Depositional settings as an influencing factor on lipid biomarker distribution in pre-peloids from Serbia and Slovenia: initial step in determining the biotechnological potential

Abstract

Assessing the biotechnological potential of pre-peloids begins with identifying beneficial metabolites derived from microorganisms or higher plant precursors, whose presence depends on environmental conditions during peloid formation. Therefore, this study examines the impact of distinct depositional settings on lipid biomarker distribution in the organic matter (OM) of pre-peloids from freshwater continental (Vrujci, VRU), saline continental (Rusanda, RUS; Ovča, OVC), and marine (Sečovlje, SEC) environments using gas chromatography-mass spectrometry (GC–MS). The OM of the VRU sample is rich in higher-plant-derived odd long-chain n-alkane members, esters of tetracosanoic and octacosanoic acids, C₂₉ regular sterane, retene, and aromatic triterpenoids with ursane or oleanane carbon skeleton. Mixed microalgae/bacteria and higher plant biomass comprise the OM of pre-peloids deposited under saline continental environment settings. A greater participation of microalgae/bacteria in the OM of OVC sample is inferred from the prevalence of short-chain n-C₁₇ alkane and the highest content of fatty acid esters, while bimodal distribution of n-alkanes, with prevalence of long-chain homologs n-C₂₇–n-C₃₃, short-chain C₂₁ and C₂₂ steranes, and C₂₇ regular sterane in the OM of RUS sample, are pointing to mixed microbial/higher plant biomass. The accumulation of short-chain even n-alkane homologs, C₂₈ ster-2-ene and C₂₉ ster-2-ene sterenes, along with C₂₇ hopene and diploptene, possessing (cyano)bacterial origin, dominate the OM of the SEC sample. All the above-mentioned compounds, recognized for possessing a broad spectrum of biological activities, may contribute to the final peloid product quality and applicability.