Sunflower Therapeutics Demonstrates Perfusion Fermentation of Bacteria in the Daisy Petal®
A new application note shows the Daisy Petal® perfusion bioreactor sustaining an eightfold increase in biomass and a tenfold longer operating lifetime than a batch process — this time with a bacterial host.
Sunflower Therapeutics has published an application note demonstrating perfusion fermentation of a bacterial expression host in its Daisy Petal® Perfusion Bioreactor System. Working with Opera Bioscience, the team cultivated a gram-negative bacterial strain engineered to secrete a reagent protein through its endogenous type III secretion system (T3SS).
The fermentation ran at a 1 L working volume in STx002, Sunflower's chemically defined growth media, inoculated at an initial cell density of 0.05 OD600/mL and held at an average perfusion rate of 2.5 vessel volumes per day. The HelianthOS™ operating system controlled the reactor hardware and maintained process setpoints — reactor volume, temperature at 37°C, pH and dissolved oxygen — then initiated an automated shutdown once the target fermentation time of 102 hours was reached.
Key results
Eightfold higher biomass than an established batch process cultivating the same strain.
Tenfold longer operating lifetime, extending the window for continuous harvest of the secreted product.
Secreted protein recovered directly from the cell-free perfusate through the in-vessel cell retention device (CRD), with no additional processing prior to SDS-PAGE analysis.
By continuously supplying fresh nutrients and flushing out waste byproducts, the system avoids the premature decline in cell state typical of batch methods, while the in-vessel CRD keeps biomass inside the controlled reactor environment. That combination collapses cultivation and harvest into a single unit operation for bioprocesses generating secreted products.
Building on Sunflower's earlier demonstrations with yeast and fungal hosts, the results add bacteria to the platform's catalog of compatible expression systems and support the case for the Daisy Petal® as a host-agnostic solution for continuous microbial bioprocessing.