Cellulosic Ethanol from Agricultural Residues

Yang, Bin; Lu, Ye; Wyman, Charles E.

doi:10.1002/9780813822716.ch9

“…One of the most common and simple technologies for rendering the carbohydrate fraction available for biofuels production is the application of a dilute solution of sulfuric acid (0.5%-2%) at temperatures of 140°C -180°C with residence times of 10-30 minutes [24]. This process leaves a residue that is depleted in hemicellulose but retains most of the cellulose intact, making it an ideal substrate for enzymatic hydrolysis to yield fermentable sugars for ethanol production.…”

Section: Mechanical Thermomechanical and Thermochemical Pretreatmentsmentioning

confidence: 99%

Pretreatment of Lignocellulosic Biomass Using Microorganisms: Approaches, Advantages, and Limitations

Canam¹,

Town²,

Iroba³

et al. 2013

Sustainable Degradation of Lignocellulosic Biomass - Techniques, Applications and Commercialization

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/55088 . IntroductionMuch of Earth s recent geologic history is dominated by periods of extensive glaciation, with relatively low global mean temperatures and correspondingly low atmospheric CO concentrations [ ]. The current interglacial period stands out as an anomaly because the atmospheric CO concentration has risen sharply above the range of approximately -parts per million by volume that has defined the past , years to reach levels that are nearly % higher than the biosphere has experienced over this time frame [ ]. This rapid increase in CO concentration is primarily due to the release of ancient fixed atmospheric CO into the modern atmosphere through the combustion of fossil fuel resources over the past years. Since it is clear from ice core records that atmospheric CO concentration has a strong positive correlation to global temperature, it is expected that changes to global climate are forthcoming [ ]. There are substantial uncertainties regarding the ability of terrestrial and oceanic carbon sinks to absorb this anthropogenic CO on time scales that are relevant to human society [ ], so the continued release of ancient CO into the modern atmosphere at current rates carries with it an important risk of inducing climate changes of unknown amplitude along with a host of ancillary changes that are difficult to predict with certainty. This has led to the search for alternatives to fossil fuels to meet a rising global energy demand, and one such option is the use of extant organic matter to produce energy. This resource contains carbon that was fixed from the modern atmosphere, which means it does not result in a net increase in atmospheric CO upon combustion.

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“…A wide range of options is available for preparing ground biomass for further processing. One of the most common and simple technologies for rendering the carbohydrate fraction available for biofuels production is the application of a dilute solution of sulfuric acid (0.5%-2%) at temperatures of 140°C -180°C with residence times of 10-30 minutes [24]. This process leaves a residue that is depleted in hemicellulose but retains most of the cellulose intact, making it an ideal substrate for enzymatic hydrolysis to yield fermentable sugars for ethanol production.…”

Section: Mechanical Thermomechanical and Thermochemical Pretreatmentsmentioning

confidence: 99%

Yeast Biotechnology: Teaching the Old Dog New Tricks

2015

New Microbial Technologies for Advanced Biofuels

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Additional information is available at the end of the chapter http://dx.doi.org/10.5772/55088 . IntroductionMuch of Earth s recent geologic history is dominated by periods of extensive glaciation, with relatively low global mean temperatures and correspondingly low atmospheric CO concentrations [ ]. The current interglacial period stands out as an anomaly because the atmospheric CO concentration has risen sharply above the range of approximately -parts per million by volume that has defined the past , years to reach levels that are nearly % higher than the biosphere has experienced over this time frame [ ]. This rapid increase in CO concentration is primarily due to the release of ancient fixed atmospheric CO into the modern atmosphere through the combustion of fossil fuel resources over the past years. Since it is clear from ice core records that atmospheric CO concentration has a strong positive correlation to global temperature, it is expected that changes to global climate are forthcoming [ ]. There are substantial uncertainties regarding the ability of terrestrial and oceanic carbon sinks to absorb this anthropogenic CO on time scales that are relevant to human society [ ], so the continued release of ancient CO into the modern atmosphere at current rates carries with it an important risk of inducing climate changes of unknown amplitude along with a host of ancillary changes that are difficult to predict with certainty. This has led to the search for alternatives to fossil fuels to meet a rising global energy demand, and one such option is the use of extant organic matter to produce energy. This resource contains carbon that was fixed from the modern atmosphere, which means it does not result in a net increase in atmospheric CO upon combustion.

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“…Table VIII lists the composition of major lignocellulosic biomass sources. A more detailed analysis of the major components of lignocellulosic agricultural residues has been provided by Yang et al 132 A typical lignocellulosic material, woody biomass, is comprised of the following (with empirical formulae): cellulose C 6 H 10 O 5 ; hemicellulose C 5 H 8 O 4 ; and lignin C 6 H 11 O 2 . The former two macromolecules can both be hydrolysed to fermentable sugars, but lignin cannot.…”

Section: Second Generation Feedstocksmentioning

confidence: 99%

125th Anniversary Review: Fuel Alcohol: Current Production and Future Challenges

Walker

¹

2011

Journal of the Institute of Brewing

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J. Inst. Brew. 117(1), 3-22, 2011Global research and industrial development of liquid transportation biofuels are moving at a rapid pace. This is mainly due to the significant roles played by biofuels in decarbonising our future energy needs, since they act to mitigate the deleterious impacts of greenhouse gas emissions to the atmosphere that are contributors of climate change. Governmental obligations and international directives that mandate the blending of biofuels in petrol and diesel are also acting as great stimuli to this expanding industrial sector. Currently, the predominant liquid biofuel is bioethanol (fuel alcohol) and its worldwide production is dominated by maize-based and sugar cane-based processes in North and South America, respectively. In Europe, fuel alcohol production employs primarily wheat and sugar beet. Potable distilled spirit production and fuel alcohol processes share many similarities in terms of starch bioconversion, fermentation, distillation and co-product utilisation, but there are some key differences. For example, in certain bioethanol fermentations, it is now possible to yield consistently high ethanol concentrations of ~20% (v/v). Emerging fuel alcohol processes exploit lignocellulosic feedstocks and scientific and technological constraints involved in depolymerising these materials and efficiently fermenting the hydrolysate sugars are being overcome. These so-called secondgeneration fuel alcohol processes are much more environmentally and ethically acceptable compared with exploitation of starch and sugar resources, especially when considering utilisation of residual agricultural biomass and biowastes. This review covers both first and second-generation bioethanol processes with a focus on current challenges and future opportunities of lignocellulose-to-ethanol as this technology moves from demonstration pilot-plants to full-scale industrial facilities.

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Cellulosic Ethanol from Agricultural Residues

Cited by 4 publications

References 83 publications

Pretreatment of Lignocellulosic Biomass Using Microorganisms: Approaches, Advantages, and Limitations

Pretreatment of Lignocellulosic Biomass Using Microorganisms: Approaches, Advantages, and Limitations

Yeast Biotechnology: Teaching the Old Dog New Tricks

125th Anniversary Review: Fuel Alcohol: Current Production and Future Challenges

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