Mining the microbiomes from marine wood-digesting bivalves for novel lignocellulose depolymerizing enzymes

- funded by the BMBF in the framework of the ERA-MBT (Marine Biotechnology) initiative (3rd joint call)

Lignocellulose is a greatly undervalorized biomass and methodologies to convert it to high-value products needs fortification. This plant-derived raw material is the most abundant biomass in Europe and it can be harvested from waste streams found in forest and agricultural industries. A functional bioeconomy depends on the ability to convert lignocellulose to chemicals and fuels, a process called biorefining, which still is in its infancy. A critical step in biorefining is the enzymatic conversion of lignocellulose to soluble sugars and lignin. The cost and the efficiency of enzymes is far from optimal and new enzymes are needed to improve the efficiency and sustainability of lignocellulose depolymerization.

Shipworms are voracious animals with respect to their appetite for wood. These marine bivalves are causing severe damage to all wood found in the sea worldwide. Their digestive system is especially intriguing. Wood engulfed by mechanical rasping is digested by enzymes secreted by a community of symbiotic bacteria located in the gill tissue. The shipworm gill symbionts are specialists in lignocellulose degradation and perform this task by applying a perfected enzyme cocktail in a defined and physiochemically stable environment. Thus, by unravelling the contributions of the individual enzymes in the shipworm cocktail, we have the opportunity to take a leap forward in understanding the fundamental properties of enzymatic lignocellulose degradation.

META-MINE will focus on wood-digesting (xylotrophic) marine bivalves collected from the seas/oceans outside Norway, Germany, The Azores and Romania as a model system for a holistic study of marine lignocellulose degradation. The metagenomes from the bivalves’ gills, caecum and faeces will be studied and novel lignocellulose-degrading enzymes characterized.
The aim is to identify the most important enzymes involved in biomass depolymerization by the shipworm digestive system and additionally aid the selection of genes to be cloned for further characterization. The most abundant enzymes identified will be cloned and characterized for potential in lignocellulose valorization.

For more details on the META-MINE consortium see MetaMine_Homepage and ERA-MarineBiotech -> MetaMine consortium.