Print Email Facebook Twitter Looking for lipases and lipolytic organisms in low-temperature anaerobic reactors treating domestic wastewater Title Looking for lipases and lipolytic organisms in low-temperature anaerobic reactors treating domestic wastewater Author Bashiri, Reihaneh (Newcastle University, United Kingdom) Allen, Ben (Newcastle University, United Kingdom) Shamurad, Burhan (Newcastle University, United Kingdom) Pabst, M. (TU Delft BT/Environmental Biotechnology) Curtis, Thomas P. (Newcastle University, United Kingdom) Ofiţeru, Irina D. (Newcastle University, United Kingdom) Date 2022 Abstract Poor lipid degradation limits low-temperature anaerobic treatment of domestic wastewater even when psychrophiles are used. We combined metagenomics and metaproteomics to find lipolytic bacteria and their potential, and actual, cold-adapted extracellular lipases in anaerobic membrane bioreactors treating domestic wastewater at 4 and 15 °C. Of the 40 recovered putative lipolytic metagenome-assembled genomes (MAGs), only three (Chlorobium, Desulfobacter, and Mycolicibacterium) were common and abundant (relative abundance ≥ 1%) in all reactors. Notably, some MAGs that represented aerobic autotrophs contained lipases. Therefore, we hypothesised that the lipases we found are not always associated with exogenous lipid degradation and can have other roles such as polyhydroxyalkanoates (PHA) accumulation/degradation and interference with the outer membranes of other bacteria. Metaproteomics did not provide sufficient proteome coverage for relatively lower abundant proteins such as lipases though the expression of fadL genes, long-chain fatty acid transporters, was confirmed for four genera (Dechloromonas, Azoarcus, Aeromonas and Sulfurimonas), none of which were recovered as putative lipolytic MAGs. Metaproteomics also confirmed the presence of 15 relatively abundant (≥ 1%) genera in all reactors, of which at least 6 can potentially accumulate lipid/polyhydroxyalkanoates. For most putative lipolytic MAGs, there was no statistically significant correlation between the read abundance and reactor conditions such as temperature, phase (biofilm and bulk liquid), and feed type (treated by ultraviolet light or not). Results obtained by metagenomics and metaproteomics did not confirm each other and extracellular lipases and lipolytic bacteria were not easily identifiable in the anaerobic membrane reactors used in this study. Further work is required to identify the true lipid degraders in these systems. Subject Anaerobic treatmentDomestic wastewaterMetagenomicsMetaproteomicsPsychrophilic extracellular lipases To reference this document use: http://resolver.tudelft.nl/uuid:52fbc30e-78fd-4005-93a1-35143bf5199c DOI https://doi.org/10.1016/j.watres.2022.118115 ISSN 0043-1354 Source Water Research, 212 Part of collection Institutional Repository Document type journal article Rights © 2022 Reihaneh Bashiri, Ben Allen, Burhan Shamurad, M. Pabst, Thomas P. Curtis, Irina D. Ofiţeru Files PDF 1_s2.0_S0043135422000781_main.pdf 2.22 MB Close viewer /islandora/object/uuid:52fbc30e-78fd-4005-93a1-35143bf5199c/datastream/OBJ/view