News and Trends
Sweden's Prime Minister, Stefan Löfven, has unveiled proposals to go carbon-neutral by 2045. The plan is scheduled to start by 1 January, 2018.
The Climate Act would see the nation cut emissions by at least 85% from 1990 levels and offset the remaining 15% by investing in green projects overseas. Under the proposed Climate Act, the government will also be required to include a climate report in the country's annual budget and to produce a climate action plan every four years at the beginning of each new parliamentary term.
Sweden is already on target to generate all of its electricity from renewables by 2040. Last year, the country secured 57% of its power from renewables, including wind and hydro, instead of fossil fuels that contribute to emissions.
Coffee chain Caffè Nero has announced its plans to recycle coffee grounds from its London stores to make coffee logs, which can be used in boilers and woodburners.
The scheme sees recycling specialists First Mile pick up coffee waste from Caffè Nero stores and take it directly to Bio-bean's Cambridgeshire factory to be turned into coffee logs. The company can also turn the waste coffee into biomass pellets. By July 2017, Caffè Nero approximates it will have recycled 218 tons of used coffee grounds into 98 tons of biomass pellets, producing enough fuel to heat 435 homes for a year.
The coffee giant said its partnership with First Mile allows the waste to be transported directly to Bio-bean, rather than via an intermediary depot, helping to avoid 125,000 road miles during the first year of the scheme.
Aside from production of coffee logs and biomass pellets, Bio-bean is also working on a system to turn the oils from coffee waste in to biodiesel. One ton of coffee waste could produce enough renewable fuel to fill four cars.
Research and Development
While commercial cellulase enzymes used in industrial scale cellulosic ethanol plants has greatly improved over the past decade, they are still costly. The team of Simo Ellilä of Brasil Ltda aimed to develop a simple, cost-efficient cellulase production process that could be used locally at a Brazilian sugarcane refinery.
The team evaluated several low-cost industrial residues for cellulase production and found that soybean hulls had the most desirable characteristics. The team then engineered a Trichoderma reesei strain to secrete cellulase in the presence of repressing sugars, which enables it to use sugarcane molasses as a carbon source.
The team also added a heterologous β-glucosidase to improve the performance of the enzymes. Finally, an invertase gene from Aspegillus niger was also added into their strain to allow it to consume sucrose from sugarcane molasses directly. Cost analysis showed that the process provides a low-cost enzyme with good performance on pretreated sugarcane straw.
This study presents the possibility of producing well-performing cellulase at very low costs in Brazil using T. reesei. This system could provide an alternative to commercial cellulases.
Engineers at Massachusetts Institute of Technology have genetically edited a strain of yeast to enable it to convert sugars to fats more efficiently. This could advance the renewable production of high-energy fuels.
Renewable fuels made from corn are useful as gasoline additives for running cars. However, large vehicles need more powerful fuels such as diesel. While some have developed engines that run on biodiesel from used cooking oils, it is relatively scarce and expensive. Sugars from sugar cane and corn are cheaper, but must first be converted into lipids before being transformed.
Researchers, led by Gregory Stephanopoulos, modified the yeast Yarrowia lipolytica to improve its efficiency in ethanol production. They transformed the yeast with synthetic pathways that convert surplus NADH, a product of glucose breakdown, to NADPH, which can be used to synthesize lipids. Using this improved pathway, the yeast cells require only two-thirds of the amount of glucose needed by unmodified yeast cells to produce the same amount of oil.
The researchers believe that there is still room for improve the process. They are also exploring using cheaper sources of plant materials, such as grass and agricultural waste.
Scientists at the Pacific Northwest National Laboratory's Marine Sciences Laboratory, led by Dr. Michael Huesemann, are evaluating algae to find the best biofuel possible. Huesemann started on the algae DISCOVR project (Development of Integrated Screening, Cultivar Optimization and Validation Research) in October 2016 with a small team of senior and junior scientists in Sequim. The project aims to do an organized, rational screening of millions of strains of algae.
The process to find the best algae is broken into a process of five tiers among labs in Sequim, Los Alamos National Laboratory, National Renewable Energy Laboratory, Sandia National Laboratories and Arizona State University's Arizona Center for Algae Technology and Innovation.
In Tier I, scientists will test algae strains to see how weather-tolerant they are, with the top performers going to Tier II. Scientists will then house them using a climate-simulating system called LEAPS (Laboratory Environmental Algae Pond Simulator). They will then evaluate the algae to search for valuable compounds that could make algae biofuel production more cost-effective. Tier I and II are currently being conducted this year.
For Tier III, researchers in New Mexico will further test top-performing algae strains, including forcing them to grow faster or generate more oil using laboratory techniques. Next, strains will be studied in outdoor ponds in Arizona as part of Tier IV to compare biomass output with earlier steps. Lastly, scientists will study the algae strains that performed the best in different lighting and temperature conditions for Tier V.
Once the study is complete, their research will be made public for companies and other researchers.
Energy Crops and Feedstocks for Biofuels Production
Win Phippen of Western Illinois University's Agriculture Department, have recently received a grant through the U.S. Department of Agriculture and the U.S. Department of Energy to advance research on pennycress, which has potential as a biodiesel feedstock.
Pennycress is a winter annual and can be planted in fall, overwinter and be harvested in the spring, with soybean crop planted behind it. However, pennycress' seed shattering is a primary issue. Phippen proposed that pennycress could be improved through gene editing.
Phippen said that pennycress could be light years ahead of corn and soybeans in terms of breeding because it is closely related to Arabidopsis, a model plant for the gene editing technique CRISPR-cas9. Applying CRISPR to pennycress enables optimization of its characters to be more suitable for biodiesel production.
Bamboo is an underutilized biomass source despite being similar to wood. The main challenge for the industrial processing of bamboo is the high level of silica, which negetively affects the process. A scheme for the production of pulp from bamboo needs a process for silica removal as well as to fully utilize all of the materials in the process, including lignin, and cellulosic and hemicellulosic sugars.
Zhaoyang Yuan from the University of British Columbia, United Kingdom, used alkaline pretreatment on bamboo to extract silica before the pulping process. Pretreatment at 95°C with 12% NaOH for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. The silica-free substrate was then used to produce high-grade dissolving pulp. Meanwhile, the dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the liquors from the pretreatment and pulping process were used to produce bio-based chemicals and fuel.
After kraft pulping, xylanase treatment and cold caustic extraction, the team obtained pulp with hemicellulose content of about 3.5%. On the other hand, hydrolysis and fermentation of the liquor showed an ethanol recovery of 0.46 g/g sugar, achieved with 93.2% of hydrolyzed sugars consumed.
This work presents a process that contains alkaline pretreatment, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, allowing bamboo use in industrial processes.
Microalgae are promising sources of renewable biomass for the production of biofuels and valuable chemicals. However, energy-efficient cultivation and harvesting methods are needed to improve its economic viability.
Syracuse University researchers led by Bendy Estime developed a Tris-Acetate-Phosphate-Pluronic (TAPP) medium to efficiently culture and harvest microalgae without affecting the productivity of microalgae. TAPP was designed to undergo a thermoreversible sol-gel transition.
After seeding microalgae in the TAPP medium in a solution phase at 15°C, the temperature is increased by 7°C to induce gelation. Within the gel, microalgae grew in large clusters instead of isolated cells.
The settling velocity of the clusters was approximately ten times larger than that of individual cells cultured in typical solution media. These clusters can easily be harvested by decreasing the temperature to bring the medium to a solution phase.