Exploring co-fermentation of glucose and galactose using Clostridium acetobutylicum and Clostridium beijerinckii for Biofuels

Abstract

There is growing interest to produce fuels from algae, namely the third generation biofuel. Galactose and glucose are basic chemicals for many red macroalgae, but fermentation of the mixed sugars may suffer significant glucose repression using yeast. Therefore, another fermentation, acetone-butanol-ethanol (ABE) fermentation of the mixed sugars was studied using Clostridium acetobutylicum and Clostridium beijerinckii. Both strains can use either galactose or glucose, and showed an optimal pH at ~ 5.0. Co-fermentation of the mixed sugar showed simultaneous consumption of glucose and galactose, and exhibited solvent production of 4.19 and 4.57 g/L using Clostridium acetobutylicum and Clostridium beijerinckii, respectively. The fermentation can become more industrially practical if improvement in galactose consumption can be further improved in the future.