text: Proteins are normally hydrolysed slowly even without enzymes or bacteria, with a half life of 460 years, but can be preserved if they are desiccated, pickled or frozen. Being enclosed in bone also helps preservation. Over time the amino acids tend to racemize, and those with more functional groups are lost earlier. Protein still will degrade on the timescale of a million years. DNA degrades rapidly, lasting only about four years in water. Cellulose and chitin have a half life in water at 25° of about 4.7 million years. Enzymes can accelerate this by a factor of 10. About 10 tons of chiting are produced each year, but it is almost all degraded.
  Lignin is only efficiently degraded by fungi, white rot, or brown rot. These require oxygen.
  Lipids are hydrolysed to fatty acids over long time periods. Plant cuticle waxes are very difficult to degrade, and may survive over geological time periods.