Identification of a cold-adapted and metal-stimulated β-1,4-glucanase with potential use in the extraction of bioactive compounds from plants

• Published in: International journal of biological macromolecules Vol. 166; pp. 190 - 199
• Main Authors: de Melo, Ricardo Rodrigues, de Lima, Evandro Antonio, Persinoti, Gabriela Felix, Vieira, Plínio Salmazo, de Sousa, Amanda Silva, Zanphorlin, Letícia Maria, de Giuseppe, Priscila Oliveira, Ruller, Roberto, Murakami, Mario Tyago
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.01.2021
• Subjects: Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Biocatalysis; Caffeine - analysis; Caffeine - chemistry; Caffeine extraction; Cobalt - chemistry; Cold Temperature; Cold-adapted enzyme; Endo-β-1,4-glucanase; Enzyme Stability; Glucan 1,4-beta-Glucosidase - chemistry; Glucan 1,4-beta-Glucosidase - metabolism; Guarana seeds; Metal-stimulated activity; Paullinia - chemistry; Seeds - chemistry; Xanthomonas - enzymology; Xanthomonas citri subsp. citri; Cold-adapted enzyme; Guarana seeds; Xanthomonas citri subsp. citri; Metal-stimulated activity; Caffeine extraction; Endo-β-1,4-glucanase
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.10.137

Cold-adapted endo-β-1,4-glucanases hold great potential for industrial processes requiring high activity at mild temperatures such as in food processing and extraction of bioactive compounds from plants. Here, we identified and explored the specificity, mode of action, kinetic behavior, molecular structure and biotechnological application of a novel endo-β-1,4-glucanase (XacCel8) from the phytopathogen Xanthomonas citri subsp. citri. This enzyme belongs to an uncharacterized phylogenetic branch of the glycoside hydrolase family 8 (GH8) and specifically cleaves internal β-1,4-linkages of cellulose and mixed-linkage β-glucans releasing short cello-oligosaccharides ranging from cellobiose to cellohexaose. XacCel8 acts in near-neutral pHs and in a broad temperature range (10–50 °C), which are distinguishing features from conventional thermophilic β-1,4-glucanases. Interestingly, XacCel8 was greatly stimulated by cobalt ions, which conferred higher conformational stability and boosted the enzyme turnover number. The potential application of XacCel8 was demonstrated in the caffeine extraction from guarana seeds, which improved the yield by 2.5 g/kg compared to the traditional hydroethanolic method (HEM), indicating to be an effective additive in this industrial process. Therefore, XacCel8 is a metal-stimulated and cold-adapted endo-β-1,4-glucanase that could be applied in a diverse range of biotechnological processes under mild conditions such as caffeine extraction from guarana seeds. •XacCel8 is a cold-adapted endo-β-1,4-glucanase.•The specificity and mode of action of XacCel8 were characterized.•Cobalt ions conferred higher catalytic activity and stability.•XacCel8 improved caffeine recovery from guarana seeds.