A marine bacterial isolate, Brevibacterium casei #NIOSBA88 was grown separately in Luria Bertini broth supplemented with 750 mg L-1 Arsenic (III) and 100 mg L-1 Chromium respectively. Similarly, the strain was grown in absence of Arsenic and Chromium, which served as an experimental control. The cells were harvested at different time intervals and proteins were extracted from the cell pellets using in-house protocol (Shah and Damare 2018). The extracted proteins were digested using trypsin following standard protocol. Tryptic digests were injected in LCMS QToF for obtaining spectral library which was used to identify the proteins against a species specific database in NCBI.