Organic wastes used to make green fuel
New York, Sep 10 (PTI) Scientists, including those of Indian origin, have developed a way to efficiently extract sugars from wood chips and organic forest waste, which may serve as a cheaper, sustainable substitute for petroleum – a raw material for fuel.
“To make greener chemicals and fuel, we are working with plant material, but we do not want to compete with its food value,” said Basudeb Saha, from University of Delaware (UD) in the US.
“So instead of taking corn and extracting its sugars to make ethanol, we are making use of the stalks and cobs left over after the corn is harvested, as well as other kinds of waste like wood chips and rice hulls,” he added.
Industry currently separate out the sugars from the lignin through a two-step process using harsh chemicals and reaction conditions in the first step, and an expensive enzyme in the second step.
This process makes the resulting sugars expensive and the end products, though renewable, less competitive than those produced with petroleum, researchers said.
The team developed a one-step process that integrates the pretreatment step and the hydrolysis of cellulose and hemicellulose in one pot and operates at considerably low temperature (85 degree Celsius) and short reaction time (one hour), which making the method energy efficient.
The key to the technology is the use of a concentrated solution of an inorganic salt in the presence of a small amount of mineral acid, researchers said.
The concentrated salt solution requires a minimal amount of water. The solution swells the particles of wood or other biomass, allowing the solution to interact with the fibres, much like a newspaper swells when water spills on it.
The team integrated the process with another step, called the dehydration reaction, which converts the sugars to furans in the same pot and enables the salt solution to be recycled.
Furans are highly versatile compounds used as starting materials for making speciality chemicals.
“Our process enables – for the first time – the economical production of feed streams that could profoundly improve the economics of cellulosic bioproducts manufactured downstream, not to mention the environmental benefits of replacing petroleum,” said Saha.
The study was published in the journal ChemSusChem.
Source: PTI
