Selection of Psychrotrophic Leuconostoc spp. from Native Fruits, and Studies on Their Dextransucrases

Abstract

Present study was aimed at selection of psychrotrophic Leuconostoc spp., having dextransucrase activity from native fruits and sauerkraut. Fifty-six colonies of lactic acid bacteria producing dextransucrase were isolated and characterized by physiological-biochemical methods. Seven isolates with high dextransucrase activities (0.68-1.63 IU/mL) were studied in detail including characterization by 16S rDNA sequence comparison. It was found that these isolates grow faster and produced dextransucrase earlier than Leuconostoc mesenteroides B512FMC-13Glc, a mutant form of the commercial strain. Molecular weights of the dextransucrases produced by 7 isolates were determined and acceptor reactions using maltose were studied. Dextranase hydrolysis products of dextrans produced by new enzymes were similar to those of commercially produced B-512 F dextran. The new dextransucrases could find industrial uses and the strains isolated (AN 39-1, Or2p-2, Mu3, and Mu10) could be used as prebiotic producing starters in food fermentations due to having high dextransucrase activity and their growth at 4 degrees C.