Consider a process to recover an extracellular product expressed in bacterial cells. The total fermentation broth volume is $2000$ L$.$ The cell concentration in the broth is $150$ g L$-1,$ product concentration is $2$ g L$-1$ and the relevant impurities were measured at $0\mathrm{.}3$ g L$-1.$ The density of similar bacterial cells can be found in $[1].$A single stage experiment using an existing centrifuge $($Centrifuge C$-101$X$)$ showed that the process gives $85\%$ product yield with $95\%$ removal of cells. At least $3\mathrm{.}8$ kg is needed to meet product demand and the process duration should not take longer than $20$ hours to ensure product stability. Figure $1$ shows the predicted performance for a single stage run of C$-101$X$.$The CTO of the company also want to ensure that the process is sustainable and environment$-$ friendly. This is typically measured by the E factor, the ratio of kg waste$/$ kg product $[2].$ However, for early process steps within a bioprocess sequence, it may not reflect the actual waste of the process step as the waste steam may be recovered in further downstream steps. As a substitute, process mass intensity offers a different metric $($PMI $=$ total mass into the process $($kg$)/$ mass of product $($kg$))[3].$The following solutions $($a$)$ or $($b$)$ are proposed. Demonstrate how these solutions meet the product and process requirements described above.a$)$ Pre$-$diluting the feed by buffer and using the existing centrifuge in a single step. b$)$ Using the existing centrifuge and recovery more product by washing the sediment andre$-$centrifuging this.