High yield biorefinery products from sugarcane bagasse: Prebiotic xylooligosaccharides, cellulosic ethanol, cellulose nanofibrils and lignin nanoparticles

Sugarcane bagasse (SB) is made up of cellulose (32-43%), hemicellulose (19-34%) and lignin (14-30%). Due to high recalcitrant nature of SB, pretreatment is required to deconstruct its structure and enrich the cellulosic fraction. A two-stage NaOH and maleic acid pretreatment was applied to SB to enrich its cellulosic fraction. SB used in the present study is composed of cellulose (40.4 wt%), hemicellulose (20.9 wt%), lignin (22.5 wt%) and ash (4.0 wt%). After one-stage NaOH pretreatment, its cellulosic fraction increased to 61.8 wt% and later increased to 80.1 wt% after the second-stage acid pretreatment. Lignin fraction decreased to 3.0 wt% after one-stage NaOH pretreatment and remained unaffected after the acid pretreatment step. Hemicellulose fraction decreased substantially after the second-stage pretreatment with maleic acid. Pretreated SB displayed high crystallinity index and improved enzymatic digestibility. Hydrolysates of pretreated SB contained very low amount of xylose and subsequent fermentation by Saccharomyces cerevisiae -IQAr/45-1 resulted to ethanol level of 8.94 g/L. Maximal ethanol yield of 0.49 g/g (95.8% of theoretical yield) and productivity of 0.28 g/L/h was attained. At the same time, biomass yield and productivity of 0.47 g/g and 0.27 g/L/h respectively were obtained. Two-stage NaOH and maleic acid pretreatment led to ~ two-fold increase in cellulosic fraction and enhanced the enzymatic digestibility of SB up to 70.4%. The resulted enzymatic hydrolysate was efficiently utilized by S. cerevisiae -IQAr/45-1 to produce high yield of ethanol. Thus, optimization of enzymatic hydrolysis at low enzyme loading is expected to further improve the process and reduce cost.

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Production of Cellulosic Ethanol from Enzymatically Hydrolysed Wheat Straws

Applied Sciences ◽

10.3390/app10217638 ◽

2020 ◽

Vol 10 (21) ◽

pp. 7638

Author(s):

Vasile-Florin Ursachi ◽

Gheorghe Gutt

Keyword(s):

Enzymatic Hydrolysis ◽

Wheat Straw ◽

Cellulosic Ethanol ◽

Raw Material ◽

High Yield ◽

Liquid Ratio ◽

Hydrolysis Process ◽

Pretreatment Conditions ◽

Pretreated Wheat Straw ◽

First Time

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).

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Co-production of xylo-oligosaccharides, xylose and cellulose nanofibrils from sugarcane bagasse

Journal of Biotechnology ◽

10.1016/j.jbiotec.2020.07.001 ◽

2020 ◽

Vol 321 ◽

pp. 35-47

Author(s):

Wilian F. Marcondes ◽

Adriane M.F. Milagres ◽

Valdeir Arantes

Keyword(s):

Sugarcane Bagasse ◽

Cellulose Nanofibrils

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Production of cellulosic ethanol from sugarcane bagasse by steam explosion: Effect of extractives content, acid catalysis and different fermentation technologies

Bioresource Technology ◽

10.1016/j.biortech.2016.02.085 ◽

2016 ◽

Vol 208 ◽

pp. 184-194 ◽

Cited By ~ 54

Author(s):

P.V. Neves ◽

A.P. Pitarelo ◽

L.P. Ramos

Keyword(s):

Sugarcane Bagasse ◽

Cellulosic Ethanol ◽

Steam Explosion ◽

Acid Catalysis

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High-Yield Endoglucanase Production by Trichoderma harzianum IOC-3844 Cultivated in Pretreated Sugarcane Mill Byproduct

Enzyme Research ◽

10.4061/2010/854526 ◽

2010 ◽

Vol 2010 ◽

pp. 1-8 ◽

Cited By ~ 22

Author(s):

Aline Machado de Castro ◽

Marcela Costa Ferreira ◽

Juliana Cunha da Cruz ◽

Kelly Cristina Nascimento Rodrigues Pedro ◽

Daniele Fernandes Carvalho ◽

...

Keyword(s):

Trichoderma Harzianum ◽

Cellulosic Ethanol ◽

Low Cost ◽

Xylanase Activity ◽

Cellulose Hydrolysis ◽

High Yield ◽

Endoglucanase Activity ◽

Crude Enzyme Extract ◽

Mild Conditions ◽

Pretreated Sugarcane Bagasse

The low-cost production of cellulolytic complexes presenting high action at mild conditions and well-balanced cellulase activities is one of the major bottlenecks for the economical viability of the production of cellulosic ethanol. In the present paper, the filamentous fungus Trichoderma harzianum IOC-3844 was used for the production of cellulases from a pretreated sugarcane bagasse (namely, cellulignin), by submerged fermentation. This fungal strain produced high contents of endoglucanase activity (6,358 U·L−1) after 72 hours of process, and further relevant β-glucosidase and FPase activities (742 and 445 U·L−1, resp.). The crude enzyme extract demonstrated appropriate characteristics for its application in cellulose hydrolysis, such as high thermal stability at up to 50∘C, accessory xylanase activity, and absence of proteolytic activity towards azocasein. This strain showed, therefore, potential for the production of complete cellulolytic complexes aiming at the saccharification of lignocellulosic materials.

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