Fuente: WIPO "tobacco agriculture" The invention discloses Bacillus altitudinis J45 and an acquisition method and application thereof; the Bacillus altitudinis is Bacillus altitudinis J45 and is already collected in China Center For Type Culture Collection under CCTCC No. M2019666. The acquisition method comprises the steps of separation, screening and purification, to be specific, separating a strain capable of degrading nicotinefrom tobacco plant tissues, screening with a NIM culture medium having nicotine as a sole carbon source, and finally purifying on a culture medium plate. The application of the Bacillus altitudinis J45 includes the steps of fermentation, inoculation and degradation, to be specific, the Bacillus altitudinis J45 is cultured at 30 DEG C for 48-72 hours to obtain a fermentation microbial agent, the fermentation microbial agent is sprayed according to 3-5% of the weight of tobacco in the process of tobacco leaf making or tobacco shredding, and the degradation time is maintained for 4-7 days. The Bacillus altitudinis J45 can provide efficient directional degradation for specific nitrosamines of tobacco, has good stress resistance, is simple, convenient and easy to obtain, is convenient to use, and has high popularization and application values.