title: Levan-Producing Leuconostoc citreum Strain BD1707 and Its Growth in Tomato Juice Supplemented with Sucrose.
abstract: A levan-producing strain, BD1707, was isolated from Tibetan kefir and identified as Leuconostoc citreum. The effects of carbon sources on the growth of L. citreum BD1707 and levan production in tomato juice were measured. The changes in pH, viable cell count, sugar content, and levan yield in the cultured tomato juice supplemented with 15% (wt/vol) sucrose were also assayed. L. citreum BD1707 could synthesize more than 28 g/liter of levan in the tomato juice-sucrose medium when cultured at 30°C for 96 h. Based on the monosaccharide composition, molecular mass distribution, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra, the levan synthesized by L. citreum BD1707 was composed of a linear backbone consisting of consecutive β-(2→6) linked d-fructofuranosyl units, with an estimated average molecular mass of 4.3 × 10(6) Da.
authors.affiliation: State Key Laboratory of Dairy Biotechnology, Shanghai, China.|Shanghai Engineering Research Center of Dairy Biotechnology, Shanghai, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Han
authors.affiliation: Shanghai Engineering Research Center of Dairy Biotechnology, Shanghai, China.|Dairy Research Institute, Bright Dairy & Food Co., Ltd., Shanghai, China.
authors.forename: Xiaofen
authors.initials: X
authors.lastname: Xu
authors.affiliation: Shanghai Engineering Research Center of Dairy Biotechnology, Shanghai, China.|Dairy Research Institute, Bright Dairy & Food Co., Ltd., Shanghai, China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Dairy Biotechnology, Shanghai, China.|Shanghai Engineering Research Center of Dairy Biotechnology, Shanghai, China.
authors.forename: Zhenmin
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Dairy Biotechnology, Shanghai, China wuzhengjun@brightdairy.com.|Shanghai Engineering Research Center of Dairy Biotechnology, Shanghai, China.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Wu
mesh_terms: D003470:Culture Media / Q000737:chemistry*; D005516:Food Microbiology; D005630:Fructans / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007934:Leuconostoc / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D050296:Microbial Viability; D008970:Molecular Weight; D017550:Spectroscopy, Fourier Transform Infrared; D013395:Sucrose / Q000378:metabolism*; D013696:Temperature; D018609:Tibet; D013997:Time Factors
chemical_list: D003470:Culture Media; D005630:Fructans; D013395:Sucrose; C072599:levan