Sustainable bioconversion of agricultural waste substrates into poly (3-hydroxyhexanoate) (mcl-PHA) by Cupriavidus necator DSM 428

Polyhydroxyalkanoate (PHA) synthesised by microbial strains has properties (biocompatible, non-toxic, and biodegradable) that make it appropriate as an environment-friendly plastic component. This research evaluated the cheap carbon substrates (molasses, olive oil, and their mixture) of industrial waste as an alternative to costly ones for the manufacturing enhancement of mcl-PHA by C. necator. The strain was cultured in both nutrient and mineral media with and without nitrogen. mcl-PHA content was found to be 24.33%, 18.66%, and 40% with molasses, olive oil, and a mixture of both substrates, respectively. The chromatographic technique, GCMS, was utilized to confirm the types of PHA monomers (3HB and HHx). The maximum PHA content produced was 2.03 g/L using a combination of substrates compared to molasses (1.41 g/L) and olive oil (1.12 g/L). Morphology exhibits pseudo-spherical granules with comparatively consistent distribution by SEM. FTIR spectroscopy was used to detect PHA presence rapidly. In conclusion, C. necator DSM 428 cultivated on a mixture of substrates is proficient in manufacturing mcl-PHA along with scl-PHA; the type of PHA monomer depends upon the selection of substrate.