Corn Ethanol Industry Research Articles

Did the entry of the corn ethanol industry in Brazil affect the relationship between domestic and international corn prices?

AbstractThis study investigates the relationship between corn prices in Brazil and the international market, considering a rise in corn ethanol production in Brazil's Midwest region since 2017. Did the entry of the corn ethanol industry in Brazil affect the relationship between domestic and international corn prices? A cointegration analysis was made with a monthly time series from May 2005 to August 2023 controlling for different exogenous events or shocks that may have affected global agricultural markets. The study's findings indicate a stable long‐term relationship between the international and Brazilian corn prices, with changes in international prices being predictors of variations in Brazilian domestic prices, while the opposite was not statistically supported. The study also found no evidence to support the claim that the entry of the corn ethanol industry into Mato Grosso state in 2017 impacted the prices paid to local producers. Therefore, the increase in Brazilian corn prices cannot be attributed to additional demand for corn by local mills, an important result that contributes to discussions such as food versus fuel and indirect land use change.

Evaluation of Aerobic Propagation of Yeasts as Additional Step in Production Process of Corn Ethanol

Yeast is one of the co-products of ethanol plants, which can be used as a nutritional supplement in animal feed due to its high protein content. Given the importance of yeast contribution to the nutritional properties of DDG (dried distillers’ grains), the aim of this study was to assess how different levels of aeration affect the biomass production and the quality of yeast providing new insights into yeast production, offering an alternative source of income for the corn ethanol industry. For this purpose, yeasts were grown in a fed-batch process, and different concentrations of aeration in the medium were tested, namely 0.5, 1.0, and 1.5 volume of air per volume of wort per minute (v v−1 min−1). At the end of the cellular biomass production process, yeasts grown with 0.5 (v v−1 min−1) aeration in the reactor showed higher biomass formation (19.86 g L−1), cellular yield (g g−1), and a lower formation of succinic acid (0.70 g L−1) and acetic acid (0.11 g L−1). Aeration influenced an increase of 1.0% in the protein content in yeast. In conclusion, lower levels of aeration in the yeast production process enables more efficient sugar utilization for biomass formation and is a potential strategy to increase the protein content and the commercial value of DDG.

Integrated process for a new sequential valorization of corn ethanol production by-products: Production of fermented solid with lipase activity, ethyl esters, and animal feed

The use of co-products from corn ethanol production such as distillers’ dried grains with solubles (DDGS) and distillers’ corn oil (DCO) to produce a crude extract with lipolytic activity and fatty acid ethyl esters was studied in an integrated process. The dry fermented solid (DFS) with lipase activity was produced from the fermentation of the filamentous fungus Rhizomucor miehei in DDGS in tray-type reactors and column systems. The DFS was used to catalyze esterification reactions between oleic acid and ethanol, with conversions of 72% and 80% (within 4 h) for the biocatalyst produced in tray-type and fixed bed systems, respectively. The biocatalyst also converted glycerides from DCO into FAEE, with an ester yield higher than 70% after three consecutive reactions. By introducing 2 wt% of a commercial preparation (Novozym 435) in the system with the DFS, ester contents of 81% were obtained and, the yield was higher than 95% after three consecutive reactions. The biocatalyst could be reused 6 consecutive times in the esterification reactions, after washing with ethanol and 5 times after washing with hexane. In DCO transesterification reactions, reuse was less efficient with a loss of activity after the second reuse. Bromatological analysis showed that the fermented material maintained the main properties of the in natura DDGS, with a reduction in the oil and grease and an increase in protein content. The chemical composition was maintained after its use in the corn oil ethanolysis (used DFS). These findings show the potential for developing novel pathways to diversify the use and enhance the value of co-products derived from the large-scale corn ethanol industry, in a biorefinery concept.

Utilization of co-products from corn ethanol industry in a biorefinery context: a review on the biotechnological potential of thin stillage

Utilization of co-products from corn ethanol industry in a biorefinery context: a review on the biotechnological potential of thin stillage

Exergy, economic and environmental assessment of a hybrid solar-biomass cogeneration plant applied to the corn ethanol industry

Exergy, economic and environmental assessment of a hybrid solar-biomass cogeneration plant applied to the corn ethanol industry

Volumetric Scale-Up of a Packed-Bed Ion-Exchange System to Extract Phytate from Thin Stillage.

Phytate is the main form of phosphorus in corn ethanol coproducts and poses digestion issues in monogastric-animal feed. Extracting phytate as a commodity chemical will bring extra revenue to the corn ethanol industry and reduces potential phosphorus pollution from livestock waste management. We assessed a simplified scale-up approach of an ion-exchange separation system applied to extract phytate from thin stillage using volumetric parameters and simplifications of the van Deemter model. Thin stillage is one of the main byproducts generated on dry-grind corn-to-ethanol plants and accounts for the liquid portion of the bottom product generated in the ethanol distillation process. Thin stillage is rich in dissolved phytate, which served as the basis for an ion-exchange extraction system developed with a scalability factor of 50. Under the evaluated conditions, similar breakthrough profiles were obtained when similar Péclet and Stanton numbers were maintained for the scales studied, demonstrating that a simple and straightforward scale-up can be attained if special attention is given to maintaining both parameters as the basis of calculations of the plate numbers of ion-exchange columns.

Green Composites from a Bioplastic Blend of Poly(3-hyroxybutyrate-co-3-hydroxyvalerate) and Carbon Dioxide-Derived Poly(propylene carbonate) and Filled with a Corn Ethanol-Industry Co-product.

Sustainable green composites were engineered from distillers’ dried grains with solubles (DDGS), a co-product from the corn ethanol industry as a sustainable filler in bioplastic matrices made from a carbon dioxide-derived poly(propylene carbonate) (PPC) and poly(3-hyroxybutyrate-co-3-hydroxyvalerate) (PHBV) blend. The effect of water-washed DDGS (15 and 25 wt %) on the properties of injection-molded green composites from PHBV/PPC blends (60/40) and (40/60) and DDGS without and with peroxide (0.5 phr) has been investigated. From the results, it was noticed that the glass transition temperature (Tg) of the PHBV/PPC (60/40) bioplastic matrix increased by ∼9.6 °C by adding a peroxide cross-linking agent, indicating significant interaction (linkage) between PHBV and PPC polymers in this particular composition ratio, which was supported by SEM analysis as no phase separation was observed between PHBV and PPC. The tensile modulus of PHBV/PPC (60/40) and PHBV/PPC (40/60) blends with peroxide was improved by ∼40.7 and 1.5% after the addition of 25 wt % DDGS, respectively, due to its fibrous flaky structure. The % elongation values at break of the PHBV/PPC (60/40) blend matrices with and without peroxide were drastically improved by 18.5 and 90.7 folds, respectively, as compared to that of brittle pristine PHBV.

Effects of Replacing Yellow Corn with Olive Cake Meal on Growth Performance, Plasma Lipid Profile, and Muscle Fatty Acid Content in Broilers.

Simple SummaryYellow corn is a grain frequently utilized in broiler diets. Moreover, the new era of the corn-ethanol industry for biofuel production has increased the divergence of energy applications of corn. These uses have considerably increased corn prices over the past few years. Using byproducts may be one of solutions to this problem. Olive cake meal (OCM) is a byproduct obtained from olive oil factories after olive oil is extracted. It has a high nutritional value, especially in regard to metabolizable energy. OCM has been used successfully in livestock and poultry feeding as an alternative to energy sources such as corn, without any adverse effects on performance. Hence, the current study investigated the effects of replacing yellow corn with OCM on the growth, nutrient utilization, selected blood parameters, and muscle fatty acid profile of broilers. Four hundred and eighty one-day-old male broiler chickens (Ross 308) were divided into four experimental groups (a control group, and groups with 5%, 10%, and 20% of corn replaced with OCM). The results revealed that replacing 10% of corn with OCM in the diet improved growth performance and reduced abdominal fat and liver malondialdehyde (MDA) and increased high density lipoprotein (HDL).The current study focused exclusively on evaluating the effects of replacing corn with olive cake meal (OCM) in the diet of broilers on their growth performance, abdominal fat, selected plasma parameters, and muscle fatty acid (FA) content. A total of 480 one-day-old male broiler chickens (Ross 308) were divided into four treatment groups with 12 replicates/treatment. The control group was fed the base diet, whereas the second to fourth groups were fed diets of corn with 5%, 10%, and 20% contents of OCM, respectively. Broilers fed with the 5% and 10% OCM diets showed better body weight (p = 0.04) and feed conversion ratio than the 20% OCM group (p < 0.048). Both nitrogen retention and ether extract digestibility were not improved by replaced corn with OCM. Replacing corn with OCM led to a decreased abdominal fat percentage (p = 0.023) compared with the control group. Birds in the OCM groups showed the lowest total cholesterol values (p = 0.038). The breast muscle (musculus pectoralis superficialis) content of oleic and linoleic, linolenic, and arachidonic acids was significantly high in birds fed with OCM diets. However, their palmitic acid level was significantly decreased. Vitamin E was increased by increasing the OCM level. Thus, we concluded that replacing corn with OCM, especially at a 10% level, is more effective than other replacement levels in improving growth performance, plasma lipid profile, and muscle FA content, as well as in causing a reduction in abdominal fat in broilers.

Retrospective analysis of the U.S. corn ethanol industry for 2005–2019: implications for greenhouse gas emission reductions

AbstractSince 2000, corn ethanol production in the USA has increased significantly – from 1.6 to 15 billion gallons (6.1 to 57 billion liters) – due to supportive biofuel policies. In this study, we conduct a retrospective analysis of the changes in US corn ethanol greenhouse gas emission intensity, sometimes known as carbon intensity (CI), over the 15 years from 2005 to 2019. Our analysis shows a significant decrease in CI: from 58 to 45 gCO2e/MJ of corn ethanol (a 23% reduction). This is due to several factors. Corn grain yield has increased continuously, reaching 168 bushels/acre (10.5 metric tons/ha, a 15% increase) while fertilizer inputs per acre have remained constant, resulting in decreased intensities of fertilizer inputs (e.g., 7% and 18% reduction in nitrogen and potash use per bushel of corn grain harvested, respectively). A 6.5% increase in ethanol yield, from 2.70 to 2.86 gal/bushel corn (0.402 to 0.427 L kg−1 corn), and a 24% reduction in ethanol plant energy use, from 32 000 to 25 000 Btu/gal ethanol (9.0 to 6.9 MJ L−1 ethanol) also helped reduce the CI. The total GHG emission reduction benefits through the reduction in the CI and increased ethanol production volume are estimated at 140 million metric tons (MMT) from 2005 to 2019 in the ethanol industry. Displacement of petroleum gasoline by corn ethanol in the transportation fuel market resulted in a total GHG emission reduction benefit of 544 MMT CO2e during the period 2005 to 2019. © 2021 Argonne National Laboratory. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley &amp; Sons Ltd

Effects of drying temperatures and storage conditions on the levels of lipids and starches in corn grains for yield ethanol industry

Post-harvest operations can reduce changes in the physical-chemical quality of processed grains. Thus, this study aimed to evaluate the effects of drying and storage conditions on the lipids and starches content in corn grains correlating ethanol production. In the results obtained, the adjustment of the drying curves associated with physical analyses made it possible to verify that the increase in temperature affected the grains’ cell tissues and reduced lipids, starches, and the industrial yield of ethanol for 0.032 L kg−1 of grains. Besides, the corn storage under refrigeration was favorable to maintaining the levels of lipids (+1.42%), starch (+1.33%), and ethanol yield (+0.017 L kg−1 of grains). In conclusion, the drying temperature at 40 °C and the controlled storage at 15 °C preserved the corn grain quality over the six months and positively influenced the grain processing quality. The adverse environmental conditions associated with the post-harvest technologies do not guarantee the quality of the corn grains used for the processing industry. In the current Brazilian situation, the corn ethanol industry improvement involves the application of low temperature in drying systems and the storage of corn in controlled environments.

Pyrolyzed biomass from corn ethanol industry coproduct and their polypropylene-based composites: Effect of heat treatment temperature on performance of the biocomposites

This study targets the value-added engineering applications of Distillers’ dried grains with solubles (DDGS), a co-product from corn ethanol industry in lightweight biocomposites. The DDGS derived carbonaceous materials produced through torrefaction and pyrolysis were used as fillers for the manufacture of polypropylene (PP) based biocomposites. A systematic study was conducted for the first time in scientific literature in which the DDGS was heat treated from 100 to 1000 °C (torrefaction; 200–300 °C and pyrolysis; 400–1000 °C) and used in the biocomposites with a fixed 30 wt % content. With increase in temperature of pyrolysis, the functional groups of the filler were removed, and the ash content was increased. The biocomposites showed their best performance in terms of stiffness-toughness balance with biocarbon pyrolyzed at 700 °C, because of its non-polarity compared to the DDGS_400 °C, and lower ash content and particle size than the DDGS_1000 °C. Comparatively improved compatibility between the DDGS_700 °C and PP resulted in higher complex viscosity and storage modulus than the rest of biocomposites. Overall, this study shows the importance of understanding and optimizing the heat treatment temperature for the production of biocarbon used as a filler in biocomposites based on the specific properties, application, yield, and hence cost effectiveness of the filler.

Effects of Energy Cane (Saccharum spp.) Juice on Corn Ethanol (Zea mays) Fermentation Efficiency: Integration towards a More Sustainable Production

Despite being considered renewable, corn (Zea mays) ethanol still generates much debate over the use of fossil fuels in its production and is considered less sustainable than sugarcane (Saccharum spp.) ethanol. In Brazil, corn ethanol is starting to be produced in the Center-West and is expected to increase with the RenovaBio, a promising policy for biofuels adoption. In this context, energy cane (Saccharum spp.) is a biomass crop with high yields that can provide bagasse to supply the energy demand of the corn ethanol industry and provide juice with about 10% sugar content. However, the effects of introducing its juice in the production process are unknown. For these reasons, the objective of this study was to assess the effects of adding energy cane juice in corn ethanol production. Energy cane juice brings several advantages: (i) It provides sugars that can reduce by almost 50% the amount of corn and enzymes used, (ii) reduces the amount of water needed for ethanol production, and (iii) increases significantly the fermentation efficiency from 86.4% to 90.8% by providing minerals that support yeast growth. Therefore, energy cane can be integrated into the corn ethanol production process, making the fermentation more efficient and the production systems more sustainable.

Effects of corn distillers dried grains on dough properties and quality of Chinese steamed bread.

Chinese steamed bread (CSB) accounts for 30% of the wheat end‐use in China. CSB was studied as a platform for fiber and protein enrichment, employing corn distillers dried grains. Food grade distiller's grain (FDDG) processed from co‐products from the corn ethanol industry was used as the enrichment ingredient. Since CSB uses a lean formula with little or no added sugar or fat, it relies entirely on fermentation and steaming for flavor and texture development. FDDG was used to replace 0%–25% all‐purpose flour (APF) in CSB formulations. Effects of FDDG on dough properties and quality of CSB were evaluated by instrumental (Farinograph, Mixolab, and Texture Analyzer), nutritional, and sensory methods. Protein and dietary fiber contents showed significant increases to 18.8% and 15.3%, respectively, for 100 g of steamed bread (25% FDDG db). Fiber in 100 g of fresh FDDG CSB ranged from 2.8 to 7.7 g. FDDG fortified doughs demonstrated higher water absorption, while dough development time, dough stability, and dough extensibility decreased significantly with partial APF replacement. FDDG contributed to increased hardness and adhesiveness in the CSB. Crumb analysis revealed reduced number of gas cells at higher FDDG substitution. FDDG enrichment reduced brightness (L*) of flour blends and CSB. Rheological and sensory analysis showed an upper level of FDDG substitution of 15% was acceptable without detriment to dough functionality, texture, and taste.

Quantification and purification of lutein and zeaxanthin recovered from distillers dried grains with solubles (DDGS)

Marigold petals, the current commercial source for lutein and zeaxanthin are harvested through a labor-intensive operation with downstream purification requiring multiple processing steps involving various harsh solvents. Lutein and zeaxanthin are in-demand carotenoids due to their significant role in human eye health. A possible alternative source for lutein and zeaxanthin, distillers dried grain with solubles (DDGS), shows promise and contains a yet-to-be quantified amount of the desired carotenoids. The US corn industry produces an abundant, and in some cases excess, annual supply of DDGS. The large volume of DDGS produced could serve as a significant source for lutein and zeaxanthin recovery and provides an additional market stream for the growing carotenoid industry. This paper demonstrates one of the first quantitative reports regarding the concentration of lutein and zeaxanthin in DDGS. Using Soxhlet extraction, followed by purification with centrifugal partition chromatography, it was determined that 36.09 ± 16.87 µg lutein and 15.48 ± 6.13 µg zeaxanthin could be purified from all extractives retained in the oleoresin per gram of DDGS. As compared to lutein and zeaxanthin present in corn, this is a three to fivefold increase indicating that these compounds become concentrated during the dry grind process. Recovery of lutein and zeaxanthin from DDGS, a low-value stream by-product of corn ethanol industry, results in a new revenue stream and would add value to a common US commodity.

Effects of low concentrations of erythromycin, penicillin, and virginiamycin on bacterial resistance development in vitro

Distillers grains are co-products of the corn ethanol industry widely used in animal feed. We examined the effects of erythromycin, penicillin, and virginiamycin at low concentrations reflective of those detected in distillers grains on bacterial resistance selection. At 0.1 µg/ml erythromycin, macrolide-resistant mutants were induced in one Campylobacter coli and one Enterococcus faecium strain, while these strains plus three additional C. coli, one additional E. faecium, and one C. jejuni also developed resistance when exposed to 0.25 µg/ml erythromycin. At 0.5 µg/ml erythromycin, a total of eight strains (four Campylobacter and four Enterococcus) obtained macrolide-resistant mutants, including two strains from each genus that were not selected at lower erythromycin concentrations. For penicillin, three of five E. faecium strains but none of five Enterococcus faecalis strains consistently developed resistance at all three selection concentrations. Virginiamycin at two M1:S1 ratios did not induce resistance development in four out of five E. faecium strains; however, increased resistance was observed in the fifth one under 0.25 and 0.5 µg/ml virginiamycin selections. Although not yet tested in vivo, these findings suggest a potential risk of stimulating bacterial resistance development in the animal gut when distillers grains containing certain antibiotic residues are used in animal feed.

Corn‐Ethanol Plant Investment: A Real Options Case Study

The objective of this article is to describe an investment decision using net present value and real options. A case study describes the data and the corn‐ethanol industry so students can study a cooperative's decision of whether or not to invest in a new corn‐ethanol plant in 2015 Nebraska. An extensive set of information accompanies this case, including spreadsheets with data, computer software code, lesson plans for teaching real options and net present value, and an extensive teaching note.

Enzymes threatened by biotech corn

Enzyme companies have thrived in recent years by replacing synthetic chemicals in applications such as laundry detergents, animal feed, and textile manufacturing. Now, however, makers of enzymes are getting a taste of their own medicine. Sales of α-amylase to the corn ethanol industry are threatened by a new kind of corn genetically engineered to contain the enzyme. The corn, called Enogen, was developed by the agriculture giant Syngenta. Ethanol producers traditionally buy α-amylase to break down cornstarch into sugar, which is then fermented into ethanol. Now, instead, they can buy enzyme-containing corn from farmers by paying them a 40-cent-per-bushel premium. Introduced in 2011, Enogen was slow to catch on. But today, Syngenta says, some 20 ethanol plants across the U.S. are running on it. In a new report, the investment firm Jefferies estimates that more than 10% of U.S. ethanol plants have adopted Enogen and that another 15–20% of them

Evaluation of green solvents for a sustainable zein extraction from ethanol industry DDGS

Corn-ethanol industry in US alone generates about 35 Tg of Dried Distillers Grains with Solubles (DDGS) per year as co-product. DDGS is enriched with zein, a well-known corn protein. Vast potential of zein application in industries ranging from pharmaceuticals to bio-plastics resulted in a serious quest to develop process technologies for its extraction. A broad spectrum of primary, binary, ternary and tertiary solvents is available which can extract zein from DDGS. But most organic solvents are hazardous which limits their sustainable industrial-scale use. Our study evaluated green solvents: isopropanol, n-butanol, isobutanol, 2,3-butanediol (2,3-BDO), 1,4-butanediol, isoamyl alcohol, 1,3-dioxolane, 1,4-dioxane, tetrahydrofuran, acetic acid, lactic acid and ionic liquids [emim]Ac and [emim]Br for zein extraction. Isopropanol, 1,4-dioxane and 2,3-BDO showed promising results, with 75, 41 and 38% extraction efficiency, respectively. Operational parameters for efficient extraction such as temperature, pH and solvent-to-water ratio were subsequently optimized using response surface methodology for selected solvents. A combination of solvent to water volume ratio of 66:34, temperature of 77 °C and pH of 4.4 was found to be optimal for isopropanol, whereas 2,3-BDO worked best at solvent to water volume ratio of 73: 27, temperature of 85 °C and pH of 3.8. These results are encouraging and could lead to the development of green technology for efficient zein extraction.

Performance of an anaerobic fluidized bed bioreactor (AnFBR) for digestion of primary municipal wastewater treatment biosolids and bioethanol thin stillage

The primary objective of this work was to investigate and compare the treatability of very high suspended solids with different biodegradable particulate fractions and COD fractionation, thin stillage (a by-product from the corn ethanol industry) as well as primary sludge from municipal wastewater treatment, using an anaerobic fluidized bed bioreactor (AnFBR) employing US Mesh 30 × 40 zeolite with a diameter of (dm) in the range of 425–610 μm and specific surface area (SSA) of 26.5 m2/g as the carrier media. Each experimental run lasted over a six-month period. Due to the long-term impact of accumulation of inert suspended solids in the AnFBR and potential active biomass washout leading to failure, treatability of high suspended-solid streams can be very challenging. Despite the very high strength of thin stillage and primary sludge with chemical oxygen demand of 130,000 mg TCOD/L and 42,000 mg TCOD/L respectively and suspended solids of 47,000 mg TSS/L and 34,000 mg TSS/L, the AnFBR showed, up to 88% and 82% TCOD and 78% and 82% TSS removal efficiencies from thin stillage and primary sludge respectively at very high organic and solids loading rates (OLR and SLR) of 29 kg COD/m3 d and 9.5 kg COD/m3 d and 10.5 kg TSS/m3 d and 10.3 kg TSS/m3 d respectively at hydraulic retention time (HRT) of 3.5 and 4 days. Maximum methane production yields of up to 0.31LCH4/gCOD and 0.25LCH4/gCOD were achieved for thin stillage and primary sludge respectively corresponding to biogas production rate per reactor volume of 15.8 Lgas/Lreactor d and 1.22LCH4/Lreactord.

Vacuum Stripping of Ethanol during High Solids Fermentation of Corn

In corn-ethanol industry, yeast stress inducing glucose concentrations produced during liquefaction and subsequent high ethanol concentrations produced during fermentation restrict slurry solids to 32 % w/w. These limits were circumvented by combining two novel technologies: (1) granular starch hydrolyzing enzyme (GSHE) to break down starch simultaneously with fermentation and (2) vacuum stripping to remove ethanol. A vacuum stripping system was constructed and applied to fermentations at 30, 40, and 45 % solids. As solids increased from 30 to 40 %, ethanol yield decreased from 0.35 to 0.29 L/kg. Ethanol yield from 45 % solids was only 0.18 L/kg. An improvement was conducted by increasing enzyme dose from 0.25 to 0.75 g/g corn and reducing yeast inoculum by half. After improvement, ethanol yield from 40 % solids vacuum treatment increased to 0.36 L/kg, comparable to ethanol yield from 30 % solids (control).