Surface Pitting on Nanofibrous Matrix as an Ultra- Sensitive Indicator for Enzymatic Hydrolysis of Crystalline Cellulose

Assaying enzymatic degradation of the water-insoluble substrate such as cellulose and synthetic polymers has remained technically challenging, primarily because only the surface of the substrate is accessible to the enzymes and the reaction proceeds very slowly compared with those of water-soluble substrates. Here we show an ultra-sensitive and semi-quantitative assay for enzymatic hydrolysis of cellulose. By combining nanofibrous matrices with piezo-driven inkjet printing and optical profilometry, enzymatic hydrolysis of less than 1 nanogram of crystalline cellulose was successfully quantified. Unprecedented genetic diversity of cellulase was revealed when the same principle was applied for elucidating microbial degradation of cellulose in the deep sea. This work demonstrates that truly interdisciplinary efforts, encompassing diverse disciplines from nanotechnology to microbiology, are crucial to address scientific and technological problems towards sustainability.