Characterization and kinetics of bio-butanol production with Clostridium acetobutylicum ATCC824 using mixed sugar medium simulating microalgae-based carbohydrates

• Simulated microalgae carbohydrate medium was used for biobutanol production.
• Effect of sugar concentration and composition on butanol fermentation was studied.
• Growth and product formation kinetics based on glucose and xylose were determined.
• The potential of using microalgae as feedstock for ABE fermentation is revealed.

Our recent work showed that Chlorella vulgaris JSC-6 can accumulate over 50% carbohydrates per dry weight, which mainly contain glucose and xylose as the monosaccharides. In this study, synthetic mixed sugars simulating the hydrolyzed biomass of C. vulgaris JSC-6 (primarily containing glucose and xylose at a ratio of 5:1–6.5:1) was used as the carbon source for bio-butanol production with Clostridium acetobutylicum ATCC824. The growth and product formation kinetics based on glucose, xylose, and mixtures of the two sugars were determined using Monod-type and Michaelis–Menten models, respectively. C. acetobutylicum ATCC824 can grow faster and produce butanol more efficiently on glucose, while the performance was markedly poorer when using xylose. The butanol production kinetics were quite similar when using glucose alone or using mixed sugars (glucose to xylose ratio = 5:1 or 6.5:1), resulting in a maximum butanol production rate of 0.89–0.93 g/h/L. This work demonstrated the feasibility of using the microalgae-based carbohydrates as the feedstock for biobutanol production with C. acetobutylicum ATCC824.