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Efficient screening methods for glucosyltransferase genes in Lactobacillus strains

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Author: Kralj, S. · Geel van - Schutten, G.H. · Maarel, M.J.E.C. van der · Dijkhuizen, L.
Source:Biocatalysis and Biotransformation, 4-5, 21, 181-187
Identifier: 237207
doi: doi:10.1080/10242420310001618519
Keywords: Nutrition · Food technology · Glucan · Glucansucrase · Glucosyltransferase · Lactobacillus · Polysacch aride · Sucrose · Bacteria · Chemical bonds · Genes · Sugar (sucrose) · Synthesis (chemical) · Screening techniques · Enzymes · glucan · glucosyltransferase · lactic acid · polysaccharide · sucrose · bacterial strain · carbohydrate synthesis · cloning · conference paper · controlled study · enzyme activity · gene identification · genetic variability · glycosidation · Lactobacillus · Lactobacillus fermentum · Lactobacillus reuteri · Lactobacillus sakei · Leuconostoc · nonhuman · nucleotide sequence · polymerase chain reaction · screening test · sequence analysis · Streptococcus · Bacteria (microorganisms) · Lactobacillus · Lactobacillus fermentum · Lactobacillus parabuchneri · Lactobacillus reuteri · Lactobacillus sakei · Leuconostoc · Prokaryota · Streptococcus


Limited information is available about homopolysaccharide synthesis in the genus Lactobacillus. Using efficient screening techniques, extracellular glucosyltransferase (GTF) enzyme activity, resulting in α-glucan synthesis from sucrose, was detected in various lactobacilli. PCR with degenerate primers based on homologous boxes of known glucosyltransferase (gtf) genes of lactic acid bacteria strains allowed cloning of fragments of 10 putative gtf genes from eight different glucan producing Lactobacillus strains (five Lactobacillus reuteri strains, one Lactobacillus fermentum strain, one Lactobacillus sake strain and one Lactobacillus parabuchneri strain). Sequence analysis revealed that these lactobacilli possess a large variation of (putative) gtf genes, similar to what has been observed for Leuconostoc and Streptococcus strains. Homologs of GTFA of Lb. reuteri 121 (synthesizing reuteran, a unique glucan with α(1 → 4) and α-(1 → 6) glycosidic bonds) (Kralj et al., 2002) were found in three of the four other Lb. reuteri strains tested. The other Lactobacillus GTF fragments showed the highest similarity with GTF enzymes of Leuconostoc spp.