Document rBEpp7ZmEZpZMrmobreeDK060

15-103 P United States Patent ni Azarowtcz mi 3,779,066 (451 Dec. 18, 1973 154] MICRORIAL DEGRADATION OF POLYCHLORINATED BIPHENYLS pSj Inventor: Edward N. Asarowicx, Vienna, Va. (731 Alienee: KloteknlLe fntsntatlanal, Inc., Alexandria, Va. (221 Filed: Apr. 7,1972 121( Appt. No.. 242,192 (52) (SI) |381 U.S. Cl............................................ 195/2, 195/3 H Ini. Cl.................................................CUb 1/00 Field cf Search.................... 195/2. 3 H. 1. 28 ft. 195/51 ft. 82; 424/93; 210/2, 10. 11, 17 1561 3.614.204 3,634.227 Reference* CUed UNITED STATES PATENTS tO/1971 Unn......................................... 195/2 1/1972 Fittenon.......................... 195/21 ft Primary xaminer--A. Louis Monacell AjjfeMnt Examiner--R. B. Penland Attorney-- Raymond C. Stewart ct al. (571 ABSTRACT A process for the microbial degradation of poly chlorinated biphenyls (PCBs) which comprirsi treoting the PClis with certain non-pathojenic, hydrocarbon-miliring strains of Cladosporium clcdospnrioidci, Candida lipolytics. Nocardit globerula, N'ocardia rubra and/or Sacchcromyces ccrcvfcir.c until the PCBs have been substantially degraded. The process is ap plicable degrading PCBs as they may be present u pollutants or contaminants in water, in industrial efflu ents, in various land areas such as industrial sites and the like or in varied laboratory or commercial installa tions. The process may also be used to clean up r.nd degrade mixtures of PCBs and various hydrocarbon oils or petrochemicals whenever their presence consti tutes a deleterious pollution. 29 Claims, No Drawings HONS 061377 3,779.866 12 MICROBIAL DEGRADATION OF very severe and harmful effect* from PCB poisoning. fOI-YCKLOUlNATGD BIPHENYLS There is some evidence that PCBs alter liver tissue, in BACKGROUND OF THE INVENTION hibit tile growth of cultured cell* and affect a variety of enzyme systems and the genetic material of cells, but This invention relate* to a process Tor the microbial 5 in most cases, the mechanism of action is tiili uncer degradation of polychlorinated biphenyls. More partic tain. In any event, the presence of PCBs in the environ ularly, it relate* to a method for degrading poly* ment has been a great concern to scientists and other chlorinated biphenyl* by mean* of microorganisms in people concerned with health, rifely and welfare, and order to clean tip and eliminate such organic pollutant* there has been n great need for the development of a a* they may occur in the open tea, inland fresh waters, 10 procedure for degrading these substances. tidal pools, harbor* ir.d the like, industrial effluent dis Accordingly, one of the objects of the present inven charge*. sewage and other pipeline systems, form soil tion is to provide a method for degrading poly or other land araa* including industrial sites, etc.. The chlorinated biphenyls and similar halogenatcd mole invention is applicable not only for cleaning up poly cules. such as DDT. wherever they mr.y appear as con chlorinated biphenyls as contaminants and pollutants I) taminants or pollutants. in open environmental systems, but also in closed sys tems as, for example, in industrial, commercial or gov Another object of the present invention is to provide a process for the microbial degradation of poly ernment plants and instillations and in various labora chlorinated biphenyls wherever desired, for exomple, tory operations. as a means of cleaning up closed and open waters, in Environmental elesn-up is of much concern to the 20 dustrial effluent discharges, polluted marshlands, estu country and to the world today. Polychlorinated biphe aries. marine environments, disposal lagoons, contami nyls (hereinafter referred to as PCDs) are industrial nated industrial areas and farmlands, and in other situa chemicals that are widely used as plasticizers, fire retar tions where PCBs may become accumulated. dant paint ingredients, hydraulic fluids and heat ex A further object of the invention is to provide a pro change fluids. They have recently been detected in var 2S cedure for degrading polychlorinated biphenyls read ious water sources, in human tissue and in many species of birds and fish. Being relatively heavy organic male- ily, efficiently and relatively economically. A still further object of the invention is to provide mi cults, PCBs persist indefinitely under natural condi croorganisms that are capable of degrading poly tions. Moreover, they tend to accumulate in the food chlorinated biphenyls, leaving a detoxified and benefi chain, and once ingested, they are stored in (he tissues 30 cial cell mass, these microorganisms being completely of birds, mammals and fish used as human food. As non-pathogenic to marine fauna and flora, humans and with many other chlorinated hydrocarbons, such as animals. DOT, even small dosages of PCBs can be toxic. Yet another object of the invention to provide a PCBs are relatively inert compounds that have low method for the degradation of polychlorinated biphe solubilities in water. The commercially produced PCBs 35 nyls wherein there is no need for the handling, trans we actually mixtures of many of the isomers which are porting and storage of heavy bulky equipment. possible among the various combinations of chlori nated products that can be obtained from the chlorina These and other objects and advantages of the pres ent invention will beeome apparent to those skilled in tion of biphenyl. The most common industrial mixtures the art from a consideration of the following specifica contain between about 40 and 60 percent by weight of 40 tion and claims. chlorine, but the isometric composition thereof is rela tively unknown. However, the more highly chlorineted SUMMARY OF THE INVENTION PCBs appear to persist in the environment for the lon In accordance with the present invention, the above gest time. objectives are attained and an advantageous procedure PCBs are widely used as dielectric fluids in capacitors 45 for the microbial degradation of polychlorinated biphe and transformers, as hydraulic fluids, as heat transfer nyls has been discovered employing particular strains agents and as plasticisers and solvents in various adhe of microorganisms. The distinct, unique advantage of sives. sealants, paints and printing inks. Mott of the re the present invention is that all of the materials used lease of PCBs into the environment probly occurs from are derived orginalty from edible substances which ate industrial effluent discharges end dumping and leakage SO not toxic. It is applicable equally to the degradation of of lubricants, hydraulic fluids and heat transfer fluids industrial wastes in general u well as to the degrada into the waterways and soil, from materiel* containing tion of PCBs in open and dosed aqueous systems no MOMS 061378 PCBs as e plasticiser into the atmosphere, and as a re matter how the system was contaminated and polluted. sult of leaching from dumps and landfill*. Although there is some evidence that PCBs can be 55 In the present invention, advantage has been taken of judiciously choosing microorganisms which are capa deehlurinated by ultraviolet light and, thus, lead to the ble of degrading PCBs and using them as a carbon formation of hydroxyl derivatives and other polar com source for growth. pounds that are more readily degradable, PCS* are The present invention comprises a purely biological very persistent end ere extremely difficult to degrade once they are present in the environment. PCB residues 60 process in which certain selected microorganisms break down the PCBs and convert the contaminants have been particularly noted in fish, birds and mam into masses of edible, non-toxic cells. >.e., a protein mals, which include those used for human food as well mass. In an outdoor application, this cell mass can be as the wild animets. Although the data are incomplete channeled into the food chain to feed higher forms of at the present time, there is significant evidence that most humans have some residues of PCBs in their tis 65 life and, achieved thus, a very advantageous end result is in addition to-solving the problem of PCB sues. The effect on humans of such residues is also un contamination. There is no need for ancillary clean-up clear at the present time, but some evidence indicates operations when PCBs are degraded in accordance 3,779,866 34 with (he invention and, a* pointed out above, there is large quantities of the cultures. If necessary, an anti Ino no need for the handling, transporting and storing foam agent can be employed therein, for example. Dow of heuvy, bulky equipment. Antifoam A, or crude oil. The following microorganisms, all completely novel Hence, either a synthetic culture medium or a natural and unohvious, ate utilized in the present invention. 5 nutrient medium is suitable for the growth of the micro These microorganisms are special rpecict which have organism 'train* employed in the present invention a* been adapted to r.chieve the objectives of the invciitinn. They have been deposited with the American long as it contains the essential nutrients for the growth of the particular microorennism strain or strain* used. Type Culture Collection in Kocl.villc, Maryland end Such nutrients arc well known in the art and include have been given the designated ATCC catulogue num 1 substances such as a carbon source, a nitrogen souice. ber*. ' inorganic compounds and the like which ire utilized by Cladosporium clxdosporioides (HI 3002) ATCC the microorganiKms employed in appropriate amounts. 2025! Candida lipolytica (El 2002) ATCC 202S5 The microorganisms used in the present invention grow and survive in an aqueous nutrient medium eon- Nocardia globerula (Dl 1039) ATCC 21505 Nocardia mhr.i (Dl 1002) ATCC 21508 I* taining a hydrocarbon or a mixture of hydrocarbons us the main carbon source. Such hydrocarbons include Saccharomyccs ccrcvisiae (bl 2009) ATCC 20252 straight and branched-chain paixffins (alkanes) rang The characteristics and properties of these microor ing from gaseous alkanes, such as methane and pro ganisms are dtr.ciibed in copsndmg application Scr. pane, liquid or semi-solid alkanes, such a n-pentane, No. 43,226, filed on June 3, 1970, entitled "Microbial 20 n-octanc. n-dccane, n-dodecane, n-hexadecanc, iso Degradation of Petroleum". pentane, isooctane, and including long-chain solid par Various media can be employed in handling these affins having high melting points, cycloparaffins such as cultures. All or the microorganism* employed in the cyclohexane and cyclooctane, straight- and branched- present invention will grow on media with 100 percent 2} chain olefins such as pentcnc-2, hetene-l, octene-l. marine water, with pan marine water and pan tap wa ter, or in distilled water. The following medium bps octcne-2. etc., cycloolefms such as cyclohexene, aro matic hydrocarbons such as benzene, o-xylene, naph been found lo be quite satisfactory as a general use, all thalene. phenamhrenes, anthracenes, etc . and mix purpose medium for maintaining stock cultures: tures thereof, as well as mixed hydrocarbons such as All-Purpose Medium kerosene, light oils, heavy oils, paraffin oils, petroleum Heart infusion broth (Difco) -- 23.0 g. Yeast extract (Difco) -- 3.0 g. Glycerol -- 5.0 ml. Glucose -- SjO g. Agar -- 15.0 g. Water -- 1000 ml. crudes, jet fuels, gasoline, etc. Other organic sub stances. such as alcohols, aldehydes, ketones, organic acids, phenctics and aromatic heterocyclic and carbocyclic compounds, are utilized by the microorganisms 3) described in the present application cation. Small amounts of other carbon sources such as car The standard Bushnell-Haas Hroth has been found to be quite suitable as a growth medium on the laboratory bohydrates, for example, glucose, fructose, maltose, sucrose, starch, starch hydrolysate, molasses, etc., or scale. A typical medium comprises the following ingre any other suitable carbon source such as glycerol. man- dients: eo nitol, sorbitol, organic acids, etc. may be used in the Yeast-nitrogen base (Difco) ~ 1.0 g. Yeast extract (Difco) -- 1,0 g. culture medium along with the hydrocarbon. These substances may be used either singly or in mixtures of MgSO - 0.2 g two or more. CaO, - 0.02 g. As a nitrogen source, various kinds of inorganic or KH'PO* Monobasic -- 1.0 g. 45 organic salts or compounds, such as urea or ammonium K,HPO,, Dibasic - 1.0 g. Mils such as ammonium chloride, ammonium sulfate, NHNO, - 1.0 g. `ammonium nitrate, ammonium phosphate, etc., or one FeCt, - 0.05 gr __or more than one amino acid or crude protein mixed m Bromthymol blue -- 0.08 g. combination, or natural substances containing nitre- Water - 1000 ml. 50 gen, such as comstecp liquor, yeast extract, meat ex The following medium has been found to be particu tract, fish meal, peptone, bouillon, casein hydrolysates, larly advantageous for the large-scale production of the fish solubles, rice bran extract, etc., may be employed. desired cultures: These substances may also be used either singly or m Skim milk (0.4 percent) -- 2.0 Iba. Cottonseed meal (1.8 percent) -- 9.0 lbs. combinations of two or more. ** Inorganic compounds which may be added to the cul Marine Salts (0.02 percent) -- 0.1 lb. ture medium include magnesium sulfate, sodium phos <NH)'HPO,. Dibasic (0.1 percent) -- 0.5 lb. phate, potassium dihydrogen phosphate, potassium Hydrocarbon <0.44 percent) -- 2.2 ibt. monohydrogen phosphate, iron sulfate or other iron Tap Water -- 60.0 gal. aalts such a* ferric trichloride, manganese chloride, cal- Instead of the marine salts and tap water, native sea 0 cium chloride, sodium chloride, ammonium nitrate, water can be used in the above medium. Aeration it etc.. usually provided lo supply oxygen to the fermentor ves The microorganisms employed in the present inven sel or lank. Generally, the microorganism eeils are bar- tion are cultured under aerobic conditions, such as aer vested after about three or four days of cultivation. A obic shaking of the culture or with stirring and aeratior large batch vessel or fermentor seeded with a young 5 of a submerged culture, at a temperature of, for exam culture equivalent to about 2 percent or more of the ple, about S* to 35*C., preferably 28*-30*C., and at a iota! capacity of the fermentor is used for producing pH of, for example, about S to 8, preferably 7-7.6 The MOMS 061379 3,779,866 56 microorganisms are harvested at an appropriate time ATCC 21505, Nocardia rubra ATCC 21308 and Sccc- and are used at ditsussed below. hiromycc* cerevimc ATCC 20252 is inoculated into DETAll.nO DESCRIPTION OF THE PREFERRED EMBODIMENTS a 250 ml. l.rlcnmcyer flask containing 0.2 percent by weight of Pydruul 3 l 2 A tn 100 ml. of the describ'd me s dium. the flunk is shaken for three duy* on u huker ut The process of the invention can be used to remove ?7*C., end the resulting cell mass in removed from the polychlorinated biphenyl* front locations wherever its flask. Analysis of the remaining liquid by mean* of $ a* pretence constitute* a deleterious pollution. Thus, with chrumaUq-Tiphy shows that the PCD concentration in (hi* process, it become* postib'e to clean up and de less than 0.3 p.p.m.. grade PClit on the open tea. In harbors, fiver* and 10 The same results are obtained when the procedure is oilier inland waters, on vaiious kind* of beaches and carried nut using other mixtures of two or more of laid soils, in industrial effluent systems, in sewage disposal microorganism*. Hence, the described microorganisms systems, in various laboratory systems, etc.. may be used cither singly or in various combinations of The following examples are given merely as illustra two or mure to degrade PCBs in accordance with the tive of the present invention and arc not to be consid IS objectives of the invention. ered as limiting. Generally, the degradation of PCT.s on a large scale EXAMPLE l is conducted in a multi-tank installation. Less often, degradation is done in outdoor environments. In open pydraul 312 A, a hydraulic fluid containing a mixture water applications, it it quite feasible to teed or dis of PCBs and an oil-soluble dye, is poured into five sepa 20 perse the microorganism* employed by means of boats, rate 250 ml. Krlenmeyer flasks to give a concentration aircraft ot other vehicles as appropriate. Even thou;. It of 0.2 percent by weight of the Pydraul 3I2A in the the PCBs arc heavier then water, degradation lakes flasks, which each contain 100 ml. of the following me place since the microorganisms become dirptred dium: Yeast-nitrogen base (Difco) -- 0.1 g. downward with lime to the benthic mud. The mixture 25 employed preferably includes a cellulose absorbent Yeast extract (Difco) -- 0.1 g. such as. for example, straw, bagasse, pine berk mulch, Peanut oil (0.2%) -- 2.0 ml. sawdust or other forest or agricultural products. Addi MgSO, - 0.02 g. * tive nutrients for the microorganisms are also mixed CaCI, - 0.002 g. KH,PO, Monobasic - 0.1 g. with the absorbent, such as cottonseed protein or other 30 inetpensive agricultural by-products and inorganic K(HPO, Dibasic - 0.1 g. salts of nitrogen and phosphorus. The process m appli NHNO,- 0.1 g. cable from just above freezing temperature (shout FeCI, - 0.005 g. 4*C.) to about 39*C.. The PCB degradation will begin Bromthymoi blue -- 0.008 g. Distilled water -- to make 1000 ml. upon spreading the mixture on the surface of the water. 35 Complete degradation may taka place as rarly as three The first flask it inoculated with Cladosporium cla- days to one week, but could lake longer depending dotporioidet ATCC 20351, the second flask with Can upon the PCB concentration and the temperature eon. dida lipolytica ATCC 20255, the third flask with No- dilions. Of course, it is not necessary to use an absor eardia globerula ATCC 21505, the fourth flask with bent, and the microorganisms can be used as a foam or Nocardia rubra ATCC 21508 and the fifth flask with 40 In a slurry, powdered or pelletized form with added nu Saccharomyees cerevitiaa ATCC 20252. The flasks are trients. ahaken at 170 r.p.m. at 27*C. for three days. At the end Withjui application on dry or damp soil, the mixture of three days, a visual examination of the flasks shows of microorganisms and nutrients can be applied to the a disappearance of the globulee of hydraulic fluid, oil and the mixture will work aerobically and anaero which are heavier than water. The resulting cell mass 45 bically to degrade the contaminant PCBs. This proce la separated from aach of the fluke, and the remaining dure is especially effective on extremely wet surfaces liquid la analysed by meant of gat chromatography. such as marsh lands, farm lands or industrial land sites The gu chromatographic analysis shows that the PCB such as trucking areas and railroad sidings. concentration in.*ach flask is not detectable and is thus The most practical application of the present inven lees than 0.3 p.p.m. 50 tion involves the degradation of PCBs in waste materi EXAMPLE 2 als from industrial plants or other types of commercial installations, where PCBs arc spilled accidentally by A 2S0 ml. Erlenmeycr flask containing 0.2 percent leakage from heat exchangers. In this application, the by weight of Pydraul 312A in the same medium as de scribed in Exsmple 1 is inoculated with a mixture of 55 effluent material to be degraded can be placed into large holding tanks, for example, and the mixture of mi Cladosporium cladosporioide* ATCC 20251 and Can croorganisms and nutrients added thereto, whereby dida lipolytica ATCC 20255. The flask is shaken at 170 degradation will take place as described above. Stirring r.p.m. at 27*C. for three days. A visual examination of and aeration of the mixture inside the tank is advanta Ihs flask shows a disappearance of the hydraulic fluid, and after separation of the resulting cell mass, gu chro 60 geously employed to provide a more rapid degradation. A single lank system may be used, or a rmilti-uink sys matographic analysis indicates that the PCB concentra tem may be employed whcicin the effluent material is tion is less than 0.3 p.p.m. moved from tank to tank at specified times. Additional microorganism cultures and nutrients fur the microor EXAMPLE 3 In the same manner as described in Example 1, a mix 65 ganisms may be added to the subsequent tanks as de sired, for example, to obtain a desired or necessary ture of Cladoiporium ciadocporioidet ATCC 20251, level of PCB concentration. The degraded effluent, for Candida lipolytica ATCC 20255, Nocardia globerula example, may then be discharged into a lake, stream M0NS 061380 3,779,866 78 marsh. tc., or the water miy bo recirculated within the Ctnitm selected from the group consisting of non- Industrial plant. pathogenic, celt-mass producing, hydrocnrbon-uliilfin* Since the microorfinlimi of the pre*srt invention drains cf C'lrdo*-orium cladospoi loi.tcs. Candida lipo- re alio c?pable of der.rcdinjr petroleum and various 1} tie*, Nocardin f lobarula, Nncurd'd rubra and Saccha- petrochemical tubstr.ncet. at dssetibad in copendis 3 roinycci cerevixuit for sufficient time until the poly* application Serial Nun-bar 43,526. the process of the chlorinate biphenyls have been cbiuuiti.'.lly degraded. preterit invention may bo employed with tlTIuer.u which contain petroleum or petrochemical ecntr.mi- 2. The procf.s of claim l, wherein said microorgan ism is mixed with o celluJotic msteri-f. ntnU r. well t.v PCBs, for o.rmple, emtikifmd cutting 3. The pjocets of claim t, wherein raid microrrrn- oils or rolling mill eoohj-u.. The degrftdr.tion of one 10 inn is mixed with a ccllulozic material, a nitro;un substance U not effected by the degrotUticn of other source nnd a phosphorus source. substances, end a compile cleon-vp operation of, for 4. The process of claim I, wherein mid microorgan-- iTampIs, total Industrial waste problem, ern be effec Itm is added to an aqueous solution containing the tuated in this manner. polychlorinated bif-3-.cnyla in slurry ferm in an amount The microorganism or mixture of microorganism* is 13 of approximately I percent to S percent by volume. *ufvant**couly added in slurry form In an amount of 5. The procerj of claim 2, wherein Mid cellulosic ma about I percent to S percent, preferably 2 percent, by volume to an uquaous illusion conuinir* (.bout 10 teria) is selected from the group consisting of sawdust, pine bark, wood Dour, cotton lir.ttr*. cottonseed hulls, p.p.m. to shout 1$ percent by weight of I'Cts for opti straw, begaxse. mi.rh hay and shredded paper. mum depredation action. If the mixture to be degrrded 20 6. The process of claim 3, wherein said nitrogen eontains oil end other orpanic pollutant* beside* PCD*, a concentration of several percent (W/V) of microor source is cottonseed protein 7. The process of claim l, wherein said microorgan ganism-nutrient mixture it ucually sufficient to be ef ism is employed in a slurry form. fective. About 1 percent to 5 percent by weight t desir C. The process of claim 1, wherein sr.id microorgan able. 23 ism is employed in s pelletised form. It Is to tie noted that a belanccd nutritional medium, 9. The process of claim }, wherein said microorgan including carbon source end additive nitrogen end ism is employed in * powdered form. phosphorous nutrients, li provided for the microorgan 10. The process of claim 1, wherein said microorgan isms employed. Since the additives used are of agricul ism is employed in the form of a foam. tural or forest sources, they are safe and non-toxic. Ac 30 11. A process for (he microbial degradation of poly, cordingly, the entire procedure k safe and non-toxic chlorinated biphenyls which comprises treating st;>d since the microorganisms themselves are not toxic to polychlorinated biphenyls with at leir.t one microor humans, imimals or fish. The carbon source can be ganism selected from the group conr.itinp. of CtrdospoPCBi elone, or a mixture of PCBs and other hydrocar hum cladocporioides ATCC 20251, Candida iipolytiea bons it concentrations of trace up to about I5 percent 33 ATCC 20255, Nocardia gioberula ATCC 21505, No- by weight. It can thus be seen that the present invention pro ctrdio rubra ATCC 21508, and Saccharomycet cerrvitiae ATCC 20252 for s sufficient lime until the poly vides a desirable nd advantageous process for degrad chlorinated biphenyls have been substantially de ing and cleaning up polychlorinated biphenyls, es well graded. as petroleum or petrochemical pollutants and contami <0 12. The process of claim 11, wherein said microor nant*. by means of microbial degradation, so ea to re ganism is mixed with a celluloric material. store the polluted material to an ecolorically-clean 13. The process of claim II, wherein said microor condition. This procedure is earned out tsfely and rela ganism it mixed with a ccllulosic material, a nitrogen tively economically without any harm whatsoever to source end t phosphorus source. human, animal or marine Ufa. 43 14. The process of eleim 11, wherein the poly It Is to be understood that the pritanl invention em braces the use not only of the sbevidturlbed micro chlorinated biphenyls are contained in sji aqueous so lution and said microorganism is added thereto in organisms, which are given merely for illustrative pur slurry form in an amount of about I percent to S per poses, but it also includes die use of mutants produced from the specifically enumerated mlcroorpnnisms, pro 30 cent by volume. 15. The process of claim 14, wherein about 2 percent viding that they perform the same function. It is to be by volume of the microorganism slurry ij added u> the T8ET90 SNOW farther underetood that die invention includes the use solution of polychlromated biphenyls. of subcultures obtained by various standard microbio 16. The process of claim 14, wherein the concentra logical techniques. Such mutants and/or subcultures may differ in certain respects from the above-described S3 tion of polychlorinated biphenyls in said aqueous solu tion is about 10 p.p.m. to about IS percent by weight. now strains, but they will work to degrade PCD* in ap proximately the soma munnar as ditclostd above. 17. The process of claim 12, wherein said cellulitic material is crlrctcd from the group consisting of saw The invention being thus described, it will he obvious dust, pine bark, wood flour, cotton linters, cottonseed that the coma may b varied In many ways. Such varia 60 hulls, straw, b.'.^oe, marsh hay end thrrdded ptper. tions are not to be refsrdod as a departure from the 1G. The process of claim 13, wherein said nitrogen spirit and scops of the invention, and nil such modifica source is cottonseed protein. tions as would be obvious to one skilled in the art are 19. The process of claim II, wherein said microor intended to bo included herein. ' ganism is employed in a slurry form. I claim: 65 20. The process of cluim 11, wherein said microor I, A process for the microbial degradation of poly ganism is employed in a pelletized form. chlorinated biphenyl* which comprises treating acid 21. The pro-CMis of claim 11, wherein said microor polychlorinated biphenyls with at least one mlcroor- ganism is employed in a powdered form. 3.779,866 10 22. The process of claim 11, wherein stid microor* ganism is Nocardia globerula ATCC 21505. ganism is employed in the form of a foam. 27. The process of claim It, wherein said microor 23. The process of cluim 11, wherein said microor ganism it Nocardia rubra ATCC 2150(1. ganism is added to the polychlorinated biphenyls at 2(1. The process of claim II, wherein said microor temperature of approximately 4*C. to approximately 5 ganism in Saccharomyccs vercvmti ATCC 20252. 3VT,, 24. The process of claim 11, wherein said microor 29. The process of claim II, wherein the poly, ganism is Ctodospnrium cladosporioidcs ATCC 2025I. chlorinated biphenyls are contained in an aqueous so 25. T he process of claim 11, wherein said microogan- lution which additionally contains hydrocarbon oils or ism is C'nr. Jida lipolytics ATCC 20255. IU other petrochemicals. 2ft. The process of claim 11, wherein said microor- IS 20 2S 30 33 40 43 50 S3 40 43 M0NS 06X382