Succinic Acid Fermentation from Alkaline-Based-Pretreated Hydrolysates of Sugarcane Bagasse Using Actinobacillus succinogenes
摘要
This study focuses on production of succinic acid by fermentation of Actinobacillus succinogenes on sugarcane bagasse hydrolysates which were obtained from a variety of conventional and novel NaOH-based pretreatments in batch fermentation. To illustrate the most compatible pretreatment for succinate production, first sugarcane bagasse was pretreated by 2% and 4% (wt./V) of sodium hydroxide at 90 °C and 140 °C. Then, to obtain the effect of ambient conditions on pretreatment, pretreatment with 4%(wt./V) NaOH at 90 °C was conducted in both open batch and a closed reactor. Additionally, 0 °C pretreatment with 4% (wt./V) sodium hydroxide was applied to indicate the effect of this chemical without heating. The obtained residuals were then hydrolyzed enzymatically and applied as carbon sources for succinic acid fermentation. Presence of air during 4% NaOH pretreatment at 90 °C resulted in one of the highest contents of cellulose which is 67.5%. Followingly, the prementioned pretreatment provided the conditions for highest succinic acid production with yield and productivities of 42% and 0.62 g L− 1 h− 1, respectively. HPLC analysis indicated that use of 4% NaOH at 0 °C produced the least cellulose (25.8%) and the most hemicellulose (47.2%). This caused the bacteria to produce succinate as the second major product after formic acid. In addition, as the hydrolysates encompassed smaller portion of xylose compared to glucose, production of succinic acid increased.