Fig. 9. Different methodologies to determine the producer strain within the co-cultures. (A) Using structural similarity of compounds generated in the monoculture and the co-culture to determine the producer strain. If the compound of interest is structurally similar to the chemical classes produced by of one of the co-cultured strains, then it may be deduced that the strain that produces similar compounds is the producer. (B) Using the location of where the compound is found to determine the producer strain. The use of in situ analysis (e.g., droplet probe, MALDI, DESI, etc.) can elucidate the spatial location of the compound across the co-culture. The location can then indicate the producer strain. (C) Pairing the original co-cultured strains with different strains to identify the producer strain. Here, the strains from the original co-culture are paired with different fungal strains. The goal is to identify which co-cultured strain can produce the compound of interest. Theoretically one of the previously co-cultured strains could then produce the same compound during a different pairing, indicating that it was the original producer. (D) Doping the media with ¹³C labeled glucose and identifying which strain was able to incorporate the ¹³C label into the compound of interest. The liquid co-culture is separated back into the respective monocultures and then subsequently ¹³C labeled glucose media is added to those monocultures. The goal of this is to see which strain was able to uptake the ¹³C labeled glucose and produce the ¹³C labeled compound of interest, indicating which strain is the producer. (E) Matching a proposed Biosynthetic Gene Cluster (BGC) of the compound to the BGC's found within the strains. Using genome mining, if the BGC that encodes for the compound of interest can be identified in one of the co-cultured strains and not the other, then the strain that contains the BGC is likely the producer strain.