The limitations of the current protein classification tools in identifying lipolytic features in putative bacterial lipase sequences.

Metagenomics sequencing has generated millions of new protein sequences, most of them with unknown functions. A relatively quick first step for function assignment is to use the existing public protein databases and their scanning tools. However, to date these tools are not able to identify all sequence features like conserved motifs or patterns.

Looking for lipases and lipolytic organisms in low-temperature anaerobic reactors treating domestic wastewater.

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.

Low-Temperature Pretreatment of Organic Feedstocks with Selected Mineral Wastes Sustains Anaerobic Digestion Stability through Trace Metal Release.

A low-cost approach for enhancing mesophilic (37 °C) anaerobic digestion (AD) of organic waste using a low-temperature (37 °C) pretreatment with different mineral wastes (MW) was investigated. A higher and stable methane production rate, in comparison to MW-free controls, was achieved for 80 days at organic loading rates of 1-2 g VS/L·d, using a feed substrate pretreated with incinerator bottom ash (IBA). The boiler ash and cement-based waste pretreatments also produced high methane production rates but with some process instability.