BIOETHA2: Contribution to the development of the 2nd generation bioethanol production chain (original) (raw)
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Suitability of various plant species for bioethanol production
Agronomy Research
The aim of this research was to investigate glucose yield from different sorts of biomass and their suitability for bioethanol production. The amount of glucose obtained from different samples was also compared with their cellulose, hemicellulose, lignin content and in some cases with harvesting time. Dilute acid pretreatment at temperature of 150°C was used together with enzymatic hydrolysis. Herbaceous biomass from 7 different species was investigated: hemp, sunflower, energy grass, reed, silage, Jerusalem artichoke (Helianthus tuberosus) and Miscanthus saccharifloris. Hemp had the highest cellulose content of 53.86%, while Jerusalem artichokes contained only 21-26% of cellulose. The highest lignin content was found in energy grass and silage, 9.65% and 9.02%, respectively. The most important properties of herbaceous material for bioethanol production and high glucose yields are high cellulose content and availability of biomass. In compliance with the cellulose concentrations, the best glucose yield of 312.7g kg-1 of biomass was obtained from hemp samples and the lowest results of 122.7g kg-1 of biomass from sunflower.
Second generation bioethanol production: A critical review
It is a popular fact that the world's dependency on fossil fuel has caused unfavourable effects, including lessening crude oil reserve, decreasing air quality, rising global temperature, unpredictable weather change, and so on. As the effort to promote sustainability and independency from fossil fuel, bioethanol is now favoured as the blend or fossil petrol substitute. However, the feedstock functionality of first generation bioethanol production is restricted due to its edibleness since it would clash the feeding purpose. Second generation bioethanol production fulfils the impractical gap of first generation since it employs non-edible feedstock sourced from agriculture and forestry wastes. Lignocellulosic and starchy materials in them are convertible to fermentable sugars that are able to be further processed, resulting anhydrous bioethanol as the end product. This paper critically reviews the existing variance of second generation bioethanol production methodologies, namely pre-treatment, hydrolysis, fermentation and distillation, as well as the worth of second generation production for future reference. The discussions in this paper are also fit as the fundamental for feasible planning of second generation bioethanol production plant.
State of the Art and Future Trends of Bioethanol Production
With efforts to reduce global reliance on fossil fuels and lower the greenhouse gas emission, an increasing search for renewably sourced materials, which can be used as feedstock for biofuel production, is ongoing in the past few decades. At the present, ethanol is the most common alternate fuel and is already produced on a fair scale, representing a sustainable substitute for gasoline in passenger cars. Basically, in Brazil ethanol is produced through the fermentation of sugar cane molasses. In the United States ethanol is produced by fermenting starch crops that have been converted into simple sugars, and the major feedstock for this fuel is corn. Various countries have been increasing their ethanol production as well, such as India (using sugar cane), Thailand (cassava), France (sugar beet), China (corn) and Canada (wheat), among others. Though these agricultural commodities are major issues for both food and fuel economies, they are likely to be insufficient in the near future, presenting great challenges for food processors and biofuels producers in the 21 st century. Alternatively, the conversion of cellulosic material into ethanol is relatively low up to date, compared to sugar or starch crops, leading the need to develop fermentation processes that can convert energy crops, such as grasses, and agricultural by-products, such as straw and corn stover, into bioethanol, allowing high conversion of both hexoses and the difficult to ferment pentoses into ethanol at high yields. Therefore, the search for technological breakthrough is on the high, aiming to develop technologies for effectively converting agricultural and forestry lignocellulosic residues to fermentable sugars.
Issues with increasing bioethanol productivity: A model directed study
Korean Journal of Chemical Engineering, 2010
We explore a way to improve the efficiency of fermentation of lignocellulosic sugars (i.e., glucose and xylose) to bioethanol in a bioreactor. For this purpose, we employ the hybrid cybernetic model developed by Song et al. (Biotechnol and Bioeng, 103: 984-1000, 2009), which provides an accurate description on metabolism of recombinant S. cerevisiae due to its unique feature of accounting for cellular regulation. A comprehensive analysis of the model reveals many interesting features of the process whose balance is critical for increasing the productivity of bioethanol. In particular, the addition of extra xylose to the medium may increase ethanol productivity (a somewhat counterintuitive result as xylose metabolism is slower!), but one that must be orchestrated with control of other important variables. Effects of xylose addition are shown to be different for different reactor environments. In a batch culture, xylose addition substantially improves ethanol productivity at low sugar concentration (e.g., about 45% up by increasing initial xylose concentration from 10 to 30 g/L with glucose concentration of 20 g/L), but worsens it at high sugar concentration (e.g., about 10% drop by increasing xylose concentration from 40 to 160 g/L with glucose concentration of 80 g/L). On the other hand, the productivity of chemostats is constantly improved by increasing the ratio of xylose to glucose level in the feed. It is found that multiple local maxima can exist in chemostats and, consequently, optimal composition for mixed sugars is different depending on the allowable range of xylose addition. Batch operation, however, is found to be superior when mixed sugars are consumed slowly, while continuous operation becomes attractive for rapidly metabolized sugars such as pure glucose. Optimal reactor configurations for given lignocellulosic sugars are shown to depend on calculated operating curves. Reasonably close comparison of model simulations with existing batch fermentation data provides support in part to the value of the current effort. The lesson that emerges is the importance of modeling in improving the efficiency of bioprocesses.
1 Bioethanol Production via Enzymatic Hydrolysis of Cellulosic Biomass
2000
Energy availability, supply and use play a central role in the way societies organize themselves, from individual welfare to social and industrial development. By extension, energy accessibility and cost is a determining factor for the economical, political and social interrelations among nations. Considering energy sources, human society has dramatically increased the use of fossil fuels in the past 50 years in a way that the most successful economies are large consumers of oil. However, geopolitical factors related to security of oil supply, high oil prices and serious environmental concerns, prompted by global warming-the use of petrol for transportation accounts for one-third of greenhouse gas emissions (Wyman, 1996)-have led to a push towards decreased consumption. Indeed, the world's strongest economies are deeply committed to the development of technologies aiming at the use of renewable sources of energy. Within this agenda, the substitution of liquid fuel gasoline by renewable ethanol is of foremost importance. Brazil has been a front-runner in the use of renewable fuels. The substitution of gasoline by ethanol started in 1975, when the Brazilian Government launched the "Proálcool Program" (Programa Nacional do Álcool). At the time of the first oil crisis, in the 1970s, the country imported 85% of its oil needs and the potential for ethanol production from sugarcane as a transportation fuel was in good agreement with the Government policy regarding energy supply independence. The Proálcool Program included incentives for distilleries and automobile companies that made ethanol-only cars. Although in the mid-1970s environmental concern was not a major driving force for substituting the use of gasoline, it is worth pointing out the global environmental benefits that have resulted from this policy since then. 1 Document prepared for "The Role of Agricultural Biotechnologies for Production of Bioenergy in Developing Countries", an FAO seminar held in Rome on
Global warming alerts and threats are on the rise due to the utilization of fossil fuels. Alternative fuel sources like bioethanol and biodiesel are being produced to combat against these threats. Bioethanol can be produced from a range of substrates. Cellulose rich substances which are generated in tons in agricultural countries like India can be used for the production of bioenergy in the form of bioethanol with the help of microbial catalytic enzyme cellulose. Celluloses and hemicelluloses, when hydrolyzed into their component sugars, can be converted into ethanol through well established fermentation technologies. In this review, technologies and modern trends for bioethanol production using cellulosic agricultural wastes is discussed. This review assesses the following topics: cellulose in agriculture waste, raw materials for bioethanol production, microorganisms for bioethanol production, ethanol production technologies, cellulosic ethanol, current bioethanol production processes and trends in bioethanol production development. Indeed, the world's strongest economies are deeply committed to the development of technologies aiming at the use of renewable sources of energy. In this view, the substitution with fuel, bioethanol is of foremost importance.
Systemic analysis of production scenarios for bioethanol produced from ligno-cellulosic biomass
… . Agron. Soc. Environ, 2010
Defining alternatives for non-renewable energy sources constitutes a priority to the development of our societies. One of these alternatives is biofuels production starting from energy crops, agricultural wastes, forest products or wastes. In this context, a "second generation" biofuels production, aiming at utilizing the whole plant, including ligno-cellulosic (hemicelluloses, cellulose, lignin) fractions (Ogier et al., 1999) that are not used for human food, would allow the reduction of the drawbacks of bioethanol production (Schoeling, 2007). However, numerous technical, economical, ethical and environmental questions are still pending. One of the aims of the BioEtha2 project, directed by the Walloon Agricultural Research Centre, is to define the position of bioethanol produced from lignocellulosic biomass among the different renewable energy alternatives that could be developed in Wallonia towards 2020. With this aim, and in order to answer the numerous questions in this field, ...
Exploration of Biomass for the Production of Bioethanol: "A Process Modelling and Simulation Study"
Renewable Energy Research and Application, 2021
Bio-ethanol is a clean and renewable fuel that is gaining a significant attention mainly due to its major environmental benefits and its production from diverse resources. The campaign for establishment of bio-refineries and encouragement of fossil fuels is gradually gaining a greater attention. In this research work, we seek to comparatively investigate the material requirement, production yield, and total equipment cost involved in the rice-husk and maize-cob transformation into the bio-ethanol fuel for a large-scale production using a process modeling and simulation study in order to promote the potential investors' interest. This analysis is carried out using a simulator (Aspen HYSYS) and a computational package (MATLAB). The evaluation entails modeling, simulating, and material and energy analysis including the process equipment sizing and cost for the plants. The comparative material analysis of the yield from the model process for the use of biomasses reveals that 9.94 kg and 7.32 kg of fuel-grade bio-ethanol is obtained using 0.03 kg and 0.02 kg of enzymes for every 1 kg of rice-husk and maize-cob charge in the plant, respectively, per hour. Analysis of the plants' energy flow shows that the maize-cob transformation into the bio-ethanol fuel requires more energy than the rice-husk-based plant, confirming that the maize-cob conversion is more energy-intensive than the rice-husk conversion. Moreover, the equipment cost analysis indicates that it costs 4739.87and4739.87 and 4739.87and1757.36 in order to process 1 kg of biomass (rice-husk and maize-cob) into fuel-grade bio-ethanol, respectively, per hour. Ultimately, the findings of this work identify the rice-husk's use to be of high yield, while maize-cob makes the production less capital-intensive.