23 Jan The complex process of manufacturing methionine and Bacterial Ingenious
The complex process of manufacturing methionine and Bacterial Ingenious
Methionine is an essential amino acid in humans. As the substrate for other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical role in the metabolism and health of many species, including humans, poultry and all the farm animals
As an essential amino acid, methionine is not synthesized de novo in humans and other animals, which must ingest methionine or methionine-containing proteins. In plants and microorganisms, methionine biosynthesis belongs to the aspartate family, along with threonine and lysine (via diaminopimelate, but not via α-aminoadipate). The main backbone is derived from aspartic acid, while the sulfur may come from cysteine, methanethiol, or hydrogen sulfide
Chemical formula: C5H11NO2S
Appearance: White crystalline powder
Density: 1.340 g/cm3
Melting point: 281 °C (538 °F; 554 K) decomposes
Solubility in water: Soluble
Ball-and-stick model _ Space-filling model
Process of manufacturing
Companies harness nature to make feed amino acids via fermentation, but the presence of a Sulphur atom has thwarted a similar approach for methionine. Instead, it is made via a complex chemical synthesis involving hard-to-handle raw materials such as methyl mercaptan, propylene and hydrogen cyanide..
Methionine (Met) is defined as an essential -amino acid, because it cannot be synthesized by mammals and has to be ingested through food. As the methionine content in raw plant materials is insufficient, synthetic methionine complements must be added to animal feed. In animal diets it is the second limiting amino acid after lysine and in poultry it is even the first limiting one. Where lysine can be produced by bacteria via a relatively simple fermentation process, methionine has to be constructed chemically from mineral and organic derived compounds. Together with cysteine, methionine is one of two Sulphur-containing proteinogenic amino acids. Methionine is an intermediate in the biosynthesis of cysteine, carnitine, taurine, lecithin, phosphatidylcholine, and other phospholipids. Non-essential L-cysteine can only be synthesized by the body from L-methionine, and when methionine is in short supply cysteine will become an essential amino acid too.
Massive and secured logistics
The production process of methionine requires six main raw materials: Sulphur, methanol, ammonia, propylene, sulphuric acid and energy (gas – CH4). The long chain of process steps is limited by the weakest step. Raw materials and intermediates have to be available in quantity and on time, since the plant is running 24/7 every day of the year. This can be complicated since raw material storage capacities are limited; meaning that logistics are a big issue, as well as maintenance of the plant.
Propylene is the main strategic raw material for methionine production. The two main sources of propylene are a byproduct from the steam cracking of liquid feedstocks such as naphtha as well as LPGs, and from off-gases produced in fluid catalytic cracking (FCC) units in refineries. The primary source of propylene is from cracking naphtha and other liquids such as gas oil and condensates to produce ethylene. By altering the cracking severity and the feedstock slate, the propylene: ethylene ratio can vary from 0.4:1 to 0.75:1. A growing source of
propylene, particularly in the US, is from refineries where splitters recover the propylene from the off-gases produced
With propylene demand growing faster than ethylene, combined with the building of more ethane crackers (which produce no propylene) rather than naphtha crackers, on-purpose technologies are being employed increasingly to make propylene. Propylene production thus depends heavily on ethylene production. In their quest for more independent energy supply the use of shale gas has completely changed the American market. US crackers – who are more flexible than the European one’s – jumped on the opportunity to run on this cheap energy supply. But shale gas does not contain C3 which is needed for propylene production and the crackers’ output has shifted towards ethylene. Because of this, the American market is struggling for propylene and prices in the US are 20% higher than in the rest of the world. This is probably a structural and lasting change.
In Europe, production will remain constrained, whereby cracker operation will continue to be driven by ethylene demand. Imports of polyethylene (PE) and glycol (MEG) from Middle East will affect local production. Refinery operations will be affected by restricted gasoline demand and low profitability. Western Europe currently has no plans to further increase on-purpose propylene production. Import volumes will remain difficult to source and logistics will be the key.
Bacterial Ingenious The production process of methionine requires six main raw materials: Sulphur, methanol, ammonia, propylene, sulphuric acid and energy (gas – CH4) in the enormous factory with a modern equipment, But can you believe that Escherichia coli and Corynebacterium glutamicum can produce L-methionine by pentose phosphate pathway
The enormous capability of both organisms encourages the development of biotechnological methionine production, whereby the use of metabolic pathway
analysis, as shown, provides valuable advice for future strategies in strain and process improvement.