Writing in the Journal of Biotechnology, the German researchers state their aim was to combine structure of well-established prebiotics galactooligosaccharides (GOSs) and xylooligosaccharides (XOSs) with fructooligosaccharides (FOSs) to “design a new class of FOSs”.
“With these new substrates we have obtained novel oligosaccharide products that may be of scientific and/or practical interest,” wrote lead author Rafael Beine from the Technical University of Braunschweig.
Beine and co-workers from the Helmholtz Centre for Infection Research and X-Zyme GmbH in Dusseldorf sought to produce novel and potential prebiotics using two forms of the levansucrase enzyme – the wild-type, or the A5 variant.
The prebiotics were synthesised using the levansucrase with various sucrose analogues: beta-d-fructofuranosyl-alpha-d-mannopyranoside (Man-Fru), beta-d-fructofuranosyl-alpha-d-galactopyranoside (Gal-Fru), beta-d-fructofuranosyl-alpha-d-allopyranoside (All-Fru), beta-d-fructofuranosyl-alpha-d-fucopyranoside (d-Fuc-Fru) and beta-d-fructofuranosyl-alpha-d-xylopyranoside (Xyl-Fru). (Sucrose has the systematic name alpha-D-glucopyranosyl-(1↔2)-beta-D-fructofuranoside).
Of the analogues tested, the researcher reported that all except the All-Fru were accepted as substrates for the enzyme.
Having established which sucrose analogues would be accepted by the enzyme, the products were analysed.
Using the A5 variant, which reportedly favours the production of short chain oligosaccharides and not long polymers, and the Xyl-Fru substrate, the researchers report that one main product was produced: a 6-kestose analogue (alpha-Xyl-(1,2)-beta-Fru-(2,6)-beta-Fru).
“As 6-kestose and XOFs have strong prebiotic activity, the impact of this novel product on the probiotic properties should be tested in mammalian gut system,” wrote the researchers.
“However, the efficiency and the transfer-rate of the enzyme need to be improved in future as the high hydrolysis rate may limit the scope of oligosaccharide synthesis,” they concluded.
Adding to a burgeoning market?
The burgeoning prebiotic market has been largely created by three inulin producers, all based in Europe. Other ingredient manufacturers are increasingly looking to promote the prebiotic effect of their products as evidence suggests that prebiotics could be even more useful than the probiotic bacteria that they feed.
Prebiotic ingredients, or those that boost the growth of beneficial probiotic bacteria in the gut, are worth about €90 million in the European marketplace but are forecast to reach €179.7 million by 2010, according to Frost & Sullivan.
The big inulin producers, particularly Beneo-Orafti, have been influential in building the science behind inulin and oligofructose, backing research into potential benefits for a variety of health conditions ranging from bones to colorectal cancer, from immunity to satiety and weight management.
Source: Journal of BiotechnologyPublished online ahead of print 15 August 2008, doi:10.1016/j.jbiotec.2008.07.1998“Synthesis of novel fructooligosaccharides by substrate and enzyme engineering”Authors: R. Beine, R. Moraru, M. Nimtz, S. Na’amnieh, A. Pawlowski, K. Buchholz, J. Seibel