Principal Scientist, Process Development (Expression Systems)

Location: Norwood, Massachusetts, United States; 70% in-office work under a 70/30 model

Salary: $142,500–$256,500 per year, plus potential bonus, incentive compensation, or equity.

Company

hirify.global develops mRNA-based medicines, vaccines, delivery technologies, and manufacturing platforms for therapeutic and infectious-disease applications.

What you will do

• Lead host strain, vector, and expression-system strategy for E. coli production of recombinant enzymes, plasmids, and related biological materials.
• Design and execute screening cascades evaluating titer, yield, quality, genetic stability, robustness, and manufacturability.
• Develop and optimize small-scale and high-throughput workflows using shake flasks, deep-well plates, ambr systems, and other scale-down models.
• Evaluate promoters, ribosome-binding sites, copy number, plasmid architecture, induction systems, codon strategies, secretion, localization, and expression timing.
• Use design of experiments and data-driven methods to improve screening throughput, reproducibility, predictiveness, and translation to bioreactor performance.
• Partner with process development, analytical development, downstream purification, informatics, automation, and data science teams; prepare technical, CMC, and regulatory documentation.

Requirements

• PhD with 5+ years of relevant industry experience, MS with 10+ years, or BS with 12+ years in molecular biology, microbiology, biochemical engineering, biotechnology, synthetic biology, or a related discipline.
• Substantial industry experience with E. coli strain engineering, vector design, expression-system development, or microbial production screening.
• Hands-on experience developing microbial expression-screening workflows for recombinant proteins, enzymes, plasmids, or related biological products.
• Strong knowledge of E. coli genetics, physiology, metabolism, plasmid biology, expression regulation, and genetic stability.
• Experience connecting host, vector, and expression choices to titer, yield, quality, robustness, and manufacturability, and translating screening data into process-development decisions.
• Only U.S. persons who are citizens, permanent residents, asylees, or refugees are eligible because of U.S. export-control requirements; visa sponsorship for non-U.S. persons is not available.

Nice to have

• Experience with promoter or RBS libraries, plasmid copy-number optimization, induction tuning, codon strategies, secretion or localization, and protein solubility optimization.
• Knowledge of fermentation process development, downstream interfaces, and analytical methods for expression, identity, purity, activity, plasmid quality, and impurities.
• Experience with CMC documentation, technical reports, regulatory questions, or leading a small technical team.

Culture & Benefits

• In-person collaboration model with 70% of work conducted in the office.
• Healthcare coverage and voluntary benefit programs.
• Fitness, mindfulness, mental-health, family-planning, fertility, adoption, and surrogacy support.
• Paid vacation, volunteer days, sabbatical, global recharge days, and discretionary year-end shutdown.
• Savings and investment opportunities, plus location-specific benefits.