[Decomposition of corpses--a microbial degradation process with special reference to mummification, formation of adipocere and incomplete putrified corpes]. / Leichenzersetzung--ein mikrobieller Abbauprozess (unter besonderer Berücksichtigung der Entstehung von Mumien, Fettwachs und Faulleichen).

Decomposition of the human body is a microbial process. It is influenced by the environmental situation and it depends to a high degree on the exchange of substances between the corpse and the environment. Mummification occurs at low humidity or frost. Adipocere arises from lack of oxygen, incomplete putrified corpses develop when there is no exchange of air or water between the corpse and the environment.

Adipocere formation--the result of insufficient microbial degradation.

Decomposition of human tissue is a microbial process. Microorganisms need certain environmental conditions to be able to grow and to degrade organic substances of tissue. Conditions that disturb degradation result in adipocere. Adipocere is a predominantly whitish, crumbly, inodorous, fatty feeling lipid bulk, which is originated mainly from human or animal fat. It may persist for many decades. Three reasons are repeatedly given for adipocere: formation of hydroxy fatty acids, a high amount of water in the environment of the corpse and lack of oxygen. Fatty acids can be exclusively degraded by respiration but not by fermentation. Microorganisms produce polyhydroxy fatty acids as storage substances comparable to human fat, in the presence of a surplus of organic compounds but a lack of other essential substances for the microbial activity like oxygen. In the end, formation of adipocere is the result of oxygen deprivation. In contact with oxygen adipocere can be degraded by microorganisms, but this is a long lasting process as oxygen exchange is very limited in soil and water.

Quantification of adipocere degradation with and without access to oxygen and to the living soil.

Adipocere is formed from body fat in moist and oxygen-deficient decay conditions. The persistence of adipocere may cause problems for the reuse of graves after the expiration of statutory resting times in some countries. Up to now, no quantitative data existed on the persistence of adipocere in either aerated or anoxic conditions. We investigated the rate of degradation (disappearance) of adipocere in five different samples from human corpses. The experimental incubation was (a) in water without air contact, (b) in water with access to air, (c) in physiological saline with access to air, (d) on sterilized quartz sand, (e) in vitro on living soil, and (f) buried 15 cm deep in field soil. The weight loss of the samples was determined after 215 (293) days and half-lives were calculated under the assumption of simple first-order kinetics. Furthermore, the nitrogen content and the fatty acid composition of the adipocere samples were analyzed. The results revealed half-lives that differ between the adipocere samples from 11 to 82 years under anaerobic conditions (mean of all samples, 37 years). In air, the half-life of adipocere was reduced to about one tenth, ranging from 0.7 to 10 years (mean of 2.8 years for all samples incubated in aerated physiological saline, mean of 4.0 years for all samples incubated on living soil in the laboratory). Burying adipocere in a biologically active field soil resulted in half-lives of disappearance from 1.2 years to 2.1 years (mean, 1.5 years). The N content of the adipocere samples ranged between 1.9 and 6.7 mg N g(-1). The sample with the highest N content was also that with the lowest half-life of disappearance in all types of incubation. The fatty acid analysis of the samples revealed a composition typical of adipocere, with a clear dominance of saturated acids (palmitic, myristic and stearic acid) over unsaturated ones. The variation of fatty acid composition between the different adipocere samples could only be attributed partly to their age and the burial conditions. It can be concluded that the aeration of adipocere-laden corpses will lead to a disappearance of adipocere (and hence restitution of the decay process) within a time span of several years.