Feeding strategies for tuning poly (3-hydroxybutyrate-co-4-hydroxybutyrate) monomeric composition and productivity using Burkholderia sacchari

•Tailoring P(3HB-co-4HB) copolymers by fine-tuning GBL addition in fed-batch culture.•Early addition of precursor in the accumulation phase leads to higher 4HB molar%.•Increase of GBL pulse induces a higher 4HB molar% but decreases the productivity.•The presence of glucose enhances the yield of 4HB on the precursor.