High activity CAZyme cassette for improving biomass degradation in thermophiles

• Published in: Biotechnology for Biofuels
• Main Authors: Brunecky, Roman, Chung, Daehwan, Sarai, Nicholas S., Hengge, Neal, Russell, Jordan F., Young, Jenna, Mittal, Ashutosh, Pason, Patthra, Vander Wall, Todd, Michener, William, Shollenberger, Todd, Westpheling, Janet, Himmel, Michael E., Bomble, Yannick J.
• Language: unknown
• Published: 2023
• Subjects: 09 BIOMASS FUELS; Kamchatka; Siberia
• Online Access: http://www.osti.gov/servlets/purl/1424574; https://www.osti.gov/biblio/1424574; https://doi.org/10.1186/s13068-018-1014-2

Currently, Thermophilic microorganisms and their enzymes offer several advantages for industrial application over their mesophilic counterparts. For example, a hyperthermophilic anaerobe, Caldicellulosiruptor bescii, was recently isolated from hot springs in Kamchatka, Siberia, and shown to have very high cellulolytic activity. Additionally, it is one of a few microorganisms being considered as viable candidates for consolidated bioprocessing applications. Moreover, C. bescii is capable of deconstructing plant biomass without enzymatic or chemical pretreatment. This ability is accomplished by the production and secretion of free, multi-modular and multi-functional enzymes, one of which, CbCel9A/Cel48A also secretion of free, multi-modular and multi-functional enzymes, one of which, CbCel9A/Cel48A also known as CelA, is able to outperform enzymes found in commercial enzyme preparations. Furthermore, the complete C. bescii exoproteome is extremely thermostable and highly active at elevated temperatures, unlike commercial fungal cellulases. Understanding the functional diversity of enzymes in the C. bescii exoproteome and how inter-molecular synergy between them confers C. bescii with its high cellulolytic activity is an important endeavor to enable the production more efficient biomass degrading enzyme formulations and in turn, better cellulolytic industrial microorganisms. We found that the combination of three or four of the most highly expressed enzymes in the C. bescii exoproteome exhibits such synergistic activity. For example, some discrete combinations of these enzymes mimic and even improve upon the activity of the exoproteome, even though some of the enzymes lack significant activity on their own. We have demonstrated that it is possible to replicate the cellulolytic activity of the native C. bescii exoproteome utilizing a minimal gene set, and that these minimal gene sets are more active than the whole exoproteome. In the future, this may lead to more simplified and efficient cellulolytic enzyme ...