Methane emissions and plastic pollution are critical global challenges.The biological conversion of methane to poly-β-hydroxybutyrate (PHB) not only mitigates methane emissions but also provides biodegradable polymer substitutes for petroleum-based materials used in plastics production.This work provides an early overview of the methane-based PHB advances and discusses challenges and related strategies.Recent advances of PHB,including PHB biosynthetic pathways,methanotrophs,bioreactors,and the performances of PHB materials are introduced.Major challenges of methane-based PHB production are discussed in detail;these include low efficiency of methanotrophs,low gas-liquid mass transfer efficiency,and poor material properties.To overcome these limitations,various approaches are also explored,such as feast-famine regimes,engineered microorganisms,gas-permeable membrane bioreactors,two-phase partitioning bioreactors,poly-β-hydroxybutyrate-co-hydroxyvalerate synthesis,and molecular weight manipulation.