Valorization of cellulose in waste paper into value-added cellobionic acid by genetically engineered Pseudomonas taetrolens

Abstract

To expand the applications of waste paper (WP), we attempted to valorize waste office paper (WOP) into cellobionic acid (CBA) using a two-step biocatalytic method. First, we prepared cellobiose from WOP using commercial cellulases. To increase cellobiose production, we optimized various reaction conditions; the type of cellulases, reaction temperature, the amount of WOP, and the amount of cellulases. Under the optimized reaction conditions, 23 g/L cellobiose was generated from 80 g/L of WOP. CBA was then produced from the prepared cellobiose using recombinant Pseudomonas taetrolens homologously expressing quinoprotein glucose dehydrogenase. From 23 g/L cellobiose derived from WOP, this strain produced 24.1 g/L CBA. We demonstrated for the first time that WOP could be successfully valorized into CBA using cellobiogenic cellulases and a CBA-producing strain. This study sets the groundwork to produce CBA at a low price and is expected to expand the application of CBA in industries.