News and Trends
Praj Industries, an engineering company based in India, recently launched a 'Green Fund', focused on helping the company absorb projects on second-generation ethanol plants. This will help the Indian government achieve its target of having 10% ethanol in their fuel by 2022.
With this move, Praj will be the first technology provider to offer 'biomass to ethanol' projects under the Build, Operate & Maintain (BOM) package. The company will provide the technology, build the plant and assist in operating it.
Praj also designed a biomass supply chain model centered on farmers. The model will be helping the farming community generate profit from waste, which will be used to produce ethanol. This will generate rural employment & entrepreneurship opportunities for the youth as well.
Singapore's National Environment Agency (NEA) has formed a partnership with the Nanyang Technological University (NTU Singapore) to develop a $30 million waste-to-energy research facility. The collaboration agreement was signed by Ronnie Tay, CEO of NEA, and Professor Ng Wun Jern, executive director of NTU's Nanyang Environment & Water Research Institute (NEWRI).
The facility will be the first of its kind in Singapore and is planned to enable the translation of emerging waste-to-energy technologies, including the use of syngas. Other projects to be studied at the facility include turning waste and biomass into synthetic gas, cleaning and upgrading syngas to run a gas engine or turbine and using a gas separation membrane to extract oxygen from air.
"NTU has an established track record of industry collaboration and for translating research into impactful commercial applications," commented Prof. Freddy Boey. "It will provide local institutions and industries access to the world-class research facilities and expertise at NTU, helping them to innovate and develop clean solutions that are globally competitive," the professor continued.
Expected to be operational by 2018, the facility will be an open platform to support research as well as personnel training to build technical competencies in waste to energy.
Research and Development
Branched-chain fatty acids (BCFAs) are key precursors of branched-chain fuels, which are superior to straight chain fuels. BCFA production in Gram-negative bacterial hosts is challenging since it competes directly with an efficient straight-chain fatty acid (SCFA) pathway.
The team of Gayle J. Bentley from Washington University recently identified and fixed the bottleneck in BCFA production. The team engineered two protein lipoylation pathways that increased BCFA production dramatically. An Escherichia coli strain expressing an optimized lipoylation pathway produced 276 mg/L BCFA, comprising 85% of the total free fatty acids (FFAs). When the lypolation pathways were partnered with an engineered branched-chain amino acid pathway, BCFA was produced from glucose at 181 mg/L and 72% of total FFA.
This study proves a platform for high percentage BCFA production, and will serve as a basis for production of branched-chain hydrocarbons in engineered bacteria.
Compared with the enzyme systems of fungi, bacteria have evolved distinct systems to degrade lignocellulose. However, bacterial saccharification approaches are not efficient enough without help from β-glucosidases. Hence, to enhance the feasibility of using lignocellulosic biomass for biofuel production, it will be important to develop a novel bacterial saccharification system that does not require β-glucosidases.
Tao Sheng from the Harbin Institute of Technology in China together with a team of researchers isolated a thermophilic bacterium, Ruminiclostridium thermocellum M3, from horse manure. The bacteria is said to be capable of directly degrading lignocellulosic biomass. Ruminiclostridium thermocellum M3 was able to grow on a variety of carbon polymers. The bacterium also showed potential in degrading natural lignocellulosic biomass without pretreatment. The bacterium was tested on several biomass including poplar sawdust, corn cobs, rice straw, and cornstalks.
Ruminiclostridium thermocellum M3 could be a promising candidate for lignocellulose saccharification and may be a valuable choice for the refinement of bioproducts.
Acetic acid, released during hydrolysis of lignocellulosic feedstocks during bioethanol production, inhibits yeast growth and alcoholic fermentation. Yeast should therefore express a high and constitutive level of acetic acid tolerance. However, strategies for increasing acetic acid tolerance of Saccharomyces cerevisiae, based on prolonged cultivation in acetic acid, selected inducible rather than constitutive tolerance.
Serial microaerobic batch cultivation, with alternating transfers to fresh medium with and without acetic acid, generated S. cerevisiae cultures with constitutive acetic acid tolerance. Five single-cell lines from evolution experiments and a constitutively acetic acid tolerant mutant generated from UV-mutagenesis were selected for further studies.
The mutants showed an increased fraction of growing cells upon a transfer to a medium with acetic acid. From the mutants, researchers identified genes with distinct mutations. Further analysis revealed that mutations in the ASG1, ADH3, SKS1 and GIS4 genes conferred acetic acid tolerance. Effects of the mutations in ASG1, ADH3 and SKS1 on acetic acid tolerance were also found to be additive.
Production and Trade
A new renewable energy research center, called VILLUM Center for the Science of Sustainable Fuels and Chemicals, has been inaugurated in Copenhagen, Denmark.
The new centre, located at the Technical University of Denmark (DTU), will be headed by Professor Ib Chorkendorff who will bring together a team of researchers from distinguished universities, including Stanford University, the University of Copenhagen, and the University of Southern Denmark, to work for the centre. The group will be developing technologies that can replace fossil energy and fuel.
Recently, DTU and the University of Copenhagen have also developed a new class of catalysts for fuel cells. Catalysts are materials that have surfaces that can increase the speed of chemical processes. These catalysts can also convert different forms of sustainable energy into chemical energy that can be stored. With further evaluation and studies from the new research center, this invention could pave the way for hydrogen vehicles.
A biofuels firm from Finland, St1, recently announced that its Norwegian subsidiary, Smart Fuel, will build a bioethanol plant at a former paper mill in Norway. The plant will use local forest industry residues as feedstock.
"This project marks a milestone towards delivering on our vision to be the leading seller and producer of CO2-aware energy in Norway. We are very excited about the opportunity to cooperate with Treklyngen and Viken Skog in producing renewable fuel from renewable forest residue," says Thomas Hansen, director of Renewable Energy in Smart Fuel.
St1 focuses on waste-based, advanced ethanol production. In Finland, the company already has four Ethanolix plants utilizing food industry residues and one Bionolix plant producing ethanol from biowaste collected from grocery retailers and the community.
The planned Cellunolix plant will be built in Honefoss and will be designed to produce 50 million litres of ethanol per year. The plant is scheduled to become operational by 2021.
Production of biofuels from lignocellulosic biomass has a number of associated difficulties. A pretreatment step is usually required to enhance saccharification yield. Researchers have been investigating biological alternatives such as the consolidated bioprocessing (CBP), which converts lignocellulose into the desired products in one step.
University of Nottingham researchers, led by Stuart Wilkinson, have recently tested the production of bioethanol from brewers spent grains (BSG) using fungal consolidated bioprocessing (CBP). A fungal CBP system includes a filamentous fungal species, which secretes the enzymes that deconstruct biomass, and a yeast species, which ferments liberated sugars into ethanol.
After evaluating several pairings of fungi, the pair of Aspergillus oryzae and Saccharomyces cerevisiae NCYC479 was found to yield the highest concentrations of ethanol. Further analysis of the selected carbohydrate degrading (CAZy) genes expressed by A. oryzae in the system showed that hemicellulose was deconstructed first, followed by cellulose.
While the CBP approach yields lower ethanol, it requires less energy and water inputs, and will be subject to further investigation and optimization.