Simultaneous saccharification and fermentation

Emert Also known as the Gulf process, the University of Arkansas process, and SSF. A process for converting cellulose to ethanol by simultaneous saccharification and fermentation. Invented by G. H. Emert. 

Simultaneous saccharification and fermentation (SSF) one-stage enzymatic hydrolysis, but the fermentation of pentoses and hexoses takes place in separate process steps. 

Huang, L. R, Jin, B., Lant, R, Zhou, J. (2005b). Simultaneous saccharification and fermentation of potato starch wastewater to laetie aeid by Rhizopus oryzae and Rhizopus arrhizus. Biochem. Engg. J., 23,265-276. 

Jin, B., Huang, L. R, Lant, R. (2003). Rhizopus arrhizus - a producer for simultaneous saccharification and fermentation of starch waste materials to L(+)-lactic acid. Biotechnol. Lett., 25, 1983-1987. 

As mentioned in the biological—biochemical section, another approach to improve alcoholic fermentation combines saccharification and fermentation, ie, simultaneous saccharification and fermentation (SSF). Enzyme-catalyzed cellulose hydrolysis and fermentation to alcohol takes place in the same vessel in the presence of enzyme and yeast (50). Reduced fermenter pressures and enzyme and yeast recycling result in 70 to 80% ethanol yields. These process modifications, coupled with more energy-efficient distillation and heat exchanger improvements, are projected to make fermentation ethanol from low value biomass competitive with industrial ethanol (51). 

Index Entries Ammonia fiber explosion corn stover enzymatic hydrolysis simultaneous saccharification and fermentation moisture content residence time. 

Simultaneous saccharification and fermentation (SSF) experiments were conducted according to NREL standard protocol (LAP-008). Each SSF flask was loaded with 3% (w/w) glucan, 1% (w/v) yeast extract, 2% (w/v) peptone, 0.05 M citrate buffer (pH 4.8), the appropriate amount of cellulase enzyme to achieve 15 FPU/g of glucan, and the appropriate amount of Saccharomyces cerevisiae DSA (provided by NREL) inoculum (starting optical density of 0.5). The SSF flasks were equipped with water traps to maintain anaerobic conditions and were incubated at 37°C with gentle rotation (130 rpm) for a period of 168 h. 

Previous work has shown that it is possible to produce ethanol from alfalfa either by separate hydrolysis and fermentation (SHF) or simultaneous saccharification and fermentation (SSF). The yield of fermentable sugars from hydrolysis or saccharification is an important response variable in assessing the value of the feedstock. 

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,...

A very important step in the process is the simultaneous saccharification and fermentation. This requires enzymes that can effectively break the cellulosic and hemicellulosic material into sugar components. Additionally, micro-organisms that can use a wide range of sugars are desired. These are challenges to be solved by future research in the field of biotechnology. 

Simultaneous saccharification and fermentation (with inulinase-producing yeasts)... 

Wood, B. E., Aldrich, H. C., and Ingram, L. O. 1997. Ultrasound stimulates ethanol production during the simultaneous saccharification and fermentation of mixed waste office paper. Biotechnol. Prog., 13, 232-237. 

In addition to the variation among feedstocks, the requirements for fermenting microbes can differ with different pretreatment and fermentation processes. Currently, the most attractive process for biomass to biofuel conversion is simultaneous saccharification and fermentation (SSF), in which the hydrolytic enzymes and fermenting microbe(s) are mixed together and work under the same environment (Punnapayak and Emert, 1986). Use of SSF can mini-... 

Karimi, K., Emitiazi, G., and Taherzadeh, M. J. 2006. Ethanol production from dilute-acid pretreated rice straw by simultaneous saccharification and fermentation with Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. Enz Microbial Technol., 40,138-144. 

Ohta, K., Hamada, S., and Nakamura, T. 1993. Production of high concentrations of ethanol from inulin by simultaneous saccharification and fermentation using Aspergillus niger and Saccharomyces cerevisiae. App. Environ. Microbiol, 59, 729-733. 

The Gulf Oil Company developed a method called simultaneous saccharification and fermentation (SSF) for the enzymatic conversion of waste paper to ethanol.38 In this process the cellulose is enzymatically hydrolyzed and the glucose yeast-fermented in one operation. This modification, along with improved enzyme production and performance, has made the enzymatic technique more economically viable for the conversion of waste paper to ethanol. The process was donated to the University of Arkansas for further development. 

---