Simultaneous saccharification and cofermentation

Figure 15.9 Block diagram for bioethanol from ligno-cellulosic biomass [27], CBP = consolidated biprocessing, CF = cofermetation, SSF = simultaneous saccharification and fermentation, SSCF = simultaneous saccharification and cofermentation. Components C = cellolose,...

The methods for fermentation of cellulose ethanol include direct and indirect fermentation, mixed strain fermentation, SSF, simultaneous saccharification and cofermentation (SSCF), nonisothermal SSF, and immobilized cell fermentation. 

BD (Yu et al., 1985a). Firstly, Clostridium thermocellum was induced to secrete extracellular endoglucanase (EC 3.2.1.4) and xylanase (EC 3.2.1.8) into the culture medium. K. pneumoniae was inoculated as a sequential culture for the rapid utilization of the accumulated sugars and formation of 2,3-BD. This approach was applicable to the use of mixed cellulose and hemicellulose substrates. To further reduce the production costs, co-utilization of both the cellulose and hemicellulose fractions to produce 2,3-BD could be accomplished by simultaneous saccharification and cofermentation process (Du et al., 2009 Ji et al., 2009b 2011). 

McMillan, J., M. Newman, D. Templeton and A. Mohagheghi (1999). Simultaneous saccharification and cofermentation of dilute-acid pretreated yellow poplar hardwood to ethanol using xylose-fermenting Zymomonas mobilis Applied Biochemistry and Biotechnology 79(1) 649-665. 

Cellulose hydrolysis and fermentation of sugar solution carried out in the same tank is referred to as SSF. Simultaneous saccharification of both cellulose (to glucose) and hemicellulose (to xylose and arabinose) and cofermentation of both glucose and xylose carried out by genetically engineered microbes that ferment xylose and glucose in the same broth is referred to as SSCF. 

Figure 2 An illustration of the various research activities underway to develop the next generation bioethanol plant. The 3 key areas of R D are in pretreatments, enzyme hydrolysis andfermentations. Significant efforts focus on process engineering cmd plant designs with the following at the core SHF -separate hydrolysis and fermentation, SSF - a simultaneous saccharification-fermentation, or SSCF - a simultaneous saccharification-cofermentation.

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