Ethanol Production Facilities Research Articles

Production of a Bacteriocin Like Protein PEG 446 from Clostridium tyrobutyricum NRRL B-67062.

Clostridium tyrobutyricum strain NRRL B-67062 was previously isolated from an ethanol production facility and shown to produce high yields of butyric acid. In addition, the cell-free supernatant of the fermentation broth from NRRL B-67062 contained antibacterial activity against certain Gram-positive bacteria. To determine the source of this antibacterial activity, we report the genome and genome mining of this strain. The complete genome of NRRL B-67062 showed one circular chromosome of 3,242,608 nucleotides, 3114 predicted coding sequences, 79 RNA genes, and a G+C content of 31.0%. Analyses of the genome data for genes potentially associated with antimicrobial features were sought after by using BAGEL-4 and anti-SMASH databases. Among the leads, a polypeptide of 66 amino acids (PEG 446) contains the DUF4177 domain, which is an uncharacterized highly conserved domain (pfam13783). The cloning and expression of the peg446 gene in Escherichia coli and Bacillus subtilis confirmed the antibacterial property against Lactococcus lactis LM 0230, Limosilactobacillus fermentum 0315-25, and Listeria innocua NRRL B-33088 by gel overlay and well diffusion assays. Molecular modeling suggested that PEG 446 contains one alpha-helix and three anti-parallel short beta-sheets. These results will aid further functional studies and facilitate simultaneously fermentative production of both butyric acid and a putative bacteriocin from agricultural waste and lignocellulosic biomass materials.

Assessing feasible H2–CO2 sources in the US as Feedstocks for Sustainable Aviation Fuel Precursors: Acetic Acid and Ethanol Production via Hydrogenotrophic Pathways

The environmental impact of carbon dioxide emissions is significant, and research is focused on mitigating these emissions and developing eco-friendly technologies in line with green chemistry principles. Waste-to-energy technologies play a crucial role in converting waste into renewable energy and valuable biofuels and bioproducts. This study specifically explores the utilization of waste gas emissions, particularly carbon dioxide, from various sources in the United States for the production of sustainable aviation fuel (SAF) precursors, such as ethanol and acetic acid. The study categorizes and quantifies the volumes of carbon dioxide emissions into three types: non-biogenic, biogenic, and biogenic emissions from ethanol production facilities. Stoichiometric calculations are applied to compare the amounts of carbon dioxide from each category with the available hydrogen production capacity, determining if sufficient hydrogen is present for converting carbon dioxide into SAF precursors. The study reveals two key findings. Firstly, there is a significant reserve of carbon dioxide, approximately 1648 million metric tons per year (MMTy), combining all three categories, which would require a substantial increase of approximately 35–40 times in the existing hydrogen production capacity of 4.988 MMTy. This increased hydrogen production has the potential to yield approximately 1067.82 MMTy of acetic acid and 189.19 MMTy of ethanol annually. Secondly, upon analyzing the quality and application of the three sources of carbon dioxide with the currently available hydrogen production capacity, it is found that biogenic carbon dioxide from ethanol plants is the most suitable choice for immediate production of SAF precursors. This would theoretically result in an annual production of 1.36 MMTy of ethanol and 1.772 MMTy of acetic acid. The other two sources of carbon dioxide can be considered potential reserves for future utilization when additional hydrogen production facilities are established.The study provides a foundation for assessing the aggregation potential required for acetic acid and ethanol production. By optimizing the use of waste gases as raw materials, the study not only enables the production of SAF precursors but also contributes to the passive reduction of greenhouse gas emissions.

Application of emerging monitoring techniques at the Illinois Basin – Decatur Project

The Illinois Basin – Decatur Project is a large-scale carbon capture and storage demonstration project located in Decatur, Illinois, USA. In this project, one million metric tons of carbon dioxide (CO2) was captured from an ethanol production facility and successfully injected into a deep saline reservoir over a period of three years. The scale of this project presented an opportunity to explore emerging technologies for effective long-term monitoring of the carbon capture and storage site. This research documents the application of three emerging monitoring techniques: (1) a prototype “open-path” sensor, a method of continuously monitoring atmospheric CO2 by applying tunable diode laser absorption spectroscopy to provide a warning system for personnel safety along pipelines and at wellheads; (2) the Greenhouse Gas Laser Imaging Tomography Experiment (GreenLITE), an automated system for measuring two-dimensional spatial distribution of atmospheric CO2 concentrations; and (3) periodic aerial imagery, a method of documenting surface-vegetation dynamics to detect vegetative responses to CO2 leaks. The goal of this work was to assess the advantages and limitations of these monitoring techniques and quantify their reliability over an extended deployment at an active industrial site. These results will aid in determining viability of long-term monitoring on a commercial scale.

Virginiamycin Thermal Degradation Kinetics in a Model Matrix Simulating Distillation Conditions within a Commercial Fuel Ethanol Production Facility

The current knowledge of virginiamycin (VM) degradation kinetics at processing conditions observed in commercial ethanol production facilities is very limited. This knowledge is critical for assessing the feed and animal-derived food safety risk of the presence of VM residues in dried distillers grains with solubles (DDGS). A bioassay method was optimized to quantify the VM residues in a matrix sample obtained from distillation at an ethanol production facility. There were no significant differences on the VM degradation kinetics among the pH values of the distillation matrix sample used in the DDGS production (P=0.98). Increasing the distillation temperature enhanced the reduction of VM (P<0.01) reaching 70% degradation at 95°C. The log-linear model was able to characterize the VM degradation kinetics with D-values ranging from 19.4 to 43.3min at 70–95°C. The M1 subunit was less heat-resistant with D-values ranging from 10.4 to 23.6min. Distillation temperature conditions commonly used during the DDGS production process significantly degrades VM providing vital information for ethanol and food animal producers on the potential risk of the presence of antimicrobial residues in the final DDGS product.

Advanced Simulation and Analysis of MIMO Dead Time Compensator and Predictive Controller for Ethanol Distillation Process

Abstract This paper analyses advanced control strategies in an ethanol production facility. A Matlab computing platform integrated with Aspen Hysys was developed to simulate industry practice. Two types of advanced control system were used in this study: a Model Predictive Control and a Dead Time Compensator. In particular, an Infinite Horizon Predictive Controller (IHMPC) and Filtered Smith Predictor (FSP) controller were designed to ensure ethanol production into a desired quality range under feed variations as disturbances. Performance indexes and computational processing time were used to evaluate the control systems. This work offers different and satisfactory solutions for several application scenarios, taking in account the main characteristics of each controller.

Modeling the Feasibility of Using Solar Thermal Systems for Meeting the Heating Requirements at Corn Ethanol Production Facilities

While ethanol use as a vehicle fuel has been promoted as a renewable alternative to fossil fuels, current production methods of ethanol from corn feedstock rely heavily on the combustion of nonrenewable fuels such as natural gas. Solar thermal systems can provide a renewable energy source for supplying some of the heat required ethanol production. In this paper, a model to analyze the feasibility of using solar thermal energy to reduce natural gas consumption in ethanol production is described and applied. Sites of current ethanol production facilities are used to provide a realistic analysis of the economic feasibility of using solar thermal energy in the ethanol production process. The results show that it is not reasonable to expect to replace all of the natural gas consumption in the heating processes in ethanol production but that application of solar thermal energy can be applied to a specific subsystem such as the preheating of boiler makeup water. Profitability of systems for replacing a fraction of the natural gas is analyzed. It is found that both location and local natural gas prices are important in determining whether to pursue such a project and that solar thermal systems should have long-term profitability.

What Prospects for the Brazilian Ethanol Sector?

SummaryBrazilian ethanol is derived from sugarcane and is mostly used domestically as a transportation fuel either pure or mixed with gasoline. Brazilians will fill their cars with pure ethanol when its pump price in energy equivalent is lower than the price of gasohol, the mandatory mixture of ethanol and gasoline. Over the last decade, Brazilian ethanol companies have used debt financing to meet the expected increase in domestic and international ethanol demand, which did not fully realise. With the current economic crisis, the ethanol sector, the second largest worldwide, is restructuring and seeking additional earning opportunities; co‐generation and valorisation of by‐products are likely to develop. Political commitments towards the ethanol sector through mandatory blending obligations or the fuel taxation system are strong. Domestic ethanol demand should thus remain sustained in the medium term. In addition, sugarcane‐based ethanol has the best GHG emission reduction profile of all biofuels available on a large scale. Advanced ethanol based on sugarcane derived biomass has the potential to perform even better; here Brazil has a major role to play in the future. However massive flows of investments are needed to develop competitive and innovative large‐scale advanced ethanol production facilities in the country.

Sorghum and Switchgrass as Biofuel Feedstocks on Marginal Lands in Northern China

To avoid food versus fuel conflicts in China, the production of bioenergy crops requires the evaluation of marginal lands under arid and semiarid conditions. We conducted field experiments with sorghum (Sorghum bicolor (L.) Moench) and switchgrass (Panicum virgatum L.) in Northern China. The biomass yield and nutrient (N, P, and K) accumulation of sorghum (leaves and stalks) and switchgrass (aboveground portion) were examined in 2012 and 2013. The soil organic carbon (SOC) content at depths of 0–30 cm was quantified at sorghum, switchgrass, and native grassland sites. The aboveground biomass yield of sorghum averaged 13.9 t ha−1 (14.2 and 13.6 t ha−1 in 2012 and 2013, respectively), while the switchgrass yield had a higher variability (14.8 versus 8.1 t ha−1 in 2012 and 2013, respectively) and averaged 11.5 t ha−1. The removals of N, P, and K averaged 56, 10, and 160 kg ha−1, respectively, for sorghum and 41, 11, and 89 kg ha−1, respectively, for switchgrass. To attain maximum biomass yield with minimum nutrient removal and the lowest transportation costs (due to the moisture content), the switchgrass harvest should be delayed until approximately 160 days after regrowth (DAR) in this region, whereas sorghum, which matures earlier, can be harvested as early as 120 days after sowing (DAS). Earlier harvests would increase the flexibility for large-scale ethanol production facilities. The SOC content within the 0–15-cm layer averaged 15.8 and 11.6 g C kg−1 before and 3 years after the establishment of the switchgrass culture, respectively, although the SOC increased with the culture age. In contrast, the SOC content of the 15–30-cm layer did not differ between the adjacent native grassland and the switchgrass planting. Under sorghum, the SOC content was reduced although it did not differ significantly from that of the native grassland at a significance level of p < 0.05. We conclude that high biomass yields can be obtained from the two crops under natural rainfall in the arid and semiarid conditions of Northern China. To address nutrient removal and SOC reduction, the leaves of sorghum should be returned to the field to increase the input of organic materials into the soil and reduce nutrient removal, which enhances soil fertility and sustainable production.

Cost minimization of supplying biomass for ethanol biorefineries

A major hurdle facing commercial biofuel production is the cost of producing the feedstock. Since biofuel feedstock is bulky in nature, a large proportion of cost needed to be allocated for harvesting and transportation of feedstock. Economic viability of ethanol production from cellulosic feedstock depends in part of the cost to produce, harvest and deliver feedstock to the ethanol production facilities. A well-developed harvesting and transportation system does not exist for most feedstock. Hence to determine accurate estimation of the harvest, transportation and storage costs is important in ethanol production. The objectives of the study are to determine the optimal harvesting unit for ethanol biorefinery and estimate harvesting, storage and transportation costs of switchgrass under various harvesting schedules. A biorefinery with the annual capacity of processing 4.16 million gallons of ethanol was considered. Based on average dry matter yield, total production area needed for annual harvesting was estimated. The harvesting units needed for the continuous harvest and supply of biomass were estimated based on information on the capacity of machineries etc. Accordingly various costs associated with operating and maintaining harvesting unit were estimated. Transportation units needed were estimated for continuous supply of feedstock to the refinery and the associated costs were calculated.The number of machinery needed for a harvesting unit for the 90 day harvesting schedule are the most while year round harvesting schedules needs lesser number of machinery for a harvesting unit. Harvesting switchgrass in 90 day schedule is the most expensive scenario with all harvesting, hauling and storage costs added together. Year round harvesting schedule occurs as the least costly scenario. Sensitivity analysis shows the positive trend for harvesting and hauling costs to biomass yield, ethanol conversion technology, distance and decreasing trend for the range of truck speed considered. The results generated in this study will be useful in designing optimal harvest schedule of biomass for ethanol biorefinery.

The implications of the US renewable fuel standard programme for farm structure

ABSTRACTWe investigate the impact of the 2005 Renewable Fuel Standard (RFS) on farm structure, particularly farm size. We rely on the salience of a new ethanol plant in a farmers’ local neighbourhood to identify the impact of the RFS mandate on these spatially advantaged farms. To control for the nonrandom selection of ethanol production facilities, we utilize a propensity score matching estimator, and to remove impact of farm-level or market shifting unobservables resulting from shifts in commodity prices we employ a difference-in-difference (DD) matching approach. We estimate the treatment effect of an ethanol production facility on farm size prior to the RFS mandate and after the RFS programme. The effect of the RFS policy on farm size is obtained as the difference between these two DD matching estimators. Overall, our results suggest that the RFS programme raised the probability of farm size increase by roughly 12–18%, on average, for farms located within a 30-mile radius of new ethanol plants. In addition, the programme contributed to a net increase in farm size of 25–32%, on average, for those spatially advantaged farms.

N2 gas is an effective fertilizer for bioethanol production by Zymomonas mobilis

A nascent cellulosic ethanol industry is struggling to become cost-competitive against corn ethanol and gasoline. Millions of dollars are spent on nitrogen supplements to make up for the low nitrogen content of the cellulosic feedstock. Here we show for the first time to our knowledge that the ethanol-producing bacterium, Zymomonas mobilis, can use N2 gas in lieu of traditional nitrogen supplements. Despite being an electron-intensive process, N2 fixation by Z. mobilis did not divert electrons away from ethanol production, as the ethanol yield was greater than 97% of the theoretical maximum. In a defined medium, Z. mobilis produced ethanol 50% faster per cell and generated half the unwanted biomass when supplied N2 instead of ammonium. In a cellulosic feedstock-derived medium, Z. mobilis achieved a similar cell density and a slightly higher ethanol yield when supplied N2 instead of the industrial nitrogen supplement, corn steep liquor. We estimate that N2-utilizing Z. mobilis could save a cellulosic ethanol production facility more than $1 million/y.

Proteomic analyses of ethanol tolerance inLactobacillus buchneriNRRL B-30929

The Lactobacillus buchneri NRRL B-30929 strain, isolated from a fuel ethanol (EtOH) production facility, exhibits high tolerance to environmental EtOH concentrations. This study aimed to identify proteins produced by B-30929 in response to environmental EtOH. Cellular proteins expressed by B-30929 growing in media with 10 versus 0% EtOH were compared by 2DE, followed by in-gel digestion and MALDI-MS analyses. Twenty EtOH responsive proteins were identified. These include a proline-specific peptidase (Lbuc_1852); a membrane protein (Lbuc_0921), two general stress-related proteins including a 10 kDa chaperonin (GroESL Lbuc_1359) and a 29 kDa member of the HK 97 family (Lbuc_1523); metabolic enzymes involving redox potential balances (Lbuc_2051 and Lbuc_0522) and carbohydrate fermentation (Lbuc_1319 and Lbuc_2157); nitrogen, amino acid, and fatty acid metabolism proteins (Lbuc_1994, Lbuc_0446, Lbuc_0858, Lbuc_0707, and Lbuc_0787). These changes suggested B-30929 cells respond to EtOH by degradation of available proteins and fatty acids and increased production of specific enzymes and molecular chaperons. These results can be used to guide genetic modifications to increase EtOH tolerance in industrial biocatalysts. The data have been deposited to World-2DPAGE (http://world-2dpage.expasy.org/repository/0068/; username liu, password 1h8d6Mg1).

Traditional Fermentation and Distillation of Raffia Palm Sap for the Production of Bioethanol in Bayelsa State, Nigeria

The production of alcoholic beverages from the sap of raffia palm, Raphia hookeri, has continued for decades in West Africa, but the detailed processes had never been documented before. The objective of this study is to document the traditional process of ethanol production, with the aim of scaling up the process for the production of fuel ethanol. Ten smallholder ethanol production facilities were randomly selected, and triplicate samples of the process intermediates were collected and analysed, including fermented palm sap, first and second distillate, first and second stillage. Results show that the percentage of ethanol was significantly different (P&lt;0.05) among the different intermediates. The highest ethanol presence was recorded in the second distillate (39-61.5%), followed by the first distillate (18.83-39%), then the first stillage (5.80-10.20%), the palm sap (10.50-15.30%) and finally the second stillage (3.40-5.80%).Yeast population, pH, sugar, specific gravity and electrical conductivity differed significantly among the various sites and intermediates. Wood (105-155kg) was used as fuel to boil 280-480L of fermented palm sap producing 20L of 39-61.5% ethanol. The smallholder processors are however challenged by the poor distillation apparatus and the lack of ethanol dehydration facilities. The study concludes by recommending the modification of the Nigerian Biofuel Policy (2007) to allow the use of hydrous ethanol in automobiles and low concentration ethanol for household cooking.

Vegetable Spirits and Energy Policy

This study investigates the extent to which the 2005 Energy Policy Act, specifically the ethanol mandate, contributed to the rise in farmland values. We use the location of new ethanol plants to identify the capitalization effect of the mandate by these spatially advantaged operations. We use a difference‐in‐difference propensity score matching estimator to control for the non‐random selection of ethanol production facilities. The empirical strategy uses farmland parcel values from the 2001–7 June Agriculture Survey. We find that new ethanol facilities had no effect on nearby farmland values prior to the mandate but had statistically significant effects after the policy.

The Implications of the U.S. Renewable Fuel Standard Program for Farm Structure

This study investigates the extent to which the 2005 Renewable Fuel Standard (RFS) has affected farm structure, in particular farm size. Our empirical strategy relies on the opening of an ethanol plant in a farmer’s local neighborhood. We identify the effect of the RFS on the size of farms located in the vicinity of new ethanol plants. Using a unique farm-level panel dataset from the June Agricultural Survey (JAS), the empirical estimation employs two difference-in-difference (DD) propensity score matching models, one prior to the RFS mandate and one incorporating the RFS program, to estimate an average treatment effect on farm size of an ethanol production facility. We then measure the effect of the RFS program on farmland structure as the difference between these two DD matching estimators. Overall, our results suggest that the RFS program raised the probability of farm size increase by roughly 12 to 18%, on average, for farms located within a 30-mile radius of new ethanol plants. In addition, the program contributed to a net increase in farm size of 25 to 32%, on average, for those spatially advantaged farms.

'Vegetable Spirits' and Energy Policy

This study investigates the extent to which the 2005 Energy Policy Act with its embedded Renewable Fuel Standard (RFS) program contributed to the rise in farmland values since 2004. We rely on the salience of a new ethanol plant in a farmers’ local neighborhood to identify the capitalization effect of the RFS mandate on these spatially advantaged farms. We identify the mean effect of the RFS on farmland values as the difference in the land-value capitalization of new ethanol plants before and after the RFS program. We use a propensity score matching estimator to control for the non-random selection of ethanol production facilities. To remove the impact of other possible unobserved shocks at the farm or market level resulting from shifts in commodity prices, we employ a difference-in-difference matching approach. The empirical strategy exploits a temporal and spatially detailed dataset that combines farmland parcel value estimates from the USDA’s June Agriculture Survey (JAS) for the years 2001-2007, location and construction timing of all U.S. ethanol plants, measures of urban influence, and detailed soil productivity data. We find that the construction of new ethanol facilities had no effect on nearby farmland values prior to the RFS legislation but had statistically significant effects on nearby farmland values after the RFS law passed. We estimate that the net capitalization effect of the RFS program on nearby farmland ranged from 15% to 28% in 2006. Our findings suggest that the RFS created expectations of higher returns to agriculture in excess of the returns derived from higher commodity prices. The findings are also in line with previous empirical evidence on the capitalization of agricultural policies into farmland values.

Microbial contamination of fuel ethanol fermentations

Microbial contamination is a pervasive problem in any ethanol fermentation system. These infections can at minimum affect the efficiency of the fermentation and at their worse lead to stuck fermentations causing plants to shut down for cleaning before beginning anew. These delays can result in costly loss of time as well as lead to an increased cost of the final product. Lactic acid bacteria (LAB) are the most common bacterial contaminants found in ethanol production facilities and have been linked to decreased ethanol production during fermentation. Lactobacillus sp. generally predominant as these bacteria are well adapted for survival under high ethanol, low pH and low oxygen conditions found during fermentation. It has been generally accepted that lactobacilli cause inhibition of Saccharomyces sp. and limit ethanol production through two basic methods; either production of lactic and acetic acids or through competition for nutrients. However, a number of researchers have demonstrated that these mechanisms may not completely account for the amount of loss observed and have suggested other means by which bacteria can inhibit yeast growth and ethanol production. While LAB are the primary contaminates of concern in industrial ethanol fermentations, wild yeast may also affect the productivity of these fermentations. Though many yeast species have the ability to thrive in a fermentation environment, Dekkera bruxellensis has been repeatedly targeted and cited as one of the main contaminant yeasts in ethanol production. Though widely studied for its detrimental effects on wine, the specific species-species interactions between D. bruxellensis and S. cerevisiae are still poorly understood.

Renewable fuels: Policy effectiveness and project risk

This paper examines the impact of government policy on the risk profile of a small ethanol production facility. We derive four key results from a simulation model. First, we show that commodity price risk may discourage investment in a project, despite a positive expected rate of return. Second, we show that political uncertainty may have significant impacts on the risk profile of a project. Next, we show that using only production subsidies to attract investors is expensive, since the financial assistance is paid regardless of whether the plant is operating under positive or negative financial conditions. Finally, we show that a capital grant provides a valuable complement to a subsidy, because the grant reduces the amount of value investors must put at risk, and increases their leverage thereby enhancing returns, while the subsidy mitigates commodity price risk. Our results show that compared to a subsidy-only approach, a grant and subsidy combination provides an investment environment with similar downside protection and expected returns for less than 60% of the cost. Further, we show that the two policy tools combined yield a superior investment environment to that created by an equivalent or greater total investment deployed entirely in either of the policy tools without the other.

Analysis of Federal and State Policies and Environmental Issues for Bioethanol Production Facilities

The purpose of this work was to investigate incentives and barriers to fuel ethanol production from biomass in the U.S. during the past decade (2000-2010). In particular, we examine the results of policies and economic conditions during this period by way of cellulosic ethanol activity in four selected states with the potential to produce different types of feedstocks (i.e., sugar, starch, and cellulosic crops) for ethanol production (Florida, California, Hawaii, and Iowa). Two of the four states, Iowa and California, currently have commercial ethanol production facilities in operation using corn feedstocks. While several companies have proposed commercial scale facilities in Florida and Hawaii, none are operating to date. Federal and state policies and incentives, potential for feedstock production and conversion to ethanol and associated potential environmental impacts, and environmental regulatory conditions among the states were investigated. Additionally, an analysis of proposed and operational ethanol production facilities provided evidence that a combination of these policies and incentives along with the ability to address environmental issues and regulatory environment and positive economic conditions all impact ethanol production. The 2000-2010 decade saw the rise of the promise of cellulosic ethanol. Federal and state policies were enacted to increase ethanol production. Since the initial push for development, expansion of cellulosic ethanol production has not happened as quickly as predicted. Government and private funding supported the development of ethanol production facilities, which peaked and then declined by the end of the decade. Although there are technical issues that remain to be solved to more efficiently convert cellulosic material to ethanol while reducing environmental impacts, the largest barriers to increasing ethanol production appear to be related to government policies, economics, and logistical issues. The numerous federal and state policies do not effectively give investors confidence to commit to the construction and long-term operation of facilities under current economic conditions. Additional changes in policy and breakthroughs in technology and logistics will be required to address these hurdles to increases in ethanol production in the U.S. in the next decade.

Rapid evaluation of the antibiotic susceptibility of fuel ethanol contaminant biofilms

Bacterial contaminants from commercial fuel ethanol production facilities were previously shown to form biofilms as mixed cultures under laboratory conditions. In this study, a rapid assay was developed to simultaneously compare isolates for their ability to form biofilms as pure cultures. A total of 10 strains were isolated from a dry-grind fuel ethanol plant that routinely doses with virginiamycin. These were identified by sequence analysis as six strains of Lactobacillus fermentum, two strains of L. johnsonii, and one strain each of L. mucosae and L. amylovorus. Isolates exhibited a range of susceptibility to virginiamycin in a planktonic assay, with MIC's (minimum inhibitory concentration) of ≤0.5-16 μg/ml. Even though all strains were isolated from a mixed culture biofilm, they varied greatly in their ability to form biofilms as pure cultures. Surprisingly, growth as biofilms did not appear to provide resistance to virginiamycin, even if biofilms were grown for 144 h prior to antibiotic challenge.