Changes in lipids and sterols during composting

Pyrolysis-gas (Py-GC) chromatography was used to characterize organic [(die thyl ether (DEE) and chloroform (CHCl3)] extracts of raw and composted duck excreta enriched wood shavings from two finishing cycles (C-1 and C-2). Ma terials were collected on days 0, 8 and 23. C1 contained 1.7 % total N whil e C2 contained 0.9 % total N. Py-GC-MS (mass spectrometry) showed that the extracts contained n-alkanes (C-12 to C-32), alkenes (C-12:1 to C-33:1, n-f atty acids (C-12 to C-28), unsaturated fatty acids (C-18:1 and C-18:2), and sterols (cholestene, cholestadiene, stigmastene, stigmastadiene, stigmasta triene, cholesterol, stigmastanol, stigmastanone, stigmastadienone, 17-meth yl dialkylsulfanyl decahydro-1H-cyclopenta [a] phenanthrene, 17-methyl dial kylsulfanyl dodecahydro-1H-cyclopenta [a] phenanthrene, and 17-methyl-17-di alkylsulfanyl decahydro-1H-cyclopenta [a] phenanthrene). Other components i dentified were prystene, squalene (precursor of cholesterol), phthalic acid , diphenyl-propane, diphenylbut-2-ene and 1,3,6 triphenyl hex-4-ene. Our da ta showed significant changes in the lipid composition of duck excreta enri ched wood shavings during composting, which appeared to be related to the t otal N content of the system.