AET plays key role in green energy project

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ADVANCED Extraction Technology, an East Yorkshire-based micro-business, is helping university experts to extract valuable natural chemicals from agricultural waste.

The business, known as AET, is working on two joint research projects with the University of York.

One of these is seeing AET use super-heated water technology to convert an agricultural waste material, currently used as a low-value animal feed, to a potential raw material for biofuel production.

The project is being carried out with the Biorenewables Development Centre (BDC), based at the York Science Park.

Expert staff at the BDC will then use their scale-up facilities to develop processes with the aim of turning the material into a biofuel, in other words, fuel derived from plant sources.

“Exploring this type of reuse or ‘waste valorisation’ is of great importance, particularly as it offers an alternative source of biofuel to food crops, which is a hot topic of debate and concern,” explained Dr Fabien Deswarte, business development unit manager at the BDC.

“Looking at uses for ‘wastes’ is just one of the ways the BDC is working towards a circular economy, and we are thrilled to be working with AET on this pro-ject.”

AET specialises in using sub-critical water extraction (SWE) technology to produce valuable natural chemicals and extracts from plant biomass.

SWE is based on the phenomenon that when water is heated significantly above the normal boiling point, with pressure applied to keep the water in liquid form, the polarity – the extent to which it can dissolve particular chemical compounds – changes significantly.

Therefore, compounds normally only soluble in polar organic solvents such as alcohols can be successfully extracted from raw materials.

“If a solvent is very polar then it is dissolving things that are water-soluble, if it’s non-polar it’s dissolving oily things. We are making water, which normally only dissolves very polar things, dissolve things which are less polar,” explained Dr Gary Wheatley, director at AET.

SWE can be considered a “green” technology, said AET, as it can replace harmful and flammable organic solvents in extraction processes.

“SWE is normally a very efficient extraction process due to the high diffusion of solvent molecules at elevated temperatures and pressure,” added the firm.

The second project AET is working on with the University of York is with its Green Chemistry Centre of Excellence (GCCE), focusing on anti-oxidants and anti-inflammatories.

AET has signed an agreement with the GCCE to investigate extracting potentially valuable polyphenols from citrus waste. Polyphenols are naturally occurring chemicals found in plants.

This waste is available in large quantities, for example from the juicing industry, but currently has little commercial value and is primarily used to add bulk to animal feed.

Dr Wheatley said: “These citrus polyphenols are expected to exhibit both anti-oxidant and anti-inflammatory properties and may find applications in both food and skincare products.”

“The beauty of these projects is that we are not only finding high-value applications for natural chemicals derived from wastes, but we are also applying ‘green chemistry’ to do this, i.e. not using hazardous chemicals and applying simple, environmentally benign technologies,” said Professor James Clark, director of the GCCE.

Both projects have been made possible through funding at the BDC and the GCCE from the European Regional Development Fund, which is available to eligible small to medium-sized businesses in Yorkshire and Humber.

AET, which is based in Little Weighton, was set up in 2007 by Dr Wheatley and Ken Davison, originally to investigate applications of SWE technology in the production of pharmaceutical compounds from plant sources.

“We still carry out this work but recently have realised that SWE also has great potential for converting agricultural waste and other plant biomass into the precursors (i.e. fermentable sugars) for production of bioethanol and other biofuels”, said Dr Wheat-ley.