Cellulosic ethanol: interactions between cultivar and enzyme loading in wheat straw processing

The aim of this study is to find the optimal pretreatment conditions and hydrolysis in order to obtain a high yield of bioethanol from wheat straw. The pretreatments were performed with different concentrations of sulphuric acid 1, 2 and 3% (v/v), and were followed by an enzymatic hydrolysis that was performed by varying the solid-to-liquid ratio (1/20, 1/25 and 1/30 g/mL) and the enzyme dose (30/30 µL/g, 60/60 µL/g and 90/90 µL/g Viscozyme® L/Celluclast® 1.5 L). This mix of enzymes was used for the first time in the hydrolysis process of wheat straws which was previously pretreated with dilute sulfuric acid. Scanning electron microscopy indicated significant differences in the structural composition of the samples because of the pretreatment with H2SO4 at different concentrations, and ATR-FTIR analysis highlighted the changes in the chemical composition in the pretreated wheat straw as compared to the untreated one. HPLC-RID was used to identify and quantify the carbohydrates content resulted from enzymatic hydrolysis to evaluate the potential of using wheat straws as a raw material for production of cellulosic ethanol in Romania. The highest degradation of lignocellulosic material was obtained in the case of pretreatment with 3% H2SO4 (v/v), a solid-to-liquid ratio of 1/30 and an enzyme dose of 90/90 µL/g. Simultaneous saccharification and fermentation were performed using Saccharomyces cerevisiae yeast, and for monitoring the fermentation process a BlueSens equipment was used provided with ethanol, O2 and CO2 cap sensors mounted on the fermentation flasks. The highest concentration of bioethanol was obtained after 48 h of fermentation and it reached 1.20% (v/v).

Download Full-text

Cultivar variation and selection potential relevant to the production of cellulosic ethanol from wheat straw

Biomass and Bioenergy ◽

10.1016/j.biombioe.2011.12.009 ◽

2012 ◽

Vol 37 ◽

pp. 221-228 ◽

Cited By ~ 44

Author(s):

J. Lindedam ◽

S.B. Andersen ◽

J. DeMartini ◽

S. Bruun ◽

H. Jørgensen ◽

...

Keyword(s):

Wheat Straw ◽

Cellulosic Ethanol ◽

Cultivar Variation ◽

Variation And Selection

Download Full-text

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

10.21203/rs.3.rs-374151/v1 ◽

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.

Download Full-text

Optimisation of enzymatic saccharification of wheat straw pre-treated with sodium hydroxide

Scientific Reports ◽

10.1038/s41598-021-02693-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhiquan Wang ◽

Suqing Wu ◽

Chunzhen Fan ◽

Xiangyong Zheng ◽

Wei Zhang ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Treatment Time ◽

Solid Content ◽

Reducing Sugar ◽

Sugar Yield ◽

Experimental Result ◽

Enzyme Loading ◽

Hydrolysis Time ◽

Pre Treatment

AbstractTo enhance the reducing sugar yield in enzymatic hydrolysis, various factors (NaOH concentration, solid content and pre-treatment time) that affect the pre-treatment process were investigated and evaluated based on the reducing sugar yield of the subsequent enzymatic hydrolysis. The enzymatic hydrolysis was based on the cellulase from Trichoderma reesi ATCC 26921, the optimum NaOH pre-treatment conditions were an NaOH concentration of 1.0% (w/w), a solid content of 5.0% (w/v) and a pre-treatment time of 60 min. Various parameters that affect the enzymatic hydrolysis of wheat straw, including the solid content, enzyme loading, pH and hydrolysis time, were investigated and optimized through a Box–Behnken design and response surface methodology. The predicted optimum conditions for enzymatic hydrolysis were a solid content of 8.0% (w/v), an enzyme loading of 35 FPU/g substrate, a temperature of 50 °C, a pH of 5.3 and a hydrolysis time of 96 h. The experimental result showed that the maximum reducing sugar yield was 60.73% (53.35% higher than the wheat straw without NaOH pre-treatment), which is in accordance with the predicted conditions.

Download Full-text

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

Journal of Biobased Materials and Bioenergy ◽

10.1166/jbmb.2021.2062 ◽

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.

Download Full-text