Effect of Dilute Acid and Alkaline Pretreatments on Enzymatic Saccharfication of Palm Tree Trunk Waste for Bioethanol Production

Abstract

The sugar palm tree (Arenga pinnata) was abundant in Indonesia and has high cellulose contents for bioethanol production. However, the lignin content was the major drawback which could inhibit saccharification enzymes and therefore removing the lignin from the biomass is important. This paper evaluated the effects of pretreatments using nitric acid (HNO3) and ammonium hydroxide (NH4OH) at 2 to 10% (v/v) on reducing sugar and ethanol contents and compared with the effects of steam pre-treatment. The pretreated samples were hydrolyzed using cellulase enzymes at pH 5.0 with a substrate concentration of 10% (w/v) for 24 to 72 h at 50 °C. Subsequent assessments of enzymatic saccharification following pre-treatment with 10% (v/v) HNO3 showed maximum reducing and total sugar contents in palm tree trunk waste of 5.320% and 5.834%, respectively, after 72 h of saccharification. Following pretreatment with 10% (v/v) of NH4OH, the maximum reducing and total sugar contents of palm tree trunk waste were 2.892% and 3.556%, respectively, after 72 h of saccharification. In comparison, steam pretreatments gave maximum reducing sugar and total sugar contents of 1.140% and 1.315% under the same conditions. Simultaneous saccharification and fermentation (SSF) was conducted at 37 °C (pH 4.8) and 100 rpm for 120 h using 10% (v/v) Saccharomyces cerevisiae and cellulase enzyme with a substrate concentration of 10% (w/v). The result showed the highest ethanol content of 2.648% was achieved by using 10% (v/v) HNO3. The use of 10% (v/v) NH4OH gained a yield of 0.869% ethanol while the steam pretreatment could obtained 0.102% ethanol. Copyright © 2019 BCREC Group. All rights reserved

Bioethanol Production Optimization from KOH-Pretreated Bombax ceiba Using Saccharomyces cerevisiae through Response Surface Methodology

“…The findings show that SSF is more effective than SHF in terms of energy consumption, time, cost, and greater bioethanol yield. Kusmiyati and coworkers [29] reported 2.648% bioethanol production from pretreated palm tree trunk waste through SSF using S. cerevisiae and cellulase enzymes at 37 • C temperature, 4.8 pH, 10% substrate, and 100 rpm for 120 h. Another study noticed a remarkable ethanol titer from the SHF of an oil palm empty fruit bunch. Hydrolysis at 50 • C, pH 4.8, and 150 rpm of agitation for 96 h yielded 75.48% glucose, which subsequently produced 78.95% ethanol [39].…”

“…Jabasingh and Nachiyar [28] also observed such changes in bagasse. Irfan et al [9] and Kusmiyati et al [29] noticed a rough surface with holes in pretreated wheat straw and palm tree trunk waste, respectively, through SEM.…”

“…Wang et al [45] obtained 5.16 g/L of ethanol using commercial cellulase after 24 h in SSF from biologically delignified poplar chips and the yield was 75%. Kusmiyati and coworkers [29] reported 2.648% bioethanol production from HNO 3 -pretreated palm tree trunk waste through SSF using S. cerevisiae and cellulase enzymes at 37…”

Fermentative Production of Lasiodiplodan by Lasiodiplodia theobromae CCT3966 from Pretreated Sugarcane Straw

“…In this way, 20 g raw sugarcane straw was placed in 500 mL Erlenmeyer flask and 200 mL of dilute HNO 3 was added, followed by vigorous mixing. The flask was then transferred into an autoclave and heated at 121 • C for 60 min [37]. The solid part was then collected, washed with water (pH 7) and dried until the moisture content reached less than 10%.…”