Production of polyhydroxyalkanoates containing monomers conferring amorphous and elastomeric properties from renewable resources: Current status and future perspectives

[Display omitted] •Polyhydroxyalkanoate (PHA) is a promising alternative to petrochemical-based plastics.•The incorporation of monomers such as 3HP, 3HHx, 4HV, 4HB, 5HV, and 6HHx in P(3HB) shows amorphous and elastomer properties.•Lignocellulosic biomass, Levulinic acid, Glycerol and Waste oil can be utilized as feedstocks for sustainable and inexpensive PHA production.•Metabolic engineering can contribute to the expansion of the PHA portfolio from renewable resources. Petrochemical-based plastics cause environmental pollution and threaten humans and ecosystems. Polyhydroxyalkanoate (PHA) is considered a promising alternative to nondegradable plastics since it is eco-friendly and biodegradable polymer having similar properties to conventional plastics. PHA’s material properties are generally determined by composition and type of monomers in PHA. PHA can be designed in tailor-made manner for their suitable application areas. Among many monomers in PHAs, ω-hydroxalkanoates such as 3-hydroxypropionate (3HP), 4-hydroxybutyrate (4HB), 5-hydroxyvalerate (5HV), and 6-hydroxyhexanoate (6HHx) and medium-chain-length 3-hydroxyalkanoate such as 3-hydroxyhexanoate (3HHx) and 4-hydroxyvalerate (4HV), have been examined as potential monomers able to confer amorphous and elastomer properties when these are incorporated as comonomer in poly(3-hydroxybutyrate) copolymer that has 3HB as main monomer along with comonomers in different monomer fraction. Herein, recent advances in production of PHAs designed to have amorphous and elastomeric properties from renewable sources such as lignocellulose, levulinic acid, crude glycerol, and waste oil are discussed.