Isolation and production of polyhydroxybutyrate (PHB) from Bacillus pumilus NMG5 strain for bioplastic production and treatment of wastewater from paper factories

Polyhydroxybutyrate (PHB) has the potential to replace traditional plastics and limit environmental pollution caused by plastic waste. This study combined wastewater treatment with PHB production to reduce costs. Bacteria capable of synthesizing PHB were isolated from paper mill wastewater and identified using Matrix Assisted Laser Desorption/Ionization–Time of Flight (MALDI-TOF) mass spectrometry and 16S rRNA gene analysis. Bacillus pumilus NMG5 strain was found to have a good yield in modified Nutrient Broth culture, reaching 42.28% of dry biomass. The PHB product was analyzed using FTIR spectroscopy and 1H NMR spectroscopy. The bacterial strain was also tested for its ability to treat paper mill wastewater, and it showed impressive results in terms of biochemical oxygen demand (COD), total nitrogen, and total phosphorus, with efficiencies of 95.93%, 79.36%, and 83.55%, respectively. The study found that wastewater treatment combined with PHB production was a promising solution to reduce costs and limit environmental pollution. The bacterial strain B. pumilus NMG5 had a high yield of PHB, and the PHB product was of high quality, as confirmed by FTIR and 1H NMR spectroscopy. Furthermore, the bacterial strain showed impressive results in treating paper mill wastewater with high COD, total nitrogen, and total phosphorus efficiencies. These results suggest that this harmless bacterium could be used in paper mill wastewater treatment systems to produce PHB, providing a sustainable and environmentally friendly solution.