Fig. 2.

Summary of genetic optimization and scale-up results. (a) Promoter library screening. Individual colonies from the operon (red bars) and pseudooperon (gray bars) libraries were selected and evaluated to discover elite production strains. Data for samples producing 0 mg/L of norbaeocystin (11.5% of total colonies screened) are not shown. (b) Normalized production of operon library members for norbaeocystin and psilocybin pathways organized in order of increasing promoter strength: G6 (low) – T7 (high). Constructs for each operon promoter configuration were identified and screened providing evidence that the transcriptional optimization solution for the norbaeocystin pathway differed from that of the psilocybin pathway. (c) Effect of varying supplemental serine concentration in the initial fermentation media on strain performance in the bioreactor. (d) Metabolite and growth curve profiles for a representative norbaeocystin bioreactor fed-batch fermentation. Data shown for one replicate of the 0 g/L serine condition. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)