An ice mantle mixture of carbon monoxide, ammonia (or dinitrogen), and water was irradiated in a highly vacuumed cryostat with ultraviolet light at 10 K. The primary products were identified as amino acid precursors when ammonia was used as a nitrogen source, which strongly suggested abiotic formation of bioorganic compounds in ice mantle of interstellar dusts in molecular clouds. The present results have significant implication for organic formation in interstellar dust ice mantles and the energetics of nitrogen fixation.