Bioprocess Engineer

The Opportunity (Full-time, San Francisco)

We are seeking a Bioprocess Engineer to lead the downstream processing and stabilization of live probiotic microbes, with primary ownership of microbial drying, shelf life performance, and scale up manufacturability. While this role is downstream-led, given the small size of our team, it also encompasses upstream microbial cultivation and harvest.

You will own the conversion of aerobic bacterial cultures into stable, scalable dry formats, applying a first principles understanding of drying, stabilization, and unit operations to deliver reproducible performance at pilot manufacturing scale. You will operate and refine existing SOPs, develop new ones as needed, select and run equipment directly, and be accountable for real production output, shelf life, and scalability. This is a broad, hands-on manufacturing role that overlaps meaningfully with applied process development.

This role reports to our Head of Manufacturing.

Required Qualifications

✔️ Microbial bioprocessing — 4+ years of hands-on experience cultivating and processing aerobic microbes, including media preparation, shaker flasks, and biomass harvest.

✔️ Downstream processing and desiccation — 6+ years of experience drying biological materials, with direct hands-on operation of desiccation systems used for live microbes.

✔️ Process rigor and documentation — experience operating in cGMP-like environments with strong cleanliness standards, SOPs, batch records, and traceability.

✔️ Independent operator mindset — ability to select, procure, set up, troubleshoot, and operate bioprocessing and drying equipment with minimal supervision.

✔️ Full on-site availability — based in or willing to relocate to the San Francisco Bay Area.

✔️ Authorized to work in the U.S. — Visa sponsorship is not available for this role.

Highly Desirable Experience

✔️ Bench-scale microbial fermentation — hands-on experience running and optimizing bench-scale fermentations for aerobic bacteria, including media selection, growth monitoring, harvest timing, and consistency across batches. Practical understanding of how upstream growth conditions impact downstream drying performance, including cell health, stress tolerance, and survival through desiccation.

✔️ Contamination management and response — experience identifying, containing, documenting, and escalating contamination events in microbial processes; prioritizing system integrity and long-term process health over salvaging individual batches; and supporting root cause analysis and corrective actions to prevent recurrence.

✔️ Microbial spray drying — direct experience spray drying live microbes or other viability-sensitive biological materials.

✔️ Lyophilization expertise — direct experience executing and iteratively optimizing lyophilization processes, with a first principles understanding of cycle parameters, excipient systems, and biological failure modes impacting viability and shelf life.

✔️ Downstream finishing — experience blending dried biological materials with excipients and operating finishing equipment such as tablet presses.

✔️ Process scale-up — translating bench-scale workflows into higher-throughput or more scalable manufacturing processes.

Transparent Compensation

✔️ Base salary — $130,000 annual salary.

✔️ Equity — meaningful equity package as a core component of total compensation.

✔️ Benefits — comprehensive health, dental, and vision insurance.

✔️ Retirement — 401(k) plan with a 6% employer match.