High butanol production from galactose riched red seaweed Gracilaria lemaneiformis by solventogenic Clostridium sp. strain NJ4

Abstract Butanol can be biosynthesized by solventogenic clostridia from starchy based materials; however, the high substrate costs hinder its further commercial production. Red seaweed, an abundant and renewable bioresource has attracted more attention owing to its fast-growth, high carbohydrates and low lignin contents, such as Gracilaria lemaneiformis. The newly isolated Clostridium sp. strain NJ4 possesses relatively high utilization capacities of various mono-sugars including glucose, xylose and galactose. Furthermore, 17.77 g/L of butanol was produced from the mixed sugar of glucose, galactose and xylose fermentation by using strain NJ4, indicating the promising potential for butanol production from red seaweed by using strain NJ4. After concentration and detoxification of G. lemaneiformis hydrolysate, 43.18 g/L and 47.37 g/L of glucose and galactose were achieved. And 12.56 and 19.86 g/L of butanol and acetone-butanol-ethanol were finally produced by using Clostridium sp. strain NJ4, representing the highest butanol production from G. lemaneiformis hydrolysate.