High strength kami-ito yarns from microbial cellulose biofilms

We develop high-strength, sustainable yarns from microbial biofilms with minimal processing and chemical use. Inspired by the Japanese "kami-ito" () technique for creating yarns from paper, we introduce an eco-friendly alternative to cotton and industrially-produced man-made cellulose fibers using a microbial cellulose source. We culture and dye bacterial cellulose biofilms to produce yarns with tensile strengths of up to 200 MPa (55 MPa in the wet state). These bacterial cellulose (BC) yarns exhibit significant stretchability, with elongation reaching 23 % in dry condition, which is a remarkable improvement when considering the stiffness of typical man-made cellulose filaments and dried BC films. The BC yarns are shown to absorb up to 24 % water at 100 % relative humidity, comparable to natural fibers like hemp and flax. Our findings further underscore a multidisciplinary exploration that integrates biology, art, and design to develop durable, dyeable, and environmentally sustainable textile yarns.