11-16-2012, 07:53 PM
(This post was last modified: 11-16-2012, 11:22 PM by Administrator.)
Fuels obtained from biological sources are known as bio fuels.
The branch of biotechnology dealing with the exploitation of biological agents to convert it into sources of energy is known as fuel biotechnology. The bio fuels produced should be portable in large quantities in vehicles, should be able to burn in internal combustion engines of vehicles and should be approximately equivalent to petrol in energy content.
Biogas: It is one of the early and largely produced sources of energy. It is produced from biomass by simple burning or using sophisticated technologies of breakdown. It can be produced by small scale production units, recovery and conditions of production is not costly. But the product released is of low yield and some times pure gases are not evolved.
Bio ethanol: Bio ethanol is produced from biomass by the action of various microbes. The production of bio ethanol occurs from two different raw materials.
(i) From sugar and starch crops: The raw materials is acted upon by microbes like Saccharomyces cerevisia, Bacillus licheniformis, Zymomonas
(ii) From cellulosic materials: This involves two method by enzymatic hydrolyses and by chemical hydrolysis. Organisms like Trichoderma reisei, Saccharomyces cerevisiae, Clostridium etc., break down the biomass or rather the cellulose present in the biomass by the production of enzyme cellulase. The cellulose gets converted to sugars which are broken down by any S. cerevisiae into ethanol. In certain cases, the pentose is formed as an intermediate and only genetically modified E. coli can break down this into simple sugars.
The ethanol so produced is recovered from the water-ethanol mixture by distillation utilizing the difference in boiling points of water and ethanol.
Advantages of bio ethanol as a fuel include: The heat of vaporization is much higher than petrol resulting in less heating up of cylinders. The higher octane number than petrol results in higher power production and no pre-ignition of bio ethanol over commercial petrol. Since it is burnt completely, hydrocarbon residue is not released forming a much cleaner fuel. It has comparatively less chances of catching fire during accidents. In commercial market, petrol is mixed with ethanol to produce ‘gasohol’ which yields good energy and high octane number.
It also include negative aspects like it absorbs moisture, the downstream recovery is high, and the engines under ethanol utilizes more fuel than petrol.
Biobutanol:
This is produced from Clostridium acetobutylicum by anaerobic fermentation. The substrate used is molasses. The production has not met with much success as the cost incurred was too high and application of genetic engineering techniques by modifying the organism resulting in high expression; high substrate utilization is being considered.
Bio diesel
Bio diesel is produced mainly by two ways- from lipids and from hydrocarbons by plants and algae
Bio diesel from lipids:
Lipids are source of energy and can be utilized to release the same. Many plants store lipids in their seeds and this can be processed to produce esters of lipid fatty acids. The product seems to resemble diesel hence known as bio diesel. Bio diesel can be used in the natural form without much modification directly as a fuel.
Bio diesel from hydrocarbons:
Certain plants have the ability to accumulate hydrocarbons which can be utilized to produce fuels. The plants that accumulate hydrocarbons do it as latex. The plant species of family Euphorbiaceae, some milk weeds like Asclepias species, and a tree called as C. multijuga has the above said ability.
Plants of the family Euphorbiacae produce latex which has hydrocarbons emulsified in water. Separation or removal of water yields necessary hydrocarbons. The milk weeds also store latex which can be removed and utilized. The tree C. multijuga is a native of Brazil and it fixes nitrogen in its roots and produces a liquid large in volume and which is quite similar to diesel oil. This can be utilized as an efficient source of bio diesel production. Some freshwater and marine algae are also known to deposit hydrocarbons. This also acts as a source of diesel.
Positive features of bio fuel:
The source from which the bio fuel is produced is biological which is renewable in nature resulting in unlimited production without fear of depletion of resources as in the case of conventional sources like oil, petrol etc. The carbon dioxide emission by burning of bio fuels is much less comparatively. The other polluting gases like sulphur dioxide are not released helping in keeping environment clean. They burn completely and so the energy released is high. The left over residue can be used as manure.
Negative points:
Larger volumes of raw material are required to produce a good quantity of bio fuel and the cost of production is also high.
The branch of biotechnology dealing with the exploitation of biological agents to convert it into sources of energy is known as fuel biotechnology. The bio fuels produced should be portable in large quantities in vehicles, should be able to burn in internal combustion engines of vehicles and should be approximately equivalent to petrol in energy content.
Biogas: It is one of the early and largely produced sources of energy. It is produced from biomass by simple burning or using sophisticated technologies of breakdown. It can be produced by small scale production units, recovery and conditions of production is not costly. But the product released is of low yield and some times pure gases are not evolved.
Bio ethanol: Bio ethanol is produced from biomass by the action of various microbes. The production of bio ethanol occurs from two different raw materials.
(i) From sugar and starch crops: The raw materials is acted upon by microbes like Saccharomyces cerevisia, Bacillus licheniformis, Zymomonas
(ii) From cellulosic materials: This involves two method by enzymatic hydrolyses and by chemical hydrolysis. Organisms like Trichoderma reisei, Saccharomyces cerevisiae, Clostridium etc., break down the biomass or rather the cellulose present in the biomass by the production of enzyme cellulase. The cellulose gets converted to sugars which are broken down by any S. cerevisiae into ethanol. In certain cases, the pentose is formed as an intermediate and only genetically modified E. coli can break down this into simple sugars.
The ethanol so produced is recovered from the water-ethanol mixture by distillation utilizing the difference in boiling points of water and ethanol.
Advantages of bio ethanol as a fuel include: The heat of vaporization is much higher than petrol resulting in less heating up of cylinders. The higher octane number than petrol results in higher power production and no pre-ignition of bio ethanol over commercial petrol. Since it is burnt completely, hydrocarbon residue is not released forming a much cleaner fuel. It has comparatively less chances of catching fire during accidents. In commercial market, petrol is mixed with ethanol to produce ‘gasohol’ which yields good energy and high octane number.
It also include negative aspects like it absorbs moisture, the downstream recovery is high, and the engines under ethanol utilizes more fuel than petrol.
Biobutanol:
This is produced from Clostridium acetobutylicum by anaerobic fermentation. The substrate used is molasses. The production has not met with much success as the cost incurred was too high and application of genetic engineering techniques by modifying the organism resulting in high expression; high substrate utilization is being considered.
Bio diesel
Bio diesel is produced mainly by two ways- from lipids and from hydrocarbons by plants and algae
Bio diesel from lipids:
Lipids are source of energy and can be utilized to release the same. Many plants store lipids in their seeds and this can be processed to produce esters of lipid fatty acids. The product seems to resemble diesel hence known as bio diesel. Bio diesel can be used in the natural form without much modification directly as a fuel.
Bio diesel from hydrocarbons:
Certain plants have the ability to accumulate hydrocarbons which can be utilized to produce fuels. The plants that accumulate hydrocarbons do it as latex. The plant species of family Euphorbiaceae, some milk weeds like Asclepias species, and a tree called as C. multijuga has the above said ability.
Plants of the family Euphorbiacae produce latex which has hydrocarbons emulsified in water. Separation or removal of water yields necessary hydrocarbons. The milk weeds also store latex which can be removed and utilized. The tree C. multijuga is a native of Brazil and it fixes nitrogen in its roots and produces a liquid large in volume and which is quite similar to diesel oil. This can be utilized as an efficient source of bio diesel production. Some freshwater and marine algae are also known to deposit hydrocarbons. This also acts as a source of diesel.
Positive features of bio fuel:
The source from which the bio fuel is produced is biological which is renewable in nature resulting in unlimited production without fear of depletion of resources as in the case of conventional sources like oil, petrol etc. The carbon dioxide emission by burning of bio fuels is much less comparatively. The other polluting gases like sulphur dioxide are not released helping in keeping environment clean. They burn completely and so the energy released is high. The left over residue can be used as manure.
Negative points:
Larger volumes of raw material are required to produce a good quantity of bio fuel and the cost of production is also high.
![[+]](https://www.biotechnologyforums.com/images/netpen-pro/collapse_collapsed.png)