H ^ T N G H I K H O A H O C C(bNG NGH6 SINH HOC T O A N Q U 6 C 2013
--r6ro'a'MOrs6-Biea-KieN^NDoixArcfliiiTOT7(T:;roBffl;7iOT
DELBRUECKII SSP DELBRUECKinHU NHAN LACTASE THEO PHUONG PHAP QUI HOACH THl/C NGHIEM
Quach Ddc Tfnh, VQ Thj TrOc Phirong, Le Hoa Nhir, Nguyen ThOy Htpong Tn/c^g 09/ iigc Bich Khoa, Bai hgc Quoc gia Tp. Ho Chi Minh
T6M TAT
Enzyme lactase c6 nhieu iing dvmg quan t t g i ^ Irong cong n ^ e p thm; p h i m . Bs t^o liSn dS cho thu nhan enzyme a quy m6 loo hon, chfing tfii chpn Lactobacillus delbrueckii ss^ delbrueckii tii bp giSng plian l | p H nguon sinh tSng hpp enzyme lactase. Trong nghien ciiu nAy, chfing toi lien h b i h toi mi mpt so dieu kien nuoi cay theo phuong phap qui hoach th^c nghiSm rih3m Ihu n h ^ lupng enzyme lactase cao nhat. Qua nghiSn cihi cho thay nguon carbon ihich hpp cho quS trinh sinh lactase ciia chiing Lactoimcillus delbruecldi ssp delbrueckii l i glucose. Theo phuong phSp b ^ m|il (RSM) - phmmg an clu triio c6 tflm (CCD) da thuc hiSn, cho thiy gii tej l6i u u cua ba yeu to cua diSu kien nu6i cay: N h i | t 3$ nuoi cSy {34,6° C), pR (6,25) vjk ty 1? cSy gi6ng (16%) .cho san lupng lactase c ^ d^i theo mo hlnh ia 64829 U/g. T h u ngbiSm nu6i c§y voi di€u b f n ciia mo hlnh, hoat tlnh lactase thu dupc sau hai ISn k i ^ tra d^l k h o ^ g 95% so voi kit qua thu dupc tii mo hinh,
Ji> khoa- LACtase, Lactobacillus delbrueckii ssp delbruecldi, probiotic
MdDAU
Enzyme p-galactosidase (P^-galadoside galaclohydrolase, EC 3.2.1.23), thirdng duvc gpi Ii lactase c6 kha n5ng thiliy phdn lactose Ih^nh hai den vj cSu thinh n&n nd la glucose v i galactose (Siham ef al., 2010). Lactase cd nhiSu i>ng dgng quan trgng Irong nginh cong nghiep thi^c ph^m. Si> dyng lactase gfip phln ISm giam hi|n tugng Wk tinh-lactose trong sO'a. Sin phlm-thuy phSn lactose nhb enzyme lactase gfip phin lim gISm vin 6e khfing dung n^p lactose, mfit vln de ' mSc phiii bWn mfii ni>a dan sfi trdn thi gifi'i.
Lactase co Ihe duvc Ihu nh^n tir nhieu nguSn vi sinh v|l khic nhau nhif vl khuan, nam men va nam moc. VI khuSn lactic dirg'C chi>ng minh l i cfi Snh hu-firig l6l bin si>c khoe con ngufi'i vi dugc sir dgng r$ng rii ti-ong cic sSn phSm thi/c phim ISn men. BSn cgnh do, vi khuan lactic cung l i thanh phan cOa nhfim vi khuin dyfl'ng rufit (Mlichovi Z et al., 2006).
Trong nghiSn cilu niy, chOng loi chgn chiJng vi khuin Lactobacillus delbrueckii ssp delbnieckii lam fifii tuong cung cSp enzyme lactase. Be giam chi phf san xuit enzyme Ihl vi§c lyc chgn as chat re ll^n v i san cfi cOng vfi'i vl sinh v|t san xull phO hgp. l6i iru hoa cac dilu ki§n nuoi cay l i rat can thiet. T6i iru hfia qui trinh ISn men de xiy di/ng mo hlnh nhim Ihu duo'c san iugng Ibn v i gia lang quy mfi san xuit cfi mfit 'f nghTa quan trgng trong vifc u-ng dyng nh&ng nghien cilu co bin lactase vio trong cong nghi#p. Chung Ifii si> dung phucrng phip RSM-CCD de toi uu hfia gi^ trj cac
yeu 15 dang dug'c nghiin ciiu.^ , . . - - •
NGUYEN L1?U vk PHlfaNG PHAP Nguyin liiu
ChOng vi dnh v$t. ChOng vi khuin Lactobacillus delbrueckii ssp delbrueckii 6ugc cung cap bdi bfi mfin Cong ngh# Sinh hgc, Trubng B§i hgc Bach Khoa, B^l hgc Quae gia Tp H6 Chl Minh.
M6i trubng nuoi c&y: _ ^ . . , . , , . . . - , .-^- . -"- - -^---=---- - - - - MT01 - Moi Iru&ngMRS Ifing: dung de nhin gi6ng, nuoi cay, khio sSt vi khuan L delbnieckii ssp delbrueddl.
. MT02 - Mfii Inrcrng MRS agar: dung de giu gifing, xic dinh m|t dfi"vi khuan L. delbrueckii ssp delbnieckii.
MT03 - Moi Irufi'ng MRS long thay glucose 20 g/L bing nguon carbon tiiich hgrp (gom glucose 20 g/L, lactose 20g/L, sucrose 20 g/L, glucose 10 g/L v i lactose 10 g/L) cho qua trinh slnh.lfing hg'p enzyme lactase 10" ohiUng L. delbrueckii ssp delbnieckii: dCing trong cac thi nghi#m sang lgc khi nang sinh long hgp lactase cua cac chOng vi khuan lactic.
Hfia chit: ONPG (o-tli&ophenyl-iB-D-galactopyranoside) ciia Duchefe. Ha l^n '•
So trf thl nghiem
Khao sit nguin carbon thlch hgp cho qua trinh len men thu enzyme
•Nufil cay vi sinh v$t Irong mfli tnrfi'ng MTOl cfi nguon carbon thay dfii: glucose (20 g/L), lactose (20 g/L), sucnase {20 g/L). glucose (10 g/L) v i lactose (10 g/L) fir pH 6,8 vdi tyle cay giong "10%, tiln hinh 0 0 37° C.Tl^n hinh Ihu enzyme Ihfi va xic i^nh hogt tlnh lactase.
Cac ylu l6 Ihlch hg'p sg dugc cfi dinh cho cic khao sal lilp theo
Thiet ki thi nghidm tim yiu tS & tim vi phuvng phip RSM-CCD
Bk thill ke thl nghiem toi uu bing mfi hlnh CCD,.tru6'c lign lim thl nghidm b tam cOa 3 ylu t6 cin khio sal l i nhi#t do
•nufli cly, pH nuoi cly.va tJ I# cly giong ttieo Bing 1. - .
HQI NGH! KHOA HOC CONG NGHE SINH HOC T O A N Q U 6 C 2013
B S n g l . MO'C khao sat ciia n h i l t d g nuoi cay, p H v a l J I? cay gi6ngde tim ttii nghl&mt?itam T f l p c l y gifing
(%v/v) .^cmirc
MCrcl MLPC 2 Miic 3 Miic 4 Miic 5
Nhi^t dfi nudi d y
rc)
27 32 37 42 47
Sau khi cfi c i c d i l m b tam I h l l t ke Ihf nghiem Iheo CCD ciJa p h l n m i m StalGraphlcs Centurion, d i g n nhan phuo'ng i n la yeu to tCrng p h l n 2^'' va dug'c nghifin c i i u fii 5 m i i o (-2, - 1 , 0, + 1 , +2) (Bang 2), cfi' 15 i h l nghifim d u g c lien f i i n h . B i n g 2. G l i trj 3 yeu to diing trong RSM -
xi Nhi$ld5nuOiclyfC) xi pH
Xj TJ 1$ c l y gi6ng (% w/w) -CCD
-2 27 5,0 4
Hp so ma hoa va tg nhiSn lircmg iing -1 0 1 32 37 4 2 5,5 6,0 6,5 7 10 13 .
2 47 7,0 '16 - H i m Sap i i n g dug'c chgn la ho?t linh enzyme lactase (Y, U/g). Mfi hinh hfia dug'c b i l u d i l n b i n g p h u o n g trinh b^c 2 : Y = bo + b|Xi + b2X2 + b3)a + b i j x i x z + btaXtXa + b23X2X3 + b u x j ^ + bzzXa^ + basXa^
Trong dfi b l , b2, ba l i c i c h§ s f i bac 1; b u , b i 3 , b z 3 l i c a c h§ sfi t u o n g t i c cOatCfng cgp yeu t f i ; xi,X2, X3,XiX2, X1X3, X a X j I i cac b i l n d§c l | p . Tlnh loan, l | p phirong trinh h6i quy, chgn d i l m I6i u u . Ti> k l l qua phan b'ch, x i c djnh m i i c tfil u-u cQa c i c yeu l f i cho san l u v n g lactase d ^ l ct,FC d ^ i .
Danh gli mo blnh thyv nghidm: Len men t h i i nghiem mfl hlnh tfii u u va so s i n h v d i k i t qua d y doan cCia mfi h l n h . Phu'QTig phap
Phuong phip visinh
K h i o s i l c i c d i l u kien nufli c l y anh h u d n g d i n qua Irinh Ien men b i n g phuong p h i p toi u u d o n y l u t f i , cac k i t q u i cua thf nghigm t o r d c la t i l n d l cho I h l nghidm tilp Iheo, Tfii m j l o i n p h l n cac yeu to b i n g phuang p h i p RSM - C C D . Phuomg phip hba sinh
Phuang phip thu enzyme fho: Sinh khfii v i k h u i n , du'g'c thu nhgn bang each ly t i m (5000 vflng/phOt trong 10 p h d i d 4°C), sinh khfii dug'c r i i a 2 lan trong dung dich dem sodium phosphate 0.03 M (pH 6',8); sau 36 h u y l n phO hfia sinh khoi vao dem phosphate bang each voltex. H u y l n phO t l b i o dug'c giu trong n u d e d i se dem di p h i v 5 l i b i o b i n g phu'ong p h i p SCP d g n g sfing si§u am.. Ly t i m (5000 vfing/phijt, 10 phiil) de thu djch nfii. Djch noi chfnh la djch enzyme t h 5 va d u p c b i o quan l?nh (Siham e( al., 2010). - -
Phuvng phip xic djnh hoat tlnh lactase
Hogl tlnh lactase dug'c x i c djnh d y a trfin p h i n i i n g v d i c o c h l l ONPG, khi lactase thuy p h i n ONPG se tgo ra galactose va o-nitrophenol ( m i u v i n g ) . Hfin hgp phan i>ng gfim 0,03 mL dich nfii v i 0,5 mL C P N G 15 mM thyc hign phan i i n g trong 1,47 mL sodium phosphate 0,03 M (pH 6,8). U 10 phOt d 3 7 ° C, cho v i o 2 mL NaaCOa I M d l dO'ng phan i i n g . S a u do, do dfi h i p thu OD d 420 nm (Hsu ef al., 2005). Mgt d o n vj hogt tinh enzyme-lactase d u p c d j n h nghTa IS iugng O N P tgo I h i n h khi s i i dung mfit d e n vj enzyme phan Org trong 1 phOt cCia 1 g sinh khfii khfi d u d i d i l u ki§n khao s i t , Phuomg phip phan tich s6 llfu
c a c thf nghigm d u p c thyc hifin ba l l n , so l i f u d u o c p h i n tfch theo phuong phap p h u o n q sai ANOVA b l n q p h l n m i m SPSS V.19, Excel 2007.
K ^ T QUA V A THAO L U ^ N
Khio sit nguon carbon thlch hgp cho qui trinh len men thu enzyme lactase
Ngufin carbon d i l u hfia s u sinh long hgp p-galactosidase d cac chOng vi sinh v | t khac nhau. Vai tro ciJa nguon carbon tronq q u i trinh sinh long hgp p-galactosidase r i t khac nhau va tily thflc v i o tiing. chung vi sinh v i t (Hsu et al., 20O5).
Ngufin carbon I n h hudng d i n qua trinh sinh tfing hg'p lactase cCia chOng L delbnieckii ssp delbnieckii 6uac t h l h i f i n tnang Bang 3. K . v sang 3. Anh hu'O'ng cfla ngu^n carbon den s y sinh t r u * n g vk sinh long hffp lactase.
..„,,»„ f ^ ^ , t „ Khfli luvng sinh kh6i khS Ho?t tlnh lacfase pgguon oartaon (.,QJ, g,^^) (U/g) Glucose
Sucrose Lactose 'Glucose-Lactose
35 ± 0,7071 38 ±1,4142 36 ± 0,7071 32 ±1,0607
49673= ±4,31%
32935' + 5,54%
43073" ±4,16%
HO' NGI HKHQA-HOC cCiHiA NGHE SINH HQC T O A N Q U 6 C 2013
Vi srnh v$l ckn ngufin carbon d l lam b ^ ^ u o r i ^ j f i n g J i w ^ a c ^ h l U ^ ^ ^
—tfe/brHech/T-ssp-de/b/tren^ftfrthi-socrefsela nguon carbon toi u u cho s y smh tni'dng cCia no. Khoi l y p n g sinh khfii khe tiiii dupc khi mfii tardng chOg glucose chi b i n g 92% so von l u p n g sinh khfii khfl ttiu du'pc khi sCr dung sucrose (Bing 3) Glucose khflng la ngufin carton tfii u u cho s y sinh Irudng cua L. delbrueckii ssp delbnieckii nhung s y sinh tfing hwo lactase khi tt-ong mfii tnrfi'ng cfi chiia glucose I i cao n h l l (hogt linh lactase thu dugrc la 49673 U/g), l:iogt tinh l a c t ^ o t h i p n h l l thu dupc khi ngufln carbon la sucrose v i ch! bang 66,3% so v d i glucose. Tir do. glucose d u p c chgn la nguin carbon ttiich Hpp cho q u i f i n h sinh tfing h p p lactase cfla chflng L delbrueckii ssp delbnieckii. Theo khao sat cQa Nizamuddin va cpng s y (2008) glucose cung la ngufin carbon thlch h y p cho qua Irlnh sinh tfing hgp lactase cCia diflng Aspergillus oryzae (Nizamuddin et al.. 2008). K i t q u i nSy khfing phu h p p vfi'i k h i o s i l cua Hsu v i cgng s y (2005) tren dfii t u y n g BlUdobaderia. lactose l i ngubn carbon tfii m i cho s y sinh tfing hpp lactase va glucose khfing gicjp cho qua trinh long hpp lactase d i l n ra tfit hen (Hsu efa/., 2005). Khi bo sung lactose 10.g/L v i o m f i i - t r u d n g c f i chiia glucose 10 gA., hogt tinh lactase cfi xu hirdng giam xufing v i chi bang 86,7% so vfi'i hogt tfnh lactase khi sit dung glucose lam ngufin carbon. Ben cgnh dfl, H i i mfli b u d n g nufli cay cht c h i i a lactose, hogl tinh enzyme lactase' chi cfin 78,5% so vdi mfii tardng chiia glucose. T i i do cho ttily, lactose IS t i c nhSn kim ham q u i trinh sinh tfing hpp p-galactosidase cfla chung L delbnieckii ssp delbrueckii K i t qua khao sat cfla Kim va Rajagopal (2000) cung cho Ihay khi bfi sung lactose v i o mfli trudng cfi chiia galactose, ngufin carbon tfil u u cho q u i tt-lnh sinh tfing hpp lactase cfla chiJng L. crispatus, ttil hogl tfnh lactase cung gidm (Kim ef a/.,2000; Laxmi ef a/.,2011).
Nhu vgy, glucose dupc chgn l i ngufin carbon cho q u i trinh thu nh|in enzyme lactase cfla chflng L. delbrueckii ssp delbrueckii cho c i c khao s i t tilp Iheo. , "' -
Tnrbc khi t i l n h i n h c i c thf nghifim 161 u u , chflng tfii t i l n h i n h k h i o sat d u d n g cong smh Irudng v i d u d n g cong enzyme cfla chflng L delbrueckii ssp delbnieckii va x^c djnh d u p c thfi'i gian b u d c v i o pha c i n b i n g (ihu sinh khfii) cCta chflng la 16 g i d . Thdi gian nufii c l y v i Ihu nhgn enzyme lactase cfla L delbnieckii ssp delbnieckii cho cac thi nghifim toi u u l i 20 gid ifen men.
Kit qui thi nghidm b tim ciia mo. hinh CCD de t6i uv hba lugng lactase
Sau khi tfii y u tiing y l u l o rieng le bang phuong p h i p cfi dien d l l i m ttii nghi#m tgi l i m cfla mfi hinh CCD, t a i h u 6ugc ket qua n h u Bang 4. Cac d i l m tgi t i m la nhigt dfi nufli d y 37° C, pH 6,0 vS t j Ig c l y giong 10%. K i t qua k h i o s i l cfla Hsu v i cong s y (2005) cung ctio I h l y rang 37° C cung l i n h i f t dg tfil u u cho qua trinh sinh tfing h p p lactase cfla Bifidobacteria (Hsu ef a/., 2005). Theo c i c k h i o s i t cua Sriphannam v i cfing s y (2012) dfii v d i chung L. fermentum CM33 (Sriphannam ef al., 2012), Cristian v i cgng s y (2010) Iren dfii t u p n g Lactobacillus sp. LMI6, v i Hsu v i cfing s y (2005) Irgn Bifidobacteria pH 6,0 l i pH thfch hpp cho qua ttinh sinh tfing hpp lactase.
Bang 4. K i t qua khao sdt cac d l l m tai 13m cilia mfijilnh CCO
Host tfnh lactase (U/g) pH Tf I I gifing Ho?t Hnh lactase (% v/v) (U/g) Miic1
MO'C 5 27 32 37 42 . 47
30156''±3.8'!4 3 8 1 8 0 ' ± 1 . 5 % 49325° ± 2.8%
45295° ± 4 5%
7 8 8 5 ' ± 3 . 7 5 5.5
6 6 5 7
44367=^ ± 4 , 7 % 4 6 2 1 1 * ± 4 . 1 % 52925°+ 3.1%
4 9 6 5 7 " ± 4 . 1 % 45035" ± 3 . 5 %
35245" ± 5,4%"
3g778''±2.6%
50155° ± 4 . 7 % 43829= ± 3 . 5 % 4 0 7 3 4 " ± 5 . 1 %
Tfil u u hda g i i tr) c i c y l u t o i n h hufl'ng den s y s i n h l o n g h g p lactase bang p h u c n g p h ^ p RSM - CCD Sau khi tiln h i n h k h i o s5t theo k l hogch thyc nghigm (Bang 5), k i t q u i ttiu _ d u p c t h l h i e n trong Bang v d i ham d i p i i n g - d u p c lya chgn l i hogt Hnh lactase (¥).• " " """
Bang 5. Kha nang sinh tfing hgp lactase ciia L delbrueckii ssp cfe/brueck//tCf thuc-nghi?m to! uu c i c d i l u ki|n nuol c&y
Thi> ty thl nghi$m Blfin Hogt tinh lactase (U/g) 37
:w
2 4V 37?7 3?
37 47 47 37 37 37 37 37
6,0 6,5 b,U 6,5 6,0 6,0 S,5 5,5 5,5 5,9 5,0 7 0 6,0 6 0 6.0
4 13 10.
13 2 10 13 7 7 7 10 10 10 10 10
40224 51820 5362 ,53754 60927 36397 30922 37218 28884 15681 29094 36044
•58117 54795 45847
Sau khi phSn tfch phuong sai (ANOVA) phucmg trinh hoi quy d u p c dung n h u l i mfit njfl hinh d l tifin d o i n hogt Ifnh lactase thu d u p c . _,- '
HOI NGH! KHOA HQC C O N G NGH? SINH HOC T O A N QUC5C 2013
Bang 6: Miic dfi anh htrdng vS d ^ tin cay cua cac y l u tfi tfil u u flilu kien nufii c i y
Tfin y4u tfi MiJc dg anh hudng Bd tin c$y g a n g phan tfch (ANOVA) p h i n lich t i n g thanh p h l n rifing bigt v i U/ong t i c giO'a cdc y l u lfi. Sau do k i l m tta •j nghTa thfing ke cua h i n g y l u t f i . Trong tni'dng hpp n i y c6 4 y l u tfi (dupc in dgm) (Bang 6) cfi dfi tin c$y nhfi h a n 0,05 cho thay r i n g c f i s y sal khfic dang ke v d i m i i c d f i lin c | y ii 95%. Cic yeu t f i nao co p > 0,05 se b] logi ra khoi p h u c n g b'inh hfii quy.
P h u c n g trinh hfii quy cfi dgng:
Y = 5 2 9 1 9 , 7 - 5 8 8 3 , 6 x 1 + 5355,8X3 - 8010Xi^-5087.7X2^
K i t q u i phfin tich hfii quy cho ttily c i 3 y l u tfi nhifit dg nufii c l y , pH nufii c l y va t^ 1$ c l y gifing d l u Snh h u d n g d i n qua trinti sinh tfing h p p lactase cfla L. delbrueckii ssp delbnieckii. Nhi$t dg nufli d y d u p c x e m l i y l u tfi i n h h u d n g Idn n h i t , L delbnieckii ssp delbrueckii sinh tfing h p p lactase tfit h o n b nhifit 6b t h i p va khi n h l | t dfi t i n g cao Uii se t i c c h l q u i b'inh tfing hpp lactase. Khi pH mfli ttydng nufii c l y ban d l u tang ttil s y sinh tfing h p p lactase cfla chflng VI k h u i n n i y se giam. N g u p c Igi, ty Ig c l y gifing tang ttil hogt tfnh enzyme lactase ttiu d u p c se l i r i g . Mgt dap l i n g (Hlnh 1) t h l h i | n s y l u o n g t i c cfla iLFng c^P y l u tfi va t i i bieu dfi n i y cfi ttil xac dinh d u v c gia trj tfij^u cua tirng y l u ^ l i m cho ham d i p l i n g ^ c y c dgi. Hogt Ifnh lactase d u p c d y d o i n theo mfi hlnh dat n ' U/g khi nhigt dg nuBi c l y l i 34,6'*C, pH ban d l u 6,23 v i t J Ig c l y giong 16%.
8.16 5,18 6,76 21.79 0,12 2,66 8.79 0,01 0,12
0,0335 0.0720 0,0482 0,0055 0,7480 0,1636 0,0314 0,9362 0,7466
c toi da d 64829
Hlnh 1. M | l dap trng cila hoat tinh lactase theo n h i f t do vd pH Danh gia m f i h l n h t h y c n g h i f m
D l k i l m Ira k i t q u i cfla mfi hlnh, t i l n h i n h ttif nghifim v d i c i c g i i h i d y doan d l thu lactase eye dgi. Hoat Unh lactase nhan d u p c Kr k i t qua^ ttiyc nghigm l i 61467 v i 60892 U/g, k l l qua n i y dgt khoang 95% so vdi hogt Hnh lactase thu flupc theo d y d o i n d i a mfi hlnh l i 64829 U/g. S y t u a n g quan chfit che giua hai k i t qua b'nh loan giflp khang dinh tinh chlnh x i e cua mfl hinh v i s y tfin tgi cfla d l l m tfii u u .
K ^ LUJ^N
Vdi myc tieu thu n h i n enzyme lactase Ihfi t i i chflng L. delbrueckii ssp delbrueckii, ngufin carbon thfch h p p cho q u a t r i n h - sinh tfing h p p lactase l i glucose v d i hogl Unh lactase thu d u p c la 49673 U/g. Hoat tfnh lactase toi da dgi d u p c s a u 20 gid Ifin men l i 64829 U/g khi nhifit dfi nufli c l y l i 34,6° C, pH ban d l u 6.23 va t f Ifi c l y gifing 16%.
T A I L I ^ U T H A M K H A O '
Siham A.A I el a l , 2010, Cultural condiBon affecting the growth and production of p-galactosidase by Lactobacillus addophilus NRRL i435. Australian Joumai of Basic and Applied Sc/encos, Vol 4, 5051-5058
Mlichovi Z. et al., 2006. Cunent tr^ids of p-galactosldase appllca^on In food technology, Joumai of Food and Nutrition Researdi, Vol 45.47-54
Kim J.W, et al., 2000, Isolation'and characterization of p-galactosidase from Lactobacillus crispatus. Folia Microbiology, Voi 45, 29-34 Laxml el al., 2011, Effect of carbon and nitrogen sources on growth of Bifidobacterium anlmalis Bb12 and Lactobacillus delbrueckii ssp.
bulgaricus ATCC 11042 and producGon of p-galactosidase under drfferent culhire condihons, Intemalmnal Food Research Joumai, Vol 18,373-380
Snphannam W. el al., 2012, Medium component Improvement for p-galactosidase praducbon by a probiotic strain Lactabadllus fennentum CM33, African Joumai of Bmtechnology. Vol T l , 11242-11251
Cnstian J B. de Lima et al., 2010, The Use of Response Surface Methodology in Optimization of LacSc Acid Production: Focus on Medium Supplementation, Temperahjre and pH Control, Food Techndogy Biotedmdology. Vol 48,175-181
HQI MGHI KHOA HQC CClNG NGHF SINH HOC TOAN QUOC 2013 OPTIMIZING SOME OFJHE^CULTURAL CONDITIONS OF LACTOBACILLUS DaeRUECK/rsST^DErBRDECrarrOrOBTAIN-tAC-TASefiY-RESPeNSE SURFACE METHODOLOGY
Quach Due Tinh*, Vu T h i True P h u o n g , L e Hoa N h u , Nguyen T h u y Huong University of Technology,' Vietnam NaUonal Unh/ersiiy, Ho Chl Mnh ciiy
StJMMARY
Lactase enzyme has many important appiicatioDs in daiiy industry. For &e next step lo obtain lactase in industrial scale, the production of lactase by Lactobacillus delbrueckii ssp delbrueckii was stndied. The present study was conducted to identify conditions for the highest activity of lactase enzyme fiom Lactobacillus delbruecldi ssp delbrueckii by using response surface methodology (RSM). The highest lactase aclivi^ was obtained by using glucose as carbon source. RSM was used to investigate the effects of three fermentation parameters (temperature, inital pH and inoculation rate) on p-galactosidase enzyme production Maximuni specific enzyme activity of 64829 U/g was obtained at tlie optimum levels of process variables (34.6'' C, pH 6.23, inoculation rale 16%) Results of the statistical analysis showed that the fit of the model was good in all cases (about 95%).
Keywords: Lactase, Laclobacillus delbrueckii ssp delbrueckii, probiotic
"Authorforconespondence; Tel: 0984515235; Email: quachduclinh2110@gmail.com or tayxuyen@yahoo,com
