Differential catalase activity and tolerance to hydrogen peroxide in the filamentous cyanobacteria Nostoc punctiforme ATCC 29113 and Anabaena sp. PCC 7120

Abstract Photoautotrophic cyanobacteria often confront hydrogen peroxide (H2O2), a reactive oxygen species potentially toxic to cells when present in sufficiently high concentrations. In this study, H2O2 tolerance ability of filamentous cyanobacteria Nostoc punctiforme ATCC 29133 (Nostoc 29133) and Anabaena sp. PCC 7120 (Anabaena 7120) was investigated. Nostoc 29133 was better able to tolerate H2O2-induced inhibition of chlorophyll a and photosystem II performance, as compared to Anabaena 7120. The intracellular hydroperoxide level (indicator of oxidative status) also did not exhibit as much a rise in Nostoc 29133, as it did in Anabaena 7120 after H2O2 treatment. Accordingly, Nostoc 29133 showed higher intrinsic constitutive catalase activity than Anabaena 7120 indicating that the superior tolerance of Nostoc 29133 stems from its higher ability to decompose H2O2. It is suggested that difference in H2O2 tolerance between closely related filamentous cyanobacteria, as is borne out by this study, may be taken into account for judicious selection and effective use of strains in biotechnology.