Production and characterization of poly(3-hydroxybutyrate) generated by Alcaligenes latus using lactose and whey after acid protein precipitation process

Whey after acid protein precipitation was used as substrate for PHB production in orbital shaker using Alcaligenes latus. Statistical analysis determined the most appropriate hydroxide for pH neutralization of whey after protein precipitation among NH 4 OH, KOH and NaOH 10% w/v. The results were compared to those of commercial lactose. A scale-up test in a 4 L bioreactor was done at 35 °C, 750 rpm, 7 L/min air flow, and 6.5 pH. The PHB was characterized through Fourier Transform Infrared Spectroscopy, thermogravimetry and differential scanning calorimetry. NH 4 OH provided the best results for productivity ( p ), 0.11 g/L.h, and for polymer yield, (Y P/S ), 1.08 g/g. The bioreactor experiment resulted in lower p and Y P/S. PHB showed maximum degradation temperature (291 °C), melting temperature (169 °C), and chemical properties similar to those of standard PHB. The use of whey as a substrate for PHB production did not affect significantly the final product quality.