Comparative Study of Usage of Microbial Strains for Monitoring Waste Water Treatment Plants

Domestic sewage treated in municipal sewage treatment plants is only analyzed for its physicochemical properties correction prior to its discharge but as domestic sewage is proved to contain genotoxicity also, it is suggested that the discharge should also be checked for genotoxicity. Many microbial genotoxicity tests are employed for genotoxicity testing. These tests are simple, quick and employ a variety of auxotrophic bacterial strain battery detecting frame shift, point mutation, base pair substitution causing mutagens presence in the sample. Among them various Salmonella typhimurium strains TA98, TA100, TA97a, TA97b, Ta102 , E.Coli. WP2 etc. are very commonly used which requires repetition of experimentation and makes it tedious. Actual speed of experimentation in detection of mutagens is also lost. In the present study four most commonly used strains of auxotrophic bacterium viz. Salmonella typhimurium TA98, TA100, Ta102 and E.Coli. WP2 strain was taken into consideration and were analyzed that in domestic sewage which types of mutagens are present and which strain among these four most commonly used strains is most sensitive and quick in detection of these mutagens. The results of the study showed that domestic sewage and municipal waste water consists of mutagens causing frame shift mutations and base pair substitutions and the auxotrophic bacterial strain which is most effective among the four strain is Salmonella typhimurium strain TA 102 which along with the frame shift mutation detecting strain TA98 can be used for quick assessment of genotoxicity of domestic waste prior to its discharge.