Turning biomass into biofuel requires the breakdown of primary energy-rich component of the biomass, cellulose. Cellulose is a kind of polysaccharide, a compound formed from the bonding of many sugars into one. For the production of biofuels, the bonds between these many sugars must be broken so the energy could be generated by further processing these sugars. But breaking the bonds is not as easy as it sounds as the bonds are extremely strong and need a proper chemical reaction to complete the feat. Now the question arises that what are the candidates suitable for this job? The answer is various catalysts such as enzymes.
What are Enzymes:
Enzymes are a kind of biological catalysts that occur in the form of proteins and are used by cells of living organisms to catalyze various chemical reactions related with cell metabolism. With the advent of life on earth, enzymes have also evolved with the cells and are capable of undertaking metabolic reactions of a wide variety of living cells.
Enzymes as catalysts:
When acting as catalysts, enzymes increase the rate of reaction in living cells. When used in industrial applications, they help in speeding up the production processes of a variety of products that too at costs lower than chemicals.
A common example of industrial use of enzymes is in speeding up the process of breaking down of starch into sugars during the production of ethanol.
Enzymes are extremely specific in regards to the substance it binds with as well as the catalyzed reaction. So, enzymes can be seen catalyzing only a specific kind of chemical reaction or a group of close-knit or closely related chemical reactions.
An amazing property of enzymes is the fact that they only accelerate a chemical reaction but while doing so, do not undergo any permanent change themselves. As their job gets finished in a chemical reaction, enzymes become inactive.
Use of Enzymes in biofuel production:
Many enzymes are commonly used for the conversion of biomass into biofuels.
The nonrenewable sources of energy are speedily depleting from the face of earth and there is an inevitable demand for biofuels that can be developed from the abundant biomass currently available and that will continue to inhibit earth in abundance during any time in the future.
Other than the practically never ending feedstock for biomass on the face of earth and their renewable nature, there are many other environment related benefits attached with the concept of biofuels, such as less production of CO2, reduced levels of carbon oxides, sulphur oxides and particulates and other emissions.
To match the production of the biofuels with their ever increasing demands, scientists are developing advanced biochemical processes by using enzymes. The research in this field is targeted at improving efficiency and reducing the negative impacts of the production processes on the environment as well as improving the quality of the biofuels produced.
Benefits of Enzymes:
Enzymes are known to overcome many drawbacks associated with the use of traditional chemicals as catalysts for biofuel generation. For instance, the use of enzymes allows consumption of less energy in the production process. Enzymes can also utilize unrefined feedstock such as waste oil, without even needing the separation of free fatty acids that may be present in abundance in the feedstock, which is not possible with conventional catalysts. Also, if enzymes are used in the production of bioethanol from hydrolysis of cellulose, the utility cost of the process is greatly reduced as compared to conventional catalysts as no subsequent treatment of the byproduct is required and the process is carried out at mild conditions.
However, there are also several challenges involved with the use of enzymes as catalyst in the production of biofuels, most importantly, the cost. Therefore, to make their use economical for the process, enzymes are required to be used repeatedly. For this, enzymes are mostly used in their immobilized form which has a considerable effect on certain things such as operational stability, inhibition by reactants and/or products and the exhaustion of enzyme activity. So new processes that could prevent the inhibition of enzymes and that could allow a continuous separation of product is needed to be developed