The Process of Xylanase Production from Bacillus pumilus RXAIII-5

Volume

I , Numbti

2

The

Process

of

Xylanase

Production from

Baci~mpumilus

RXAIII-5

NUR

RICHANA1$*,

TUN

TEDJA

IRAWADI',

M.

ANWAR NUR',

ILLAH SAILAH2,

m

KHASWAR SYAMSU2

IDepartment

of

Chemistry,

F a d @

of _{Ydhemafics and Naiuml S d e n m}

'Dqmfment

ofAgrolnhstdal TechnoIogy, F~acwfly of _{Agrolmrlrrsfrial}

Technology

Insiitri Pemnian

Bogor, Darmaga

Cartrprrs, Bogor 16680, Indonesiu

The optlmum conditions for the growth

or

Bsclllns pnmllus R X A I I I - 5 (a potential xylanist producer) were nought. tbtst included trmpcraturc, pH, aeration. and agitation of the calturt batcb. Afterwards a mathematical modtl bawd on the parameter of cultivation klnttics was formulattd. At the uamc time, the rheology o f the fluid

a d COT battcrlal crltlvatlon in a biortactor was studied. The data obtained was used for cstlmatlng the 'scaling tip' of tnzyme production. The results of tbc study indicate thmt the optimum rondltion for proceraing I n 50

ml

E r l t n m t y t r flask a r t used temperature of 35 'C (308'K), pH 7, and an agitatlon rate or 140 rpm. The bigbest xylama8c activity aod Its sprciflr activity arc 297.132 U,ml-I mod 655.32 U.g-'profitin, rtnptctlvtly. Subsequent cxperimtntn In a blorcactor using all o f t h t experiment parnmtttrs mentioned above. except for the agi#ation ratt, #howl that the results a r t as follows. The highest rpcciClc growth war at 0,082 hour-' at an aeration and

a~itacloa r a t t of 0.5 vvm and 150 rpm. respectively. Based on the data of tht cultivation Irlneticn, the optlmum

coaditiona for tbt ftrmcntation in Biostat ZL-bioreictor is 1 vvm and 200 tpm of atntion and agitation, respectlvrly.

Tbc tMcltncy of substrate (Ypls) and of cell biomass (YI,,) to produce xylanase is 50.744 U.g-I mod 43.906 U.g-I,

rerptctivtly. T h t eMciency of substrate to cell production (Y*,,) is 1.178g.g-I. The liquid culttvatlon-mrdlrm h i s non-Newtonian proptrtlts. Based on a mathematical model it i s Connd that the conulsttary ladex (k congtant)

mmd index o f liquid bthavlor (11 value) are 0.179 g.crn-'.8ccond-' and 0.3212. resptttivrly. Btcoust the value or

Ocm<l amd the conetant k>O. the culture liquid i s categorized as pseudo plastic one. The Rbtynold number (NRc)

I s 6.9 x lff which indicates i t has turbulent cltrmcttristics. From a cmlcut~tion i t is louod that the power required t o run a snitably slztd impeller i a 0.228

HP

(Hornt Power) and the power ronsumption per unit volume i8

0.2265 HP.m4. A l l tbtsc valuer were u r t d Tor ncaling up xylanasc production ia the biortattor.

Key words:

Bacillus

pumilus,

xylanase,

production

Xylanase is a

group o f

extracellular enzymes which

are

able to

hydrolyze

hemicelullosic materials into xylose and

xylo-oligosaccharides.

Xylanases

show great

potential

for

industrial applications mainly for

the

bioconversion of

lignocelluloses to sugar, ethanol, and other useful

substances,

clarification

of juices

and

wines,

improving

the

nutritional quality

of silage

and

green

feed and the de-inking

processes

of

waste

papers

(Viikari et

a/.

200

1

).

The

enzymes

have

been

grouped

based

on the type

of substrate hydro1 ized.

Xylanases

are

categorized

into

three groups:

P-xy

losidase,

exoxylanase

and

endoxylanase. Endoxylanase

i s

the main

enzyme

responsible

for

the cleavage

of the linkages

with

in

the

xylan

backbone (Belfaquih

ef

al. 2002).

Only

a

few

microorganisms are capabIe of producing

xylanase

extraceluHarly.

Some

findings

indicated that bacteria (Gilbert

and

Hazlewood

1993;

Sunna

and

Antranikian 1997),

fungi

(lonukari

et

al.

2002;

Kheng

and

Omar

200S),

actinomycetes

(Ball

and

McCarthy

1989;

Begg

er

at.

2001),

and

yeast

(Hnmva

el

ai,

1984;

Liu

a

al.

1999)

were

capable

of

producing

xylanase,

Xylanase-producing alkaliphillic bacteria can

be

used

as bleaching

agent

for

paper

processing

(Ruiz-Arribas

et

al.

1995).

Cultivation of

xylanase-producing

microorganisms

in

a

liquid

medium

has

been applied widely in producing the

enyme.

There are

many

advantages in

using

a

liquid

medium,

i.e.

the type

of

component

and composition of the medium

are easy

to

adjust

to obtain the optimum conditions for

microbial

growth;

more efficient consumption of

substrate

easier in adjusting the microorganism

growth rate;

and the

risk

of

contamination is

less

compared to

using

a

solid

medium. However, the cultivation in liquid medium required

skills

and

expertise in operating

a

bioreactor for obtaining

a

high

level

of

enzyme

production. By shaking

the

liquid

medium, it is expected

that

temperature, pH, oxygen,

nutrient

supply

as

well

as

other environmental factors are

homogenous throughout the medium in

ihe

bioreactor.

The

engineering

on

the

processing of xylanase

production

is based on

the

information obtained through

studying on

the

optimization

process,

the strategy

on the

studying

optimum level of

substrate,

and

then

the

modeling

competency of the fermentation

industry.

All

these

cover

the

studies on the cultivation kinetics based

on three

rates

i.e.

the rates of biomass production, of substrate consumption

and

of enzyme production.

Production

of

xylanase from isolate bacteria capable of

utilizing

xy

Ian

for -growth substrate

as carbon

source. In

%sent address and *Corresponding author, Indonesian Center

for Agricultural Postharvest Research and Development, Pusat

general,

the

agro-residues

such

as

wheat

bran,

sugar

cane

Penelitian dan Pcngcrnbangan Pertanian. Jalan Tentara Pelajar

bagasse*

cobs

paddy

straw,

rice

husks*

and

cassava

No 12, Bogor 16 1 14. Indonesia; Phone: +62-25 1-7 1 77064,

wastes

were

found to

be

more suitable like

xylan

(Saurabh

et