Industrial biotechnology goes thermophilic: Thermoanaerobes as promising hosts in the circular carbon economy
Angeliki Sitara, Rémi Hocq, Josef Horvath, Stefan Pflügl
Abstract
• “Second-” and “third-generation” (2G, 3G) feedstocks available today are addressed. • Thermophiles converting renewable feedstocks for circular bioeconomy are reviewed. • Current strategies for metabolic engineering of key thermoanaerobes are discussed. • Bioprocess engineering considerations and fermentation parameters are highlighted. • Several scenarios for C1 or LCB conversion to value-added products are showcased. Transitioning away from fossil feedstocks is imperative to mitigate climate change, and necessitates the utilization of renewable, alternative carbon and energy sources to foster a circular carbon economy. In this context, lignocellulosic biomass and one-carbon compounds emerge as promising feedstocks that could be renewably upgraded by thermophilic anaerobes (thermoanaerobes) via gas fermentation or consolidated bioprocessing to value-added products. In this review, the potential of thermoanaerobes for cost-efficient, effective and sustainable bioproduction is discussed. Metabolic and bioprocess engineering approaches are reviewed to draw a comprehensive picture of current developments and future perspectives for the conversion of renewable feedstocks to chemicals and fuels of interest. Selected bioprocessing scenarios are outlined, offering practical insights into the applicability of thermoanaerobes at a large scale. Collectively, the potential advantages of thermoanaerobes regarding process economics could facilitate an easier transition towards sustainable bioprocesses with renewable feedstocks.