Scientists from the Polytechnic Institute of Viseu in Portugal have discovered a way to make use of spent coffee grounds, a common byproduct in the consumption of coffee. The study, which was published in the Journal of International Scientific Publications, looked at the possibilities of isolating holocellulose from the by-product, in order to be used for products such as cellulosic pulp or type I cellulose.

• To test the spent coffee grounds, the samplings were divided into three fractions, which was composed of > 40 Mesh (> 0.425 mm), from 40 to 60 Mesh (0.425 to 0.250 mm) and 60-80 Mesh (0.250 to 0.180 mm) and < 80 Mesh (< 0.180 mm). The fractions had been dried using an oven at a temperature of 100 degrees Celsius before they were tested.
• The Kürscher and Hoffer method was used to isolate cellulose from coffee grounds. This was identified using X-ray diffraction. In addition, holocellulose was prepared from coffee grounds using two types of oxidative cooking: with alkaline hydrogen peroxide and with peracetic acid.
• The study revealed that spent coffee grounds is a lignocellulose material, with its major component being tannins. In addition, hemicellulose and cellulose were also discovered to comprise spent coffee grounds.
• The cellulose derived from the coffee grounds was noted to be cellulose I (native cellulose) that had a high degree of crystallinity.
• The oxidative treatment of the grounds also yielded holocellulose, which was made up of cellulose and xylans.

Researchers concluded that cellulose can be isolated from spent coffee grounds.

Find the full text of the study at this link.

Journal Reference:

Cruz-Lopez L., Domingos I., Ferreira J., Esteves B. A NEW WAY OF USING SPENT COFFEE GROUND. Journal of International Scientific Publications. 2017;5:85–93.