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Enzymatic modification of natural an...

Chakraborty, Soma.

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Enzymatic modification of natural and synthetic polymers using lipases and proteases.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Enzymatic modification of natural and synthetic polymers using lipases and proteases./
Author:	Chakraborty, Soma.
Description:	109 p.
Notes:	Source: Dissertation Abstracts International, Volume: 64-09, Section: B, page: 4560.
Contained By:	Dissertation Abstracts International64-09B.
Subject:	Engineering, Materials Science. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3104063

Enzymatic modification of natural and synthetic polymers using lipases and proteases.
Chakraborty, Soma.

Enzymatic modification of natural and synthetic polymers using lipases and proteases. - 109 p.

Source: Dissertation Abstracts International, Volume: 64-09, Section: B, page: 4560.

Thesis (Ph.D.)--Polytechnic University, 2004.

Enzymatic modification of natural/synthetic polymers [starch nanoparticles, poly (n-alkyl acrylates) and poly(vinyl formamide)] was studied. Enzymes used for catalysis were lipases and proteases.Subjects--Topical Terms:

1017759
Engineering, Materials Science.

Enzymatic modification of natural and synthetic polymers using lipases and proteases.
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035 $a (UnM)AAI3104063
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040 $a UnM $c UnM
100 1 $a Chakraborty, Soma. $3 1945416
245 1 0 $a Enzymatic modification of natural and synthetic polymers using lipases and proteases.
300 $a 109 p.
500 $a Source: Dissertation Abstracts International, Volume: 64-09, Section: B, page: 4560.
500 $a Adviser: Richard A. Gross.
502 $a Thesis (Ph.D.)--Polytechnic University, 2004.
520 $a Enzymatic modification of natural/synthetic polymers [starch nanoparticles, poly (n-alkyl acrylates) and poly(vinyl formamide)] was studied. Enzymes used for catalysis were lipases and proteases.
520 $a Starch nanoparticles (40nm diameter) were incorporated into AOT-coated reverse micelles. Reactions performed with the acylating agents vinyl stearate, ϵ-caprolactone and maleic anhydride in toluene in presence of Novozyme-435 at 40°C for 36h gave products with degrees of substitution of 0.8, 0.6 and 0.4 respectively. DEPT-135 NMR spectra revealed that the modification occurred regioselectively at the C-6 position of the glucose units. Infrared microspectroscopy showed that the surfactant coated starch nanoparticles diffuse into pores of Novozyme-435 beads, coming in close proximity with CALB to promote modification. The modified products retained nanoscale dimensions.
520 $a Catalysis of amide bond formation between a low molar mass amine and ester side groups of poly(n-alkyl acrylates)[poly(ethyl acrylate), poly(methyl acrylate) and poly(butyl acrylate)] was also examined. The nucleophiles were mono and diamines. Among the poly(n-alkyl acrylates) and the lipases studied, poly(ethyl acrylate) was the preferred substrate and Novozyme-435 the most active lipase. Poly(ethyl acrylate) in 80% by-volume toluene was reacted with 1 equivalent per repeat unit of hexyl amine at 70°C in presence of Novozyme-435. The product contained 10.6 mol% amide groups. Attempts to increase the amidation beyond 10–11 mol% by increasing the reaction time or use of fresh enzyme were unsuccessful, showing that poly(ethylacrylate-co-10mol%hexylacrylamide) is a poor substrate for further acylation. When chiral amines ([R,S]-α-methyl benzylamine, [R,S]-β-methyl phenyl amine) were used as nucleophiles, Novozyme-435 enantioselectively catalyzed amidation of poly(ethyl acrylate).
520 $a Poly(vinyl formamide), P(VfAm) by acid or base-catalyzed hydrolysis leads to poly(vinylamine), P(VAm), and corresponding copolymers. As an alternative to chemical hydrolysis a mild and selective enzymatic method was discovered. Fifteen proteases were evaluated for this transformation. Of these, PROT 7 was the most active. Within 24h PROT 7 gave products with 44% hydrolysis. Further hydrolysis was not observed by extending the reaction time because poly(vinylformamide-co-40%vinylamine) is a poor substrate for further hydrolysis. The sequence distribution of copolymers formed by chemical hydrolysis and enzymatic hydrolysis was compared. Chemical hydrolysis gave random copolymer. In contrast, PROT 7 gave block-like arrangement of VAm units.
590 $a School code: 0179.
650 4 $a Engineering, Materials Science. $3 1017759
650 4 $a Chemistry, Polymer. $3 1018428
690 $a 0794
690 $a 0495
710 2 0 $a Polytechnic University. $3 1249856
773 0 $t Dissertation Abstracts International $g 64-09B.
790 1 0 $a Gross, Richard A., $e advisor
790 $a 0179
791 $a Ph.D.
792 $a 2004
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3104063