Cellulose is the most abundant bio-polymer on earth. Cellulose fibres, such as the one extracted form cotton or woodpulp, have been used by humankind for hundreds of years to make textiles and paper. Here we show how, by engineering light matter-interaction, we can optimise light scattering using exclusively cellulose nanocrystals. The produced material is sustainable, biocompatible and, when compared to ordinary microfibre-based paper, it shows enhanced scattering strength (x4) yielding a transport mean free path as low as 3.5 um in the visible light range. The experimental results are in a good agreement with the theoretical predictions obtained with a diffusive model for light propagation.