FORM 2 THE PATENTS ACT 1970 (39 of 1970) & The Patents [Amendment] Rules, 2006 PROVISIONAL SPECIFICATION (See section 10 and rule 13) 1. TITLE OF THE INVENTION Process for Upgrading of Liquid Hydrocarbon Fuels 2. APPLICANT NAME : Indian Oil Corporation Limited NATIONALITY : IN ADDRESS : G-9, Ali.Yavar Jung Marg, Bandra (East), Mumbai-400 051 (IN) 3. PREAMBLE TO THE DESCRIPTION PROVISIONAL The following specification describes the invention : FIELD OF THE INVENTION This invention relates to a process for upgrading of liquid hydrocarbon fuels with respect to reducing aromatic, sulfur and nitrogen content through the addition of a biocatalyst, as well as the process to prepare the biocatalyst. BACKGROUND OF THE INVENTION This invention relates to a process for reducing aromatic, sulfur and nitrogen content of crude oil and liquid fuels through the addition of a biocatalyst, as well as the process to prepare the biocatalyst. Crude oils and most refined products contain complex mixtures of aromatic hydrocarbons and heterocycles. The aromatics found in petroleum and the middle distillates are divided into four groups: Monoaromatics, Diaromatics, Triaromatics; Polycyclic aromatics. Unsubstituted aromatics include benzene, naphthalene and phenanthrene, representing the mono-aromatics and di- and tricyclic polyaromatic hydrocarbons (PAH) respectively, as well as higher molecular weight PAH. Homologous series of alkyl-substituted aromatics are also present, such as toluene and the isomers of xylene, methyl- and ethylnaphthalenes. Aromatic heterocycles with N-, S- and 0- substitutions are represented by carbazole, dibenzothiophene and dibenzofuran, among others, and these also occur as families of alkyl homologues. Aromatic hydrocarbons and heterocycles adversely affect several stages of petroleum production, handling, and processing. Homologous series of aromatic hydrocarbons and heterocycles occur in varying proportions in crude oils and their refined products, depending on the source of the oil and the refining process applied. Aromatic compounds influence the persistence and toxicity of oils spilled in the environment and have poor combustion characteristics in diesel engines, including low cetane number and high particulate matter (soot) formation. During refinining, nitrogen heterocycles (e.g., carbazoles) inactivate chemical catalysts, interfere with catalytic hydro desulfurization and consume large amounts of H2. As well, combustion of fuels containing S and N heteroatoms produces S0X and NOx in emissions implicated in acid rain. Effective and cost-efficient conversion of aromatic hydrocarbons and heterocycles in crude oils and fuels therefore is desirable from an environmental viewpoint and is of intrest to the refining industry. Hydrotreating is commonly used in refinery to reduce the aromatic, sulfur and nitrogen content. Aromatics are commonly "cracked" in conventional refining by high temperature; high pressure catalytic hydrogenation to saturate and break the aromatic rings. This thermochemical technology has several problems including unfavourable reaction kinetics, high consumption of thermal energy and hydrogen (which contributes to greenhouse gases and other emissions), and production of less desirable side-products such as gaseous hydrocarbons through non-specific reactions. Several microbes are known to have activity against PAH and heterocycles especially aromatic ring opening and hydroxylation activity. These abilities may be exploited for dearomatization, desulffurization and denitrogenation of crude oil and distillates. A biocatalyst with ability to oxidixe and add polarity in the aromatics and heterocyclic aromatic compounds by oxidative enzymatic reactions is achieved by pre-grown whole cell biocatalysts. The biological processes specifically without carbon loss would oxidize the aromatic substrates present in crude oil or middle distillate fractions. These polar oxidized products may be subjected to extraction under mild conditions. The biological processing of aromatics/heterocyclic is cost effective and eco-friendly as the processes takes place under near-ambient temperature and pressure conditions. Aromatics are commonly "cracked" in conventional refining by high temperature; high pressure catalytic hydrogenation to saturate and break the aromatic rings. This thermochemical technology has several problems including unfavourable. reaction kinetics, high consumption of thermal energy and hydrogen (which contributes to greenhouse gases and other emissions), and production of less desirable side-products such as gaseous hydrocarbons through non-specific reactions. The purpose of this invention is to provide a method for upgrading of crude oil and liquid fuel through the addition of a biocatalyst as well as provide the bioactive material and the process for the preparation of the same. The biocatalyst and process disclosed in this invention reduce the aromatic content, sulfur content and nitrogen content of the liquid fuel and crude oil. Other purpose and advantages of this invention will be indicated as shown below: SUMMARY OF THE INVENTION The present invention is a process for transforming aromatic organic compounds and resource materials. The process includes the steps of contacting an organic material selected from the group consisting of single and/or multi-ring aromatic compounds and alkylaromatic compounds, and their heteroatom-containing analogues, crude oil, petroleum, petrochemical streams, liquid fuels , shale oils, heavy oils and bitumens with a microorganism or enzymes in order to increase its polarity by specifically oxidising the aroamtics and hetrocycles with out carbon loss, followed by the removing the oxidized aromatics and heterocyclic from fuel by a liquid-liquid countercurrent extraction with polar solvent. This process includes the stages of: 1. Selecting the biological material for the preparation of biocatalyst 2. Contacing the biocatalyst with contacting an organic material selected from the group consisting of single and/or multi-ring aromatic compounds and alkylaromatic compounds, and their heteroatom-containing analogues, crude oil, petroleum, petrochemical streams, liquid fuels , shale oils, heavy oils and bitumens 3. Subjecting the mixture of biocatalyst and fuel to a process of bioconversion, separation, recovery and 4. Removing the oxidized aromatics and heterocyclic from fuel by a liquid-liquid countercurrent extraction with polar solvent. The US patent 5,510,265 relates to a method for the deep desulfurization of a liquid fossil fuel containing organic sulfur comprising aromatic sulfur-bearing heterocycles is described, wherein the fossil fuel is (a) subjected to hydrodesulfurization or microbial desulfurization, (b) contacted with a biocatalyst in an aqueous medium in an amount and under conditions sufficient for the conversion of aromatic sulfur-bearing heterocycles to inorganic sulfur, wherein the biocatalyst comprises bacteria or a substantially cell-free preparation thereof having the capability of the parent microorganism for catalyzing the removal of sulfur from aromatic sulfur-bearing heterocycles, thereby preparing a deeply desulfurized fossil fuel; and (c) separated from the aqueous medium. The U.S. Pat. No. 5,910,440 discloses a process to remove organic sulfur from organic compounds and organic carbonaceous fuel substrates containing sulfur compounds having sulfur-carbon bonds is disclosed. The steps of the process include oxidizing the sulfur species to the sulfone and/or sulfoxide form, and reacting the^sulfone and/or sulfoxide form in an aqueous media of the reacting step including a hydride transfer reducing agent. In a particular embodiment, the reducing agent is sodium formate, the oxidizing agent is a microorganism as exemplified by Rhodococcus species ATCC 55309 or Rhodococcus species ATCC 55310 or combinations thereof. The US patent 5593889 discloses simple and effective biochemical process solves the problems associated with sulfur in bitumen by removing sulfur from active participation in SO.sub.x -producing combustion reactions. In one aspect, an emulsion of bitumen and water is contacted with a microbiological desulfurization agent for a time and under conditions effective to reduce the oxidizable sulfur content of the bitumen. The preferred agents do not affect the heating value of the fuel, but selectively oxidize organic sulfur to water-soluble sulfates which can either be physically removed or chemically bound so that they do not cause SO.sub.x production. Multistage reaction is employed to enhance sulfur removal. United States Patent 5,985,650 describes a method for enhancing the rate of desulfurizing a fossil fuel containing organic sulfur compounds, comprising the steps of: a) contacting the fossil fuel with an aqueous phase containing a biocatalyst capable of cleaving carbon-sulfur bonds and a rate-enhancing amount of a flavoprotein, thereby forming a fossil fuel and aqueous phase mixture; b) maintaining the mixture of step (a) under conditions sufficient for cleavage of the carbon-sulfur bonds of the organic sulfur molecules by the biocatalyst, thereby resulting in a fossil fuel having a reduced organic sulfur content; and c) separating the fossil fuel having a reduced organic sulfur content from the resulting aqueous phase. United States Patent 5,958,224 relates to a process for removing hard sulfurs from hydrocarbon streams by selectively oxidizing hard sulfurs in a hydrotreated stream are oxidized into the corresponding sulfoxides and sulfones, under oxidizing conditions in the presence of an effective amount of an oxidizing agent, wherein the oxidizing agent is a peroxometal complex and wherein the hard sulfurs. The said oxidizing agent is a peroxometal complex selected from the group consisting of one of the following forms: LMO (02) 2, (LL') MO(02)2, LMO(02).2.H2 0, and mixtures thereof, wherein M is selected from the group consisting of Mo, W, Cr and mixtures thereof and wherein L and Lr are neutral legends and wherein said sterically hindered sulfurs are converted into oxidation products. US Patent 6,071,738 relates to a method for the desulfurization of a fossil fuel containing one or more organosulfur compounds. This method comprises the steps of (1) contacting the fossil fuel with a biocatalyst capable of converting the organosulfur compound to an oxyorganosulfur compound which is separable from the fossil fuel; and (2) separating the oxyorganosulfur compound from the fossil fuel. Biocatalytic enzyme preparations that are useful in the present invention include microbial lysates, extracts, fractions, subfractions, or purified products obtained by conventional means and capable of carrying out the desired biocatalytic function. Generally, such enzyme preparations are substantially free of intact microbial cells, i.e., the enzyme preparations are cell-free fractions. The US patent 6,156,946 discloses a process for transforming aromatic organic compounds and resource materials. The process includes the steps of contacting an organic material selected from the group consisting of single and/or multi-ring aromatic compounds and alkylaromatic compounds, and their heteroatom-containing analogues, crude oil, petroleum, petrochemical streams, coals, shales, coal liquids, shale oils, heavy oils and bitumens with a microorganism or enzymes in order to hydroxylate the organic material, followed by contacting the hydroxylated organic resource material so as to cause hydrogenation and/or hydrogenolysis on the material. United States Patent 6,160,193 describes a two-step process for the removal of sulfur and nitrogen containing compounds from petroleum distillates. The first step of the process is to oxidize the sulfur-containing compounds of the fuel. The oxidization process converts sulfur compounds to highly polar sulfones. Nitrogen compounds are likewise converted to polar oxidized species. An example of an oxidizing agent that can be successfully used in this process is peroxysulfuric acid, often called Caro's acid. Oxidations are typically carried out at about 30 to 100 C, and preferably at 60 to 95°C. Low pressures are used, typically less than about 150 psig (pounds per square inch, gauge), and preferably less than about 30 psig, the autogenous pressures created by the vapors of the fuel and the various reactants and solvents. Sulfur- and nitrogen-containing compounds are oxidized using a selective oxidant to create compounds that can be preferentially extracted from a petroleum distillate due to their increased relative polarity. The second step of the process uses a solvent to extract the sulfones from the fuel oil. The United States Patent 6,638,419 relates to a method for obtaining oil products such as diesel fueJ with improved quality, from a gas oil fraction containing organosulphur compounds such as dibenzenethiophenes and/or their derivatives. The method includes at least two steps which consist in: (a) liquid-liquid extraction wherein the diesel fuel fraction is contacted with a solvent chosen form the group consisting of methanol, acetonitrile, monomethyl formamide, dimethyl formamide, dimethyl acetamide, N-methyl pyrrolidone, dimethyl sulfoxide and furfural,so as to obtain a gas oil-type raffinate with low content of sulphur and aromatic compounds and an extract rich in solvent and with high content of sulphur and aromatic compounds; (b) oxidation of the extract sulphur compounds by biological or chemical route , so as to obtain, after separation, a heavy gas oil-type hydrocarbon effluent with low sulphur content, and a residue comprising oxidized organosulphur compounds. Ayala et al. 1998 (Ayala MJinoco R,Hernandez V,Bremauntz P,Vazquez-Duhalt (1998) Biocatalytic oxidation of fuel as an alternative to biodesulfurization .Fuel Processing Technology 57:101-111.) has described a bioxidative method for fuel desulfurization using enzyme chloroperoxidase from Caldariomyces fumago. The method includes the steps of biocatalytic oxidation . of organosulfides and thiophenes, contained in the fuel, with hemoproteins to form sulfoxides and sulfones, followed by a distillation step in which these oxidized compounds are removed from the fuel. In this process straight-run diesel fuel containing 1.6% sulfur was biocatalytically oxidized with chloroperoxidase from Caldariomyces fumago in the presence of 0.25 mM hydrogen peroxide. The reaction was carried out at room temperature and the organosulfur compounds were effectively transformed to their respective sulfoxides and sulfones which were then removed by distillation. The resulting fraction after distillation contained only 0.27% sulfur. They have proposed biocatalytic oxidation of fuels as an interesting alternative to whole cell biodesulfurization. Wu et al. (2002) ( Q. Wu, M. R. Gray, M.A. Pickard, P.M. Fedorak, J.M. Foght 2002 Petroleum Chemistry Division Preprints 47(1) 615061) described biocatalytic ring opening of heterocycles dissolved in crude oil using bacterium Pseudomonas fluoresencens strain LP6a. The US patent 7,198,71 relates to a process desulfurization and, if necessary, for denitrification of hydrocarbon fractions the hydrocarbon mixture is brought into contact with a non-aqueous ionic liquid of general formula Q.sup.+A.sup.-, wherein Q.sup.+ is a ammonium, phosphonium or sulfonium cation, that contains at least one alkylating agent of the formula RX.sup.-, making it possible to form ionic sulfur-containing derivatives (and, if necessary, nitrogen-containing derivatives) that have a preferred solubility in the ionic liquid; and the ionic liquid is separated from the hydrocarbon mixture that is low in sulfur and nitrogen by decanting. The US patent 7,101,410 relates to a microbiological method of desulfurization (MDS) of hydrocarbon fuels such as coal, coal tar and petroleum uses an aqueous microbial biocatalytic agent which is not significantly reproducing but is still capable of oxidizing inorganic sulfur compounds and/or of selectively cleaving sulfur-carbon bonds in organic compounds, thereby removing sulfur with insignificant losses in fuel value. Microorganisms are selected according to the type of fuel sulfur present and the environment in which the desulfurizing process is to take place. One embodiment allows droplets of highly concentrated cell-water suspensions to pass from the top surface of the fuel through to the bottom, desulfurizing along the way and removing the sulfur products of the process as well. This MDS method can be used during hydrocarbon fuel production, storage, transport, and/or processing conditions, thereby also providing an added benefit in corrosion protection of the vessels used for these functions. The US patent 6,955,753 relates to a process and apparatus to extract and recover heavy metals and sulfur from crude oil or petroleum fuel products including the steps of emulsifying the crude oil with an emulsifying agent, adding a leach solution to the emulsified crude oil and leaching the emulsified crude oil at elevated temperature and pressure to give a leached emulsified crude oil. The leach solution may be acid or alkali. A proportion of the leach solution is extracted for recovering heavy metals. There can also be a microwave hydro-treating step using hydrogen gas at a temperature below 220.degree. C. to ensure there is no quality degradation in the crude feed to produce a desulftirized crude oil and a hydrogen sulphide by-product and recovering sulfur from the hydrogen sulphide by-product. The US patent 6,461,859 relates to a method of removing thiophenic and organosulfide compounds from a fossil fuel comprising the steps of contacting the fossil fuel with hemoproteins, which oxidize the sulfur containing compounds to sulfoxides and sulfones in a reaction system containing organic solvent or not, and followed by a distillation step in which sulfoxides and sulfones are removed from the fuel. Preferred biocatalysts include hemoproteins such as chloroperoxidase from Caldariomyces fumago, and peroxidases and cytochromes from animal, plant or microbial cells. The hemoprotein biocatalyst can be contacted with the fossil fuel in free or immobilized forms. The reaction can be carried out in the presence of the fuel alone or with addition of any organic solvent. The biocatalytically oxidized fuel is then distilled in order to eliminate the heavy fraction which contains most of oxidized organosulfur compounds. The light distillate contains significantly lower concentrations of sulfur when compared with the starting fossil fuel. The US patent 6,071,738 relates to a method for the desulfurization of a fossil fuel containing one or more organosulfur compounds. In one embodiment, the method comprises the steps of (1) contacting the fossil fuel with a biocatalyst capable of converting the organosulfur compound to an oxyorganosulfur compound which is separable from the fossil fuel; and (2) separating the oxyorganosulfur compound from the fossil fuel. The oxyorganosulfur compound can then be isolated, discarded or further processed, for example, via desulfurization by a biocatalyzed process or an abiotic process, such as hydrodesulfurization. The US patent 6,943,006 relates to a method for selective cleavage of C--N bonds genes that encode for at least one enzyme suitable for conversion of carbazole to 2-aminobiphenyl-2,3-diol are combined with a gene encoding an amidase suitable for selectively cleaving a C-N bond in 2-aminobiphenyl-2,3-dioI, forming an operon that encodes for cleavage of both C--N bonds of said carbazole. The operon is inserted into a host culture which, in turn, is contacted with the carbazole, resulting in selective cleavage of both C--N bonds of the carbazole. Also disclosed is a new microorganism that expresses a carbazole degradation trait constitutively and a method for degrading carbazole employing this microorganism. The US patent 6,124,130 relates to a method for removal of sulfur from fossil fuels containing sulfur by incubation of the fuel with microbes isolated and purified from soil or water that selectively extract the sulfur without apparently utilizing the fuel as a carbon or energy source. Preferred biodesulfurization microbes remove at least about 20% of the sulfur. The microbes are obtained in a multi-step screen that first selects microorganisms that utilize dibenzothiophene (DBT) as a sole source of sulfur, and then tests these in incubations with fossil fuels; organisms that desulfurize DBT without metabolizing the DBT phenyl ring structures and desulfurize fuels only when a second carbon source devoid of sulfur is present are identified and employed in desulfurization processes. Two cultures, CDT-4 and CDT-4b, were particularly efficacious in the desulfurization of liquid fossil fuels. The US patent 6071738 relates to a method for the desulfurization of a fossil fuel containing one or more organosulfur compounds. In one embodiment, the method comprises the steps of (1) contacting the fossil fuel with a biocatalyst capable of converting the organosulfur compound to an oxyorganosulfur compound which is separable from the fossil fuel; and (2) separating the oxyorganosulfur compound from the fossil fuel. The oxyorganosulfur compound can then bnitrogen compounds adding oxygen and reducing aromatic content by opening the ring oi- oxidizing. While a mixture of biocatalyst can be employed, to act on inorganic and organic sulfur with the modest utilization of carbon, the more preferred agents do not substantially affect the heating value of the fuel, but selectively oxidize organic sulfur and organonitrogen compounds which can either be physically removed by extraction with polar solvent. Any of the organisms effective for reacting with the sulfur content of bitumen can be employed. Specifically identified as useful are the following: Additionally, other microbiological biocatalyst which meet the objectives of the invention can be employed whether now known or which will be later developed. The reaction is conducted in any suitable reaction vessel by maintaining contact between the biocatalyst and the hydrocarbon for a time and under conditions effective to transform sulfur, organonitrogen and aromatic content of hydrocarbon. Contact of the bitumen with the biocatalyst is made at conditions effective for the reaction and will, like the supply of nutrients, pH adjustment, temperature, aeration, and the like, depend on the particular biocatalyst employed. The biochemical conditions of conversion according to this invention include : a tempreture from 9 degree C to 90 degree c, preferably in the range of from 30- 60 degree c; an air pressure less than or equal to 150 psi and peraferably from 15 psi-150 psi; a reaction time from 3 hours to 72 hours depending on the severity of the desired treatment and under aerobic conditions. The biocatalyst was used at the 5- 20% w/v, preferentially 10-15%. The biotreated oil was recvered by centrifugation or any other method of phase separation. The biocatalyst described in the present invention can be used to oxidize the aromatics and hetrocyclic aromatics in one stage or in mutilple stages. In multiple stages the treatment can be carried out in immediate succession, or with an interval of time between the stages of treatment. In the multistage treatment can be carried out applying same or different biocatalyst in all stages or their combinations. A significant advantage of the multistage treatment is that this result is accomplished by the removal of sulfur from a large and diverse array of the forms in which sulfur occurs in liquid fossil fuels utilizing substrate utilization of metabolic diviersty of biocatalyst. Thus, the stages of desulfurization treatment in the present invention combine synergistically to produce a deeply desulfurized fuel product. In the second stage and after separating biotreated fuel, it is subjected to liquid -liquid extraction. Solvents used for the extraction are typically polar organic materials with low solubility in the fuel and high affinity for the polar oxidized species. They should have low affinity for other compounds typically found in the fuels. Other important properties include high density to facilitate gravity separation. Extraction can be carried out at any combination of temperature and pressure where both the solvent and the treated hydrocarbon mixture are liquids. Solvent can be chosen from the group consisting of, but not rescricted to, water, N-methyl pyrrolidone, furfural, N,N-dimethylformamide, acetonitrile, methanol, dimethyl sulphoxide, with residence time of 2 to 60 minutes in the range of 5:1 to 50:1 preferably 10:1 to 30:1 at a temperature in the range of 20 to ■ '■ :\ . 80.degree. C followed by final finishing by passing through alumina, silica, clay or by adsorption on alumina, silica to obtain ultra low sulphur hydrocarbon fuels. The process described in present invention, herein do not degrades the organosulfur. organosulfiir or aromatics but transform them in oxidized and/or ring opened metabolites compounds which can be isolated and used or further processed, for example, via desulfurization by a biocatalyzed process or an abiotic process, such as hydrodesul fiirization. The presence of water is a fundamental factor for the operation of the invention, so that the oil was treated by adding the biocatlayst in the oil and MSM with glycerol mixxture. The micuorganisms aor their enzymes, included in this invention, are soluble in water. The oil: water as a working range of this invention is from 30: 70 to 70: 30. According to this invention, a biocatalyst is provided that is adopted for bioconversion of oil to convert them to upgraded oil. The biocatalyst that is claimed involves at least a bacteria or its enzymatic extracts, aconsortium of bacteria or their enzymatic extraxts, sleeted from the group Pseudomonas, Comomonas, and Bacilus. The biocalayst may also be used in the sequence i.e., the oil treated with one bacteria can be futher treated with another biocatlyst before or after of extraction. This sequencial treatemnt leads to further decrease in aromatics and hetrocycles. Preferred biocatalysts suitable for use herein selectively oxidize: sulfur-bearing heterocycles by addition of oxygen atoms to it, nitrogen-bearing heterocycles by addition of oxygen atoms to it and aromatics including monocyclic, dicyclic and polycyclic aromatics and/or ring opening of the same and accumulative the transformed compounds. The microorganisms can function as a biocatalyst in the present invention because each produces one or more enzymes (protein biocatalysts) that carry out the specific chemical reaction(s). Mutational or genetically engineered derivatives of any of the these microorganisms can also be used as the biocatalyst herein, provided that appropriate biocatalytic function is retained. Biocatalyst suitable for use as the biocatalyst in present process can be derived from naturally occuring microorganisms by known techniques. These methods involve culturing preparations of microorganisms obtained from natural sources such as sewage sludge, petroleum refinery wastewater, garden soil, or coal tar-contaminated soil under selective culture conditions; exposing the microbial preparation to chemical or physical mutagens; or a combination of these methods according the known art. Although living microorganisms (e.g., a culture) can be used as the biocataiyst herein, this is not required. In certain suitable microorganisms, including, the enzyme responsible for oxidation of organonitogen, organosulfur and aromatics is present on the exterior surface (the cell envelope) of the intact microorganism. Thus, non-viable (e.g., heat-killed) microorganisms can be used as a carrier for an enzyme biocataiyst. Other biocatalytic enzyme preparations that are useful in the present invention include microbial lysates, extracts, fractions, subfractions, or purified products obtained by conventional means and capable of carrying out the desired biocatalytic function. Generally, such enzyme preparations are substantially free of intact microbial cells. Enzyme biocataiyst preparations suitable for use herein can optionally be affixed to a solid support, e.g., a membrane, filter, polymeric resin, glass particles or beads, or ceramic particles or beads. The use of immobilized enzyme preparations facilitates the separation of the biocataiyst from the treated fossil fuel. In the process described in the present invention, the liquid fossil fiiel containing aromatics and heterocycles is combined with the biocataiyst preparation. The relative amounts of biocataiyst preparation and liquid fossil fuel can be adjusted to suit particular conditions, or to produce a particular level of residual sulfur, nitrogen and aromatics in the treated fossil fuel. The amount of biocataiyst preparation to be combined with a given quantity of liquid fossil fuel will reflect the nature, concentration and specific activity of the particular biocataiyst used, as well as the nature and relative abundance of inorganic and organic sulfur compounds present in the substrate fossil fuel and the degree of deep desulfurization/denitrogenation/dearomatization sought or considered acceptable. The concentration of a particular biocataiyst can be adjusted as desired for use in particular circumstances. The biocataiyst can be diluted with additional medium or another suitable buffer, or microbial cells present in the culture can be retrieved e.g., by centrifugation, and resuspended at a greater concentration than that of the original culture. The concentrations of non-viable microorganism and of enzyme biocataiyst preparations can be adjusted similarly. In this manner, appropriate volumes of biocatalyst preparations having predetermined specific activities and/or concentrations can be obtained. The volume and relative concentration of a given biocatalyst preparation needed for treatment is also related to the nature and identity of the substrate fossil fuel. Substrates that are very high in sulfur-bearing heterocycles, nitrogen bearing hetrocycles and aromatics or for which a very low level of residual sulfur is sought will require treatment by biocatalysts of high specific activity and/or high concentration. It is preferable to minimize the degree to which the substrate must be diluted with the biocatalyst; thus, smaller volumes of higher concentration and/or specific activity biocatalyst preparations are preferred. As a general rule, it is preferable that the biocatalyst preparation not exceed one-tenth of the volume of the combined biocatalyst and liquid fossil fuel during treatment. In some embodiments, the biocatajyst is added in substantially nonaqueous or solid form. For example, nonaqueous formulations of enzyme biocatalysts, or immobilized enzyme biocatalysts, can be used. Other conditions that affect the rate and extent of the treatment according to the present invention include the physical conditions to which the substrate fossil fuel/biocatalyst preparation mixture is exposed. The mixture can be incubated at any temperature between the pour point of the liquid fossil fuel and the temperature at which the biocatalytic agent is inactivated. Preferably, biocatalytic desulfurization is carried out at a temperature between about lO.degree. C. and about 60.degree. C. If desired, the mixture can be subjected to mechanical agitation to accelerate the rate of oxidation by ensuring thorough and even distribution of the biocatalyst preparation in the substrate. Suitable means for introducing mechanical agitation include, for example, incubation in a stirred-tank reactor. Alternatively, the substrate fossil fuel can be caused to flow through or over a filter, membrane or other solid support to which an immobilized biocatalyst preparation is affixed. The mixture of biocatalyst and substrate fossil fuel can be incubated for a predetermined period of time, a sufficient period of time for the desired level of oxidation to be attained. Following treatment, the biocatalyst is separated from the treated fossil fuel using known techniques such as decanting, water extraction or fractional distillation. Immobilized biocatalysts are particularly well-suited for separation from the treated fossil fuel. Enzyme biocatalysts immobilized on a resin or on beads can be recovered by centriligation, and enzymes affixed to membranes or filters can be recovered, e.g., by filtering the treated fossil fuel therethrough. The conditions of the bioconversion are more advantageous compared with the convential conversion with hydrogen, becasuse lower pressure than those required to maintain the hydrogenation can be used. Thus, the process of biochemical conversion of this invention permits the reduction of costs of equipment and operating costs, derived from conditions at high tempretures, producing at the same time a reduction in aromatic contnt, sulfur content and nitrogen content and its clarofic value are maintained. The extracted polar componds may be subjected to hydrogenation or may be used as substarte for manufacturing of value added product. A feature of the invention is that dearomatization, desulphurization and denitrogenation occur in a single step. This invention is futher illustrated by the following examples, which are not to be construed in any way as imposing, limitatuion upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other embodimnets, modifications, and equivalents therof which after reading the description herein, may suggest themselves to those skilled in the art without departing from the spirit of the present invention and /or the scope of the appended claims. Examplel: Upgrading of the light cycle oil Isolation of PAH degrading bacteria: The nutrient media (basal salt media, BSM) used for enrichment process includes (gl"1) 6.0 g of Na2HP04,3.0 g of KH2P04, 4.0 g of NH4Cl, 2.5 g yeast extract, 0.1 g of MgS04 and 2.5 ml of a trace element solution ([mgl"1], 23 mg of MnCl2 • 2H20, 30 mg of MnCL, ■ H20, 31 mg of H3B03j 36 mg of CoCl2 ■ 6H20, 10 mg of CuCl2 • 2H20, 20 mg of NiCl2 • 6H20, 30 mg of Na2Mo04 ■ 2H20, and 50 mg ZnCl2) (pH 7.0). Highly aromatic waste (2%, wv" ) was used as carbon source and incubated at 30°C on a rotary shaker (200 rpm) for 4 days. After four days 1ml of the culture was transferred to fresh media containing crude oil (2%, wv"1) and re-incubated for another four days. Following five cycles of such enrichment, 1 ml of the culture was diluted and plated on BSM agar plates containing crude oil as sole carbon source. The bacterial colonies obtained were further purified by streaking on Luria-Bertani agar. The ability of the isolates to various PAHs and highly aromatic was determined by growing it, separately, in BSM containing one of the test hydrocarbon as sole carbon source. The fastest growing strain P. putida IOC5al with ability to grow on wide range of hydrocarbon was selected for further studied for Quantitative degradation of representative PAHs. These bacterial strains were identified by 16S r RNA partial gene sequencing and biochemical assays. Development of biocatalyst: The strain P. putida IOC5al was modified by transposon mediated Tn5 mutagenesis. E. coli C600(pGS9::Tn5) (REF) and P. putida IOC5al were grown to an ODeoo of 0.8. Transconjugants were selected on plates containing kanamycin (50 ul/ml). Colonies were picked and replica plated on BSM_Agar DBT plate to screen the mutants capable of accumulating ring-opening metabolites. This assay is based on ability of mutants to utilize various intermediate compounds of dioxygenase and salicylate pathway in agar plate. The ability of mutants to accumulate ring opened metabilites was studied using dibenzothiophene as substrate because ( in contrast to other PAH) its ring cleavage products are highly colored giving a rapid visual indication of substrate transformation. The product formed by mutants were confirmed by UV-spectrascopy, IR, and NMR. To treat mutant was grown overnight in nutrient broth and harvested by cenrrifugation at 8000 rpm. This pallet was used as biocatalyst. To normalize the dosing dry weight of a part of the pallet was taken by the conventional oven drying. LCO treatment: The LCO upgrading was carried out in 7 lit bioreactor containing 2.5 lit of LCO ( Total aromatics : 70% , Total sulfur : 2.6%, Total Notrogen: 240 ppm) and 1.5 lit of BSM media containing glycerol ( 6%) as carbon source. The dosing rate of pre-grown biocatalyst was 20 g (dry weight). The bioreactor running conditions were: Stirrer speed: 700,pH 7.0,Air: 2Litre/min. After 10 hours the cells, oil and water was separated by centrifugation at 8000 rpm, 5 min. A control without biocatalyst was run under similar experimental conditions. The treated oil was extracted with equal volume of Furfural by mixing it with solvent under stirring conditions at 60. °C for 2 hr. After extraction the oil was analyzed for aromatic content, sulfur content and nitrogen content by NMR, GC-SCD and NS analyzer (ASTM 4629) methods, respectively. Table: 1 Upgrading of light cycle oil Sample Sulfur Nitrogen Total Content content (ppm) Aromatic (%) content ( %) Untreated 2.6 240 78 Treated 0.2 075 35 and extracted Untreated 2.0 200 65 extracted Example 2: Upgrading of LGO The LGO was treated with the biocatalyst described above under similar experimental contions.Resuhs are as follows: Table: 2 Upgrading of LGO Sample Sulfur Nitrogen Total Content content (ppm) Aromatic (%) content ( %) Untreated 1.7 190 69 Treated 0.3 060 32 and extracted Untreated 1.4 200 58 extracted