Recombinant Proteins

List Biological Laboratories is a premier GMP Contract Manufacturing Organization with an extensive history of working with recombinant protein expression in bacterial systems. List has manufactured recombinant proteins of bacterial or mammalian origin to support our clients’ projects from Research and Development through Phase I and Phase II clinical trials. With your protein of interest in a suitable expression system, your process is optimized and can be scaled up to facilitate large scale production of up to 100 L of culture. Target proteins are isolated from the cell lysate soluble fractions or from inclusion bodies to yield high purity recombinant proteins that can be further processed to remove affinity tags per client request prior to product packaging.

Background on Recombinant Proteins

Protein expression in Escherichia coli has been the most widely utilized means of producing recombinant proteins for over twenty years. E. coli is a well-understood host organism that offers, straightforward genetic modification and a rapid growth profile. Selection of the optimal expression vector and bacterial growth/induction conditions ensures high-level production of target proteins from viral, prokaryotic, and eukaryotic sources. The inclusion of affinity tags such as polyhistidine (6His), glutathione S-transferase (GST), or maltose-binding protein (MBP) significantly increases the yield and purity of recombinant proteins, and they can be left intact or easily removed depending on the intended use of the product. Recombinant proteins have achieved profound success in the biotechnology and pharmaceutical industries, and have been used in the production of vaccines and therapeutics to treat a wide variety of conditions.

Process Development

List Labs is flexible to meet the unique needs of recombinant protein client projects. We offer the following development services to establish a reproducible and robust process:

  • Cell Bank Preservation
  • Media Optimization
  • Fermentation Development
  • Protein Expression Optimization
  • Purification Development
  • Lyophilization Development
  • Analytical Method Development
  • Process Scale-Up

Initially, a technical transfer is desired to acquire familiarity with the recombinant protein expression system and replicate client data and results. Small scale work is designed to support a seamless transition to a process geared towards large-scale cGMP manufacturing. Optimization of media and fermentation conditions are designed to increase the yield of product and to replace any animal-derived components with non-animal origin (NAO) raw materials for cGMP manufacturing. Various fermentation and fed-batch fermentation process parameters can be evaluated in parallel in a scalable model to quickly establish a reliable growth process. Purification processes are similarly evaluated in parallel to meet your project goals in a timely manner.

To support process development and future process validation, clients are recommended to provide in-process tests to aid in the evaluation of each step’s success, as well as to assess the final product. Analytical method development will be tailored to the desired product as well as generally applicable analysis described in the USP. These tests may include product activity, antigenicity, endotoxin content, moisture, water activity, and osmolality. List Labs can apply our considerable experience with suitability testing to develop the necessary analytics specific to your project.


Our highly skilled team has extensive experience with cGMP manufacturing of recombinant protein products from E. coli. Our expertly designed manufacturing facility provides containment in ISO7 or ISO8 suites, and multiple production suites allowing parallel cGMP manufacturing activities to streamline project timelines. List Labs has several large-scale options for the production of recombinant proteins including 100 L stainless steel vessels with validated cleaning procedures and 40 L disposable bioreactors. Downstream production capabilities include Tangential Flow Filtration units up to 100 L in scale, three ÄKTA FPLCs for the purification of recombinant proteins, and three lyophilizers with a 5 tray, or 3000 x 2 mL vials, capacity each. List Labs also has experience with sieving and powder filling into different packaging modalities upon client request. We offer the following manufacturing services:

  • Research Cell Bank Production
  • cGMP Master and Working Cell Bank Production
  • cGMP Drug Substance Production
  • cGMP Drug Product Production
  • Formulation and Lyophilization Services
  • Sieving and Dry Filling Services
  • Liquid Filling Services
  • Custom Packaging Services


List Labs staff has over 25 years’ experience manufacturing bacterial based novel drug substances and products.  List maintains several Drug Master Files with FDA and Health Canada and provides support to clients for IND filings.  As required by the State of California, List Labs maintains a current Drug Manufacturing License and CDC Select Agent registration enabling us to produce drug substance and drug products for our clients.

List Labs has manufactured a variety of bacterial toxins and proteins, live biotherapeutics products (LBS), and polysaccharides for our clients.  cGMP manufacturing has included both drug substance and drug products for Phase I and II clinical trials.

List complies with 21 CFR 210, 211, as well as ICH and Regulatory Guidelines, as applicable, for early-stage Investigational New Drugs (IND) and Investigational Medicinal Products (IMP).

For more information, see our GMP services page.

QC Analytical Testing

The majority of QC testing for recombinant protein products can be developed and executed by List Labs, creating a seamless full-service offering for your project requirements. Typically, testing provided by List Labs includes:

  • Product Identity
  • Product Purity
  • Product Activity
  • Endotoxin Content
  • Moisture Analysis
  • Water Activity
  • Host Cell Protein Content
  • Residual DNA

For more information about our QC analytical testing, follow the icon below.


Equipment in our facility for manufacturing recombinant protein products include incubators, disposable bioreactors, stainless steel fermenters, tangential flow filtration systems, FPLC systems, lyophilizers, dry chambers, and fill equipment. For more information about our available equipment, click the icon below.