The use of co-culturing in solid substrate cultivation and possible solutions to scientific challenges

This perspective systematically summarizes the use of solid substrate co-cultures in agriculture, food, plant, and industrial biotechnology applications. The summarization is organized by organism, i.e. fungus, bacteria, yeast and then co-cultivation of either two or three organisms. Generally, in solid substrate co-culture, the organisms synergistically penetrate and degrade the solid substrate, thereby increasing product yield and productivity over a monoculture. Efforts to increase co-culture performance include optimizing process parameters (pH, temperature, moisture, and oxygen demand) and defining the acceptable types of substrate. Scientific challenges exist in understanding the interactions between microbial stains, such as viability, suite of products, and bio-transformations. The perspective details possible solutions to these challenges and highlights future research directions for co-cultures using either solid or liquid fermentation.