Effects Of Pretreatment And Enzymatic Hydrolysis On Oil Palm Frond For Use As Yeast Cultivation Medium
| dc.contributor.author | Eng, Kean Tiek | |
| dc.date.accessioned | 2019-06-18T06:33:18Z | |
| dc.date.available | 2019-06-18T06:33:18Z | |
| dc.date.issued | 2012 | |
| dc.description.abstract | The advantage of acid hydrolysis is time consumed is much lower (10 minutes to 6 hours), as compared to enzymatic hydrolysis time is counted in days (Goldstein, 1983 and Wenzl, 1970). However, acid hydrolysis is hampered by non-selectivity and by-products formation from sugar decomposition (Fan et al., 1982). During acid hydrolysis, hemicelluloses are degraded to xylose, mannose, acetic acid, galactose and glucose; cellulose is hydrolyzed to glucose. At high temperature and pressure xylose is further degraded to furfural (Dunlop, 1948). Similarly, 5-hydroxymethyl furfural (HMF) is formed from hexose degradation, and HMF may be further degraded to form levulinic acid (Ulbricht et al., 1984). During acid hydrolysis, partial of lignin will be degraded to phenolic compounds (Bardet et al., 1985) Those by-products are fermentation inhibitors. When studying ethanol production by yeast Pichia stipitis, Robert et al. (1991) observed that furfural concentration lower than 0.5 g/l had a positive effect on cell growth, whereas concentration above 2.0 g/l inhibited cell growth almost completely. According to Delgenes et al. (1996), P.stipiitis growth was reduced by 43%, 70%and 100% when HMF concentration in the medium was 0.5, 0.75 and 1.5 g/l respectively. In the lignocellulose hydrolysates, the concentration of sugars as well as the concentration of hydrolysis by-product is depended on hydrolysis conditions (Clausen and Gaddy, 1988). The hydrolysis temperature, time, and acid concentration influence the generation of inhibitor. To combine the residence time and temperature during hydrolysis into single reaction ordinate, Overend and Chornet (1987) had defined a severity factor according to following equation: Log Ro = t e (T-100)/ 14.75 Where t is residence time and T is hydrolysis temperature. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/8320 | |
| dc.language.iso | en | en_US |
| dc.publisher | Universiti Sains Malaysia | en_US |
| dc.subject | Enzymatic hydrolysis on oil palm frond | en_US |
| dc.subject | use as yeast cultivation medium | en_US |
| dc.title | Effects Of Pretreatment And Enzymatic Hydrolysis On Oil Palm Frond For Use As Yeast Cultivation Medium | en_US |
| dc.type | Thesis | en_US |
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