Lactic acid production from oil palm empty fruit bunch using Lactobacillus delbrueckii

Abstract

Indonesia as the global largest oil palm producer generates tremendous solid wastes such as oil palm trunks, fronds, and empty fruit bunch (EFB). Lignocellulose could be a good feedstock candidate for biorefinery application. Lactic acid is one of the major biorefinery products applied in chemical industries, food, cosmetics, pharmaceutical, and others. One of the most rising applications of lactic acid is its usage in poly-lactic acid (PLA) production by lactic acid polymerization. Therefore, this research aims to explore lactic acid production from EFB with cellulolytic enzymes and Lactobacillus delbrueckii as lactic acid bacteria thru separate hydrolysis and fermentation (SHF) methods. EFB treated with alkali explosion was used for this study. The hydrolysis process was conducted at pH 4.8, 50°C, and 150 rpm of agitation for 72 h with 30 FPU/g substrates of cellulolytic enzymes. Subsequently, hydrolyzate was fermented by Lactobacillus delbrueckii to produce lactic acid. Variation of pH (5.5, 6.0, 6.5, and 7.0) and temperatures (55 and 60°C) during fermentation were carried out in this study in order to optimize lactic acid production. The highest lactic acid concentration was produced at pH 5.5. The lactic acid production by Lactobacillus delbrueckii at 55 and 60°C reached 2.3 g/l and 0.9 g/l, respectively. This result indicated that lignocellulosic biomass could be used as non-food feedstock in lactic acid production.