Sourcing soil derived Corynebacterium sp. isolate that outperforms established strains using ROTOR+
Lignocellulosic biomass (LCB) is a catchy name for the ubiquitous plant dry matter waste, rich in biodegradable polymers cellulose, hemi-cellulose and lignin (Figure 2). It’s a byproduct of several industrial processes in agriculture and forestry, such as saw and paper mill waste, sugarcane bagasse, and other plant residue (e.g. straw). Bioprocessing LCB yields various value-added products like biofuels, textile and adhesives, notably contributing to the circular economy (Haq et al., 2020).
LCB must undergo pre-treatments like hydrolysis to release fermentable carbon sources. However, this process also releases known inhibitors to microbial growth.
Researchers from the Technical University of Denmark (Weiẞ et al., 2024) have developed a fast solid-media screening method using Singer Instruments’ ROTOR+ to measure colony fitness as a proxy for liquid-based screens.
The team followed a multi-step screening process:
- They screened and scored 32 strains to find the most suitable ones for LCB bioprocessing. This initial screening took place on agar plates containing various carbon sources.
- Next, they tested the strains’ tolerance to common inhibitors, including acetic acid, formic acid, furfural, 4-HBA, and vanillin.
- Finally, the top-performing strains were chosen for micro-fermentations. Their growth was directly scored in a medium of softwood spent sulfite liquor (SSL), a pulp and paper industry-derived LCB.
The study yielded Corynebacterium sp. ATCC 14747 as the top performer, surpassing Corynebacterium glutamicum, already characterised, engineered and utilised by the industry (Jin et al., 2020).
Rather than relying solely on synthetic biology to improve known strains, this approach leverages innate microbial phenome diversity to provide solutions for environmental sustainability.