Gut　dysbiosis　is　a　characteristic　feature　of　obesity　and　targeting　gut　microbiota　presents　a　promising　approach　to　attenuate　obesity.　Euglena　gracilis　polysaccharide　(EGP)　has　emerged　as　a　potential　prebiotic　capable　of　promoting　health-beneficial　bacteria.　However,　its　effects　on　the　gut　dysbiosis　of　obese　individuals　remain　unclear.　This　study　investigated　the　impacts　of　EGP　on　gut　microbiota　from　both　non-obese　and　obese　individuals　using　an　in　vitro　fermentation　model.　Results　showed　that　EGP　significantly　altered　the　gut　microbiota　composition　and　metabolism.　Specifically,　EGP　improved　the　relative　abundance　of　Paeniclostridium,　Clostridium_sensu_stricto_1　and　Paraclostridium　of　the　non-obese　individuals　and　Providencia,　Enterococcus　and　Bacteroides　of　the　obese　individuals.　Metabolomics　results　showed　EGP　significantly　altered　the　lipid　metabolism　especially　in　the　obese　group　with　enriched　bile　secretion　and　cholesterol　metabolism　pathways.　Noting　that　acetic　acid　was　significantly　increased　in　both　groups,　these　acetic　acid　favorable　microbiota　from　non-obese　individuals　was　collected　with　acetic　acid　supplementation.　Transplantation　of　these　acetic　acid-induced　microbiota　(AAiM)　notably　improved　the　richness　and　diversity　of　fecal　microbiota　of　the　obese　individuals,　enhancing　the　growth　of　probiotics　like　Bacteroides　and　Bifidobacterium.　Consequently,　AAiM　significantly　restructured　macronutrients　(including　amino　acids,　carbohydrates　and　lipids)　metabolism　of　the　gut　microbiota　from　obese　individuals.　Altogether,　this　study　underscores　the　potential　of　EGP　and　acetic　acid　favorable　microbiota　in　manipulating　obesity-associated　gut　dysbiosis　via　acetic　acid　production.