Amino acid purification with activated carbon

There are several ways to produce amino acids. Biotechnological processes, namely fermentation and enzymatic catalysis, are growing in importance, while extraction and chemical synthesis are waning.  

For amino acid production via fermentation, agricultural by-products are generally used as feedstock. Plants such as soybean, wheat, corn, potato, and pea, processed using biotechnology, account for most global revenue. Of the most common amino acids, L-glutamate and L-lysine are generally produced through fermentation of plant-based feedstock.  

For amino acids via extraction, animal sources are most common. Cysteine and tyrosine are produced in this way.  

DL-methionine is still mainly oil-based and usually produced through chemical synthesis.  

Activated carbon can be used to remove unwanted molecules from amino acids, during production and/or as a polishing step. There are two forms: powdered (PAC), and granular (GAC).

PAC is added to batches of amino acid solution to adsorb the contaminants and then filtered out. However, PAC cannot be reactivated and thus creates a waste stream. Furthermore, consumption is usually two-three times higher than for granular activated carbon (GAC).

Therefore, switching to a continuous process using GAC can make sense for clients. GAC is contained in filter units and removes impurities through adsorption onto the filter bed. Once saturated, the carbon can usually be reactivated, improving its cost-effectiveness and sustainability.

However, amino acid manufacturers have high standards in terms of product quality and prefer to reuse their own reactivated carbon instead of partaking in a general pool. For major customers, we can offer dedicated reactivation services, providing sole use and reuse of their own activated carbon.

Activated carbon filtration can also treat vented air emissions and wastewater coming from the amino acid production process.

DESOTEC has extensive experience in designing and implementing solutions based around PAC and GAC for use in amino acid production. We understand that each company within the chemical sector has precise and unique requirements.

Before implementing a full-scale solution, we carry out extensive lab tests and in-situ trials to ascertain the optimal grade of carbon and filter set-up. If, after testing, we do not believe our solution is the optimal one, we will let the client know. We are continually researching and developing ways to improve the products and services we offer clients.

We work closely with clients to maintain very high quality controls. Our expertise enables us to troubleshoot and track down the root cause of any issues that should arise.

Our filters are mobile and supplied on a monthly rental basis, making them a flexible solution for many customers in the chemical sector.

The use of reactivated and renewable based activated carbon in mobile filters is also regarded as sustainable, especially for plant-based amino acid production. The cradle-to-gate CO₂e footprint of plant-based amino acid is reported to be in the order of up to 20 kg CO₂e/kg product. GAC consumption may be around 1kg/100kg product, so would account for less than 0,1% of the total CO₂e.

Once GAC is spent, it is transported away from customers’ sites to DESOTEC facilities in closed filter units. This means that no carbon needs to be handled on site, keeping chemical plants dust and dirt-free. 

In DESOTEC’s furnaces, contaminants are completely destroyed in accordance with European legislation, and the carbon is reactivated. The process is continuously monitored, so only harmless water vapour exits the chimneys.