News and Trends

Enerkem Inc. recently announced its agreement with Shanghai Marine Diesel Engine Research Institute (SMDERI) to develop a project and jointly build a waste-to-biofuels facility in China.

The agreement was signed by Dr. Donghan Jin, President of Shanghai Marine Diesel Engine Research Institute, and Mr. Vincent Chornet, President and CEO of Enerkem. This was made in the presence of the Premier of Quebec, Mr. Philippe Couillard, as part of the Quebec's trade mission in China.

 "We are honored to be working with such a distinguished group. Combining SMDERI'S expertise in equipment manufacturing and fuel ethanol distribution with our own strength in the conversion of waste to ethanol will create powerful synergies," said Vincent Chornet.

The Agricultural Research Service's Bioenergy Research Unit in Peoria has been focused on studies involving the feedstock switchgrass.

Chemical engineer Bruce Dien evaluated two different switchgrass varieties harvested at three different points in plant development and then pretreated with diluted ammonia. Chemist Michael Bowman led a separate study that focused on xylan levels at three different stages in switchgrass development to see if xylan structures change as the plant matures.

In another study, molecular biologist Ron Hector determined the microorganisms needed to convert xylose to ethanol. Scientists already know that the enzyme "D-xylose isomerase," or XI, is one of several enzymes required to convert xylose into ethanol. But, to date, it has been difficult to harness XI's conversion potential due to the difficulty of expressing XI in yeast strains.

Policies supporting biodiesel production would win if they were on the ballot in next week's elections, according to a U.S. nationwide survey.

Three out of four voters support a tax incentive for biodiesel while seventy-six percent said they support a national renewable fuel standard (RFS). The survey, conducted by Moore Information Opinion Research, included 1,200 registered voters.

"These numbers reflect overwhelming public support for developing cleaner, alternative fuels so that we're not so dangerously dependent on petroleum," said Anne Steckel, NBB's vice president of federal affairs. "These policies are popular because they are effective. We're gradually reducing our dependence on oil. We're reducing harmful and costly pollution. And we're creating jobs and economic activity at home. Congress and the Obama administration should take cues from the people who elected them and step up to make sure we have strong, stable policies supporting biodiesel production."

Research and Development

Jatropha curcas is a promising feedstock for biodiesel production. However, it is susceptible to the geminivirus Indian cassava mosaic virus (ICMV) which severely limits productivity. Hence, the development of virus-resistant J. curcas is crucial. A team led by Nam-Hai Chua, from Rockefeller University, generated transgenic J. curcas plants that expresses an RNA homolog of the key genes of ICMV strain DNA-A, which silenced the viral genes, conferring ICMV resistance.

The efficacy and heritability of resistance was evaluated after two rounds of inoculation to prove that the progeny of transgenic plants were resistant to an ICMV strain. PCR analysis showed that transgenic lines had virus resistance. These transgenic J. curcas plants may now be used in various breeding programs.

Biodiesel processing from microbial lipids using cheap plant feedstock has gained attention. Endophytic bacteria from oleaginous plants are possibly capable of accumulating lipids. However, few studies have been reported of endophytic bacteria isolation and their lipid production using plant extracts.

Liming Xia from Zhejiang University, and a team of researchers isolated a new endophyte Bacillus subtilis HB1310 from the thin-shelled walnut. This strain effectively accumulated lipids using cotton stalk extract as substrate. Batch fermentation was conducted in a bioreactor with optimum conditions and obtained a maximum lipid productivity of 2.3 g/L, lipid content of 39.8% (w/w), and cell dry weight (CDW) of 5.7 g/L, after 48 h. The fatty acid profile of the produced lipids indicates that this strain may be suitable for biodiesel production.

The results showed that the new endophytic bacterium is capable of producing high amounts of lipid rapidly using cotton stalk extract. It products are also suitable for biodiesel production.

Yarrowia lipolytica, a species of yeast, is capable of converting glucose into lipids. However, it lacks the enzymes to break down cellulose and cannot utilize biomass directly. The potential of Y. lipolytica as a bioprocessing strain was investigated by the team of Hui Wei, Wei Wang and Min Zhang from National Renewable Energy Laboratory in the United States. The team engineered critical cellulases from Trichoderma reesei into Yarrowia for it to function as a consolidated bioprocessing strain.

Yarrowia expressed T. reesei endoglucanase II (EGII) and cellobiohydrolase (CBH) II. However, the cellulase T. reesei CBHI was found incompatible to Yarrowia. This forced them to evaluate alternative CBHI enzymes. Among the enzymes evaluated, the T. reesei-Talaromyces emersonii (Tr-Te) chimeric CBHI showed activity comparable to T. reesei CBHI. It also showed synergism with EGII and CBHII in degrading cellulosic substrates.

This study shows the first case of successful expression of a chimeric CBHI in Y. lipolytica, and proves that Y. lipolytica can be genetically engineered to directly convert lignocellulosic substrates to biofuels.

Biofuels Processing

Microbial lipids from plant biomass are promising for the biodiesel industry. These lipids are made through three steps: pretreatment, saccharification, and lipid production. However, use of biomass extracts as feedstock produces low yields at a high cost. A cost-effective and integrated process is required to advance plant biomass-based microbial lipid technology.

Zongbao K. Zhao, from Dalian National Laboratory for Clean Energy and Dalian Institute of Chemical Physics in China, tested three strategies using the oleaginous yeast Cryptococcus curvatus ATCC 20509 as a lipid producer and alkaline-pretreated corn stover as a feedstock. Of the three strategies, the simultaneous saccharification and enhanced lipid production (SSELP) had the highest lipid yield of 159.4 mg/g pretreated corn stover. Cellulolytic enzymes used in the SSELP were also reusable upon recycling of supernatants.

The SSELP required less cellulolytic enzymes and had a higher lipid yield. The process also facilitated enzyme recycling which would lead to reduced enzyme consumption.

Khanh-Quang Tran from the Norwegian University of Science and Technology (NTNU) has found a way to produce "biocrude" from common kelp (Laminaria saccharina). His results have been published in the journal Algal Research.

"What we are trying to do is to mimic natural processes to produce oil," said Tran, an associate professor in NTNU's Department of Energy and Process Engineering. "However, while petroleum oil is produced naturally on a geologic time scale, we can do it in minutes."

In his technique, the fast hydrothermal liquefaction, kelp and water slurry was heated to 350 degrees C at 585 degrees C per minute in small quartz tube "reactors". The technique gave him a bio-oil yield of 79%.  The high heating rate results in a biocrude that is easier to refine. Tran says his process is relatively simple and does not need catalysts.

He's now looking for industrial partners and additional funding to continue his research.