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A hyperthermophilic and thermostable xylanase of 82 kDa (TtXynA) was purified from the culture supernatant of T. terrestris Co3Bag1, grown on carboxymethyl cellulose (CMC), and characterized biochemically. TtXynA showed optimal xylanolytic activity at pH 5.5 and at 85 °C, and retained more than 90% of its activity at a broad pH range (4.5-10). The enzyme is highly thermostable with a half-life of 23.1 days at 65 °C, and active in the presence of several metal ions. Circular dichroism spectra strongly suggest the enzyme gains secondary structures when temperature increases. TtXynA displayed higher substrate affinity and higher catalytic efficiency towards beechwood xylan than towards birchwood xylan, oat-spelt xylan, and CMC. According to its final hydrolysis products, TtXynA displays endo-/exo-activity, yielded xylobiose, an unknown oligosaccharide containing about five residues of xylose and a small amount of xylose on beechwood xylan. Finally, this report represents the description of the first fungal hyperthermophilic xylanase which is produced by T. terrestris Co3Bag1. Since TtXynA displays relevant biochemical properties, it may be a suitable candidate for biotechnological applications carried out at high temperatures, like the enzymatic pretreatment of plant biomass for the production of bioethanol.

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Food waste is considered a non-valued material and the volume is increasing with population and these wastes can be used as raw materials to produce useful bioproducts. Potato peel waste (PPW), almond shells (AS) and spent coffee grounds (SCG) are such wastes and were used as feedstocks to produce lactic acid (LA) via fermentation. Two lactic acid producing bacterial consortia were screened/selected based on glucose and arabinose fed media and were each used for subsequent fermentations. The food wastes were subjected to either: (i) starch gelatinization, (ii) hydrothermal pretreatment, (ii) hydrothermal and cellulase pretreatment, and (iv) hydrothermal and cellulase pretreatment buffered with CaCO 3 prior to fermentation. The glucose selected consortia was better than the arabinose selected consortia for generating LA, and thus was used for further fermentations trials using pretreated biomass. The best LA yield (0.175 g LA g-1 biomass) was from gelatinized AS than the hydrothermal plus cellulase pretreatment. LA productivity was improved for the hydrothermal plus cellulase pretreated biomass by addition of CaCO 3 as buffer to give LA production rates of 0.063 g LA g-1 PPW, 0.045 g LA g-1 AS and 0.049 g LA g-1 SCG.