Heavy metal tolerance of an antarctic bacterial Strain O5 and its antioxidant enzyme activity changes induced by Cu²⁺

Under the heavy metal polluted circumstances, microorganisms certainly have some changes in terms of species, quantity, community structure and diversity to adapt the environments. Now, many heavy metal tolerant microbe groups have been studied. In the study, a heavy metal tolerant and psychrophilic bacterium strain from Antarctica was screened. Based on 16S rDNA sequence analysis, this strain belongs to Planococcus, named as Planococcus sp. O5. The capacity of antimetal of Planococcus sp. O5 is Pb²⁺ > Cu²⁺ > Hg²⁺ > Cd²⁺ > Zn²⁺, and the MICs is 320 mg/L, 130 mg/L, 80 mg/L, 80 mg/L and 40 mg/L, respectively. Lipid peroxidation (indicated by malonydialdehyde content) happened in strain O5 induced with Cu²⁺. At the same time, the antioxidation enzyme activity (such as SOD, POD and CAT) had stimulus-controlled improvement, which is a certain protection against heavy metals. Therefore, as an important feature adapting the stress environments, the activity of antimetal, can reflect the adaptive strategy of microorganism to some extent. This paper studied the activity of antimetal and antioxidation of a bacterial strain, which can help us better understand the bacteria how to adapt the extreme environments.