Project: Engineering microbial communities for the conversion of lignocellulose into medium-chain carboxylates

Acronym	Cell4Chem (Reference Number: 8)
Duration	01/01/2021 - 01/12/2023
Project Topic	One of the major challenges of today’s society is the shift of the chemical industry from being based on fossil feedstocks and relying on unsustainable processes towards renewable resources and eco-friendly manufacturing processes. The development of a circular economy can help keep our Earth well within its planetary boundaries and secure a liveable Earth for generations to come. The Cell4Chem project fits into these endeavours by harnessing the power of microbial communities. Microorganisms are poster children of circular processes, having kick-started the first global elemental cycles and having sustained them ever since. Today, microbial communities are routinely used in biotechnological processes such as wastewater treatment and biogas production, however, the ability to control these systems has been limited. Cell4Chem aims at providing tools and strategies to unlock the full potential of microbial communities and enabling transformation processes that end in high-value products from sustainable feedstocks. Medium-chain carboxylates (MCC) such as caproate and caprylate are speciality chemicals with broad application spectra that can be produced on the carboxylate platform by anaerobic fermentation of complex biomass with bacterial communities. Up to now, the utilisation of sustainable feedstocks such as agro-industrial waste and residues for MCC production is mostly limited to biomass with high ethanol or lactate content, as such electron donors are crucial for reaching efficient MCC production processes. The exploitation of more abundant lignocellulosic biomass has the potential of greatly expanding the application of this new anaerobic fermentation technology, however, it harbours two major bottlenecks, i.e. the poor hydrolysis of cellulose and low internal production of lactate. Cell4Chem tackles these issues on three engineering levels. On the first level, different bacterial strains including lactic acid bacteria will be genetically modified to create metabolic specialists for cellulose hydrolysis and lactate production in a Synthetic Biology approach. On the second level, these specialised bacterial strains will be combined in de novo constructed consortia with various wildtype microorganisms or enriched consortia including chain-elongating bacteria that can convert lactate into MCC. On the third engineering level, anaerobic bioreactors will be operated with microbiota with the aim to develop process strategies for targeted steering of anaerobic fermentation towards MCC formation. Experiences from these reactor experiments will be exploited for tailored upscaling of the most promising designed consortia. The communities will be monitored over time using next-generation amplicon sequencing and metaomics methods such as metagenomics and metaproteomics in order to follow community dynamics and process performance, leading to time series data and the recovery of genomes of not yet described species. This information will be further processed by bioinformatic tools to construct species-specific metabolic models that are combined to quantitative, mechanistic microbial community models, which both are parameterised towards the experimental data in order to elucidate determinants of observed dynamics, and to screen for optimal community compositions (Systems Biology). We will test our hypothesis that microbial communities can serve as novel and flexible catalysts that can be tailored towards using renewable feedstocks and synthesising caproate and caprylate as desired target products in an eco-friendly way. In order to produce MCCs from cellulose-based feedstocks rather than from unsustainable substrates (such as palm oil), the broad method spectrum of Cell4Chem will be applied in a concerted manner to ensure the optimal fit of microbial consortia in these engineered anaerobic fermentation ecosystems.
Network	ERA CoBioTech
Call	3rd Joint Call on Biotechnologies

Project partner

Number	Name	Role	Country
1	Helmholtz Centre for Environmental Research - UFZ	Coordinator	Germany
2	Jožef Stefan Institute (JSI)	Partner	Slovenia
3	CNRS-LCB (Laboratoire de Chimie Bacterienne)	Partner	France
4	NTNU - Norwegian University of Science and Technology	Partner	Norway
5	University of Santiago de Compostela (USC)	Partner	Spain
6	BlueMethano GmbH	Partner	Germany