Comparison of Low-Temperature Alkali/Urea Pretreatments for Ethanol Production from Wheat Straw

2021 ◽  
Vol 15 (3) ◽  
pp. 399-407
Author(s):  
Zahoor ◽  
Wen Wang ◽  
Xuesong Tan ◽  
Qiang Yu ◽  
Yongming Sun ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Enzymatic Hydrolysis ◽  
Low Temperature ◽  
Ethanol Production ◽  
Wheat Straw ◽  
Response Surface ◽  
Cellulosic Ethanol ◽  
Enzymatic Saccharification ◽  
Hydrolysis Of ◽  
Bioethanol Yield

NaOH/urea (NU) pretreatment at lower than 0 °C has been frequently applied for improving bio-conversion of lignocellulose, but the wastewater generated from the pretreatment process is hard to dispose. KOH/urea (KU) pretreatment for enhancing bioconversion of lignocellulose has recently attracted researchers’ attention due to the recycling of wastewater for facilitating crops’ growth. This study compared the effects of NU and KU pretreatments at cold conditions on the enzymatic hydrolysis and bioethanol yield from wheat straw (WS). By using response surface methodology an optimal pretreatment with an equal ratio of alkali/urea (4% w/v) at −20 °C for 3 h was established. The enzymatic hydrolysis of KU-treated WS was 81.17%, which was similar to that of NU-treated WS (83.72%) under the same condition. It means that KU pretreatment has equal ability to NU pretreatment to improve enzymatic saccharification of lignocellulose. KU pretreatment has the promising potential to replace NU pretreatment for facilitating bioconversion of lignocellulose in cold conditions due to the clean way to recycle its wastewater as fertilizer for crop growth. Hence, KU pretreatment combined with enzymatic hydrolysis and fermentation could be a promising green way to cellulosic ethanol production with zero waste emission.

scholarly journals Optimization of Sodium Hydroxide Pretreatment and Enzymatic Hydrolysis of Wheat Straw Powder by Cellulases and Xylanases From Aspergillus Niger HQ-1 Using Response Surface Methodology

2021 ◽  
Author(s):  
Hui Zhang ◽  
Junhui Wu
Keyword(s):  
Response Surface Methodology ◽  
Enzymatic Hydrolysis ◽  
Aspergillus Niger ◽  
Sodium Hydroxide ◽  
Wheat Straw ◽  
Response Surface ◽  
Sodium Hydroxide Solution ◽  
Solid Loading ◽  
Enzyme Loading ◽  
Hydrolysis Of

Abstract To maximize fermentable sugars production, response surface methodology (RSM) was adopted to optimize pretreatment and enzymatic hydrolysis of wheat straw powder (WSP) using the crude cellulases preparation containing xylanases from Aspergillus niger HQ-1. Factors of pretreatment including sodium hydroxide concentration, pretreatment time and temperature were found to have significant effects on sugars production. Results indicated that WSP with particle size 0.3 mm should be pretreated using 1.8% (w/v) sodium hydroxide solution with 25.0% (w/v) of solid loading at 94.0°C for 46.0 min and the optimized pretreatment conditions could result in 90.9% of cellulose recovery, 54.6% of hemicellulose recovery and 72.7% of lignin removal, respectively. Furthermore, variables of enzymatic hydrolysis including enzyme loading, biomass loading and reaction time were proved to have significant effects on sugars yields. After hydrolysis at 50°C for 44.8 h with 7.1% (w/v) of biomass loading, 8.1 FPU/g of enzyme loading and 0.2% (w/v) of Tween-80, maximum yields of reducing sugar (632.92 mg/g) and xylose (149.83 mg/g) could be obtained, respectively. In addition, holocellulose and hemicellulose conversion were 81.6% and 80.0%, respectively. To the best of our knowledge, this is the first report about systematic optimization of sodium hydroxide pretreatment and enzymatic hydrolysis of WSP using RSM.

scholarly journals Optimization of alkali pretreatment of wheat straw to be used as substrate for biofuels production  

2013 ◽  
Vol 59 (No. 12) ◽  
pp. 537-542 ◽  
Author(s):  
K. Jaisamut ◽  
L. Paulová ◽  
P. Patáková ◽  
M. Rychtera ◽  
K. Melzoch
Keyword(s):  
Response Surface Methodology ◽  
Enzymatic Hydrolysis ◽  
Sodium Hydroxide ◽  
Wheat Straw ◽  
Response Surface ◽  
Fermentable Sugars ◽  
Alkali Pretreatment ◽  
The Media ◽  
Pretreatment Conditions ◽  
Expert Designer

Alkali pretreatment of wheat straw was optimized by response surface methodology to maximize yields of fermentable sugars in subsequent enzymatic hydrolysis and to remove maximum lignin in order to improve rheological attributes of the media. The effects of pretreatment conditions on biomass properties were studied using the Expert Designer software. Concentration of sodium hydroxide and temperature were the factors most affecting pretreatment efficiency. At the optimum (80°C, 39 min, 0.18 g NaOH and 0.06 g lime per g of raw biomass), 93.1 ± 1.0% conversion of cellulose to glucose after enzymatic hydrolysis and 80.3 ± 1.2% yield of monosaccharides (glucose plus xylose and arabinose) from cellulose and hemicellulose of wheat straw were achieved.

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