Great Salt Lake research leads to salt-tolerant enzyme

| July 18, 2011

Ionic liquids lack volatility, making the liquids suitable for hotter and quicker reactions with biomass. According the Joint BioEnergy Institute, ionic liquids may also be more efficient in treating biomass and enhancing the yield of sugars from that biomass than the dilute acids or bases typically used in the pulp and paper industry. But the liquids, which are virtually a liquid form of salt, also decrease the ability of the cellulases to produce sugars after pretreatment because the liquids interfere with the enzymes that treat the polypeptides (the building blocks of proteins). A team of researchers from the Joint Genome Institute and JBEI has taken on a research effort to find enzymes that are tolerable of ionic liquids.

The basis of their research has begun with the genomic sequences of a salt tolerant, or halophilic, organism. A pair of researchers on the team, Eddy Rubin, director of JGI and Blake Simmons, vice president of the JBEI deconstruction division, has taken their search for a halophilic organism to one of the most likely places for an organism situated near salt: The Great Salt Lake in Utah. The salt-tolerant microbe they are researching, Halorhabdus utahensis, is actually from another ancient and well documented organism Archaea. Through the Genomic Encyclopedia of Bacteria and Archaea project, the team has sequenced the organism.

Since partaking in the work, the team has published a study documenting the work. “This is one of the only reports of salt-tolerant cellulases, and the only one that represents a true ‘genome-to-function’ relevant to ionic liquids from a halophilic environment,” Simmons said of their work. The strategy of the team, to sequence the microbe taken from the Great Salt Lake region, is one that Simmons said “enhances the possibility of identifying true obligatory halophilic enzymes.”

In addition to work in sequencing the microbe, the team also paired with a researcher based in Israel, Jerry Eichler from Ben Gurion University of the Negev to clone and express a gene in the initial microbe into another haloarchael microbe, which most importantly helped the team to identify a salt-tolerant enzyme produced in the genetically modified microbe that could not only tolerate ionic liquids, but could also withstand high temperatures. “This project,” Simmons said, “has established a very important link between genomic science and the realization of enzymes that can handle very demanding chemical environments, such as those present in a biorefinery.”

The team plans to continue its work in hopes of developing a full suite of salt-tolerant enzymes for biorefinery-type conditions.