Ethanol biofuel development

Aquino Neto S, Ford JC, Zucolotto V, Ciancaghni P, de Andrade AR. Development of nanostnictured bioanodes containing dendrimers and dehydrogenases enzymes for application in ethanol biofuel cells. Biosens Bioelectron 2011 26 2922-2926. 

Topcagic S, Minteer SD. 2006. Development of a membraneless ethanol/oxygen biofuel cell. Electrochim Acta 51 2168-2172. 

BP has investments in an ethanol plant with DuPont and Associated British Foods. It is also investing in cellulosic ethanol research and developing jatropha as a biodiesel feedstock. BP and DuPont are planning a biobutanol demonstration plant and BP would like to eventually convert their ethanol plant to biobutanol production. BP has a 400 million investment with Associated British Foods and DuPont to build a bioethanol plant in the U.K. that may be converted to biobutanol. It has spent 500 million over 10 years at the Energy Biosciences Institute in California to research future biofuels and 9.4 million over 10 years to fund the Energy and Resources Institute (TERI) in India to study the production of biodiesel from Jatropha curcas. It also has a 160 million joint venture with D1 Oils to develop the planting of Jatropha curcas. 

The Department of Energy (DOE) is helping six firms build cellulosic biorefineries with grants totaling about 385 million. When fully operational, the six plants will produce more than 130 million gallons of cellulosic ethanol a year. DOE is also investing 375 million into three new Bioenergy Research Centers to speed up the development of cellulosic ethanol and other biofuels. 

Similar actions are to be observed in other parts of the world, increasingly with the objective of diversifying the fuel supply in the transport sector. Examples are in Brazil, which has the world s most developed biofuel industry, and where a 25% blend (mainly ethanol) is mandatory, or the Alternative Fuel Standard (AFS) at federal level in the USA, or various biofuel mandates being introduced at state level (see also (EC, 2006b)). 

Notably, several types of liquid biofuels exist or are under development and have the potential to replace fossil fuels, especially in the transportation sector. The focus is on organic fuels such as ethanol, butanol, methanol and their derivatives ETBE, MTBE, which can be produced by fermentation, but also biodiesel and liquid biogas, which can provide interesting biomass-based alternatives to diesel and LPG. 

Although ASPEN-Plus is widely used to simulate petrochemical processes, its uses for modeling biomass processes are limited owing to the limited availability of physical properties that best describe biomass components such as cellulose, xylan, and lignin. For example, Lynd et al. (1) used conventional methods to calculate the economic viability of a biom-ass-to-ethanol process. However, with the development by the National Renewable Energy Laboratory (NREL) of an ASPEN-Plus physical property database for biofuels components, modified versions of ASPEN-Plus software can now be used to model biomass processes (2). Wooley et al. (3) used ASPEN-Plus simulation software to calculate equipment and energy costs for an entire biomass-to-ethanol process that made use of dilute-H2S04 acid pretreatment. 

Softwoods are the predominant species of tree in Canada. In British Columbia, an estimated 2.2 million t of surplus wood residues are generated each year (5), which until now have been of limited use as a commercial product. Bioconversion of these residues into biofuel ethanol and valuable chemicals provides an attractive opportunity for the sustainable development of both renewable energy and Canada s forest resources. 

A "fuel or food" debate is also in progress, because biofuels are made from agricultural products and therefore they drive up food prices. Today 33 nations are at risk of social unrest because of the rise in food prices (most of their families spend 75%-80% of their income on food). In the United States, a fifth of the corn crop is used to brew ethanol and as more com is planted shortages develop in other produce, such as soybeans. 

It is estimated that food production would be severely disrupted if more than 15 billion gallons of com ethanol were produced. At the same time, the OECD (Organisation for Economic Co-operation and Development) estimated that replacement of 10% of America s motor fuels with biofuels would require about one third of all the cropland that is devoted to the production of cereals, oilseeds, and sugar crops. 

The U.S. bioethanol industry is growing rapidly. Production in 2007 was 6.5 billion gallons from 139 bioethanol refineries. A further 4 billion gallons of capacity are expected to come online by the end of 2008. In 2006,14% of the corn crop in the United States was used to produce ethanol and probably as a result, com prices increased by 25% in 2007. In the United States 90 plants operated in 2006 and 160 in 2007. Just in Iowa, 42 ethanol and biodiesel plants are in operation and an additional 18 are under construction. A study by the Organization for Economic Cooperation and Development calculated that in order to meet 10% of the fuel requirements of the United States, Canada, and the EU, 30% to 70% of their crop area would have to be devoted to biofuels. 

The CASH process was developed by cooperation between Canada, the USA and Sweden. In this method, hydrolysis occurs in two steps with dilute sulfuric acid at a temperature around 200 °C (pressure 8-25 bar) and the fermentation of sugars by yeast to ethanol. It has been shown that by using SO2 and dilute sulfuric acid in two steps, this increases the sugar and ethanol yield, since the amount of inhibitors such as furfural is decreased. The process was developed for raw materials such as sawdust and other residues from trees. The ethanol yield is about 30% of the energy in the raw material and there are also by-products, with up to 40% of the energy content in solid form (lignin), which can be used as biofuel. 

W. Korbitz, New trends in developing biodiesel worldwide, in Asia Biofuels Evaluating Exploiting the Commercial Uses of Ethanol, Fuel Alcohol Biodiesel, Singapore, 2002. 

Production of ethanol via yeast-catalyzed fermentation of plant carbohydrates is an ancient process. Professor John Thompson (Lane Community College, Eugene, Oregon, USA) has developed an interesting variant of this process using molasses as the feedstock. We use this experiment to introduce the ideas of catalysis (yeast enzymes), azeotropes, density, and biofuels, as well as the technique of simple distillation of ethanol using 19/22 glassware (5). 

Here the typical example is the inhibitor effect of ethanol on yeast growth. Considerable efforts are made by the biocompanies to develop yeast strains that are tolerant to high ethanol concentrations since this will give considerable savings in, e.g., production of biofuel by fermentation. 

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