title: Epilactose production by 2 cellobiose 2-epimerases in natural milk.
abstract: It was reported recently that cellobiose 2-epimerases (CE) from various aerobic microorganisms convert lactose to epilactose in defined buffer systems. In this study, we showed that CE from 2 mesophilic microorganisms, Flavobacterium johnsoniae and Pedobacter heparinus, were capable of converting lactose to prebiotic epilactose not only in buffer but also in a complex milk system. First, the 2 enzymes were separately cloned, recombinantly expressed in Escherichia coli, and purified by column chromatography. The production of F. johnsoniae CE was carried out in a stirred-tank reactor, indicating that future upscaling is possible. The bioconversions of milk lactose were carried out at an industrially relevant low temperature of 8°C to avoid undesired microbial contaminations or chemical side reactions. Both enzymes were reasonably active at this low temperature, because of their origin from mesophilic organisms. The enzymes showed different operational stabilities over a 24-h time-course. A conversion yield of about 30 to 33% epilactose was achieved with both enzymes. No side products were detected other than epilactose. Therefore, CE may introduce an added value for particular dairy products by in situ production of the prebiotic sugar epilactose.
authors.affiliation: University of Hohenheim, Institute of Food Science and Biotechnology, Department of Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany.
authors.forename: Manuel
authors.initials: M
authors.lastname: Krewinkel
authors.affiliation: University of Hohenheim, Institute of Food Science and Biotechnology, Department of Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Gosch
authors.affiliation: University of Hohenheim, Institute of Food Science and Biotechnology, Department of Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Rentschler
authors.affiliation: University of Hohenheim, Institute of Food Science and Biotechnology, Department of Biotechnology, Garbenstr. 25, 70599 Stuttgart, Germany. Electronic address: Lutz.Fischer@uni-hohenheim.de.
authors.forename: Lutz
authors.initials: L
authors.lastname: Fischer
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry*; D002241:Carbohydrates; D002475:Cellobiose / Q000737:chemistry*; D003001:Cloning, Molecular; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics; D004187:Disaccharides / Q000096:biosynthesis*; D004926:Escherichia coli; D005417:Flavobacterium / Q000201:enzymology; D005516:Food Microbiology; D007785:Lactose / Q000737:chemistry; D008892:Milk / Q000737:chemistry* / Q000201:enzymology; D060485:Pedobacter / Q000201:enzymology; D056692:Prebiotics / Q000032:analysis; D019998:Racemases and Epimerases / Q000737:chemistry*; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D002241:Carbohydrates; D003470:Culture Media; D004269:DNA, Bacterial; D004187:Disaccharides; D056692:Prebiotics; D002475:Cellobiose; C047464:epilactose; D019998:Racemases and Epimerases; D007785:Lactose
keywords: cellobiose 2-epimerase; epilactose; milk; prebiotic