Report on Microbial Production of Fatty Acid Derived Fuels and Chemicals from Plant Biomass

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  • Topic: Fatty acid, Fatty acid metabolism, Ethanol fuel
  • Pages : 6 (2382 words )
  • Download(s) : 198
  • Published : December 4, 2012
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Report on “Microbial production of fatty-acid-derived fuels and chemicals from plant biomass”

Research into alternative energy sources has been a more relevant issue as petroleum will be limited in the future. Finding a suitable replacement that is close enough to petroleum is extremely difficult. Ethanol from corn grain and biodiesel from soybeans have been particularly successful. However, as one study states: Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. (Hill) It is clear from this research that biodiesel is the much more efficient and clean energy source. It must still be considered that there may be times in the future where sources of energy become limited, and so all resources must be accounted for. In a study by Dr. Knothe, frying oils used, before and after cooking in restaurants, were tested for their fatty acid profile using gas chromatography and proton nuclear magnetic resonance spectroscopy (Knothe). This study was invalidated by the study by Canakci stating, “Using food-grade vegetable oils is not economically feasible since they are more expensive than diesel fuel” (Canakci). According to Dr. Canakci, “the main obstacle for commercialization of biodiesel is its high cost.” Nonetheless, both Knothe and Canakci focused on aims of conserving energy and waste by considering potential feedstocks such as cooking oils, restaurant greases, soapstocks and animal fats for the production of biodiesel. Rising energy costs and apprehension over global and environmental damage have prompted research for producing sustainable renewable fuels and chemicals. It has been found that using microbial conversion of sustainable, mass produced feedstocks, particularly biomass carbohydrates, has the prospect of being a cost efficient and high energy fuel source. It is necessary to begin taking proactive steps to find alternative sources of energy that are both more environmentally friendly as well as efficient. The growing shortage of fossil fuel deposits has placed urgency on this research. Although the production of fuels from the processing of fatty acids from plant and animal oils has been in use since the beginning of the 20th century, the need for new sources of energy has been a relatively contemporary issue. A wide range of more modern chemical products are in demand. With this rise in demand have come a more competitive and higher priced food market as well as issues with environmental consequences and controversial land usage. The most efficient solution to this problem is the development of a renewable energy source by a fermentation process that will be both economical and lasting. Fatty acids consist of long alkyl chains and are the basis of most fuels. Fatty acids are a primary metabolite that provide chemical and energy storage for cells. E. coli is a microorganism that can easily be mass produced and can be used, through fermentation, to produce fatty acid metabolites at a rate of 0.2 g l-1 h-1. E. coli consists of about 9.7% lipid and generates a product-dependent mass of 30-35%. E. coli, therefore, can be used to synthetically redirect fatty acid metabolism to produce fuel and other necessary chemicals. Fatty acyl-ACP is produced from microbial fatty acid biosynthesis and is used by cells as structural or storage lipids. However, fatty acid biosynthesis is impeded by the buildup of fatty acyl-ACP feedback. Cytoplasmic thioesterase has the function of hydrolyzing the acyl-ACPs, deregulating fatty acid biosynthesis, and overproducing and secreting high...
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