Abstract: The present invention provides an optical probe apparatus and method for microorganism culture monitoring. The optical probe can be immersed within the microorganisms and include at least one emitter and at least two detectors that excite photosynthetic pigments in the culture medium. The optical probe can measure the culture spectral characteristics, targeting those that are an indication of the healthiness and productivity condition. The optical probe can also include a microcontroller and storage. The microcontroller can compare past measurements of the optical probe with current measurements and determine a health status of the microorganisms. The optical probe is optimized to measure spectral characteristics from the microorganism in real time. The present invention relates to a sensor tune to detect the healthiness condition of photosynthetic microorganisms.