Research underway to produce bioethanol and biohydrogen from silkworm-rearing waste

Subject :Science and Tech

Section: Biotechnology

Context:

The Central Sericultural Research and Training Institute (CSRTI) in Mysuru has taken up a pilot-scale project to produce bioethanol and biohydrogen from mulberry shoots and silkworm excrement.

Details:

The studies at CSRTI assume significance in the wake of the government of India’s plans to step up the blending of bioethanol with petrol as part of the efforts to reduce dependence on fossil fuels.
During silkworm rearing, the larvae consume mulberry leaves and leave behind the shoot and its litter.
Currently, more than 10 lakh tonnes of mulberry shoots and a couple of thousand tonnes of silkworm litter are generated annually in India.
The mulberry shoot and silkworm litter contain more than 50 per cent cellulose, which is the raw material for the production of biorefineries.
These can be used for the production of 2G second-generation bioethanol and biohydrogen.

Ethanol:

Ethanol or ethyl alcohol (C2H5OH) is a clear colourless liquid, it is biodegradable, low in toxicity and causes little environmental pollution if spilt.
Ethanol burns to produce carbon dioxide and water.
Ethanol is a high-octane fuel and has replaced lead as an octane enhancer in petrol. By blending ethanol with gasoline we can also oxygenate the fuel mixture so it burns more completely and reduces polluting emissions.
The most common blend is 10% ethanol and 90% petrol (E10).
Vehicle engines require no modifications to run on E10 and vehicle warranties are unaffected also. Only flexible fuel vehicles can run on up to 85% ethanol and 15% petrol blends (E85).

Bioethanol, derived from crops, offers several benefits compared to conventional fuels:

Sourced from renewable crops, it’s not reliant on finite resources (like cereals, sugar beet, and maize).
Reduces greenhouse gas emissions as fuel crops absorb CO2 during growth, aiding in cutting emissions from road transport, which contributes significantly to overall emissions.
Blending bioethanol with petrol extends the lifespan of dwindling oil supplies, ensuring better fuel security and reducing reliance on oil-producing nations.
Boosts the rural economy by promoting the cultivation of necessary crops.
Biodegradable and less toxic than fossil fuels, contributing to environmental preservation.
When used in older engines, it reduces carbon monoxide emissions, thereby enhancing air quality.
Easily integrates into the existing road transport fuel system without requiring engine modifications, allowing for blending of up to 5% with conventional fuel. Produced using familiar fermentation methods, it can be distributed through existing petrol forecourts and transportation systems.