Large scale production of succinic acid by fermentation of sequential inorganic salt pretreated oil palm empty fruit bunch

Abstract

The abundance of accumulated oil palm wastes has led to their usage as substrate in the production of organic acid such as succinic acid (SA). For the first time, oil palm empty fruit bunch (OPEFB) which was pretreated using inorganic salts was utilized for SA production in a large-scale fermenter. OPEFB was pretreated sequentially using 15% (w/v) Na3PO4.12H2O and 5% (w/v) ZnCl2 solution before undergoing fermentation process in a 16 L bioreactor in the presence of Actinobacillus succinogenes ATCC 55618. The optimum fermentation conditions were adopted from small-scale setting and implemented in the large-scale setting. Two different fermentation approaches were studied; simultaneous saccharification and fermentation (SSF) and modified simultaneous saccharification and fermentation (mSSF). This research revealed that mSSF produced higher concentration of total reducing sugars (TRS) yield and SA compared to the SSF method. SSF of inorganic salts pretreated OPEFB produced maximum SA concentration (38.85 gL-1) and yield (0.39 gg-1). Meanwhile highest TRS yield obtained from pre-hydrolysis was 0.79 gg-1 at 72 h and SA (50.5 gL-1) was acquired under the mSSF at 132 h. Therefore, mSSF is a novel process that has propitious potential for SA production in a large-scale setting which can be further executed in the industrial scale.