Fermentative conversion of unpretreated plant biomass: A thermophilic threshold for indigenous microbial growth. (January 2023)

• Record Type: Journal Article
• Authors: Bing, Ryan G.; Carey, Morgan J.; Laemthong, Tunyaboon; Willard, Daniel J.; Crosby, James R.; Sulis, Daniel B.; Wang, Jack P.; Adams, Michael W.W.; Kelly, Robert M.
• Is Part Of: Bioresource technology. Volume 367(2023)
• Publication Date: 2023-01
• Subjects: Thermophiles -- Lignocellulose -- Consolidated bioprocessing -- Caldicellulosiruptor bescii -- Acetivibrio thermocellus; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.128275
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Abstract: Naturally occurring, microbial contaminants were found in plant biomasses from common bioenergy crops and agricultural wastes. Unexpectedly, indigenous thermophilic microbes were abundant, raising the question of whether they impact thermophilic consolidated bioprocessing fermentations that convert biomass directly into useful bioproducts. Candidate microbial platforms for biomass conversion, Acetivibrio thermocellus (basionym Clostridium thermocellum ; Topt 60 °C) and Caldicellulosiruptor bescii (Topt 78 °C), each degraded a wide variety of plant biomasses, but only A. thermocellus was significantly affected by the presence of indigenous microbial populations harbored by the biomass. Indigenous microbial growth was eliminated at ≥75 °C, conditions where C. bescii thrives, but where A. thermocellus cannot survive. Therefore, 75 °C is the thermophilic threshold to avoid sterilizing pre-treatments on the biomass that prevents native microbes from competing with engineered microbes and forming undesirable by-products. Thermophiles that naturally grow at and above 75 °C offer specific advantages as platform microorganisms for biomass conversion into fuels and chemicals.