High-throughput screening of acetogenic strains for growth and metabolite profiles on readily available biomass.

Abundant biomass, including industrial waste streams and second-generation (2G) and third-generation (3G) feedstocks, offers significant potential for sustainable bioconversion, nevertheless challenges such as fermentation inhibitors, CO losses and substrate selectivity of traditional microbial hosts hinder process efficiency. In this study, we address these challenges by exploring acetogenic bacteria as alternative microbial hosts. Using a newly established high-throughput method, acetogens were evaluated for their capacity to hydrolyse and metabolize variety of substrates derived from 2G and 3G feedstocks and industrial waste streams.

Pressure fermentation to boost CO-based poly(3-hydroxybutyrate) production using Cupriavidus necator.

CO-based poly(3-hydroxybutyrate) (PHB) can be produced by the versatile bacterium Cupriavidus necator through chemolithoautotrophic fermentation, using a gas mixture consisting of CO, H, and O. Despite offering a propitious route for carbon-neutral bioplastic manufacturing, its adoption is currently hampered by the wide explosive range of the required gas mixture, as well as the limited gas-to-liquid mass transfer rates. To address these challenges, pressure fermentation was applied as a robust and effective strategy, while ensuring safe operation by adhering to the limiting O concentration, utilizing state-of-the-art bioreactors.

Industrial side streams as sustainable substrates for microbial production of poly(3-hydroxybutyrate) (PHB).

Poly(3-hydroxybutyrate) (PHB) is a microbially produced biopolymer that is emerging as a propitious alternative to petroleum-based plastics owing to its biodegradable and biocompatible properties. However, to date, the relatively high costs related to the PHB production process are hampering its widespread commercialization. Since feedstock costs add up to half of the total production costs, ample research has been focusing on the use of inexpensive industrial side streams as carbon sources.

Advanced PHB fermentation strategies with CO-derived organic acids.

Over the past decade, formic acid and acetic acid have gained increasing attention as alternative feedstocks for poly-3-hydroxybutyrate (PHB) production as these potentially CO-derived molecules are naturally assimilated by Cupriavidus necator. Both organic acids were individually evaluated in fed-batch fermentations at bioreactor scale. Acetic acid was revealed as the most promising carbon source yielding 42.