Showing papers on "Amylase published in 2013"
TL;DR: The influence of biomacromolecular physical structure on the kinetics of degradation with exo-acting or a mixture of endo- and ex-acting enzymes was studied using three physical forms of maize and potato starch, amyloglucosidase (exo- acting) and α-amylase (endo-acting) as exemplars.
155 citations
TL;DR: Hydroponic studies showed that the superoxide dismutase activity and malondialdehyde level, which had been increased in the presence of metal stress in rice roots, were lowered by the bacterial inoculation.
Abstract: The present study demonstrates the metal toxicity ameliorating and growth promoting abilities of three different bacterial isolates when applied to rice as host plant. The three bacterial strains included a cadmium resistant Ochrobactrum sp., a lead resistant Bacillus sp. and an arsenic resistant Bacillus sp. designated as CdSP9, PbSP6, and AsSP9, respectively. When these isolates were used as inocula applied to metal-treated rice plants of variety Satabdi, the germination percentage, relative root elongation (RRE), amylase and protease activities were increased. The toxic effect of metal was reduced in presence of these bacteria. The overall biomass and root/shoot ratio were also enhanced by bacterial inoculation. Hydroponic studies showed that the superoxide dismutase (SOD) activity and malondialdehyde (MDA) level, which had been increased in the presence of metal stress in rice roots, were lowered by the bacterial inoculation. In addition, all three strains were 1-aminocyclopropane-1-carboxylate (ACC) deaminase and catalase positive, whereas siderophore producing ability was lacking in PbSP6. However, both PbSP6 and AsSP9 were protease positive and could hydrolyse starch. The data indicate that these bacteria have promise for bioremediation as well as for plant growth promotion.
152 citations
TL;DR: Scanning electron micrographs observation and particle size analysis revealed that the most important mechanism for the enzyme treatment of sludge might be solubilization of extracellular polymeric substances.
152 citations
TL;DR: The saliva, gastric and intestinal digestion of polysaccharide from Plantago asiatica L. seeds was investigated in vitro and it was found that salivary amylase had no effect on the poly Saccharide; however, the poly saccharide was influenced in later gastrointestinal digestion.
142 citations
TL;DR: Enzyme production was induced by a variety of starchy substrate but corn flour was found to be a suitable natural source for maximum production and Tryptone and ammonium nitrate as nitrogen sources gave higher yield compared to other nitrogen sources.
Abstract: Amylases are one of the most important enzymes in present-day biotechnology. The present study was concerned with the production and partial characterization of extracellular amylase from Bacillus amyloliquefaciens P-001. The effect of various fermentation conditions on amylase production through shake-flask culture was investigated. Enzyme production was induced by a variety of starchy substrate but corn flour was found to be a suitable natural source for maximum production. Tryptone and ammonium nitrate (0.2%) as nitrogen sources gave higher yield compared to other nitrogen sources. Maximum enzyme production was obtained after 48 hrs of incubation in a fermentation medium with initial pH 9.0 at 42°C under continuous agitation at 150 rpm. The size of inoculum was also optimized which was found to be 1% (v/v). Enzyme production was 2.43 times higher after optimizing the production conditions as compared to the basal media. Studies on crude amylase revealed that optimum pH, temperature and reaction time of enzyme activity was 6.5, 60°C and 40 minutes respectively. About 73% of the activity retained after heating the crude enzyme solution at 50°C for 30 min. The enzyme was activated by Ca2+ (relative activity 146.25%). It was strongly inhibited by Mn2+, Zn2+ and Cu2+, but less affected by Mg2+ and Fe2+.
133 citations
01 Jan 2013
TL;DR: Fungal enzymes are used in food, beverages, confectionaries, textiles and leather industries to simplify the processing of raw materials and are often more stable than enzymes derived from other sources.
Abstract: Endophytic fungi exhibit a complex web of interactions with host plants and have been extensively studied over the last several years as prolific sources of new bioactive natural products. Fungal enzymes are one of them which are used in food, beverages, confectionaries, textiles and leather industries to simplify the processing of raw materials. They are often more stable than enzymes derived from other sources. Enzymes of the endophytes are degraders of the polysaccharides available in the host plants. The use of simpler solid media permits the rapid screening of large populations of fungi for the presence or absence of specific enzymes. Fifty fungal strains, isolated from medicinal plants (Alpinia calcarata, Bixa orellana, Calophyllum inophyllum and Catharanthus roseus) were screened for extracellular enzymes such as amylase, cellulase, laccase, lipase, pectinase and protease on solid media. Sixty four percent of fungi screened for enzymes showed positive for lipase, 62% for amylase and pectinase, 50% showed for lipase, 32% showed for cellulase, 30% for laccase and only 28% showed positive for protease. The array of enzymes produced differs between fungi and often depends on the host and their ecological factors.
131 citations
TL;DR: In general, larger and more complex tannins, such as those in pomegranate and cranberry, more effectively inhibited the enzymes than did less polymerized cocoa tann Ins, and interaction of the tannin with the enzymes was confirmed through calorimetric measurements of changes in enzyme thermal stability.
Abstract: Proanthocyanidins and ellagitannins, referred to as “tannins”, exist in many plant sources. These compounds interact with proteins due to their numerous hydroxyl groups, which are suitable for hydrophobic associations. It was hypothesized that tannins could bind to the digestive enzymes α-amylase and glucoamylase, thereby inhibiting starch hydrolysis. Slowed starch digestion can theoretically increase satiety by modulating glucose “spiking” and depletion that occurs after carbohydrate-rich meals. Tannins were isolated from extracts of pomegranate, cranberry, grape, and cocoa and these isolates tested for effectiveness to inhibit the activity of α-amylase and glucoamylase in vitro. The compositions of the isolates were confirmed by NMR and LC/MS analysis, and tannin–protein interactions were investigated using relevant enzyme assays and differential scanning calorimetry (DSC). The results demonstrated inhibition of each enzyme by each tannin, but with variation in magnitude. In general, larger and more com...
127 citations
TL;DR: The properties of α-glucanotransferases are reviewed and the emerging use of these enzymes in the generation of novel starch derivatives is discussed, which is an agricultural raw material used in many food and industrial products.
118 citations
TL;DR: In this article, two pure bacterial strains were jointly applied as mixed cultures in a single fermenter, thus combining the starch hydrolysis process and H 2 production process, and the H 2 yield of pre-treated corn starch reached 1.19% higher than that of untreated corn starch.
113 citations
TL;DR: ADP-Glc pyrophosphorylase (AGPase) is identified as a key enzyme for starch accumulation in kiwifruit berries, as high-starch genotypes had 2- to 5-fold higher AGPase activity, which was maintained over a longer period of time and was also associated with enhanced and extended transcription of the AGPases large subunit 4 (APL4).
Abstract: Tomato, melon, grape, peach, and strawberry primarily accumulate soluble sugars during fruit development. In contrast, kiwifruit (Actinidia Lindl. spp.) and banana store a large amount of starch that is released as soluble sugars only after the fruit has reached maturity. By integrating metabolites measured by gas chromatography–mass spectrometry, enzyme activities measured by a robot-based platform, and transcript data sets during fruit development of Actinidia deliciosa genotypes contrasting in starch concentration and size, this study identified the metabolic changes occurring during kiwifruit development, including the metabolic hallmarks of starch accumulation and turnover. At cell division, a rise in glucose (Glc) concentration was associated with neutral invertase (NI) activity, and the decline of both Glc and NI activity defined the transition to the cell expansion and starch accumulation phase. The high transcript levels of β -amylase 9 (BAM9) during cell division, prior to net starch accumulation, and the correlation between sucrose phosphate synthase (SPS) activity and sucrose suggest the occurrence of sucrose cycling and starch turnover. ADP-Glc pyrophosphorylase (AGPase) is identified as a key enzyme for starch accumulation in kiwifruit berries, as high-starch genotypes had 2- to 5-fold higher AGPase activity, which was maintained over a longer period of time and was also associated with enhanced and extended transcription of the AGPase large subunit 4 (APL4). The data also revealed that SPS and galactinol might affect kiwifruit starch accumulation, and suggest that phloem unloading into kiwifruit is symplastic. These results are relevant to the genetic improvement of quality traits such as sweetness and sugar/acid balance in a range of fruit species.
103 citations
TL;DR: Tannin extracts both reduced and enhanced amylase activity depending on conditions, and, while these trends were clear in extracts, the effects on starch digestion in wholegrain flours was more complex.
Abstract: The purpose of this study was to investigate the effects of tannins on starch digestion in tannin-containing sorghum extracts and wholegrain flours from 12 sorghum varieties. Extracts reduced amylase activity in a tannin concentration-dependent manner when the extract was mixed with the enzyme before substrate (amylopectin) addition, with higher molecular weight tannins showing greater reduction. Conversely, when the extract and substrate were combined before enzyme addition an enhancement in amylase activity was experienced. In uncooked, cooked, and cooked and stored wholegrain sorghum flours, rapidly digestible, slowly digestible, and resistant starches were not correlated with tannin content or molecular weight distribution. Resistant starch increased from 6.5% to 22–26% when tannins were added to starch up to 50% (starch weight). Tannin extracts both reduced and enhanced amylase activity depending on conditions, and, while these trends were clear in extracts, the effects on starch digestion in wholegr...
TL;DR: Results show that phosphate limitation may be the mechanism to stimulate the lipid accumulation and removals of COD, total soluble nitrogen and total soluble phosphorus up to 91%, 98% and 97% were achieved, respectively.
01 Jan 2013
TL;DR: It can be concluded that aqueous extract of Morinda lucida exhibited the best inhibitory activity on the two enzymes studied and the presence of phytochemicals like flavonoids, saponins, and tannins may have contributed greatly to the inhibitoryactivity of the plant extract.
Abstract: Diabetes mellitus is a metabolic disorder of glucose metabolism. The management of blood glucose level is the hallmark in the treatment of this disease. This may be achieved through the use of oral hypoglycemic drugs such as biguanides, insulin secretagogues, and α-glucosidase inhibitors. The purpose of the present study was to investigate the inhibitory effect of Morinda lucida leaf extracts on the activities of α-amylase and α-glucosidase. This was performed using α-amylase from Aspergillus oryzae and α-glucosidase from Saccharomyces cerevisiae. Aqueous extract of Morinda lucida gave the highest percentage yield (9.99%) of the plant out of the three extracts (compared to acetone and ethanolic extracts) and possesses the highest inhibitory activity against α-amylase (IC50 value of 2.30 mg/mL) and α-glucosidase (IC50 value of 2.00 mg/mL). Kinetic analysis revealed that the aqueous extract of this plant leaf inhibited the α-amylase competitively but displayed mixed noncompetitive mode of inhibition towards α-glucosidase. It can be concluded that aqueous extract of Morinda lucida exhibited the best inhibitory activity on the two enzymes studied and the presence of phytochemicals like flavonoids, saponins, and tannins may have contributed greatly to the inhibitory activity of the plant extract.
TL;DR: It is suggested that the inhibition of carbohydrate digestive enzymes and their phenolic content may contribute to the anti‐hyperglycaemic effects of pomegranate flower and peel, and support their claims in diabetes.
Abstract: Pomegranate has been documented for the management of diabetes in Unani and Chinese medicine. This study compared the effects of the extracts of different pomegranate parts, including juice, peels, seeds and flowers, on carbohydrate digestive enzymes (α-amylase and α-glucosidase) in vitro. The methanolic flower extract inhibited α-amylase and α-glucosidase, while the methanolic peel extract inhibited α-glucosidase selectively. The most active flower extract was subjected to water-ethyl acetate partition. The ethyl acetate fraction was more potent than the water fraction in inhibiting both enzymes. Gallic acid and ellagic acid also showed selective inhibition against α-glucosidase, and their presence in the ethyl acetate fraction was confirmed by HPLC-DAD and HPLC-HESI-MS. Our findings suggest that the inhibition of carbohydrate digestive enzymes and their phenolic content may contribute to the anti-hyperglycaemic effects of pomegranate flower and peel, and support their claims in diabetes.
TL;DR: Results suggest that the endogenous cellulase is far from sufficient to fully digest the ingested fiber, so cellulase should be developed as a kind of aquatic additive.
Patent•
03 Jun 2013
TL;DR: The variant alpha-amylases are useful for starch liquefaction and saccharification, for cleaning starchy stains in laundry, dishwashing, and other applications, for textile processing (e.g., desizing), in animal feed for improving digestibility, and for baking and brewing as discussed by the authors.
Abstract: Disclosed are compositions and methods relating to variant alpha-amylases. The variant alpha-amylases are useful, for example, for starch liquefaction and saccharification, for cleaning starchy stains in laundry, dishwashing, and other applications, for textile processing (e.g., desizing), in animal feed for improving digestibility, and for baking and brewing.
TL;DR: This study suggests that the ethanolic extract of Shirishadi polyherbal compound effectively acts as alpha amylase and glucosidase inhibitor leading to a reduction in starch hydrolysis and hence acts as antiasthmatic as well as hypoglycemic drug.
Abstract: Asthma and diabetes have strong relationship; both are cause and effect of each other. Oxidative stress due to bronchial asthma may cause insulin resistance whereas lack of proper insulin can cause defective smooth muscle relaxant. There is no single medicine available that can manage both diseases, rather the mainstay treatment of bronchial asthma causes hyperglycemia. Keeping this problem in focus, in this study the hypoglycemic effect of an indigenous antiasthmatic Ayurvedic drug Shirishadi was evaluated. Pancreatic alpha amylase and glucosidase inhibitors offer an effective strategy to lower the level of post prandial hyperglycemia via control of starch breakdown. For evaluation of hypoglycemic activity of drug, in-vitro alpha amylase and alpha glucosidase enzyme inhibition was calculated. Ethanolic extract of compound showed 76.40% + 0.88% reduction in alpha amylase activity and 63.85% + 0.36% in alpha glucosidase activity with IC50 0.68 mg/ml and 2.89 mg/ml, respectively. This study suggests that the ethanolic extract of Shirishadi polyherbal compound effectively acts as alpha amylase and glucosidase inhibitor leading to a reduction in starch hydrolysis and hence acts as antiasthmatic as well as hypoglycemic drug.
TL;DR: It is found that AtAMY3 has unique properties among other characterized plant α-amylases, with a pH optimum of 7.5–8, appropriate for activity in the chloroplast stroma, and is a redox-regulated enzyme.
TL;DR: An optimization strategy, based on statistical experimental design, is employed to enhance the production of thermostable α-amylase by a thermotolerant B. licheniformis AI20 isolate, which showed great stability against different solvents and was slightly inhibited by detergents, sodium dodecyl sulphate, or chelating agents.
Abstract: An optimization strategy, based on statistical experimental design, is employed to enhance the production of thermostable α-amylase by a thermotolerant B. licheniformis AI20 isolate. Using one variant at time (OVAT) method, starch, yeast extract, and CaCl2 were observed to influence the enzyme production significantly. Thereafter, the response surface methodology (RSM) was adopted to acquire the best process conditions among the selected variables, where a three-level Box-Behnken design was employed to create a polynomial quadratic model correlating the relationship between the three variables and α-amylase activity. The optimal combination of the major constituents of media for α-amylase production was 1.0% starch, 0.75% yeast extract, and 0.02% CaCl2. The predicted optimum α-amylase activity was 384 U/mL/min, which is two folds more than the basal medium conditions. The produced α-amylase was purified through various chromatographic techniques. The estimated enzyme molecular mass was 55 kDa and the α-amylase had an optimal temperature and pH of 60–80°C and 6–7.5, respectively. Values of and for the purified enzyme were 454 mU/mg and 0.709 mg/mL. The α-amylase enzyme showed great stability against different solvents. Additionally, the enzyme activity was slightly inhibited by detergents, sodium dodecyl sulphate (SDS), or chelating agents such as EDTA and EGTA. On the other hand, great enzyme stability against different divalent metal ions was observed at 0.1 mM concentration, but 10 mM of Cu2
TL;DR: In this paper, an α-amylase is immobilized, using glutaraldehyde, onto magnetite nanoparticles prepared using gum acacia as the steric stabilizer (GA-MN), for the first time.
Abstract: In this work, α-amylase is immobilized, using glutaraldehyde, onto magnetite nanoparticles prepared using gum acacia as the steric stabilizer (GA-MN), for the first time. The immobilization of amylase to GA-MN is very fast and the synthesis of GA-MN is very simple. The use of GA enables higher immobilization of α-amylase (60%), in contrast to the unmodified magnetite nanoparticles (∼20%). The optimum pH and temperature for maximum enzyme activity for the immobilized amylase are identified to be 7.0 and 40 °C, respectively, for the hydrolysis of starch. The kinetic studies confirm the Michaelis–Menten behavior and suggests overall enhancement in the performance of the immobilized enzyme with reference to the free enzyme. Similarly the thermal stability of the enzyme is found to increase after the immobilization. The GA-MN bound amylase has also been demonstrated to be capable of being reused for at least six cycles while retaining ∼70% of the initial activity. By using a magnetically active support, quick separation of amylase from reaction mixture is enabled. The catalytic rate of amylase is actually found to enhance by twofold after the immobilization, which is extremely advantageous in industry. At higher temperature, the immobilized enzyme exhibits higher enzyme activity than that of the free enzyme.
TL;DR: In vitro studies here reported were performed to evaluate the inhibitory activity of five species (as hydroalcoholic extracts) of edible plants from Calabria region (Italy) on amylase and lipase by monitoring the hydrolysis of p-NPC and the hydroolysis of glycoside bonds in digestible carbohydrate foods.
Abstract: One of the most important strategy in the treatment of obesity includes the development of nutrient digestion and absorption inhibitors. Inhibition of digestive enzymes is one of the most widely studied mechanisms used to determine the potential efficacy of natural products as hypolipidemic and hypoglycaemic agents. In vitro studies here reported were performed to evaluate the inhibitory activity of five species (as hydroalcoholic extracts) of edible plants from Calabria region (Italy) on amylase and lipase by monitoring the hydrolysis of p-NPC and the hydrolysis of glycoside bonds in digestible carbohydrate foods. The formulation obtained from Clematis vitalba L. exhibited the strongest inhibitory effect on pancreatic lipase (IC50 = 0.99 mg/ml) and on α-amylase (IC50 = 31.52 μg/ml). In order to explore metabolome production HPTLC analysis of the extracts was performed, revealing the predominance of (±)-catechin, caffeic acid and chlorogenic acid in C. vitalba formulation at concentration of 23.18 ± 3.14, 13.63 ± 0.65 and 18.88 ± 0.76 mg/g, respectively. GC/MS analysis was used to identify fatty acids and terpene composition.
TL;DR: Gt-amy, a gene encoding acidic, thermostable and raw starch hydrolysing α-amylase was cloned from an extreme thermophile Geobacillus thermoleovorans and expressed and reveals that inhibition occurs as a result of binding to a lower affinity secondary Ca2+ binding site in the active centre in a mixed-type inhibition manner.
Abstract: A gene encoding acidic, thermostable and raw starch hydrolysing α-amylase was cloned from an extreme thermophile Geobacillus thermoleovorans and expressed. The ORF of 1650 bp encodes a 515 amino acid protein (Gt-amy) with a signal peptide of 34 amino acids at the N-terminus. Seven conserved sequences of GH-13 family have been found in its sequence. The specific enzyme activity of recombinant Gt-amy is 1723 U mg−1 protein with a molecular mass of 59 kDa. It is optimally active at pH 5.0 and 80 °C with t1/2 values of 283, 184 and 56 min at 70, 80 and 90 °C, respectively. The activation energy required for its temperature deactivation is 84.96 kJ mol−1. Ca2+ strongly inhibits Gt-amy at 10 mM concentration, and inhibition kinetics with Ca2+ reveals that inhibition occurs as a result of binding to a lower affinity secondary Ca2+ binding site in the active centre in a mixed-type inhibition manner. The Km and kcat of the Gt-amy are 0.315 mg mL−1 and 2.62 × 103 s−1, respectively. Gt-amy is Ca2+-independent at the concentration used in industrial starch saccharification, and hydrolyses raw corn and wheat starches efficiently, and thus, is applicable in starch saccharification at the industrial sub-gelatinization temperatures.
TL;DR: The ethanol extract of Cistus laurifolius is found to be a potent inhibitor of α-glucosidase and α-amylase, possibly due to several polyphenolic compounds present within the extract.
TL;DR: An extracellular haloalkaliphilic thermostable α-amylase producing archaeon was isolated from the saltwater Lake Urmia and identified as Halorubrum xinjiangense on the basis of morphological, biochemical, and molecular properties.
Abstract: An extracellular haloalkaliphilic thermostable α-amylase producing archaeon was isolated from the saltwater Lake Urmia and identified as Halorubrum xinjiangense on the basis of morphological, biochemical, and molecular properties. The enzyme was purified to an electrophoretically homogenous state by 80 % cold ethanol precipitation, followed by affinity chromatography. The concentrated pure amylase was eluted as a single peak on fast protein liquid chromatography. The molecular mass of the purified enzyme was about 60 kDa, with a pI value of 4.5. Maximum amylase activity was at 4 M NaCl or 4.5 M KCl, 70 °C, and pH 8.5. The K m and V max of the enzyme were determined as 3.8 mg ml(-1) and 12.4 U mg(-1), respectively. The pure amylase was stable in the presence of SDS, detergents, and organic solvents. In addition, the enzyme (20 U) hydrolyzed 69 % of the wheat starch after a 2-h incubation at 70 °C in an aqueous/hexadecane two-phase system.
Journal Article•
TL;DR: In this paper, the nutritional potential of an important underutilized fruit of pumpkin (Cucurbita maxima D) at its sequential stages of development was investigated, and the results revealed that pumpkin fruits on ripening accumulated considerable amount of carotenoids, vitamin C and proteins along with carbohydrates.
Abstract: Growing population, together with unpredictable climatic changes and dwindling fertile land, has forced to explore the alternate underutilized flora from the rich biome. There is a great opportunity for economic growth in agriculture system by introducing underutilized commodity in market place. Therefore, the present study was undertaken to elucidate the nutritional potential of an important underutilized fruit of pumpkin (Cucurbita maxima D.) at its sequential stages of development. Changes in various physico-biochemical properties such as pH, titratable acidity (TA), carbohydrates, free amino acids, total proteins, total phenols, carotenoids, ascorbic acid and the specific activities of softening enzymes (β-galactosidase, cellulase, pectin methylesterase and polygalacturonase), hydrolytic enzymes (amylase and invertase) and antioxidant enzymes (peroxidase, polyphenoloxidase, superoxide dismutase, catalase and ascorbic acid oxidase) were investigated. The results revealed that pumpkin fruits on ripening accumulated considerable amount of carotenoids, vitamin C and proteins along with carbohydrates. Due to enhanced activities of amylase and invertase during ripening of pumpkin fruit, starch degradation occurred concomitantly with the increasing pattern of reducing sugars and total sugars. β-galactosidase and cellulase enzymes actively involved in cell wall degradation than that of pectin methylesterase (PME) and polygalacturonase (PG), while the activities of antioxidant enzymes exhibited declining pattern towards its maturation and ripening. The physico-biochemical study of particular commodity would be useful to assist in the selection of fruit at appropriate stage of development and its utilization in acceptable manner.
TL;DR: The purpose of this review is to summarize for the first time the available data about the starch-modifying enzymes in ALAB and to discuss the possible application of ALAB strains for direct production of lactic acid from starch, as well as their participation in food manufacturing.
Abstract: In spite that lactic acid bacteria (LAB) are used for production of fermented foods and drinks for millennia, their ability to grow using starch as a sole carbon source was noticed by the scientists in the last 30 years. A number of amylolytic LAB (ALAB) strains were isolated and several detailed investigations of biochemical and genetic basis of starch hydrolysis were performed. The purpose of this review is to summarize for the first time the available data about the starch-modifying enzymes in ALAB. The most important amylolytic representatives of the genera Lactobacillus, Lactococcus, Streptococcus, Pediococcus, Carnobacterium, and Weissella are described. Amino acid sequences, corresponding to ALAB amylase enzymes are compared and some features of the gene expression are analyzed. The possible application of ALAB strains for direct production of lactic acid from starch, as well as their participation in food manufacturing is discussed.
TL;DR: It is indicated that white seabream has higher ability to digest non-protein energy sources than meagre and that diet supplementation with BSY improved digestive capacities in both species.
TL;DR: The single-step conversion of raw starch represents significant progress towards the realisation of CBP without the need for any heat pretreatment and furthermore, the amylases were produced and secreted by the host strain, thus circumventing theneed for exogenous amylase.
Abstract: Starch is one of the most abundant organic polysaccharides available for the production of bio-ethanol as an alternative transport fuel. Cost-effective utilisation of starch requires consolidated bioprocessing (CBP) where a single microorganism can produce the enzymes required for hydrolysis of starch, and also convert the glucose monomers to ethanol. The Aspergillus tubingensis T8.4 α-amylase (amyA) and glucoamylase (glaA) genes were cloned and expressed in the laboratory strain Saccharomyces cerevisiae Y294 and the semi-industrial strain, S. cerevisiae Mnuα1. The recombinant AmyA and GlaA displayed protein sizes of 110–150 kDa and 90 kDa, respectively, suggesting significant glycosylation in S. cerevisiae. The Mnuα1[AmyA-GlaA] and Y294[AmyA-GlaA] strains were able to utilise 20 g l-1 raw corn starch as sole carbohydrate source, with ethanol titers of 9.03 and 6.67 g l-1 (0.038 and 0.028 g l-1 h-1), respectively, after 10 days. With a substrate load of 200 g l-1 raw corn starch, Mnuα1[AmyA-GlaA] yielded 70.07 g l-1 ethanol (0.58 g l-1 h-1) after 120 h of fermentation, whereas Y294[AmyA-GlaA] was less efficient at 43.33 g l-1 ethanol (0.36 g l-1 h-1). In a semi-industrial amylolytic S. cerevisiae strain expressing the A. tubingensis α-amylase and glucoamylase genes, 200 g l-1 raw starch was completely hydrolysed (saccharified) in 120 hours with 74% converted to released sugars plus fermentation products and the remainder presumably to biomass. The single-step conversion of raw starch represents significant progress towards the realisation of CBP without the need for any heat pretreatment. Furthermore, the amylases were produced and secreted by the host strain, thus circumventing the need for exogenous amylases.
TL;DR: The production of α-amylase is essential for conversion of starches into oligosaccharides, and the properties of each α-Amylase such as thermostability, pH profile, pH stability, and Ca-independency are important in the development of fermentation process.
Abstract: Amylases are widely distributed and are one of the most studied enzymes. Such enzymes hydrolyze the starch molecules into polymers composed of glucose units. Amylases have potential application in a wide number of industrial processes such as food, fermentation and pharmaceutical industries. Amylases can be obtained from plants, animals and microorganisms. However, enzymes from fungal and bacterial sources have dominated applications in industrial sectors. The microbial source of amylase is preferred to other sources because of its plasticity and vast availability. The production of α-amylase is essential for conversion of starches into oligosaccharides. Starch is an important constituent of the human diet and is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. The properties of each α-amylase such as thermostability, pH profile, pH stability, and Ca-independency are important in the development of fermentation process. This review focuses on the isolation, substrates of α-amylases, production of bacterial and fungal α-amylases, properties of α-amylases, and the use of these enzymes in industrial applications.
TL;DR: Beta-amylase glutaraldehyde derivative was the preparation with best features, presenting improved temperature and pH stability and activity, and the possibility of reusing the amylase was also shown, when this immobilized enzyme was fully active for five cycles of use.