Gluco-oligosaccharides synthesized by glucosyltransferases from constitutive mutants of Leuconostoc mesenteroides strain Lm 28.
OBJECTIVE
To find different types of glucosyltransferases (GTFs) produced by Leuconostoc mesenteroides strain Lm 28 and its mutant forms, and to check the effectiveness of gluco-oligosaccharide synthesis using maltose as the acceptor.


RESULTS
Constitutive mutants were obtained after chemical mutagenesis by ethyl methane sulfonate. Lm M281 produced more active GTFs than that obtained by the parental strain cultivated on sucrose. GTF from Lm M286 produced a resistant glucan, based on endo-dextranase and amyloglucosidase hydrolysis. The extracellular enzymes from Lm M286 catalyse acceptor reactions and transfer the glucose unit from sucrose to maltose to produce gluco-oligosaccharides (GOS). By increasing the sucrose/maltose ratio, it was possible to catalyse the synthesis of oligosaccharides of increasing degree of polymerization (DP).


CONCLUSIONS
Different types of GTFs (dextransucrase, alternansucrase and levansucrase) were produced from new constitutive mutants of Leuc. mesenteroides. GTFs from Lm M286 can catalyse the acceptor reaction in the presence of maltose, leading to the synthesis of branched oligosaccharides.


CONCLUSIONS
Conditions were optimized to synthesize GOS by using GTFs from Lm M286, with the aim of producing maximum quantities of branched-chain oligosaccharides with DP 3-5. This would allow the use of the latter as prebiotics.
Iliev
I
I
Department of Biochemistry and Microbiology, Plovdiv University, Plovdiv, Bulgaria.
Vassileva
T
T
Ignatova
C
C
Ivanova
I
I
Haertlé
T
T
Monsan
P
P
Chobert
J-M
JM
D001431:Bacteriological Techniques; D019149:Bioreactors / Q000382:microbiology*; D002851:Chromatography, High Pressure Liquid; D003910:Dextranase / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005020:Ethyl Methanesulfonate; D005964:Glucosyltransferases / Q000378:metabolism*; D016695:Glycosyltransferases / Q000378:metabolism; D007934:Leuconostoc / Q000235:genetics* / Q000378:metabolism*; D008320:Maltose / Q000378:metabolism; D009154:Mutation; D009844:Oligosaccharides / Q000032:analysis / Q000096:biosynthesis*; D019936:Probiotics / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism
D009844:Oligosaccharides; D013395:Sucrose; D008320:Maltose; D005020:Ethyl Methanesulfonate; D016695:Glycosyltransferases; D005964:Glucosyltransferases; C033837:alternansucrase; D003910:Dextranase