The purpose of this paper is to introduce a novel similarity measure, the single-valued pentapartitioned neutrosophic exponential similarity measure (SVPNESM), and the single-valued pentapartitioned neutrosophic weighted exponential similarity measure (SVPNWESM) under the single-valued pentapartitioned neutrosophic set (SVPNS) environment for selecting bacteria on concrete mortar to improve compressive strength and to reduce water absorption, porosity and chloride permeability. In order to improve the properties of concrete, bacteria must fulfill requirements such as increased compressive strength, decreased water absorption capacities, reduced porosity, decreased chloride permeability etc. A novel approach for selecting suitable bacteria in concrete mortar is presented in this study based on such requirements. In this study, suitable bacteria is selected from four bacteria for concrete mortar based on 4 criteria with fixed bacteria concentrations of 105 . Based on this study, Bacillus subtitles is selected among four alternatives as suitable. Furthermore, the proposed MADM method is shown to be well suited to this problem after it has been compared with two existing methods.