Fungal living materials and the application of bacteria-fungi interaction on regulating mycelial growth: A review

Abstract

To address the environmental challenges posed by the linear economy of "produce, use, and dispose," various industries are transitioning toward bio-based and circular economy strategies. In this context, mycelium materials have emerged as a promising class of circular and sustainable materials, gaining significant research interest and commercialization potential across construction, packaging, and fashion sectors. The asexual growth of fungal mycelium offers an energy-efficient biomanufacturing method, where the mycelium colonizes and decomposes organic substrates, assembling into extensive networks that can be tailored to produce either dense, flexible mycelium-based leather-like materials or lightweight, insulating, soundproof, and fire-resistant composites to meet diverse application needs. At the end of their lifecycle, these materials are fully biodegradable, embodying a cradle-to-cradle recycling model. As such, they are widely recognized as sustainable alternatives to traditional energy-intensive building materials, plastics, textiles, and leather. However, current production processes involve heat treatment and drying after typically several weeks of growth, which kills the living fungal organisms. This practice inevitably limits the inherent biological functionalities of fungi, such as self-healing, self-regeneration, and environmental sensing and response. Recent research has increasingly explored fungi as promising microbial platforms for the development of Engineered Living Materials (ELMs). This review broadens the perspective on the use of filamentous fungi for ELM production by summarizing significant advancements and pioneering efforts in the field. The potential of fungal ELMs for the development of biosensors, smart wearable devices, robotic skins, intelligent self-cleaning surfaces, and self-healing materials is highlighted. Additionally, the ability of fungal mycelium materials to facilitate the in situ production of large-scale, living comstruction materials is emphasized, offering promising prospects for the growing field of engineered living materials. However, limitations in the genetic editing of filamentous fungi have been identified in current fungal ELM research. In response, the discussion then shifts to the potential of using engineered bacteria to regulate mycelium growth and functionalize mycelium materials, presenting a viable new strategy for the production of multifunctional, large-scale fungal ELMs. Finally, future research opportunities and challenges in this emerging field are outlined, aiming to inspire further innovation and exploration in the development of fungal-based ELMs.