The engineering toolbox of Parageobacillus thermoglucosidasius

Parageobacillus thermoglucosidasius is a thermophilic Gram-positive bacterium that has been gaining traction as a platform for microbial chemical production (Paredes-Barrada et al. 2024 ). In contrast to the petrochemical-based production strategies currently employed by the chemical industry, biobased production potentially presents a more sustainable approach where chemicals and materials can be synthesised from renewable feedstocks, such as lignocellulosic biomass (Krüger et al. 2018 ; Ewing et al. 2022 ). While industrial research often favours well-characterised mesophilic model organisms like Escherichia coli and Bacillus subtilis , interest in thermophilic host species has grown due to the many advantages associated with high-temperature fermentation, such as a reduced risk of contamination from mesophilic species and reduced cooling costs of large-scale fermentations (Zeldes et al. 2015 ; Calero and Nikel 2019 ; Paredes-Barrada et al. 2024 ). With an optimal growth temperature of around 60 °C, P. thermoglucosidasius has proven itself to be an appealing candidate for the development of moderately thermophilic productions (Paredes-Barrada et al. 2024 ). One key feature that distinguishes P. thermoglucosidasius from many other thermophiles is its receptiveness to genetic engineering approaches. While the engineering toolbox of P. thermoglucosidasius is not as well developed as those of conventional mesophilic model organisms, the tools currently available have allowed for the development of P. thermoglucosidasius strains for the production of both native and non-native compounds including ethanol (Cripps et al. 2009 ; Zhou et al. 2016 ), τ-muurolol (Styles et al. 2021 ), riboflavin (Yang et al. 2020 ), and 2,3-butanediol (Zhou et al. 2020 ; Sheng et al. 2023 ). However, to establish P. thermoglucosidasius as a viable candidate for industrial-scale production, a more robust and comprehensive engineering toolbox is required. To facilitate future developments, the following review provides a summary of engineering tools and methodologies currently available for P. thermoglucosidasius alongside a discussion of desirable advancements.