The Effect of Biomass Densification on Structural Sugar Release and Yield in Biofuel Feedstock and Feedstock Blends

In this work, we examined the behavior of feedstock blends and the effect of a specific feedstock densification strategy (pelleting) on the release and yield of structural carbohydrates in a laboratory-scale dilute acid pretreatment (PT) and enzymatic hydrolysis (EH) assay. We report overall carbohydrate release and yield from the two-stage PT-EH assay for five single feedstocks (two corn stovers, miscanthus, switchgrass, and hybrid poplar) and three feedstock blends (corn stover-switchgrass, corn stover-switchgrass-miscanthus, and corn stover-switchgrass-hybrid poplar). We first examined the experimental results over time to establish the robustness of the PT-EH assay, which limits the precision of the experimental results. The use of two different control samples in the assay enabled us to identify (and correct for) a small bias in the EH portion of the combined assay for some runs. We then examined the effect of variable pretreatment reaction conditions (residence time, acid loading, and reactor temperature) on the conversion of a single feedstock (single-pass corn stover, CS-SP) in order to establish the range of pretreatment reaction conditions likely to provide optimal conversion data. Finally, we applied the assay to the 16 materials (8 feedstocks in 2 formats, loose and pelleted) over a more limited range of pretreatment experimental conditions. The four herbaceous feedstocks behaved similarly, while the hybrid poplar feedstock required higher pretreatment temperatures for optimal results. As expected, the yield data for three blended feedstocks were the average of the yield data for the individual feedstocks. The pelleting process appears to provide a slightly positive effect on overall total sugar yield.     

Agent-Based Analysis of Biomass Feedstock Production Dynamics

The success of the bioenergy sector based on lignocellulosic feedstock will require a sustainable and resilient transition from the current agricultural system focused on food crops to one also producing energy crops. The dynamics of this transition are not well understood. It will be driven significantly by the collective participation, behavior, and interaction of various stakeholders such as farmers within the production system. The objective of this work is to study the system dynamics through the development and application of an agent-based model using the theory of complex adaptive systems. Farmers and biorefinery, two key stakeholders in the system, are modeled as independent agents. The decision making of each agent as well as its interaction with other agents is modeled using a set of rules reflecting the economic, social, and personal attributes of the agent. These rules and model parameters are adapted from literature. Regulatory mechanisms such as Biomass Crop Assistance Program are embedded in the decision-making process. The model is then used to simulate the production of Miscanthus as an energy crop in Illinois. Particular focus has been given on understanding the dynamics of Miscanthus adaptation as an agricultural crop and its impact on biorefinery capacity and contractual agreements. Results showed that only 60% of the maximum regional production capacity could be reached, and it took up to 15 years to establish that capacity. A 25% reduction in the land opportunity cost led to a 63% increase in the steady- state productivity. Sensitivity analysis showed that higher initial conversion of land by farmers to grow energy crop led to faster growth in regional productivity.     

Simulation of Biomass Yield and Soil Organic Carbon under Bioenergy Sorghum Production

Developing sustainable management practices including appropriate residue removal and nitrogen (N) fertilization for bioenergy sorghum is critical. However, the effects of residue removal and N fertilization associated with bioenergy sorghum production on soil organic carbon (SOC) are less studied compared to other crops. The objective of our research was to assess the impacts of residue removal and N fertilization on biomass yield and SOC under biomass sorghum production. Field measurements were used to calibrate the DNDC model, then verified the model by comparing simulated results with measured results using the field management practices as agronomic inputs. Both residue removal and N fertilization affected bioenergy sorghum yields in some years. The average measured SOC at 0–50 cm across the treatments and the time-frame ranged from 47.5 to 78.7 Mg C ha⁻¹, while the simulated SOC was from 56.3 to 67.3 Mg C ha⁻¹. The high correlation coefficients (0.65 to 0.99) and low root mean square error (3 to 18) between measured and simulated values indicate the DNDC model accurately simulated the effects of residue removal with N fertilization on bioenergy sorghum production and SOC. The model predictions revealed that there is, in the long term, a trend for higher SOC under bioenergy sorghum production regardless of residue management.     

Dedicated Herbaceous Biomass Feedstock Genetics and Development

Biofuels and bio-based products can be produced from a wide variety of herbaceous feedstocks. To supply enough biomass to meet the needs of a new bio-based economy, a suite of dedicated biomass species must be developed to accommodate a range of growing environments throughout the USA. Researchers from the US Department of Agriculture’s Agricultural Research Service (USDA-ARS) and collaborators associated with the USDA Regional Biomass Research Centers have made major progress in understanding the genetics of switchgrass, sorghum, and other grass species and have begun to use this knowledge to develop new cultivars with high yields and appropriate traits for efficient conversion to bio-based products. Plant geneticists and breeders have discovered genes that reduce recalcitrance for biochemical conversion to ethanol and drop-in fuels. Progress has also been made in finding genes that improve production under biotic and abiotic stress from diseases, pests, and climatic variations.     

Sources of Biomass Feedstock Variability and the Potential Impact on Biofuels Production

Terrestrial lignocellulosic biomass has the potential to be a carbon neutral and domestic source of fuels and chemicals. However, the innate variability of biomass resources, such as herbaceous and woody materials, and the inconsistency within a single resource due to disparate growth and harvesting conditions, presents challenges for downstream processes which often require materials that are physically and chemically consistent. Intrinsic biomass characteristics, including moisture content, carbohydrate and ash compositions, bulk density, and particle size/shape distributions are highly variable and can impact the economics of transforming biomass into value-added products. For instance, ash content increases by an order of magnitude between woody and herbaceous feedstocks (from ～0.5 to 5 %, respectively) while lignin content drops by a factor of two (from ～30 to 15 %, respectively). This increase in ash and reduction in lignin leads to biofuel conversion consequences, such as reduced pyrolysis oil yields for herbaceous products as compared to woody material. In this review, the sources of variability for key biomass characteristics are presented for multiple types of biomass. Additionally, this review investigates the major impacts of the variability in biomass composition on four conversion processes: fermentation, hydrothermal liquefaction, pyrolysis, and direct combustion. Finally, future research processes aimed at reducing the detrimental impacts of biomass variability on conversion to fuels and chemicals are proposed.© 2015 Battelle Energy Alliance, LLC, contract manager for Idaho National Laboratory.     

Feedstock Crop Production Costs and Biofuel Feedstock Input Costs Associated with the Production of Energy Cane and Sweet Sorghum in the Southeastern USA

Concentration of biofuel feedstock crop production in specific regions of the USA is dependent on the relative comparative advantage of production in a specific region based on several agronomic and economic factors. For the southeastern region of the USA, energy cane and sweet sorghum have been identified as two feedstock crops with the greatest potential for further development of production. This study utilized field trial data from yield studies in Louisiana to develop estimates of feedstock crop production costs and biofuel feedstock input costs for these two crops. Results indicated that feedstock production costs on a harvest yield basis, as well as the related dry matter basis, were heavily dependent on yield level. Economic research from this study indicated that energy cane had a slight cost advantage compared with sweet sorghum, although production of sorghum in certain periods during the growing season was very cost competitive with energy cane.     

Improving Woody Biomass Feedstock Logistics by Reducing Ash and Moisture Content

We examined two practical methods for reducing moisture content and/or ash content in biomass from southern pine harvests. Logging residues are a potential bioenergy feedstock, but contaminants can increase ash content during collection. We found that trommel screens can reduce ash levels in grindings from southern pine roundwood and clean chipped logging residues from 4.0 to 1.4 % and 11.9 to 6 %, respectively. Green whole-tree chips are a widely used form of forest biomass, but are 50 % moisture. Felling and transpirationally drying in-field before chipping reduced moisture from 53 to 43 % and 39 % in 4 and 8 weeks, respectively, without changing ash content (<0.7 %). Finally, we used data from the screening and drying studies in a simulation study to estimate delivered costs for whole-tree chipping and screened and unscreened grinders processing logging and clean chip residue. Whole-tree chipping provided the lowest cost option at ash content levels less than 1 %, and unscreened grinding of clean chip residue produced the least expensive option at 5 % ash.     

Evaluation and Modeling of Bioethanol Yield Efficiency from Sweet Sorghum Juice

One of the challenges with using sweet sorghum as an energy crop is that although fermentation of the juice to ethanol does not require enzymes, the juice can easily spoil. One strategy to avoid spoilage is to harvest the juice in the field, place it into a tanker for transport, and add the yeast immediately to initiate the fermentation process to begin during transport. Hence, it is also important to understand how the fermentation process is influenced by pH, temperature, and dissolved oxygen, since these parameters would not be “controlled” during transport. A full factorial design was applied to examine and optimize yield efficiency of ethanol production for the fermentation of sweet sorghum juice. Bioethanol yield efficiency was modeled using a linear equation. Under optimal pH (5.5), temperature (28 °C), and dissolved oxygen (0%) conditions, a maximum theoretical yield efficiency of 0.75 was achieved for bioethanol produced from M81E variety of sweet sorghum.     

Species Diversity and Biomass Stability

With the current accelerating rate of biodiversity extinction, there is great interest in how species diversity influences ecosystem properties. In this article, we investigate the relationship between species diversity and the stability of community biomass in the face of stochastic perturbations of species' abundances. The model explicitly includes species' interactions. We show that the pattern of species' interactions affects whether the relationship between diversity and biomass stability is positive or negative. In particular, assumptions about community structure influence the relationship between species diversity and community biomass, which in turn influences the diversity-stability relationship. We also discuss the relationship between diversity and another type of stability, the proportional change in community biomass with the extinction or introduction of a species. Regardless of community type, diversity buffers the change in biomass when a species is added or removed.     

Biomass Yield and Nutrient Uptake of Energy Sorghum in Response to Nitrogen Fertilizer Rate on Marginal Land in a Semi-Arid Region

Energy sorghum tolerates adverse climatic and edaphic conditions and has great potential as biofuel feedstock in marginal land. This study investigates the potential energy sorghum biomass production and uptake of nitrogen (N), phosphorus (P), and potassium (K) on a sandy loam marginal land in a semi-arid region, in order to define optimum N fertilizer rate to produce the highest biomass yield with minimal nutrient elimination. Five N rate treatments (0, 60, 120, 180, and 240 kg ha^?1) and two sorghum varieties (sweet type Guotian-8 (GT-8) and biomass type Guoneng-11 (GN-11)) were used. Yield increment was observed as N level increased, but the standout treatment appeared to be N rate of 60 kg ha^?1 which significantly increased biomass yield vs. controls by 68.8% in 2014 and 64.1% in 2015. Biomass yield exhibited non-significant differences between N rate treatments from 60 to 240 kg ha^?1, although the highest biomass yield (9.2–11.9 t ha^?1) was observed in the 120 kg N ha^?1 treatment. Nutrient analysis showed that N, P, and K accumulation in aboveground plants increased with N rate increase, ranging between 32.2 and 119.1, 7.9 and 19.2, and 22.1 and 94.0 kg ha^?1, respectively, for the highest N rate of 240 kg ha^?1. Substantial amounts of N were extracted from the soil in control and 60 kg N ha^?1 treatments, despite the low fertility and organic matter content of the soil. Moreover, nitrogen (N) use efficiency (NUE) was maximized at lower N rates. A decline in physiological N use efficiency (PNUE) resulted in decreased agronomic N use efficiency (ANUE) at higher N rates. Hence, it is concluded that N fertilizer rate between 60 and 120 kg ha^?1 would be the optimal N requirement to facilitate sustainable production of energy sorghum on a sandy wasteland.     

Summary Report on the 2012 Sun Grant National Conference: Science for Biomass Feedstock Production and Utilization

The 2012 Sun Grant National Conference on Science for Biomass Feedstock Production and Utilization was held on 2–5 October 2012, in New Orleans, LA, USA. The Sun Grant Initiative set out to highlight recent advances in science and technology contributing to the deployment of conventional and advanced biofuels and bioproducts from agricultural and forest systems. The Initiative, with sponsorship from the Department of Energy’s Bioenergy Technologies Office (BETO), assembled an agenda focusing on promoting collaboration between academic, industry, non-profit, and government partners. This special issue is comprised of a small sample of conference presentations selected to reflect important research progress and to highlight the range of issues that must be considered as the transition to biomass energy takes hold.     

Managing Spatial and Temporal Switchgrass Biomass Yield Variability

Biorefineries that plan to use switchgrass exclusively will encounter year-to-year variability in feedstock production. The economic success of the biorefinery will depend in part on the ability of the management team to strategically identify land for conversion from current use to the production of switchgrass enabling a flow of feedstock for the life of the biorefinery. The objective of this research is to determine the optimal quality, quantity, and location of land to lease while considering the spatial and temporal variability of switchgrass biomass yield. A calibrated biophysical simulation model was used to simulate switchgrass biomass yields for 50 years based on historical weather data from 1962 to 2011, for three land capability classes for each of 30 counties. Mathematical programming models were constructed and solved to determine the optimal leasing scheme for each of three strategies for a biorefinery that requires 2,000 Mg/day. As expected, a model based on the assumption that the average yield would be obtained in each year finds that production from land identified for leasing would be insufficient to fulfill the biorefinery’s needs in half of the years. In the absence of other sources of biomass, the feedstock shortage would require forced idling of the biorefinery for an average of 29.5 days during these years. Results of a strategy of leasing sufficient land to cover feedstock needs in the worst year from among 50 years for which data are available are compared to that of a strategy enabling year-to-year storage.     

Biomass and Cellulosic Ethanol Production of Forage Sorghum Under Limited Water Conditions

This study presents results from a 2-year evaluation of biomass and cellulosic ethanol (EtOH) production potential of forage sorghum (Sorghum bicolor L. Moench) cultivars differing in brown midrib trait (i.e., bmr12) under dryland (no irrigation) and limited irrigation (2.88 mm?day^?1; subsurface drip) in the semiarid Southern High Plains of the USA. Commercial cultivar Sorghum Partners 1990 (SP 1990, conventional non-bmr) produced significantly more biomass (29–62 %) than a bmr12 cultivar PaceSetter bmr (PS bmr) under irrigated and dryland conditions during both years of this study. However, PS bmr biomass had higher cellulosic EtOH conversion efficiency than SP 1990 in both years according to simultaneous saccharification and fermentation analysis. Irrigation resulted in 26–49 % more biomass and 28–72 % more cellulosic EtOH production during both growing seasons, indicating that limited irrigation had favorable effects on both biomass and biofuel production. In the first year, when precipitation was below average, both cultivars produced similar amounts of cellulosic EtOH. During the second year, when precipitation was above average, higher biomass production of SP 1990 resulted in 28 % higher cellulosic EtOH production than PS bmr when averaged across both irrigated and dryland conditions. The large range of cellulosic EtOH production (1,600 to 3,380 L?ha^?1) during the 2 years of this study was primarily driven by differences in water availability that resulted from precipitation and irrigation. Our findings indicates that chemical composition and biomass yield potential of sorghum cultivars are critical factors that affect biomass and biofuel production under limited water conditions.     

Finasteride Concentrations and Prostate Cancer Risk: Results from the Prostate Cancer Prevention Trial

ObjectiveIn the Prostate Cancer Prevention Trial (PCPT), finasteride reduced the risk of prostate cancer by 25%, even though high-grade prostate cancer was more common in the finasteride group. However, it remains to be determined whether finasteride concentrations may affect prostate cancer risk. In this study, we examined the association between serum finasteride concentrations and the risk of prostate cancer in the treatment arm of the PCPT and determined factors involved in modifying drug concentrations.MethodsData for this nested case-control study are from the PCPT. Cases were drawn from men with biopsy-proven prostate cancer and matched controls. Finasteride concentrations were measured using a liquid chromatography-mass spectrometry validated assay. The association of serum finasteride concentrations with prostate cancer risk was determined by logistic regression. We also examine whether polymorphisms in the enzyme target and metabolism genes of finasteride are related to drug concentrations using linear regression.

Results and Conclusions

Among men with detectable finasteride concentrations, there was no association between finasteride concentrations and prostate cancer risk, low-grade or high-grade, when finasteride concentration was analyzed as a continuous variable or categorized by cutoff points. Since there was no concentration-dependent effect on prostate cancer, any exposure to finasteride intake may reduce prostate cancer risk. Of the twenty-seven SNPs assessed in the enzyme target and metabolism pathway, five SNPs in two genes, CYP3A4 (rs2242480; rs4646437; rs4986910), and CYP3A5 (rs15524; rs776746) were significantly associated with modifying finasteride concentrations. These results suggest that finasteride exposure may reduce prostate cancer risk and finasteride concentrations are affected by genetic variations in genes responsible for altering its metabolism pathway.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00288106","term_id":"NCT00288106"}}NCT00288106     

激光810大豆高产稳产性分析

笔者运用激光技术选育出了激光810大豆,亩产400kg以上,并分析了激光810高产稳产性的原因。     

Impact of Storage Time on the Juice and Sugars Extracted from Chopped and Whole Stalk Sweet Pearl Millet and Sweet Sorghum Biomass

Since they have a high concentrations of fermentable sugars, sweet pearl millet and sweet sorghum are two interesting crops for bioethanol production. However, if the juice is not extracted from the biomass immediately after harvest, the biomass has to be transported and stored for further juice extraction. This delay could affect the amount of juice extracted and its sugar concentration. This paper presents the results of 3 years of experiments where different storage modes (chopped and whole stalks) and various storage time (0 to 14 days) were applied on two different crop species (sweet pearl millet and sweet sorghum). Storing sweet pearl millet as whole stalks for 2 weeks resulted in a water-soluble carbohydrate (WSC) concentration decrease of 52 %, while no significant decrease of the WSC concentration was observed for sweet sorghum. Whole stalks storage is much more efficient than storing the biomass chopped to avoid a rapid sugar loss. However, more juice can be extracted from stored chopped biomass than from stored whole stalks biomass. If the juice cannot be extracted quickly after the harvest, the biomass can be stored as whole stalks to avoid rapid sugar deterioration, especially for sweet sorghum.     

The Origin of the USDA Regional Biomass Research Centers

The U.S. Department of Agriculture (USDA) Regional Biomass Research Centers (RBRC) were created to contribute to the planning, research, and development of entire long-term sustainable biofuel production supply chains based on agricultural and forest-based feedstocks. The intent of the centers is to provide a catalyst that links feedstock genetic development, sustainable production and management, logistics, conversion, co-product production, distribution, and market demand suited to the available economic, social, and natural resources within different regions. The centers provide a coordinated, region-based research focus designed with relatively short-term deliverables to help accelerate the commercial production of biomass and other biofuel feedstocks. The centers provide a leadership structure for coordinating biomass research across the country, providing a national perspective that complements other USDA agency efforts designed to help US rural communities participate in the emerging biofuels and biobased products economy. Through coordination with the RBRC, USDA research and service agency programs and resources have been leveraged with the U.S. Department of Energy (DOE) and other federal department, university, and private industry efforts to help accelerate commercial advancement of advanced biofuel production to promote rural economic opportunities and achieve transportation biofuel policy goals.     

Ultra-Brief Intervention for Problem Drinkers: Results from a Randomized Controlled Trial

Background

There are a number of evidence-based, in-person clinical inteventions for problem drinkers, but most problem drinkers will never seek such treatments. Reaching the population of non-treatment seeking problem drinkers will require a different approach. Accordingly, this randomized clinical trial evaluated an intervention that has been validated in clinical settings and then modified into an ultra-brief format suitable for use as an indicated public health intervention (i.e., targeting the population of non-treatment seeking problem drinkers).

Methodology/Principal Findings

Problem drinkers (N = 1767) completed a baseline population telephone survey and then were randomized to one of three conditions – a personalized feedback pamphlet condition, a control pamphlet condition, or a no intervention control condition. In the week after the baseline survey, households in the two pamphlet conditions were sent their respective interventions by postal mail addressed to ‘Check Your Drinking.’ Changes in drinking were assessed post intervention at three-month and six-month follow-ups. The follow-up rate was 86% at three-months and 76% at six-months. There was a small effect (p = .04) in one of three outcome variables (reduction in AUDIT-C, a composite measure of quantity and frequency of drinking) observed for the personalized feedback pamphlet compared to the no intervention control. No significant differences (p>.05) between groups were observed for the other two outcome variables – number of drinks consumed in the past seven days and highest number of drinks on one occasion.

Conclusions/Significance

Based on the results of this study, we tentatively conclude that a brief intervention, modified to an ultra-brief, public health format can have a meaningful impact.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00688584","term_id":"NCT00688584"}}NCT00688584.     

Production and Analysis of Fast Pyrolysis Oils from Proteinaceous Biomass

Fast pyrolysis of lignocellulosic biomass is a facile method for producing high yields of liquid fuel intermediates. However, because most fast pyrolysis oils are highly oxygenated, acidic, and unstable, identification of feedstocks that produce higher quality pyrolysis liquids is desirable. Therefore, the effect of feedstock protein content was studied by performing fast pyrolysis experiments on biomass with varying protein content. The feedstocks ranged from low-protein content, ??5% up to feedstocks with >40 wt.% protein content. Protein content was not a major factor in the yield of pyrolysis oil or the distribution of biomass carbon into the pyrolysis products. However, elevated levels of protein did cause a deoxygenation effect in the pyrolysis process with more of the oxygen rejected from the biomass as water. The deoxygenation caused the pyrolysis oil from the higher protein containing biomass to have higher energy content. Furthermore, the concentration of basic nitrogen groups caused the pyrolysis oil from the higher protein biomass to shift to a more neutral pH and lower total acid number than has been measured typically for lignocelluloic biomass pyrolysis oils. Some of the pyrolysis oils, particularly those from the mustard seed family presscakes exhibited better thermal stability than low-protein pyrolysis oils.     

Bagasse Silage from Sweet Pearl Millet and Sweet Sorghum as Influenced by Harvest Dates and Delays between Biomass Chopping and Pressing

Bagasse remaining after extracting the juice from crop biomass for ethanol production could be preserved as silage and used in animal feedstock, but the nutritive and conservation attributes of bagasse silage from sweet sorghum (Sorghum bicolor (L.) Moench) and sweet pearl millet (Pennisetum glaucum (L.) R.Br) are not well known. We evaluated the nutritive and conservation attributes of silages made with the bagasse of two species (sweet pearl millet and sweet sorghum) harvested on two dates (August and September) at two sites in Québec (Canada) and ensiled after four delays between biomass chopping and pressing (0.5, 2, 4, and 6 h). Bagasse silages made in laboratory silos were considered well preserved (pH?≤?4.0, NH₃-N?<?100 g kg^?1 total N, lactate?>?30 g kg^?1 DM, no propionic and butyric acids) regardless of species, harvest date, or delay between biomass chopping and pressing. Sweet pearl millet and sweet sorghum bagasse silages had similar total N concentration, in vitro true digestibility of dry matter (IVTD), and in vitro neutral detergent fiber digestibility (NDFD). Bagasse silage made from biomass harvested in August rather than in September had a 4 % greater concentration of total N, a 4 % greater IVTD, and a 8 % greater NDFD. The delay between biomass chopping and pressing did not affect the nutritive and conservation attributes of silages. Juice extraction from the biomass of sweet pearl millet and sweet sorghum did not impair attributes of good silage fermentation but it reduced its nutritive value.