Background: The efficiency of biofuel production depends on the photosynthetic activity of microbes; to maximize their growth it is necessary to continually monitor the environmental conditions. Traditional monitoring methods (such as using electrodes to measure CO2 consumption and/or O2 generation) are typically time- and labor-intensive have low throughput and often require special devices. It would be desirable to simultaneously measure several parameters with a simple robust multiplexed high throughput sensor.