurogenum JS03-21 from the acidic purple clay was screened to develop greater insights into microbial exopolysaccharide resources from extremophilic microorganisms. An exopolysaccharide JS1-1 was purified from the fermented broth of the aciduric fungus using a combination of ethanol precipitation, anion-exchange and size-exclusion chromatography. JS1-1 was found to be a neutral heteropolysaccharide composed of galactose, mannose and glucose in the ratio of 7.9:2.1:1.0, with a molecular weight of about 26 kDa. JS1-1 was subjected to a series of methylation and partial acid hydrolysis reactions, as well as being analyzed by one- and two-dimensional nuclear magnetic resonance, and the results of these analyses revealed JS1-1 to be a galactofuranose-rich polysaccharide. The main chain of JS1-1 contained two regions, including a galactose part composed of a repeating trisaccharide unit [i.e., →5)-β-D-Galf(1 → 5)-β-D-Galf(1 → 6)-β-D-Galf(1→], and a mannose section consisting of (1 → 6)-linked α-D-Manp residues. Two further segments [i.e., α-D-Glcp(1 → 2)-α-D-Galf (1 → and α-D-Galf(1 → 2)-α-D-Manp(1→] existed as branches that were linked to the O-2 atoms of the (1 → 6)-β-D-Galf and (1 → 6)-α-D-Manp regions of the main chain, respectively. The results of the current study demonstrate that JS1-1 is a unique polysaccharide that is rich in both α and β galactofuranose units and therefore different from most of the other known extracellular polysaccharides. The function of this polysaccharide is currently being researched in our laboratory.
authors.affiliation: College of Food and Pharmacy, Zhejiang Ocean University, 1 South Haida Road, Zhoushan, 316000, People's Republic of China, mojojo1984@163.com.
authors.forename: Yin
authors.initials: Y
authors.lastname: Chen
authors.forename: Wenjun
authors.initials: W
authors.lastname: Mao
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhu
authors.forename: Qingfeng
authors.initials: Q
authors.lastname: Niu
authors.forename: Xubo
authors.initials: X
authors.lastname: Fang
authors.forename: Tao
authors.initials: T
authors.lastname: Li
mesh_terms: D002240:Carbohydrate Sequence; D062610:Fungal Polysaccharides / Q000737:chemistry*; D005690:Galactose / Q000031:analogs & derivatives* / Q000737:chemistry; D008969:Molecular Sequence Data; D010407:Penicillium / Q000737:chemistry*
chemical_list: D062610:Fungal Polysaccharides; D005690:Galactose