Renew­able chem­ic­al ready for bio­fuels scale-up

“With the sug­ar plat­form, you have pos­sib­il­it­ies,” says Jeremy Luter­bach­er, a postdoc­tor­al research­er and the paper’s lead author. ​“You’ve taken few­er forks down the con­ver­sion road, which leaves you with more end des­tin­a­tions, such as cel­lu­losic eth­an­ol and drop-in bio­fuels.” The research team has pub­lished its find­ings in the Jan. 17, 2014 issue of the journ­al Sci­ence, explain­ing how they use gamma valer­o­lac­tone, or GVL, to decon­struct plants and pro­duce sug­ars that can be chem­ic­ally or bio­lo­gic­ally upgraded into bio­fuels. Because GVL is cre­ated from the plant mater­i­al, it’s both renew­able and more afford­able than con­ver­sion meth­ods requir­ing expens­ive chem­ic­als or enzymes. The pro­cess also con­verts 85 to 95 per­cent of the start­ing mater­i­al to sug­ars that can be fed to yeast for fer­ment­a­tion into eth­an­ol, or chem­ic­ally upgraded fur­ans to cre­ate drop-in bio­fuels. To demon­strate the eco­nom­ic viab­il­ity of this advance, Luter­bach­er needed to con­cen­trate the sug­ar, remove the GVL for reuse, and show that yeast could suc­cess­fully gen­er­ate eth­an­ol from the sug­ar stream. ​“Show­ing that remov­ing and recyc­ling GVL can be done eas­ily, with a low-energy sep­ar­a­tion step, is a little more of an achieve­ment,” says Luter­bach­er. ​“By feed­ing the res­ult­ing sug­ar solu­tion to microor­gan­isms, we proved we wer­en’t pro­du­cing some weird chem­ic­al byproducts that would kill the yeast, and that we were tak­ing out enough GVL to make it non­tox­ic. What’s neat is that we can use addit­ives to make the solu­tion sep­ar­ate,” says Luter­bach­er. ​“It becomes like oil and vin­eg­ar.” Their addit­ive of choice: liquid car­bon diox­ide. ​“It’s green, non­tox­ic and can be removed by simple depres­sur­iz­a­tion once you want GVL and solu­tions of sug­ar to mix again. It’s the per­fect addit­ive,” Luter­bach­er says. An ini­tial eco­nom­ic assess­ment of the pro­cess has indic­ated the tech­no­logy could pro­duce eth­an­ol at a cost sav­ings of roughly 10 per­cent when com­pared with cur­rent state-of-the-art tech­no­lo­gies. For the past sev­er­al years, James Dumes­ic, Steen­bock Pro­fess­or and Michel Boudart Pro­fess­or of Chem­ic­al and Bio­lo­gic­al Engin­eer­ing at UW-Madis­on, and his research group have stud­ied the pro­duc­tion of GVL from bio­mass, and in more recent work they explored the use of GVL as a solvent for the con­ver­sion of bio­mass to fur­an chem­ic­als. ​“The know­ledge gained in these pre­vi­ous stud­ies was invalu­able to us in the imple­ment­a­tion of our new approach to con­vert real bio­mass to aqueous solu­tions of sug­ars that are suit­able for bio­lo­gic­al con­ver­sion,” says Dumes­ic. This research has con­trib­uted new know­ledge to the bio­fuels land­scape, res­ul­ted in four pat­ent applic­a­tions, and gained recog­ni­tion for GVL’s com­mer­cial poten­tial. from WARF’s Accel­er­at­or Pro­gram. Under the Accel­er­at­or Pro­gram effort, Dumes­ic will serve as prin­cip­al invest­ig­at­or for an 18-month pro­ject involving con­struc­tion of a high-effi­ciency bio­mass react­or. The react­or will use GVL to pro­duce con­cen­trated streams of high-value sug­ars and intact lignin solids. Car­bo­hydrates and lignin from the react­or will be delivered to sci­entif­ic col­lab­or­at­ors, includ­ing fel­low GLBRC invest­ig­at­ors, who will optim­ize strategies for con­vert­ing the mater­i­als into valu­able chem­ic­als and fuels. For more inform­a­tion on the GVL tech­no­lo­gies, con­tact licensing(at)warf.org. Source: Uni­ver­sity of Wis­con­sin-Madis­on (by Mar­garet Broeren)