Abstract Concerns about feasibility, separability, settleability, efficiency once hampered studies on polyhydroxyalkanoates (PHAs) production, which mainly focused on single strain microorganism or activated sludge rather than artificial microbial consortia. Here, a medium chain length PHAs (mcl-PHAs) producing Pseudomonas–Saccharomyces consortium with xylose as the main substrate was studied. Mcl-PHAs accumulation increased from 12.69 mg·L−1 to 152.3 mg·L−1 without any optimization method. The presence of Saccharomyces cerevisiae, though in a relatively low concentration, improved the sedimentation of cell mass of the mixed culture by 60%. Reasons for better sedimentation of the consortium were complex: first, the length of Pseudomonas putida increased two to three times in the consortium; second, the positive surface charge of P. putida was neutralized by S. cerevisiae; third, the adhesion proteins on the surface of S. cerevisiae interacted with the P. putida.
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