Rapid quantification of viable spore by a simple spectrophotometric method

Bacteria used in self-healing of concrete crack need to be embedded into the concrete in the form of dormant spores. However, quantification of viable spores is still a challengeable task due to the lack of rapid, efficient and accurate methods. Considering that viable spores have a higher refractive index than vegetative cells and the refractivity issubject to decrease during the germination process, we attempted to develop a simple spectrophotometric method for the detection of viable spores. By comparison of the results obtained by both spectrophotometric method and colony counting method, a good linear correlation (R=0.99) was achieved between viable spore concentration and OD loss under appropriate conditions. The calibration equation developed could be used to predict the viable spore yield produced in a series of fermentation experiments. Our experiment proved that this novel spectrophotometric method was sensitive, rapid, and easy to perform compared to conventional colony counting method.