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Graphical abstract Highlights • Ionic liquids and glycerol was comparatively studied as chitosan plasticizer. • Glycerol form a single site hydrogen bonding with chitosan with C-H as ending groups. • Ionic liquids form crosslinked molecular networks with chitosan by hydrogen bonds. • Plasticizer with both hydrogen bonding and hydrophobic group is desired for chitosan. Abstract The use of chitosan natural polymers to replace synthetic polymers is of interest as part of the green materials movement. However, a major challenge of using chitosan material is its rigid and brittle nature associated primarily with its intra- and inter-molecular hydrogen bonds creating a hydrogen bond network. Plasticizers are able to make chitosan flexible, hypothetically by destroying its hydrogen bond networks. Herein, we showed the importance and complicated nature of the chitosan’s hydrogen bond network with respect to its flexibility, through a comparative study of glycerol and ionic liquids plasticizers. The results demonstrated that glycerol’s hydrogen bonding was able to disrupt the chitosan’s hydrogen bond network resulting in a flexible film, but ionic liquids, even with their very strong hydrogen bonding, were not able to plasticize chitosan. This result suggested that the plasticization phenomenon was more complicated than hydrogen bond disruption. A molecular level study by quantum chemistry calculation showed that the efficiency of glycerol as chitosan plasticizer was due to its single hydrogen bonding site, which breaks down the chitosan hydrogen bonding networks, and leave hydrophobic C-H ending groups to limit the formation of inter molecular hydrogen bonds. [ABSTRACT FROM AUTHOR]

[Display omitted] • CNC production on a commercial scale from wood pulp was explored for two scenarios. • Acid recovery process showed a better economic performance. • The MSP of 1 kg of CNC with acid recovery was $4.69. • Acid recovery process required more steam which increased fossil GHGs. Cellulose nanocrystals (CNCs) are biobased materials with many desirable properties such as high aspect ratio, mechanical strength, crystalline nature, and biodegradability. This study developed a commercial-scale process model of CNC production from wood pulp using sulfuric acid treatment and evaluated its techno-economic and environmental performance with and without acid recovery. The results indicated that CNC produced with acid recovery process was financially more profitable with higher project net present values than without acid recovery process but required higher capital which resulted in a longer payback period and lower return on invested capital. The estimated minimum selling prices of CNC produced with and without acid recovery were $4.69/kg and $4.89/kg, respectively. The global warming (GW) impacts of 1 kg CNC production with and without acid recovery were 11.39 and 11.18 kg CO 2 eq, respectively, showing that higher steam use and consequently more fossil fuels were needed in the acid recovery process. [ABSTRACT FROM AUTHOR]

This study investigated the possibilities of making valuable products from corn ethanol byproducts and providing the beverage industries more variety of high quality emulsifiers other than gum arabic. An arabinoxylan-protein gum (APG) was extracted from distillers' grains (DG), a low-value corn ethanol byproduct, and modified through acylation with succinic anhydride. The effects of pH and degree of substitution (DS) on the emulsifying properties of succinylated APG, referred to as SAPG, were investigated. Emulsion particle size and stability of APG and gum arabic were comparable at pH 3.5–6.5. Succinylation could enhance the emulsifying properties of APG. Compared to gum arabic, at pH < 5, SAPG emulsions had larger particle size but comparable stability, whereas at pH > 5, SAPG had much smaller particle size and better stability than gum arabic. The results suggested that SAPG, compared to gum arabic, could be a comparable emulsifier at low pH values and a better emulsifier at neutral pH values. [ABSTRACT FROM AUTHOR]

Model compounds and recalcitrant biomass were studied to elucidate the mechanism of ambient-temperature acid pretreatment of cellulosic biomass for bio-ethanol production. Pure cellulose, a pure hemicellulose and alfalfa stems were pretreated with sulfuric acid under ambient temperature with varied acid loading and time. Changes in water-soluble carbohydrates (WSCs) and chemical components of substrates were determined, and ethanol production via simultaneous saccharification and fermentation (SSF) was studied. The results showed significant amount of WSCs formed, and the WSCs increased with increasing acid loading and pretreatment time. The ethanol yields from pure cellulose were primarily affected by the added ash. Acid loading showed significant positive effect on ethanol production from alfalfa stems, whereas pretreatment time showed much weaker positive effect. However, non-significant amounts of WSCs were removed by washing of dried substrates. It was hypothesized to be because the WSCs adsorbed onto bulk substrates during the freeze-drying step, as supported by experimental results. [ABSTRACT FROM AUTHOR]

This work studied the two-step acid hydrolysis for determining carbohydrates in lignocellulosic biomass. Estimation of sugar loss based on acid hydrolyzed sugar standards or analysis of sugar derivatives was investigated. Four model substrates (starch, holocellulose, filter paper and cotton) and three levels of acid/material ratios (7.8, 10.3 and 15.4, v/w) were studied to demonstrate the range of test artifacts. The method for carbohydrates estimation based on acid hydrolyzed sugar standards having the most satisfactory carbohydrate recovery and relative standard deviation. Raw material and the acid/material ratio both had significant effect on carbohydrate hydrolysis, suggesting the acid to have impacts beyond a catalyst in the hydrolysis. Following optimal procedures, we were able to reach a carbohydrate recovery of 96% with a relative standard deviation less than 3%. The carbohydrates recovery lower than 100% was likely due to the incomplete hydrolysis of substrates, which was supported by scanning electron microscope (SEM) images. [ABSTRACT FROM AUTHOR]

Abstract: This study quantifies the potential impact of biofuel/bioenergy development on the pulpwood market in Wisconsin. Important demand and supply factors to take into account when quantifying the potential spillover effects include: (i) availability of regional forest residues, (ii) forest biomass demand of the Renewable Portfolio Standard (RPS) mandated by the state, and (iii) the slack pulpwood supply due to the recent economic recession. The results indicate that given the limited amount of regional forest residues, demand for primary forest resources over 2.29 million dry Mg will likely spill over into local pulpwood market and have a pronounced impact on pulpwood prices. The price effect could be more substantial if the pulp and paper industry expands production capacity significantly over the same period. [Copyright &y& Elsevier]

Highlights: [•] Furfural was produced from DDG while animal feed value of DDG was also retained. [•] Furfural was produced through dilute acid reaction followed by batch or BRD process. [•] BRD was superior to batch method in furfural yield and purity. [•] The economic model predicted an increased profitability for corn ethanol plants. [•] Animal feed yield was crucial to the economy of the furfural conversion process. [Copyright &y& Elsevier]

• A planning methodology is presented to aid the planning of agricultural AD systems. • A probabilistic approach was used to overcome uncertainty about project parameters. • Herd size was key determinant to selecting location for AD projects. • Geographic distribution and herd size were crucial to profitability of AD systems. • Biomethane potential and electricity price are critical to AD feasibility. Anaerobic digestion (AD) reduces GHG emission and facilitates renewable energy generation. The slow rate of adoption of this technology is often attributed to economic and technical considerations. Collaboration of two or more dairy farms into a centralized AD system can improve the process economics through economies of scale. However, uncertainties related to the process parameters and the scope/scale of the collaborative implementation impede its adoption. This study presents techno-economic optimization model as a design aid to determine ideal location, capacity, and participation level (cluster size) that maximize economic return on a cooperative digester. This study employs a probabilistic approach to overcome uncertainty regarding project parameters such as manure biomethane potential (BMP), project capital, and electricity sale price. Two case studies based on dairy production regions in Wisconsin were developed to test the model and demonstrate its capabilities. Herd sizes and spatial distribution in a given region were found to be critical factors in determining the viability of digestion projects in general, and collaborative digestion systems in particular. The number of simulation runs needed to capture the probability of profitable AD facility establishment was less than 1000 for both case studies assessed. Electricity sale price and biomethane potential of feedstock utilized were found to be the most restrictive to the feasibility of AD adoption. Changing the optimization objective function, to adopting maximization, favored the formation of collaborative AD facilities for both case studies evaluated. [ABSTRACT FROM AUTHOR]

This study presents a comparative cradle-to-gate life cycle assessment (LCA) of distillers grain (DG) gum, a bio-based paper coating binder, and polyvinyl alcohol (PVA). Non-renewable energy use, greenhouse gas (GHG) emissions, and eutrophication potential were assessed for each binder. Economic, mass, and energy allocation were used to allocate the impacts of DG gum production with co-products (ethanol and livestock feed). DG production non-renewable energy use (269 to 183 MJ) surpassed that associated with PVA production (168 MJ). GHG emissions from DG gum production under mass and energy allocations were 28% and 37% lower than PVA production emissions, respectively. Corn cultivation is responsible for 55% to 78% of the eutrophication impacts of DG gum production under energy and economic allocation, respectively. Changes to natural gas consumption and fertilizer runoff had the largest influence on total energy use, GHG emissions, and eutrophication potential of DG gum production. [ABSTRACT FROM AUTHOR]

A two-stage reaction system was developed to synthesize butyl levulinate (BL), a derivative chemical of levulinic acid, from agricultural residue (rice straw). A single reactor was employed during the first processing stage for the conversion of rice straw cellulose to levulinic acid (LA) in a novel co-solvent system consisting of dilute phosphoric acid and tetrahydrofuran. The highest yield of 10.8% wt. LA concentration (i.e., ∼42% of theoretical LA yield) with intermediate residuals concentration of 1.5% wt. glucose and 0.5% wt. 5-hydroxymethylfurfural (5-HMF) on dry weight basis of biomass was obtained at modest reaction conditions. During subsequent esterification reaction, approximately 7.8% wt. BL yield (at 89% conversion yield) was achieved from the solvent extracted precipitate containing majorly LA and residual 5-HMF in the presence of 0.5 M sulfuric acid using n -butanol. Based on comparative esterification results obtained using commercial chemicals (LA and 5-HMF), apparently 5-HMF exhibited ∼8% wt. BL yield through direct synthesis in the presence of sulfuric acid using n -butanol under the same specified reaction conditions. Alongside, effectiveness of co-solvent treatment on rice straw for potential fermentable sugar release (glucose) was investigated by subjecting the respective post-reaction solid residues to enzymatic digestion using cellulase and yielded highest of 11% wt. per wt. solids (27% wt. glucose conversion efficiency), amongst solid residues underwent different processing conditions. [ABSTRACT FROM AUTHOR]

A novel pretreatment with sulfuric acid at ambient temperature had demonstrated positive effects on ethanol production from alfalfa stems. To better understand these effects and help create a process control system, physical parameters (pore dimensions, surface area, and crystallinity index) and the enzymatic digestibility of alfalfa stems were studied in present work. The SEM images showed that more fine particles were present on the surface of alfalfa stems after acid pretreatment. The BET pore size, pore volume, surface area, and crystallinity were increased with increasing acid during pretreatment, might be due to the acid pretreatment hydrolyzed some hemicellulose and amorphous cellulose. Ensiling and wet storage decreased crystallinity, probably due to the swelling increased the pore size of substrates. The enzymatic hydrolysis of alfalfa stems was improved by acid pretreatment because surface damage, improved pore size, pore volume and surface area improved cellulose exposure. Ensiling also improved the enzymatic hydrolysis, likely due to the swelling resulted in increased pore size and broken hydrogen bonding of substrates. [ABSTRACT FROM AUTHOR]

In this study, levulinic acid (LA) was produced from rice straw biomass in co-solvent biphasic reactor system consisting of hydrochloric acid and dichloromethane organic solvent. The modified protocol achieved a 15% wt LA yield through the synergistic effect of acid and acidic products (auto-catalysis) and the designed system allowed facile recovery of LA to the organic phase. Further purification of the resulting extractant was achieved through traditional column chromatography, which yielded a high purity LA product while recovering ∼85% wt. Upon charcoal treatment of the resultant fraction generated an industrial grade target molecule of ∼99% purity with ∼95% wt recovery. The system allows the solvent to be easily recovered, in excess of 90%, which was shown to be able to be recycled up to 5 runs without significant loss of final product concentrations. Overall, this system points to a method to significantly reduce manufacturing cost during large-scale LA preparation. [ABSTRACT FROM AUTHOR]

Concerns over climate change and fossil resources depletion are drivers for increasing efforts to global transition from fossil-based to biobased products. The development of bioenergy and bioproduct systems, however, faces challenges in terms of resource use, environmental impacts, and production costs. Thus, identifying key areas to reduce costs and environmental impacts of biobased products is crucial. Based on the review of recent literature, this study aims to provide insights into the technical feasibility, costs, and environmental impacts of biobased products produced from different renewable biogenic resources, especially in reference to their fossil-based counterparts. Although biobased products are very diverse, this study focuses on the most promising set of biobased materials such as bio-chemicals, bioplastics, bio-adhesives, bicarbonates, nanocellulose, biochar, and activated carbon. By identifying the bottlenecks for reduction of costs and life cycle environmental impacts and the directions for future research needed in this area, this study would be useful for stakeholders of bioeconomy including researchers, policymakers, and producers who want to achieve the costs and environmental impacts reduction goals for sustainable development of biobased products. • Reviewed techno-economic feasibility and environmental impacts of bioproducts. • Bioproducts increase fossil energy savings and reduce greenhouse gas emissions. • Not all environmental impacts are reduced when producing bioproducts. • Residues use less inputs than energy crops thus lower impacts and costs. • Feedstock costs, logistics, capital investment, and scaling drive commercialization. [ABSTRACT FROM AUTHOR]

The concept of co-production of liquid fuel (ethanol) along with animal feed on farm was proposed, and the strategy of using ambient-temperature acid pretreatment, ensiling and washing to improve ethanol production from alfalfa stems was investigated. Alfalfa stems were separated and pretreated with sulfuric acid at ambient-temperature after harvest, and following ensiling, after which the ensiled stems were subjected to simultaneous saccharification and fermentation (SSF) for ethanol production. Ethanol yield was improved by ambient-temperature sulfuric acid pretreatment before ensiling, and by washing before SSF. It was theorized that the acid pretreatment at ambient temperature partially degraded hemicellulose, and altered cell wall structure, resulted in improved cellulose accessibility, whereas washing removed soluble ash in substrates which could inhibit the SSF. The pH of stored alfalfa stems can be used to predict the ethanol yield, with a correlation coefficient of +0.83 for washed alfalfa stems. [ABSTRACT FROM AUTHOR]

Hemicelluloses are promising biopolymers for substituting petroleum-based polymers. Distillers' grains (DG), a residual product from the dry grind ethanol industry, has a high hemicellulose and low lignin content making it an interesting feedstock as a low-cost source of hemicelluloses. This study fractionated DG into an alkali-soluble hemicellulose-rich polymer (DG-HC) and an alkali-insoluble residue (DG-AI). Chemical and 2D-NMR analyses suggested that DG-HC was rich in arabinoxylans, whereas DG-AI was more rich in glucans, along with crude proteins and fat. The DG-HC was made into stand-alone films or thin film coatings on paper, and evaluated by DSC, TGA, FT-IR, corrected water vapor transfer rate and tensile strength. Created DG-HC films were stiff with a Tg of about 174°C. When coated onto paper, DG-HC can effectively increase paper dry and wet tensile strength. The residual DG-AI was characterized showing good potential for animal feed, having approximately 95% in vitro true dry matter digestibility. [ABSTRACT FROM AUTHOR]

Energy crops grown on marginal lands offer an alternative supply of renewable resources while avoiding competition with food crops and supporting feed crops. To sustainably grow energy crops, the economic and environmental impacts of various crop management practices such as the adoption of cover crops, fertilization rates, harvesting methods and its end use applications for animal feed or biofuels should be investigated. In this study, we investigated the life cycle analysis (LCA) and economic evaluation of growing two energy crops (energy cane, and napier grass) on the marginal lands with three fertilizer treatments (0, 100, and 200 kg N ha⁻¹), and with a cover crop (clover, Trifolium incarnatum L) in the southeastern United States (US). Energy crop was harvested once a year in the late fall for biofuel applications, while the Napier grass was harvested twice a year: first harvested early in spring for animal feed and later harvested in the fall for biofuel application. Experimental field data such as biomass yield, crop management practices, farm inputs, and carbon stored in the soil, were determined to assess the global warming potential and the delivered cost of each energy crop. Napier grass had lower global warming (GW) impacts and biomass delivery costs, 34–153 kg CO₂ eq. per oven-dry metric ton (ODMT) and $51–$57 perODMT, respectively than that of energy cane. However, both the energy crops provided carbon sequestrations (−17 and −232 kg CO₂ eq. ODMT⁻¹) and thus net GW impact varied between 51 and (−14) kg CO₂ eq. ODMT⁻¹ based on the treatments. When the napier grass was harvested for both biofuel and fodder applications, the overall GW impacts and the delivered costs were reduced. Therefore, energy crops can be grown in marginal lands for increased carbon sequestration while reducing the GW impacts of energy crops for biofuel production. The integrated environmental and economic analyzes further demonstrated that the energy crop delivered costs and GW impacts could be further reduced, if the energy crops can be utilized for both biofuel and feed applications. • Estimated cost and environmental impacts of producing energy crop on marginal land. • Crop management practices, including cover crop and double harvest, were evaluated. • Global warming (GW) impacts and cost of napier grass were lower than energy cane. • Among all, biomass production with cover crop had the lowest GW impacts and cost. • In napier grass, co-production of biomass and fodder reduced GW impacts and costs. [ABSTRACT FROM AUTHOR]

The meat industry in the US generates considerable amount of slaughterhouse waste (SHW), which is typically converted into more useable products through the rendering process. Although rendering generates sellable fat and meal commodities, it has large environmental impacts because it is energy intensive. Anaerobic digestion (AD) is a promising technology for treating SHW and reducing environmental impact through biogas production to generate heat or electricity, as well as by enabling nutrient recovery and pathogen reduction. This study compared the life-cycle energy use and global warming impact of treating SHW with traditional rendering with AD to produce heat and electricity. The study also considered the co-digestion of SHW with the organic fraction of municipal solid waste (OFMSW) and sewage sludge. A cradle-to-grave life-cycle assessment (LCA) method was used to quantify the energy use and greenhouse gas (GHG) emissions of these systems for treating SHW. We compared three scenarios: (1) AD of SHW, (2) Co-AD of SHW with OFMSW, and (3) Co-AD of SHW with sewage sludge to reference systems of simple rendering and composting. The study findings revealed that the total cradle-to-gate energy use and GHG emissions by treating SHW with AD and co-AD were 0.5−6.7 GJ/1000 kg-SHW and 400−834 kg-CO₂-eq/1000 kg-SHW, whereas for the rendering control scenarios total cradle-to-gate energy use and GHG emissions were 1.9 GJ/1000 kg-SHW and 96.4 kg-CO₂-eq/1000 kg-SHW, respectively. However, considering all the benefits of treating SHW with co-AD, including the displacement of fossil fuel and electricity and nitrogen fertilizers generated as system outputs, these systems perform better than the rendering process. Compared to the reference systems, the GHG reduction potential of treating SHW with co-AD varied between 426.8 and 524.0 kg-CO₂-eq/1000 kg-SHW. Among all input parameters, methane (CH₄) leak from the AD system, and nitrogen fertilizer displacement were the most sensitive parameters affecting the results. By implementing AD of SHW in meat industries in the southeast US, the energy production and GHG emissions reduction potential were estimated to be 22–29 × 10⁶ GJ and 1.6–2.0 × 109 kg-CO₂-eq per year, respectively. The results indicate that the AD of SHW can substantially reduce GHG emissions of the US meat industry as well as produce bioenergy to provide energy security in the US. Image 1 • Co-AD of SHW with a co-substrate can produce energy of 6.03–7.60 GJ/1000 kg-SHW. • Co-AD of SHW with sewage sludge can reduce up to 524.0 kg-CO₂-eq/1000 kg-SHW. • Methane leak and fertilizer displacement substantially impact GHG emissions of AD. • AD of SHW in the southeast US can reduce GHG emissions by 2.0 × 10⁹ kg-CO₂-eq/year. [ABSTRACT FROM AUTHOR]

• Spatial resolution and variations affect environmental assessment and decision-making. • Aggregation of geospatial data showed little influences on GWP. • Aggregation of geospatial data showed significant influences on eutrophication and soil loss. • Selective harvesting at higher resolution can significantly lower environmental impacts. • Harvesting 50% of the total available stover incurred only 15–24% of the total soil erosion. This study assesses the role of spatial-resolution and spatial-variations in environmental impacts estimation and decision-making for corn-stover harvesting to produce biofuels. Geospatial corn-stover yields and environmental impacts [global warming potential (GWP), eutrophication, and soil-loss] dataset for two study areas in Wisconsin and Michigan were generated through Environmental Policy Integrated Climate (EPIC) model and aggregated at different spatial-resolutions (i.e., 100; 1000; 10,000 ha). For each spatial-resolution, decision-making was accomplished using an optimization routine to minimize different environmental impacts associated with harvesting stover to meet varied biomass demands. The results of the study showed that selective harvesting at higher-resolution (or lower-aggregation level) can result in significantly lower environmental impacts, especially at low stover demand levels. Additionally, the increased spatial resolution had more impact in minimizing the environmental impacts of corn stover harvest under a more variable landscape such as terrains and its influences are more pronounced for soil-loss and eutrophication potential compared to GWP. [ABSTRACT FROM AUTHOR]