title: Comparison between discontinuous and continuous lactose conversion processes for the production of prebiotic galacto-oligosaccharides using beta-galactosidase from Lactobacillus reuteri.
abstract: Galacto-oligosaccharide (GOS) formation from lactose in discontinuous and continuous modes of conversion was investigated using beta-galactosidase (beta-gal) from Lactobacillus reuteri. A continuous stirred tank reactor (CSTR) with an external crossflow membrane was set up, and continuous GOS production was analyzed and compared to the batchwise formed GOS product. Marked differences were detected for the two reactor setups. Above 65% lactose conversion, the GOS yield was lower for the CSTR due to a lower content of tri- and tetrasaccharides in the reaction mixture. In the CSTR, beta-gal from L. reuteri showed up to 2-fold higher specificity toward the formation of beta-(1-->6)-linked GOS, with beta-D-Galp-(1-->6)-D-Glc and beta-D-Galp-(1-->6)-D-Gal being the main GOS components formed under these conditions. This could be used to synthesize more defined GOS products.
authors.affiliation: Research Centre Applied Biocatalysis, Petersgasse 14, A-8010 Graz, Austria.
authors.forename: Barbara
authors.initials: B
authors.lastname: Splechtna
authors.forename: Thu-Ha
authors.initials: TH
authors.lastname: Nguyen
authors.forename: Dietmar
authors.initials: D
authors.lastname: Haltrich
mesh_terms: D019149:Bioreactors; D005690:Galactose / Q000378:metabolism*; D052200:Limosilactobacillus reuteri / Q000201:enzymology*; D007785:Lactose / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism*; D019936:Probiotics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D009844:Oligosaccharides; D001616:beta-Galactosidase; D007785:Lactose; D005690:Galactose