Evaluation of sugarcane bagasse hemicellulosic hydrolysate for succinic acid production by Actinobacillus succinogenes

Recently, in the chemical production sector, renewable resources have attracted much attention from numerous research groups for the production of value-added chemical. The economic viability of chemical production from biomass is highly dependent on both process efficiency and the price of the feedstock. Hence, utilization of waste and by-product streams from current industrial processes for biochemical production could be the key for the development of cost-competitive integrated biorefinery schemes. Considering the widespread use of succinic acid as a chemical for applications in food and pharmaceutical industries, the main goal of this work was validate xylose consumption by Actinobacillus succinogenes ATCC 55618 for succinic acid production from sugarcane bagasse hemicellulosic hydrolysate. The fermentative process was performed in serum bottles, with 30mL of the medium composed of  detoxified hemicellulosic hydrolysate (DHH) supplemented with nutrients. Serum bottles were incubated at 37 °C and CO₂ sparging was established during fermentation. According to the results, the toxic compounds remaining in the DHH, especially acetic acid and phenols exerted an inhibiting effect in succinic acid production, and the maximum product concentration founded was 3.5g/L. Despite the low concentration of succinic acid, others acids were founded and the presence of them was sufficient to reduce the pH of the medium to values near 5.0. This fact also contributes to affect this bioprocess. On the other hand, xylose assimilation was validate (around 56.3 % of total xylose was consumed), which show the potencial of this hydrolysate as carbon source in bioprocess with yield of 0.13g/g, (11.6 % of theoretical value).