Enzymatic and Chemical hydrolysis of certain cellulosic materials

Kassim, E. A.; El-Shahed, A. S.

doi:10.1016/0141-4607(86)90097-1

Cited by 14 publications

(5 citation statements)

References 4 publications

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“…The alkali pretreatment can result in a sharp increase in saccharification, with manifold yields (e.g. [ 130 ]). Pretreatment can be performed at low temperatures but with a relatively long time and high concentration of the base.…”

Section: Pretreatment Methods For Lignocellulose Wastesmentioning

confidence: 99%

Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

Taherzadeh

2008

IJMS

2,159

1,089

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Lignocelluloses are often a major or sometimes the sole components of different waste streams from various industries, forestry, agriculture and municipalities. Hydrolysis of these materials is the first step for either digestion to biogas (methane) or fermentation to ethanol. However, enzymatic hydrolysis of lignocelluloses with no pretreatment is usually not so effective because of high stability of the materials to enzymatic or bacterial attacks. The present work is dedicated to reviewing the methods that have been studied for pretreatment of lignocellulosic wastes for conversion to ethanol or biogas. Effective parameters in pretreatment of lignocelluloses, such as crystallinity, accessible surface area, and protection by lignin and hemicellulose are described first. Then, several pretreatment methods are discussed and their effects on improvement in ethanol and/or biogas production are described. They include milling, irradiation, microwave, steam explosion, ammonia fiber explosion (AFEX), supercritical CO 2 and its explosion, alkaline hydrolysis, liquid hot-water pretreatment, organosolv processes, wet oxidation, ozonolysis, dilute-and concentrated-acid hydrolyses, and biological pretreatments.

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Section: Pretreatment Methods For Lignocellulose Wastesmentioning

confidence: 99%

Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

Taherzadeh

2008

IJMS

2,159

1,089

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“…Alternatively, cassava pulp can be pretreated with steam or dilute acid or alkali to break down hemicelluloses and lignin. By breaking down the fiber or the lignocellulosic structure, which holds the starch granules inside, by suitable methods such as mechanical, chemical, and enzymatic treatments, higher glucose yields could be obtained [29,30].…”

Section: Enzymatic Hydrolysismentioning

confidence: 99%

Production of lactic acid and ethanol by Rhizopus oryzae integrated with cassava pulp hydrolysis

Thongchul

Navankasattusas

Yang

2009

Bioprocess Biosyst Eng

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Cassava pulp was hydrolyzed with acids or enzymes. A high glucose concentration (>100 g/L) was obtained from the hydrolysis with 1 N HCl at 121 degrees C, 15 min or with cellulase and amylases. While a high glucose yield (>0.85 g/g dry pulp) was obtained from the hydrolysis with HCl, enzymatic hydrolysis yielded only 0.4 g glucose/g dry pulp. These hydrolysates were used as the carbon source in fermentation by Rhizopus oryzae NRRL395. R. oryzae could not grow in media containing the hydrolysates treated with 1.5 N H2SO4 or 2 NH3PO4, but no significant growth inhibition was found with the hydrolysates from HCl (1 N) and enzyme treatments. Higher ethanol yield and productivity were observed from fermentation with the hydrolysates when compared with those from fermentation with glucose in which lactic acid was the main product. This was because the extra organic nitrogen in the hydrolysates promoted cell growth and ethanol production.

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“…It cannot be neglected that the cellulose can be degraded at acidic or alkaline solution [20,21]. Because of the acid hydrolysis of cellulose during acidic sulfite pretreatment, the increase in the glucan proportion was the lowest in all sulfite pretreatments.…”

Section: Resultsmentioning

confidence: 99%

Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue

Xing

et al. 2012

Biotechnol Biofuels

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BackgroundCorn cob residue (CCR) is a kind of waste lignocellulosic material with enormous potential for bioethanol production. The moderated sulphite processes were used to enhance the hydrophily of the material by sulfonation and hydrolysis. The composition, FT-IR spectra, and conductometric titrations of the pretreated materials were measured to characterize variations of the CCR in different sulfite pretreated environments. And the objective of this study is to compare the saccharification rate and yield of the samples caused by these variations.ResultsIt was found that the lignin in the CCR (43.2%) had reduced to 37.8%, 38.0%, 35.9%, and 35.5% after the sulfite pretreatment in neutral, acidic, alkaline, and ethanol environments, respectively. The sulfite pretreatments enhanced the glucose yield of the CCR. Moreover, the ethanol sulfite sample had the highest glucose yield (81.2%, based on the cellulose in the treated sample) among the saccharification samples, which was over 10% higher than that of the raw material (70.6%). More sulfonic groups and weak acid groups were produced during the sulfite pretreatments. Meanwhile, the ethanol sulfite treated sample had the highest sulfonic group (0.103 mmol/g) and weak acid groups (1.85 mmol/g) in all sulfite treated samples. In FT-IR spectra, the variation of bands at 1168 and 1190 cm-1 confirmed lignin sulfonation during sulfite pretreatment. The disappearance of the band at 1458 cm-1 implied the methoxyl on lignin had been removed during the sulfite pretreatments.ConclusionsIt can be concluded that the lignin in the CCR can be degraded and sulfonated during the sulfite pretreatments. The pretreatments improve the hydrophility of the samples because of the increase in sulfonic group and weak acid groups, which enhances the glucose yield of the material. The ethanol sulfite pretreatment is the best method for lignin removal and with the highest glucose yield.

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Enzymatic and Chemical hydrolysis of certain cellulosic materials

Cited by 14 publications

References 4 publications

Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

Pretreatment of Lignocellulosic Wastes to Improve Ethanol and Biogas Production: A Review

Production of lactic acid and ethanol by Rhizopus oryzae integrated with cassava pulp hydrolysis

Comparative study of sulfite pretreatments for robust enzymatic saccharification of corn cob residue

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