Abstract: Objective: To compare antioxidant enzyme activities in 6 strains of Nostoc commune and screen the strain with higher stress resistance. Methods: Catalase (CAT) and ascorbate peroxidase (APX) were determined by spectrophotometry. Glutathione peroxidase (GSH-PX) was determined by DTNB staining method. Results: the highest activity of CAT was determined in Heyeping strain, which revealed a significant difference from the other five. In addition, Qiuqiangou stain revealed significantly higher activities of GSH-PX and APX than the other strains. Conclusion: Qiuqiangou strain has higher stress resistance than the other strains investigated on the basis of antioxidant analysis.

Key words: Nostoc commune, catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GSH-PX)