- The enzymes needed to convert corn starch to glucose fermented to ethanol by yeast can now be found in new corn and ‘superior yeast,’ reducing the total enzyme addition by more than 80 percent.
- Using a vacuum flashing process, removing ethanol from the tank as it is produced insures yeast health and allows complete fermentation of corn solids up to 40 percent.
- Using high solids in the slurry reduces the amount of water needed as well as the amount of energy required to remove the water.
URBANA - New research at the Integrated Bioprocessing Research Laboratory (IBRL) on the University of Illinois Urbana-Champaign campus could significantly change ethanol production by lowering operating costs and simplifying the dry grind process.
“There are currently more than 200 dry grind plants that are processing corn to produce ethanol,” says Vijay Singh, director of IBRL and a professor in agricultural and biological engineering. “The dry grind process requires two different enzymes to convert corn starch to glucose, which is further fermented to ethanol by yeast.”
Singh says that process has been simplified by combined use and optimization of three new technologies. “A new corn developed by transgenic technology, known as amylase corn, produces one of these enzymes in the grain itself, and a newly engineered ‘superior yeast’ provides the second enzyme, as well as fermenting the glucose.
“There is a high expression level of the first enzyme, α-amylase, in the new corn, so only a small amount [15 percent was tested in these studies] of this corn is required to be mixed with conventional dent corn,” Singh notes. “The superior yeast provides the second enzyme, glucoamylase, and also provides an alternate metabolic pathway to reduce by-product formation during fermentation. Combined use of this corn and superior yeast can reduce the total enzyme addition by more than 80 percent.”
Another approach to improve the dry grind process is to use high solids in the plant. However, according to Singh, high solid concentrations leads to high ethanol build-up in the tank. “High ethanol affects the yeast viability and inhibits its fermentation performance, so we have added a third technology to the process. We remove the ethanol as it is being produced, using a vacuum flashing process that is patented technology from the University of Illinois. Only a couple of vacuum cycles of 1 to 1.5 hours can bring the ethanol concentration below the inhibitory levels without affecting yeast health and allow complete fermentation of corn solids up to 40 percent,” says Singh.
Deepak Kumar, a postdoctoral research associate in agricultural and biological engineering, says because the dry grind process uses a significant amount of water, using more solid material in the slurry - 40 percent as opposed to 30-35 percent - means less water going into the process. “When ethanol is produced, it is in a very dilute solution. You have a small amount of ethanol and a large amount of water,” says Kumar. “We cut down the water use by pushing high solids. When we reduce the amount of water, we also reduce the amount of energy required to remove the water.”
Singh believes this new research has the potential to improve the economics and process efficiencies and simplify the dry grind process. “By developing highly optimized technologies, we will benefit the entire dry grind industry,” he concludes.
Singh and Kumar received the 2016 Bioenergy Society of Singapore (BESS) Achievement Award for their work, in particular their paper “Dry-grind Processing using Amylase Corn and Superior Yeast to Reduce the Exogenous Enzyme Requirements in Bioethanol Production.” This award recognizes the importance of research on bio-energy and bio-based chemicals and was given to Singh and Kumar for their contributions to biofuels research. The paper has been published in Biotechnology for Biofuels, and the full text can be found online at http://bit.ly/2f4JFe3.
Grow tillandsias for the holiday season
URBANA, Ill. – Plant enthusiasts should check out tillandsia this holiday season, according to University of Illinois Extension educator Kelly Allsup.
“Even if you describe yourself as a brown thumb and are allergic to soil, you are going to love growing these super easy plants. The strappy tillandsia plants come in different sizes, textures, and colors and you are sure to find one to fit your holiday décor,” Allsup says.
Tillandsia is a type of epiphyte or “air plant.” In the wild, they use their minimal root system to attach themselves to trees and rocks, absorbing moisture and nutrients through small scales on their leaves. These scales give the plants their unique silver or gray appearance. “Air plants resemble a little octopus with their spreading tentacles,” Allsup says.
“They have been made popular as a houseplant and generally are easy to care for,” Allsup notes. “They enjoy indirect sun within the home or a shadier location if placed outside. Watering is critical. We recommend watering tillandsia once per week by submerging the entire plant in a bowl for 30 minutes to 2 hours. Allow them to dry a couple of hours before putting back into an enclosed environment. Misting can be done once or twice a week depending on the season.”
Tillandsia flowers range from white to bold orange, red, purple, or pink. Blossoms can quickly fade away or persist for several months. The flowers are long, tubular to funnel shaped, with showy floral parts. If they do not bloom, this may be an indication of insufficient light.
Allsup explains that there are two main types of tillandsias. “Some are gray and some are green. The gray kinds are native to tropical forests where long droughts are common. Their gray leaves reflect sunlight and conserve moisture. These can be mounted and grown in bright filtered light. Green-leaved tillandsias are native to rainy, humid tropical forests and are grown best in less light inside containers to keep them moist. Our Illinois winter homes are most appropriate for the gray kinds.”
Allsup recommends the following tillandsias for Illinois:
- Tillandsia caput-medusae has silvery twisty leaves, a swollen base, and a red flower stalk.
- Tillandsia plumosa boasts silvery leaves and can be grown on rocks or limbs.
- Tillandsia utriculata v. pringleyi has delicate thin silver leaves with a flowering stalk that is red to orange or pink.
Tillandsias can be displayed in a variety of artistic ways. For example, Allsup recommends creating a unique wreath by using the formed grapevine wreaths found in craft stores as a base. “Glue a variety of tillandsias, either in on one part of the wreath for an asymmetrical effect or throughout and then add small pine cones, colorful mosses, or miniature festive decorations,” she says.
“Or create a tillandsia landscape in a lantern, square glass vase, or under a cloche,” Allsup suggests. “Fill it with moss or aquarium gravel for a base, place in tillandsias, and adorn with pinecones, miniature décor, and driftwood. You could also place them in wine glasses and line them up along the center of the holiday table.
“For a unique gift,” Allsup adds, “place tillandsia in a clear plastic or glass ornament with colorful moss, or glue tillandsia to a wine cork or crystal.”
Will US corn and soybean surpluses be reduced next year?
URBANA, Ill. – The USDA’s November World Agricultural Supply and Demand Estimates (WASDE) report projected that U.S. stocks of corn will grow from 1.738 billion bushels at the beginning of the current marketing year to 2.403 billion bushels at the end of the marketing year. Soybean stocks are expected to grow from 197 million bushels to 480 million bushels.
According to University of Illinois agricultural economist Darrel Good, large increases in stocks are expected even though corn consumption during the current marketing year is expected to exceed that of last year by 948 million bushels (6.9 percent) and soybean consumption is expected to increase by 165 million bushels (4.2 percent).
“Increased corn consumption is projected in both the feed and residual and export categories,” Good says. “A majority of the expected increase in soybean consumption is in the export category. The expected increase in stocks reflects the extremely large crops produced this year.”
Good says the large crops and resulting low prices are creating increased financial stress for corn and soybean producers and a lot of interest in how long surpluses and low prices might persist. “For now, much of the focus is on the potential size of the 2017 South American crops and the implications for demand for U.S. crops,” Good says. “Increasingly, the focus will shift to 2017 production prospects in the United States. The over-riding question is whether surpluses and low prices will persist for another year. It is a bit early to speculate on supply and consumption prospects for the 2017-18 marketing year, but some scenarios can be considered.”
For corn, Good says there is a general expectation that U.S. producers will reduce acreage in the year ahead. A decrease of about 3.5 million acres to 83.3 million acres harvested for grain, seems to be a common expectation right now. “With such a reduction and a 2017 U.S. average corn yield near our calculated trend value of 168.8 bushels, the 2017 crop would total 14.06 billion bushels, 1.165 billion bushels less than the 2016 harvest,” he says. “If corn consumption during the 2017-18 marketing year remains at the elevated level of 14.61 billion bushels projected for the current year, stocks at the end of the 2017-18 marketing year would be reduced to about 1.9 billion bushels.”
With a trend yield of 168.8 bushels and a constant level of consumption, any reduction of more than 0.5 million acres would result in some draw down in year-ending stocks of corn during the 2017-18 marketing year, Good says. Conversely, a 3.5 million acre reduction along with a constant level of consumption means that an average yield of less than 174.8 bushels would result in some draw down in marketing year-ending stocks. However, if combined corn production in Brazil and Argentina in 2017 increases by 945 million bushels, as now projected by the USDA, U.S. corn exports would be expected to decline during the 2017-18 marketing year. If U.S. exports decline by 250 million bushels and acreage is reduced by 3.5 million acres, the 2017 average yield would need to be less than 171.8 bushels in order to reduce year-ending stocks.
For soybeans, Good says there is a general expectation that U.S. producers will increase acreage in the year ahead. An increase of about 5 million acres, to 88 million harvested acres, seems to be a common expectation right now. The extremely high soybean yields of the past three years raise some questions about a potential increase in the trend yield. “However, if the 2017 U.S. average soybean yield is near our calculated linear trend value of 47.5 bushels and acreage is increased as expected, the 2017 crop would total 4.18 billion bushels, 181 million bushels less than the 2016 harvest,” he says. “If soybean consumption during the 2017-18 marketing year remains at the elevated level of 4.108 billion bushels projected for the current year, stocks at the end of the 2017-18 marketing year would grow to about 580 million bushels.”
According to Good, with a trend yield of 47.5 bushels and a constant level of consumption, any increase of more than 2.85 million acres would result in some further growth in year-ending stocks of soybeans during the 2017-18 marketing year. On the other hand, a 5 million-acre increase in soybean area along with a constant level of consumption means that an average yield of more than 46.3 bushels would result in some increase in marketing year-ending stocks. However, if combined soybean production in Brazil and Argentina in 2017 increases by 210 million bushels, as now projected by the USDA, U.S. soybean exports would be expected to decline during the 2017-18 marketing year. If U.S. exports decline by 100 million bushels and acreage is increased by 5 million acres, a 2017 average yield of more than 45.2 bushels would result in some increase in year-ending stocks.
“There are obviously multiple potential acreage, yield, consumption, and ending-stocks scenarios for the 2017-18 U.S. corn and soybean marketing year,” Good says. “The most likely scenarios tend to favor a modest reduction in marketing year-ending stocks of corn and a modest to large increase in marketing year-ending stocks of soybeans.
“The corn market currently appears to reflect expectations of reduced stocks, with the December 2017 futures price 37 cents higher than the December 2016 price. The soybean market is apparently not convinced that stocks will continue to grow next year, with the January 2018 future price only 6 cents lower than the January 2017 price. The soybean market appears to be reflecting more production risk than reflected by the corn market. Perceived production risk may stem from current drought conditions in the southeast U.S. and/or uncertainty about potential impacts if a La Niña episode unfolds.”
Get to know chestnuts
URBANA, Ill. – Many Americans only know chestnuts from the famous line, “chestnuts roasting on an open fire,” in the 1945 song, “Merry Christmas to You,” by Bob Wells and Mel Tormé. Prior to its demise in the first half of the 20th century, the American chestnut (Castanea dentata) was one of the largest and most important timber- and nut-producing trees in the eastern United States. In less than a lifetime, the native American chestnut population that spanned the entire Appalachian Mountain range plunged from an estimated 3-4 billion trees to a few hundred survivors. This was all due to the introduction of an exotic Asian bark fungus (Cryphonectria parasitica) growing on the bark of resistant Chinese (C. mollissima) and Japanese (C. crenata) chestnut trees imported by the New York Zoological Park (now known as the Bronx Zoo) for addition to their collection in 1904.
“All types of ‘true’ chestnuts are edible raw or roasted, though roasting is the preferred method, not only for enhanced flavor, but also for ease of peeling the brown skin-like pellicle from the yellowish-white edible kernel of the nut,” says University of Illinois Extension educator Elizabeth Wahle.
Although American chestnuts are considered one of the sweetest tasting chestnuts, its nickel-sized nut is relatively small compared to others. European “sweet” chestnuts (C. sativa) and Chinese chestnuts that now dominate the American market are not considered quite as sweet as the American chestnut, but their larger nut size makes up for this difference. In addition, chestnuts in the genus Castanea interbreed readily, which opens the door for breeding hybrid cultivars with blight resistance and superior nut quality.
But what about those other chestnuts? “Horse-chestnuts or buckeyes (Aesculus spp.) are trees and shrubs unrelated to chestnuts and can be toxic if not prepared properly,” Wahle warns. “There are many similarities between chestnuts and horse-chestnuts and only an experienced and informed forager should collect nuts from the wild for consumption. The water chestnut (Eleocharis dulcis) is not a nut at all, but the corm, or belowground stem, of a grass-like sedge that is grown as a vegetable in aquatic habitats.”
Chestnuts are a highly perishable, high-starch, low-fat food unlike other common tree nuts. For this reason, chestnuts should be purchased close to the time of intended use.
“Choose chestnuts with clean outer shells that are a shiny brown color,” Wahle says. “The tan-colored end of the nuts should be free of mold. The freshest chestnuts are very firm and do not dent when pressed. When cut, the kernel should be yellow. Avoid chestnuts with blue streaking through the kernel, a vinegary smell, or a slimy feel. Chestnuts lose moisture quickly at room temperature and humidity, causing the kernels to dry, harden, and become moldy. To extend the storage life, maintain proper moisture conditions by storing chestnuts in a ventilated plastic bag in the refrigerator and use within a few weeks.
“Because of the high moisture content of the kernel, the outer shell and pellicle must be pierced with a sharp serrated knife, regardless of cooking method. Avoid cutting into the kernel to make shelling easier. A single slit across the widest part of the nut is sufficient to prevent bursting during the cooking process,” Wahle notes.
Chestnuts may be roasted over an open fire for 15-20 minutes with constant motion; roasted in a conventional oven at 300-325°F for 15-20 minutes; boiled or steamed for 10-15 minutes; or microwaved wrapped in damp paper towels for 45-50 seconds on high. “Regardless of the heating process, peeling is easier if nuts are allowed to cool just enough to handle without injury. As nuts cool, peeling the pellicle from the kernel becomes an ever-increasing challenge,” Wahle says.
Chestnuts are not crunchy even when roasted; their texture comes closer to a hard cheese. Although roasted chestnuts can be eaten by the handful, chestnuts can be utilized in a number of culinary endeavors, including flour, thickening for soups, poultry stuffing, nut breads, cakes, puddings, and even wine.
“I hope more Americans get to know chestnuts this holiday season,” Wahle says.
Soybean plants with fewer leaves yield more
URBANA, Ill. - Using computer model simulations, scientists have predicted that modern soybean crops produce more leaves than they need to the detriment of yield—a problem made worse by rising atmospheric carbon dioxide. They tested their prediction by removing about one third of the emerging leaves on soybeans and found an 8 percent increase in seed yield in replicated trials. They attribute this boost in yield to increased photosynthesis, decreased respiration, and diversion of resources that would have been invested in more leaves than seeds.
“The reduction in leaves allows more sun light to penetrate through the canopy making the whole plant more productive, and it also reduces crop water demand,” said the project lead Praveen Kumar, Lovell Professor of Civil and Environmental Engineering at the University of Illinois.
Currently, we only achieve a 1 percent annual increase in yields due to crop improvements, which has slowed in the last decade. “This rate is insufficient to fulfill the needs for global food security, where we need to produce 70-100 percent more food by 2050 to feed an estimated 9.7 billion people,” said project co-lead Steve Long, Gutgsell Endowed Professor of Plant Biology and Crop Sciences at the Carl R. Woese Institute for Genomic Biology at Illinois.
“We are trying to identify non-conventional techniques that can give us a quick boost in yield so that we can get closer to those predicted demands,” said first author Venkatraman Srinivasan, a postdoctoral researcher at Illinois. “Soybeans are one of the four major staple crops and also the most important vegetable protein source in the world. If we can increase the yield of soybeans, we can solve the problems of protein demand and food production at the same time.”
Published in Global Change Biology, their paper found that soybean plants produce too many leaves, most of which are shaded and inefficient, thereby wasting resources like water, carbon and nitrogen. “The model shows that by investing less in leaves, the plant can produce more seeds,” Srinivasan said.
The model predicted that a 30-40 percent decrease in leaf area would increase yields by 8-10 percent in field trials, they decreased leaf area (by manually cutting off new leaflets) by just 5 percent and still increased yields by 8 percent.
“The experiment indicates that that our model is conservative,” Srinivasan said. “We hypothesize that plants with fewer leaves need less water, which requires fewer roots. Cutting down on roots could produce additional carbon savings that the plant can invest towards boosting yield. Alternatively, plants with fewer leaves are more water efficient, and thereby may be potentially drought tolerant.”
Next, the researchers will bioengineer plants or search for varieties that naturally have fewer leaves to test these preliminary findings on a larger scale. They will also continue exploring ways to optimize other aspects of this crop’s canopy of leaves—such as the distribution and angle of leaves—to design better soybean plants that yield more without the need for more water and other resources.
Srinivasan said, “We want to optimize the plant’s canopy structure so that we can get as much photosynthesis as possible out of the crop to increase the food supply.”
This work is part of Realizing Increased Photosynthetic Efficiency (RIPE), a multi-institutional research project that is developing high-yielding crops for farmers in Sub-Saharan Africa and Southeast Asia. Learn more about the project at http://ripe.illinois.edu/.
The paper "Decreasing, not increasing, leaf area will raise crop yields under global atmospheric change" was published in Global Change Biology (DOI: 10.1111/gcb.13526) and is available online or upon request. Funding from the National Science Foundation and RIPE project supported this research.