Digitally Programmable Manufacturing of Living Materials Grown from Biowaste.

Material manufacturing strategies that use little energy, valorize waste, and result in degradable products are urgently needed. Strategies that transform abundant biomass into functional materials form one approach to these emerging manufacturing techniques. From a biological standpoint, morphogenesis of biological tissues is a "manufacturing" mode without energy-intensive processes, large carbon footprints, and toxic wastes. Inspired by biological morphogenesis, we propose a manufacturing strategy by embedding living Saccharomyces cerevisiae (Baker's yeast) within a synthetic acrylic hydrogel matrix. By culturing the living materials in media derived from bread waste, encapsulated yeast cells can proliferate, resulting in a dramatic dry mass and volume increase of the whole living material. After growth, the final material is up to 96 wt % biomass and 590% larger in volume than the initial object. By digitally programming the cell viability through UV irradiation or photodynamic inactivation, the living materials can form complex user-defined relief surfaces or 3D objects during growth. Ultimately, the grown structures can also be designed to be degradable. The proposed living material manufacturing strategy cultured from biowaste may pave the way for future ecologically friendly manufacturing of materials.