Why in News:

• yeast strain that can produce up to 15.5% more ethanol when glucose or lignocellulose biomass — rice and wheat straw — is fermented has been isolated by researchers from the International Centre for Genetic Engineering and Biotechnology, DBT-ICGEB Centre for Advanced Bioenergy Research, Delhi.

Background:

• In India, ethanol production is mostly by fermenting molasses to meet the annual target of 5% blending of petrol with ethanol. But with India setting a target of blending petrol with 10% of biofuel by 2022, other sources such as rice and wheat straw have to be considered. Fermenting lignocellulose efficiently to generate more ethanol than what is currently possible is therefore necessary. To that end, the strain isolated by ICGEB becomes important.

Challenges:

• During the fermentation process, the temperature increases from about 30 degree C to 40- degree C. Since the commercially available yeast strains are good at fermenting at 30 degree C, the fermentor has to be cooled down when the temperature increases. This increases the cost of ethanol production.
• Second, lignocellulose biomass (rice and wheat straw) contains a mixture of hexose and pentose sugar.
• The pretreatment of lignocellulose (to breakdown the recalcitrant structure of the biomass) results in the production of three main inhibitors (furfural, 5-HMF and acetic acid). These inhibitors reduce the fermentation performance of yeast, leading to reduced ethanol production.

Uses of Ethanol:

• When Ethanol is mixed with petrol, such fuel is known as Ethanol Fuel / Gasohol (=Gasoline + Ethanol).
• It can be used with no modification to the vehicle’s engine. (if concentration of ethanol is
• upto 10%). Almost all vehicles of US and Brazil, use such ethanol fuel.

Ethanol Blended Petrol (EBP) Programme:

• It was launched by the Government in 2003 on pilot basis which has been subsequently extended to the Notified 21 States and 4 Union Territories to promote the use of alternative and environmental friendly fuels.
• It aims at blending ethanol with petrol, thereby bringing it under the category of biofuels and saving millions of dollars by cutting fuel imports.
• Ethanol Blended Petrol Programme is being implemented by the Ministry or Oil Marketing Companies (OMCs).
• This intervention also seeks to reduce import dependency for energy requirements and give boost to agriculture sector.