Isolation of Polyhydroxyalkanoate (PHA)-Producing Azotobacter spp. from Crop Rhizospheres Located in Lima, Peru

Tupa-Andrade L.; Caro-Castro J.; León-Quispe J. · Revista de la Facultad de Ciencias Agrarias (2025) · DOI: 10.48162/rev.39.170

Resumen

PHAs are polyesters found as internal granules in several microorganisms. Azotobacter is known for its ability to produce PHA. This study aimed to isolate Azotobacter from the rhizosphere of selected crops located in Lima and evaluate their PHA-producing potential. Nile Red medium was used for PHA detection, and Sudan Black B staining allowed microscopic observation. Biopolymer production and quantification were carried out in Burk’s medium, PHA minimal medium (PHAMM), and modified PHAMM. In Nile Red medium, 68.2% of strains produced PHA, with Azotobacter AzoLur20 exhibiting the highest production, 2.1 g/L of PHA at 96 hours in PHAMM. However, strain AzoLur19 showed higher productivity and stability, achieving 0.06 g/L*h of PHA. Additionally, Sudan Black B staining in Burk’s medium revealed larger Azotobacter cells with more defined granules. AzoLur19 was classified as Azotobacter chroococcum. In conclusion, Azotobacter species isolated from crops located in Lima can produce PHA with high yields, with A. chroococcum as the predominant species.

Instituciones: Universidad Nacional Mayor de San Marcos