Effects of additives on the growth.pdf

7/24/2019 Effects of additives on the growth.pdf

1/7

ELSEV IER

Journa l of Crysta l Growth 178 (1997/ 568-574

j C R Y S T A L

G R O W T H

E f f e c t s o f a d d i t i v e s o n t h e g r o w t h

o f L - g l u t a m i c a c i d c r y s t a ls p - f o rm )

C h i a k i S a n o a * , T a t s u k i K a s h i w a g i b, N o b u y a N a g a s h i m a b, T e t s u y a K a w a k i t a a

a Technology Engin eer ing Laboratories, Aj inom oto Company, Inc ., 1-1 Suzuki -cho. Kawasaki-ku . K awasa ki -shi 210, Japan

b Cen tral Res earc h Laboratories, Ajin om oto Com pany, Inc., 1- i Suzula'-eho, Kawasaki-ku, Ka wa saki -shi 210, Japan

Received 6 December 1996

Abstract

T o e l u c i d at e t h e m e c h a n i s m o f p o l y m o r p h - s e l e c t i v e c ry s t a l l iz a t i o n o f L - g l u t a m i c a c i d ( L - G l u ) c r y s ta l s b y t h e a d d i t iv e s ,

t h e e f f ec ts o f v a r i o u s L - a m i n o a c id s , c a r b o x y l i c a c id s , a n d a d i - p e p ti d e , y - L - g l u t a m y l - L - g l u t a m i c a c i d ( y - G l u - G l u ) o n t h e

g r o w t h o f t h e { 1 0 1 }, {0 1 0 } , a n d { 0 0 1 }, t h r e e d o m i n a n t f a c e s o f t h e B - f o r m o f L - G l u c r y s t a l s h a v e b e e n i n v e s t i g a t e d

e x p e r i m e n t a l l y a n d s t r u c t u r a l l y , y - G l u - G l u a n d L - p h e n y l a l a n i n e ( L - P h e ) s h o w e d n e a r l y t h e s a m e s t r o n g i n h i b i t o r y

e f fe c ts o n t h e t h r e e f a c es o f t h e 1 3- fo rm i n c o n t r a s t t o t h e i r d i f f e re n t b e h a v i o r o n t h e t w o d o m i n a n t f a c es o f t h e a - f o r m o f

L - G l u . T h e s e p h e n o m e n a w e r e e x p l a i n e d i n t e r m s o f t h e c h a r a c t e r is t i c s o f t h e h y d r o g e n b o n d s o f e a c h f ac e a n d i t w a s

f o u n d t h a t t h e B - f o rm h a s l e ss d i s c r i m i n a t i n g c a p a c i t y t h a n t h e a - f o r m f o r t h e r e c o g n i t i o n o f t h e m o l e c u l es . F i n a l ly , t h e

c a u s e o f t h e p o l y m o r p h - s e l e c t i v e c r y s t a ll i z a t io n b y t h e a d d i t i v e s i n t h e L - G l u i s a tt r i b u t e d m a i n l y t o t h e d i f f e re n c e i n t h e

i n h i b i t o r y e f f ec t s o f t h e a d d i t i v e s o n t h e t w o d o m i n a n t f a c es o f t h e a - f o r m .

P A C S : 61.50 .K; 61 .66.H q; 61 .72.Ss; 61 .72. - y ; 81 .10.Aj ; 81 .10 .Dn ; 84 .30.Y

K e y w o r d s : L - g l u t a m i c a c id ; P o l y m o r p h ; T r a n s f o r m a t i o n ; T a i l o r - m a d e a d d it iv e s; A m i n o a c i d

1 I n t ro duct i o n

L - g l u t a m i c a c i d ( L - G l u ) c r y s t a l s h a v e t w o p o l y -

m o r p h s : g r a n u l a r a - a n d p l a t e - l ik e [ 3- fo rm s [1 ] . T h e

c r y s t a l s t r u c t u r e s o f t h e tw o p o l y m o r p h s w e r e d e -

t e r m i n e d b y X - r a y [ - 1 -4 ] a n d n e u t r o n [ 5 , 6 ] d i f f ra c -

t i o n s . T h e a - f o r m ( s p a c e g r o u p P 2 2 22 2 2, a = 7 .0 6 8 ,

b = 1 0 .2 7 7, c - - 8 . 7 7 5 A E 4 ]) i s m e t a s t a b l e a n d

* Correspond ing auth or. Fax: + 81 44 211 7832.

t r a n s f o r m s t o t h e s t a b l e [ 3 - fo r m ( s p a c e g r o u p

P 21222 1 , a = 5 .159 , b = 17 .30 , c = 6 .948 A [ -6 ] )

m e d i a t e d b y w a t e r [ -7 , 8 ] . F r o m t h e v i e w p o i n t o f

i n d u s t r i a l c r y s t a l l iz a t i o n , t h e a - f o r m i s p r e f e r a b l e i n

s h a p e t o t h e [ 3 -f o rm b e c a u s e o f i ts m u c h b e t t e r

s e p a r a b i l i t y f r o m t h e m o t h e r l i q u o r [-4 ]. A d d i t i v e s

f o r t h e s e l ec t i v e c r y s t a l l i z a t i o n o f t h e s e p o l y m o r p h s

h a v e b e e n i n v e s t i g a t e d f o r t h e in d u s t r ia l p r o d u c -

t i o n o f m o n o s o d i u m L - g l u t a m a t e ( M S G ) . L - a -

a m i n o a c i d s, s u c h as L - p h e n y l a l a n i n e ( L - P h e ) h a v e

b e e n f o u n d e f f ec t iv e n o t o n l y i n c r y s t a l li z i n g t h e

0022-0248/97/ 17.00 Co pyr ight 1997 Elsevier Science B.V. All rights reserved

P I I 8 0 0 2 2 - 0 2 4 8 ( 9 7 ) 0 0 0 1 3 - 4


2/7

C. Sano et al. / Journal of C rystal Growth 178 1997) 568 -574 569

a - f o r m [ 9 ] b u t a l s o in in h i b i t i n g t h e tr a n s f o r m a t i o n

f r o m t h e a - f o r m t o t h e [ 3 -f o rm [- 10 ]. F u r t h e r , t h e

d i - p e p t i d e y - L - g l u t a m y l - L - g l u t a m i c a c i d (y - G l u -

G l u ) h a s b e e n r e p o r t e d t o b e t h e o n l y e f fe c ti v e

y - L - g l u t a m y l p e p t i d e a m o n g y - G l u - V a l , y - G l u -

L e u , a n d y - G l u - G l u - G l u f o r c r y s t a l l i z i n g t h e [ 3 -

f o r m [ 1 1 ] . T h e i n d u c t i o n o f o n e p o l y m o r p h b y

a d d i t i v e s is t h o u g h t t o b e c l o s e l y r e l a te d t o t h e

g r o w t h i n h i b i t i o n o f a n o t h e r p o l y m o r p h . T o e lu c i-

d a t e t h e m e c h a n i s m o f p o l y m o r p h - s e l e c ti v e c r y s-

t a l li z a t io n b y a d d i ti v e s , w e h a v e s e p a r a t e l y i n v e s t i-

g a t e d t h e e ff e ct s o f L - P h e , 7 - G l u - L e u , a n d 7 - G l u -

G l u o n t h e g r o w t h o f t w o d o m i n a n t f a ce s {1 1 1 }

a n d { 0 0 1 } o f t h e a - f o r m [ 1 2 ]. R e s u l ts s h o w e d t h a t

t h e { 1 1 1 } f a c e s o f th e a - f o r m w e r e s t r o n g l y i n h i b -

i te d b y L - P h e , y - G l u - L e u , a n d y - G l u - G l u , b u t t h e

{ 0 0 1} f a ce s w e r e i n h i b i t e d o n l y b y y - G l u - G l u

[ 1 2 ] . H o w e v e r , t h e e f f ec ts o f th e s e a d d i t i v e s o n t h e

[ 3 - f o r m h a v e n o t b e e n k n o w n . H e r e , t h e [ 3 - f o r m

c r y st a ls o f L - G l u h a v e b e e n g r o w n w i th a d d i ti v e s

h a v i n g p a r t i a l l y s i m i l a r c h e m i c a l s t r u c t u r e s t o

L - G l u ( i . e . , " t a i l o r m a d e a d d i t i v e s " [ 1 3 ] ) a n d

the i r e f f e c ts on the J3- fo rm c r ys t a l s h a v e

b e e n e x p e r i m e n t a l l y a n d s t r u c t u r a l l y i n v e s ti -

g a t e d .

2 Exp e r i m e n ta l p r oce d u re

2 .1 . Se e d c ry s ta l s and de t e rmina t ion o f t he i nd i ce s

o f t h e f a c e s

T h e s o l u b i l it y o f t h e [ 3- fo rm o f L - G l u w a s r e -

p o r t e d a s l o g S = - 0 . 4 61 + 0 . 0 1 5 9 x T , h e r e S i s

t h e s o l u b i l i t y ( g o f s o l u te p e r 1 0 0 g o f w a t e r ) a n d

T i s t e m p e r a t u r e ( C ) [1 4 ] . T h e 3 2 3 K s a t u r a t e d

L - G l u a q u e o u s s o l u t i o n w a s l e ft a t 3 0 0 K f o r o n e

d a y t o c r y s t a l l i z e [3 - fo r m s e e d c r y s t a l s , w h i c h w e r e

t h i n p l a t e - li k e s h a p e w i t h 1 .0 m m i n l e n g th , 0 .6 m m

i n w i d t h , a n d 0 .1 m m i n t h i c k n e s s a s s h o w n i n

Fig. 1 .

T h e r e l a t i o n b e t w e e n c r y s ta l s h a p e a n d c r y s ta l

a x i s w e r e d e t e r m i n e d w i t h X - r a y d i f f r a c t i o n t h a t

t h e , d i r e c ti o n o f t h e l e n g t h , t h e w i d t h , a n d t h e t h i c k -

n e s s w e r e r e l a t e d t o t h e a - , c - , a n d b - a x i s , r e s p e c -

t iv e ly . T h e i n d e x o f e a c h f a c e w a s d e t e r m i n e d b y

m e a s u r i n g t h e f a c e a n g l e s . T h e f a c e s a p p e a r e d a t

t h e e n d o f t h e a - a x i s w e r e i d e n t i f i e d a s { 1 0 1 }

c

~ a

1oi

/ ~ / 1 0 1 )

Fig. 1. Tlae morphology of the [3-form of L-glutamic acid

crystal.

a c c o r d i n g t o t h e f a c e a n g l e s o f 5 3 . 4 o r 1 2 6 .6 w i t h

t h e a -a x is 2 T h e { 0 1 0 } a n d { 0 0 } f a c e s d i d n o t

a l w a y s d e v e l o p w e l l .

2 .2 . T h e p r o c e d u r e o f c r y s ta l g r o w t h

A s e e d c r y s t a l w a s a t t a c h e d t o o n e e n d o f a t h i n

g l a ss f ib e r . T h e o t h e r e n d s o f t h e t w o f i b e r s w e r e

f i x e d t o t h e i n s i d e o f t h e c a p o f a g la s s t u b e , t h e n

t h e s e t w o s e e d c r y s t a ls w e r e d i p p e d i n t o 1 0 0 m l o f

L - G l u s u p e r s a t u r a t e d a q u e o u s s o l u t i o n w i t h o r

w i t h o u t a d d i t i v e s i n t h e t u b e . T h e s e c r y s t a l s w e r e

g r o w n f o r 1 5 h i n t h e g l a ss t u b e s i m m e r s e d i n

a s h a k i n g w a t e r b a t h c o n t r o l l e d a t 3 0 8 _+ 0 .1 K .

T h e s h a k i n g s p e e d a n d t h e a m p l i t u d e w e r e 3 0

s t r o k e s p e r m i n u t e a n d 4 c m , r e s p e c ti v e ly . T h e c o n -

c e n t r a t i o n o f L - G l u s o l u t i o n w a s 2 . 1 1 8 % ( w t/ w t) ;

w h i c h c o r r e s p o n d s t o t h e e q u i l i b r i u m c o n c e n t r a -

t i o n a t 3 2 3 K . T h e a d d i t i v e s w e r e a d d e d a t 1 o r

5 m o l % t o L - G l u . T h e p H o f t h e g ro w i n g s o l u t i o n

r a n g e d b e t w e e n 3 .0 a n d 3 . 4 w h e n v a r i o u s a d d i t i v e s

w e r e d i s s o l v e d . S i n c e t h e s a t u r a t e d c o n c e n t r a t i o n

o f L - G l u 1 3 -fo rm i s 1 . 2 3 1 % ( w t / w t ) a t 3 0 8 K [ 1 4 ] ,

t h e s t a r ti n g s u p e r s a t u r a t i o n o f t h e g r o w i n g s o l u -

t i o n w a s ~r = 0 . 72 1 . A f t e r 1 5 h t h e w e i g h t o f a

c r y s t a l i n c r e a s e d 0 .3 m g a t m o s t w h e n n o t h i n g

w a s a d d e d . T h e d e c r e a s e o f t h e s u p e r s a t u r a t i o n

d u r i n g t h e g r o w t h t e s t c a n b e e s t i m a t e d n e g l ig i b le .

T h e c r y s t a l s i z e s w e r e m e a s u r e d b y t a k i n g m i c r o -

p h o t o g r a p h s a f t e r o r i e n t a t i n g t h e c r y s t a l s e i t h e r

h o r i z o n t a l l y o r v e r t ic a l l y t o t h e c - a x is b e f o r e

a n d a f t e r t h e i n c u b a t i o n . S i x c r y s t a l s ( t h r e e t u b e s )

w e r e u s e d f o r e a c h g r o w t h e x p e r i m e n t , t h e r e s u l t s

w e r e a v e r a g e d , a n d s t a n d a r d d e v i a t i o n s w e r e c a l-

c u l a t e d .


3/7

570 C. Sano e t al . / J ou r na l o f Cr y s ta l Gr owth 178 1997) 56 8 - 57 4

2 3 Ma ter ials

F o l l o w i n g ad d i t i v e s h av e b een t e s t ed ; f o u r L -

amino ac ids (L-phenyla lan ine : L -Phe , L - lys ine : L -

Lys , L -aspar t i c ac id : L -Asp , an d L-a lan ine : L -Ala),

t w o D - am i n o ac i d s ( D - a l an i n e : D - A l a , D - g l u t am i c

ac i d : D - G l u ) , o n e y - L - g l u t am y l p ep t i d e ( y - L -

g l u t am y l - L - g l u t am i c ac i d : y - G l u - G l u ) , an d t h r ee

carboxyl i c ac ids (L-pyr ro l idone carboxyl i c ac id :

L - P C A , a - k e t o - g l u t a r i c a c i d : ~ - K G A , y - am i n o

buty l i c ac id : y -ABA) . L- lys ine was added as L-

lys ine hydro chlor ide : L -LysHC 1. A l l the am ino

ac i d s w e r e m ed i ca l g r ad e p r ep a r ed b y A j i n o m o t o

C o m p an y I nc . D - am i n o ac i d s an d ca r b o x y l i c a c i d s

w e r e p u r c h a s e d f r o m A l d r ic h C h e m i c al C o m p a n y

Inc . By the am ino ac id ana lys i s, les s than 0 .07

( w t /w t ) o f L - A s p w as d e t ec t ed i n t h e L - G l u u s ed i n

th i s exper iment .

2 4 Am ino acid and carboxylie acid analyses

T h e m o t h e r l i q u o r w as w i p ed o f f w i t h a f i lt e r

p ap e r f r o m t h e s eed c ry s ta l s . T h r ee o r f o u r s eed

crys ta l s among s ix c rys ta l s were d i s so lved in the

d i s t il l ed wa ter an d f ed to the a na lyses o f incorp or -

a t ed ad d i t iv e s f o r e ach ex p e r i m en t a l co n d i t i o n . L -

am i n o ac id s , D - A l a , y - G l u - G l u , an d y - A B A w er e

an a l y zed b y L - 8 5 0 0 am i n o ac i d a n a l y z e r ( H i t ach i

L i m it e d) a n d L - P C A a n d ~ - K G A w e r e a n a l y ze d b y

E Y E L A C - 3 0 0 0 ca r b o x y l i c a c i d an a l y ze r ( T o k y o

R i k ak i k a i C o m p an y L i m i t ed) . T h u s , t h e co n t en t s o f

t h e ad d i t i v e s o cc l u d ed in t h e g r o w n p a r t o f t h e

c r y s ta l s w e r e ca l cu l a t ed b y d i v i d i n g th e co n cen t r a -

t ions o f the add i t ives by th e c rys ta l weigh t in -

creased dur ing the growth t es t .

3 . R e s u l t s a n d d i s c u s s i o n s

3 1 Ef fects o f addi t ives on the grow th of each

crys ta l face

T h e av e r ag e g r o w t h r a t e s an d t h e s t an d a r d d ev i -

a t ions ( in paren thes i s ) o f 12 cont ro l c rys ta l s were

89.1 (9.3) gm /h f or the {1 0 1} faces, 1.82 (0.21) gm /h

for the {0 1 0} faces, 3 .76 (0.64) gm /h for the {0 0 1}

faces , r espec t ive ly . Whi le y -L-g lu tamyl pep t ide , L -

am i n o ac i d s an d y - A B A s h o w ed i n h i b i t o r y e f fects

120

100

~- 10o

8

60

4 0

I too l addi t ion

[ ] { lo l} T

8 iiiiiii ............ z .......... ] .... V ......

i X

7 G luGlu L-Ph e L L ys L A la L A sp g - A B A

120

20

0

7 GluGlu L-P he

L L y s L A la L A sp

y - A B A

Fi g . 2 . The e ff ec ts o f va r i ous a dd i t i ve s on t h e g r ow t h o f ] 3 f or m

of L g l u t a m i c a c i d c r y s t a l s.

on the g row th of the [3 - form crys ta l s, ca rboxy l i c

ac i d s , L - P C A an d ~ - K G A , an d D - am i n o ac i d s d i d

no t sh ow any inh ib i to ry e ff ec t. The e f fec t s o f add ing

1 o r 5 t o o l o f y - G l u - G l u , L - P h e , L - L y s , L - A la ,

L - A s p , an d y - A B A a r e s h o w n i n F i g . 2. T h e ad d i -

t ives showed s t ronger inh ib i to ry e f f ec t s in the

{0 1 0} a nd {0 0 1} faces th an in t he {1 0 1} faces.

The degree o f inh ib i to ry e ff ec ts o f the ad d i t ives

w as i n t h e d ec r ea s in g o r d e r o f y - G l u - G l u > L -

P h e > L - L y s > L - A s p > L - A la , y -A B A a t 1 m o l

ad d i t io n . A t 5 m o l , t h e e f fec ts o f L - P h e an d L -

Asp increased s ign i f i can t ly . L -Lys espec ia l ly sup-

pres sed th e gro wth of the {0 1 0} f aces. L -P he

show ed s t rong inh ib i t ion in the th ree f aces and

especial ly in the {0 0 1} faces , y-Glu -Glu , L-As p did

n o t s h o w an y l a r g e an i s o t r o p y o n t h e g r o w t h i n h i -

bi t io n o f the ~-form.


4/7


5/7

572 C . S a n o e t al. / J o u r n a l o f C r y s t a l G r o w t h 1 7 8 1 9 9 7 ) 5 6 8 - 5 7 4

Ta b l e 1

Hy drog en bo nds (HB) of the [3- form crys ta l of L-G lu

M o d e o f H B

Atom s of the [3-form

pe r t i c ipa t e H B f o r m a t i on

Mol e c u l e s a c c e p t o r dona t e H B

A t o m s

Pos t i t i ons

1 a - c a r boxy l O 1 7 - c a r boxy l H ( O 4)

2 a - c a r boxy l 02 a - a m i no H ( N 1)

3 e~-carboxyl 0 2 a-am ino H(N2)

4 7 - c a r boxy l 03 a - a m i no H ( N 3)

5 7 - c a r boxy l H ( O 4) a - c a r boxy l O 1

6 a - a m i no H ( N 1 ) a - c a r boxy l O 2

7 a - a m i no H ( N 2) ~ - c a r boxy l 02

8 a - a m i no H ( N 3) 7 - c a r boxy l 03

( - X + 1 , Y - 1 / 2 , - Z + 3 / 2 )

( - X + 1 / 2 , - Y , Z - 1 / 2 )

x - 1, Y, z)

x - 1 / 2 , - r + 1 / 2 ,

- z + 3 / 2 )

- x + 1, Y + 1/2, - z + 3/2)

( - - X + l / 2 , - - Y , Z + I / 2 )

x + 1, Y, z)

( X + 1 /2 , - - Y + 1 / 2 , - Z + 2 )

o l o

Fig. 4 . The mo lecular packing of the [3-form of L-glutamic ac id

crys ta l v iewed dow n the a-axi s.

f a ce . A l s o , t h e s m a l l g r o w t h r a t e o f t h e { 0 0 1 } fa c e s

c a n b e e x p l a i n e d b y t h e s a m e r e a s o n m e n t i o n e d

a b o v e , b u t i n t h i s ca s e, a k i n k s i te h a s n o h y d r o g e n

b o n d t o t h e t e r r a c e. T h e p r e c i s e e n e r g y c a lc u l a t i o n

w i l l e l u c i d a t e t h e g r o w t h a n i s o t r o p y m o r e q u a n t i t -

a t i v e l y [ 1 7 ] .

3.3 .3 . The e ffec ts o f addi t ives on the fac es

o f f i f o r m cr ys ta l

T h e a d d i t i v e s w h i c h d i d n o t s h o w a n y g r o w t h

i n h i b i t i o n n o r d e t e c t e d o n t h e f i - fo r m c ry s t a l w e r e

D - a m i n o a c i d s , a - K G A a n d L - P C A . T h e s t e r i c a l

h i n d r a n c e s b r o u g h t a b o u t b y t h e i r s p e ci fi c m o l e c u -

l a r s t r u c t u r e s a r e t h e c a u s e o f t h e i r e f fe c ts ; t h e

D - a - N H ~ - g r o u p o f D - a m i n o a ci ds , t h e s y n - p l a n a r

s t r u c tu r e c o n s is ts o f a - C O a n d a - C O O H g r o u p s

f o r a - K G A , a n d t h e p y r r o l id o n e r i n g f o r L - P C A

h i n d e r e d t h e s e m o l e c u l e s t o b e a d s o r b e d t o t h e

[3- form crysta ls .

T h e a d d i t i v e s w h i c h i n d i c a t e d i n h i b i t o r y e f f e c t s

a r e c l a s s i f i e d i n t o f o u r g r o u p s b y t h e i r m o d e s o f

h y d r o g e n b o n d f o r m a t i o n a s s h o w n i n T a b l e 2 . A l l

t h e m o l e c u le s h a v i n g t h e m o i e t y o f L - a - a m i n o a c id

c a n f o r m h y d r o g e n b o n d s t o t h e t h r e e d o m i n a n t

f a c e s o f t h e [3 -fo rm . T h i s c h a r a c t e r i s t i c o f h y d r o g e n

b o n d f o r m a t i o n o f th e [3 -fo rm e x p l a i n s i ts l o w e r

c a p a c i t y o f m o l e c u l a r r e c o g n i t i o n t h a n t h e a - f o r m .

T h e s i m il a ri ty in t h e h y d r o g e n b o n d f o r m a t i o n o f

a d d i t i v e s t o L - G l u i s i n t h e d e c r e a s i n g o r d e r o f

L - A s p > 7 - G l u - G l u > L - P h e , L - L y s , L - A l a > 7 -

A B A . T h i s o r d e r p o s i ti v e ly c o r r e s p o n d e d t o t h e

o r d e r o f d i s t r i b u t i o n f a c t o r s o f th e a d d i ti v e s. T h e

s t r e n g t h o f t h e i n h i b i t i o n d e p e n d s o n t h e m u l t ip l i -

c a t i o n o f t h e t w o f a c t o r s : 1 ) t h e s t a b i l i t y o n t h e

c r y s t a l f a ce , i.e ., t h e s i m i l a r i t y i n t h e h y d r o g e n b o n d


6/7

C. Sano et al. / Journal o f Crystal Growth 178 (1997) 568-574 57

o

o~

c~

u~

09

?

o

o

e.

cq

Effects of additives on the growth.pdf

Documents