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Sr. Scientist / Scientist, Cell Culture Process Development

As member of the CMC group, the Sr Scientist/Scientist will contribute to the upstream process development to advance Janux pipeline from research through clinical development towards commercialization. This position requires hands-on execution of strain screening, media development and process optimization to establish robust and scalable cell culture processes. The successful candidate will also be responsible and serve as SME for tech transfer activities to Contract Development and Manufacturing Organizations (CDMO) for clinical manufacturing.


  • Responsible for upstream process development.
  • Evaluate and implement technologies to improve process productivity and robustness.
  • Design and perform DOE experiments to identify and establish upstream operating and performance parameters.
  • Media preparation, culture inoculation, expansion, and harvest of bioreactors.
  • Responsible for operation and preventive maintenance of laboratory equipment like bioreactors and chemical analyzers.
  • Write operational procedures/batch records, process descriptions and technical documents to support process development at CDMOs.
  • Maintain detailed records of all experiments performed.
  • Effectively analyze, organize, and communicate experimental results to colleagues and senior leadership.
  • Train and mentor junior members of the team and collaborates across functional areas.
  • Travel: up to 15% (domestic and/or international) may be required.

Required Skills/Qualifications:

  • Extensive knowledge in cell culture media development and optimization of process parameters using benchtop-scale bioreactors is highly preferred.
  • Experience with using design of experiments (DOE) software to guide process development.
  • Experience with batch and fed-batch cell culture
  • Tech transfer experience is highly desirable.
  • Working knowledge of transfection methods and selection markers for recombinant protein expression in mammalian cells is a plus.
  • Familiarity with downstream processing and purification of antibodies is preferred.
  • Strong analytical skills and ability to work in a highly collaborative environment.
  • Excellent written and oral communication skills.


  • Ph.D. in Cell and Molecular Biology, Biotechnology, Bioengineering or a related discipline + 3 – 6 years of postdoctoral experience or a BS/M.S. + 8 – 11 years of industry experience in biologic upstream process development.


Janux offers a competitive compensation with stock options in addition to a comprehensive benefits package consisting of medical, dental, vision, and supplemental disability insurance.

Job Type: Full-time


  • 401K (3% employer matching)
  • Medical insurance
  • Dental insurance
  • Vision insurance
  • Supplemental disability insurance plans
  • Flexible schedule
  • Life insurance
  • Flexible vacation
  • Incentive stock option plan


Monday to Friday On-Site (La Jolla, CA)

COVID-19 Vaccination required

Janux requires all new hires to be fully vaccinated for COVID-19 prior to the first date of employment. As required by applicable law, Janux will consider requests for Reasonable Accommodations.

Work authorization:

  • United States (Required)


Janux Therapeutics, Inc. is an equal opportunity employer that is committed to providing a work environment free of harassment and discrimination based upon a protected category, as well as an environment free from retaliation for protected activity.