*Article* **Multi-Organism Composites: Combined Growth Potential of Mycelium and Bacterial Cellulose**

**Aileen Hoenerloh \*, Dilan Ozkan and Jane Scott**

Hub for Biotechnology in the Built Environment, School of Architecture, Planning and Landscape, Newcastle University, Newcastle upon Tyne NE1 7RU, UK; d.ozkan2@ncl.ac.uk (D.O.); jane.scott@newcastle.ac.uk (J.S.) **\*** Correspondence: a.t.hoenerloh2@ncl.ac.uk

**Abstract:** The demand for sustainable materials derived from renewable resources has led to significant research exploring the performance and functionality of biomaterials such as mycelium and bacterial cellulose. Whilst the growing conditions and performance of individual biomaterials are understood, to achieve additional new and enhanced functionality, an understanding of how biomaterials can be used together as composites and hybrids is required. This paper investigates the compatibility of mycelium and bacterial cellulose as two biomaterials with different qualities for the development of a large-scale biohybrid structure, the *BioKnit* prototype. Their compatibility was tested through preliminary design experiments and a material tinkering approach. The findings demonstrate that under optimal conditions mycelium and bacterial cellulose can grow in each other's presence and create composites with an extensive array of functions. However, there is a need to develop further fabrication settings that help to maintain optimal growing conditions and nutrition levels, whilst eliminating problems such as contamination and competition during growth.

**Keywords:** mycelium; bacterial cellulose; biocompatibility; knitted fabric; material tinkering
