New aims have emerged to reduce the environmental impact of human activities including construction. The use of natural, local, recyclable, traditional building material as earth associated with an innovative manufacturing technique like 3d printing would achieve a sustainable architecture that promotes the notion of a low-carbon, zero-waste design for a successful circular economy. Although ancient earthen constructions have proven the longevity of raw earth as construction material, it is still considered as a non-standard building material due to its sensitivity to water, low mechanical resistance and the high tendency to crack during the drying phase as a result of shrinkage phenomenon. This paper introduces a new circular earth based biomaterial compatible with 3D printing. A biodesign approach was used to achieve better performance of material. Micro-fibers, obtained from laboratory cultivated bacterial cellulose (BC), were proposed as a reinforcer for the soil matrix with the aim of reducing shrinkage impacts and increasing material mechanical resistance. In this research, the impact of bacterial cellulose addition on rheological behavior and shrinkage of the raw earthen mixture has been defined and measured. A simple methodology has been proposed for the development of an extrudable stabilized earthen mixture compatible with the 3D printing technique by extrusion. Finally laboratory-scale printed samples have been carried out and mechanically tested.