Simultaneous Saccharification-Fermentation

The a-amylase-treated hydrolysate is mixed with water to lower the soluble carbohydrate content to approximately 12°Plato and the temperature in preparation for simultaneous saccharification and fermentation. The temperature and pH are adjusted to 35°C and 5.5, respectively, and the FAN is adjusted to 150-200 mg. 

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Fig. 33.13. Simultaneous saccharification fermentation (SSF) and simultaneous saccharification and co-fermentation (SSCF) concepts.

Adaptive Control of the Simultaneous Saccharification - Fermentation Process from Starch to Ethanol... 

S. Ochoa, A. Yoo, J-U. Repke, G. Wozny and D.R. Yang. 2007, Modeling and Parameter Identification of the Simultaneous Saccharification-Fermentation Process for Ethanol Production, Biotechnol. Prog., 23, 1454-1462. 

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 termed simultaneous-saccharification-fermentation (SSF). 

The cellulose-to-ethanol process has five basic steps as shown in Figure I. They are feedstock handling and pretreatment, enzyme production, yeast production, simultaneous saccharification/fermentation (SSF) and ethanol recovery. Cellulose is the most abundant organic material on the earth. It is annually renewable, and not directly useful as a foodstuff. It is a polymer of glucose linked /8-1,4 as compared with the a-1,4 linked polymer starch which by contrast is easily digestible by man. There are three basic classes of potential cellulose feedstocks. These are agricultural by-products, industrial and municipal wastes, and special crops. The availability of these materials in the U.S. is shown in Table I. For economic reasons, we are concentrating our efforts on those materials that are collected for some other reason. 

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.

Effect of Pretreatment on Lactic Acid Fermentation of Bean Curd Refuse with Simultaneous Saccharification... 

Dry bean curd refuse was used as the substrate in the lactic acid fermentation with simultaneous saccharification (SSF). The dry bean curd refuse was preliminarily sieved under a mesh size of 250 II m. It contained 12.3% water, 4.0% ash, 0.8% lipid, 29.3% protein, 53.6% carbohydrate, respectively, in weight basis. The cellulase derived from Aspergilltis niger with an enzymatic activity of 25,000 units/g (Tokyo Kasei Industry Inc.) was employed as the saccharification enzyme. 

For lactic acid fermentation of bean curd refuse with simultaneous saccharification, it is found that the pretreatment of the substrate using 0.1 or 0.2 mol/l HCl aqueous solution with heating at niTi for 30 min efficiently solubilized the raw material and significantly enhanced the enzymatic saccharification followed by the lactic acid fermentation. The amount of initial load of bean curd refiise in dried state could be increased up to 75 g/1 in a batch fermentation, and the finally attained lactic acid yield and its concentration were as high as 87.0% and 45.8 g/1, respectively. 

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,...

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