Saccharification

Dextrose yield, however, can be increased by conducting saccharification at a lower soHds level where the reverse reaction is minimized. Eor instance, dextrose yields of 98.8, 98.2, 97.5, and 96.9% dry basis can be achieved at soHds levels of 10, 15, 20, and 25%, respectively (10). Low soHds operation, however, is not used commercially owing to problems associated with microbial contamination and cost of water removal. Dextrose level can be increased by 0.5—1.5% at normal reaction soHds by using an enzyme such as puUulanase (11) or a B. megaterium amylase (12) in conjunction with... 

A. J. Panshia, Wood Saccharification in Porest Products, McGraw-HiU Book Co., Inc., New York, 1950, pp. 403—412. 

The pH has a great influence on the en2ymatic processes during mashing. Through water treatment it is possible to bring about shifts in pH whereby the transformations are decisively induenced. ( -Amylase has a pH optimum at 5.4, a-amylase at 5.8, and the normal mash has a pH of about 5.4 during saccharification. The induence of the concentration of the mash is such that thin mash increases the yield of both extract and maltose (Table 9). 

Conversion. Conversion describes the enzymatic starch hydrolysis processes, Hquification, and saccharification. 

The primary steps in the conversion of starch are Uquefaction, saccharification, and isomerization. By controlling the enzymatic reactions, sugars of different sweetness can be produced to suit the various needs of manufacturers of food and nonalcohoUc beverages. 

Eig. 10. Saccharification of starch using amyloglucoside (AMG) ( " ) with puUulanase (-----) without puUulanase. Initial dry substance (DS) of 28% at... 

The purification of saccharified starch depends on the raw material used, and may be different from plant to plant. When the starch slurry is hquefied ia a jet cooker the saccharification process is carried out at 55—65°C, pH 4—4.5, for 24—72 hours. The subsequent steps consist of filtration or centrifiigation, ion exchange, isomerization, treatment with activated carbon, and evaporation to form a storage-stable product. 

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). 

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. 

Bergius-Rheinau A saccharification process in which wood is hydrolyzed with concentrated hydrochloric acid to produce sugars for subsequent fermentation to ethanol. 

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. 

Madison An improved version of the Scholler-Tomesch saccharification process. Developed at the U.S. Forest Products Laboratory, Madison, WI. 

---