An Arduino based automatic pressure evaluation system to quantify growth of non-model anaerobes in culture

Measuring the growth rate of non-model anaerobic microbes typically requires the use of time-consuming and often destructive manual measurements. Here, an Arduino based automatic pressure evaluation system (A-APES) was developed to automatically measure the rate of fermentation gas production as a proxy for microbial growth in anaerobic systems. The A-APES system measures accumulated gas pressure in sealed cultures accurately at high-resolution, while venting the system at programmed intervals to prevent over pressurization. The utility of A-APES is demonstrated in this study by quantifying the growth rate and phases of a biomass-degrading anaerobic gut fungus, which cannot be otherwise measured via conventional techniques due to its association with particulate substrates. Given the utility of the A-APES approach, we provide a complete construction guide to fabricate the device, which is three times less expensive compared to existing commercial alternatives.