‘Tequila’ powered bio­fuels more effi­cient than corn or sugar

The plant bet­ter known for mak­ing tequila requires no irrig­a­tion and pro­duces com­par­able or bet­ter yields of eth­an­ol than sug­ar or corn. Eco­nom­ic ana­lys­is shows a first-gen­er­a­tion crop will need gov­ern­ment sup­port to kick­start an industry, research­ers say. The agave plant used to make tequila could be estab­lished in semi-arid Aus­tralia as an envir­on­ment­ally friendly solu­tion to Australia’s trans­port fuel short­age, a team of research­ers at the Uni­ver­sity of Sydney, Uni­ver­sity of Exeter and Uni­ver­sity of Adelaide has found. The effi­cient, low-water pro­cess could also help pro­duce eth­an­ol for hand san­it­iser, which is in high demand dur­ing the COV­ID-19 pan­dem­ic.

In an art­icle pub­lished this week in the Journ­al of Clean­er Pro­duc­tion, Uni­ver­sity of Sydney agro­nom­ist Asso­ci­ate Pro­fess­or Daniel Tan with inter­na­tion­al and Aus­trali­an col­leagues have ana­lysed the poten­tial to pro­duce bioeth­an­ol (bio­fuel) from the agave plant, a high-sug­ar suc­cu­lent widely grown in Mex­ico to make the alco­hol­ic drink tequila.

The agave plant is now being grown as a bio­fuel source on the Ather­ton Table­lands in Far North Queens­land by MSF Sug­ar, and it prom­ises some sig­ni­fic­ant advant­ages over exist­ing sources of bioeth­an­ol such as sug­ar­cane and corn, Asso­ci­ate Pro­fess­or Tan said.

​“Agave is an envir­on­ment­ally friendly crop that we can grow to pro­duce eth­an­ol-based fuels and health­care products,” said Asso­ci­ate Pro­fess­or Tan from the Sydney Insti­tute of Agri­cul­ture. ​“It can grow in semi-arid areas without irrig­a­tion; and it does not com­pete with food crops or put demands on lim­ited water and fer­til­iser sup­plies. Agave is heat and drought tol­er­ant and can sur­vive Australia’s hot sum­mers.” Asso­ci­ate Pro­fess­or Tan assembled the research team and led its eco­nom­ic ana­lys­is. Lead author Dr Xiaoyu Yan from the Uni­ver­sity of Exeter, who led the life­cycle assess­ment, said: ​“Our ana­lys­is high­lights the pos­sib­il­it­ies for bioeth­an­ol pro­duc­tion from agave grown in semi-arid Aus­tralia, caus­ing min­im­um pres­sure on food pro­duc­tion and water resources. ​“The res­ults sug­gest that bioeth­an­ol derived from agave is super­i­or to that from corn and sug­ar­cane in terms of water con­sump­tion and qual­ity, green­house gas emis­sions, as well as eth­an­ol out­put.” This study used chem­ic­al ana­lyses of agave from a pilot agave farm in Kalamia Estate, Queens­land (near Ayr) under­taken by Dr Kend­all Corb­in for her Uni­ver­sity of Adelaide PhD, super­vised by Pro­fess­or Rachel Bur­ton. ​“It is fab­ulous that the res­ults of my chem­ic­al ana­lys­is can be used in both an eco­nom­ic and envir­on­ment­al foot­print study and have real-world applic­a­tions”, Dr Corb­in said.

Eco­nom­ic analysis

​“The eco­nom­ic ana­lys­is sug­gests that a first gen­er­a­tion of bioeth­an­ol pro­duc­tion from agave is cur­rently not com­mer­cially viable without gov­ern­ment sup­port, giv­en the recent col­lapse in the world oil price,” Asso­ci­ate Pro­fess­or Tan said. ​“How­ever, this may change with the emer­ging demand for new eth­an­ol-based health­care products, such as hand san­it­isers.” ​“This is the first com­pre­hens­ive life­cycle assess­ment and eco­nom­ic ana­lys­is of bioeth­an­ol pro­duced from a five-year agave field exper­i­ment in north Queens­land. Our ana­lys­is shows a bioeth­an­ol yield of 7414 litres a hec­tare each year is achiev­able with five-year-old agave plants.” The study found that sug­ar­cane yields 9900 litres a hec­tare each year. How­ever, agave out­per­forms sug­ar­cane on a range of meas­ures, includ­ing fresh­wa­ter eutroph­ic­a­tion, mar­ine eco­tox­icity and – cru­cially – water con­sump­tion. Agave uses 69 per­cent less water than sug­ar­cane and 46 per­cent less water than corn for the same yield. For US corn eth­an­ol, the yield was lower than agave, at 3800 litres a hec­tare a year. ​“This shows agave is an eco­nom­ic and envir­on­ment­al win­ner for bio­fuel pro­duc­tion in the years to come,” Asso­ci­ate Pro­fess­or Tan said.

Declar­a­tion

The authors acknow­ledge the con­tin­ued sup­port and gen­er­os­ity of Mr Don Cham­bers, Chief Exec­ut­ive of Aus­Agave, in allow­ing access to the Kalamia site in Queens­land and exper­i­ment­al use of the agave mater­i­al. Source: Uni­ver­sity of Sydney, News, 02.04.2020