Process Strategies for the Transition of 1G to Advanced Bioethanol Production
19 Oct 2020-Vol. 8, Iss: 10, pp 1310
TL;DR: In this paper, an overview of the current production, use, and regulation rules of bioethanol as a fuel, as well as the advanced processes and the co-products that can be produced together with bio-ethanol in a biorefinery context.
Abstract: Nowadays, the transport sector is one of the main sources of greenhouse gas (GHG) emissions and air pollution in cities. The use of renewable energies is therefore imperative to improve the environmental sustainability of this sector. In this regard, biofuels play an important role as they can be blended directly with fossil fuels and used in traditional vehicles’ engines. Bioethanol is the most used biofuel worldwide and can replace gasoline or form different gasoline-ethanol blends. Additionally, it is an important building block to obtain different high added-value compounds (e.g., acetaldehyde, ethylene, 1,3-butadiene, ethyl acetate). Today, bioethanol is mainly produced from food crops (first-generation (1G) biofuels), and a transition to the production of the so-called advanced ethanol (obtained from lignocellulosic feedstocks, non-food crops, or industrial waste and residue streams) is needed to meet sustainability criteria and to have a better GHG balance. This work gives an overview of the current production, use, and regulation rules of bioethanol as a fuel, as well as the advanced processes and the co-products that can be produced together with bioethanol in a biorefinery context. Special attention is given to the opportunities for making a sustainable transition from bioethanol 1G to advanced bioethanol.
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TL;DR: In this paper, the significance of biomass sources (such as agricultural and woody crops and residues, agro-food and wood processing industries residues and urban wastes) as feedstocks in the biorefinery, the most relevant biorefinering process technologies of the biochemical and thermochemical conversion pathways that are nowadays under development, and the need of further research and innovation effort to eventually achieve the commercialization and application in the market of different biOREfinery products.
Abstract: The current economy system is based in an intensive consumption of fossil fuels in a way that severely compromise future of the planet due to the severe consequences in climate change. In this scenario, the development of flexible and integrated biorefineries to produce biofuels and bioproducts from renewable biomass sources represent a key tool to perform the transition from a petroleum-based economy to a novel bioeconomy that looks for a more efficient and sustainable global development. This article analyses: the significance of biomass sources (such as agricultural and woody crops and residues, agro-food and wood processing industries residues and urban wastes) as feedstocks in the biorefinery, the most relevant biorefinering process technologies of the biochemical and thermochemical conversion pathways that are nowadays under development, and the need of further research and innovation effort to eventually achieve the commercialization and application in the market of the different biorefinery products.
92 citations
Cites background from "Process Strategies for the Transiti..."
...Figure 2 shows a schematic diagram describing the main stages of this technology, which combines conventional starch and cellulosic ethanol conversion processes [21]....
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22 Jan 2021
TL;DR: The most promising biorefinery approaches that will contribute to the cost-competitiveness of advanced bioethanol production processes are discussed, focusing on innovative technologies and applications that can contribute to achieve a more sustainable and effective utilization of all biomass fractions.
Abstract: The production of so-called advanced bioethanol offers several advantages compared to traditional bioethanol production processes in terms of sustainability criteria. This includes, for instance, the use of nonfood crops or residual biomass as raw material and a higher potential for reducing greenhouse gas emissions. The present review focuses on the recent progress related to the production of advanced bioethanol, (i) highlighting current results from using novel biomass sources such as the organic fraction of municipal solid waste and certain industrial residues (e.g., residues from the paper, food, and beverage industries); (ii) describing new developments in pretreatment technologies for the fractionation and conversion of lignocellulosic biomass, such as the bioextrusion process or the use of novel ionic liquids; (iii) listing the use of new enzyme catalysts and microbial strains during saccharification and fermentation processes. Furthermore, the most promising biorefinery approaches that will contribute to the cost-competitiveness of advanced bioethanol production processes are also discussed, focusing on innovative technologies and applications that can contribute to achieve a more sustainable and effective utilization of all biomass fractions. Special attention is given to integrated strategies such as lignocellulose-based biorefineries for the simultaneous production of bioethanol and other high added value bioproducts.
75 citations
TL;DR: In this paper, a review of the pretreatment technologies for biofuel production from lignocellulosic feedstock is discussed along with the inhibitory compounds generations during pretreatment.
Abstract: Lignocellulose biomass is considered to be the prevalent and economic substrate for biofuel generation. The presence of certain refractory components in biomass causes major obstacle in enzymatic hydrolysis and thus it has to be improved by the advancement of pretreatment technology. The pretreatment focused on the enhancement of hydrolysis by altering the polymeric substance into monomers. A suitable pretreatment converts the biomass into easily accessible components for enzymes and thus enhances fermentation during biofuel production. Notwithstanding the research and development activities focused towards the goalmouth and the integrated pretreatment for biofuel production are needed to be optimised in terms of economic and environmental way. The problems associated with the economic and environmental distress focused on enormous research for several decades in order to replace fossil fuels with the lignocellulosic feedstock. The various approaches were implemented in lignocellulose based biofuel production by concerning the net cost and the energy demand by upgrading the process design. In present review, the pretreatment technologies for biofuel production from lignocellulosic feedstock are discussed along with the inhibitory compounds generations during pretreatment. Furthermore, the energy demand on pretreatment and the techno-economic and environmental aspects were discussed. This review highlights the major aspects in biorefinery process which includes the pretreatment and saccharification of sugar and lignin into biofuels.
33 citations
References
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TL;DR: Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis, thereby increasing the cost of ethanol production from lignocellulosic materials.
5,860 citations
"Process Strategies for the Transiti..." refers background in this paper
...Compared to acid hydrolysis, enzymatic hydrolysis shows certain advantages, such as the milder conditions under which it is performed, it does not use chemicals, and it requires less energy [74,75]....
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3,909 citations
"Process Strategies for the Transiti..." refers background in this paper
...Deep eutectic solvents (DEPs), a class of eutectic mixtures of Lewis or Brønsted acids and bases, are new types of ILs formed from cationic and anionic species [66]....
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TL;DR: This paper reviews the most interesting technologies for ethanol production from lignocellulose and it points out several key properties that should be targeted for low-cost and advanced pretreatment processes.
3,580 citations
"Process Strategies for the Transiti..." refers background in this paper
..., NH4OH, NH3, NaOH, KOH and Ca(OH)2) increase cellulose digestibility mainly by lignin removal [62], causing generally less degradation compounds from sugars and lignin when compared to acid catalysts....
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TL;DR: An updated evaluation of potential target structures using similar selection methodology, and an overview of the technology developments that led to the inclusion of a given compound are presented.
3,536 citations
"Process Strategies for the Transiti..." refers background in this paper
...As a chemical building block, levulinic acid is greatly important for biorefineries [165], serving as feedstock for the production of relevant chemicals, such as fuel additives (methyltetrahydrofuran) and pesticides (δ-aminolevulinic acid), plasticizers (diphenolic acid), and even potential biofuels (methyltetrahydrofuran, valerolactone, and ethyl levulinate) [150]....
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TL;DR: Recent developments in genetic engineering, enhanced extraction methods, and a deeper understanding of the structure of lignin are yielding promising opportunities for efficient conversion of this renewable resource to carbon fibers, polymers, commodity chemicals, and fuels.
Abstract: Background Lignin, nature’s dominant aromatic polymer, is found in most terrestrial plants in the approximate range of 15 to 40% dry weight and provides structural integrity. Traditionally, most large-scale industrial processes that use plant polysaccharides have burned lignin to generate the power needed to productively transform biomass. The advent of biorefineries that convert cellulosic biomass into liquid transportation fuels will generate substantially more lignin than necessary to power the operation, and therefore efforts are underway to transform it to value-added products. Production of biofuels from cellulosic biomass requires separation of large quantities of the aromatic polymer lignin. In planta genetic engineering, enhanced extraction methods, and a deeper understanding of the structure of lignin are yielding promising opportunities for efficient conversion of this renewable resource to carbon fibers, polymers, commodity chemicals, and fuels. [Credit: Oak Ridge National Laboratory, U.S. Department of Energy] Advances Bioengineering to modify lignin structure and/or incorporate atypical components has shown promise toward facilitating recovery and chemical transformation of lignin under biorefinery conditions. The flexibility in lignin monomer composition has proven useful for enhancing extraction efficiency. Both the mining of genetic variants in native populations of bioenergy crops and direct genetic manipulation of biosynthesis pathways have produced lignin feedstocks with unique properties for coproduct development. Advances in analytical chemistry and computational modeling detail the structure of the modified lignin and direct bioengineering strategies for targeted properties. Refinement of biomass pretreatment technologies has further facilitated lignin recovery and enables catalytic modifications for desired chemical and physical properties. Outlook Potential high-value products from isolated lignin include low-cost carbon fiber, engineering plastics and thermoplastic elastomers, polymeric foams and membranes, and a variety of fuels and chemicals all currently sourced from petroleum. These lignin coproducts must be low cost and perform as well as petroleum-derived counterparts. Each product stream has its own distinct challenges. Development of renewable lignin-based polymers requires improved processing technologies coupled to tailored bioenergy crops incorporating lignin with the desired chemical and physical properties. For fuels and chemicals, multiple strategies have emerged for lignin depolymerization and upgrading, including thermochemical treatments and homogeneous and heterogeneous catalysis. The multifunctional nature of lignin has historically yielded multiple product streams, which require extensive separation and purification procedures, but engineering plant feedstocks for greater structural homogeneity and tailored functionality reduces this challenge.
2,958 citations
"Process Strategies for the Transiti..." refers background or methods in this paper
...Alternatively, pretreatments based on lignin solubilization can also yield a solid residue enriched in carbohydrates for subsequent enzymatic hydrolysis, and a liquid lignin side-stream [151], which along with the hydrolysis lignin constitute the “lignin platform” for the production of low-molecular-weight aromatics or materials [152,153]....
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...In the same way, the blending of lignin with polymers, such as methyl methacrylate and styrene, has received special attention in the field of thermoplastic elastomers, polymeric foams, and membranes [153]....
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...The process involves several production techniques, such as the melting spin of lignin, oxidative stabilization of lignin fiber, carbonization under N2, and surface treatment sizing [153]....
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...Lignin depolymerization into low-molecular-weight aromatics is the main approach to produce specialty fuels and chemicals [153,169]....
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...Therefore, the direct use of lignin as a macromolecule for the production of high added-value materials without the need of depolymerization is a promising approach [153,169]....
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