Alkali pretreatment of wheat straw followed by microbial hydrolysis for bioethanol production

2017 ◽  
Vol 40 (9) ◽  
pp. 1203-1211 ◽  
Author(s):  
Bahiru Tsegaye ◽  
Chandrajit Balomajumder ◽  
Partha Roy
Bioethanol ◽  
2016 ◽  
Vol 2 (1) ◽  
Author(s):  
María García-Torreiro ◽  
Miguel Álvarez Pallín ◽  
María López-Abelairas ◽  
Thelmo A. Lu-Chau ◽  
Juan M. Lema

AbstractBioconversion of lignocellulosic materials into ethanol requires an intermediate pretreatment step for conditioning biomass. Sugar yields from wheat straw were previously improved by the addition of a mild alkali pretreatment step before bioconversion by the white-rot fungus Irpex lacteus. In this work, an alternative alkaline treatment, which significantly reduces water consumption, was implemented and optimized. Sugar recovery increased 117% with respect to the previously developed alkaline wash process at optimal process conditions (30°C, 30 minutes and 35.7% (w/w) of NaOH). In order to further reduce operational costs, a system for alkali recycling was implemented. This resulted in the treatment of 150% more wheat straw using the same amount of NaOH. Finally, enzymatic hydrolysis was optimized and resulted in a reduction of enzyme dose of 33%.


2014 ◽  
Vol 20 (2) ◽  
pp. 261-271 ◽  
Author(s):  
Maryam Nikzad ◽  
Kamyar Movagharnejad ◽  
Farid Talebnia ◽  
Ghasem Najafpour ◽  
Farahi Hosein

Bioethanol production from lignocellulosic biomass provides an alternative energy-production system. Sorghum bicolor stem is a cheap agro-waste for bioethanol production. In this study, response surface methodology (RSM) was used to optimize alkali pretreatment conditions for sorghum bicolor stem with respect to substrate concentration, NaOH concentration and pretreatment time based on a central composite rotary design. The main goal was to achieve the highest glucose and xylose yields after enzymatic hydrolysis. Under optimum conditions of pretreatment i.e. time 60.4 min, solid loading 4.2%, and NaOH concentration 1.7%, yields of 98.94% g glucose/g cellulose and 65.14% g xylose/g hemicelluloses were obtained. The results of a confirmation experiment under the optimal conditions agreed well with model predictions. Pretreatment of sorghum bicolor stem at the optimum condition increased the glucose and xylose yields by 7.14 and 3.02 fold, respectively. Alkali pretreatment showed to be a great choice for the pretreatment of sorghum bicolor stem.


2020 ◽  
pp. 103-110
Author(s):  
Larysa Sablii ◽  
Oleksandr Obodovych ◽  
Vitalii Sydorenko ◽  
Tamila Sheyko

This paper presents the results of studies of isolation lignin and hemicelluloses efficiency during the pre-treatment of wheat straw for hydrolysis in a rotary-pulsation apparatus. The pre-treatment of lignocellulosic raw materials for hydrolysis is a necessary step in the second-generation bioethanol production technology. The lignocellulose complex is destroyed during this process, and this allows hydrolytic enzymes access to the surface of cellulose fibers. The pre-treatment is the most energy-consuming stage in bioethanol production technology, since it usually occurs at high temperature and pressure for a significant time. One of the ways to improve the efficiency of this process is the use of energy-efficient equipment that allows intensifying heat and mass transfer. An example of such equipment is a rotary-pulsation apparatus, which are effective devices in stirring, homogenization, dispersion technologies, etc. The treatment of wheat straw in a rotary-pulsation apparatus was carried out under atmospheric pressure without external heat supply at solid/water ratios of 1:10 and 1:5 in the presence of alkali. It was determined that the treatment of the water dispersion of straw at ratio of 1:10 due to the energy dissipation during 70 minutes leads to the release of 42 % of lignin and 25.76 % of easily hydrolyzed polysaccharides. Changing the solid / water ratio from 1:10 to 1:5 leads to an increase in the yield of lignin and easily hydrolyzed polysaccharides to 58 and 33.38 %, respectively.


2013 ◽  
Vol 59 (No. 12) ◽  
pp. 537-542 ◽  
Author(s):  
K. Jaisamut ◽  
L. Paulová ◽  
P. Patáková ◽  
M. Rychtera ◽  
K. Melzoch

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.


2016 ◽  
Vol 7 (6) ◽  
pp. 1389-1396 ◽  
Author(s):  
Muhammad Irfan ◽  
Umar Asghar ◽  
Muhammad Nadeem ◽  
Rubina Nelofer ◽  
Quratulain Syed ◽  
...  

3 Biotech ◽  
2012 ◽  
Vol 3 (5) ◽  
pp. 365-372 ◽  
Author(s):  
Shilpi Thakur ◽  
Bhuvnesh Shrivastava ◽  
Snehal Ingale ◽  
Ramesh C. Kuhad ◽  
Akshaya Gupte

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