Infra red spectroscopy, flash pyrolysis, thermally assisted hydrolysis and methylation (THM) in the presence of tetramethylammonium hydroxide (TMAH) of cultured and sediment-derived Lingulodinium polyedrum (Dinoflagellata) cyst walls

The macromolecular composition of dinoflagellate cyst walls is poorly understood and is usually referred to as 'sporopollenin-like'. We have carried out micro-Fourier transform infra red (micro-FTIR) analysis of chemically untreated sediment-derived and enzymatically and chemically purified culture-derived Lingulodinium polyedrum cyst walls, which suggests an aliphatic polymer rich in CO bonds and relatively poor in CH ₂ and CH ₃ groups, and which is much closer to cellulose than to sporopollenin or algaenan. This is in agreement with flash pyrolysis-gas chromatography-mass spectrometry (py-GC-MS), with and without tetramethylammonium hydroxide (TMAH) of purified culture derived cyst walls, which indicated an oxygen-rich polymer without normal or isoprenoid carbon chains. The results support a strongly cross-linked carbohydrate-based polymer and as such confirm earlier hypotheses that the cysts were unlike algaenan or sporopollenin, contrasting with the suggestion that the cyst walls were highly aromatic and contained tocopherol as a major monomeric building block.