英语翻译Studies have indicated that the medium composition andgr

英语翻译Studies have indicated that the medium composition andgrowth conditions can influence the type and yield of biosur-factant.Carbon source influences biosurfactant synthesis byeither induction or repression.In some cases addition ofwater-immiscible substrates results in induction of biosurfac-tant production.The induction of sophorolipid synthesis byaddition of long-chain fatty acids,hydrocarbons,or glyceridesto growth media of Torulopsis magnoliae (14),of trehalolipidsynthesis in Rhodococcus erythropolis by addition of hydrocar-bons (15),and of glycolipid-EM (where EM = emulsifier) inP.aeruginosa SB-30 by addition of alkanes (16) has been re-ported.Induction also regulates synthesis of many lipopep-tide biosurfactants (17–19).Banat et al.(20) observed littlebiosurfactant production when cells were growing on a read-ily available carbon source.Only when the soluble carbon wasfully consumed and a water-immiscible hydrocarbon wasavailable was biosurfactant production triggered.A carbonsource in the medium,particularly a carbohydrate,has con-siderable bearing on the type of glycolipids formed.Suzuki etal.(21) observed that glucose,fructose,and sucrose lipids areformed by Arthrobacter paraffineus and several species ofCorynebacterium,Nocardia,and Brevibacterium during growthon the corresponding sugar.The Bacillus strain used in thisstudy is able to utilize glucose,sucrose,and sodium pyruvatefor biosurfactant production.The biosurfactant was not pro-duced when sodium acetate was used as the carbon source.The strain was able to utilize n-hexadecane and pristane forgrowth but not for biosurfactant production.Sucrose wasfound to be a suitable carbon source for maximal growth andbiosurfactant production and was studied at a concentrationof 2% in minimal medium.There is evidence that nitrogen plays an important (defi-nite) role in the production of surface-active compounds bymicroorganisms.Arthrobacter paraffineus ATCC 19558 pre-ferred ammonium to nitrate for biosurfactant production.Urea also resulted in good surfactant production (22).An in-vestigation of rhamnolipid production by Pseudomonas 44Tion olive oil showed that sodium nitrate was the best nitrogensource (23).Syldatk et al.(24) showed that nitrogen limita-tion increased the production of some biosurfactants butalso changed the composition of the biosurfactants.In thepresent study,both sodium nitrate and potassium nitrate arepreferred nitrogen sources.Bacillus subtilis MTCC 2423 wasnot able to utilize ammonium sulfate,but exhibited a prefer-ence for nitrate ions.Potassium nitrate (3g/L) was found tobe optimal for biosurfactant production.The biosurfactantproduction was ca.1.0 g/L with urea.翻译量还是比较大的，专业词汇较多，希望是生物专业的同学能帮帮忙，翻译得好的话有加分。拒绝GOOGLE，