BackgroundLignocellulose from fast growing hardwood species is a preferred source of polysaccharides for advanced biofuels and “green” chemicals. However, the extensive acetylation of hardwood xylan hinders lignocellulose saccharification by obstructing enzymatic xylan hydrolysis and causing inhibitory acetic acid concentrations during microbial sugar fermentation. To optimize lignocellulose for cost-effective saccharification and biofuel production, an acetyl xylan esterase AnAXE1 from Aspergillus niger was introduced into aspen and targeted to cell walls.Results AnAXE1-expressing plants exhibited reduced xylan acetylation and grew normally. Without pretreatment, their lignocellulose yielded over 25% more glucose per unit mass of wood (dry weight) than wild-type plants. Glucose yields were less improved (+7%) after acid pretreatment, which hydrolyses xylan. The results indicate that AnAXE1 expression also reduced the molecular weight of xylan, and xylan–lignin complexes and/or lignin co-extracted with xylan, increased cellulose crystallinity, altered the lignin composition, reducing its syringyl to guaiacyl ratio, and increased lignin solubility in dioxane and hot water. Lignin-associated carbohydrates became enriched in xylose residues, indicating a higher content of xylo-oligosaccharides.ConclusionsThis work revealed several changes in plant cell walls caused by deacetylation of xylan. We propose that deacetylated xylan is partially hydrolyzed in the cell walls, liberating xylo-oligosaccharides and their associated lignin oligomers from the cell wall network. Deacetylating xylan thus not only increases its susceptibility to hydrolytic enzymes during saccharification but also changes the cell wall architecture, increasing the extractability of lignin and xylan and facilitating saccharification.Electronic supplementary materialThe online version of this article (doi:10.1186/s13068-017-0782-4) contains supplementary material, which is available to authorized users.

Bambusa vulgaris, also known as 'Ora Bansh' in Bangladesh is grown throughout the country for housing and scaffolding purposes. As part of our analgesic and antihyperglycemic plants of Bangladesh screening program, it was of interest to evaluate the analgesic and antihyperglycemic potential of aerial parts of the plant. Methanolic extract of aerial parts (MEBV) at doses of 50, 100, 200 and 400 mg per kg significantly reduced the number of writhings in acetic acid-induced pain model Swiss albino mice by 25.9, 29.6, 37.0, and 44.4%, respectively compared to reductions of 40.7 and 51.9%, respectively, obtained with 200 and 400 mg per kg of a standard analgesic drug, aspirin. MEBV, at doses of 100, 200 and 400 mg per kg also significantly lowered blood glucose levels in mice, respectively, by 32.8, 45.8, and 55.3% compared to control mice. A standard antihyperglycemic drug, glibenclamide, when administered at a dose of 10 mg per kg lowered blood glucose level by 50.8%. Taken together, the results indicate that the aerial parts of the plant possess considerable analgesic and antihyperglycemic potential, which can possibly be attributed to the presence of alkaloids and saponins in the extract.