Propionate functions as a feeding state-dependent regulatory metabolite to counter proinflammatory signaling linked to nutrient load and obesity.

The authors thank Drs. Antonio Murgia and Ben McNally of the University of Cambridge Biochemistry Department for their contributions to metabolomics and lipidomic data processing. They thank and acknowledge the assistance of the National Heart, Lung, and Blood Institute DNA Sequencing and Genomics Core in performing the RNA library sequencing and the National Heart, Lung, and Blood Institute Flow Cytometry Core for performing the flow cytometry.Peer reviewe

The acid hydrolysis of sugarcane bagasse hemicellulose to produce xylose, arabinose, glucose and other products

Experimental trials of the dilute acid hydrolysis of bagasse hemicellulose to produce xylose, arabinose, glucose, acid-soluble lignin (ASL) and furfural were conducted using a temperature-controlled digester. The reaction conditions varied were; temperature (80–200°C), mass ratio of solid to liquid (1:5–1:20), type of bagasse material (i.e. bagasse or bagacillo), concentration of acid (0.25–8 wt% of liquid), type of acid (hydrochloric or sulphuric) and reaction time (10–2000 min). Kinetic modelling of the global rates of formation of products was performed. The most accurate kinetic model of the global reaction for the decomposition of xylan was a simple series hydrolysis of xylan to xylose followed by xylose decomposition. Similar schemes were used to model the production of arabinose, glucose and furfural from the hemicellulose. The production of ASL was modelled by a first-order decomposition of lignin to ASL followed by a reversible decomposition of ASL. Yields of up to 220 mg xylose/g solid were achieved, i.e. about 80% of the theoretical xylose available from the bagasse. The bagasse particle size was found to negligibly affect the rate of hydrolysis. Hydrochloric acid was found to be less active for the degradation of xylose compared to sulphuric acid

Measured kinetics of the acid-catalysed hydrolysis of sugar cane bagasse to produce xylose

Experimental trials of the water hydrolysis of bagasse to produce xylose, arabinose and glucose were conducted using a temperature-controlled microwave digester. The experimental variables were temperature, ratio of water mass to bagasse mass, type of bagasse material and reaction time. The pH of the liquid and concentration of dissolved xylose, arabinose and glucose were measured at the completion of each trial. Kinetic modelling of the global rates of formation of monosaccharide products was performed using schemes based on earlier researchers’ models of acid hydrolysis using mineral acids. For the most plentiful product, xylose, the most accurate kinetic model of the global reactions was determined to be two parallel pathways for hydrolysis of xylan to xylose followed by a single pathway for xylose decomposition. The calculated activation energies of the reactions were within the range reported by other researchers for the hydrolysis of a range of lignocellulosic materials using mineral acid