Valorization of Brewer's spent grain to prebiotic oligosaccharide: Production, xylanase catalyzed hydrolysis, in-vitro evaluation with probiotic strains and in a batch human fecal fermentation model
JOURNAL OF BIOTECHNOLOGY
Authors: Sajib, Mursalin; Falck, Peter; Sardari, Roya R. R.; Mathew, Sindhu; Grey, Carl; Karlsson, Eva Nordberg; Adlercreutz, Patrick
Abstract
Brewer's spent grain (BSG) accounts for around 85% of the solid by-products from beer production. BSG was first extracted to obtain water-soluble arabinoxylan (AX). Using subsequent alkali extraction (0.5 M KOH) it was possible to dissolve additional AX. In total, about 57% of the AX in BSG was extracted with the purity of 45-55%. After comparison of nine xylanases, Pentopan mono BG, a GH11 enzyme, was selected for hydrolysis of the extracts to oligosaccharides with minimal formation of monosaccharides. Growth of Bifidobacterium adolescentis (ATCC 15703) was promoted by the enzymatic hydrolysis to arabinoxylooligosaccharides, while Lactobacillus brevis (DSMZ 1264) utilized only unsubstituted xylooligosaccharides. Furthermore, utilization of the hydrolysates by human gut microbiota was also assessed in a batch human fecal fermentation model. Results revealed that the rates of fermentation of the BSG hydrolysates by human gut microbiota were similar to that of commercial prebiotic fructooligosaccharides, while inulin was fermented at a slower rate. In summary, a sustainable process to valorize BSG to functional food ingredients has been proposed.
Validation of a Novel Methodology to Evaluate Changes in the Flare Geometry of Renovisceral Bridging Stent-Grafts After Fenestrated Endovascular Aneurysm Repair
JOURNAL OF ENDOVASCULAR THERAPY
Authors: Overeem, Simon; Schuurmann, Richte; Schumacher, Michiel; Jolink, Floortje; Ketel, Mirte; Nijendijk, Bob; Slump, Kees; Versluis, Michel; de Vries, Jean-Paul
Abstract
Purpose: To validate a novel method to evaluate changes in the geometry of renovisceral bridging stent-grafts (BSGs) in patients undergoing fenestrated endovascular aneurysm repair (fEVAR). Materials and Methods: Retrospective analysis was conducted of serial computed tomography angiograms (CTAs) of 10 fEVAR patients (31 BSGs) with at least 2 years of CTA follow-up. Centerline reconstructions were made through the fenestrated stent-graft (FSG) and each BSG. Flare geometry was reconstructed based on marker coordinates and a mesh of the aortic lumen. The shortest distance was calculated from the top of the flare circumference to the FSG fabric. The amount of flaring was assessed with the flare to fenestration diameter ratio and BSG compression to diameter ratio (D-ratio). All measurements were performed by 2 observers. Interobserver variability was assessed; results are presented as the intraclass correlation coefficient (ICC) and repeatability coefficient (RC). Results: Excellent interobserver agreement was achieved for BSG diameter and flare to fenestration distance calculations (ICC 0.865 and 0.944; RC 2.2% and 4.5%, respectively). Six patients had BSG-related complications during follow-up: 2 type IIIc endoleaks and 4 BSG occlusions. Five of the 6 BSGs with complications showed a considerable change in the D-ratio compared with the first postoperative CTA. Conclusion: Precise assessment of the geometry of visceral BSGs in fEVAR is feasible with the presented method. Geometrical changes that may precede later complications can be detected, which could aid in localization of the origin, but a larger series of patients is necessary to define its true clinical merit.