dc.contributor.author	Wan Azelee, Nur Izyan
dc.date.accessioned	2024-06-19T02:36:01Z
dc.date.available	2024-06-19T02:36:01Z
dc.date.issued	2015
dc.description	Thesis (PhD. (Bioprocess Engineering))
dc.description.abstract	Kenaf (Hibiscus cannabinus) is classified as a lignocellulosic biomass that can produce high value for xylooligosaccharides (XOS) production from its hemicellulose composition. The concept for lignocellulose conversion into simple sugars involves a pretreatment process followed by enzymatic hydrolysis. In this study, a two-stage pretreatment step that involved calcium hydroxide and peracetic acid (Ca(OH)2-PPA) was successfully applied on kenaf to remove high percentage of lignin while maintaining most of the hemicellulose composition. The addition of PPA in the pretreatment step significantly improved the percentage of lignin removal compared to Ca(OH)2 alone. Surface morphology analysis of the kenaf after the two-stage pretreatment showed the harshest changes in surface morphology while both the Ca(OH)2 pretreatment and PPA pretreatment alone showed minimum changes. The overall optimised pretreatment conditions for kenaf were found to be 1 g Ca(OH)2/L with 8:1(mL:g) ratio of liquid-Ca(OH)2 at 50 °C for 1.5 h followed by 20% PPA pretreatment at 75 °C for another 2 h. This had effectively removed 59.25% of lignin while maintaining 87.72% and 96.17% of hemicellulose and cellulose, respectively. This pretreated kenaf was subsequently hydrolysed with a recombinant xylanase and the reaction conditions were optimised using central composite design (CCD). The optimised reaction conditions obtained for substrate concentration, enzyme loading, pH, temperature and time were identified as 2%, 400 unit of xylanase activity (U), 4.0, 40 °C and 48 h, respectively. Synergistic effect of enzyme mixture hydrolysis (xylanase:arabinofuranosidase) on pretreated kenaf had also been determined and the optimum ratio of enzyme was found to be 400 U:10 U which corresponded to the ratio of xylanase:arabinofuranosidase, respectively. The optimum conditions obtained from xylanase hydrolysis alone exhibited 665.57 mg/g of reducing sugar yield. Xylobiose yield of 99.45 mg/g was the highest XOS product. Further increase in the reducing sugar and xylobiose yield of 950.29 mg/g and 135.42 mg/g, respectively were observed when arabinofuranosidase was added into the hydrolysis mixture. Activation energy of 25.15 kJ/mol was needed for the xylanase hydrolysis of kenaf.
dc.description.sponsorship	Faculty of Chemical Engineering
dc.identifier.uri	http://openscience.utm.my/handle/123456789/1188
dc.language.iso	en
dc.publisher	Universiti Teknologi Malaysia
dc.subject	Oligosaccharides
dc.subject	Kenaf
dc.subject	Plant biomass
dc.title	Optimisation of kenaf pretreatment and enzymatic reaction conditions of kenaf hemicellulose for xylooligosaccharides production
dc.type	Thesis
dc.type	Dataset

Optimisation of kenaf pretreatment and enzymatic reaction conditions of kenaf hemicellulose for xylooligosaccharides production

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