Production of poly(3‐hydroxybutyric acid) by fed‐batch culture of <i>Alcaligenes eutrophus</i> with glucose concentration control

TLDR

Alcaligenes eutrophus NCIMB 11599 was cultivated in an automatic fed‑batch system to produce poly(3‑hydroxybutyric acid) from glucose. The study examined how ammonium limitation at different culture phases affects PHB synthesis. Glucose levels were maintained at 10–20 g L⁻¹ using exit‑gas mass‑spectrometer data and an online glucose analyzer. Stopping ammonia feeding at a higher cell density (70 g L⁻¹) raised cell and PHB concentrations, achieving 121 g L⁻¹ PHB, 164 g L⁻¹ cells, a 76 % dry‑cell PHB content, 2.42 g L⁻¹ h⁻¹ productivity, and a 0.3 g PHB g⁻¹ glucose yield within 50 h.

Abstract

Abstract Alcaligenes eutrophus NCIMB 11599 was cultivated to produce poly(3‐hydroxybutyric acid) (PHB) from glucose by the automatic fed‐batch culture technique. The glucose concentration of the culture broth was controlled at 10 to 20 g/L by two methods: using exit gas data obtained from a mass spectrometer and using an on‐line glucose analyzer. The effect of ammonium limitation on PHB synthesis at different culture phases was studied. The final cell concentration, PHB concentration, and PHB productivity increased as ammonia feeding was stopped at a higher cell concentration. High concentrations of PHB (121 g/L) and total cells (164 g/L) were obtained in 50 h when ammonia feeding was stopped at the cell concentration of 70 g/L. The maximum PHB content reached 76% of dry cell weight and the productivity was 2.42 g/L h with the yield of 0.3 g PHB/g glucose.