A team of Chinese researchers reported in the journal Bioresource Technology the results of a study that evaluated the feasibility of producing biodiesel from macroalgae under outdoor conditions using urea as nutrient source.

Oil-producing macroalgae have been considered as a promising feedstock for biodiesel production because of their photosynthetic efficiency, high lipid content, and ability to grow in extreme environments. Most experiments on biodiesel production from algae were conducted in the laboratory, with fluorescent lamp as light source. In the present study, Chinese researchers demonstrated the outdoor cultivation of Chlorella sp. (FACHB-1748) under natural sunlight. The macroalgae was isolated from a pond in Huang Gang, China. As nitrogen is required for algal nutrition, the researchers used urea, a low cost and readily available source of nitrogen, to grow the macroalgae under an optimized rate of application.

The researchers found highest algal biomass and lipid productivity with 0.1 g/L urea in large photobioreactors under such outdoor conditions. They also found a significant improvement in lipid content and overall lipid yield with the addition of sodium chloride and acetate. The quality and properties of the biodiesel produced under these conditions were reported to have satisfied the criteria of some international fuel standards based on certain parameters.

Air Canada and Airbus have signed an agreement with the non-profit BioFuelNet Canada to help them find the most sustainable biofuels for aviation and explore the potential of biofuels made from waste feedstocks.

Airbus and Air Canada are part of a broad coalition that has pledged carbon neutral growth from 2020 and to reduce greenhouse emissions by 50 percent by 2050. BioFuelNet, a group hosted by Montreal's McGill University, brings together biofuels researchers in Canada, as well as partners from the industry and the government, in order to accelerate research, development, and commercialisation of advanced biofuels. BioFuelNet Canada focuses its research into non-food biomass based biofuels.

Under the agreement, BioFuelNet will conduct research on diverse raw materials, such as municipal solid waste and agricultural and forestry waste, as well as a range of conversion processes available for biofuel production. The ultimate goal is to determine which advanced biofuels are the most sustainable for aviation.

In Oklahoma, USA, an algae research proposal that will evaluate the biomass and algal oil production potential of microalgae strains native to Oklahoma has been approved with $100,000 in funding.

The approved proposal from Oklahoma State University's Robert M. Kerr Food & Agricultural Products Center (FAPC) ranked No. 1 among 28 plant-related research projects evaluated by the Oklahoma Center for the Advancement of Science & Technology (OCAST).

The OCAST Plant Science Research program aims to promote plant research within Oklahoma. In doing so, the program provides funding to multiple projects each year. This year, the program selected a total of five projects to receive funding, four of which are OSU projects.

The FAPC algae project will screen 18 Oklahoma-native microalgae strains for their potential to grow in wastewater, produce algal biomass, oil and other high-value compounds, in addition to cleaning up wastewater.

In Texas, USA, a collaborative study found a significant increase in ethanol production from a combination of sweet sorghum juice and corn mash.

Sorghum Checkoff announced the results of a benchmark study that was conducted in collaboration with the NCERC at Southern Illinois University Edwardsville. The study evaluated the effects of various amounts of sweet sorghum juice in corn mash on ethanol yield under conditions that are similar to those used in the fuel ethanol industry.

The sweet sorghum juice was used as a replacement for process water. The researchers found that adding sweet sorghum juice to corn mash significantly improves the ethanol yield without requiring additional nutrient or yeast inputs. Results showed that with 50 percent sweet sorghum juice, a 12 percent increase in ethanol yield versus control can be expected without any increase in viscosity, without requiring additional enzymes and without overwhelming the yeast with too much sugar in the system.

The theoretical yield could be as high as 23 percent above the control if all the water were substituted with sorghum juice. This theoretical limit was not tested in the study but it will be the subject of a separate investigation.

The journal Biotechnology for Biofuels reported a 2.6-fold increase in cellulosic ethanol yield with a genetically engineered switchgrass (Panicum virgatum) that produces high levels of a genetic repressor.

Switchgrass has been recognized as a potential lignocellulosic material for biofuel production. Switchgrass, however, is hampered by the so-called recalcitrance problem as a result of the physical and chemical barriers within the biomass, such as lignin and phenolic fermentation inhibitors, that block access to fermentable sugars. Before the sugars can be fermented into biofuels, expensive pretreatment is required to deconstruct the biomass and expose its surfaces for enzymatic breakdown.

To address the problem of recalcitrance in switchgrass, a team of researchers from different US institutions employed a genetic engineering approach specifically by overexpressing the transcription factor referred to as PvMYB4, which represses the phenylpropanoid/lignin biosynthesis pathway genes. Elevated levels of PvMYB4 in genetically modified switchgrass plant significantly reduced the production of lignin and phenolic metabolites that are known fermentation inhibitors, while maintaining the availability of fermentable sugars, as shown by detailed biomass characterization. The strategy was also shown to increase the efficiency of biomass breakdown by up to 300 percent without pretreatment as well as the ethanol yield after 7 days of fermentation by about 2.6-fold compared to control material.

According to the team that published the study, the significant improvement in ethanol yield, proportional to the dramatic reduction of recalcitrance, makes the genetically engineered switchgrass an excellent model for understanding the chemical basis of recalcitrance, and for the development of economically viable lignocellulosic feedstocks for biofuel production.

Researchers at the Agricultural Research Service (ARS) of the US Department of Agriculture have identified a yeast strain that breaks down and ferments the sugars in corn cobs without the addition of costly enzyme.

The new Clavispora strain Y-50464 is a variant that was found to tolerate higher temperatures and presence of cob-derived compounds that interfere with yeast growth and fermentation. Its ability to thrive at higher temperatures would allow its utilization in simultaneous saccharification and fermentation (SSF), a one-step process in cellulosic ethanol production that combines releasing and fermenting sugars.

In an experiment that compared the strain Y-50464 with another strain Y-12632, the USDA-ARS researchers found that with Y-50464, fermentation was faster and ethanol yield was higher without the addition of enzyme beta-glucosidase, one of two enzymes needed for ethanol production from cellulose. The enzymes cellulase and beta-glucosidase are normally added to break down residues and extract sugars from the corn cobs after xylose has been extracted. The researchers found evidence of enzyme activity in Y-50464 extracts, but not in Y-12632 extracts. They later confirmed that Y-50464 contains a new form of beta-glucosidase.

The yeast strain Y-50464 opens an opportunity to eliminate the need for costly additional enzyme for cellulosic ethanol production. The researchers plan to continue exploring options for combining the desirable characteristics of this strain with additional enzymes to further improve bioprocessing for advanced biofuels production.