Characteristics Of Α-amylase Research Articles

UV mutagenesis for the overproduction of thermoalkali-stable α-amylase from Bacillus subtilis TLO3 by fermentation of stale bread: Potential application as detergent additive

The aims of this study were (1) to test different starch-rich wastes and different chemical pretreatments for α-amylase production by the strain Bacillus subtilis TLO3; (2) to investigate the possibility of using UV mutagenesis to improve the production and characteristics of α-amylase and (3) to investigate the possibility of its applications as additive to detergents. The results indicated that stale bread was the best substrate for α-amylase production (107.3 U/min ±0.001). A mutant strain was isolated by random mutagenesis using UV-irradiations with an overproduction of α-amylase up to 473.3 U/min ±0.03 against 100 U/min ±0.06 with the parental strain. The alkali pretreatment enhanced the production of α-amylase by the mutant (1526.31 U/min ±0.67), compared to the untreated substrate (473.3 U/min ±0.03). The precipitated α-amylase was thermostable and alkalistable with an optimum activity at 70 °C and pH 8, and showed high stability with laundry detergents. The wash performance tests indicated that the precipitated α-amylase was effective in cleaning different stains (tomato sauce, chocolate sauce, coffee and tea).

Purification and Partial Characterization of α-Amylase Produced by a Thermo-Halophilic Bacterium Isolate PLS 75

Bio-based industries require stable enzymes in a broad range of environmental conditions. Extremophiles have attracted more interests as the source of such enzymes, one of which is α-amylase. This study aimed to purify and characterize α-amylase produced by a thermo-halophilic bacterium PLS 75 isolated from underwater fumaroles. Ammonium sulfate precipitation results showed that the highest specific α-amylase activity (21.7 U/mg) obtained at 40-60% saturation level, with a purity of 7.7-fold of the crude extract with 16.2% yield. Further purification using DEAE Sepharose column chromatography increased the enzyme purity 11.1-fold of the crude extract with 7.1% yield. Specific activity after column chromatography purification was 31.3 U/mg. The pure enzyme had a low molecular weight of 14 kDa. The enzyme showed the highest activity at 80 °C and pH 5. The activity increased to 126% when in methanol, while decreased when in ethyl acetate and chloroform. The characteristics of α-amylase with low molecular weight, which was active in acidic condition, stable in polar and non-polar solvents, may be used for for specific industrial needs.

Microbial α-amylase: A biomolecular overview

α-Amylase is an important amylolytic enzyme participating in hydrolysis of starch, the most common carbohydrate in nature. Compared to plant and animal origins, microbial α-amylase is the most popular source of industrial α-amylase. As such, high productive and favourable α-amylases for wider range of applications are highly sought after demands. The expression of α-amylase is regulated by its structural gene, amyR, DegU-P, PrsA lipoprotein, cutinase and other similar flanking genes, components of gene expression regulatory systems, molecular chaperones and enzymes. Moreover, the characteristics of α-amylase are closely related to the structures of constitutive domains and conserved regions, particularly the functional regions such as Ca2+-binding sites, non-catalytic carbohydrate-binding modules and surface-binding sites. Recent production of α-amylase based on genetic engineering and academic researches focused on mechanisms of catalysis greatly benefit from these biomolecular studies. Despite rapid developments, no reviews have systematically summarized these fundamental biomolecular studies. This review outlines microbial α-amylase at gene and structure levels by covering these significant aspects. The computer analytical tools are also reported, especially frequently used databases. A deeper understanding of the biomolecular basis of microbial α-amylase will significantly pave greater opportunities for industrial α-amylase and open our minds towards its related or even other enzymes.

Characteristics of α-Amylase during Germination of Two High-Sugar Sweet Corn Cultivars of Zea mays L.

The role of the scutellum and the aleurone in alpha-amylase production in the high-sugar sweet corn cultivars Illini X-tra Sweet (shrunken-2, sh2) and Illinois 677a (sugary, sugary enhancer; su se) was compared to that in the starchy (Su) hybrid Funks G4646 with the use of alpha-amylase enzyme assays, isoelectric focusing, electron microscopy, and laser scanning confocal microscopy. The scutellum of Illinois 677a had low levels of alpha-amylase activity compared to that of Funks G4646 through 10 days after imbibition, and the aleurone of Illini X-tra Sweet had negligible activity. On the isoelectric focusing gels, the Illinois 677a scutellum had fewer alpha-amylase isozymes at 7 days compared to the Funks G4646 scutellum. The Illini X-tra Sweet aleurone had no alpha-amylase isozymes. Funks G4646 scutellar epithelial and aleurone cells contained abundant rough endoplasmic reticulum, polysomes, and dictyosomes at 5 and 7 days, respectively. The scutellar epithelial cells of Illinois 677a contained fewer of these structures by 5 days, and the Illini X-tra Sweet aleurone contained mostly lipid bodies through 7 days. Few cytoplasmic membranes and little RNA were detected with laser scanning confocal microscopy in the Illini X-tra Sweet aleurone compared to Funks G4646 at 7 days. These data suggest that the scutellum of Illinois 677a and the aleurone of Illini X-tra Sweet have impaired abilities to produce alpha-amylase.