Selective Synthesis of Galactooligosaccharides Containing β(1→3) Linkages with β-Galactosidase from (Saphera).

The transglycosylation activity of a novel commercial β-galactosidase from (Saphera) was evaluated. The optimal conditions for the operation of this enzyme, measured with -nitrophenyl-β-d-galactopyranoside, were 40 °C and pH around 6.0.

An efficient continuous flow process for the synthesis of a non-conventional mixture of fructooligosaccharides.

A sustainable and scalable process for the production of a new mixture of fructooligosaccharides (FOS) was developed using a continuous-flow approach based on an immobilized whole cells-packed bed reactor. The technological transfer from a classical batch system to an innovative flow environment allowed a significant improvement of the productivity. Moreover, the stability of this production system was ascertained by up to 7 days of continuous working.

Micro-scale procedure for enzyme immobilization screening and operational stability assays.

Objective: A simple and inexpensive methodology, based on the use of micro-centrifuge filter tubes, is proposed for establishing the best enzyme immobilization conditions.

Results: The immobilized biocatalyst is located inside the filter holder during the whole protocol, thus facilitating the incubations, filtrations and washings. This procedure minimizes the amount of enzyme and solid carrier needed, and allows exploring different immobilization parameters (pH, buffer concentration, enzyme/carrier ratio, incubation time, etc.

Heterologous overproduction of β-fructofuranosidase from yeast Xanthophyllomyces dendrorhous, an enzyme producing prebiotic sugars.

The β-fructofuranosidase Xd-INV from the yeast Xanthophyllomyces dendrorhous is the largest microbial enzyme producing neo-fructooligosaccharides (neo-FOS) known to date. It mainly synthesizes neokestose and neonystose, oligosaccharides with potentially improved prebiotic properties. The Xd-INV gene comprises an open reading frame of 1995 bp, which encodes a 665-amino acid protein.

Galactooligosaccharides formation during enzymatic hydrolysis of lactose: towards a prebiotic-enriched milk.

The formation of galactooligosaccharides (GOS) in skim milk during treatment with several commercial β-galactosidases (Bacillus circulans, Kluyveromyces lactis and Aspergillus oryzae) was analysed in detail, at 4 and 40°C. The maximum GOS concentration was obtained at a lactose conversion of approximately 40-50% with B. circulans and A.

Detailed analysis of galactooligosaccharides synthesis with β-galactosidase from Aspergillus oryzae.

The synthesis of galactooligosaccharides (GOS) catalyzed by β-galactosidase from Aspergillus oryzae (Enzeco) was studied. Using 400 g/L of lactose and 15 U/mL, maximum GOS yield, measured by HPAEC-PAD, was 26.8% w/w of total carbohydrates, obtained at approximately 70% lactose conversion.

Microbial β-glucosidases from cow rumen metagenome enhance the saccharification of lignocellulose in combination with commercial cellulase cocktail.

Background: A complete saccharification of plant polymers is the critical step in the efficient production of bio-alcohols. Beta-glucosidases acting in the degradation of intermediate gluco-oligosaccharides produced by cellulases limit the yield of the final product.

Results: In the present work, we have identified and then successfully cloned, expressed, purified and characterised 4 highly active beta-glucosidases from fibre-adherent microbial community from the cow rumen.

Production of Galacto-oligosaccharides by the β-Galactosidase from Kluyveromyces lactis : comparative analysis of permeabilized cells versus soluble enzyme.

The transgalactosylation activity of Kluyveromyces lactis cells was studied in detail. Cells were permeabilized with ethanol and further lyophilized to facilitate the transit of substrates and products. The resulting biocatalyst was assayed for the synthesis of galacto-oligosaccharides (GOS) and compared with two soluble β-galactosidases from K.

Metagenomic era for biocatalyst identification.

Microbial enzymes have many known applications as biocatalysts. However, only a few of them are currently employed for biocatalysis even though an annotated collection of more than 190 billion bases is available in metagenome sequence databases from uncultured and highly diverse microbial populations. This review aims at providing conceptual and technical bases for the translation of metagenome data into both experimental and computational frameworks that facilitates a comprehensive analysis of the biocatalysts diversity space.

Biochemical characterization of a beta-fructofuranosidase from Rhodotorula dairenensis with transfructosylating activity.

An extracellular beta-fructofuranosidase from the yeast Rhodotorula dairenensis was characterized biochemically. The enzyme molecular mass was estimated to be 680 kDa by analytical gel filtration and 172 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, of which the N-linked carbohydrate accounts for 16% of the total mass. It displays optimum activity at pH 5 and 55-60 degrees C.

Molecular and biochemical characterization of a beta-fructofuranosidase from Xanthophyllomyces dendrorhous.

An extracellular beta-fructofuranosidase from the yeast Xanthophyllomyces dendrorhous was characterized biochemically, molecularly, and phylogenetically. This enzyme is a glycoprotein with an estimated molecular mass of 160 kDa, of which the N-linked carbohydrate accounts for 60% of the total mass. It displays optimum activity at pH 5.

Characterization of a beta-fructofuranosidase from Schwanniomyces occidentalis with transfructosylating activity yielding the prebiotic 6-kestose.

beta-Fructofuranosidases are powerful tools in industrial biotechnology. We have characterized an extracellular beta-fructofuranosidase from the yeast Schwanniomyces occidentalis. The enzyme shows broad substrate specificity, hydrolyzing sucrose, 1-kestose, nystose and raffinose, with different catalytic efficiencies (k(cat)/K(m)).

Biochemical and structural features of a novel cyclodextrinase from cow rumen metagenome.

A novel enzyme, RA.04, belonging to the alpha-amylase family was obtained after expression of metagenomic DNA from rumen fluid (Ferrer et al.: Environ.

Purification and kinetic characterization of a fructosyltransferase from Aspergillus aculeatus.

A fructosyltransferase present in Pectinex Ultra SP-L, a commercial enzyme preparation from Aspergillus aculeatus, was purified to 107-fold and further characterised. The enzyme was a dimeric glycoprotein (20% (w/w) carbohydrate content) with a molecular mass of around 135 kDa for the dimer. Optimal activity/stability was found in the pH range 5.

Beet sugar syrup and molasses as low-cost feedstock for the enzymatic production of fructo-oligosaccharides.

Sugar syrup and molasses from beet processing containing 620 and 570 mg/mL sucrose, respectively, were assayed as low-cost and available substrates for the enzymatic synthesis of fructo-oligosaccharides (FOSs). A commercial pectinase (Pectinex Ultra SP-L, from Aspergillus aculeatus) characterized by the presence of a transfructosylating activity was used as a biocatalyst. The FOS production increased when lowering the initial pH value of syrup (7.