Acid pretreatment and enzymatic saccharification of brown seaweed for polyhydroxybutyrate (PHB) production using Cupriavidus necator

The brown seaweed Sargassum sp. was used.as a feedstock to produce polyhydroxybutyarte (PHB) using Cupriavidus necator PTCC 1615. In order to release monomeric sugars, dilute acid hydrolysis of Sargassum sp. biomass was followed by enzymatic saccharification. In addition, the effect of different nitrogen sources was evaluated for PHB production. The fermentation of hydrolysate with the ammonium sulfate as selected nitrogen source resulted PHB yield of 0.54 +/- 0.01 g/g reducing sugar. Then, NaCl was used as external stress factor which was added to the media. Addition of 8 g/L NaCl had a positive impact on high PHB yield of 0.74 +/- 0.01 g/g reducing sugar. Increasing trend of NaCl concentration to 16 g/L was found to inhibit the production of PHB. Based on obtained results using 20 g/L of reducing sugar, at desired condition the highest cell dry weight and PHB concentrations were 5.36 +/- 0.22 and 3.93 +/- 0.24 g/L, respectively. The findings of this study reveal that Sargassum sp. is a promising feedstock for biopolymer production. The characteristics of produced PHB were analyzed by FTIR, differential scanning calorimetry and H-1 NMR. (C) 2017 Elsevier B.V. All rights reserved.