Study seeks nature’s best biocata­lysts for bio­fuel production

A team of research­ers from five insti­tu­tions ana­lyzed the abil­ity of six microor­gan­isms to sol­u­bil­ize poten­tial bioen­ergy feed­stocks such as switch­grass that have evolved strong defenses against bio­lo­gic­al and chem­ic­al attack. Sol­u­bil­iz­a­tion pre­pares the plant feed­stocks for sub­sequent fer­ment­a­tion and, ulti­mately, use as fuel. The paper, pub­lished in Bio­tech­no­logy for Bio­fuels, is the most com­pre­hens­ive com­par­at­ive study of its type to date. ​“Start­ing with nature’s best bio­mass-sol­u­bil­iz­ing sys­tems may enable a reduc­tion in the amount of non­bio­lo­gic­al pro­cessing required to pro­duce bio­fuels,” said Oak Ridge Nation­al Labor­at­ory (ORNL) coau­thor Bri­an Dav­is­on. ​“We’re ask­ing the ques­tion – what are nature’s best biocata­lysts?” Their ana­lys­is demon­strated that under care­fully con­trolled con­di­tions, a microbe called Clostridi­um ther­mo­cel­lum is twice as effect­ive as fungal enzymes used by industry today. The research­ers also tested the dif­fer­ent microbes’ per­form­ance with min­im­al pre­treat­ment of the plant mater­i­als, indic­at­ing it may be pos­sible to reduce or elim­in­ate use of heat and chem­ic­als that make the feed­stock access­ible to bio­lo­gic­al pro­cessing. ​“Elim­in­at­ing both enzyme addi­tion and con­ven­tion­al pre­treat­ment is a poten­tial game-changer,” said Dart­mouth engin­eer­ing pro­fess­or Lee Lynd, the study’s cor­res­pond­ing author. The research­ers note that the study was designed to provide indic­a­tions of intrins­ic cap­ab­il­ity and per­form­ance under indus­tri­al con­di­tions. They hope their find­ings will guide the devel­op­ment of advanced pro­cesses to lower costs and improve the effi­ciency of com­mer­cial bio­fuel pro­duc­tion. ​“One of the dir­ec­tions that this study leads is that we might have to go out into nature to find the best bugs, even if they are not the ones we’re most famil­i­ar with,” Lynd said. ​“A major thrust in BESC is that we exclus­ively focus on these non-stand­ard microor­gan­isms that bring strong biocata­lyt­ic abil­it­ies to the table, rather than focus­ing on well-known microor­gan­isms.” The research team also con­sidered the use of mech­an­ic­al dis­rup­tion tech­niques such as milling to com­ple­ment the microor­gan­isms’ bio­lo­gic­al break­down. The study is pub­lished as ​“Bio­lo­gic­al ligno­cel­lu­lose sol­u­bil­iz­a­tion: Com­par­at­ive eval­u­ation of biocata­lysts and enhance­ment via cotreat­ment.” Coau­thors are Dart­mouth College’s Lee Lynd, Julie Paye, Anna Guseva and Sarah Ham­mer; the Nation­al Renew­able Energy Laboratory’s Erica Gjers­ing, Mark Dav­is, Jes­sica Olstad, Bry­on Dono­hoe; ORNL’s Bri­an Dav­is­on; Thanh Yen Nguy­en and Charles Wyman of the Uni­ver­sity of Cali­for­nia, River­side; and Uni­ver­sity of Georgia’s Sivak­u­mar Pat­tath­il and Michael Hahn. BESC is a Depart­ment of Energy Bioen­ergy Research Cen­ter sup­por­ted by DOE’s Office of Sci­ence. ORNL is man­aged by UT-Bat­telle for the Depart­ment of Energy’s Office of Sci­ence. DOE’s Office of Sci­ence is the single largest sup­port­er of basic research in the phys­ic­al sci­ences in the United States, and is work­ing to address some of the most press­ing chal­lenges of our time. Source: Sci​en​ceDaily​.com/BESC