Squeezing proteins out of orange peel

For students at the School of Life Sciences and Environmental Technology, the Netherlands’ grass clippings and orange peel in the rubbish bin are not merely waste. They extract proteins from them that can be used to produce food.

In a biobased economy, biomass is used as efficiently as possible. Recent years have seen growing research into biobased technologies – also at Avans. The School of Life Sciences and Environmental Technology (ATGM) has launched a new training session this academic year: on biorefinery.

The aim of the research is to see whether you can use biorefinery to make products out of waste. Second-year students are working on fruit peel, grass and hemp stalks, but also peanuts and algae. These are currently still being used on a limited scale and being cultivated specifically for this purpose with a view to the future.

Proteins
The students are researching usable components: for instance they are looking at which fruit peel contains the most proteins so that these can be used to make food. Another group of students is separating grass into a fibre and a protein concentration.

‘Exerting great pressure on the grass or the fruit peel with a press causes the juice and oil to flow out’, explains lecturer Aart van den Dool. The cells of the peel are then lysed, ‘opened up’, by freezing them and breaking them into pieces with force. The powder sample undergoes the extraction process, and the concentration is ultimately determined by a colour reaction: the darker blue the liquid, the higher the concentration.

‘The biodiversity in raw materials is so great that we achieve something new every day’

Sustainable paint
The juice and fibre from the used waste streams are employed in different ways. For instance the concentrated orange peel juice is used as an aroma in another group’s soap. The grass fibre can be used to make biobased clothing – although according to the students this needs to be developed further – and the grass juice can be used for sustainable paint.

‘The biodiversity in raw materials is so great that we achieve something new every day’, says Van den Dool. ‘The groups of students eventually draw up a financial balance sheet. They must then demonstrate in their pitches of the end results whether it is also a cost-effective method of biorefinery.’

See Facebook for photos of the students’ biorefinery research.