Nhap mon cong nghe sinh hoc

Công nghệ sinh học protein và enzyme.

Enzyme Name GE Organism Use (examples)
-acetolactate bacteria Removes bitter substances decarboxylase from beer
 -amylase bacteria Converts starch to simple sugar
Catalase fungi Reduces food deterioration
Chymosin bacteria or fungi Clots casein to make cheese
-glucanase bacteria Improves beer filtration
Glucose isomerase bacteria Converts glucose to fructose
Glucose oxidase fungi Reduces food deterioration
Lipase fungi Oil and fat modification
Maltogenic amylase bacteria Slows staling of breads
Pectinesterase fungi Improves fruit juice clarity
Protease bacteria Improves bread dough structure
xylanase (hemicellulase) bacteria or fungi Enhances rising of bread dough
Enzymes in Biotechnology
1. Washing powders that have enzymes are called biological washing powders. They act on certain stains such as blood, grass stains:proteases, oils, fats: lipases. They make the detergent more effective (gets stains out better) and more efficient (use less)
Use of lactase in producing lactose-free milk
* The disaccharide lactose is present in milk and milk products.
* 70% of adults can’t breakdown lactose and so it builds up in the intestine (only monosaccharides can be absorbed)
* The bacteria that live in the gut can switch to lactose as their energy source by “turning on” the gene for lactase (an example of control of gene expression called the lac operon model).
* When the bacteria use the lactose it produces hydrogen gas and the person has intestinal symptoms.
* It is therefore benificial to have lactose-free milk available.
Reaction
Substrate: Lactose
This is a hydrolysis reaction
© 2008 Paul Billiet ODWS
Source
Lactase enzyme (-galactosidase) is extracted from fungi such as Aspergillus oryzae
http://www.biologie.uni-regensburg.de/
© 2008 Paul Billiet ODWS
Fruit juice production
Pectinases increase the yield of juice from fruit and make it clearer. Pectin is a large polysaccharide found in the cell wall. The enzymes hydrolyze the pectins and enable the easy extraction of larger volumes of clear fruit juice. Pectinase is an enzyme that is extracted from a fungus (Aspergillus niger). This fungus grows naturally on fruits and uses this enzyme to soften cell walls enabling its hyphae to grow through them.
Enzyme Glucose Oxidase được lấy từ Aspergillus niger và Penicillium. Nó có chuyên tính cao trong xúc tác sự tạo thành gluconic acid từ β-D-glucose bởi qua 2 bước

Glucose oxydase
β-D-glucose +O2 D-glucono-1, 5-lactone +H2O2

Phản ứng tự phát
D-glucono-1, 5-lactone +H2O Gluconic acid
Catalase
2H2O2 2H2O + O2

Sự oxy hóa của β-D-glucose thành gluconic acid bởi enzyme glucose oxidase
Một số các enzyme dùng trong công nghệ sản xuất nước trái cây và bia rượu
Nonfood Protease Applications
Medicine
Pharmacology & drug manufacture
Laundry & dishwashing detergents (#1)
Hard surface cleaning formulations
Contact lens cleaning formulations
Waste treatment
Industrial applications
Fermentation (fuel EtOH, etc.)
Chondroitin & heparin production
Animal feed additives
Digestive supplements
Protease Applications in Food Processing
Proteases are also used in a wide range of foods & food processing applications.

Dairy: milk coagulation, flavor development

Baking: gluten development

Fish & seafood processing: fishmeal, enhanced oil recovery, aquaculture

Animal protein processing: improved digestibility, reduced allergenicity, improved flavor, meat tenderization

Plant protein processing: improved functionality & processing, generation of bio-active peptides.

Yeast hydrolysis: flavor compounds.

Production of Value-Added Food Ingredients
Basic rationale: Proteases are a powerful tool for modifying the properties of food proteins.

Improved digestibility
Improved solubility
Modified functional properties: emulsification, fat-binding, water-binding, foaming properties, gel strength, whipping properties, etc.
Improved flavor & palatability
Improved processing: viscosity reduction, improved drying, etc.
An Example: Soy Protein Modification
Soy Oil
Solvent Extraction
Defatted Soymeal
Aqueous Extraction
Isoelectric Precipitation
Soy Protein Isolate (90%)
CHO residue
“Whey”
Soy beans
The protein in the soy isolate has been subjected to several harsh denaturing processes. As a result it has very poor solubility and functionality compared to a “native” soy protein.
Glucose oxidase
glucose oxidase converts glucose to gluconic acid and hydrogen peroxide
when the reaction is performed in the presence of peroxidase and o-dianisidine a yellow color is formed
this forms the basis for the measurement of urinary and blood glucose
Testape, Clinistix, Diastix (urinary glucose)
Dextrostix (venous glucose)




Polygalaturonase Breaks down cell walls.
Pectin esterases
Pectin esterases are cell wall metabolizing enzymes responsible for the deesterification of methyl esters of galactosiduronic acid units in peptic compounds. The pectin esterase reaction yields substrates for:

Depolymerizing enzymes (polygalactouronases and pectate lyases). They are involved in modulation of cell wall features. They take part in pollen germination and in defense against pathogens. Pectin esterases are found in all species of higher plants examined and are also produced by phytopathogenic bacteria and fungi in multiple forms.
Hemicellulases

• Enzymes that break down hemicellulose and various side chains in hemicellulose to form xylose and other sugar monomers

• Hemicellulose hydrolysis requires synergistic action of many enzymes

• Hemicellulases can render cellulose more accessible to cellulases

• Commercial hemicellulase development is less advanced than cellulase development