@misc{10481/56654,
year = {2018},
url = {http://hdl.handle.net/10481/56654},
abstract = {The success of second-generation (2G) ethanol technology
relies on the efficient transformation of hemicellulose
into monosaccharides and, particularly, on
the full conversion of xylans into xylose for over
18% of fermentable sugars. We sought new hemicellulases
using ruminal liquid, after enrichment of
microbes with industrial lignocellulosic substrates
and preparation of metagenomic libraries. Among
150 000 fosmid clones tested, we identified 22
clones with endoxylanase activity and 125 with bxylosidase
activity. These positive clones were
sequenced en masse, and the analysis revealed
open reading frames with a low degree of similarity
with known glycosyl hydrolases families. Among
them, we searched for enzymes that were thermostable
(activity at > 50°C) and that operate at high
rate at pH around 5. Upon a wide series of assays,
the clones exhibiting the highest endoxylanase and b-xylosidase activities were identified. The fosmids
were sequenced, and the corresponding genes
cloned, expressed and proteins purified. We found
that the activity of the most active b-xylosidase was
at least 10-fold higher than that in commercial enzymatic
fungal cocktails. Endoxylanase activity was in
the range of fungal enzymes. Fungal enzymatic
cocktails supplemented with the bacterial hemicellulases
exhibited enhanced release of sugars from pretreated
sugar cane straw, a relevant agricultural
residue.},
publisher = {John Wiley & Sons Ltd},
title = {Ruminal metagenomic libraries as a source of relevant hemicellulolytic enzymes for biofuel production},
author = {Duque, Estrella and Daddaoua, Abdelali and Cordero, Baldo F. and Udaondo Domínguez, Zulema and Molina Santiago, Carlos Alberto and Roca, Amalia and Solano, Jennifer and Molina Alcaide, Eduarda and Segura, Ana and Ramos, Juan-Luis},
}