Saccharification of cellulose, enzymatic

Enzymatic Saccharification of Cellulose in Semi-and Continously Agitated Systems... 

Fig. 6. Glucose and cellobiose inhibition of enzymatic saccharification of cellulose. <25p cellulose (Solka Floe) in 10 ml tubes, agitated, O-O-O-O-control, A-A-A-A-control + 5mg/ml of cellobiose, - - -control +10 mg/ml of d-glucose. Reaction time —10 min. Temp. — 50° C, Cellulase —1.86 FP...

From the data on pure and crude cellulose saccharification presented in the paper it is evidenced that the initial enzymatic saccharification of cellulose is of pseudo first order and is therefore represented by... 

The enzymatic saccharification of cellulose is a product inhibited system. The Linewearer Burk model is ... 

Griggs AJ, Stickel JJ, Lischeske JJ. (2012a). A mechanistic model for enzymatic saccharification of cellulose using continuous distribution kinetics I depolymerization by EGI and CBHI. Biotechnol Bioeng, 109(3), 665-675. 

Henley R G, Yang R Y K, Greenfield P F, (1980), Enzymatic saccharification of cellulose in membrane reactors. Enzyme Microbial Technology, 2,206-208. 

Alfani, F., Albanesi, D., Cantarella, M., Scardi, V., Vetromile, A. (1982). Kinetics of enzymatic saccharification of cellulose in a fiat-membrane reactor. Biomass, 2, 245—253. 

Arantes and Saddler 2010 Baneijee et al. 2010 Gao et al. 2010 Moreira et al. 2011). The role of amorphogenesis in the initial stage of enzymatic saccharification of cellulose is to non-hydrolytically loosen or disrupt the cellulose fibril network (Arantes and Saddler 2010). 

Hatakka, A.I., 1983. Pretreatment of wheat straw hy white-rot fungi for enzymatic saccharification of cellulose. Applied Microbiology and Biotechnology 18, 350—357. 

Fermentation can be combined with other operations. For example, feedback inhibition of enzymatic hydrolysis of cellulose can be relieved by removal of the product glucose by fermentation as it forms. This is teni ed. simultaneou.s-saccharification-fermentation (SSF). 

Simultaneous saccharification and co-fermentation (SSCF) one-stage enzymatic hydrolysis of cellulose and fermentation of pentoses and hexoses all in one process step. The upstream hydrolysis of the hemicellulose takes place in a separate process step. 

Saccharification of cellulosic biomass by dilute acid has a much longer history than the enzymatic process. The initial acid-catalyzed wood saccharification was in operation in Germany as early as the 1940s (1). In recent... 

Enzyme activity loss because of non-productive adsorption on lignin surface was identified as one of the important factors to decrease enzyme effectiveness, and the effect of surfactants and non-catalytic protein on the enzymatic hydrolysis has been extensively studied to increase the enzymatic hydrolysis of cellulose into fermentable sugars [7, 9 19]. The reported study showed that the non-ionic surfactant poly(oxyethylene)2o-sorbitan-monooleate (Tween 80) enhanced the enzymatic hydrolysis rate and extent of newspaper cellulose by 33 and 14%, respectively [20]. It was also found that 30% more FPU cellulase activity remained in solution, and about three times more recoverable FPU activity could be recycled with the presence of Tween 80. Tween 80 enhanced enzymatic hydrolysis yields for steam-exploded poplar wood by 20% in the simultaneous saccharification and fermentation (SSF) process [21]. Helle et al. [22] reported that hydrolysis yield increased by as much as a factor of 7, whereas enzyme adsorption on cellulose decreased because of the addition of Tween 80. With the presence of poly(oxyethylene)2o-sorbitan-monolaurate (Tween 20) and Tween 80, the conversions of cellulose and xylan in lime-pretreated com stover were increased by 42 and 40%, respectively [23]. Wu and Ju [24] showed that the addition of Tween 20 or Tween 80 to waste newsprint could increase cellulose conversion by about 50% with the saving of cellulase loading of 80%. With the addition of non-ionic, anionic, and cationic surfactants to the hydrolysis of cellulose (Avicel, tissue paper, and reclaimed paper), Ooshima et al. [25] subsequently found that Tween 20 was the most effective for the enhancement of cellulose conversion, and anionic surfactants did not have any effect on cellulose hydrolysis. With the addition of Tween 20 in the SSF process for... 

The methods for saccharification of cellulose include acid saccharification and enzymatic saccharification. 

Application of scanning electron microscopy (SEM) allows the observation of appearance of fibres and their changes during the enzymatic degradation (see Fig. 4.20). As a result of the enzymatic degradation process for the polyester-cellulose fibrous blends, the degree of saccharification of cellulose fraction was achieved at a level up to 99 wt.%. 

The bioconversion of cellulose into ethanol with conventional methods is usually achieved in two steps first being the enzymatic saccharification of the polysaccharide to monosaccharide and secondly the bioconversion of monosaccharides into ethanol. A combination of enzymatic hydrolysis and ethanol production in the same reactor has been attempted using different cellulases and ethanol producing microbial species to improve process efficiency [46-53]. The production of ethanol from cellulose in a simultaneous saccharification and biological conversion process alleviates the problem of end product inhibition, since glucose does not accumulate in this system and is converted to ethanol immediately following saccharification [46]. 

Phflippidis, G.P., Smith, T.K., Wyman, C.E., 1993. Study of the enzymatic hydrolysis of cellulose for production of fuel ethanol by the simultaneous saccharification and fermentation process. Biotechnology and Bioengineering 41, 846-853. 

Yang, F. Li, L. Z. Li, Q. Tan, W. Liu, W. Xian, M. (2010). Enhancement of enzymatic in situ saccharification of cellulose in aqueous-ionic liquid media by ultrasonic intensification. Carboh. Polym., 81,311-316, ISSN 0144-8617. 

---