Carbohydrate esterases involved in deacetylation of food components by the human gut microbiota

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Technical pipeline for screening microbial communities as a function of substrate specificity through fluorescent labelling

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Potential of Wood Hemicelluloses and Their Derivates as Food Ingredients

A holistic utilization of all lignocellulosic wood biomass, instead of the current approach of using only the cellulose fraction, is crucial for the efficient, ecological, and economical use of the forest resources. Use of wood constituents in the food and feed sector is a potential way of promoting the global economy. However, industrially established food products utilizing such components are still scarce, with the exception of cellulose derivatives. Hemicelluloses that include xylans and mannans are major constituents of wood. The wood hemicelluloses are structurally similar to hemicelluloses from crops, which are included in our diet, for example, as a part of dietary fibers. Hence, structurally similar wood hemicelluloses have the potential for similar uses. We review the current status and future potential of wood hemicelluloses as food ingredients. We include an inventory of the extraction routes of wood hemicelluloses, their physicochemical properties, and some of their gastrointestinal characteristics, and we also consider the regulatory route that research findings need to follow to be approved for food solutions, as well as the current status of the wood hemicellulose applications on that route.Peer reviewe

A new generation of versatile chromogenic substrates for high-throughput analysis of biomass-degrading enzymes

BACKGROUND: Enzymes that degrade or modify polysaccharides are widespread in pro- and eukaryotes and have multiple biological roles and biotechnological applications. Recent advances in genome and secretome sequencing, together with associated bioinformatic tools, have enabled large numbers of carbohydrate-acting enzymes to be putatively identified. However, there is a paucity of methods for rapidly screening the biochemical activities of these enzymes, and this is a serious bottleneck in the development of enzyme-reliant bio-refining processes. RESULTS: We have developed a new generation of multi-coloured chromogenic polysaccharide and protein substrates that can be used in cheap, convenient and high-throughput multiplexed assays. In addition, we have produced substrates of biomass materials in which the complexity of plant cell walls is partially maintained. CONCLUSIONS: We show that these substrates can be used to screen the activities of glycosyl hydrolases, lytic polysaccharide monooxygenases and proteases and provide insight into substrate availability within biomass. We envisage that the assays we have developed will be used primarily for first-level screening of large numbers of putative carbohydrate-acting enzymes, and the assays have the potential to be incorporated into fully or semi-automated robotic enzyme screening systems. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13068-015-0250-y) contains supplementary material, which is available to authorized users

The Putative Endoglucanase PcGH61D from Phanerochaete chrysosporium Is a Metal-Dependent Oxidative Enzyme that Cleaves Cellulose

Many fungi growing on plant biomass produce proteins currently classified as glycoside hydrolase family 61 (GH61), some of which are known to act synergistically with cellulases. In this study we show that PcGH61D, the gene product of an open reading frame in the genome of Phanerochaete chrysosporium, is an enzyme that cleaves cellulose using a metal-dependent oxidative mechanism that leads to generation of aldonic acids. The activity of this enzyme and its beneficial effect on the efficiency of classical cellulases are stimulated by the presence of electron donors. Experiments with reduced cellulose confirmed the oxidative nature of the reaction catalyzed by PcGH61D and indicated that the enzyme may be capable of penetrating into the substrate. Considering the abundance of GH61-encoding genes in fungi and genes encoding their functional bacterial homologues currently classified as carbohydrate binding modules family 33 (CBM33), this enzyme activity is likely to turn out as a major determinant of microbial biomass-degrading efficiency

Microwave-assisted production of biodiesel

ncreasing popularity of sour beer urges the development of novel solutions for controlled fermentations both for fast acidification and consistency in product flavor and quality. One possible approach is the use of Saccharomyces cerevisiae in co-fermentation with Lactobacillus species, which produce lactic acid as a major end-product of carbohydrate catabolism. The ability of lactobacilli to ferment beer is determined by their capacity to sustain brewing-related stresses, including hop iso-α acids, low pH and ethanol. Here, we evaluated the tolerance of Lactobacillus brevis BSO464 and Lactobacillus buchneri CD034 to beer conditions and different fermentation strategies as well as their use in the brewing process in mixed fermentation with a brewer’s yeast, S. cerevisiae US-05. Results were compared with those obtained with a commercial Lactobacillus plantarum (WildBrewTM Sour Pitch), a strain commonly used for kettle souring. In pure cultures, the three strains showed varying susceptibility to stresses, with L. brevis being the most resistant and L. plantarum displaying the lowest stress tolerance. When in co-fermentation with S. cerevisiae, both L. plantarum and L. brevis were able to generate sour beer in as little as 21 days, and their presence positively influenced the composition of flavor-active compounds. Both sour beers were sensorially different from each other and from a reference beer fermented by S. cerevisiae alone. While the beer produced with L. plantarum had an increased intensity in fruity odor and dried fruit odor, the L. brevis beer had a higher total flavor intensity, acidic taste and astringency. Remarkably, the beer generated with L. brevis was perceived as comparable to a commercial sour beer in multiple sensory attributes. Taken together, this study demonstrates the feasibility of using L. brevis BSO464 and L. plantarum in co-fermentation with S. cerevisiae for controlled sour beer production with shortened production time.publishedVersio

Knowledge of learning disabilities: the relationship with choice, duty of care and non-aversive approaches

The present study examines the relationship between the knowledge of the diagnostic criteria for a learning disability (based on DSM IV criteria), care practices and experience in health care and social care staff. Responses to a questionnaire were analysed in terms of participants emphasis on: recognizing duty of care; enabling choice; non-aversive and aversive strategies. Results indicated that the knowledge of the criteria for a learning disability was limited, with only I6% of the sample correctly identifying all three criteria. There were no significant differences between the two groups in relation to experience or level of knowledge. No clear cut differences were found between the groups in relation to tendency to emphasize a particular management approach, with the strategies adopted appearing to be influenced by vignettes used in this study. Participants tended to give responses that identified both a recognition of their duty of care to clients and the need to enable choice. Limitations of this study are discussed

Ancient origin of fucosylated xyloglucan in charophycean green algae

Mikkelsen et al. demonstrate molecular and cellular evidence of the evolution of xyloglucan (XyG), a structural component of the cell walls of most land plants, in charophyte algae. This study describes the structure of XyG in charophyte algae, including identification of fucosylated XyG, and furthermore identifies orthologs required to produce XyG

Human gut Faecalibacterium prausnitzii deploy a highly efficient conserved system to cross-feed on β-mannan-derived oligosaccharides

ACKNOWLEDGMENTS We are grateful for support from The Research Council of Norway (FRIPRO program to P.B.P.: 250479; BIONÆR program to B.W.: 244259), the European Research Commission Starting Grant Fellowship (awarded to P.B.P.; 336355 MicroDE), and the Scottish Government Rural and Environmental Sciences and Analytical Services (RESAS) (for P.L. and S.H.D.). S.L.L.R. generated constructs and performed recombinant protein production and purification and functional characterizations of the binding protein and GHs. L.J.L., S.L., and L.M. expressed, purified, and performed functional characterization of FpCE2 and FpCE17. Growth experiments on mannans and SCFA quantifications were performed by G.L. ITC was performed by Å.K.R., Z.L., and L.S.M. G.V.P. and S.L.L.R. conducted the human metagenomic analysis. S.L.L.R., P.B.P., and B.W. conceived the study and supervised research. The manuscript was written primarily by S.L.L.R. with contributions from P.B.P., S.H.D., G.L, L.M., S.L., G.V.P., E.C.M., L.S.M., B.W., and L.J.L. Figures were prepared by S.L.L.R. We declare that we have no competing interests. Funding Information: We are grateful for support from The Research Council of Norway (FRIPRO program to P.B.P.: 250479; BIONÆR program to B.W.: 244259), the European Research Commission Starting Grant Fellowship (awarded to P.B.P.; 336355 MicroDE), and the Scottish Government Rural and Environmental Sciences and Analytical Services (RESAS) (for P.L. and S.H.D.).Peer reviewedPublisher PD

Differential bacterial capture and transport preferences facilitate co-growth on dietary xylan in the human gut

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