Associate Scientist: Protein Purification

San Francisco Bay Area - Union City, CA
Jun 17, 2021
Required Education
Masters Degree/MBA
Position Type
Full time


Celltheon Corporation is a contract research company located in the San Francisco Bay Area. We are dedicated to offering our clients a diverse range of technical expertise from molecular biology, cell culture, and generation of early stage pre-clinical material. Celltheon employees enjoy the benefit of having the opportunity to work in a diverse challenging and technical environment with a chance to learn and contribute in multiple areas, offering both personal and professional growth in a short time frame. Celltheon seeks talented, dedicated individuals to join its growing team. Celltheon offers a competitive salary and benefits program. If you desire a position in an active, collaborative scientific environment with the opportunity for professional growth and contribution, please apply on biospace.

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Associate Scientist Job Description

Celltheon is seeking an innovative, independent and motivated professional with experience and expertise in downstream development. The successful candidate will join a team of scientists focused in protein purification (chromatography), protein characterization, analytics, and method development to analyze recombinant proteins during various stages of cell line development, process development and scale up. This candidate will report to Celltheon's Director of Purification. An ideal candidate has experience in development of purification methods and analytical methods. Some of the responsibilities include:

• Protein purification: Develop 1-3 column custom purification process to purify proteins produced from mammalian cells (i.e: mAbs, Fabs, Fcfusions, bi-specifics, small proteins, etc).

• Unit operations: Develop bench scale purification techniques including harvesting, filtration, chromatography (SEC, ProA, ProG, ProL, CEX, AEX, HIC, IMAC, Mixed modes).

• Analytics: Carry out assays of process intermediate samples like ProA HPLC for titer, RP-HPLC, SEC HPLC, CEX HPLC, N-Glycan analysis, Spent Media Analysis by HPLC, Western blotting, SDS-PAGE, pH, conductivity adjustment, Host Cell Protein (Cygnus Assay), LAL Endotoxin assay, Bradford and BCA assays. ELISA’s and cell based assays in 96 well formats.

• Manufacturing: Scale-up chromatographic processes and other unit operations developed at bench-scale for pilot scale purification to support manufacturing operations (equipment cleaning, chromatography processing, tangential flow filtration, UF/DF, analytics, etc.).

• Maintenance: Maintain purification and analytic equipment such as HPLC and FPLC regular maintenance (i.e: initiate cleaning procedures between system change overs).

• Technical expertise: Exercise judgment within defined practices and policies to determine appropriate action and understand technical literature for troubleshooting. Ability to solve routine scientific problems with deductive reasoning. Scientific understanding of the industry and a general knowledge of the products and technologies needed to develop processes.

• Communication: Regularly gives written status updates on assigned tasks. Interprets and effectively communicates scientific findings / results in one-on-one and/or group discussions and summarize results for presentations.

• Data maintenance and interpretation: Collects and compiles data and records in laboratory notebooks, ensuring they are consistently updated, audited, and well maintained. Maintains batch records and working templates for raw data and writes SOPs regularly. 

• Performance and Management: Ability to follow written and verbal instructions in the performance of experiments, assays, and method development procedures. Ability to learn quickly, pay attention to detail, prioritize assigned tasks and effectively manages time for completion to meet deadlines.


• Master’s in Biotechnology, Bioprocessing, Bioscience or a related field plus 3-4 years of industry experience or equivalent PhD/ Post-Doc experience

• Protein purification and analysis experience, mainly hands-on experience with FPLC and HPLC is desired.

• Understanding of GxP compliance is preferred.

• Strong working knowledge of Microsoft suite of software (Word, Excel, Powerpoint, Access)

• Good verbal and written communication skills including report writing.

• Ability and desire to be a good team-player of a project team.