Estimating geographic origins of corn and soybean biomass for biofuel production: A detailed dataset

Sustainable fuel initiatives in the United States such as the Environmental Protection Agency's Renewable Fuel Standard and the Department of Energy's Sustainable Aviation Fuel Grand Challenge have increased the production of corn ethanol and soybean biodiesel. However, the lack of precise information regarding biomass sourcing at a localized level has hindered accurate understanding of both biofuel costs and environmental impact of these production pathways. By harnessing the power of geospatial analysis and leveraging United States Department of Agriculture (USDA) crop census data, this dataset fills this critical knowledge gap. This dataset offers a novel estimation of geospatial biomass sourcing for biofuel production in the United States by synthesizing 2017 USDA crop census data, biorefinery data from the United States Energy Information Administration, and publicly available information about biomass sourcing for biofuel production. This dataset provides a detailed understanding of biomass use for first generation biofuel production, enabling stakeholders to make informed decisions about resource allocation, investment strategies, and infrastructure development. Furthermore, the county-level granularity of the dataset allows for increased fidelity in the techno-economic assessments and life-cycle analyses of first-generation biofuels in the United States.

Enzymatic complex for broilers fed on a diet containing different levels of Distiller Dried Grains with Solubles

The objective of this research was to evaluate the effect of the inclusion of an enzyme complex (carbohydrases, proteases and phytase) in diets formulated with DDGS inclusion levels (0 to 30%) in parameters of performance, nutrient digestibility and serum biochemical profile of broiler chickens from 1 to 42 days old. The inclusion of DDGS impaired the performance characteristics in all phases, but broilers feeding with diets containing up to 8% DDGS improves the percentage carcass. Addition of the enzyme complex improved feed conversion by 3.6% and percentage of breast by 1.6%. At 42 days of age, there was a linear decreasing effect of the addition of DDGS in the diets on the relative weight of PV + gizzard (proventriculum + gizzard). Diets without enzyme addition decreased IDCDM, IDCCP and IDCNDF. Inclusion of DDGS up to 8 % results in maximum percentage carcass. The use of exogenous enzymes improves FCR (feed conversion ratio) in the pre-initial phase.

An integrative approach enables high bioresource utilization and bioethanol production from whole stillage

Bioethanol is a major biofuel in industry and mainly produced from corn starch with the dry-mill process. However, one of the remaining challenges is how to economically and efficiently exploit the wasted co-products to further improve ethanol production and generate more valuable chemicals. Here, an integrative approach was developed to efficiently utilize the waste cake for ethanol production, accompanied by protein extraction for feed additives. A high-quality protein feed was produced by the ethanol-alkali extraction method (extraction rate up to 46.91%). Notably, by applying two-step chemoenzymatic strategy, the supernatant and solid recycling yield up to 4.1-, 3.8-, and 154-fold improvements of ethanol, glucose, and xylose production, respectively, comparing to non-pretreatment. Moreover, mass balance analysis found this approach significantly contributed 1.74-4.42% (5.96-15.11 kg/ton dry corn) increase of total ethanol production. The gained knowledge about process design holds the potential transferability for other sustainable biowaste management and bioethanol industry.

Optimization of dilute sulfuric acid, aqueous ammonia, and steam explosion as the pretreatments steps for distillers' dried grains with solubles as a potential fermentation feedstock

Distillers' dried grains with solubles (DDGS) is the by-product of bioethanol production from starch-rich grains through dry-mill fermentation. In this study, dilute sulfuric acid hydrolysis, aqueous ammonia, and steam explosion as the pre-treatment methods were optimized. The central composite response surface methodology (RSM) design was used for optimization of dilute acid pretreatment, aqueous ammonia pretreatment. The steam explosion trials were evaluated. The results show that the dilute acid pretreatment at 121 °C is the most effective way of obtaining simple fermentable sugars (0.382 g/g DDGS). The levels of furfural and HMF was also 5.2 mg/g DDGS) and 1.6 mg/g DDGS, respectively, in the dilute sulfuric acid pretreated DDGS. On the other hand, maximum sugar yield for ammonia pretreatment was 0.129 g/g DDGS and 0.055 g/g DDGS for the steam pretreatment, while no significant amounts of furfural and HMF were observed for these two pretreatment methods.

Process integration for ethanol production from corn and corn stover as mixed substrates

This work investigated all possible process integration strategies for ethanol production from corn and dilute acid pretreated corn stover (CS) as mixed substrates. Three corn to pretreated CS ratios (20%:10%, 10%:20% and 5%:25%) were examined. When the ratio of corn to pretreated CS was 20%:10%, the process integration strategy that mixed corn with CS hydrolysate for liquefaction followed by SSF resulted in the highest ethanol titer of 99.3 g/L. Mixing liquefied corn with pretreated CS for hydrolysis/saccharification followed by fermentation was the best strategy for the other two ratios. The strategy of mixing liquefied corn with pretreated CS for 6 h hydrolysis followed by fermentation showed the highest productivity for all the tested ratios.

Bioprocessing and technoeconomic feasibility analysis of simultaneous production of d-psicose and ethanol using engineered yeast strain KAM-2GD

The objective of this study was to analyze the processing and technoeconomic feasibility of coproduction of d-psicose and ethanol in a modified dry grind ethanol process. The yeast strain was constructed by expressing d-psicose 3-epimerases (DPE) in Sachharomyces cerevisiae. The strain was capable of converting d-fructose to d-psicose at 55 °C with a conversion efficiency of 26.6%. A comprehensive process model for modified dry grind ethanol plant with 396,000 MT/yr corn processing capacity was developed using SuperPro Designer. Predicted ethanol and d-psicose yields were 390.4 L and 75.3 kg per MT of corn, with total annual production of 154.6 million L and 29,835 MT respectively. The capital investment for the plant was estimated as 150.3 million USD with total operating cost of 85.2 million USD/yr. The unit production cost and minimum selling price of d-psicose with an internal rate of return of 15% were calculated as $0.43/kg and $1.29/kg respectively.

Influence of corn oil recovery on life-cycle greenhouse gas emissions of corn ethanol and corn oil biodiesel

BACKGROUND

Corn oil recovery and conversion to biodiesel has been widely adopted at corn ethanol plants recently. The US EPA has projected 2.6 billion liters of biodiesel will be produced from corn oil in 2022. Corn oil biodiesel may qualify for federal renewable identification number (RIN) credits under the Renewable Fuel Standard, as well as for low greenhouse gas (GHG) emission intensity credits under California's Low Carbon Fuel Standard. Because multiple products [ethanol, biodiesel, and distiller's grain with solubles (DGS)] are produced from one feedstock (corn), however, a careful co-product treatment approach is required to accurately estimate GHG intensities of both ethanol and corn oil biodiesel and to avoid double counting of benefits associated with corn oil biodiesel production.

RESULTS

This study develops four co-product treatment methods: (1) displacement, (2) marginal, (3) hybrid allocation, and (4) process-level energy allocation. Life-cycle GHG emissions for corn oil biodiesel were more sensitive to the choice of co-product allocation method because significantly less corn oil biodiesel is produced than corn ethanol at a dry mill. Corn ethanol life-cycle GHG emissions with the displacement, marginal, and hybrid allocation approaches are similar (61, 62, and 59 g CO2e/MJ, respectively). Although corn ethanol and DGS share upstream farming and conversion burdens in both the hybrid and process-level energy allocation methods, DGS bears a higher burden in the latter because it has lower energy content per selling price as compared to corn ethanol. As a result, with the process-level allocation approach, ethanol's life-cycle GHG emissions are lower at 46 g CO2e/MJ. Corn oil biodiesel life-cycle GHG emissions from the marginal, hybrid allocation, and process-level energy allocation methods were 14, 59, and 45 g CO2e/MJ, respectively. Sensitivity analyses were conducted to investigate the influence corn oil yield, soy biodiesel, and defatted DGS displacement credits, and energy consumption for corn oil production and corn oil biodiesel production.

CONCLUSIONS

This study's results demonstrate that co-product treatment methodology strongly influences corn oil biodiesel life-cycle GHG emissions and can affect how this fuel is treated under the Renewable Fuel and Low Carbon Fuel Standards.

Land usage attributed to corn ethanol production in the United States: sensitivity to technological advances in corn grain yield, ethanol conversion, and co-product utilization

BACKGROUND

Although the system for producing yellow corn grain is well established in the US, its role among other biofeedstock alternatives to petroleum-based energy sources has to be balanced with its predominant purpose for food and feed as well as economics, land use, and environmental stewardship. We model land usage attributed to corn ethanol production in the US to evaluate the effects of anticipated technological change in corn grain production, ethanol processing, and livestock feeding through a multi-disciplinary approach. Seven scenarios are evaluated: four considering the impact of technological advances on corn grain production, two focused on improved efficiencies in ethanol processing, and one reflecting greater use of ethanol co-products (that is, distillers dried grains with solubles) in diets for dairy cattle, pigs, and poultry. For each scenario, land area attributed to corn ethanol production is estimated for three time horizons: 2011 (current), the time period at which the 15 billion gallon cap for corn ethanol as per the Renewable Fuel Standard is achieved, and 2026 (15 years out).

RESULTS

Although 40.5% of corn grain was channeled to ethanol processing in 2011, only 25% of US corn acreage was attributable to ethanol when accounting for feed co-product utilization. By 2026, land area attributed to corn ethanol production is reduced to 11% to 19% depending on the corn grain yield level associated with the four corn production scenarios, considering oil replacement associated with the soybean meal substituted in livestock diets with distillers dried grains with solubles. Efficiencies in ethanol processing, although producing more ethanol per bushel of processed corn, result in less co-products and therefore less offset of corn acreage. Shifting the use of distillers dried grains with solubles in feed to dairy cattle, pigs, and poultry substantially reduces land area attributed to corn ethanol production. However, because distillers dried grains with solubles substitutes at a higher rate for soybean meal, oil replacement requirements intensify and positively feedback to elevate estimates of land usage.

CONCLUSIONS

Accounting for anticipated technological changes in the corn ethanol system is important for understanding the associated land base ascribed, and may aid in calibrating parameters for land use models in biofuel life-cycle analyses.