The present invention relates to an improved process for microbial dephosphorisation of LD slag for utilisation in steel making. This invention particularly relates to the optimization of process parameters and use of novel microbial isolates. The microbial isolates screened from LD slag dump site were found to be able to degrade calcium silicate and calcium phosphate matrix. These isolates on sequential adaptation to various concentrations of calcium phosphate improved their efficiency of phosphorus removal. The novelty of the present invention is the single step approach with a new isolate of Burkholderia species, with high resistance to calcium silicate/ phosphate to selectively degrade and solubilise phosphorus in solution. The dissolution of phosphorus from LD Slag in aqueous medium occurs at room temperature, atmospheric pressure without media resulting nearly 99% phosphorus removal in 5 days. The process is of low cost and the large scale can be used industrially. The process meets the strict environmental regulations of making LD slag suitable for steel making applications. LD slag is an unutilised product from the refining of pig iron in the LD converter process. The LD slag has been analysed to be a suitable replacement to additional requirement of CaCO3 due to high content of CaO rendering it the value of ideal flux for charging in blast furnace. The recycling of LD slag is quite minimal due to high levels of phosphorus which causes high phosphorus in steel degrading its properties. The presence of high phosphorus (against Industrial standards of <0.05%) makes it an unsuitable for industrial applications. In this age of competitiveness to minimize production cost, a good step can be taken to reuse LD-slag in steelmaking and iron making process. It is necessary to reduce the phosphorus contamination to produce high quality steel products to avoid its adverse effect on mechanical properties due to segregation in grain boundaries during solidification and heat treatment. So after elimination of phosphorous, if possible, this LD-slag can be recycled as a flux material in steelmaking and also can be charged in blast furnace as an alternative of lime stone as well as its also avoids heat loss for calcination of limestone. LD slag finds considerable applications otherwise in road making, building materials, and fertilisers and also to recover vanadium. Therefore, many technologies are being adapted to reduce the phosphorus in LD slag in order to increase its applicability in steel and iron making. Some of the research works are discussed below. Physical and Chemical methods: Due to exploitation of primary or high grade mineral deposits, it has become increasingly important to process lower grade or complex ores, as well as industrial and mining wastes. Elements such as phosphorus (P) and potassium (K) contained in the low grade iron ore have a detrimental effect on steel making process, whereby these alkali’s cause cracks to form in the refractory lining of blast furnaces (Yusfin et al., 1999). The behavior of phosphorus in the solid state pre-reduction and dephosphorization treatment processes of high phosphorus iron ore by mechanical crushing and screening methods were investigated by Matinde et al.(2011). Phosphorus was vaporized as unstable PO and PO2 gas intermediates in the reduction process of high phosphorus iron ore. However, the extent of phosphorus vaporization was not significant enough to consider as a dephosphorization treatment at process levels. Most of the phosphorus compounds were not reduced in the solid state carbothermic reduction process of high phosphorus iron ore and remained as oxides in the gangues. The gangue phase increased from 5 to 20–30mm after pre-reduction thereby providing the motivation to separate of the phosphorus-rich gangue from the pre-reduced iron ore by mechanical crushing and screening methods. The degree of sintering of the reduced phases was observed to be a critical parameter in the dephosphorisation treatment of high phosphorus iron ore by these methods. A study on the dephosphorization of Agbaja iron ore using hydrometallurgical process has been carried out by Chime et al. (2012). The central composite design of 23 response was formulated and used to develop a model equation. The optimized result of the equation using Matlab shows that 97.97% degree of dephosphorization was obtained at 117 minutes leaching time, 0.2M HCl and particle size of 30 microns. Iron loss during the hydrometallurgical leaching was less than 5%. A process for the dephosphorization of iron ore was proposed by Muhammed and Zhang (1989) which consists of an integrated treatment by leaching and further processing of the leach solution. Phosphoric acid is extracted by isoamyl alcohol (iAmOH) and stripped by nitric acid solution. Phosphoric acid is concentrated by evaporation where most of the nitric acid is removed. The remaining nitric acid is extracted by methyl isobutyl ketone. The raffinate from the phosphoric acid extraction is treated by sulfuric acid for the regeneration of the spent nitric acid. Nitric acid is extracted by iAmOH and concentrated by distillation before re-used in further leaching. Dephosphorisation of western Australian iron ore by hydrometallurgical process has been demonstrated by Cheng et al. (1999). Sulphuric acid was chosen as the leachant on the basis of its availability and low cost. The iron ore sample used in this study typically contained 0.126% phosphorus, was from the Pilbara region of Western Australia. After roasting at 1250°C, lump ore (P80 5.6 mm), pellet 1 (grinding to 100% -1.5 mm before pelletisation) and pellet 2 (grinding to 100% -0.15 mm before pelletisation) were leached in solutions with different sulphuric acid concentrations. After leaching for 5 hours at 60°C in 0.1 M sulphuric acid solution, 67.2%, 69.0% and 68.7% of the phosphorus was leached from the above three samples, respectively. The phosphorus content was reduced from 0.126% to 0.044%, 0.055% and 0.042% respectively. The dissolution of iron during leaching was negligible. The optimum sulphuric acid concentration was 0.1 M in terms of acid cost and iron loss. The dephosphorization of high phosphorus iron ores by pre-reduction, air jet milling and screening methods was investigated by Matinde and Hino, 2011. They reported that at a fixed milling gas kinetic energy, the milling and the pre-reduced iron ore gangue separation behaviour was highly dependent on the solids feed rate. The degree of sintering and agglomeration of the reduced iron grains was critical in controlling the dephosphorization treatment process of the pre-reduced iron ore by air jet milling and fine screening methods. The dephosphorization process proposed in this work involves a pre-reduction process by carbonaceous materials at 1200°C for 0.5 h, air jet milling using gas kinetic energy of 325.24kJ and specific energy consumption of 3.24 kJkg–1h, and screen separation using a 25 μm sieve. Nwoye et al. (2009) studied the optimum dissolution temperatures of phosphorus in oxalic, nitric and sulphuric acid solutions during leaching of iron oxide ore. Phosphorus dissolution rates and dissolution per unit rise in temperature were determined and compared to ascertain the preferred acid in terms of effective dephosphorization of iron oxide ore using leaching process. The results of the investigation show that the optimum dissolution temperatures of phosphorus in these acids were found to be 45, 55 and 70oC respectively. Phosphorus dissolutions per unit rise in temperature in these acid solutions during the increasing and decreasing stage of dissolution were 9.4 and -3.07 mg/kg/oC 2.88 and -4.7 mg/kg/oC and also 2.16 and -7.95 mg/kg/oC respectively. Phosphorus dissolution rates in these acid solutions during the increasing and decreasing stage of dissolution were also determined as 0.67 and -0.13 mg/kg/s, 0.14 and -0.19 mg/kg/s and also 0.1 and 0.44 mg/kg/s for oxalic, nitric and sulphuric acid solutions respectively. This confers to oxalic acid a better dissolution power on phosphorus over nitric and sulphuric acid, followed by nitric acid. Phosphorus removal from goethitic iron ore with a low temperature heat treatment and a caustic leach was investigated by Fisher-white et al. (2012). Phosphorus associated with the goethite in high-phosphorus iron ores can be removed to 0.075% P using a heat treatment at 300-350°C for 1 h with 10 wt% NaOH, followed by a water leach. Heating at higher temperatures, up to 500°C, with heating times of 0.5 h to 4 h, gave no improvement in phosphorus removal. Similar phosphorus removal was achieved by heating the ore at 300-350°C for more than 0.5 h and leaching with 1-5 M NaOH at the boiling point for 3 h. The concentration of sodium hydroxide required depended on the amount of phosphorus to be removed. Heating for up to 2 h or at higher temperatures up to 750°C did not improve the amount of phosphorus removed in the caustic leach. The temperature of the leach had a significant effect on the amount of phosphorus removed with less phosphorus being removed below the boiling point of the leach liquor. The heat treatment at 300–350°C is considered to dehydroxylate the goethite to form a hematite intermediate phase, ‘protohematite’, from which the phosphorus is dissolved during the leach step. Phosphorus removal of high phosphorus iron ore by gas-based reduction and melt separation was studied by Tang et al., 2010. The gas-based reduction was carried out using a fixed bed reactor and the ore sample of 80 g with an average particle size of 2 mm were reduced using CO or H2 at temperature of 1073 K for 5 hours. 50 g of the reduced sample with 3.0% CaO as additive was then subjected to melt separation in an electric furnace at temperature of 1873 K under Ar atmosphere. In each run, SEM, EDS, optical microscopic examination and chemical analysis of the reduced ore sample, the metal sample and the slag sample were conducted. Results of all gas-based reduction experiments showed that iron metallization ratios were some 65% and the phosphorus compounds in the ore remained unchanged. It was agreed well with the simulations except for the iron metallization rate being less than predicted value; this difference was attributed to kinetics. Results of melt separation experiments showed that P content in metal samples is 0. 33% (metal sample from H2 reduction product) and 0.27% (metal sample from CO reduction product). The phosphorus partition ratios of both cases were less than predicted values. Some P in the metal samples existed as slag inclusion was considered to be the reason for this discrepancy. The selective HCI leaching method was used to remove phosphorus from high phosphorus iron ores (Xia et al., 2011). The hydroxyl-apatite in high phosphorus iron ores was converted into soluble phosphate during the process of HCl leaching. The effects of reaction time, particle size, hydrochloric acid concentration, reaction temperature, liquid-solid ratio and stirring strength on the dephosphorization ratio were studied. The results showed that the dephosphorisation ratio can exceed 98% under the conditions of reaction time 30-45 min, particle size 98%. 3. A process as claimed in claim 1, wherein the LD slag pulp density is >50%. 4. A process as claimed in claim 1, wherein the LD slag having particle size of <6mm is used. 5. A process as claimed in claim 1, wherein 10% bacterial inoculum contains 2x10' cells/mL. 6. A process as claimed in claim 1, wherein the effluent pH was 6-6.5 and contain cells for reuse. 7. A process for the microbial removal of phosphorus substantially as herein described with reference to the foregoing examples.