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Abstrak :
Kegiatan industri migas sangat potensial menyebabkan pencemaran air, tanah, dan udara. Minyak yang merembes ke dalam tanah dapat menyebabkan tertutupnya suplai oksigen dan meracuni mikroorganisme tanah sehingga mengakibatkan kematian mikroorganisme tersebut. Tumpahan minyak di lingkungan dapat mencemari perairan dan tanah hingga ke daerah sub-surface dan lapisan aquifer air tanah. Bioremediasi memainkan peranan penting yang makin meningkat pada remediasi lingkungan tercemar polutan organik dan telah diterima secara luas sebagai teknologi inovatif. Bioremediasi adalah suatu teknologi aplikasi proses biologis untuk melenyapkan bahan kimia beracun dan berbahaya dari lingkungan dengan melibatkan agen biologis seperti tanaman, mikroorganisme, dan enzim tanaman/mikroorganisme. Untuk mengatasi pencemaran limbah minyak, maka diperlukan suatu cara penanggulangan yang efisien, efektif, ekonomis, dan tidak merusak lingkungan. Penelitian ini akan menguji sejauhmana keefektifan pemanfaatan bakteri pemecah minyak dalam proses bioremediasi. Dengan demikian, diharapkan dapat diperoleh jenis bakteri yang dapat mendegradasi minyak bumi secara cepat sehingga tidak lagi berperan sebagai pencemar di lingkungan. Tujuan penelitian ini adalah: (a) memperoleh jenis bakteri pemecah minyak yang mampu mendegradasi senyawa hidrokarbon dalam proses bioremediasi; (b) mengetahui pengaruh jenis bakteri, pH, dan waktu degradasi terhadap pertumbuhan bakteri pemecah minyak dan proses bioremediasi; (c) membandingkan pertumbuhan bakteri pemecah minyak dalam mendegradasi tanah terkontaminasi minyak dan tanah tidak terkontaminasi minyak; (d) mengetahui kondisi lingkungan yang optimum bagi pertumbuhan bakteri; dan (e) mengetahui alternatif penanggulangan pencemaran minyak bumi dalam upaya pengelolaan lingkungan. Berdasarkan hasil penelitian ini diharapkan dapat diperoleh: (a) informasi dasar tentang pemanfaatan bakteri pemecah minyak dalam proses bioremediasi sehingga akan menjadi pertimbangan bagi penelitian selanjutnya; (b) bakteri pemecah minyak dalam penelitian ini diharapkan dapat diaplikasikan di lapangan dalam proses bioremediasi; dan (c) upaya pengelolaan lingkungan yang tepat untuk mengatasi pencemaran limbah minyak. Hipotesis yang diajukan adalah: (a) jenis bakteri, pH, dan waktu degradasi berpengaruh terhadap pertumbuhan bakteri pemecah minyak dan proses bioremediasi; (b) kondisi tanah terkontaminasi minyak dapat meningkatkan pertumbuhan bakteri pemecah minyak daripada tanah tidak terkontaminasi minyak. Penelitian dilakukan dengan metode eksperimen, dimana sampel tanah terkontaminasi minyak dan tanah tidak terkontaminasi minyak diperoleh dari lokasi 9C-68, Minas SBU, PT. CPI, Riau. Sampel bakteri Pseudomonas fluorecence dan Bacillus subtilis diperoleh dari Laboratorium Pangan dan Gizi, Institut Pertanian Bogor. Waktu penelitian dilaksanakan pada bulan April-September 2001. Analisis kandungan minyak total (TPH) dan kromatogram dilakukan di Environmental and Technology Support Laboratory, PT. CPI, Duri. Analisis kualitas tanah (tekstur tanah, N, P, dan K), kualitas air (pH, DO, CO2, BOD5, dan COD), dan mikrobiologi dilakukan di Laboratorium Mikrobiologi Pangan, Fakultas Perikanan dan Ilmu Kelautan UNRI. Data dalam penelitian ini terdiri atas data primer dan data sekunder. Data primer diperoleh dari pengukuran secara langsung di Laboratorium. Data sekunder diperoleh dari instansi terkait, studi pustaka, dan sebagainya. Data primer dan data sekunder ini kemudian dianalisis secara deskriptif yaitu dilakukan uji statistik ANAVA untuk menguji keberartian variabel pada perlakuan. Isolat bakteri Pseudomonas fluorescence, Bacillus subitilis, dan kultur campuran (Pseudornonas fluorescence T Bacillus subtilis) dapat digunakan dalam proses bioremediasi. Namun, bakteri Pseudomonas fluorescence pada pH 8 lebih cepat mendegradasi senyawa hidrokarbon pada tanah terkontaminasi minyak dengan laju biodegradasi sebesar 96,1 ppm/hari dan persentase penurunan sebesar 91,51%. Kultur campuran pada pH 7 merupakan isolat dengan aktivitas metabolisme yang lebih tinggi dilihat dari total bakteri pemecah minyak, baik pada tanah terkontaminasi minyak maupun tanah tidak terkontaminasi minyak. Berdasarkan hasil kerjanya, kedua bakteri ini bersifat sinergisme. Perlakuan kontrol (B0) mempunyai pH lebih rendah dibandingkan perlakuan lainnya, baik pada tanah terkontaminasi minyak maupun tanah tidak terkontaminasi minyak. Kegiatan bakteri pemecah minyak dalam mendegradasi senyawa hidrokarbon menyebabkan penurunan pH. Waktu degradasi berpengaruh terhadap total bakteri, dimana semakin lama waktu degradasi, maka semakin tinggi total bakteri sampai batas tertentu sebelum terjadi fase kematian. Waktu degradasi juga berpengaruh terhadap persentase degradasi senyawa hidrokarbon, dimana kandungan TPH yang terendah terdapat pada minggu II (T2). Proses bioremediasi ini telah berlangsung dengan baik karena kandungan TPH telah mencapai 1% atau kurang dari 10.000 ppm. Pada tanah terkontaminasi minyak terdapat total bakteri pemecah minyak yang lebih tinggi dibandingkan tanah tidak terkontaminasi minyak. Bakteri pemecah minyak memanfaatkan senyawa hidrokarbon sebagai sumber energi dan sumber karbon sehingga meningkatkan pertumbuhan bakteri tersebut. Untuk penelitian selanjutnya, maka perlu dilakukan penelitian proses bioremediasi di lapangan yang terkontaminasi minyak. Penelitian juga perlu dilakukan mengenai jenis bakteri pemecah minyak lainnya yang mampu mendegradasi hidrokarbon dalam limbah minyak sehingga dapat dilakukan proses pembiakan dan pembuatan isolat untuk tujuan komersial. Untuk mendapatkan gambaran yang menyeluruh mengenai proses bioremediasi, maka perlu diteliti faktor-faktor lain yang belum diamati dalam penelitian ini seperti kandungan bahan organik, anorganik, dan unsur hara tanah. Upaya pengelolaan limbah dapat dilakukan dengan konsep minimisasi limbah baik secara langsung maupun tidak langsung. Namun, tindakan pencegahan lebih berharga daripada penanggulangan terhadap terjadinya pencemaran limbah minyak di lingkungan. Pengelolaan lingkungan dapat terlaksana dengan baik apabila didukung oleh kesadaran dan peran serta masyarakat. Disamping itu, perlu dilengkapi dengan peraturan hukum yang berlaku.

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The Utilization of Hydrocarbon Degradation Bacteria in Bioremediation Process (A Case Study in Processing of Contaminated Ground Oil in Minas SBU, PT. Caltex Pasific Indonesia, Riau)Migas industry activity is very potential to cause water, ground, and air pollution. The infiltration of oil into ground layer will cover the oxygen supply, poison and kill the ground microorganism. Oil spilled into environment also pollute the aquatic environment, sub surface area of ground and aquifer layer of ground water. Bioremediation plays an important role in remediation of polluted environment by organic pollutant and has been widely accepted as an innovative technology. Bioremediation is an applied biological process technology to disappear poison and dangerous substances from the environment with involves biological agents such as plant, microbial and plant/microbial enzymes. To overcoming of earth oil pollution, an efficient, effective, economics, and not damage environment method is needed. This research will test how the effective the utilization of hydrocarbon degradation bacteria in bioremediation process. So hopefully it can find type of bacteria that able to degrade hydrocarbon compound so quickly until it can not participate as a polluter in environment. The objectives of this research were: (a) to find type of hydrocarbon degradation bacteria that able to degrade hydrocarbon compound in bioremediation process; (b) to know the influence of bacteria type, pH, and degradation time on the growth of hydrocarbon degradation bacteria and bioremediation process; (c) to compare the growth of hydrocarbon degradation bacteria in degrading contaminated ground oil and uncontaminated ground oil; (d) to know the optimum environment condition for the bacteria growth; and (e) to know the alternatives to overcome earth oil spilled in environmental management efforts. Accordance with the results of this research expected: (a) to give information about the utilization of hydrocarbon degradation bacteria in bioremediation process for become the basic considerations of further research; (b) hydrocarbon degradation bacteria on this research could be applied into environment in bioremediation process; and (c) the efforts of approsiate environmental management to overcome waste oil pollution. Hypothesis of this research were: (a) type of bacteria, pH, and degradation time influence the growth of hydrocarbon degradation bacteria and bioremediation process; (b) contaminated ground oil condition could increase the growth of hydrocarbon degradation bacteria than uncontaminated ground oil. This research was done by used of experimental method. Samples of contaminated and uncontaminated ground oil were obtained from 9C-68 location, Oil area Minas SBU, PT. CPI, Riau. Samples Pseudomonas fluorescence and Bacillus subtilis were obtained from Food and Nutrient Laboratory, Bogor Agriculture Institute. The research was conducted on April-September 2001. Total Petroleum Hydrocarbon (TPH) and chromatography analysis were conducted at Environmental and Technology Support Laboratory, PT. CPI, Duri District. Analysis of ground quality (ground texture, IN, P, and K), water quality (pH, DO, COz, BOD5, and COD) and microbiology were conducted at Food Microbiology Laboratory, Faculty of Fishery and Marine Science, University of Riau. Data in this research were consisting of primary and secondary data. Primary data was obtained by directly measurement in laboratory. Secondary data was obtained by literature study, in interrelated office, and so on. These two types of data were analyzed descriptively with ANAVA statistical test to examine the variable significance in every treatment. Isolated of Pseudoinonas fluorescence, Bacillus subtilis, and mixture culture of (Pseudomonas fluorescence Bacillus subtilis) can be used in bioremediation process. But, Pseudomonas fluorescence bacteria at pH 8 can accelerate to degrade hydrocarbon compound in contaminated ground oil with biodegradation rate of 96,1 pprnlday and decreasing percentage rate of 91,51%. Mixture culture bacteria at pH 7 are isolate with higher metabolism activity viewed by total of hydrocarbon degradation bacteria, both in contaminated ground oil and in uncontaminated ground oil. According to its activity production, both bacteria have synergism characteristic. Control treatment (BO) has pH value lower than the other treatment, both in contaminated ground oil and uncontaminated ground oil. The activity of hydrocarbon degradation bacteria to degrade hydrocarbon compound has decreased pH value. Degradation time influenced bacteria total where longer of degradation time will increase the bacteria total until in fixed level before lethal phase occurs. Degradation time also influenced hydrocarbon compound degradation percentage where the lowest of TPH content found at second week (T2). This bioremediation process occurred well because the TPH content has reached of 1% or less than 10.000 ppm. In contaminated ground oil has higher total of hydrocarbon degradation bacteria than in uncontaminated ground oil. Hydrocarbon degradation bacteria used hydrocarbon compound as energy source and carbon source until increase that bacteria growth. For the next research, it is necessary to search the bioremediation at polluted field of oil waste. Research is also necessary doing to the other types of hydrocarbon degradation bacteria that able to degrade hydrocarbon in oil waste so breeding process and isolate making could be done for commercial perspectives. To find entirely description of bioremediation process, it is necessary to search the other factors that still not observed and measured in this research such as organic, inorganic substance content, and ground nutrients. Efforts of waste management can be done with waste minimization concept either directly or indirectly manners. But, prevention action is more valuable than to overcome oil waste pollution in environment. Environmental management will be well implemented if it is supported by awareness and participation of community. In addition, it should be provided by law regulations.

Abstrak :
Kegiatan industri pertambangan minyak bumi di Indonesia telah menimbulkan banyak kasus pencemaran limbah berbahaya dan beracun (B3). Kasus tersebut dapat menimbulkan dampak buruk bagi kualitas lingkungan. Pada KepMenLH No. 128 Tahun 2003, disebutkan bahwa pemulihan lahan tercemar oleh minyak bumi dapat dilakukan secara biologis, dengan menggunakan kapasitas kemampuan mikroorganisme. Salah satu teknik penerapan pemulihan tersebut adalah dengan menggunakan teknik Bioventing. Tujuan penelitian ini adalah untuk mengetahui pengaruh injeksi udara dan mikroorganisme yang berperan dalam proses remediasi dan faktor-faktor yang mempengaruhi kinerjanya bioventing. Minyak bumi yang digunakan merupakan crude oil yang berasal dari PPPTMGB Lemigas. Selama 5 minggu penelitian, didapatkan penyisihan konsentrasi TPH terbesar yaitu sebesar 82% yang terdapat pada sampel dengan konsentrasi bakteri Bacillus Subtilis 10% v/v. Sedangkan pada sampel dengan konsentrasi bakteri Bacillus Subtilis 15% v/v, dan tanpa penambahan bakteri (bakteri indigenous) 1 dan 2 secara berurut adalah 67,1%, 54,24%, dan 68,12%. Penyisihan konsentrasi BTEX terbesar, yaitu sebesar 66,65% pada kontrol 2. Sedangkan sampel dengan kontrol 1, konsentrasi bakteri Bacillus Subtilis 10% v/v, dan bakteri Bacillus Subtilis 15% v/v secara berurut adalah 23,39%, 34,41%, dan 37,69%. Dari penelitian ini dapat disimpulkan bahwa sampel dengan konsentrasi bakteri Bacillus Subtilis 10% v/v dan Kontrol 2 yang paling baik dalam mendukung efektivitas proses degradasi minyak bumi.

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Oil mining industry in Indonesia has generated many cases of very hazardous waste pollution. Those cases could adversely affect the quality of environment. Ministry of Environment through the Ministry of Environment Decree No. 128/2003, stated that the recovery of oil contaminated area can be purified by using microbial activity, called bioremediation. On of the most preferred methods for the remediation process of oil contaminated soil is bioventing. The main objective of this study was to determine the effect of air injection and microorganisms that play a role in the remediation process and the factors that affect performance bioventing. Oil used in this study was crude oil which was derived from PPTMGB Lemigas. The purpose of this study. During the 5 weeks of the study, obtained the largest TPH concentrations allowance that is equal to 82% were found in the sample with the concentration of the bacteria Bacillus Subtilis 10% v/v. While the sample with the concentration of bacteria Bacillus Subtilis 15% v/v, and without the addition of bacteria (indigenous) 1 and 2 in sequence is 67.1%, 54.24%, and 68.12%. Provision largest concentration of BTEX, amounting to 66.65% in the control 2. Whereas the control 1, the concentration of the bacteria Bacillus Subtilis 10% v / v, and the bacteria Bacillus Subtilis 15% v / v in the order are 23.39%, 34.41%, and 37.69%. From this study it can be concluded that the sample with the concentration of the bacteria Bacillus Subtilis 10% v / v and Control 2 is best in support of the effectiveness of oil degradation process.

Abstrak :
ABSTRAK
Kegiatan eksplorasi dan produksi minyak bumi berpotensi menimbulkan kontaminasi minyak pada tanah, misalnya dari kegiatan operasional, kebocoran pipa, maupun akumulasi timbulan limbah minyak di masa lalu. Keputusan Menteri Lingkungan Hidup no 128 tahun 2003 menyatakan bahwa tanah yang terkontaminasi minyak dikategorikan sebagai limbah bahan berbahaya dan beracun (B3) yang berpotensi menimbulkan kerusakan lingkungan. Pemulihan tanah tercemar oleh minyak bumi dapat dilakukan secara biologis, dengan menggunakan kapasitas kemampuan mikroorganisme. TPH atau Total Petroleum Hydrocarbons dalam hal ini merupakan jumlah hidrokarbon minyak bumi yang terukur dari media tanah. Dalam Keputusan Menteri Lingkungan Hidup No.128 tahun 2003 dijelaskan bahwa target konsentrasi TPH yang aman bagi lingkungan ialah dibawah 1%. Landfarming merupakan salah satu teknik yang dapat diterapkan dalam pemulihan tanah tercemar minyak bumi. Tujuan penelitian ini adalah untuk mengetahui jenis bulking agent yang paling efektif dalam pelaksanaan proses bioremediasi. Sampel tanah terkontaminasi minyak bumi yang diolah diambil dari tanah terkontaminasi minyak mentah (Crude Oil Contaminated Soil) di Pre-treatment pit dalam (SBF) Soil Bioremediation Facility PT. Chevron Pacific Indonesia di Minas, Riau. Bulking agent yang digunakan dalam penelitian adalah serbuk kayu dan cacahan serabut tandan kosong kelapa sawit. Selama 6 minggu penelitian, penyisihan konsentrasi TPH terbesar yaitu 41,04% pada sampel dengan penambahan bulking agent serbuk kayu 4% (w/w). Sedangkan pada sampel dengan penambahan bulking agent serabut tandan kosong kelapa sawit 4% (w/w) dan tanpa penambahan bulking agent berturut-turut adalah 40,45% dan 35,04%. Dari penelitian ini dapat disimpulkan bahwa sampel dengan penambahan bulking agent serbuk kayu 4% (w/w) yang paling efektif dalam proses degradasi minyak bumi.

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ABSTRACT
Exploration and production of oil has potential to contaminate soil, such as from operations, pipeline leak, and accumulation of oil waste. Ministry of Environment through the Ministry of Environment Decree No. 128/2003, stated that oil contaminated soil is classified as hazardous and toxic waste (B3) that could potentially cause damage to the environment. The remediation of oil contaminated soil can be purified by using microbial activity. TPH or Total Petroleum Hydrocarbons is the amount of petroleum hydrocarbons measured from the soil media. In MOE Decree No. 128/2003 stated that TPH concentrations target that are safe for the environment is below 1%. Landfarming is one of the most preferred technique that can be applied in the remediation of oil contaminated soil. The main purpose of this study was to determine which type of bulking agent is the most effective on bioremediation process. Crude Oil Contaminated Soil sample were taken from pre-treatment pit in Soil Bioremediation Facility PT. Chevron Pacific Indonesia in Minas, Riau. Bulking agents used in the study were wood chip and oil palm shell fiber. During 6 weeks of the study, the largest TPH removal was 41.04% which is a sample with the addition of 4% wood chip (w/w). While the sample with the addition of 4% oil palm shell fiber (w/w) and the sample without the addition of bulking agent were respectively 40.45% and 35.04%. From this study, it can be concluded that the sample with the addition of 4% wood chip (w/w) was the most effective in the crude oil biodegradation process.

Abstrak :
Teknologi Bioremediasi merupakan teknologi yang belakangan ini digunakan sebagai cara alternatif penanggulangan limbah hidrokarbon . Metode ini menggunakan mikroorganisme bakteri pemecah minyak seperti Pseudomonas aeruginosa untuk mendegradasi senyawa hidrokarbon sehingga dapat memulihkan lingkungan, tanah dan air yang tercemar. Penelitian pengujian ketahanan dan bakteri Pseudomonas aeruginosa ini merupakan bagian dari penelitian Tim Bioremediasi yang dilakukan di Departemen Teknik Gas dan Petrokimia. Penelitian ini dilakukan dengan menggunakan limbah buatan, yang merupakan campuran isooktan dalam air dan bakteri Pseudomonas aeruginosa dalam kultur medium Nutrien Broth (NB) dengan menggunakan teknik pengguncangan. Proses tersebut berlangsung pada kondisi temperatur 35"C, kecepatan shaker 30 rpm dan tekanan 1 aim dengan variasi konsentrasi substrat iso-oktana yang digunakan pada rentang 800 -10000 ppm volum. Secara umum hasil yang diperoleh dalam penelitian ini menunjukkan bahwa semakin tinggi konsentrasi kontaminan, semakin berkurang jumlah massa sel akhir yang dihasilkan, sedang laju pertumbuhan spesifik sel Pseudomonas aeruginosa relalif sama. Pertumbuhan terbaik sel dicapai (rentang kontaminan 800 ppm - 10000 ppm) pada konsentrasi 800 ppm dengan jumlah massa sel akhir sebesar 0,007079 gr/dm . Model pendekatan secara empiris terhadap laju pertumbuhan sel pada penelitian ini mengikuti persamaan lerusalimsky.

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Bioremediation is an alternative way to overcome hydrocarbon waste to restore contaminated water and soil environment. Microorganism such as Pseudomonas aeruginosa had been used to degrade hydrocarbons compounds. This research is a part of a bioremediation research which was conducted in Gas and Petrochemical Engineering Department. This research was conducted in a nutrient broth (NB) culture medium with shaking technique. The experiment was carried out at 35"C, rotation of 30 rpm and 1 aim pressure with iso-octane concentration variation in the range of 800 - 10000 ppm volume. The results show that the higher contaminant concentration, the less cell mass production while the specific growth rate of Pseudomonas aeruginosa were at the relative same rate. The highest cell growth rate was obtained at 800 ppm with the number of final cell was 7.08 10 gr/L. The empiric model of specific growth rate of this research is lerusalimsky.

Abstrak :
Using bioaugmentation and biostimulation approach for contaminated soil bioremediation were investigated and implemented on field scale. We combine those approaches by culturing massively the petrophilic indigenous microorganisms from chronically contaminated soil enriched by mixed manure. Through these methods, bioremediation performance revealed promising results in removing the petroleum hydrocarbons comparatively using metabolite by product such as biosurfactant, specific enzymes and other extra-cellular product which are considered as a difficult task and will impact on cost increase.

Abstrak :
Konsorsium bakteri lokal (gabungan Salipiger bermudensis DQ 178660, Alterierythrobacter evoxidivorans DQ 304436, Alteromonas macleodii Y 18228 dan Vibrio harveyi DQ 146936) pendegradasi senyawa hidrokarbon kontaminan yang diisolasi dari kawasan eksplorasi minyak Cepu Jawa Tengah diuji kemampuannya dalam merombak senyawa hidrokarbon minyak bumi yang mencemari tanah di kawasan industri Krakatau Steel Cilegon. Dalam penelitian ini, karakterisasi produksi biosurfaktan yang dihasilkan konsorsium bakteri dilakukan dengan mengevaluasi pola pertumbuhan, analisis tegangan permukaan, analisis tegangan antarmuka, analisis komposisi kimia dan uji aktivitas emulsifikasi. Pengujian selama 30 hari pengamatan meliputi pH, suhu, tekstur tanah empat fraksi (berpasir, liat kasar, liat halus, berdebu), karbon organik, nitrogen organik, rasio karbon/nitrogen organik, fosfor dan kalium serta analisis sampel tanah tercemar hidrokarbon menggunakan Gas Chromatography-Mass Sphectroscopy (GC-MS). Hasil penelitian menunjukkan bahwa biosurfaktan yang dihasilkan konsorsium bakteri memiliki kemampuan menurunkan tegangan permukaan air lebih tinggi dibanding dengan bakteri tunggal (51 dynes/cm dari 72 dyns/cm), reduksi nilai tegangan antarmuka air dengan minyak paling tinggi dihasilkan konsorsium bakteri (10 dynes/cm), nilai indeks emulsifikasi (93,75%) paling tinggi dihasilkan oleh konsorsium bakteri. Analisis komposisi kimia biosurfaktan yang dihasilkan konsorsium bakteri menunjukkan bahwa biosurfaktan merupakan senyawa kompleks terdiri dari karbohidrat, protein dan lipid. Setelah 30 hari massa inkubasi, hasil analisis GC-MS menunjukkan bahwa bakteri dan konsorsium bakteri mampu merombak senyawa hidrokarbon tersisa yang mencemari tanah di kawasan PT Krakatau Steel Cilegon Banten.;

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Local bacterial consortium (combined of Salipiger bermudensis DQ 178 660, Alterierythrobacter evoxidivorans DQ 304 436, Alteromonas macleodii Y 146 936 and Vibrio harveyi DQ 18228) hydrocarbons degrading contaminants that isolated from oil exploration areas in Cepu Central Java was analyzed for its ability to degrade petroleum hydrocarbons that polluted the soil in industrial area of PT. Krakatau Steel Cilegon. In this study, characterization of biosurfactant produced by bacterial consortium conducted to evaluate growth patterns, analysis of surface tension, interfacial tension, chemical composition and emulsification activity assay. Analysis for 30 days of observation include pH, temperature, soil texture four fractions (sandy, dusty, rough clayey, smooth clayey), organic carbon, organic nitrogen, the ratio of carbon/nitrogen organic, phosphorus and potassium as well as analysis of hydrocarbon contaminated soil samples using Gas Chromatography -Mass Sphectroscopy (GC-MS). The results showed that the biosurfactants produced by bacterial consortium have the ability to lower the surface tension of water is higher than with a single bacterium (51 dynes/cm from 72 dyns/cm), the reduction of the highest values ​​of water interfacial tension with oil produced by bacterial consortium (10 dynes/cm ), the highest value of emulsification index (93.75%) produced by bacterial consortium. Analysis of the chemical composition of biosurfactants produced by bacterial consortium showed that biosurfactants are complex compounds composed of carbohydrates, proteins and lipids. After 30 days of incubation time, the results of GC-MS analysis showed that bacteria and bacterial consortium are capable of overhauling the remaining hydrocarbon compounds that polluted the soil in the area of PT Krakatau Steel Cilegon Banten.

Abstrak :
Bioremediation, involving biostimulation and/or bioaugmentation, is a promising method to overcome oil spills in Cilacap coastal waters. Cilacap coastal area has high risk on oil pollution. This study investigated the stimulatory effect of nitrogen concentration, bacterial density and the composition of bacterial culture in enhancing oil degradation in this area. The applications of 4 different concentrations of Slow Release Fertilizer (SRF) and 2 different densities of bacterial cells in the form of single (RCO/B/08_008) and mixed culture were employed in microcosm experiments for 28 days. The efficacy of combining bacterial culture and fertilizer application in various concentrations was also tested. Oil degradation, bacterial growth and environmental parameters were monitored periodically during the experiments. The results showed that oil degradation rate was more influenced by nutrient concentration (biostimulation) than bacterial number or culture composition (bioaugmentation) added. The efficacy of biostimulation in degrading oil was better than that of bioaugmentation. Biostimulation increased oil degradation up to 6.4 times higher than the control. The optimum of fertilizer concentration added was 7.5 mg N/g (C:N ratio of 1,000:75), which increased depletion rate both in biostimulation-only and the combination of biostimulation with bioaugmentation up to 6.4 and 7.5 times higher than the control, respectively. It is suggested that bioremediation of oil-contaminated sandy beach in Cilacap would be optimal by employing a combination of Slow Release Fertilizer at concentration having C/N ratio = 1,000 : 75 and RCO/B/08_008 culture at density of 0.5 x 108 cells/mL (100% homology with Alcanivorax sp. TE-9).