Pretreatment of wheat straw by nonionic surfactant-assisted dilute acid for enhancing enzymatic hydrolysis and ethanol production

AbstractThe addition of laccase enzymes reduces the amount of phenols present in lignocellulosic pretreated materials and increases their fermentability. However, laccase addition in combination with cellulases reduces hydrolysis yields. In this work, hybrid hydrolysis and fermentation (HHF) configuration allowed overcoming the negative effect of laccase treatment on enzymatic hydrolysis. Furthermore, the effects of different laccase dosages, length of detoxification time and inoculum size on ethanol production were evaluated. In the evaluated configurations, the different laccase dosages did not show any significant effect on enzymatic hydrolysis. The lowest laccase dosage (0.5 IU/g DW) removed ~70% of total phenols which was enough to reach the highest ethanol production yields (~10 g/L) using K. marxianus CECT 10875. Shorter detoxification times and larger inoculum sizes had a positive impact on both ethanol production and volumetric productivity. These optimal detoxification conditions enable the fermentation of inhibitory slurries by reducing the overall time and cost of the process.

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Combined steam-explosion toward vacuum and dilute-acid spraying of wheat straw. Impact of severity factor on enzymatic hydrolysis

Renewable Energy ◽

10.1016/j.renene.2015.01.038 ◽

2015 ◽

Vol 78 ◽

pp. 516-526 ◽

Cited By ~ 20

Author(s):

Maache-Rezzoug Zoulikha ◽

Maugard Thierry ◽

Zhao Jean-Michel Qiuyu ◽

Armelle Nouviaire ◽

Rezzoug Sid-Ahmed

Keyword(s):

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Steam Explosion ◽

Dilute Acid ◽

Severity Factor

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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.

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