L-Tyrosine (R&D Naturals)


White, powdered, nonessential amino acid.
Precursors and biosynthesis made in UK.
Biosynthesis & Extraction
Biosynthesized from Escherichia coli strain (derived from an L-phenylalanine).
Quality Control
Following start-up inspection, fermentation medium components, and DI water is batched into the fermentor and sterilized for 30 min. Once the contents have cooled down, 60% glucose feed solution is added using a peristaltic pump such that final concentration of glucose in the tank is 18–23 g/L. Once all prescribed operating parameters such as DO, pH, pressure, temperature, rpm, airflow are stabilized, the culture from the shake-flask is added to the fermentor following aseptic transfer protocols. The fermentor is sampled periodically for biomass growth (OD550) and residual glucose. Off-gas composition is monitored to ensure typical CER or OUR are obtained. After about 6–8 h of elapsed fermentation time (EFT) when the OD550 of the culture is within 8–10 or CER in the range of 35–55 mmol/L/h, the entire content of the seed fermentor that is typically between 7 and 8 kg is transferred to the primary 200 L production vessel. This transfer of seed inoculum is done under pressure using steam sterilized closed loop transfer lines. Physical separation of L-Tyrosine crystals from biomass using a decanter type centrifuge, based on the density difference between the solids is then utilized.