Cellulases are o- glycosyl hydrolases (GHs) that hydrolyse β-1,4 glucosidic bonds in cellulose. Cellulase system is grouped into “glycoside hydrolases (GH) family” classified by different means, according to their substrate specifities, reaction, mechanisms or structural similarities. The cellulase complex is found to contain three basic components which may be present either as single polypeptide or can be grouped together into multienzyme complex known as cellulosome. Cellulase system is composed of three main classes based on their activity toward a wide range of substrates. This is rather difficult, since the enzymes have overlapping specificities toward substrates which themselves are poorly defined. The three main classes are:
a) Endoglucanases (endo-1, 4- β- glucanases or 1, 4- β-D-glucan 4-glucanohydrolases EC 3.2.1.4) hydrolyze cellulose chains at random positions in less crystal regions, to generate principally short chain oligosaccharides producing free ends with a rapid change in degree of polymerization. The substrates are amorphous cellulose, such as carboxymethylcellulose, H3PO4 or alkali-swollen cellulose, instead of crystalline cellulose.
b) Exoglucanases or cellobiohydrolases (exo-1, 4- β- glucanases or 1, 4- β-D glucan cellobiohydrolases EC 3.2.1.19) produce cellobiose by attacking free chain ends. They are thought to work processively, that is, one enzyme molecule can release several cellobiose units from the cellulose chain without leaving the substrate.
c) β- glucosidases or cellobiases (β- D glucoside glucohydrolases, EC 3.2.1.21)are very important components of the cellulase system in that they complete the hydrolysis to glucose of short-chain oligosaccharides and cellobiose which are released by the ot...
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...id, acetic acid, formic acid, H₂ and CO₂ as fermentation products which increases ecological, industrial and basic bioenergetics interests in this particularly thermophilic bacterial specie.
Thermophiles produce number of enzymes e.g. cellulases, xylanases, mannases etc which have many applications in various industrial processes including food, detergents, textile, paper, tanneries and biorefining sectors. However, usage of cellulases in industries faces a major setback due to high production cost and low enzymatic activity. This has encouraged investigation of novel cellulase from thermophiles with minimum cost and improved activity.
With the aim of prospecting for new cellulolytic enzymes more suitable for industrial needs, we described here the cloning and high level expression of the novel β-glucosidase BglB, of Clostridium thermocellum in Escherichia coli.
Glycoside Hydrolases are classified into 108 families according with the amino acid sequence similarities. One of these families is GH1 (Glycoside Hydrolases 1), this family consists of enzymes with various substrate specificities, and the enzymes are present is bacteria, Archaea and Eukaryota. The 3D structure of 18 of these enzymes had been determined, and although the extent of sequence varies between 17% and 45%, all the enzymes have a common (β/α)8-barrel motif, and two catalytic glutamate residues located at the C-terminal end of β-strands 4 and 7, which may give a clue about the mechanism of these enzymes.
1. If gas bubbles form then fermentation occurred. Glucose. Carbon dioxide. The enzyme didn’t recognize the structure of glactose, because of the orientation of the H and OH on the carbon 4 is different than glucose. The enzyme only identifies very specific substances.
Gut microbiota plays an important role in human metabolism. The important sources of energy for human and microbial cells are carbohydrates. Most complex carbohydrates and plant polysaccharides, such as cellulose, xylans, resistance starch and inulin cannot be digested by the human enzymes. The gut micro...
During the Organic Molecules experiment, four reagents were used to test for the presence of three of the four basic categories of Organic Molecules, carbohydrates, lips, and proteins, in control substances and Cheerios. For carbohydrates, I was testing, specifically, for the presence of reducing (polysaccharides) and non-reducing sugars (monosaccharides). Carbohydrates, both reducing and non-reducing, are important to the cell because they act as an energy source and are an important factor in building and the structure of important sugars like Ribose. Monosaccharides are important, specifically, because they are sources of nutrients to cells. An example of this would be glucose. (Campbell, 2014, 68) Non-reducing sugars, such as starch, serve as storage for cells and are hydrolyzed and broken down when sugars are needed for the cell. Some polysaccharides, such as cellulose, are used for structural purposes in cells. In plants, cellulose is
Despite of general properties of enzymes, the properties also varies from where it comes from and how it been produced. For instance, the enzymatic saccharification method in lignocellulosic bioethanol is generated by hydrolyzing cellulose and hemicelluloses. This method gets high attention because of its higher theoretical yield compared to other methods (Taneda et al., 2012). Acremonium cellulolyticus with high activities of cellulase, amylase and pectinase enzymes allow it for the easy separation of solids/liquids in potato pulp, resulting in high saccharification efficiency and a high recovery rate of products (Gao et al., 2014). On the other hand, Enzyme-modified carboxymethyl starch (ECMS) is beneficial in enhancing water holding capacity, emulsion stability and improving sensory characteristics of sausages with a declined fat content (Luo and Xu, 2011). Lipases and phospholipases of dormant cotton seeds have stability in heat, various media and nature of the hydrolysis of the lipids properties (Rakhi...
...Brighter appearance to coloured textiles thanks to a new cellulase from an extremophilic bacterium. Journal of Biotechnology 66, 231–233.
Ethanol can be made from many different plant sugars including starch and cellulose. Starch ethanol is the most common biofuel used in the world. It is made from kernels of corn, which is very easy to break down. This means that corn is very easily converted into ethanol. On the other hand, cellulose is not easily broken down into ethanol. Cellulose is found in the cell walls of plants, and resembles plant armor. The cellulose combines with lignin, which makes plants woody. During the process of making ethanol from cellulose, the lignin has to be separated from the cellulose because it is not fermentable. Figure 1 shows the complications of making cellulosic ethanol vs. other biofuels. The question marks indicate where the technology hasn’t
Abstract: Enzymes are catalysts therefore we can state that they work to start a reaction or speed it up. The chemical transformed due to the enzyme (catalase) is known as the substrate. In this lab the chemical used was hydrogen peroxide because it can be broken down by catalase. The substrate in this lab would be hydrogen peroxide and the enzymes used will be catalase which is found in both potatoes and liver. This substrate will fill the active sites on the enzyme and the reaction will vary based on the concentration of both and the different factors in the experiment. Students placed either liver or potatoes in test tubes with the substrate and observed them at different temperatures as well as with different concentrations of the substrate. Upon reviewing observations, it can be concluded that liver contains the greater amount of catalase as its rates of reaction were greater than that of the potato.
Lactulose is a synthetic disaccharide which is composed of one molecule of galactose and one molecule of fructose linked by a β1→4 glycosidic bond (2). Because lactulose is not naturally occurring, lactose, which consists of glucose and galactose, is often used as the precursor molecule for lactulose production. In order to produce lactulose from lactose, isomerization of lactose must occur in which the galactose subunit is removed from lactose and joined to a molecule of fructose. Isomerization of lactose can be accomplished using chemical or enzymatic methods. Chemical methods employ an alkaline catalyst, such as sodium hydroxide or potassium hydroxide, in combination with a complexing agent, such as borate or aluminate, that will attach to lactulose and precipitate as an insoluble complex from the reaction system, thus shifting chemical equilibrium in favor of the formation of the lactulose product; lactulose synthesis by this method can result in up to 80% yield of lactulose. Enzymatic methods accomplish isomerization of lactose via transgalactosylation using β-galactosidases, which hydrolyze the β1→4 glycosidic bond of lactose. In the presence of fructose, the galactose subunit of lactose is ideally added to the hydroxyl group of the four prime carbon of fructose to form lactulose. However, the addition of galactose to fructose is not restricted to the four prime carbon because fructose contains other hydroxyl groups on multiple carbon atoms; therefore, enzymatic isomerization of lactose can yield various constitutional isomers of lactulose containing β1→1 or β1→6 glycosidic bonds (3).
By taking a Carbon Dioxide, rich substance and mixing it with a yeast, solution fermentation will occur, and then it could be determined if it is a good energy-producer. In this study glacatose, sucrose, glycine, glucose, and water were used to indicate how fast fermentation occurred. The overall result shows that monosaccharides in particular galactose and glucose were the best energy source for a cell.
...on pathways/kinetics of soluble carbohydrate and proteins when used as a sole electron donor or in mixture i.e., 100% carbohydrate, 100% protein, 50%:50% carbohydrate:protein,75%:25% carbohydrate:protein, and 25%:75% carbohydrate:protein. In order to achieve the objective, I will use different advanced analytical tools, such as (i) microbial ecology tool (such as pyrosequencing, quantitative polymerase chain reaction, and clone library), (ii) electrochemical analyses tools (such as cyclic voltammetry, linear sweep voltammetry, electrochemical impedance spectroscopy, and chronoamperometry), and (iii) chemical analyses tools (such as high-performance liquid chromatography, gas chromatography, ion chromatography, and chemical oxygen demand measurements) to predict the pathways of organic wastes fermentation as well as studying the hydrolysis and fermentation kinetics
After 30 minutes, another 5 ml of acetic acid was added, followed by 1.5 g of NaClO2the following 30 minutes. These steps were repeated until a total of 6 g of NaClO2 was added. The mixture was heated for a further 30 minutes after the final sodium chlorite addition. The suspension was then cooled in an ice bath before being filtered using sintered glass crucible and rinsed with cold distilled water. A final wash was carried out using acetone. The crucible with holocellulose was air dried in an air-conditioned room until constant weight was achieved for further alpha-cellulose analysis. For hemicellulose determination, the oven-dry weight of cellulose was used for
Pectin is a complicated branched structure of acidic structural polysaccharides, established in fruits and bast fibers. Most of the structure consists of homopolymeric partially methylated poly-α-(1-4)-D-galacturonic acid residues, but there are substantial 'hairy' non-gelling areas of alternating α-(1-2)-L-rhamnosyl-α-(1-4)-Dgalacturonosyl sections containing branch-points with mostly neutral side chains (1-20 residues) of mainly L-arabinose and D-galactose (rhamnogalacturonan-I). Pectin is the most hydrophilic compound in plant fibres due to the carboxylic acid groups and is easily degraded by defibration with fungi [27]. Pectin along with lignin and hemicelluloses present in natural fibres can be hydrolysed at elevated temperatures.
During my undergraduate research project, I had the opportunity to work under the supervision of Prof. Dr. Mozammel Hoq, My research project focused on the production of cellulase by Trichoderma spp. using submerged fermentation technique at a renowned institution ,Bangladesh Council for Scientific and Industrial Research (BCSIR). Cellulase enzyme has practical application in textile industries. This research experience intensified my interest for pursuing higher education in related fields . After my successful undergraduate research work, I became fascinated by the power of microbes, and the fact t...
Some of the characteristics of Nata de coco are chewy, translucent, jelly-like and it is an indigenous dessert. On top of that, Nata de coco is most commonly sweetened as a candy or dessert, and can accompany many things including pickles, drinks, ice cream, puddings and fruit mixes. It is produced by the bacterial fermentation of coconut water. Nata de coco is produced by the fermentation of coconut water or coconut milk, which gels through the production of microbial cellulose by Acetobacter xylinus. Acetobacter xylinum is the most efficient and widely used cellulose-producing bacterium in fermenting the coconut water to produce the nata de coco. Chemical purities are one of the most important features of microbial cellulose, which distinguishes it from that of plants and is usually associated with hemicelluloses and lignin. Interesting properties of microbial cellulose allow nata de coco to con...