Concept: Ethanol fuel
Agro-industrial wastes are generated during the industrial processing of agricultural products. These wastes are generated in large amounts throughout the year, and are the most abundant renewable resources on earth. Due to the large availability and composition rich in compounds that could be used in other processes, there is a great interest on the reuse of these wastes, both from economical and environmental view points. The economic aspect is based on the fact that such wastes may be used as low-cost raw materials for the production of other value-added compounds, with the expectancy of reducing the production costs. The environmental concern is because most of the agro-industrial wastes contain phenolic compounds and/or other compounds of toxic potential; which may cause deterioration of the environment when the waste is discharged to the nature. Although the production of bioethanol offers many benefits, more research is needed in the aspects like feedstock preparation, fermentation technology modification, etc., to make bioethanol more economically viable.
Fuel ethanol production from sustainable and largely abundant agro-residues such as sugarcane bagasse (SB) provides long term, geopolitical and strategic benefits. Pretreatment of SB is an inevitable process for improved saccharification of cell wall carbohydrates. Recently, ammonium hydroxide-based pretreatment technologies have gained significance as an effective and economical pretreatment strategy. We hypothesized that soaking in concentrated aqueous ammonia-mediated thermochemical pretreatment (SCAA) would overcome the native recalcitrance of SB by enhancing cellulase accessibility of the embedded holocellulosic microfibrils.
- Proceedings of the National Academy of Sciences of the United States of America
- Published about 5 years ago
In the US Corn Belt, a recent doubling in commodity prices has created incentives for landowners to convert grassland to corn and soybean cropping. Here, we use land cover data from the National Agricultural Statistics Service Cropland Data Layer to assess grassland conversion from 2006 to 2011 in the Western Corn Belt (WCB): five states including North Dakota, South Dakota, Nebraska, Minnesota, and Iowa. Our analysis identifies areas with elevated rates of grass-to-corn/soy conversion (1.0-5.4% annually). Across the WCB, we found a net decline in grass-dominated land cover totaling nearly 530,000 ha. With respect to agronomic attributes of lands undergoing grassland conversion, corn/soy production is expanding onto marginal lands characterized by high erosion risk and vulnerability to drought. Grassland conversion is also concentrated in close proximity to wetlands, posing a threat to waterfowl breeding in the Prairie Pothole Region. Longer-term land cover trends from North Dakota and Iowa indicate that recent grassland conversion represents a persistent shift in land use rather than short-term variability in crop rotation patterns. Our results show that the WCB is rapidly moving down a pathway of increased corn and soybean cultivation. As a result, the window of opportunity for realizing the benefits of a biofuel industry based on perennial bioenergy crops, rather than corn ethanol and soy biodiesel, may be closing in the WCB.
Despite ethanol’s penetration into urban transportation, observational evidence quantifying the consequence for the atmospheric particulate burden during actual, not hypothetical, fuel-fleet shifts, has been lacking. Here we analyze aerosol, meteorological, traffic, and consumer behavior data and find, empirically, that ambient number concentrations of 7-100-nm diameter particles rise by one-third during the morning commute when higher ethanol prices induce 2 million drivers in the real-world megacity of São Paulo to substitute to gasoline use (95% confidence intervals: +4,154 to +13,272 cm(-3)). Similarly, concentrations fall when consumers return to ethanol. Changes in larger particle concentrations, including US-regulated PM2.5, are statistically indistinguishable from zero. The prospect of increased biofuel use and mounting evidence on ultrafines' health effects make our result acutely policy relevant, to be weighed against possible ozone increases. The finding motivates further studies in real-world environments. We innovate in using econometrics to quantify a key source of urban ultrafine particles.The biofuel ethanol has been introduced into urban transportation in many countries. Here, by measuring aerosols in São Paulo, the authors find that high ethanol prices coincided with an increase in harmful nanoparticles by a third, as drivers switched from ethanol to cheaper gasoline, showing a benefit of ethanol.
Prospecting macroalgae (seaweeds) as feedstocks for bioconversion into biofuels and commodity chemical compounds is limited primarily by the availability of tractable microorganisms that can metabolize alginate polysaccharides. Here, we present the discovery of a 36-kilo-base pair DNA fragment from Vibrio splendidus encoding enzymes for alginate transport and metabolism. The genomic integration of this ensemble, together with an engineered system for extracellular alginate depolymerization, generated a microbial platform that can simultaneously degrade, uptake, and metabolize alginate. When further engineered for ethanol synthesis, this platform enables bioethanol production directly from macroalgae via a consolidated process, achieving a titer of 4.7% volume/volume and a yield of 0.281 weight ethanol/weight dry macroalgae (equivalent to ~80% of the maximum theoretical yield from the sugar composition in macroalgae).
In this paper a techno-economic analysis for a sugarcane biorefinery is presented for the Colombian case. It is shown two scenarios for different conversion pathways as function of feedstock distribution and technologies for sugar, fuel ethanol, PHB, anthocyanins and electricity production. These scenarios are compared with the Colombian base case which simultaneously produce sugar, fuel ethanol and electricity. A simulation procedure was used in order to evaluate biorefinery schemes for all the scenarios, using Aspen Plus software, that include productivity analysis, energy calculations and economic evaluation for each process configuration. The results showed that the configuration with the best economic, environmental and social performance is the one that considers fuel ethanol and PHB production from combined cane bagasse and molasses. This result served as the basis to draw recommendations on technological and economic feasibility as well as social aspects for the implementation of such type of biorefinery in Colombia.
One of the major challenges in the bioconversion of lignocellulosic biomass into liquid biofuels includes the search for a glucose tolerant beta-gulucosidase. Beta-glucosidase is the key enzyme component present in cellulase and completes the final step during cellulose hydrolysis by converting the cellobiose to glucose. This reaction is always under control as it gets inhibited by its product glucose. It is a major bottleneck in the efficient biomass conversion by cellulase. To circumvent this problem several strategies have been adopted which we have discussed in the article along with its production strategies and general properties. It plays a very significant role in bioethanol production from biomass through enzymatic route. Hence several amendments took place in the commercial preparation of cellulase for biomass hydrolysis, which contains higher and improved beta-glucosidase for efficient biomass conversion. This article presents beta-glucosidase as the key component for bioethanol from biomass through enzymatic route.
To improve the synthesis and quality control of carbon-11 labeled radiopharmaceuticals, we report the fully automated loop syntheses of [(11)C]raclopride and [(11)C]DASB using ethanol as the only organic solvent for synthesis module cleaning, carbon-11 methylation, HPLC purification, and reformulation.
Low ethanol yields and poor yeast viability were investigated at a continuous ethanol production corn wet milling facility. Using starch slurries and recycle streams from a commercial ethanol facility, laboratory hydrolysates were prepared by reproducing starch liquefaction and saccharification steps in the laboratory. Fermentations with hydrolysates prepared in the laboratory were compared with plant hydrolysates for final ethanol concentrations and total yeast counts. Fermentation controls were prepared using hydrolysates (plant and laboratory) that were not inoculated with yeast. Hydrolysates prepared in the laboratory resulted in higher final ethanol concentrations (15.8 % v/v) than plant hydrolysate (13.4 % v/v). Uninoculated controls resulted in ethanol production from both laboratory (12.2 % v/v) and plant hydrolysates (13.7 % v/v), indicating the presence of a contaminating microorganism. Yeast colony counts on cycloheximide and virginiamycin plates confirmed the presence of a contaminant. DNA sequencing and fingerprinting studies also indicated a number of dissimilar communities in samples obtained from fermentors, coolers, saccharification tanks, and thin stillage.
India is the fifth largest primary energy consumer and fourth largest petroleum consumer after USA, China, and Japan. Despite the global economic crisis, India’s economy is expected to grow at 6 to 8 %/year. There is an extreme dependence on petroleum products with considerable risks and environmental issues. Petroleum-derived transport fuels are of limited availability and contribute to global warming, making renewable biofuel as the best alternative. The focus on biogas and biomass-based energy, such as bioethanol and biohydrogen, will enhance cost-effectiveness and provide an opportunity for the rural community. Among all energy sources, microalgae have received, so far, more attention due to their facile adaptability to grow in the photobioreactors or open ponds, high yields, and multiple applications. Microalgae can produce a substantial amount of triacylglycerols as a storage lipid under photooxidative stress or other adverse environmental conditions. In addition to renewable biofuels, they can provide different types of high-value bioproducts added to their advantages, such as higher photosynthetic efficiency, higher biomass production, and faster growth compared to any other energy crops. The viability of first-generation biofuels production is, however, questionable because of the conflict with food supply. In the future, biofuels should ideally create the environmental, economic, and social benefits to the communities and reflect energy efficiency so as to plan a road map for the industry to produce third-generation biofuels.