Biovalorizing felled oil palm trunk as a sole feedstock for lactic acid production through efficient simultaneous saccharification and fermentation

This study aimed to develop practical biorefinery process for bio-valorizing felled oil palm trunk (OPT) as a sole feedstock for lactic acid (LA) production. OPT was separated into oil palm sap (OPS), vascular bundle (OPT-VB), and parenchyma (OPT-PA) fractions. OPS containing high amounts of sugars (38.69 g/L) and nitrogen (0.63 g/ L), could be used directly for LA production by Lactobacillus acidophilus and also as base medium for simultaneous saccharification and fermentation (SSF) of OTP-VB and OPT-PA. The repeated SSF efficiently utilized cellulosic OPT-VB and produced LA up to 50-71 g/L during five cycles. Due to high water-absorbing and swelling properties of OPT-PA, it could not be initially added at high loadings. It was then intermittently added through fedbatch SSF, which effectively produced LA of 72.85 +/- 1.61 g/L. These strategies have shown the efficient biorefinery process for biovalorization of OPT and may also be applicable to other similar agricultural wastes.