Base Case Scenario Analysis
We evaluated the impact of process parameter variation on the model facility production costs, univariately investigating 1) rrBChE expression level in rice biomass, 2) the proportion of culture harvested per cycle of semicontinuous operation, and 3) the dynamic binding capacity of the Hupresin in the affinity chromatography procedure. The facility model was re-designed (e.g. resized) for each parameter variation scenario to maintain the same production level and final product consistency with the base case, while all other parameters were fixed for the analysis. The ranges of the process parameter variation tested in the analyses were determined using working process knowledge. The results of the scenario analyses are shown in Figure 4.
Cost of goods sold (COGS) is most sensitive to expression level variation within the selected parameter ranges, as shown in Figure 4. In each of the analyses there is a clear display of COGS decreasing monotonically with increasing parameter value with diminishing returns. As an illustrative example, the COGS decreases by 46% ($549/g rrBChE reduction) when increasing expression from 100 to 200 mg rrBChE/kg FW, but a larger increase from 200 to 500 mg rrBChE/kg FW is required for a comparable 49% reduction in COGS from that point (at $325/g rrBChE reduction).