Mechanical Engineer, Microbial Fermentation (Contract)

Job Summary:

The Chemical Engineer applies transport and reaction engineering to our E. coli fermentation and protein manufacturing processes. You will define and verify the mixing, oxygen-transfer, heat-removal and gas-handling performance that supports high-density cultures and strong protein expression, and you will build the scale relationships that let results transfer reliably between vessels. You will work closely with others on equipment design and on control strategies and run execution.

This role joins a small, hands-on engineering group that supports protein manufacturing. The team runs and improves microbial fermentation at laboratory, pilot and production scale, with automated control of pH, temperature, pressure, dissolved oxygen and feeding, and works with the scientists who carry the product through harvest, purification and release.

Engineers in this group take on a broad mix of work: designing and improving equipment, developing mixing, aeration and control strategies, scaling processes between vessels, and writing the procedures that keep every batch consistent. You will work alongside mechanical, chemical and process engineers as well as R&D and manufacturing staff.

Join us in making a meaningful impact!

Essential Duties and Responsibilities

Mixing and mass transfer

• Establish targets for oxygen transfer (kLa), oxygen uptake rate, mixing time, power per volume, tip speed and shear that support high-density E. coli cultures.
• Evaluate impeller, baffle and sparger configurations, using correlations, CFD and experimental data.
• Design and run characterization studies such as kLa measurement, mixing-time studies, gas hold-up and foaming behavior.

Aeration, gas handling and heat transfer

• Develop aeration and oxygen-enrichment strategies, including air and oxygen blending, flow ranges, back-pressure and off-gas handling.
• Define safe practices and design limits for oxygen-enriched operation together with the team.
• Size heat-transfer capacity to remove metabolic heat during peak growth and maintain tight temperature control.

Scale-up and process chemistry

• Build scale-down and scale-up models that link laboratory, pilot and production fermentation.
• Support media and feed formulation, including carbon and nitrogen sources, trace elements, antifoam and pH titrants, and assess material compatibility and cleaning chemistry.
• Analyze run data (dissolved oxygen, pH, off-gas, optical density, protein titer) to identify transport or chemistry limitations and recommend changes.

Documentation and support

• Write technical reports, design calculations and test protocols that support equipment decisions and scale-up.
• Support troubleshooting of production fermentations, particularly oxygen limitation, foaming and temperature control issues.

Education and Experience:

• Bachelor's degree in Chemical Engineering or a closely related field
• Strong grounding in transport phenomena, mass and heat transfer, fluid mechanics and reactor design.
• Experience designing experiments and analyzing data quantitatively (Python, MATLAB, JMP or similar).
• Ability to translate engineering calculations into clear requirements for a multidisciplinary team.

Preferred

• Hands-on experience with microbial fermentation, ideally E. coli fed-batch processes for recombinant protein.
• Experience measuring kLa and mixing time and applying scale-up and scale-down principles.
• Familiarity with CFD for stirred tanks and gas-liquid systems.
• Knowledge of oxygen-enrichment safety and off-gas analysis.
• Exposure to downstream protein processing such as cell disruption, clarification and chromatography.

What Success Looks Like

• Within 30 days: documented mixing, oxygen-transfer and heat-transfer performance for our current fermentation vessels.
• Within 90 days: characterization studies completed and recommendations implemented that improve culture performance or consistency.
• Within 6 months: a validated scale model that predicts how process changes carry between laboratory, pilot and production scale.

Working Conditions

This is a hands-on, lab and plant-floor role. The work involves standing for extended periods, lifting equipment and media up to about 25 kg, and working around pressurized gases (including oxygen), rotating equipment, autoclaves and biological materials handled at BSL-1. Long fermentation runs occasionally require off-hours monitoring or extended days, planned in advance with the team.

About Us:

Since its inception in 1994, Zymo Research has been proudly serving the scientific community by providing innovative, reliable, and high-quality research tools and products. Whether it's DNA, RNA, epigenetics, microbiomics, protein, or yeast-based research, our philosophy remains the same: To provide the highest quality products in the industry while ensuring they are both simple to use and reliable in their performance.

Recognized as a Top Workplace by the Orange County Register in 2021, 2022, and named a Top Workplace USA in 2023, Zymo Research continues to be a vibrant community where employees thrive, feel connected, and are inspired by their work. If you are passionate about contributing to scientific advancement and want to be part of an exceptional team in a dynamic, growing company, we'd love to hear from you!

Compensation, Benefits, and Perks:                                 

The estimated base compensation range for this position is $75,000 - $115,000 per annum at the time of posting. Actual compensation details will be provided in writing at the time of offer, if applicable, and is based on several factors we believe fairly and accurately impact compensation, including geographic location, experience, knowledge, skills, abilities, and other job permitted factors.

Zymo Research also offers competitive benefits and perks including:

• Medical, Dental, Vision, and Life Insurance Coverages
• EAP Sessions
• Vacation Time plus Company Holidays
• Paid Sick Leave
• Generous 401(K) with matching 
• Employee Referral Bonus
• Complimentary fruit, snacks, and beverages
• Complimentary catered lunches on Thursdays 
• Complimentary EV Charging 
• Cell phone stipend

Equal Employment Opportunity Employer:

Zymo Research welcomes candidates of all backgrounds. These include sex, age, color, race, religion, marital status, national origin, ancestry, sexual orientation, gender, gender identity, gender expression, physical & mental disability, medical condition, genetic information, military and veteran status, or any other protected status as defined by federal, state, or local law.

Location:

Onsite – Zymo Research – 2961 Dow Ave, Tustin, CA, 92780

Disclaimer: At Zymo, we take the integrity of our hiring process seriously. Please be aware of fraudulent recruitment activities that may use our name to deceive job seekers. We will never ask for payment, sensitive personal information, or financial details during the recruitment process.

All legitimate communications will come from an official Zymo or TriNet Hiring email address. If you are contacted by anyone claiming to represent us using a free email service (e.g., Gmail, Yahoo, Hotmail) or asking for payment, please treat this as fraudulent and report it immediately to

careers@zymoresearch.com