enzyme catalysis
TRANSCRIPT
CHAPTER 4ENZYME CATALYSIS
ENZYME CATALYSIS
Application of Hydrolytic Enzymes. Enzyme Immobilization Technology:- Methods of enzyme immobilization.- Immobilized enzyme kinetics.
SUBCHAPTER
INTRODUCTION
OBJECTIVE OF THIS CHAPTER: To study some of the applications of enzymes. To examine immobilized enzyme catalyst formulations (allow sustained, continuous use of the enzyme).
Some enzymes of industrial importanceName Source Application Notes
Diastase MaltDigestive aid, supplement to bread, syrup
α-amylase activity, β-amylase activity
Takadiastase Aspergillus oryzae
Digestive aid; supplement to bread, syrup
Contains many other enzymes, protease, R-Nase
Amylase Bacillus subtilis
Desizing textiles, syrup, alcohol fermentation industry, glucose production
Crude preparation contains protease
Acid-resistant amylase
Aspergillus niger Digestive aid Optimum pH 4-5
Cont' ( starch-saccharifying amylase)Name Source Application
Amyloglucosidase
Rhizopus niveus, Aspergillus niger, Endomycopsis fibuliger
Glucose production
Cont' ( animal and vegetable protease)Name Source Application
Trypsin Animal pancreas Medical uses, meat tenderizers, beer haze removalPepsin Animal stomach Digestive aid, meat tenderizerα-Chymotrypsin Animal stomach medical uses
Rennet Calf stomach cheese manufacturePancreas protease Animal pancreas Digestive aid, cleaning, leatherbathing, dehairing, feed improvement
Papain Papaya digestive aid, medical uses, beer haze removal, meat tenderizerBromelain, ficin PIneapple, fig digestive aid, medical uses, beer haze removal, meat tenderizer
Cont' ( microbial protease)Name Source Application Notes
Protease
Aspergillus oryzae Flavoring of sake, haze removal in sake -
Aspergillus niger feed, digestive aidacid resistant protease, optimum pH
Bacillus subtilisdetergents, removal of gelatin from film (recovery of silver), fish solubles, meat tenderizer
optimum pH 7
Streptomyces griseus
detergents, removal of gelatin from film (recovery of silver), fish solubles, meat tenderizer
optimum pH 8
Varidase Streptococcus sp. medical use lederle
Streptokinase Streptococcus sp. medical use profibrinolysin
APPLICATION OF HYDROLYTIC ENZYMES
Hydrolytic Enzymes ???
An enzymes that catalyzes hydrolysis.
Protein Carbohydrate Fat molecules Polymers
Simplest Units
Hydrolysis Process
Hydrolytic Enzymes ???
Hydrolytic enzymes
Hydrolytic EnzymesEnzyme Substrate Hydrolysis productEsterases:Lipase Glycerides (fats) Glycerol + fatty acids
Phosphatases:LecithinasePectin esterase.LecithinPectin methyl ester
.Choline + H3PO4 + fatmethanol + polygalacturonic acidCarbohydrases:Fructosidaseα-glucosidase (maltase)β-glucosidase (cellobiase)β-galactosidase (lactase)AmylasesCellulaseCytasePolygalacturonase
.SucroseMaltoseCellobioseLactoseStarchCellulose.Polygalacturonic acid
.fructose + glucoseglucoseglucosegalactose + glucosemaltose or glucose + maltooligosaccharidescellobiosesimple sugarsgalacturonic acidNitrogen-carrying compounds:ProteinasesPolypeptidases proteinsproteins
polypeptidesamino acids
Desaminases:UreaseAsparaginaseDeaminaseureaasparagineamino acids
CO2 + NH3Aspartic acid + NH3NH3 + organic acids
Hydrolysis of Starch & Cellulose
Amylasescan hydrolyze the glucosidic bonds in starch and related glucose-containing compounds
Saccharifying enzyme?
Hydrolysis of Starch & Cellulose
α-amylase
β-amylase
Starch-liquefying enzyme
Industry UseGlucose & syrup
total or partially hydrolysis of corn starch to give a large quantity of sweeteners.
Brewing conversion of crushed grain starch to maltose
Breadmaking leavening: conversion of sufficient starch to fermentable saccharides needed for CO2 generation
Fruit juice hydrolysis of starch causing turbidity due to insolubility
Papermaking alpha-amylase action to liquefy starch coating to a desired viscosity for application to fibers
TextilesSizing: alpha-amylase activity to liquefy starchDesizing: alpha,beta-amylse action to remove size from woven material so that all threads will dye uniformly and fabric will have desired texture.
Candy production of candy of desired softness
Common applications of amylse preparations
Proteolytic enzymeSynthesized in an inactive form suitable either for STORAGE or for TRANSPORT from the site of synthesis to the desired site of activityHOW to activate the proteolytic
enzyme?From a precursorBy presence of a metal ion
OHRCOOHROHCOORR 2121
Esterase ApplicationsTo synthesize of various ester bonds to yield an acid and an alcohol.
Hydrolytic enzyme applications which are expanding (in development)Enzyme ProcessPenicillin acylase Production of semysynthetic penicillin core from nature penicillin GLactase Removal of lactose from whey, milkRibonuclease Production of 5'-nucleotides from RNADextranase Removal of tooth plaqueIsoamylase Production of maltose from starchKeratinase Modification of wool, hair, leatherTannase Removal of tannic acid from foods
ENZYME IMMOBILIZATION TECHNOLOGY Methods of
enzyme immobilization
Immobilized enzyme kinetics
Immobilized Enzymes?
Introduction
Enzyme Immobilization????
To restrict enzyme mobility in a fixed space.
Enzyme Immobilization????
Immbolized enzymes are ATTACHED
to an insoluble suppport medium or enclosed by the support medium which is also known as a CARRIER
In some cases, the enzymes molecules are cross-linked to each other so that their movement is restricted but their catalytic
activities are retained.
Needed for Immobilizaton
ECONOMICAL
CONVENIENCE
STABILITY
continuous use of bio-catalyst is possible
separation of bio-catalyst & product is much easier than conventional batch process
Immobilized enzymes typically have greater thermal
& operational stability than the soluble form of the
enzyme
Methods for Enzyme Immobilization
Methods for immobilization enzyme
Carrier-binding Method
The oldest immobilization method. Carriers (water insoluble) such as polysaccharide derivatives, synthetic polymers, and porous glass, etc.
Cross-linking Method
Based on the formation of chemical bonds, but water-insoluble carriers are not used in this method. Reagents such as glutaldehyde, bisdiazobenzidine, and hexamethylene diisocyanate, etc.
Entrapping Method
Based on confining enzymes in the lattice of a polymer matrix or enclosing enzymes in semipermeable membranes. A chemical polymerization reaction e.g. cllagen, gelatin, cellulose etc.
Preparation & Characteristics of immobilized
enzyme
Preparation & Characteristics of immobilized enzyme
Benefits of immobilizing and ENZYME
Multiple or repetitive use of a single batch of enzymes.
The ability to stop the reaction rapidly by removing the enzyme from the reaction solution (or vice versa).
Enzymes are usually stabilized by bounding. Product is not contaminated with the enzyme
(especially useful in the food and pharmaceutical industries).
Analytical purposes - long 1/2-life, predictable decay rates, elimination of reagent preparation, etc.
Immobilized Enzyme Kinetics