Hyperthermophilic Cellulase from an Archaeal Enrichment, Identified and Characterized

Scientists from the University of California Berkeley and the University of Maryland School of Medicine (both in the United States) report the existence of a consortium of "three hyperthermophilic archaea enriched from a continental geothermal source by growth at 90°C on crystalline cellulose". Archaea are a class of organisms recently recognized as a distinct "domain" of life on earth (the other domains include Eukaryotes and Bacteria). Many organisms under Archaea are known to thrive in extreme environments (hyperthermophilic and/or hypersaline environments); these organisms have generated research excitement due to their potential to produce new types of enzymes for innovative or "robust" applications. The researchers also mentioned that this is the first report of Archaea being able to "deconstruct" lignocellulose at near-boiling temperatures (90 degrees Celsius).

This discovery of a hyperthermophilic lignocellulose-deconstructing organism opens new and exciting possibilities for lowering the cost of pretreating lignocellulosic biomass for biofuel-ethanol production. The researchers report that a "robust" cellulase enzyme has been identified from the archaeal enrichment. Cellulases are enzymes which breakdown cellulose in plant biomass into component sugars which can be fermented to ethanol. These enzymes are presently active only at mesophilic temperatures (30 degrees Celsius to 50 degrees Celscius). The newly-identified hyperthermophilic cellulase has been observed to have an optimal activity at 109 °C, a half-life of 5 hours at 100 °C, and resistance against denaturation in strong detergents, high-salt concentrations, and ionic liquids. This hyperthermophilic cellulase can enable the simultaneous pretreatment and (high-temperature) saccharification of lignocellulosic biomass. These two processes which are normally carried out in separate reaction vessels, can now be combined in one reaction tank.

Details of the study are published in the journal, Nature Communications (URL above).