Engineers convert glycerin efficiently into ethanol, green chemicals via anaerobic fermentation
With biodiesel production in the EU and the US at an all-time high and a record number of new biodiesel plants under construction, the industry is facing an impending crisis over waste glycerin, the major byproduct of biodiesel production. New findings from Rice University suggest a possible answer in the form of the Escherichia Coli bacterium that anaerobically ferments glycerin into ethanol and valuable green chemicals. The efficiency of the conversion process is such that the researchers estimate operational costs to be 40% lower than first generation corn ethanol production.
The breakthrough fits nicely in the emerging concept of the integrated biorefinery that draws on an optimal cascading strategy in which waste-streams from one production process become feedstock for the creation of high value products based on other conversion processes.
For each tonne of biodiesel produced, around 100 kilograms of glycerin (glycerol) is obtained as a byproduct. The vast amount of glycerin that is now flooding the market has turned it from a valuable co-product into a 'waste' stream. This trend has prompted many researchers to find efficient and cost-effective ways to use the resource. So far they found that it can be turned into new types of biopolymers, bioplastic films, and green specialty chemicals such as propylene glycol. Others found glycerin makes for a suitable cattle and poultry feed or for the production of biogas.
Anaerobic fermentation
While some of these researchers are looking at traditional chemical processing - finding a way to catalyze reactions that break glycerin into other chemicals - others, including the Rice scientists, are focused on biological conversion. In biological conversion, researchers engineer a microorganism that can eat a specific chemical feedstock and excrete something useful. One of those biological conversion techniques is called anaerobic fermentation, and oxygen-free process widely used to produce biogas and some drugs. Anaerobic fermentation is the most economical and widely used process for biological conversion.
In a review article [*abstract] in the June issue of Current Opinion in Biotechnology, Ramon Gonzalez, William Akers Assistant Professor in Chemical and Biomolecular Engineering, points out that very few microorganisms are capable of digesting glycerin in such an oxygen-free environment. But they found a way to make the E. Coli bacterium do the job - efficiently and cost effectively.
Gonzalez says the biodiesel industry's rapid growth has created a glycerin glut. The glut has forced glycerin producers like Dow Chemical and Procter and Gamble to shutter plants, and Gonzalez said some biodiesel producers are already unable to sell glycerin and instead must pay to dispose of it:
biofuels :: energy :: sustainability :: ethanol :: biodiesel :: glycerin :: byproduct :: anaerobic fermentation :: biorefinery :: bioeconomy ::
"We are confident that our findings will enable the use of E. coli to anaerobically produce ethanol and other products from glycerin with higher yields and lower costs than can be obtained using common sugar-based feedstocks like glucose and xylose," Gonzalez concluded.
Biorefineries
The bioconversion technique is yet another example of the potential for integrated biorefineries that draw on an optimal cascading strategy in which waste-streams from different conversion processes become new feedstocks for other products. The implementation of biorefineries is aimed at co-producing as many high value products along with biofuels in a highly integrated way.
The report in Current Opinion in Biotechnology was co-authored by postdoctoral research associate Syed Shams Yazdani. Graduate students Yandi Dharmadi and Abhishek Murarka assisted with the research. Gonzalez's research is funded by the U.S. Department of Agriculture and the National Science Foundation.
Image: Because of its ubiquity, E. coli is frequently studied in microbiology and is the current "workhorse" in molecular biology. Its is widely used in genetic engineering and enzymes extracted from it are used industrial fermentation processes.
References:
Syed Shams Yazdania and Ramon Gonzaleza, "Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry" [*abstract], Current Opinion in Biotechnology, Volume 18, Issue 3, June 2007, Pages 213-219, doi:10.1016/j.copbio.2007.05.002
Eurekalert: Biotech breakthrough could end biodiesel's glycerin glut - June 26, 2007.
Article continues
The breakthrough fits nicely in the emerging concept of the integrated biorefinery that draws on an optimal cascading strategy in which waste-streams from one production process become feedstock for the creation of high value products based on other conversion processes.
For each tonne of biodiesel produced, around 100 kilograms of glycerin (glycerol) is obtained as a byproduct. The vast amount of glycerin that is now flooding the market has turned it from a valuable co-product into a 'waste' stream. This trend has prompted many researchers to find efficient and cost-effective ways to use the resource. So far they found that it can be turned into new types of biopolymers, bioplastic films, and green specialty chemicals such as propylene glycol. Others found glycerin makes for a suitable cattle and poultry feed or for the production of biogas.
Anaerobic fermentation
While some of these researchers are looking at traditional chemical processing - finding a way to catalyze reactions that break glycerin into other chemicals - others, including the Rice scientists, are focused on biological conversion. In biological conversion, researchers engineer a microorganism that can eat a specific chemical feedstock and excrete something useful. One of those biological conversion techniques is called anaerobic fermentation, and oxygen-free process widely used to produce biogas and some drugs. Anaerobic fermentation is the most economical and widely used process for biological conversion.
In a review article [*abstract] in the June issue of Current Opinion in Biotechnology, Ramon Gonzalez, William Akers Assistant Professor in Chemical and Biomolecular Engineering, points out that very few microorganisms are capable of digesting glycerin in such an oxygen-free environment. But they found a way to make the E. Coli bacterium do the job - efficiently and cost effectively.
We identified the metabolic processes and conditions that allow a known strain of E. coli to convert glycerin into ethanol. It's also very efficient. We estimate the operational costs to be about 40 percent less that those of producing ethanol from corn. - Ramon Gonzalez, lead author and William Akers Assistant Professor in Chemical and Biomolecular Engineering, Rice UniversityGlycerin glut
Gonzalez says the biodiesel industry's rapid growth has created a glycerin glut. The glut has forced glycerin producers like Dow Chemical and Procter and Gamble to shutter plants, and Gonzalez said some biodiesel producers are already unable to sell glycerin and instead must pay to dispose of it:
biofuels :: energy :: sustainability :: ethanol :: biodiesel :: glycerin :: byproduct :: anaerobic fermentation :: biorefinery :: bioeconomy ::
One pound of glycerin is produced for every 10 pounds of biodiesel. The biodiesel business has tight margins, and until recently, glycerin was a valuable commodity, one that producers counted on selling to ensure profitability. - Ramon Gonzalez, William Akers Assistant Professor in Chemical and Biomolecular EngineeringThe discovery comes at a time when the chemical processing industry is increasingly finding bioprocessing to be a "greener," and sometimes cheaper, alternative to chemical processing.
"We are confident that our findings will enable the use of E. coli to anaerobically produce ethanol and other products from glycerin with higher yields and lower costs than can be obtained using common sugar-based feedstocks like glucose and xylose," Gonzalez concluded.
Biorefineries
The bioconversion technique is yet another example of the potential for integrated biorefineries that draw on an optimal cascading strategy in which waste-streams from different conversion processes become new feedstocks for other products. The implementation of biorefineries is aimed at co-producing as many high value products along with biofuels in a highly integrated way.
The report in Current Opinion in Biotechnology was co-authored by postdoctoral research associate Syed Shams Yazdani. Graduate students Yandi Dharmadi and Abhishek Murarka assisted with the research. Gonzalez's research is funded by the U.S. Department of Agriculture and the National Science Foundation.
Image: Because of its ubiquity, E. coli is frequently studied in microbiology and is the current "workhorse" in molecular biology. Its is widely used in genetic engineering and enzymes extracted from it are used industrial fermentation processes.
References:
Syed Shams Yazdania and Ramon Gonzaleza, "Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry" [*abstract], Current Opinion in Biotechnology, Volume 18, Issue 3, June 2007, Pages 213-219, doi:10.1016/j.copbio.2007.05.002
Eurekalert: Biotech breakthrough could end biodiesel's glycerin glut - June 26, 2007.
Article continues
Tuesday, June 26, 2007
Cuba to assist Nigeria with ethanol production, agriculture
Despite Fidel Castro's criticism of ethanol made from corn (mainly aimed at the US), Cuba itself is investing heavily in producing the biofuel (earlier post). The island state sees it as a way to revive its once thriving sugarcane sector, and to boost its energy security.
The country has had a long history of growing and researching the crop as well as in studying ways to convert it into energy. But years of neglect and the collapse of the Soviet Union (which bought sugar in exchange for fuel), has brought the sector to a standstill. At its best, Cuba produced a massive 10 million tonnes of sugar per year, in 2006 output was less than 1.6 million tonnes. Biofuels offer a unique opportunity to breathe new life into the industry.
The Cuban government now says it is ready to transfer its sugarcane-based ethanol technology to Nigeria, in a South-South cooperation effort.
Elio Olivia, the Cuban Ambassador to Nigeria, told reporters that his country was not only prepared to share its expertise in the production of varieties of sugarcane, but also in the production of alternative sources of energy with Nigeria. Besides sugarcane ethanol, cassava-to-ethanol technologies would be shared as well.
Nigeria is the world's largest producer of the starch rich crop, and "will benefit from such an exercise at both the federal and state levels," Olivia thinks. The African country used to export cassava for use as animal feed to the EU. But a new policy there, which boosted subsidies for European grain farmers, caused the sector in Nigeria to collapse. Biofuels are seen as a new outlet for the abundant crop - as is stressed in Nigeria's Presidential Cassava Initiative.
Cuba and Nigeria are set to hold a session for the Nigeria-Cuba Joint Economic Commission, a bilateral economic cooperation promoting body attended by officials of both countries to discuss possible areas of partnership. The meeting is to be held in Nigeria's capital Abuja in November [entry ends here].
biomass :: bioenergy :: biofuels :: energy :: sustainability :: ethanol :: sugarcane :: cassava :: Nigeria :: Cuba ::
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posted by Biopact team at 8:22 PM 1 comments links to this post