In the field of leather-working, mycelium-based options have emerged as feasible substitutes for commercial applications, given their robustness and versatility. However, pure mycelium skins cannot reach optimal performance in terms of strength and durability. Thus, post-processing with crosslinking additives has become a suitable approach to improve material properties, despite limitations with regards to uniform distribution and synthetic compound use. In this framework, bacterial cell factories, capable of interacting with mycelium and producing biobased additives (bioadditives), would introduce a novel post-processing approach which tackles current drawbacks. Therefore, our objective is to develop a cocultivation strategy to improve the distribution of additive-producing bacteria between mycelium hyphae. To achieve this, bacterial cells are equipped with the ability to selectively bind to mycelial hyphae, generating a stable interaction between the mycelium and the cell factory, and subsequently engineered to produce promising bioadditives in situ. Lastly, an optimized coculture setup is being developed to produce mycelium leather with improved strength and durability.