I have the sequenced data of an organism. but it has three 16srRNA which belong to 3 different organisms. I guess it could be contaminated. How could I extract the contigs belonging to each organism present in the sequence data?
If you truly feel that there are three organisms then you can use
bbsplit.sh (from BBMap suite) to bin your reads into respective organismal pools. This will generally work well as long as the bacterial are distinct enough. You are able to decide what you want to do with reads that multi-map (map to all three reference genomes). e.g. keep in all bins, toss etc.
Use the answer here and ask if you have any questions: A: Tool to separate human and mouse ran seq reads
Since you have bacterial data you could turn off