Production of Ethanol from Biomass

It is commonly believed that waste simply biodegrades or decomposes in a landfill. However, since most landfills are kept dry and deprived of oxygen, this is not true. Waste is not supposed to biodegrade in a landfill and some biodegradable products may only be partially biodegradable. When the latter happens, groundwater pollution and gas emissions can lead to more serious problems. 

While we all know that food, leaves, grass clippings, and garden wastes can all go into the compost pile, it is less common to throw a cup or a lid on that compost pile. This is definitely possible through the purchase of GreenGood PLA goods such as cups and cutlery that are 100% biodegradable and compostable. 

The production of crops requires substantial consumption of fertilizer, most of which is produced from nonrenewable sources such as gas. The life cycle analysis indicates that ethanol production from crops is only marginally beneficial for the reduction of consumption of nonrenewables. 

Social justice aspects of sustainability require that one considers the food versus fuel aspects of producing ethanol from food CTops. When arable land is used for the production of fuel, less food is produced, leading to an increase in food prices and an increase in worldwide hunger. 

While there are clear concerns with using food crops as a source of ethanol, other crops, such as wood-type material and specifically fibrous cellulose as a source of biomass, are likely to play a bigger role in the future. Cellulose, one of the carbohydrate polymers present in woody biomass, can serve as a potential raw material for the production of fuel ethanol. 

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Currently, ethanol is produced from sugar beets and from molasses. A typical yield is 72.5 liters of ethanol per ton of sugar cane. Modem crops yield 60 tons of sugar cane per hector of land. Production of ethanol from biomass is one way to reduce both the consumption of erode oil and environmental pollution. Domestic production and use of ethanol for fuel can decrease dependence on foreign oil, reduce trade deficits, create jobs in rural areas, reduce air pollution, and reduce global climate change carbon dioxide build-up. 

Foam fractionation is a promising technique for concentrating proteins because of its simplicity and low operating cost. One such protein that can be foamed is the enzyme cellulase. The use of inexpensively purified cellulase may be a key step in the economical production of ethanol from biomass. We conducted foam fractionation experiments at total reflux using the cellulase component P-glucosidase to study how continuous shear affects P-glu-cosidase in a foam such as a fermentation or foam fractionation process. The experiments were conducted at pH 2.4, 5.4, and 11.6 and airflow rates of 3,... 

At current crude oil prices, the production of ethanol from biomass is not profitable, either. Whether produced from beets, sugar cane, or com, it can become competitive only if it is subsidized. And these subsidies would only be forthcoming for political reasons to please their farmer voters, the French, Brazilian, and United States governments... 

Scheme 1 Carbon cycle energy diagram for the production of H2 from biomass-derived ethanol.18...

Production of Ethanol from Cellulosic Biomass Hydrolysates Using Genetically Engineered Saccharomyces Yeast Capable of Cofermenting Glucose and Xylose... 

The use of recombinant microorganisms for cofermentation is one of the most promising approaches in the field of bioethanol production, though their use for large-scale industrial processes still requires fine-tuning of the reliability of the entire process (2). The technical hurdles of cofermentation increase when real biomass hydrolysates have to be fermented. In fact, whatever the biomass pretreatment, the formation of degradation byproducts that could inhibit the fermentation usually requires the addition of a further detoxification step. Therefore, the production of ethanol from hydrolysates should be considered in its entirety, from the optimal pretreatment to the choice of the proper fermentation process. 

Sedlak, M. and Ho,N.W.Y. (2004). Production of Ethanol From Cellulosic Biomass Hydrolysates Using Genetically Engineered Saccharomyces Yeast Capable of Cofermenting Glucose and Xylose. Appl. Biochem. Biotechnol., 113-116, 403-416. 

An approach to the production of ethylene from biomass that does not involve pyrolysis is ethanol dehydration. The catalytic conversion of syngas to ethanol from low-grade biomass (or fossil) feedstocks, and fermentation ethanol via advanced cellulose hydrolysis and fermentation methods, which make it possible to obtain high yields of ethanol from low-grade biomass feedstocks as well, are both expected to be commercialized in the United States (Chapter 11). Which technology becomes dominant in the market place has... 

Iranmahboob, J. Nadim, F. Monemi, S. Optimizing acid-hydrolysis a critical step for production of ethanol from mixed wood chips. Biomass Bioenergy 2002, 22, 401-404. 

For the efficient production of ethanol from lignocellulosic biomass, several procedural obstacles should be overcome. Based on current research progress, the goal of efficient production of ethanol from lignocellulosic biomass can be realized in the near future. 

In Illustration 15.9-4 we considered the production of ethanol from glucose using the yeast Saccharomyces cerevisiae. In that illustration 0.451 C-moles of ethanol and 0.235 C-moles of biomass of elemental composition CHi.80o.56No.n were produced per C-mole of glucose, using 0.0399 moles of ammonia. Assuming the inlet and outlet streams are maintained at 25°C, and that the work input is negligible, what is the heat load on the reactor ... 

The production of ethanol from sugar derived from starch and sucrose has been commercially dominated by the yeast S. cerevisiae (31). However, the sugar obtained from biomass is a mixture of hexoses and pentoses. Now, most wild-t5 e strains of S. cerevisiae do not metabolize xylose (13). 

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