单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,生物表面活性剂,生物表面活性剂,Introduction,Bios,urfactants(,amphiphilic compounds,),(,synthesized by microorganisms,),hydrophobic,(nonpolar),hydrophilic,(polar),that confer ability to accumulate between fluid phases such as oil/water or air/water,reducing the surface and interfacial tensions and forming emulsions.,household、industry and agriculture,mono-,oligo-or polysaccharides,(多糖）,peptides,（缩氨酸）,or proteins,saturated,unsaturated and hydroxylated fatty acids or fatty alcohols,Introduction Biosurfactant,生物表面活性剂课件,生物表面活性剂课件,生物表面活性剂课件,生物表面活性剂课件,生物表面活性剂课件,生物表面活性剂课件,Properties,Surface and interface activity,biodegradability,(,bioremediation,),.,emulsifying,and demulsifying ability,antimicrobial activity,PropertiesSurface and interfac,Surface and interface activity,In general,biosurfactants are more effective and efficient and their,CMC,(critical micelle concentration)is about 10-40 times lower than chemical surfactants,i.e.,less surfactant is necessary to get a maximal decrease on ST.,A good surfactant can lower surface tension(ST)of water from,72 to 35,mN/m and the interfacial tension(IT)water/hexadecane,（十六烷）,from 40 to 1 mN/m.,Surface and interface activity,The biosurfactants,accumulate at the interface between two immiscible fluids or between a fluid and a solid.,.(,figure 1,),By reducing surface(liquid-air)and interfacial(liquid-liquid)tension they reduce the repulsive forces between two dissimilar phases and allow these two phases to mix and interact more easily,The biosurfactants accumulate,Biosurfactant activities depend on the concentration of the surface-active compounds until the,critical micelle,concentration(CMC),is obtained.At concentrations above the CMC,biosurfactant molecules associate to form micelles,bilayers and vesicles(,Figure 2,).,The CMC is commonly used to measure the,efficiency,of surfactant.Efficient biosurfactants have a low CMC,which means that less biosurfactant is required to decrease the surface tension.,Biosurfactant activities depe,The biosurfactant,effectiveness,is determined by measuring its ability to change surface and interfacial tensions,stabilization of emulsions and by studying its,hydrophilic-lipophilic balance(HLB).,Emulsifiers with low HLB are lipophilic and stabilize water-in-oil emulsification,whereas emulsifiers with high HLB have the opposite effect and confer better water solubility,Low toxicity,For example:A biosurfactant from,P.aeruginosa,（绿脓假单胞菌）,（was compared with a synthetic surfactant(Marlon A-350)widely used in industry in terms of toxicity and mutagenic properties.Both assays indicated the higher toxicity and mutagenic effect of the chemical-derived surfactant whereas biosurfactant was considered slightly to non-toxic and non-mutagenic.,low or non-toxic products,and therefore,appropriate for,pharmaceutical,cosmetic and food uses,.,Low toxicity For example:A,Emulsion forming and emulsion breaking,An emulsion is a,heterogeneous system,consisting of at least one immiscible liquid intimately dispersed in another in the form of droplets,whose diameter in general exceeds 0.1 m.Emulsions have an internal or dispersed and an external or continuous phase,so there are generally two types:,oil-in-water(o/w),or,water-in-oil(w/o)emulsions,.,Such systems possess a minimal stability,which may be accentuated by additives such as surface-active agents(surfactants).Thus,stable emulsions can be produced with a life span of months and years.Biosurfactants may stabilize(,emulsifiers,)or destabilize(,de-emulsifiers,)the emulsion.High-molecular-mass biosurfactants are in general better emulsifiers than low-molecular-mass biosurfactants.,Emulsion forming and emulsion,Antimicrobial activity,A significative reduction on the mycoflora,（真菌群）,present in stored grains of corn,peanuts and cottonseeds was observed at iturin concentration of 50-100 ppm).Inactivation of enveloped virus such as herpes,（疱疹）,and retrovirus,（逆转录酶病毒）,was observed with 80 m M of surfactin,（脂肽）,.,Several biosurfactants have shown antimicrobial action against,bacteria,fungi（真菌）,algae（藻类）and viruses.,The lipopeptide iturin,（脂肽伊枯草菌素）,from,B.subtilis,（枯草芽孢杆菌）,showed potent antifungal activity.,Antimicrobial activity A,Production,Biosurfactants do not compete economically with synthetic surfactants.To reduce production costs,other carbon sources,such as,olive oil（橄榄油），mill effluent（工厂废水）,whey（乳清）,from cheese making,and,cassava flour water,（木薯粉水）,used vegetable oils,molasses（糖浆）(by-product).,Biosurfactants have been synthesized by various researchers,using different microorganisms and carbon sources,.The carbon sources used for biosurfactant production are,hydrocarbons,carbohydrates,and,vegetable oils,.,Production Biosurfactan,Production,methods,Natural biological extract method、Microorganism fermentation method、Enzyme catalytic method,Purification methods,Precipitation method、Extraction method、Superfilt