BioChem - DOS

Microbial β-glucosidases from cow rumen metagenome enhance the saccharification of lignocellulose in combination with commercial cellulase cocktail

Biotechnology for biofuels

Del Pozo, Mercedes V; Ferná ndez-Arrojo, Lucí a; Gil-Martí nez, Jorge; Montesinos, Alejandro; Chernikova, Tatyana N; Nechitaylo, Taras Y; Waliszek, Agnes; Tortajada, Marta; Rojas, Antonia; Huws, Sharon A; Golyshina, Olga V; Newbold, Charles J; Polaina, Julio; Ferrer, Manuel; Golyshin, Peter N

<P><B>Background</B></P><P>A complete saccharification of plant polymers is the critical step in the efficient production of bio-alcohols. Beta-glucosidases acting in the degradation of intermediate gluco-oligosaccharides produced by cellulases limit the yield of the final product.</P><P><B>Results</B></P><P>In the present work, we have identified and then successfully cloned, expressed, purified and characterised 4 highly active beta-glucosidases from fibre-adherent microbial community from the cow rumen. The enzymes were most active at temperatures 45&#x2013;55°C and pH 4.0-7.0 and exhibited high affinity and activity towards synthetic substrates such as <I>p</I>-nitrophenyl-beta-D-glucopyranoside (<I>p</I>NPbetaG) and <I>p</I>NP-beta-cellobiose, as well as to natural cello-oligosaccharides ranging from cellobiose to cellopentaose. The apparent capability of the most active beta-glucosidase, herein named LAB25g2, was tested for its ability to improve, at low dosage (31.25 units g<SUP>-1</SUP> dry biomass, using <I>p</I>NPbetaG as substrate), the hydrolysis of pre-treated corn stover (dry matter content of 20%; 350 g glucan kg<SUP>-1</SUP> dry biomass) in combination with a beta-glucosidase-deficient commercial <I>Trichoderma reseei</I> cellulase cocktail (5 units g<SUP>-1</SUP> dry biomass in the basis of <I>p</I>NPbetaG). LAB25g2 increased the final hydrolysis yield by a factor of 20% (44.5 ± 1.7% vs. 34.5 ± 1.5% in control conditions) after 96&#x2013;120 h as compared to control reactions in its absence or in the presence of other commercial beta-glucosidase preparations. The high stability (half-life higher than 5 days at 50°C and pH 5.2) and 2&#x2013;38000 fold higher (as compared with reported beta-glucosidases) activity towards cello-oligosaccharides may account for its performance in supplementation assays.</P><P><B>Conclusions</B></P><P>The results suggest that beta-glucosidases from yet uncultured bacteria from animal digestomes may be of a potential interest for biotechnological processes related to the effective bio-ethanol production in combination with low dosage of commercial cellulases.</P>

2012

BioMed Central

cc-by

1754-6834

5

pp.73-73

10.1186/1754-6834-5-73

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART73722857

https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/1754-6834-5-73

Beta-glucosidases; Bio-ethanol; Glycosyl hydrolase; Lignocellulose; Metagenome; Rumen