Carbon　sources　are　critical　factors　influencing　bacterial　bioaugmentation,　however,　the　underlying　mechanisms,　particularly　the　metabolic　characteristics　of　bioaugmented　bacteria　remain　poorly　understood.　The　bioaugmented　bacterium　Rhodococcus　sp.　BH4　secretes　the　quorum　quenching　(QQ)　enzyme　QsdA　to　disrupt　the　quorum　sensing　(QS)　in　the　activated　sludge　(AS)　process,　reducing　AS　yield　in-situ.　This　study　investigated　the　carbon　metabolic　characteristics　of　BH4　and　explored　the　effects　on　bioaugmentation　with　different　influent　carbon　sources.　Because　of　the　absence　of　glucose-specific　phosphoenol　phosphotransferase　system　(PTS),　BH4　prefers　sodium　acetate　to　glucose.　However,　the　lactones　produced　during　extracellular　glucose　metabolism　enhance　BH4　qsdA　expression.　Moreover,　BH4　possess　carbon　catabolite　repression　(CCR),　acetate　inhibits　glucose　utilization.　BH4　microbeads　were　added　to　reactors　with　different　carbon　sources　(R1:　sodium　acetate;　R2:　glucose;　R3:　a　mixture　of　sodium　acetate　and　glucose)　for　in-situ　AS　yield　reduction.　During　operation,　AS　reduction　efficiency　decreased　in　the　following　order:　R1　＞　R3　＞　R2.　R2　and　R3　microbeads　exhibited　similar　QQ　activity　to　R1,　with　less　BH4　biomass　at　5　d.　C-13　labeling　and　Michaelis-Menten　equation　showed　that,　due　to　differences　in　the　competitiveness　of　carbon　sources,　R1　BH4　obtained　the　most　carbon,　whereas　R2　BH4　obtained　the　least　carbon.　Moreover,　acetate　inhibited　glucose　utilization　of　R3　BH4.　Transcriptome　analysis　showed　that　R1　BH4　qsdA　expression　was　the　lowest,　R2　BH4　was　the　most　serious　form　of　programmed　cell　death,　and　the　R3　BH4　PTS　pathway　was　inhibited.　At　10　d,　R1　BH4　biomass　and　microbead　QQ　activity　were　higher　than　that　in　R3,　and　the　R2　BH4　lost　viability　and　QQ　activity.　This　study　provides　new　insights　into　bioaugmentation　from　the　perspectives　of　carbon　source　competitiveness,　carbon　metabolism　pathways,　and　CCR.