Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Biotech / Medical : Ciphergen Biosystems(CIPH): -- Ignore unavailable to you. Want to Upgrade?

To: tuck who wrote (126)	5/29/2003 1:31:37 PM
From: tuck	Read Replies (1) \| Respond to of 510

Someone outside Ciphergen finally uses the technology to speed optimization of production chromatography: >>J Chromatogr B Analyt Technol Biomed Life Sci 2003 Jun Endostatin capture from Pichia pastoris culture in a fluidized bed. From on-chip process optimization to application. Shiloach J, Santambien P, Trinh L, Schapman A, Boschetti E. Biotechnology Unit, NIDDK, Bethesda, MD, USA One of the characteristics of the methylothrophic yeast Pichia pastoris is its ability to grow to a very high cell density. Biomass concentrations of 300-400 g wet mass/l are common. It is therefore obvious that the recovery processes of extracellular proteins from this microorganism should take into account the effect of high biomass content. Separation by filtration and/or centrifugation is possible but these steps are cumbersome and can affect the protein recovery. The use of fluidized beds is attractive proteins capture option since it eliminates the biomass while capturing the desired protein. Zirconia-based resins possess unique properties which make them appropriate for processing high biomass concentrations in an expanded bed mode. The beads are particularly heavy (density is 3.2 g/ml) and small (75 &mgr;m) and therefore can accommodate high fluidization velocity and high mass transport. Specific operating conditions for effective capture of expressed protein have to be determined. This determination is generally time consuming and requires relatively large amount of feedstock for the lab trials. To avoid multiple chromatographic trials in columns, optimal conditions of adsorption and elution were determined by ProteinChip technology coupled with mass spectrometry. This technology involves flat chip surfaces functionalized as chromatographic beads where it is possible to adsorb and desorb proteins. Four different functional groups (strong anion-exchange, weak cation-exchange, hydrophobic and metal chelate) were tested and the retained proteins were analyzed directly by mass spectrometry. The weak cation-exchange group was chosen for further work. The Zirconia-based weak cation-exchange sorbent (CM HyperZ) was evaluated for binding capacity in a packed column and then for capturing endostatin from crude feed stock. Based on the previously determined conditions; 45 l of culture containing approximately 15 kg of biomass (wet mass) and 3 g endostatin were applied on an expanded bed at a flow-rate of 535 cm/h, yielding 80% of the endostatin and removing approximately 80% of foreign proteins.<< Cheers, Tuck