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The objective of this work was to examine opportunities for reducing the overall cost of lignocellulose hydrolysis to fermentable sugars. Primary sludge (PS), a negative cost lignocellulosic feedstock, was hydrolyzed sludge using a commercial cellulase preparation (Cellic® CTec2) in presence of non-ionic surfactants. Polyethylene glycol (PEG) 4000 facilitated the highest hydrolysis yield of 74.4% which represented a 2-fold increase over the control without surfactant. Response surface methodological analysis at four variables (hydrolysis time, solids, enzyme, and surfactant loadings) revealed that enzymatic hydrolysis was significantly enhanced by the interactive effect of all factors with solids and enzyme loadings as the most significant parameters (p < 0.05). Using ultrafiltration, 40% of the cellulase enzyme was recovered from the enzymatic hydrolysate and reused on fresh PS substrate. The hydrolysate fermentabilty was evaluated in production of 9.7 g/L bioethanol at 92% ethanol yield using Saccharomyces cerevisiae , and in production of 37.8% biolipids by the oleaginous yeast Cutaneotrichosporon oleaginosum at a carbon to nitrogen ratio of 40. The compression load of a sample prepared from the unhydrolyzed PS solids was 102% higher than Portland cement. The potential for valorization of the unhydrolyzed solids as reinforcement material warrants further investigations. • Enzymatic hydrolysis of primary sludge was optimized using statistical methods. • Surfactants increased the enzymatic hydrolysis efficiency and yield. • About a third of the enzyme activity was recovered and recycled. • Enzymatic hydrolysate was evaluated in bioethanol and biolipid production. • Unhydrolyzed solids from sludge hydrolysis was assesses as reinforcement material. [ABSTRACT FROM AUTHOR]

Cellulose, the most abundant terrestrial biopolymer, has immense potential for a range of applications, such as textiles, biomedical applications, and sustainable building components. Due to the recalcitrant nature of lignocellulosic materials, various alkaline and acid pretreatment methods have been developed to recover mono sugars for fermentation. Simultaneous production of bioethanol and nanocrystalline cellulose (NCC) from pretreated Formosan alder biomass was conducted in two stages. Formosan alder biomass was treated using unbleached kraft (UEK), acid steam explosion (SEP), and bleached acid steam explosion (BSEP) and hydrolyzed using cellulase. Filter paper (FP) and alpha-cellulose were used as positive controls. Bioethanol fermentation using E. coli Ko11 was conducted. Residual biomass was further recovered to produce NCC. After 96 h enzyme hydrolysis, the highest sugar yields were 383.4 and 329.84 mg glucose/g biomass for the FP and UEK samples. The highest bioethanol fermentation yields were 4.18 and 3.62 g bioethanol/g biomass for FP and UEK samples. During enzyme hydrolysis of the biomass, crystallinity increased. NCC yields were 613.93 nm (68%) and 1583 nm (73%) for the FP and UEK samples. The negative impact of lignin content was reflected in the particle length of the final NCC. Further lignin removal is required for optimal NCC production. This study showed that Formosan alder biomass could be used to produce both bioethanol and NCC. • This study integrates sustainable energy with advanced nanomaterial processing. • Prove that a native species is able to fulfill the future need. • Feedstock crystallinity is a key factor impacting acid hydrolysis efficiencies. • Degree of delignification process is dictating final bioethanol yields. • Nanocrystalline cellulose yields were 73% for unbleached kraft pulp as the feedstock. [ABSTRACT FROM AUTHOR]

This paper describes the impact pathway approach for estimating an economic value of pollution effects of acetaldehyde (CH 3 CHO) associated with bioethanol vehicle transport in Oslo as a climate policy. The approach rests on results obtained in an innovative measurement campaign and by means of air pollution dispersion-models, followed by an impact assessment and economic valuation of the potential externalities. This makes a state-of-the-art methodological technique to reach greater knowledge on the economic costs of urban air quality impacts resulting as a side effect of climate change policy. The social economic costs estimated in this paper are then compared to likely social economic benefits (i.e. avoided social economic damage cost) of reduced nitrogen dioxide (NO 2 ) and carbon dioxide-(CO 2 ) emissions. The carcinogenic risk from long-term inhalation exposure to acetaldehyde emissions, leads in this paper to a moderate cost estimate associated with the combustion of bioethanol in vehicles in Oslo. Productivity and welfare loss is the dominant cost component, whereas the direct medical costs constitutes only a small part of the total social economic costs. The costs however, expect to be significantly lower than the combined economic benefits from reduced emissions of target compounds, such as carbon dioxide and nitrogen dioxide. [ABSTRACT FROM AUTHOR]

The ever growing concerns about the impact of first generation bioethanol on food chain and on biodiversity have shifted the focus of research to second generation (2G) bioethanol technologies. The 2G-bioethanol's production relies on biomass feedstock that could provide a more sustainable energy generation without compromising food security and environment. Indeed, this production process exploits non-food crops, food crops residues, wastes of wood-based or food-based industries such as wood chips, skins or pulps from fruit pressing, respectively. Nevertheless, the industrial process of 2G-bioethanol's production is still in its infancy, indeed the future and the sustainability of the 2G-bioethanol strongly depend upon the development of the current technology. In this paper particular attention will be paid to the role of thermophilic microorganisms and their enzymes to the biotechnology's development of the bioethanol's production process. [ABSTRACT FROM AUTHOR]

Abstract Promoting biofuel to replace fossil fuels and alternative utilization schemes to replace conventional measures of biomass waste disposal have been considered a priority to mitigate CO 2 emissions. Despite fewer land resources and higher reliance on imported energy and raw material resources, the potential for bioenergy supply in a place like Taiwan should be fully investigated. This paper presents a case study regarding the utilization of waste biomass derived from an enhanced production of rice paddy and from the forest sector in Taiwan for biofuel production. In this study, the carbon balance for the two aforementioned bioenergy production scenarios was calculated. The amount of biomass waste expected to be derived from rice husk and rice straw produced from currently planted paddy and from reactivated fallow rice paddy was estimated. Forest sector wastes consist of biomass derived from processing domestically harvested and post-consumer harvested wood products. The projection was made up to 2065. The overall annual bioenergy providing potential of the biomass, estimated by this study, to replace gasoline through bioethanol production and residual combustion and to substitute coal for power generation via combustion were approximately 222.37 PJ and 206.77 PJ, respectively. These values represent 332.56% and 323.24% of the current level of bioenergy supplies, compared to the 76.4 PJ from biomass and waste incineration in 2016. This is the first time the bioenergy potential of post-consumer harvested wood products is being identified. Highlights • Potential of bioenergy from forest sector is identified. • Potential of bioenergy supply from reactivated fallow rice paddies is identified. • 254.06 PJ can be converted by bioethanol production and combustion of residue. • 246.92 PJ can be converted by obtained by combustion. • Up to 332.56% of the current level of bioenergy supplies can be obtained. [ABSTRACT FROM AUTHOR]

Abstract: This issue of the Journal of Cleaner Production is based upon papers presented at the 1st International Workshop Advances in Cleaner Production (CP) held in São Paulo, Brazil, in 2007. The conference had the short-term purpose of deepening the Brazilian discussion on “The Roles of Cleaner Production in the Sustainable Development of Modern Societies”, and it had the long-term objective of providing an on-going interdisciplinary forum for knowledge development and exchange on Cleaner Production (CP) and Sustainable Development. This issue is devoted to papers covering a broad range of perspectives of CP practices and strategies. A special focus is placed upon methodological tools designed to support effective decision-making pertaining to quantitative benefits from CP. The ten papers provide insights from research designed to holistically integrate CP to help society make effective progress to sustainability. Papers cover the importance of informal knowledge, as complementary to formal knowledge, in performing effective ‘Environmental Impact Assessments.’ One paper explores the roles of radical and incremental innovation in the context of alternative automotive technologies. Benefits of Ecodesign are explored in two papers; one concerning its integration with remanufacturing to extend the life of used products and one focusing the adoption of ‘Emergy Environmental Accounting,’ as a complementary decision-making tool. The development of the Brazilian LCI database for ‘hydroelectric power generation’ and its contribution to support regionally relevant LCA studies is highlighted in one paper. The complete production chains of biodiesel and bioethanol are evaluated by using global methodologies, which help in the development of more objective and effective solutions. A “compensatory area”, calculated in terms of emergy, is proposed in order to work in a sustainable way for bamboo production. Finally, a paper about a novel approach for recycling used PET is also included. [Copyright &y& Elsevier]

The article reassesses a recent case study on six bioethanol production processes in China, to develop a methodology that discriminates the most energy-efficient process. The original research explored the joint method of Life Cycle Assessment and Data Envelopment Analysis (LCA + DEA). However, DEA is sensitive to problems with a disproportionate number of variables to alternatives and LCA usually requires analysis with several inputs and outputs. The original research indicated two sources as being tied for energy efficiency, which is not relevant to decision-makers aiming to invest in the most efficient process. The method proposed here uses a combinatorial and probabilistic approach to improve discrimination and create scenarios for the reduction of inputs and the increase of outputs, even for efficient processes. Results show that the proposed method has better discriminatory power than the referenced paper. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) and polypropylene (PP) can be synthesized from biomass through dehydration, dimerization, and metathesis reactions from ethanol or methanol-to-olefin reaction of synthesis gas. This paper examines the socioeconomic aspects of such biomass-derived resin production, which are composed of environmental impacts quantified by life cycle analysis (LCA) and the structure of generated value flows specified by structural path analysis (SPA) based on a Japanese input–output table. Missing inventory data were estimated by process simulation using Aspen Plus™ and Aspen HYSYS™ with design information extracted from the literature, patents, and design heuristics. LCA based on actual and demonstration plants with process simulation shows the environmental advantage of biomass-derived resins on greenhouse gas (GHG) emissions reduction. PE production has the largest effect on GHG emissions reduction, followed by bioethanol from a gasoline mixture, and PP. The uncertainties in agricultural processes also influence the potential application of international and domestic bioethanol production and synthesis gas obtained from the gasification of waste woods. According to SPA results for gasoline, PE, PP, and plastic products, the cyclicality of resins and plastic products, which was quantitatively analyzed as the total cyclic cash flows from target products to final demands, is much larger than that of gasoline. Based on these results, biomass-derived resin production has the potential to increase added values in an economy, with a corresponding decrease in GHG emissions. [ABSTRACT FROM AUTHOR]

Seaweed is a key biomass for the development of a biobased economy because it contains valuable components such as proteins, sugars, nitrogen and phosphorus. This paper analyses innovative offshore seaweed cultivation for the production of biorefinery feedstock. The biomass is converted into three products: bioethanol, liquid fertilizer and protein-rich ingredient for fish feed. We performed comparative life cycle assessment of a base case and six alternative production scenarios in order to maximize the benefits and minimize the trade-offs in environmental performance of future macroalgal biorefineries (MABs). The results show that the base case provides a net reduction in climate change factors, i.e. −0.1·10 2 kg CO 2 eq. per ha of sea cultivated despite a cumulative net energy demand of 3.9·10 4 MJ/ha, 13% of which originates from fossil sources. Regarding the environmental performance of the system, we obtained a reduction in marine eutrophication of −16.3 kg N eq./ha, thanks to bioextraction of nitrogen. For the base case the net impact on human toxicity (carcinogenic effects) was 2.1·10 −4 comparative toxic units per ha of cultivation. The increase in human toxicity is seven times greater than the system can deal with, however reduction of materials for the cultivation lines, i.e. iron ballast, reduces human toxicity to 0.2·10 −5 comparative toxic units. Externalities from the use of biofertilizer affect the non-carcinogenic effects of the system, resulting in 20.3·10 −4 comparative toxic units per ha. Hotspots in the value chain show that biomass productivity is the main constraint against being competitive with other energy and protein producing technologies. Minor changes in plant design, i.e. use of stones instead of iron as ballast to weight the seeded lines, dramatically reduces human toxicity (cancer). Including engineered ecosystem services in the LCA significantly improves the results. As such, an increase in soil carbon stock represents 15% of the climate change mitigation provided by the MAB system. The study shows that MABs can contribute to a regenerative circular economy through environmental restoration and climate mitigation. [ABSTRACT FROM AUTHOR]

The tequila industry in Mexico generates large amounts of lignocellulosic residues from the cultivation fields as well as from the tequila processing industries. Nowadays, these residues are disposed, but they could be used as feedstock for a biorefinery. Before implementing a biorefinery system to treat the residues from the tequila industry in Mexico, it is necessary to assess the economic and environmental performance of the entire supply chain for biofuel production. Developing a proper optimization framework for supply chain management in the tequila industry in Mexico that will consider all the activities involved along with the conflicting objectives of its daily operation represents a scientific challenge. Therefore, this paper presents a multi-objective optimization approach for designing such a supply chain that accounts for the simultaneous maximization of the net present value and environmental performance of the network. The environmental objective function accounts for impacts in ecosystem quality, human health and damage to resources. These are quantified through the eco-indicator 99 method. Numerical results show that the implementation of a biorefinery system in Mexico based on the residues from the tequila industry can provide significant economic and environmental benefits. Particularly, results indicate that the best economic solution shows a profit of 7.9 × 10 8 USD/year. Furthermore, the distributed system involving several central and distributed processing plants allows obtaining significant economic improvements. Finally, the results reported through Pareto curves allow identifying several solutions that are appealing for decision makers. [ABSTRACT FROM AUTHOR]

In this study, we calculated the water footprint (WF) of second-generation bioethanol and hypothesized that second-generation bioethanol feedstock in response to the gradual depletion of fossil fuels has contributed to exorbitant international oil prices. To resolve these problems, countries worldwide have actively engaged in developing alternative energy plans to reduce their dependence on petroleum. Bioethanol is a critical choose items of biofuels, and increased use of biofuels for transportation is expected to substantially raise the level of competition for freshwater resources. In this paper, Taiwan's second-generation bioethanol demonstration plant is used as an example to calculate the WF of second-generation bioethanol. Using bagasse and rice straw as raw materials, the water footprint are 268.8 L H 2 O/L EtOH and 4674.9 L H 2 O/L EtOH, respectively, which is considerably lower than that of first-generation bioethanol. In this study, we proposed two sources of feedstock that are suitable for future second-generation bioethanol: (1) nonfood crop materials; and (2) domestic waste (e.g., food waste). The results of this study can be used by countries interested in using biofuels to formulate and implement energy policies that will enable them to develop renewable energy sources and simultaneously consider the management and application of water resources. [ABSTRACT FROM AUTHOR]

Life cycle environmental performance of lignocellulosic ethanol produced through different production pathways and having different co-products has rarely been reported in the literature, with most studies focusing on a single pre-treatment and single co-product (electricity). The aim of this paper is to understand the life cycle energy use and greenhouse gas (GHG) emissions implications of alternative pre-treatment technologies (dilute acid hydrolysis, ammonia fiber expansion and autohydrolysis) and co-products (electricity, pellet, protein and xylitol) through developing a consistent life cycle framework for ethanol production from corn stover. Results show that the choices of pre-treatment technology and co-product(s) can impact ethanol yield, life cycle energy use and GHG emissions. Dilute acid pathways generally exhibit higher ethanol yields (20-25%) and lower net total energy use (15-25%) than the autohydrolysis and ammonia fiber expansion pathways. Similar GHG emissions are found for the pre-treatment technologies when producing the same co-product. Xylitol co-production diverts xylose from ethanol production and results in the lowest ethanol yield (200 L per dry t of stover). Compared to producing only electricity as a co-product, the co-production of pellets and xylitol decreases life cycle GHG emissions associated with the ethanol, while protein production increases emissions. The life cycle GHG emissions of blended ethanol fuel (85% denatured ethanol by volume) range from -38.5-37.2 g CO2 eq/MJ of fuel produced, reducing emissions by 61-141% relative to gasoline. All ethanol pathways result in major reductions of fossil energy use relative to gasoline, at least by 47%. [ABSTRACT FROM AUTHOR]

Abstract: Alongside with biofuel development, social acceptance issues have been underestimated. While social acceptance can emerge as powerful barrier for biofuel development, this article provides discussion on social acceptance in biofuel context. An acceptance framework based on life cycle biofuel production had been referred for a better understanding on social acceptance issues. Malaysia has been referred for the discussion as the country has faced with acceptance issue in their biofuel program. The discussion point out different societal groups will demand specific consideration for either support or oppose biofuel. This paper concludes that biofuel development will be constraint if social acceptance issues remain neglect. [Copyright &y& Elsevier]

Abstract: The methodologies, approaches and indicators for assessing the impacts of freshwater usage are still evolving. The development of the water footprint concept has been an important step in this direction but the existing methodologies mainly assess the quantity of water used rather than the related impacts. Although there is a recognised need to consider the latter, particularly on a life cycle basis, the difficulty is that there are little or no reliable data on water usage in life cycle databases; furthermore, there is no agreed life cycle impact assessment method for estimating impacts related to freshwater use. However, there have been some methodological developments which propose methods for inventory modelling and impact assessment for water use in life cycle assessment. This paper reviews some of these approaches and discusses their strengths and limitations through a case study, which considers the impacts of freshwater consumption from corn-derived ethanol produced in 12 different countries. The results show a huge variation in the results between different methods and demonstrate the need for a standardised methodology for assessing the impacts of water use on a life cycle basis. Specific recommendations for further research in this field have been made accordingly. [Copyright &y& Elsevier]

Selective fermentation of reducing sugars in cane juice harnesses the advantageous productivity of high-yielding sugarcane cultivars for increasing products from limited arable land. Without this technology, the altered compositions of cane juice often lead to additional environmental impacts due to increased consumption of externally supplied energy and compensated yield of sugar. In this paper, the effects of coordinated transition of sugarcane farming and sugar milling on the yield of final products, energy consumption, operability in the crystallization process, and economic feasibility were analyzed in simulation across various sugarcane cultivars. An integrated sugarcane farming and sugar milling process model (SugaNol) was extended from a previous work to consistently balance mass and energy considering the characteristics of the selective fermentation technology. A case study demonstrated that the coordinated introduction of selective fermentation with the high-yielding cultivar enhanced sugar production by 8.5% and ethanol production by 17.9%, improved operability in the crystallization process, and lead to a cleaner production by achieving above without consuming additional fossil fuels, although the market price of ethanol should be under 95 JPY L−1 for profitability. Furthermore, the specific characteristics of cultivars to make selective fermentation economically feasible are presented as a guideline for future cultivar development. Image 1 • A process model of combined sugar and ethanol production was developed. • The model can consider agricultural options and selective fermentation technology. • A set of options expects increases in sugar by 8.5% and ethanol by 17.9%. • Busy operation could be avoided even if bad-quality sugarcane is fed. • The request to cultivar development could be visualized through modeling. [ABSTRACT FROM AUTHOR]

The world in general, and Cameroon in particular, are facing three major problems which are population increase, natural resource decrease and climate change. This work focuses on assessing the environmental impact of the production of second-generation liquid and gaseous biofuels by means of the life cycle assessment method, in order to contribute to sustainable development with emphasis on environmentally concerned decision-making and appropriate choice of technologies. The increasingly essential Life Cycle Assessment method is at the heart of this work. Avocado, cocoa and peanut residues have been converted on a laboratory scale to second generation gaseous biofuels (biogas) and liquid biofuels (ethanol). Biomethane yields are 177, 127 and 73 mL/g for avocado seed, cocoa pods and peanut shells respectively. When it comes to bioethanol, avocado seed, cocoa pods, and peanut shells produced yields of 178, 61 and 49 mL/kg biomass respectively. Based on the annual production of the three crops, 200,000 kg and 30,376,960 m3 of bioethanol and biomethane respectively can be produced at the national level of Cameroon. The SimaPro software version 9.1.1.1, the Ecoinvent database v.3.6 and the ReCiPe Midpoint impact method v.1.04 were used for the assessment. All categories of resulting environmental impacts are assessed and quantified. The categories with the most significant impacts are land use, global warming, Human non-carcinogenic toxicity, Terrestrial ecotoxicity, Fossil resource scarcity and water consumption observed in the agricultural phase. Global warming, Land use and Terrestrial ecotoxicity are the hot spots observed in the process of converting biomass into bioethanol and biomethane. The main sources of detected impacts are the processes of seed production, the use of electricity, distilled water and chemicals during the process of converting waste to biofuel on a laboratory scale. This laboratory-scale work will serve as a reference for decision-making of pilot plants and then large-scale production of liquid and gaseous biofuels with the objective of promoting the development of a sustainable biomass-energy industry based on avocado seeds, cocoa pods and peanut shells through identification of critical factors. • Agricultural sector is one of the main economic sectors in Cameroon. • Agricultural by-products can be converted in biofuels. • The environmental impacts of the conversion of agricultural biomass are analyzed. • The laboratory scale conversion is discussed compared to conventional fuels. [ABSTRACT FROM AUTHOR]