Corn Ethanol Research Articles

Zymomonas mobilis is an α-proteobacterium that ferments simple sugars to produce ethanol, to near perfect yields. Corn ethanol and 2nd generation cellulosic ethanol continue to dominate the biofuels domain. Given the global mandate for cleaner, safer and renewable energy, Z. mobilis has been rigorously studied in academia and in industry as a platform organism for the production of 1st and 2nd generation bioethanol, for over three decades. In order to optimize Z. mobilis, of interest to us has been the understanding of the Z. mobilis genome – core and pangenome – to a comparative, structural and functional level. To this end, we have sequenced different strains that were obtained from various parts of the globe, as well as transcriptomes harvested at different growth conditions. This genomic endeavour has helped us recognize the collective gene pool, discriminate essential from accessory genes, observe genomic division between chromosomal and extrachromosomal elements, and gain evidence for gene flows and horizontal transfer events. It has also enabled us to choose the most suitable modules – genes or cis-acting elements – in order to enhance the bacterium’s performance and/or create designer strains. Gene networks contributing to cell-cell signalling and mutagenic stress have also been of interest. In terms of elucidating responses brought forth by a mutagenic stressor, transcriptional profiling has been carried out and revealed the vast numbers of genes implicated in SOS induction, in DNA repair and cell-cycle regulation, as well as other versatile functions, expected or unforeseen. Lastly, we undertook to complement the otherwise truncated TCA cycle of this bacterium and inquired on concurrent metabolomic profile changes as well as productivity. The suitability of the newly constructed TCA-proficient strain for future biorefinery use is under further investigation.

This study adopts the 5W2H management tool to investigate the opportunities and challenges of enzymatic biodiesel production from residual oils. The methodological approach enables a structured evaluation of technical, economic, environmental, and governance aspects, clarifying critical conditions for feasibility and scalability. To illustrate this framework, the research applies it to the Brazilian biofuel sector, focusing on the valorization of Distillers Corn Oil (DCO), a by-product of corn ethanol production not intended for human consumption. Results show that enzymatic conversion of DCO can reduce feedstock costs by more than 50% and energy demand by up to 86.8% compared with conventional chemical processes. Nevertheless, the scalability of this technology faces critical barriers, such as enzyme costs, reaction times, and regulatory uncertainties. The study concluded that public–private partnerships and targeted policies, such as those under Brazil’s National Biodiesel Program (PNPB), are essential to overcoming these challenges and bridging the “valley of death” toward commercialization. By combining technical, economic, and governance perspectives, the study demonstrates that DCO-based enzymatic biodiesel has the potential to reinforce Brazil’s role in the global biofuels market while promoting a circular and sustainable energy transition.

The research presented in the article is aimed at developing reference materials (hereinafter referred to as RMs) for the isotopic composition of ethanol required for measurements in accordance with the requirements of Russian standards and Technical Regulations of the Customs Union. The relevance is due to the expansion of the scope of isotope analysis in various fields, including the food industry, environmental monitoring and customs control. Current reference materials have a limited range of certified values and are not available in Russia due to the imposition of sanctions by unfriendly countries, which creates the need to develop domestic analogues.The purpose of the research is to create and subsequently certify the metrological characteristics of reference materials for the isotopic composition of ethanol obtained from various raw materials: corn, wheat, sugar beet and synthetic ethanol. For this purpose, a method for preparing reference materials was developed, a pilot batch was produced, tests for homogeneity, long-term and short-term stability were performed, and certified values of the isotopic composition of carbon, oxygen and hydrogen were determined.The main methods of RM production and certification included isotope mass spectrometry using the Isoprime precisION isotope mass spectrometer (hereinafter referred to as IMS), automated packaging and sealing of ampoules with reference materials. The study of metrological characteristics showed high homogeneity and stability of the developed reference materials, which confirms their suitability for metrological purposes. The certified values of the developed reference materials are consistent with known literature data on the isotopic composition of plant-based ethanol (corn and wheat), which confirms the reliability of isotopic analysis methods and their applicability for identifying biological sources of alcohol. The novelty of the research work lies in the development of domestic reference materials with a wider range of certified values of the isotopic composition of carbon, oxygen and hydrogen compared to analogues, which extends the capabilities of accurate measurements and control in various industries.The practical significance of the research is the development of new reference materials for quality control of alcoholic products, customs control and state control in the alcohol market. The developed reference materials provide accurate determination of the origin of ethanol, which is especially important for the identification of biological and synthetic sources.The research results create opportunities for developing reference materials of other substances, such as calcium carbonate, polyethylene and carbon monoxide.

The United States (US Mid-Atlantic Region (MAR) has the potential to grow a variety of perennial feedstocks such as switchgrass and shrub willow to increase domestic energy production. These cellulosic feedstocks have also shown improved ecosystem services, such as soil carbon sequestration, nitrate leaching reduction, and flood mitigation along rivers and streams as partially harvested riparian buffers. To examine the effects on greenhouse gases (GHGs) and criteria air pollutants (CAPs) from using these feedstocks to produce ethanol or electricity, we conducted a comprehensive life cycle assessment (LCA) and estimated the impact on human health costs when land use is changed from corn production for ethanol. Results indicate up to 54% reduced GHG per hectare from using willow and switchgrass feedstock sources to produce ethanol instead of corn. However, there was a trade-off in terms of CAP emission, as grass-based energy emitted more NOx and SOx compared to the corn ethanol pathway, except for SOX emissions from willow-based electricity. Electricity from cellulosic biomass had higher particulate matter (PM) emission compared to that from corn ethanol. Estimates for health cost to society ranged from $2498 ha-1 for electricity from switchgrass to a net benefit of $448 ha-1 for ethanol production from willow, depending on varying biomass yield under different market scenarios. Although using cellulosic feedstocks to produce bioenergy has great potential to reduce GHG emissions, CAP control measures are needed to manage CAP-induced health costs.

Cradle-to-Gate greenhouse gas emissions of the production of ethylene from U.S. Corn ethanol and comparison to fossil-derived ethylene production.

Context Distillers grains can be used in ruminant diets as sources of protein and energy. Recent technology has allowed to remove the fiber of the corn grain before fermentation. Fiber can be combined with condensed distillers solubles to obtain other new ethanol byproducts, such as dry fiber plus solubles (DFS). The animal response to new byproducts needs to be evaluated. Aims This study aimed to evaluate the effects of DFS and dry distillers grains plus solubles (DDGS) on feed intake, digestibility, performance, and blood metabolites of growing beef cattle, to partially replace ground corn and completely replace soybean meal and cottonseed cake in non-forage diets. Methods Twenty-four young Nellore bulls (initial body weight of 276 ± 37 kg, and age of 12 ± 3 months) were randomly distributed into 12 pens, using a completely randomized block design. Treatments were: (1) CON – control diet with conventional ingredients (soybean hulls, ground corn, soybean meal, cottonseed cake, urea and mineral mix; CP in diet = 148 g/kg); (2) DFS – diet with inclusion of 30% DFS (CP in diet = 143 g/kg); and (3) DDGS – diet with inclusion of 30% DDGS (CP in diet = 185 g/kg). The CON diet was formulated to an average daily gain (ADG) of 0.8 kg. Keys results The inclusion of DFS and DDGS increased dry matter intake (DMI; kg per animal per day) compared with CON diet (P = 0.021); however, DMI was not affected when measured in g per kg BW (P > 0.05). The CP, ether extract (EE) and NDF intake were highest for DDGS, intermediate for DFS and lowest for CON (P < 0.010). The inclusion of DFS and DDGS improved nutrient digestibility compared to the CON diet (P < 0.05). The ADG and feed conversion were higher (P < 0.05) for the animals receiving the DDGS compared to CON and DFS, which did not differ from each other. The total predicted metabolizable protein supply was highest for DDGS, intermediate for DFS, and lowest for CON (P < 0.001). Treatments showed no effects on serum indicators (P > 0.05), though trends were observed for urea (P = 0.070) and albumin (P = 0.087) levels. Conclusions The inclusion of 30% DDGS supports greater productive performance, likely due to the increased supply of nutrients, particularly metabolizable protein and net energy. Implications Corn ethanol byproducts (DDGS and DFS) can completely replace protein sources and partially replace corn in non-forage diets.

Abstract We quantify the impact of soybean oil‐based biodiesel production on US cropland, using a method that accounts for the intermediate effect of soybean crushing facilities. Based on U.S. Environmental Protection Agency data for biodiesel production and proprietary data for soybean crushing facilities over 2011–2020, we find that the elasticities of soybean acreage and total cropland acreage with respect to soybean oil‐based biodiesel production are 0.011 and 0.002, respectively. The direct land‐use effect of soybean oil‐based biodiesel is about 0.96 million acres of cropland expansion per billion gallons, about twice as high as some estimates for corn ethanol from previous studies.

The objective was to evaluate the inclusion of three corn ethanol byproducts in finishing cattle diets: high protein distillers grain (HPDG) was used as a source of protein in the diet to entirely replace whole cottonseed and soybean meal, dry fiber plus solubles (DFS) and wet fiber plus solubles (WFS) were used as energy-protein sources in the diet to replace a portion of the corn and entirely replace whole cottonseed and soybean meal from the conventional diet. Diets were formulated to be isonitrogenous with all diets containing 15% corn silage, 12% soybean hulls, 0.55 to 0.85% urea, and 1.80% mineral and vitamin supplements on dry matter (DM) basis. The treatments were (% DM): 1) control (CON): 8% whole cottonseed, 5% soybean meal, and 57.6% ground corn; 2) HPDG: 10.3% HPDG and 60.35% ground corn; 3) DFS: 30% DFS and 40.35% ground corn; 4) WFS: 30% WFS and 40.35% ground corn. Pre-planned contrasts included CON diet vs. HPDG diet, CON diet vs. DFS diet, and CON diet vs. WFS diet. In Exp. 1, 258 Nellore bulls were blocked by initial shrunk body weight (BW; 423 kg ± 36.6 kg), allocated into 44 pens in a randomized complete block design, and fed for 102 d. The average daily gain was greater (P = 0.02) for DFS than CON. Final BW (P = 0.02), hot carcass weight (HCW; P < 0.01), and Longissimus muscle area (P = 0.03) were greater for DFS than CON. In Exp. 2, 4 ruminally cannulated Nellore steers (initial BW = 389 ± 37 kg) were used in a Latin square design. Steers fed the WFS diet had less (P = 0.01) DMI than CON steers. The ether extract intake was greater (P = 0.02) for DFS and tended (P = 0.09) to be greater for WFS than CON, but HPDG did not differ from CON (P = 0.22). Steers fed DFS diets had 39.9% greater neutral detergent fiber intake (P < 0.01) than CON. Digestibility of DM was less (P < 0.01) for DFS than CON. Feeding HPDG and DFS decreased (P < 0.01) the molar proportion of rumen acetate, increased (P < 0.01) rumen propionate, and decreased acetate:propionate ratio (P < 0.01) compared to CON. Ruminal pH was not affected (P ≥ 0.82) by treatments, while ruminal ammonia nitrogen was greater for CON (P ≤ 0.01) compared with HPDG, DFS, and WFS. Feeding HPDG was a viable protein supplement alternative to sources like whole cottonseed and soybean meal in finishing diets. Feeding WFS and DFS improved cattle performance by displacing a portion of the flint corn and entirely replacing whole cottonseed and soybean meal.

United States (US) croplands are ideal recipient environments for solar photovoltaic (PV) energy because they are flat and have a high solar resource. Perceived threats of solar to agriculture have led some stakeholders to suggest that croplands be exclusively used to produce food. However, 12 million hectares of US croplands, an area about the size of New York State, are already dedicated to corn grown for ethanol (i.e., biofuel), an energy product that requires significantly more land than solar PV per unit energy. Ecosystem service benefits of an ecologically informed approach to solar development (i.e., ecovoltaics), coupled with significant land-use advantages over corn ethanol, make solar an attractive solution for a sustainable energy transition in croplands. Here, we evaluated how the conversion of a small fraction of corn-ethanol croplands into ecovoltaic solar facilities might improve land-use efficiency of energy generation, enhance ecosystem services, and provide landscape diversification. Through spatial analyses, we determined that converting just 3.2% of land currently used for corn ethanol would increase the share of utility-scale solar energy in the US from 3.9 to 13%. We also identified target locations where strategic conversion of corn ethanol to solar PV colocated with perennial vegetation could filter excess nutrients transported from adjacent farm runoff, diversify and connect agricultural landscapes, and provide local wildlife habitat. In contrast to the common perception of land-use competition and land scarcity in the energy transition, our findings highlight benefits of colocated energy landscapes that integrate fundamental principles of energy development and sustainable agroecosystems.

Abstract This study evaluated a commercial technology for producing low‐ or negative‐carbon hydrogen through ethanol catalytic oxidative reforming, focusing on the life cycle greenhouse gas emissions, or carbon intensity (CI). Various scenarios were analyzed: (a) comparing corn ethanol (first‐generation or Gen1 ethanol) and cellulosic ethanol (second‐generation or Gen2 ethanol) as feedstocks; (b) assessing carbon capture and sequestration (CCS) for CO2 from upstream fermentation; and (c) evaluating oxygen sourcing via air separation units vs. on‐site or off‐site water electrolysis using a proton exchange membrane. Findings indicate that the CI for hydrogen production using Gen2 ethanol from corn stover is lower than that of Gen1 corn ethanol. Additionally, using proton exchange membrane‐generated oxygen results in a lower CI than air separation unit‐generated oxygen, regardless of the sourcing method. Implementing CCS for the hydrogen production plant's evolved CO2 is essential for achieving a net‐negative CI for hydrogen from Gen1 ethanol. All examined scenarios, including both ethanol generations, oxygen sources, and CCS applications, demonstrated a net‐negative carbon intensity, surpassing the life cycle greenhouse gas emissions threshold of 0.45 kg CO2e/kg to enable policy credits as outlined in the Inflation Reduction Act §45V. In comparison, the CI for hydrogen from steam methane reforming stands at 3.4 kg CO2e/kg with CCS and 9.4 kg CO2e/kg without CCS.

Corn protein (CP), a co-product of the corn ethanol industry, is a sustainable protein source used in pet foods. The objectives of this study were to determine the palatability and apparent total tract digestibility (ATTD) of diets containing CP and to test the effects of CP-containing diets on the serum metabolites, hematology, and fecal characteristics, metabolites, and microbiota of healthy adult dogs. Ten female adult beagles (mean age: 6.12 ± 1.39 yr; mean body weight: 9.33 ± 1.04kg) were used in a replicated 5 × 5 Latin square design (n = 10/treatment). All dietary treatments were based on brewers rice, low-ash chicken byproduct meal, and chicken fat, and contained variable amounts of corn-based proteins: 0% (control), 15.3% corn gluten meal (CGM), 10.2% CGM + 5% CP (Low), 5.1% CGM + 10% CP (Medium), and 15% CP (High). The experiment was composed of five 28-d periods, with each consisting of a 22-d diet consumption period, a 5-d fecal collection period, and 1 d for blood collection. Data were analyzed statistically by Mixed Models using SAS 9.4, with P < 0.05 accepted as being statistically significant. Two 2-d palatability studies (n = 20 dogs) were also conducted to compare the High diet vs. control diet and High diet vs. CGM diet. Dogs were shown to prefer (P < 0.05) the High diet over the control diet by a ratio of 1.8:1, but no preference was observed between the High and CGM diets. In the digestibility study, the ATTD of dry matter, organic matter, and energy increased (P < 0.001) linearly with CP inclusion. The ATTD of fat was greater (P < 0.001) for the control diet than for the CGM, Low, and High diets. Fecal scores were lower (P = 0.05; firmer) and fecal dry matter percentage was higher (P < 0.0001) in dogs fed CGM than those fed CP. Fecal phenol and indole, short-chain fatty acid, and branched-chain fatty acid concentrations were greater (P < 0.05) in dogs fed CP than dogs fed CGM and control. Fecal bacterial diversity was not altered by diet, but the relative abundance of approximately 10 bacterial genera was altered by diet. In summary, our data demonstrate that the inclusion of CP in dog foods resulted in high diet palatability and macronutrient digestibility and altered microbial composition and activity.

Effects of Alkaline Pretreatment with Sodium Hydroxide with and Without Anthraquinone on the Enzymatic Hydrolysis of Corncob and Corn Stover and Ethanol Production

This study aimed to evaluate the chemical composition of tropical grass silage with added co-products from the production of corn ethanol, dried distillers’ grains (DDG) and wet distillers’ grains (WDG), and grass intercropped with corn. The estimation of the chemical composition was performed with near-infrared reflectance spectroscopy (NIRS). In Experiment I (elephant grass), the experimental design was completely randomized with four replicates, and treatments were arranged in a 2×6 factorial scheme with two factors (additives: DDG and WDG, and application levels: 0, 5, 10, 15, 20, and 30%). In Experiment II (Tanzania grass), the experimental design was completely randomized with four replicates, and the treatments included five DDG levels (0, 5, 10, 15, and 20%). In Experiment III, the experiment was conducted in randomized blocks with five replicates, and the treatments were organized in a 2×4 arrangement. Factor 1 included two cultivation methods, monocropped corn and corn intercropped with ruziziensis grass, and factor 2 involved four parts of the corn plant: whole plant, half plant, cobless plant, and cob with husk. The dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid (ADF), ash, and estimated total digestible nutrient (TDN) contents were evaluated. Reference values were added to the spectra of forage samples. Data preprocessing and chemometric model building, that is, calibration curve development, were performed using the Opus 7.5 software employing partial least squares (PLS) regression. The calibration model was selected based on the lowest root mean square error of the cross-validation (RMSECV) and the highest coefficient of determination (R2cv). The nutritive value of elephant grass and Tanzania grass silage improved with the use of DDG when compared with that of in natura silage. The NDF and ADF contents were lower, and DM was higher in ruziziensis grass silage intercropped with corn, highlighting the importance of adopting integrated production systems. Estimates by NIRS presented high R2cv values (&gt;0.95), demonstrating the potential of this technology for routine analysis of tropical grass silages for CP, NDF, ADF, and ash.

Context The demand and production of renewable fuels are boosting the production of biofuels. Agricultural industries have been playing a role in the increase of ethanol production from corn and, consequently, their by-products. Dried distiller’s grain (DDG) is a by-product of corn ethanol and can be used as a source of protein and energy in the diet of feedlot lambs. Aims The objectives of this experiment were to evaluate the effects of including DDG in high-concentrate diets on performance, rumen morpho-histology, and carcass characteristics in feedlot lambs. Methods Forty-five Santa Inês × Dorper male lambs with an initial body weight of 21 ± 3.2 kg (mean ± s.d.) and 82 ± 12 days old (mean ± s.d.) were distributed in a randomised complete-block design (nine blocks and five treatments). The experimental diets contained 900 g/kg of concentrate and 100 g/kg of coastcross hay, and DDG was used in replacement of soybean meal and corn. Lambs were fed one of the following five diets for 112 days: control without DDG (0DDG), or diet with 150 (150DDG), 300 (300DDG), 450 (450DDG) and 600 (600DDG) g/kg DM of DDG. Key results The inclusion of DDG from 150 up to 600 g/kg DM in the diet of the lambs linearly decreased (P &lt; 0.01) dry-matter intake (DMI), net energy of maintenance intake, net energy of gain, average daily gain, final body weight and feed efficiency (P &lt; 0.01). The inclusion of DDG linearly decreased (P ≤ 0.04) hot carcass weight, cold carcass weight, hot carcass yield and cold carcass yield. For ruminal morpho-histology, there was a linear decrease in the area of papillae and absorptive surface area (P &lt; 0.01) Conclusions An increase in the DDG level from 150 to 600 g/kg DM in the diet of lambs negatively affected feedlot performance, with detrimental effects on carcass traits and the development of rumen papillae. The lambs showed low acceptance of DDG, even at the lowest level of dietary inclusion (150g/kg DM) as DMI was impaired. Implications DDG should be used with caution in diets for finishing lambs. Dietary inclusion of DDG up to 150 g/kg DM is recommended. Higher inclusions levels may significantly affect performance and carcass weight and yield.

Abstract The use of enzyme complex and the inclusion of corn ethanol co-products are strategies that can increase feed efficiency and carcass weight of feedlot beef cattle. Crossbred bulls (n = 389) were assigned to a randomized completed block design, according to their initial shrunk body weight (BW; 314 ± 40 kg; 10 pen/treatment). The treatment arrangement was a 2 × 3 factorial, with Factor 1 defined by the inclusion of corn dried bran/fiber plus distillers solubles (15 or 45% of DFS; FS Ouro from FS Bioenergy) and factor 2 defined by the increasing doses of multicarbohydrase complex (Rovabio Advance from Adisseo Company; 0, 0.75 or 1.0 g for every 10 kg of diet DM)). The diets contained 8.5% sugar cane bagasse, 44 or 73% ground flint corn, 15 or 45% DFS, 0.5 or 1.5% urea and 2% mineral mix plus monensin (30 ppm in the diet) with the respective enzyme complex doses. On d -1 and 122, individual BW were recorded after a 16-h of fasting (feed and water). The dry matter (DM) intake (DMI) was determined by the difference of feed offer and orts samples after dried at 105°C for 24 h to determine DM. The pen average daily gain (ADG) and DMI were used to calculate feed efficiency (ADG/DMI). On d 122, subcutaneous fat thickness (FT) and the rib eye area (REA) were obtained by means of an ultrasound image, and hot carcass weight (HCW) was obtained upon slaughter on the next day. Data were analyzed using the MIXED procedure of SAS. There was no interaction between the inclusion of DFS and enzyme doses for the variables evaluated (P &amp;gt; 0.05). The use of enzyme complex had no effect on cattle DMI, ADG and FE (P &amp;gt; 0.05). No effects of DFS levels were observed on daily DMI (P ≥ 0.45) or final BW (P ≥ 0.33). Nonetheless, cattle fed 45% DFS had greater ADG (1.37 vs. 1.28 kg; P = 0.02) and FE (153 vs. 145 g/ kg; P = 0.03) than cattle fed 15% DFS. There was no effect of the inclusion of DFS or the doses of the enzyme complex on the carcass parameters evaluated. In summary, including 45% DFS in finishing diets improved feedlot cattle performance compared with 15%. The use of the enzyme complex did not affect animal performance.

Increased demand for corn-based ethanol puts upward pressure on prices of corn and other commodities, such as soybeans, and possibly worsens their price volatility. The paper investigates the changes in agricultural commodities' standard deviation and beta sizes due to ethanol production in the US. Standard deviations and beta estimations are compared for the ethanol pre-expansion and expansion periods. The results indicate a high level of price volatility in the second period, which could be attributed to ethanol expansion.

Abstract This 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.

Abstract Existing corn ethanol biorefineries produce about 94% of the ethanol capacity in the USA and currently have surplus production capacity. Expanding feedstocks for existing facilities rather than building new dedicated facilities could provide significant benefits and cost savings. Grain sorghum is a feedstock with a similar composition to corn, which could be utilized at significant incorporation levels in existing facilities with minimal or no modifications but it is currently only used minimally. To understand the impact of grain sorghum incorporation better we studied mixed corn and grain sorghum fermentation at the laboratory scale and utilized the data generated to develop technical models for the individual grains and for a 50/50 mixture at 119 million kg per year (40 million gal per year). Detailed processing and economic comparisons were developed to determine the overall impact. The results showed significant feedstock savings ($8 million per year) potential for utilization of sorghum relative to corn. Ethanol production cost was reduced by $0.07 per kg of ethanol using sorghum relative to corn. Other potential impacts on coproduct composition and values were also determined and discussed.

This study aimed to determine the values of net energy (NE), digestible energy (DE) and metabolizable energy (ME) and digestibility coefficients of corn ethanol coproducts produced in Brazil and their effects on the nitrogen balance and blood parameters of pigs. Ten barrows were housed in metabolic study cages for total collection and fed a reference diet (RD) or 800 g/kg RD + 200 g/kg of a coproduct of corn ethanol. Distiller's dried grains with solubles (DDGS), corn bran with solubles (CBS), distiller's dried grains (DDG) and high-protein distiller's dried grain (HPDDG) were evaluated. The experimental design was randomized blocks with three repetitions per period, totaling six repetitions per diet. Diets containing the HPDDG had greater DE and ME than those containing CBS and DDGS and greater DE than those containing the DDG (p < 0.05). HPDDG, DDG, CBS and DDGS showed 4498, 3419, 3029 and 3335 kcal/kg DE; 4366, 3305, 2934 and 3214 kcal/kg ME; and 2515, 1938, 1649 and 1725 kcal/kg NE, respectively. Pigs fed diets containing HPDDG and CBS showed greater nitrogen retention efficiency than pigs fed DDGS (p < 0.05). Pigs fed diets containing HPDDG had higher blood urea levels than pigs fed CBS and RD, while triglyceride levels in animals that received the CBS diet were greater than those in animals that received all other diets. The HPDDG had the highest energy levels and the best digestibility coefficients. The chemical composition of coproducts influences the nitrogen balance and circulating levels of urea and triglycerides in pigs.

In very high gravity (VHG) fermentation, yeast cells are subjected to a multitude of challenging conditions, including the osmotic pressure exerted by the high sugar content of the wort and the stress factors associated with the high ethanol concentrations present at the end of the fermentation cycle. The response of this biological system to abiotic stresses may be enhanced through biochemical and physiological routes. Silica may play a significant role in regulating the cellular homeostasis of yeast. Alternatively, it is expected that this outcome may be achieved through biochemical responses from the effects of vitamins on yeast cells and the physiological yeast route changing by the culture medium aeration. The objective of this study was to investigate the effects of adding 500 mg L−1 of silica on corn ethanol wort medium and the possibility of supplementing the same wort with vitamins alongside aeration (0.2 v v−1 min−1) as an alternative resource to sustain the fermentation yield rather than adding silica in a fed-batch fermentation cycle with yeast recycling. Upon completion of the five fermentation cycles, yeast samples subjected to the treatment with the addition of silica exhibited a 3.1% higher fermentation yield in comparison to the results observed in the vitamins plus aeration medium bath. Even though greater biomass production (19.1 g L−1) was observed through aerobic yeast behavior in vitaminized supplemented corn medium, the provided silica had a more beneficial effect on yeast stress relief for very high gravity fermentation in a corn hydrolyzed wort with cell recycling.