The efficient lactic acid production from dried oil palm trunk

This study was to efficiently produce lactic acid, the precursor of poly lactic acid, through simple biochemical conversion process applied to dried oil palm trunk enriched with starch (26.9 g) as well as cellulose (26.6 g) per 100 g dry biomass. The biochemical conversion process consisted simply of hydrothermal treatment, enzymatic hydrolysis and fermentation of pretreated whole slurry. The palm trunk was subjected to hydrothermal treatment of which optimal condition depended on how much hemicelluosic sugar was produced by enzymatic hydrolysis of pretreated whole slurry. At such condition, 43.5 g of glucose per 100 g dry biomass was obtained, but only 23.3 g of that was yielded when pretreated whole slurry was adequately washed with water to remove inhibitors generated during pretreatment. Subsequent lactic acid fermentation of whole pretreated slurry by Lactobacillus paracasei yielded 48 g lactic acid accounting for 89.5 % of theoretical lactic acid yield from the palm trunk, whereas that of washed pretreated biomass showed lower lactic acid yield less than 25 g. This study confirmed that considerable amount of sugars was lost during washing of pretreated slurry due to loss of soluble starch. Moreover, designed simple biochemical conversion process is to be cost-effective viable process suitable for converting the palm trunk to lactic acid without loss of starch. The more detailed results will be presented and discussed.