  The global increase in materials consumption calls for innovative materials,
with tailored performance and multi-functionality, that are environmentally
sustainable. Composites from renewable resources offer solutions to fulfil
these demands but have so far been dominated by hybrid petrochemicals-based
matrixes reinforced by natural fillers. Here, we present biological matrix
composites with properties comparable to wood and commercial polymers. The
biocomposites are obtained from cultured, undifferentiated plant cells,
dehydrated and compressed under controlled conditions, forming a lamellar
microstructure. Their stiffness and strength surpass that of commercial
plastics of similar density, like polystyrene, and low-density polyethylene,
while being entirely biodegradable. The properties can be further tuned varying
the fabrication process. For example, filler particles can be integrated during
fabrication, to vary the mechanical response or introduce new functionalities.
