Surfactants　are　often　used　to　enhance　the　efficacy　of　bioreactors　in　treating　waste　air　streams　containing　hydrophobic　volatile　organic　compounds　(VOCs).　In　this　study,　biosurfactant　-　saponins　was　innovatively　applied　in　a　self-designed　reflux　foam　bioscrubber　(RFB)　to　remove　benzene　vapor　from　waste　gas　stream.　The　optimal　operating　parameters　and　long-term　performance　of　this　saponins　enhanced　RFB　were　investigated.　The　important　optimal　operational　conditions　are　as　follows:　saponins　concentrations　of　40-50　mg/L,　defoam　liquid　reflux　rate　of　60%　and　pH　range　of　6.5-7.　A　90-day　experiment　was　conducted　to　evaluate　the　stability　of　this　system,　and　benzene　removal　rates　stabilized　at　around　99.52　+/-　0.03%　after　day　7.　Microbial　characteristics　in　this　bioreactor　were　also　investigated　using　16　S　rRNA　gene　sequencing　technologies.　The　relative　abundance　of　benzene-degrading　microbial　species,　such　as　Actinobacteria　and　Saccharibacteria,　increased　significantly　after　90　days　of　the　experiment.　Furthermore,　the　analysis　of　metabolic　pathways　revealed　the　presence　of　abundant　degradation　enzymes　and　diverse　degradation　pathways　in　the　RFB　system.　This　study　is　believed　to　be　the　first　to　investigate　such　metabolic　pathways　in　the　context　of　biotechnological　treatment　of　VOCs.　Together,　the　lessons　learned　from　this　study　suggest　that　the　application　of　saponin　is　a　viable　enhancement　for　the　reflux　foam　bioscrubber　system　in　removing　hydrophobic　VOCs　gases.