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Optimization condition of the biosurfactants production by P. aeruginosa using

soybean oil as substrate has been examined. The media containing 10% v/v of the soybean oil

and days of the fermentation time !as the optimum condition for the biosurfactants

production. The extraction techni"ue using different solvent polarity #nhexane$ chloroform$

ethyl acetate and buthanol$ respectively !as applied for the isolation of the biosurfactants.

The biosurfactant !as found in the extract chloroform of the crude biospasoy #biosurfactantsobtained from soybean oil as substrate !hich then is called chlo&biospasoy. The chlo&

biospasoy !as identified as rhamnolipids !hich had oil in !ater #o/! emulsion type$ had the

'(' of )0 mg/* and could reduced the surface tension of the !ater from +, m-/m to ,

m-/m. The chlo&biospasoy could be used as an emulsifier to form emulsion bet!een !ater

and hydrocarbon such as palm oil$ benzene$ premium or toluene !ith various stability. The

results indicated that chlobiospasoy could be used as an emulsifying and emulsion&stabilizing

agent.

urfactants are a !ide class of amphypatic molecules that are capable to reduce

surface and/or interfacial tension bet!een gases$ li"uids and solids$ thus$ these substances

have been used in an extremely variety of products and processes in chemical$ food and

pharmaceutical industries. The toxicity$ lo! biodegradability and effectiveness in a narro!p and temperature range of synthetic surface&active compounds increased the interesting on

the biosurfactants. These substances present ecological acceptance and effectiveness in a

!ide range of p and temperature. esides$ the surface and interfacial activities$ some of the

biosurfactants presented antifungal$ anti&viral and metal sorption capacities and are used in

the petroleum industry to increase oil recovery processes

213. (ost biosurfactants are complex molecules$ comprising different structures that

include peptides$ glycolipids$ fatty acids and phospholipids 2,3. iosurfactants are produced

by a !ide variety of diverse microorganisms and have very different chemical structures and

surface properties depending on the physical and chemical conditions under !hich they are

gro!n 243. 5part from the influence of different microorganisms$ biosurfactant can be

produced from a variety of rene!able substrates$ such as carbohydrates$ lipids and proteins

263. The structure of biosurfactant reflects the structure of the substrate provided in the culture

and changing the substrate often alters the structure$ and hence the properties of the product.

7egetable oils have been used as substrates in producing biosurfactants. 8lucose and/or palm

oil have been used for the production of sophorolipids by Candida bombicola 23. oybean

olive$ castor or sunflo!er oil as substrate has been used for the production of biosurfactants

by Serratia marcescens23.

(icrobiological conversion of oleic acid to hydroxy fatty acid by thePseudomonas

!as reported in the 0s 2+&93. The conversion of oleic acid to 10& hydroxystearic acid #10&

5 !as observed by :allen et al. to reach a 16% yield 293. 10&5 produced by

Pseudomonas sp. !as found to be stereospecific$ the hydroxy group having ;&configuration2)3.Pseudomonas sp. 6,5,$ !hen cultivated in a mineral salt medium !ith olive oil as a sole

carbon source< produced dihydroxyoctadecenoic acid 2103. The bioconversion of another

Pseudomonas sp. 5fforded +$10 dihydroxy&)#=&octadecenoic acid #;O; from oleic acid.

The maximal yield of ;O; !as +,% 211$1,3. oybean oil contain &90% of unsaturated

fatty acids$ !hich are oleic acid #6,&,%$ linoleic acid #,1& 46% and linolenic acid #0&1%

2143. The ob>ective of this research is to produce biosurfactant and characterize it based on

microbial production byP.aeruginosa using soybean oil as substrate.

Isolation of Biosurfactants

The culture supernatant containing biosurfactants !as separated from the cells by

centrifugation at 1,.000 g for ,0 minutes. The extraction techni"ue using different solvent

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polarity #n&hexane$ chloroform$ ethyl acetate and buthanol$ respectively !ere applied to the

cell&free culture. The extract !as evaporated to get biosurfactants free of the solvent.

CMC Value of Biosurfactants

The biosurfactants concentrations !ere determined by diluting the purified biosurfactants

until reaching the '('$ !hich !as determined by plotting the surface tension as a functionof the biosurfactants concentration$ and then the surface tension at that point !as designated

as ?cmc.

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Figure 1. 8ro!th and biosurfactants production of P. aeruginosa@ #a optical density$ #b

emulsification index and #c. surface tension #-@ nutrient broth< -%@- A % v/v

soybean oil< -10%@ - A 10% v/vsoybean oil< -,0%@ - A ,0% v/v soybean oil.

The biosurfactants could be produced based on microbial production by P. aeruginosa using

soybean oil as substrate. The media containing 10% v/v of the soybean oil and days of the

fermentation time !ere the best condition for the biosurfactants production. The extraction

techni"ue using different solvent polarity #n&hexane$ chloroform$ ethyl acetate and buthanol$

respectively !ere applied for the partial purification of the biosurfactants. The biosurfactant

!as in the extract chloroform of the crude biospasoy #chlo&biospasoy. The chlo&biospasoy

!as identified as rhamnolipids. The chlo&biospasoy had oil in !ater #o/! emulsion type$ the

'(' of )0 mg/* and reduced the surface tension of the !ater from +, m-/m to , m-/m.

The chlo&biospasoy could be used as an emulsifier to form emulsion bet!een !ater and

hydrocarbon such as palm oil$ benzene$ premium or toluene !ith various stability.