Insights into bacterial cellulose biosynthesis by functional metagenomics on Antarctic soil samples

• Published in: The ISME Journal
• Main Authors: Berlemont, Renaud, Delsaute, Maud, Pipers, Delphine, D'Amico, Salvino, Feller, Georges, Galleni, Moreno, Power, Pablo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2009
• Subjects: Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1038/ismej.2009.48; http://www.nature.com/articles/ismej200948.pdf; http://www.nature.com/articles/ismej200948; https://academic.oup.com/ismej/article-pdf/3/9/1070/56532716/41396_2009_article_bfismej200948.pdf

Abstract In this study, the mining of an Antarctic soil sample by functional metagenomics allowed the isolation of a cold-adapted protein (RBcel1) that hydrolyzes only carboxymethyl cellulose. The new enzyme is related to family 5 of the glycosyl hydrolase (GH5) protein from Pseudomonas stutzeri (Pst_2494) and does not possess a carbohydrate-binding domain. The protein was produced and purified to homogeneity. RBcel1 displayed an endoglucanase activity, producing cellobiose and cellotriose, using carboxymethyl cellulose as a substrate. Moreover, the study of pH and the thermal dependence of the hydrolytic activity shows that RBcel1 was active from pH 6 to pH 9 and remained significantly active when temperature decreased (18% of activity at 10 °C). It is interesting that RBcel1 was able to synthetize non-reticulated cellulose using cellobiose as a substrate. Moreover, by a combination of bioinformatics and enzyme analysis, the physiological relevance of the RBcel1 protein and its mesophilic homologous Pst_2494 protein from P. stutzeri, A1501, was established as the key enzymes involved in the production of cellulose by bacteria. In addition, RBcel1 and Pst_2494 are the two primary enzymes belonging to the GH5 family involved in this process.