Selection of psychrotrophic Leuconostoc spp. producing highly active dextransucrase from lactate fermented vegetables.
Leuconostoc is the major bacterial genus in the initial phase of the lactate fermentation of vegetables. The dextransucrase elaborated from this bacterium is used to synthesize dextran polymers or prebiotic oligosaccharides. To use Leuconostoc as a starter culture in the manufacture of the kimchi-like fermented foods at low temperature, we isolated microbial flora that showed fast growth rates and high enzyme activity under the test conditions. Nine hundred colonies of Leuconostoc were collected from kimchi, sauerkraut, and pickled cucumber using three consecutive selection media; after batch culture and enzyme activity assays, four strains were selected. Sequencing of 16S rRNA genes of the strains revealed that HJ-S7 and HJ-S13 were Leuconostoc (Ln.) mesenteroides and HJ-P4 and HJ-P5 were Ln. citreum. When compared to the type strain, Ln. mesenteroides B-512F, HJ-P4 showed a more than twofold faster growth rate and 20-fold higher enzyme activity during cultivation at 8 degrees C. These strains are suitable as oligosaccharide-synthesizing starters for the fermentation of not only kimchi but also sauerkraut and pickled cucumbers.
Eom
Hyun-Ju
HJ
Department of Food Science and Technology, Research Center for Bioresource and Health, Chungbuk National University, Cheongju 361-763, South Korea.
Seo
Dong Mi
DM
Han
Nam Soo
NS
D001937:Brassica / Q000382:microbiology; D005285:Fermentation; D005516:Food Microbiology; D005964:Glucosyltransferases / Q000378:metabolism*; D007700:Kinetics; D007934:Leuconostoc / Q000201:enzymology* / Q000254:growth & development*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014675:Vegetables / Q000382:microbiology*
D012336:RNA, Ribosomal, 16S; D005964:Glucosyltransferases; C020025:dextransucrase