scholarly journals Effects of Biosurfactants on Enzymatic Saccharification and Fermentation of Pretreated Softwood

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3559 ◽  
Author(s):  
Alfredo Oliva-Taravilla ◽  
Cristhian Carrasco ◽  
Leif J. Jönsson ◽  
Carlos Martín

The enzymatic hydrolysis of cellulose is inhibited by non-productive adsorption of cellulases to lignin, and that is particularly problematic with lignin-rich materials such as softwood. Although conventional surfactants alleviate non-productive adsorption, using biosurfactants in softwood hydrolysis has not been reported. In this study, the effects of four biosurfactants, namely horse-chestnut escin, Pseudomonas aeruginosa rhamnolipid, and saponins from red and white quinoa varieties, on the enzymatic saccharification of steam-pretreated spruce were investigated. The used biosurfactants improved hydrolysis, and the best-performing one was escin, which led to cellulose conversions above 90%, decreased by around two-thirds lignin inhibition of Avicel hydrolysis, and improved hydrolysis of pretreated spruce by 24%. Red quinoa saponins (RQS) addition resulted in cellulose conversions above 80%, which was around 16% higher than without biosurfactants, and it was more effective than adding rhamnolipid or white quinoa saponins. Cellulose conversion improved with the increase in RQS addition up to 6 g/100 g biomass, but no significant changes were observed above that dosage. Although saponins are known to inhibit yeast growth, no inhibition of Saccharomyces cerevisiae fermentation of hydrolysates produced with RQS addition was detected. This study shows the potential of biosurfactants for enhancing the enzymatic hydrolysis of steam-pretreated softwood.

RSC Advances ◽  
2014 ◽  
Vol 4 (69) ◽  
pp. 36591-36596 ◽  
Author(s):  
M. H. Sipponen ◽  
V. Pihlajaniemi ◽  
O. Pastinen ◽  
S. Laakso

24 h enzymatic hydrolysis (15 FPU g−1) of solid residues from wheat straw autohydrolysis. Cellulose conversion as a function of lignin content (left) or lignin surface area (right) in solid residues.


2019 ◽  
Vol 15 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Swapnil Gaikwad ◽  
Avinash P. Ingle ◽  
Silvio Silverio da Silva ◽  
Mahendra Rai

Background: Enzymatic hydrolysis of cellulose is an expensive approach due to the high cost of an enzyme involved in the process. The goal of the current study was to apply magnetic nanomaterials as a support for immobilization of enzyme, which helps in the repeated use of immobilized enzyme for hydrolysis to make the process cost-effective. In addition, it will also provide stability to enzyme and increase its catalytic activity. Objective: The main aim of the present study is to immobilize cellulase enzyme on Magnetic Nanoparticles (MNPs) in order to enable the enzyme to be re-used for clean sugar production from cellulose. Methods: MNPs were synthesized using chemical precipitation methods and characterized by different techniques. Further, cellulase enzyme was immobilized on MNPs and efficacy of free and immobilized cellulase for hydrolysis of cellulose was evaluated. Results: Enzymatic hydrolysis of cellulose by immobilized enzyme showed enhanced catalytic activity after 48 hours compared to free enzyme. In first cycle of hydrolysis, immobilized enzyme hydrolyzed the cellulose and produced 19.5 ± 0.15 gm/L of glucose after 48 hours. On the contrary, free enzyme produced only 13.7 ± 0.25 gm/L of glucose in 48 hours. Immobilized enzyme maintained its stability and produced 6.15 ± 0.15 and 3.03 ± 0.25 gm/L of glucose in second and third cycle, respectively after 48 hours. Conclusion: This study will be very useful for sugar production because of enzyme binding efficiency and admirable reusability of immobilized enzyme, which leads to the significant increase in production of sugar from cellulosic materials.


2013 ◽  
Vol 85 (17) ◽  
pp. 8121-8126 ◽  
Author(s):  
Britta Opitz ◽  
Andreas Prediger ◽  
Christian Lüder ◽  
Marrit Eckstein ◽  
Lutz Hilterhaus ◽  
...  

2015 ◽  
Vol 51 (52) ◽  
pp. 10502-10505 ◽  
Author(s):  
Aiping Chang ◽  
Qingshi Wu ◽  
Wenting Xu ◽  
Jianda Xie ◽  
Weitai Wu

The physical trapping of cellulose in microgels leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose.


1977 ◽  
Vol 23 (2) ◽  
pp. 139-147 ◽  
Author(s):  
D. Sternberg ◽  
P. Vuayakumar ◽  
E. T. Reese

The enzymatic conversion of cellulose is catalyzed by a multiple enzyme system. The Trichoderma enzyme system has been studied extensively and has insufficient β-glucosidase (EC 3.2.1.21) activity for the practical saccharification of cellulose. The black aspergilli (A. niger and A. phoenicis) were superior producers of β-glucosidase and a method for production of this enzyme in liquid culture is presented. When Trichoderma cellulase preparations are supplemented with β-glucosidase from Aspergillus during practical saccharifications, glucose is the predominant product and the rate of saccharification is significantly increased. The stimulatory effect of β-glucosidase appears to be due to the removal of inhibitory levels of cellobiose.


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