Semi-automated monitoring of longitudinal microbial metabolic dynamics: A study case for lignin degradation

This study introduces a low-cost, open-source, semi-automated bioreactor system, developed using Arduino and Raspberry Pi, for longitudinal microbial culture studies. The system protocol includes detailed instructions for custom-designed components, specifications for easily purchasable parts, and open-source code for a web-based control interface. It was validated for sterility and tested in a case study involving the cultivation of Phanerochaete chrysosporium and Trichoderma reesei to assess their metabolic dynamics, both in isolation and co-culture, for lignin degradation. Using mass spectrometry coupled with gas chromatography, several lignin degradation intermediates were annotated, including 4-hydroxybenzoic acid, vanillic acid, and ferulic acid, along with their temporal variation profiles over 25 days. The results highlighted potential synergy between the two fungal species in lignin breakdown, while also demonstrating the bioreactors flexibility and suitability for diverse biotechnological applications, particularly in the field of bio-degradation and waste valorization.