Rapid Detection of Microbial Count Using Portable Bioluminescence-based Biosensor

The method of fluorimetric determination of adenosine 5'-triphosphate(ATP),which is approximately in the same level in every living bacterial cells,was used to detect the microbial count.A portable biosensor was developed to detect microbial count,which integrated ATP extracting and detecting together.The ATP can be extracted absolutely under the optimal conditions:CTMAB was chosen as extractant,extraction time was 2 min,and concentrations of the extractant and relevant neutralizing reagent were 5 and 7.5 mmol/L,respectively.Under the optimized experimental conditions,a linear response of luminescence intensity to microbial count was obtained from 58 to 5.89×107 cfu/mL with a correlation coefficient of 0.979.Moreover,the results correlated well with those from the conventional plate count method with a correlation coefficient of 0.873.The results proved that the biosensor can be applied in scene.The whole time from sampling to the ATP extraction to obtain the results was less than 5 min.The proposed biosensor with characters of low cost,easy operation and fast response provided potential application for rapid evaluation of bacterial contamination in food industry,environment monitoring and other fields.