title: A Metagenomic Advance for the Cloning and Characterization of a Cellulase from Red Rice Crop Residues.
abstract: Many naturally-occurring cellulolytic microorganisms are not readily cultivable, demanding a culture-independent approach in order to study their cellulolytic genes. Metagenomics involves the isolation of DNA from environmental sources and can be used to identify enzymes with biotechnological potential from uncultured microbes. In this study, a gene encoding an endoglucanase was cloned from red rice crop residues using a metagenomic strategy. The amino acid identity between this gene and its closest published counterparts is lower than 70%. The endoglucanase was named EglaRR01 and was biochemically characterized. This recombinant protein showed activity on carboxymethylcellulose, indicating that EglaRR01 is an endoactive lytic enzyme. The enzymatic activity was optimal at a pH of 6.8 and at a temperature of 30 °C. Ethanol production from this recombinant enzyme was also analyzed on EglaRR01 crop residues, and resulted in conversion of cellulose from red rice into simple sugars which were further fermented by Saccharomyces cerevisiae to produce ethanol after seven days. Ethanol yield in this study was approximately 8 g/L. The gene found herein shows strong potential for use in ethanol production from cellulosic biomass (second generation ethanol).
authors.affiliation: Departament of Biology and Graduate Program in Agricultural Sciences, State University of Para&#237;ba-UEPB, Campina Grande-PB 58429-500, Brazil. chmeneses@gmail.com.
authors.forename: Carlos
authors.initials: C
authors.lastname: Meneses
authors.affiliation: Graduate Program in Agricultural Sciences, State University of Para&#237;ba-UEPB, Campina Grande-PB 58429-500, Brazil. bruna-reggina@hotmail.com.
authors.forename: Bruna
authors.initials: B
authors.lastname: Silva
authors.affiliation: Departament of Biology, State University of Para&#237;ba-UEPB, Campina Grande-PB 58429-500, Brazil. betsydantas@gmail.com.
authors.forename: Betsy
authors.initials: B
authors.lastname: Medeiros
authors.affiliation: Department of Biochemistry and Molecular Biology, Federal University of Paran&#225;-UFPR, Curitiba-PR 81.531-980, Brazil. rvserrato@ufpr.br.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Serrato
authors.affiliation: Indigo Agriculture, Boston, MA 02129, USA. damojomo@gmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Johnston-Monje
mesh_terms: D018533:Biomass; D002480:Cellulase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D002482:Cellulose / Q000378:metabolism*; D003001:Cloning, Molecular; D004789:Enzyme Activation; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D015870:Gene Expression; D023281:Genomics / Q000379:methods; D006863:Hydrogen-Ion Concentration; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D013696:Temperature
chemical_list: D011994:Recombinant Proteins; D000431:Ethanol; D002482:Cellulose; D002480:Cellulase
keywords: endoglucanase; functional metagenomics; plant compost