Microalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial crops

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Microalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial crops. Author’s Profile. Papers of comparison. Executive Summary. Author’s Profile. (31668482). Background. - PowerPoint PPT Presentation

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Microalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsHi there, welcome to my website. Im Priyadarshinee Boojhawon. I am a third year undergraduate student majoring in Biotechnology and Biomedical Sciences.This unit involves the biotechnology of algae where recently Ive been working on an experiment involving algae which I find very interesting. Ive been reading articles to get an idea how I can do my lab report and I came across biofuel production from algae. I found research in the biofuel production to be very interesting and the use of microalgae and cyanobacteria for the production of biofuel compared to terrestrial crops just caught my attention.The world has been confronted with an energy crisis due to the depletion of finite resources of fossil fuel and they are more likely to be scarce and costly and are considered to be unsustainable.Methods to convert biomass to competitive liquid biofuels are increasingly attractive and are receiving increased attention.The direct conversion of solar energy into liquid fuel using photosynthetic microorganisms such as microalgae and cyanobacteria is an attractive alternative to fossil fuels and they have several advantages into using these organisms.Are Microalgae and Cyanobacteria the raw material for the production of biofuel compared to terrestrial crops? Two scientific papers have been studied for a comparison and an answer to the question.

Authors ProfileAuthors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPersonal Comments(31668482)Microalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsThe term biofuel is referred to as solid, liquid, or gaseous fuels that are predominantly produced from biorenewable feedstock. Biodiesel is produced through the chemical reactions transesterification and esterification by chemically reacting lipids with an alcohol producing fatty acid esters. Biofuel can be produced from both microalgae and cyanobacteria.Microalgae are unicellular photosynthetic microorganism with growing requirements such as lights, sugars, carbon-dioxide, nitrogen, phosphorus and potassium. They have great capacity to convert carbon-dioxide into lipids, protein and carbohydrates in large amounts over short period of time without competing for arable land necessary for agricultural crops. These products can be processed into both biofuels and useful chemicals. Cyanobacteria are photosynthetic microbes, which can absorb solar energy and fix carbon dioxide. Direct conversion of carbon dioxide to biofuels in photosynthetic cyanobacteria can significantly improve the efficiency of biofuel Production and other high value chemicals by modifying amino acid metabolic pathways by using protein engineering and metabolic engineering and by building non-native biosynthetic pathways.Background

Figure 1 shows carbon fixation and main steps of algal biomass technologies.Authors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPersonal CommentsMicroalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsBiofuels from algae for sustainable developmentAyhan Demirbas., (2010), Use of algae as biofuel sources, Energy Conversion and Management. Volume 51,pp 2738-2749.

According to studies in this article, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Industrial reactors for algal culture are open ponds, photobioreactors and closed system. Microalgae contain oils or lipids and fatty acid. The algal oil is converted into biodiesel through transesterification. The algae are harvested from tanks through processes including concentration through different processes. Oil extracted from the algae is mixed with alcohol and an acid or a base to produce fatty acid methylesters that make up the biodiesel. The oil content from microalgae exceeds 80% of dry weight of algae biomass. About 50% of their weight is oil. The yield of oil per unit area is estimated to be from 19,000 to 57,000 L per acre per year, and is 200 times greater than plant/vegetable oils and can produce 30-100 times more energy per hectare compared to terrestrial crops. The calculated cost per barrel would be only $20 while currently a barrel of oil in the US Market is over $100. Article 1Authors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPersonal CommentsBack to Paper ComparisonMicroalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsPhostosynthetic production of fatty acid-based biofuels in genetically engineered cyanobacteria Lu Xuefeng. (2010), A Perspective: Phostosynthetic production of fatty acid-based biofuels in genetically engineered cyanobacteria, Biotechnology Advances.

This article demonstrate how cyanobacteria can be exploited for biofuel production. The cyanobacterium Synechococcus elongatus PCC7942 has been reported to produce the isobutyraldehyde which is used primarily as a chemical intermediate to produce plasticizers, glycols, essential amino acids, polymers, insecticides and isobutanol, a higher alcohol, produced via a keto acid pathway. Coupled with this, microbial production of isoprene, a high volatile hydrocarbon, has been recently demonstrated by an engineered Synechocystis sp. PCC 6803 strain. Moreover, another higher chain alcohol of interest as a biofuel is 1-butanol is produced by S.elongatus and it can be used as a solvent for extraction of essential oil. 1-butanol is proposed to be used as a substitute for diesel and gasoline because of its low hygroscopicity and energy content.Higher energy such as C5-C8 and C4-C8 can be produced by Escherichia coli.Furthermore, biodiesel is made by transesterification of triglycerides purified from plant oils, yielding fatty acid methyl esters and fatty acid esters. Fatty acid can be produced from cyanobacteria. For example, Escherichia coli can be engineered to be an efficient producer of fatty acids. The free fatty acid can be converted into biodiesel by esterification, and to alkanes and alkenes. Hence this concept has been applied to production and secretion of fatty acids leading to production of biodiesel using cyanobacteria.

Article 2Authors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPersonal CommentsBack to Paper ComparisonMicroalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsDemirbas shows that microalgae are very rich in oil. Algae are among the fastest growing plants and 50% of their weight is oil. He also mentioned that microalgae have much faster growth rates than terrestrial crops and that the unit area yield of oil is 7-31 times greater than crops. Moreover the author also compared the chemical compositions of algae from different species and he added that different species of algae may be suited for different types of fuel.He also added that the yield of oil per unit area is estimated to be from 19,000 to 57,000 L per acre per year and is 200 times greater than plant/vegetable oils and can produce 30-100 times more energy per hectare compared to terrestrial crops. Also, the cost would be 5 times cheaper than the current price. (See Article 1 & Article 1 contd)Lu Xuefeng showed that using cyanobacteria to produce chemicals and biofuel is a very good method. Genetic manipulation has permitted engineering of cyanobacteria to produce non-natural chemicals typically not produced by photosynthetic microorganisms. Cyanobacteria can be engineered to install biofuel chemical pathways.He also added that productivity of ethanol in cyanobacteria can be 19,800-22,680 L/acre/year while in plants/terrestrial crops it is very low. (See Article 2 & Article 2 contd)

Paper ComparisonAuthors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPersonal CommentsMicroalgae and Cyanobacteria as raw material for production of Biofuel in comparison to terrestrial cropsFigure 2 shows the proposed biosynthetic pathways for production of fatty acid-based biofuels including fatty acid esters, fatty alcohols and fatty alkanes directly from solar energy and carbon dioxide in cyanobacteria. A theoretical calculation shows that the productivity of ethanol in photosynthetic organism can reach 19,800 L/acre/year. Algeno Biofuels Inc. has developed an innovative cyanobacteria-based technology and is reported to produce ethanol at a rate of 22,680 L/acre/year. In contrast annual yield of ethanol from corn is 1,213 L/acre/year, from sugar cane it is 2,748 L/acre/year andfrom switchgrass it is 1,247 3,062 L/acre/year. Clearly, ethanol production from cyanobacteria is significantly more efficient than from plant feedstocks.So, according to this article compared to general eukaryotic microalgae, cyanobacteria are more amenable to genetic manipulation for installing biofuel producing chemical pathways. Also, the genetic engineering platform for cyanobacteria is well established and cyanobacteria have been shown to be highly tolerant to the introduction of foreign genes.

Article 2 contd

Figure 2Authors ProfilePapers of comparisonBackgroundExecutive SummaryArticle 1Article 2Paper ComparisonPaper Comparison contdCritical CommentArticle 2 contdArticle 1 contdReferencesPer