Whole slurry saccharification of mild oxalic acid-pretreated oil palm trunk biomass improves succinic acid production

Abstract

The present work compared two different routes in preparing oil palm trunk biomass (OPTB) hydrolysates for producing industrially-valuable succinic acid (SA). OPTB was initially pretreated with mild oxalic acid (1% w/v) under different reaction time to investigate its effect on the total sugar and inhibitor yields during pretreatment and subsequent enzymatic saccharification. Substantial solubilisation of hemicellulose (56–59 %) was achieved after pretreatment for 3−4 h. After enzymatic saccharification, high cellulose digestibility of 86–87 %, with 22.1–22.2 g sugar per 100 g of raw OPTB from washed pretreated solids (Route 1), and 71–74 %, with 43.2–44.9 g sugar per 100 g of raw OPTB from whole slurry (Route 2) saccharification, respectively was achieved. Fermentation of the hydrolysates derived from Route 2 by Actinobacillus succinogenes 130Z afforded a twofold increase in the SA production compared to that from Route 1. Mass balance calculations showed that 175 g of SA could be produced per kg of OPTB via Route 2 vs. 153 g via Route 1. The proposed approach in this study offers pioneering insights into the greatest improvement in SA yield achievable via efficient biomass utilisation.