Assessing the environmental sustainability of ethanol from integrated biorefineries.
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ABSTRACT:
SUBMITTER: Falano T
PROVIDER: S-EPMC4674963 | biostudies-literature |
REPOSITORIES: biostudies-literature
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| S-EPMC9022439 | biostudies-literature
Project description:The need to encourage individuals as active change agents for sustainability transitions has led researchers across disciplines to conceptualize over 70 constructs to assess relevant dispositions to environmental protection and green consumption behaviors. The generated knowledge is, however, fragmented by an unconsolidated set of constructs developed within parallel literature streams. We, hence, use an integrative review method to capture conceptual and operational similarities and distinctiveness of constructs across disciplines in the literature, attempting to unify the knowledge base. Thereby, we identify 34 conceptually distinct constructs (along with 38 synonyms and 76 scales) relevant for the thematic synthesis on individual-level constructs framing contributions to environmental measures and issues. We followingly propose a taxonomy, systemizing constructs based on their concept type(s) (e.g., value, attitude, behavior) and contextual scope(s) of the environmental challenge (e.g., product choice, household practice) addressed. We capture these dimensions in critically assessing relevant and salient conceptual and operational features. We thus create a consolidated picture of extant constructs capturing individual-level environmental sustainability by which we intend a three-fold contribution to the interdisciplinary field. First, the taxonomy and guiding framework for the choice of constructs should assist substantive researchers in identifying appropriate constructs of interest. Second, the systematic integration of (dis)similar concepts available in parallel literature streams should assist future endeavors aiming at integrating substantive findings with regard to antecedents, consequences, and other relevant variables. Finally, the taxonomy revealed that conceptualizations mainly scatter around specific combinations of types and scopes while others remain unaddressed. Based on our critical assessment of the relevant features and resulting taxonomy, we identify avenues for future research dedicated to (i) enhancing conceptual rigor and measurement quality in the field and (ii) introducing concepts addressing missing but potentially valuable combinations of types and scopes (e.g., antecedents capturing green consumption contexts). We conclude that researchers engaging in the proposed avenues with conceptual, methodological, or empirical contributions should consider four critical aspects to advance knowledge accumulation and prevent fragmentation in the interdisciplinary field. We thereby hope to pave the way for a collective, interdisciplinary knowledge base of concepts used to describe and assess individual's pro-environmental dispositions and practices of green consumption.
| S-EPMC8766306 | biostudies-literature
Project description:BackgroundExpanding biofuel markets are challenged by the need to meet future biofuel demands and mitigate greenhouse gas emissions, while using domestically available feedstock sustainably. In the context of the sugar industry, exploiting under-utilized cane leaf matter (CLM) in addition to surplus sugarcane bagasse as supplementary feedstock for second-generation ethanol production has the potential to improve bioenergy yields per unit land. In this study, the ethanol yields and processing bottlenecks of ammonia fibre expansion (AFEX™) and steam explosion (StEx) as adopted technologies for pretreating sugarcane bagasse and CLM were experimentally measured and compared for the first time.ResultsEthanol yields between 249 and 256 kg Mg-1 raw dry biomass (RDM) were obtained with AFEX™-pretreated sugarcane bagasse and CLM after high solids loading enzymatic hydrolysis and fermentation. In contrast, StEx-pretreated sugarcane bagasse and CLM resulted in substantially lower ethanol yields that ranged between 162 and 203 kg Mg-1 RDM. The ethanol yields from StEx-treated sugarcane residues were limited by the aggregated effect of sugar degradation during pretreatment, enzyme inhibition during enzymatic hydrolysis and microbial inhibition of S. cerevisiae 424A (LNH-ST) during fermentation. However, relatively high enzyme dosages (> 20 mg g-1 glucan) were required irrespective of pretreatment method to reach 75% carbohydrate conversion, even when optimal combinations of Cellic® CTec3, Cellic® HTec3 and Pectinex Ultra-SP were used. Ethanol yields per hectare sugarcane cultivation area were estimated at 4496 and 3416 L ha-1 for biorefineries using AFEX™- or StEx-treated sugarcane residues, respectively.ConclusionsAFEX™ proved to be a more effective pretreatment method for sugarcane residues relative to StEx due to the higher fermentable sugar recovery and enzymatic hydrolysate fermentability after high solids loading enzymatic hydrolysis and fermentation by S. cerevisiae 424A (LNH-ST). The identification of auxiliary enzyme activities, adequate process integration and the use of robust xylose-fermenting ethanologens were identified as opportunities to further improve ethanol yields from AFEX™- and StEx-treated sugarcane residues.
| S-EPMC5934847 | biostudies-literature
Project description:Lighter fluids are consumer products used only at a low-volume scale, representing a realizable goal of fossil fuel replacement by renewables. Physicochemical properties of four fossil-based conventional lighter fluids (Ronsonol, Zippo, Landmann, and Terracotta) and six selected biomass-based chemicals (γ-valerolactone, ethyl-levulinate, ethanol, n-butanol, γ-valerolactone 90% v/v and ethanol 10% v/v, and ethyl-levulinate 90% v/v and ethanol 10% v/v mixtures) as potential biomass-based lighter fluids were assessed. Assessments were carried out in terms of safety, toxicological, and environmental viewpoints, represented by a flash point, boiling point, vapor pressure values, and evaporation rates; oral toxicity measured on rats; and real ethanol equivalent values, respectively. Parameters were collected where available; in the absence of literature data, they were calculated or measured and then analyzed. Finally, multicriteria analysis based on the flash point, boiling point, vapor pressure, toxicity, and ethanol equivalent values revealed γ-valerolactone as a renewable substance, which can be a promising alternative to replace fossil-based lighter fluids because it was awarded as the first in the multicriteria evaluation by obtaining the highest value of the overall scores. In practical usage, however, ignition, combustion experiments, flue gas, and emission analysis are also required to underline its commercial use in the future.
| S-EPMC10832035 | biostudies-literature
Project description:The development and implementation of sustainable catalytic technologies is key to delivering our net-zero targets. Here we review how engineered enzymes, with a focus on those developed using directed evolution, can be deployed to improve the sustainability of numerous processes and help to conserve our environment. Efficient and robust biocatalysts have been engineered to capture carbon dioxide (CO2 ) and have been embedded into new efficient metabolic CO2 fixation pathways. Enzymes have been refined for bioremediation, enhancing their ability to degrade toxic and harmful pollutants. Biocatalytic recycling is gaining momentum, with engineered cutinases and PETases developed for the depolymerization of the abundant plastic, polyethylene terephthalate (PET). Finally, biocatalytic approaches for accessing petroleum-based feedstocks and chemicals are expanding, using optimized enzymes to convert plant biomass into biofuels or other high value products. Through these examples, we hope to illustrate how enzyme engineering and biocatalysis can contribute to the development of cleaner and more efficient chemical industry.
| S-EPMC10952156 | biostudies-literature
Project description:BackgroundThe need for liquid fuels in the transportation sector is increasing, and it is essential to develop industrially sustainable processes that simultaneously address the tri-fold sustainability metrics of technological feasibility, economic viability, and environmental impacts. Biorefineries based on lignocellulosic feedstocks could yield high-value products such as ethyl acetate, dodecane, ethylene, and hexane. This work focuses on assessing biochemical and biomass to electricity platforms for conversion of Banagrass and Energycane into valuable fuels and chemicals using the tri-fold sustainability metrics.ResultsThe production cost of various products produced from Banagrass was $1.19/kg ethanol, $1.00/kg ethyl acetate, $3.01/kg dodecane (jet fuel equivalent), $2.34/kg ethylene and $0.32/kW-h electricity. The production cost of different products using Energycane as a feedstock was $1.31/kg ethanol, $1.11/kg ethyl acetate, $3.35/kg dodecane, and $2.62/kg ethylene. The sensitivity analysis revealed that the price of the main product, feedstock cost and cost of ethanol affected the profitability the overall process. Banagrass yielded 11% higher ethanol compared to Energycane, which could be attributed to the differences in the composition of these lignocellulosic biomass sources. Acidification potential was highest when ethylene was produced at the rate of 2.56 × 10-2 and 1.71 × 10-2 kg SO2 eq. for Banagrass and Energycane, respectively. Ethanol production from Banagrass and Energycane resulted in a global warming potential of - 12.3 and - 40.0 g CO2 eq./kg ethanol.ConclusionsUtilizing hexoses and pentoses from Banagrass to produce ethyl acetate was the most economical scenario with a payback period of 11.2 years and an ROI of 8.93%, respectively. Electricity production was the most unprofitable scenario with an ROI of - 29.6% using Banagrass/Energycane as a feedstock that could be attributed to high feedstock moisture content. Producing ethylene or dodecane from either of the feedstocks was not economical. The moisture content and composition of biomasses affected overall economics of the various pathways studied. Producing ethanol and ethyl acetate from Energycane had a global warming potential of - 3.01 kg CO2 eq./kg ethyl acetate.
| S-EPMC5686913 | biostudies-literature
Project description:Biofuels are being promoted as a low-carbon alternative to fossil fuels as they could help to reduce greenhouse gas (GHG) emissions and the related climate change impact from transport. However, there are also concerns that their wider deployment could lead to unintended environmental consequences. Numerous life cycle assessment (LCA) studies have considered the climate change and other environmental impacts of biofuels. However, their findings are often conflicting, with a wide variation in the estimates. Thus, the aim of this paper is to review and analyse the latest available evidence to provide a greater clarity and understanding of the environmental impacts of different liquid biofuels. It is evident from the review that the outcomes of LCA studies are highly situational and dependent on many factors, including the type of feedstock, production routes, data variations and methodological choices. Despite this, the existing evidence suggests that, if no land-use change (LUC) is involved, first-generation biofuels can-on average-have lower GHG emissions than fossil fuels, but the reductions for most feedstocks are insufficient to meet the GHG savings required by the EU Renewable Energy Directive (RED). However, second-generation biofuels have, in general, a greater potential to reduce the emissions, provided there is no LUC. Third-generation biofuels do not represent a feasible option at present state of development as their GHG emissions are higher than those from fossil fuels. As also discussed in the paper, several studies show that reductions in GHG emissions from biofuels are achieved at the expense of other impacts, such as acidification, eutrophication, water footprint and biodiversity loss. The paper also investigates the key methodological aspects and sources of uncertainty in the LCA of biofuels and provides recommendations to address these issues.
| S-EPMC7735313 | biostudies-literature
Project description:IntroductionWhile many studies have implemented programs to increase sanitation coverage throughout the world, there are limited rigorous studies on the sustainability of these sanitation programs.MethodsBetween 2014 and 2018, the rural Sustainable Sanitation and Hygiene for All (SSH4A) approach was implemented by SNV in sub-Saharan Africa and Asia. Repeated cross-sectional household surveys were administered annually throughout program implementation and 1 to 2 years following completion of program activities. We characterize to what extent sanitation coverage was sustained 1 to 2 years after implementation of this SSH4A intervention.ResultsSurveys were conducted in 12 program areas in 10 countries, with 22,666 households receiving a post-implementation survey. Six of 12 program areas (Bhutan, Ghana, Kenya, both Nepal sites, Tanzania) had similar coverage levels of basic sanitation 1-2 years post-implementation, whereas there were varying levels of slippage in the other program areas (both Ethiopia sites, Indonesia, Mozambique, Uganda, Zambia), ranging from a drop of 63 percentage points in coverage in Ethiopia to a drop of only 4 percentage points in Indonesia. In countries that experienced losses in the coverage of household sanitation, sanitation sharing among neighbors generally did not increase, whereas open defecation did increase. In each of the areas where slippage occurred, the sanitation coverage levels at the final time point were all still higher than the initial time point before SNV started working in these areas. We found several factors to be associated with the sustainability of sanitation coverage, including household socioeconomic status, having household members with disabilities, baseline sanitation coverage levels of the program areas, and rate of change of coverage during program activities.ConclusionsData revealed sustained gains in sanitation coverage in some program areas, yet slippage in other areas. This work may serve to benchmark the sustainability of sanitation interventions in sub-Saharan Africa and Asia.
| S-EPMC9426995 | biostudies-literature
Project description: Not available
| S-EPMC10906299 | biostudies-literature
Project description:BackgroundCharacterizing biodiversity in a habitat or in targeted taxonomically or socioeconomically important groups remains a challenge. Standard DNA-based biodiversity identification tools such as DNA barcoding coupled with high-throughput Next-Generation Sequencing (NGS) technologies are rapidly changing the landscape of biodiversity analysis by targeting various habitats and a wide array of organisms. However, effective use of these technological advances requires optimized protocols and benchmarking against traditional tools. Here we investigate the use of commonly used preservative ethanol as a non-destructive and inexpensive source of DNA for NGS biodiversity analysis of benthic macroinvertebrates. We used the preservative ethanol added to field collected organisms (live sorted bulk benthic samples) as a source of community DNA for NGS environmental barcoding. We directly compare this approach with a DNA barcode library generated using Sanger sequencing of all individuals separated from abenthic sample as well as with NGS environmental barcoding of DNA extracted from mixed/homogenized tissue specimens of the same benthic sample. We also evaluate a multiplex PCR strategy, as compared to commonly used single amplicon workflow, using three newly designed primer sets targeting a wide array of benthic macroinvertebrate taxa.ResultsOur results indicate the effectiveness of ethanol-based DNA in providing sequence information from 87% of taxa identified individually from mixture as compared to 89% in conventional tissue extracted DNA. Missing taxa in both DNA sources were from species with the lowest abundance (e.g. 1 individual) in the benthic mixture. Interestingly, we achieved 100% detection for taxa represented with more than 1% individuals in the mixture in both sources of DNA. Our multiplex amplification regime increased the detection as compared to any single primer set indicating the usefulness of using multiple primer sets in initial amplification of target genes.ConclusionsAlthough NGS approaches have significantly increased the potential of using DNA information in biodiversity analysis, robust methods are needed to provide reliable data and alleviate sample-processing bottlenecks. Here we coupled non-destructive DNA access and a multiplex PCR approach in NGS environmental barcoding for effective data generation from benthic live-sorted samples collected in bulk and preserved in ethanol. Our study provides a possible solution to sampling and vouchering challenges in using benthic samples through next-generation environmental barcoding and facilitates wider utility of DNA information, especially species-specific DNA barcodes, in ecological and environmental studies and real-world applications such as biomonitoring programs.
| S-EPMC3542036 | biostudies-literature