In the past three to four months Flemming Borup from Novozymes, together with Kim Simonsen, a lecturer at the School of Conservation in Copenhagen, has been running a project aimed at removing flesh and fat from animal skeletons, also known as 'maceration'.

“We had only done experiments on mice and rats, and we wanted to experiment on some slightly larger animals, an otter or something like that, but then this opportunity came along,” says Flemming Borup.

How to wash a whale skeleton

Obviously, it is not every day you are asked to clean a whale skeleton, but here is how to do it:

  1. Remove the skin and most of the flesh from the whale
  2. Cut the whale into 75-100 cm long pieces and place in a very large vessel
  3. Add hot water (approx. 55°C) until it covers the skeleton completely (approx. 1,000-1,500 l)
  4. Add approx. 5 l of lipase to the vessel and allow to stand for a few hours so that the lipase can break down the fat
  5. Add approx. 5 l of Alcalase®
  6. After two days, change the water and repeat steps 3, 4 and 5 above
  7. Repeat the process until all the flesh and fat have been removed from the skeleton
  8. When all the flesh and fat has been broken down, allow the whale skeleton to stand in the lipase solution for approx. 1 week to remove the oil that the skeleton contains
  9. Hang out the skeleton to dry for 1 week

When all this has been done, you will have a lovely skeleton to hang on the wall.

Skeleton hung up to dry

“The enzymes give the whale a good going-over; the lipase removes the fat and Alcalase removes the flesh,” explains Flemming Borup. “Afterwards we subject the skeleton to controlled drying in a drying cabinet, a bit like with Parma ham.”

The enzymatic method of removing flesh and fat from a whale skeleton is new. With the classic method, scientists have had to wait up to four weeks for the flesh to fall off the bones, but thanks to these enzymes the waiting time has now decreased to around one week. However, this is not the only bonus of using enzymes. Novozymes and the Zoological Museum are hoping and expecting that the subsequent lipase treatment (step H) will help to keep the skeleton nice for longer.

In the past scientists have tried cleaning a whale in Canada using microorganisms and in England using enzymes. Both experiments went splendidly, but this is the first time that such a systematic and scientific approach has been taken. One part of the whale was thus cleaned using a traditional method, and one part was cleaned using enzymes.