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Tapioca (cassava) crop of tropical America, is the fourth most important crop in tropical regions. Many provinces in southern China has planted. Cassava adaptability, drought resistance and barren. Therefore, in the Chinese tapioca starch is a starch raw material of good food and fermentation industries. The tapioca starch is amylose (20 ± 5%) and amylopectin (80 ± 5%) composed of the two starches can be enzyme hydrolysis (either the purified enzyme or an enzyme produced by a microorganism) into glucose or dextrin. Amylases are a class of widely exist in the enzymes of the microorganism, there are α-amylase and glucoamylase enzyme. Wherein the α-amylase is an endo-enzyme may be the hydrolysis of the starch in the α-4 glycosidic bond, the glucoamylase is a exonuclease mainly act on the starch in the α-1, 4 glycosidic bond, but in several recent years found many microorganisms glucoamylase can also act on the starch in the α-1, 6 glycosidic bond, it can be successively cut from the non-reducing end of the starch for a single molecule of glucose. We found that, the terrestrial buckle the capsule lAMINATING yeast (Saccharomycopsis fibuligera) can produce a high activity of amylase, while hydrolysis of α-1, 4 and α-1, 6 - glycosidic linkage capability, very suitable for the hydrolyzed tapioca starch. Our laboratory has been a of S. fibuligera strain A11 fermentation conditions optimized First, we take advantage of the surface response (Response Surface Methodology, RSM) to its solid state fermentation conditions were optimized design to obtain the final optimal conditions for the humidity of 61.5% (v / v), the ratio of substrate (rice husk: wheat bran) 0.42, starch, 2.0% (w / v), the vaccination the amount of 2.0% (v / v), and cultured at 28 ° C and natural pH amylase enzyme; under optimal conditions, the A11 strain the solid fermentation reach the 4296U / g in 120h the RSM predicted activity 4222U/dgs. Then, we use the immobilization technology to strain liquid fermentation of S. fibuligera amylase has been optimized for the PVA concentration of 8% (v / v) to give a final immobilization conditions, the sodium alginate concentration to 2.0% (w / v) , CaCl2 concentration of 3.0% (w / v), the initial inoculum of 5.0% (v / v), and immobilized time of 4h. The highest activity of up to 329 U / ml, the highest activity of free cells 244U/ml. On the basis of the above experiments, the further use of the amylase produced by S. fibuligera strains A11 and deposited in this laboratory strains of a Saccharomyces cerevisiae WO, tapioca starch as substrate, saccharification and fermentation alcohol production test, the end of fermentation obtained after the alcohol concentration of 10.5% (v / v).
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