Abstract:

Abstract The pineapple industry generates large amounts of unusable waste (peel and core) with adverse environmental impacts. This experimental study aims to systemize the potential of ultrasonic-assisted alkaline pretreatment for xylose production from pineapple peel waste. The best condition for single alkaline pretreatment (1 % NaOH w/v, 100 °C, 60 min) has obtained hemicellulose, cellulose, and lignin composition at 34.80 %, 32.16 %, and 8.66 %, respectively, retained in the biomass. Meanwhile, a combination of alkaline (1 % NaOH, w/v) and ultrasonic (frequency 40 kHz, 45 min) pretreatment has obtained the percentage yield of hemicellulose and lignin at 51.15 % and 7.15 %, respectively. Both single alkaline and ultrasonic-assisted alkaline pretreated samples were subsequently hydrolyzed with 2 % H2SO4 (w/v). After acid hydrolysis for 30 min, the maximum xylose concentration of 48.85 g.L-1 was achieved by using ultrasonic-assisted alkaline pretreatment, while single alkaline pretreatment contributed to the lowest yield of xylose (37.11 g.L-1). It is shown that the ultrasonic-assisted alkaline treatment is more favorable than single alkaline pretreatment as it can produce high xylose concentration after the subsequent hydrolysis. These results indicated that ultrasonic-assisted alkaline pretreatment and its subsequent acid hydrolysis were appropriate for producing xylose from pineapple peel waste.

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