Protein Extraction – Process Development and Optimization of Yield

Abstract

Straumann® Emdogain® is a protein-based gel used in dentistry for tissue regeneration. Emdogain® contains enamel matrix proteins, which are mainly amelogenin proteins. These are obtained through weakly acidic extraction from porcine tooth buds. Embedded in the enamel matrix is also hydroxyapatite which releases calcium ions. These ions saturate the solution, and the protein extraction halts. An attempt was made to remove calcium from the solution, hopefully postponing the saturation, thus increasing the protein yield. This was done by recirculation of extraction solution through a cation exchange column, with an ultrafilter before to prevent proteins from binding the column. Additionally, the current setup was evaluated using different amounts of raw material, to evaluate protein yield.

The new extraction method was difficult to operate due to filter fouling and low tubing durability. However, the successful trials generated higher protein yields than the current extraction method. The two methods extracted proteins of similar composition, which was concluded using SEC HPLC and SDS-PAGE.

A stronger acid was used to evaluate whether the protein yield could be increased, but this yielded less protein than before. Modifications of the new setup to prevent filter fouling included introduction of a prefilter or doubling the ultrafilter area. These were however unsuccessful, and double filter area only worked if the flow was interrupted overnight.

Simple stability studies were also carried out. These showed that when refrigerated, the extraction samples change in protein composition fast while thermostabilized production samples were stable after years of storage. Studying a frozen sample indicated slower protein degradation in comparison to the refrigerated extraction samples.

Popular Abstract

Removal of calcium for more efficient protein extraction

Emdogain® is a protein-based gel used in dentistry, where a unique set of proteins is extracted from slaughter rest products. These proteins contribute to regeneration of not only lost tooth-supporting tissue but also formation of new bone!

Emdogain® is used by dentists to treat periodontitis, which in severe cases causes tooth loss. If you apply Emdogain® to the damaged area, it has been seen that it can recruit cells that trigger the formation of new tissue around the damaged tooth. Emdogain® is, to say the least, an important and unique product that is produced by Straumann Group Biora Manufacturing in Malmö. The current production of Emdogain® occurs in batches, where about 25 000 syringes can be obtained for each batch. It was investigated whether it is possible to extract more proteins, thus possibly enabling production of more syringes, from the same amount of raw material. This was tried through modifications of the first step in the production where the proteins are extracted in a weak acetic acid solution. The proteins, which to 90% consists of proteins of the so-called amelogenin family, have a high affinity for the calcium-rich mineral hydroxyapatite. Hydroxyapatite is the most abundant mineral in tooth enamel. When extracting the proteins, hydroxyapatite is released as well and is dissolved in the acetic acid solution. The calcium from hydroxyapatite saturates the protein solution, limiting how much protein can be extracted. Theoretically, if calcium could be removed from the solution, you should be able to extract more protein. This was tested by recirculating the extraction solution through a column that binds the calcium. The results showed that the hypothesis seemed to be correct – more protein was obtained from the same amount of raw material. When analyzing the protein content more in detail, it appeared as if the protein composition was the same as well. Thus, it was concluded that it seemed possible to extract more of the same proteins, just by removing calcium from the solution. A curious detail was that when trying to extract in a stronger acid, almost no protein was extracted at all. This was quite unexpected, as the proteins were thought to be soluble in low pH values. This finding further showed that the protein extraction is a very complex process, which depends on many different factors. Focusing on the role of calcium, the results indicate that removal of calcium could increase the protein yield by up to 35%. This means that an additional 8750 syringes could be produced per batch of Emdogain®.

• author: Jutebrant, Ellen
• supervisor: Johan Svensson Bonde
• organization: Pure and Applied Biochemistry; Computational Chemistry
• course: KBKM05 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: process development, protein extraction, protein characterization, applied biochemistry
• language: English
• id: 9202034
• date added to LUP: 2025-09-19 12:52:49
• date last changed: 2025-09-19 12:52:49