Study on production of biosurfactant by strain pseudomonas using crude oil as sole carbon source

VIETNAM NATIONAL UNIVERSITY OF AGRICULTURE FACULTY OF BIOTECHNOLOGY GRADUATION THESIS STUDY ON PRODUCTION OF BIOSURFACTANT BY STRAIN Pseudomonas USING CRUDE OIL AS SOLE CARBON SOURCE HANOI - 2022 VIETNAM NATIONAL UNIVERSITY OF AGRICULTURE FACULTY OF BIOTECHNOLOGY GRADUATION THESIS STUDY ON PRODUCTION OF BIOSURFACTANT BY STRAIN Pseudomonas USING CRUDE OIL AS SOLE CARBON SOURCE STUDENT : LE VIET HUNG STUDENT’S CODE : 620391 CLASS : K62CNSHE SUPERVISOR : DR KIEU THI QUYNH HOA ASSOC PROF NGUYEN VAN GIANG HANOI – 2022 COMMITMENT I hereby declare that this is my research and completion, the research results presented in the thesis are honest, and objective, and have never been used to present any subject project I hereby declare that all help in the preparation of this thesis has been thanked, and the sources of information cited in this thesis have been acknowledged Hanoi, May 2022 Sincerely Le Viet Hung i ACKNOWLEDGMENTS First of all, with deep gratitude, I would like to thank Dr Kieu Thi Quynh Hoa, Department of Petroleum Microbiology, Institute of Biotechnology (IBT), Vietnam Academy of Science and Technology (VAST), and Assoc Prof Nguyen Van Giang, Department of Microbial Biotechnology, Vietnam National University of Agriculture (VNUA) are the person who oriented, guided, and at the same time, helped and created the best conditions to help me complete this thesis I would like to express my sincere thanks to the staff of the Department of Petroleum Microbiology, IBT, VAST for their enthusiastic support and guidance during the experiment to complete the experiment into a thesis At the same time, I would like to thank the teachers of the Department of Microbial Biotechnology, VNUA for imparting valuable knowledge and passion for scientific research Finally, I would like to sincerely thank my family and friends who have always accompanied, cared for, and encouraged me throughout the whole process of studying, researching, and completing the thesis Hanoi, May 2022 Sincerely Le Viet Hung ii INDEX COMMITMENT i ACKNOWLEDGMENTS .ii INDEX iii LIST OF ABBREVIATIONS vi LIST OF TABLES vii LIST OF FIGURES viii ABSTRACT x PART I INTRODUCTION 1.1 Preface 1.2 Purpose and requirements: 1.2.1 Purpose 1.2.2 Requirements PART II LITERATURE REVIEW 2.1 Petroleum hydrocarbon contamination (PHC) 2.1.1 Petroleum hydrocarbon contamination in the world 2.1.2 Petroleum hydrocarbon contamination in Vietnam 2.1.3 Effects of oil pollution on ecosystems and people 2.1.4 Mechanism of microbial biodegradation of petroleum hydrocarbons 2.1.5 Methods applied for treatment of petroleum hydrocarbon contaminants 2.2 Biosurfactants 10 2.2.1 Classification of biosurfactants 10 2.2.2 Characterization of biosurfactants 11 2.3 Biosurfactants from microorganisms and their applications 12 2.3.1 Microbial production of biosurfactants 12 2.3.2 Effect of environmental factors on production of biosurfactants 14 2.3.3 The potential application of biosurfactants 16 2.4 Study on biosurfactant producing microorganisms for petroleum hydrocarbon biodegradation 17 iii 2.4.1 In the world 17 2.4.2 In Vietnam 18 2.5 Application of Pseudomonas in petroleum hydrocarbon pollution treatment 19 PART III: MATERIALS AND METHODS 20 3.1 Materials 20 3.1.1 Bacterial strain 20 3.1.2 Crude Oil 20 3.1.3 Culture media 20 3.1.4 Machines and equipments 20 3.2 Research methods 21 3.2.1 Isolation of bacteria using petroleum hydrocarbon as sole carbon source 21 3.2.2 Selection of a bacterial strain capable of biosurfactant production with high emulsification activity on petroleum hydrocarbon substrate (crude oil) 22 3.2.3 Identification of the selected bacterial strain 22 3.2.4 Effect of environmental and culture conditions on biosurfactant production of the selected bacterial strain 24 3.2.5 Determination of total oil content by gravimetric method 24 PART IV: RESULTS 25 4.1 Screening of petroleum hydrocarbon (crude oil) utilizing and bio-surfactant producing bacterial strains 25 4.2 Identification of the selected petroleum hydrocarbon utilizing and biosurfactant producing bacterial strain 25 4.2.1 Morphological characteristics of the DSVK2 strain 25 4.2.2 Classification of the DSVK2 strain by 16S rRNA gene sequence analysis 27 4.2.3 The biosurfactants producing ability on crude oil of the selected bacterial strain 27 iv 4.3 Effect of environmental and culture conditions on biosurfactant production efficiency of DSVK2 strain 28 4.3.1 Effect of crude oil concentration on biosurfactant production efficiency of DSVK2 strain 28 4.3.2 Effect of nitrogen sources on biosurfactant production efficiency of DSVK2 strain 31 4.3.3 Effect of different concentrations of NH4NO3 on biosurfactant production efficiency of DSVK2 strain 33 4.3.4 Effect of pH value on biosurfactant production efficiency of DSVK2 strain 35 4.3.5 Effect of temperature on biosurfactant production efficiency of DSVK2 strain 37 4.3.6 Effect of concentrations of NaCl on biosurfactant production efficiency of DSVK2 strain 39 4.3.7 Effect of bacterial concentrations on biosurfactant production efficiency of DSVK2 strain 41 4.3.8 Biodegradation of crude oil of Pseudomonas sp DSVK2 43 PART V DISCUSSION 45 PART VI: CONCLUSIONS 49 REFERENCES 50 v LIST OF ABBREVIATIONS Abbreviations Explain APG Alkyl polyglycoside BS Biosurfactants CLP Cyclic Lipopeptide E24 Emulsifying index after 24 hours HC Hydrocarbons IBT Institute of Biotechnology MSM Mineral salt medium PAHs Polycyclic aromatic hydrocarbons PHC Petroleum Hydrocarbon Contamination SEM Scanning electron microscope ST Surface tension TABM Total aerobic bacteria medium TPH Total petroleum hydrocarbon VAST Vietnam Academy of Science and Technology VNUA Vietnam National University of Agriculture vi LIST OF TABLES Table 2.1 Large oil spill in the world .4 Table 2.2 Large oil spill in Vietnam .5 Table 2.3 Classification of biosurfactants by microorganisms 11 Table 2.4 Microorganisms capable of biosurfactant production 13 Table 3.1 Equipment used for research 21 vii LIST OF FIGURES Figure 2.1 Mechanism of biodegradation petroleum Figure 4.1 Colony morphology of DSVK2 strain on TABM 26 Figure 4.2 Image of DSVK2 strain under scanning electron microscope 26 Figure 4.3 Biosurfactant of DSVK2 strain during 18 days of incubation 28 Figure 4.4 Biosurfactant production efficiency of DSVK2 during 18 days 28 Figure 4.5 Biosurfactant production of DSVK2 strain at different concentrations of crude oil after 12 days incubation 30 Figure 4.6 Biosurfactant producing of DSVK2 strain with different crude oil content after 12 days incubation 30 Figure 4.7 Biosurfactant producing of DSVK2 strain with different nitrogen sources after 12 days incubation 32 Figure 4.8 Biosurfactant ability of strain DSVK2 with different nitrogen sources after 12 days 32 Figure 4.9 Biosurfactant production of DSVK2 strain at different concentrations of NH4NO3 after 12 days incubation 34 Figure 4.10 Biosurfactant production efficiency of DSVK2 strain with different concentrations of NH4NO3 after 12 days 34 Figure 4.11 Biosurfactant of DSVK2 strain at different pH values after 12 days 36 Figure 4.12 Biosurfactant production efficiency of DSVK2 strain with different pH values after 12 days 36 Figure 4.13 Biosurfactant production of DSVK2 strain at different temperatures after 12 days incubation 38 Figure 4.14 Biosurfactant production efficiency of DSVK2 strain with different temperatures after 12 days 38 viii PART V DISCUSSION Biodegradation of hydrocarbons by microorganisms allows for the conversion of hazardous substances into forms that are less or nontoxic Potential of microorganisms to degrade or transform various petroleum hydrocarbons has been investigated One of the most important characteristics of hydrocarbon-degrading bacteria is the ability to emulsify hydrocarbons in solution by producing biosurfactants that cause dispersion of hydrocarbons in water emulsions, microdroplets of micelles which are subsequently transported into the cell The capability of biosurfactants to enhance organic contaminants availability and biodegradation rates were demonstrated Studies revealed that biosurfactants can enhance hydrocarbon bioremediation Biosurfactant can reduce the surface tension and thus enhance the removal of hydrocarbons by increasing their solubility and making them more available for degradation Several microbial genera such as Acinetobacter, Arthrobacter, Pseudomonas, and Myroides Halomonas, Alcanivorax, Rhodococcus and Halomonas have been used in hydrocarbon degradation studies (Sarshad et al., 2015; Kadam et al., 2019) In which, Pseudomonas which can grow in extreme environmental conditions shows potential for application of hydrocarbon degradation Therefore, the aim of this study is to select a crude oil utilizing Pseudomonas strain for the potential to produce biosurfactant A Pseudomonas strain DSVK2 that has been a potential biosurfactant producing on crude oil as the sole carbon source with 52.8% of emulsification index (E24) isolated from oil-contaminated water at Do Son, Hai Phong, Vietnam This is positive results that have been compared with to the findings of some studies (Kadam et al., 2019; Antai 1990; Thavasi et al., 2007) Based on morphological, biochemical characteristics and sequencing analysis of 16S rDNA, the strain DSVK2 was identified belong to Pseudomonas genera and similarity up to 99.5% with Pseudomonas stutzeri Therefore, the strain DSVK2 45 was designed as Pseudomonas stutzeri DSVK2 In addition, many species belong to genus Pseudomonas were reported for their biosurfactant activities (EI Mahdi et al., 2016; Thavasi et al., 2011; Liu et al., 2018) Despite all advantages mentioned above, only a few microbial species are produced at large scale for commercial applications, mainly due to their ability of biosurfactant production Therefore, aiming at the further use of the Pseudomonas sp DSVK2 strain in hydrocarbon bioremediation, the biosurfactant production yields must be improved which can be achieved through the optimization of culture medium and conditions, specifically of carbon and nitrogen source, pH value, temperature, salinity, and the concentration of inoculated bacteria In this study, the emulsification of Pseudomonas sp DSVK2 were examined under a variety of conditions, such as the choice of crude oil as the sole carbon source, nitrogen source for energy requirements, and the effect of different environmental conditions like salinity (concentration of NaCl), pH value and temperature Because this strain was isolated in the environment containing rich hydrocarbon components in crude oil it leads to an especially important assessment of the crude oil concentration As mentioned earlier, the effects of crude oil are noticeably clear, it is the ideal source of nutrition for the strain DSVK2 From six different concentrations of crude oil, the concentration of 3% (w/v) crude oil was found to be favorable for this strain (E24 is 56 %) We found this result to be a bright spot like other study that have also reported the same (Zhang et al., 2012) In nature as well as in chemistry, there are many different nitrogen sources, however, for each strain of microorganisms there are diverse way to utilize nitrogen sources In our study, Pseudomonas sp DSVK2 recognized tends to use ammonium nitrate (NH4NO3) as the best nitrogen source to increase biosurfactant production through of emulsification index E24 reached 60.5 % This result is like an analysis of strains of Pseudomonas 46 fluorescens of (Abouseoud et al., 2008, Saikia et al., 2012) At the same time, there are many concentrations of ammonium nitrate that also affect the ability of biosurfactants production, in a variety of NH4NO3 concentrations, we determined that 0.4% (w/v) was the most optimal nitrogen concentration for the emulsification formation of Pseudomonas stutzeri DSVK2 (E24: 64%) Furthermore, current attention is focusing on biosurfactant-producing bacteria under extreme conditions for commercial utilization and usefulness Therefore, this study has simulated the growth of Pseudomonas stutzeri DSVK2 in different environment conditions, the change of each condition will directly affect the efficiency of biosurfactant production and petroleum hydrocarbon biodegradation process In the final, we optimized the culture medium under pH 8.0, culture temperature 30oC, and NaCl concentration reached 2% (w/v) Under these optimal conditions, the desirable emulsification index reached 66% This fact may be related to the conditions in marine environments with pH (7-8.5), salt ranges from 30% with NaCl is a main element of seawater and the temperature fluctuates greatly Our finding could be comparable with the results of (Harikrishnan, 2021), they observed that the E 24 of Pseudomonas stutzeri biosurfactant activity was stable in pH range from to 10, and stable at pH 7.5, they also stated that temperatures at 30-37°C resulted in a optimize yield of biosurfactant production by Pseudomonas stutzeri SJ3 In biodegradation results, analysis on crude oil decomposition showed Pseudomonas stutzeri has 63% biodegradation efficiency of crude oil after 20 days of incubation Recently, Rehmanet et al (2021 reported crude oil degradation by Pseudomonas aeruginosa and Meyerozyma sp in the range of 91% and 87% degradation rates On other hand, (Deivakumari et al., 2020) announced petroleum hydrocarbon biodegradation by Pseudomonas aeruginosa (DKB1) in the range of 63.38% over 60 days The present study demonstrates that the Pseudomonas stutzeri capable to producing biosurfactant which possesses an efficient crude oil degradation property and is potentially useful 47 for biodegradation of petroleum hydrocarbon contaminated sites The application of DSVK2 in the treatment of petroleum hydrocarbon contamination will be further studied and announced in a suitable time 48 PART VI: CONCLUSIONS Based on the screening methods, a bacterial strain (designed as DSVK2) was isolated from oil-contaminated water at Do Son, Hai Phong This strain has the ability to utilize crude oil as the sole carbon source and produce biosurfactant on this substrate with an E24 index of 52.8% after 12 days of incubation DSVK2 strain was identified through morphological characteristics and sequencing analysis of 16S rDNA This strain is similar to 99.5 % with the 16S rDNA sequence of Pseudomonas stuzeri, therefore was designed as Pseudomonas sp DSVK2 The suitable culture conditions for biosurfactant production of Pseudomonas sp DSVK2 are 3% (w/v) crude oil, 0.4% (w/v) NH4NO3, 2% (w/v) NaCl, 3% (v/v) bacterial concentration, pH 8, 30 oC Under these conditions, the biosurfactant produced by this strain was the highest with E24 reaching 69%, an increase of ~16.2% compared to the E24 before selecting the suitable factors (52.8%) The strain Pseudomonas sp DSVK2 showed quite a high degradation efficiency (63%) after 20 day-experiment in the suitable conditions The crude oil content decreased from 28,950 to 10,712 mg/l after 20 day-experiment These effective biosurfactant-producing bacteria represent a promising option for many applications aimed at the biodegradation of hydrocarbon and bioremediation of petroleum hydrocarbon contaminated sites that has the ability of petroleum hydrocarbon utilization and bio-surfactant production 49 REFERENCES Vietnamese Đặng Thị Yến, Nguyễn Thành Bình, Nguyễn Thị Yên, Vương Thị Nga, Kiều Thị Quỳnh Hoa (2018) Nghiên cứu chủng vi khuẩn sinh tổng hợp chất hoạt động bề mặt sinh học nguồn chất dầu thô nhằm ứng dụng cơng nghiệp dầu khí xử lý ô nhiễm dầu Hội nghị Khoa học công nghệ sinh học tồn quốc 2018; 1198-1202 Đỗ Cơng Thung cs, 2007, Báo cáo cục hàng hải Việt Nam, 2010 Kiều Thị Quỳnh Hoa cộng (2016, 2017), Khả tạo chất hoạt động bề mặt sinh học phân hủy dầu thô chủng nấm men 1214-BK14 phân lập từ giếng khai thác dầu mỏ Bạch Hổ, Vũng Tàu Tạp chí khoa học 2016, 38(2):179-185 Kiều Thị Quỳnh Hoa, Nguyễn Vũ Giang, Nguyễn Thị Yên, Mau Đức Huynh, Nguyễn Hữu Đạt, Vương Thị Nga, Nguyễn Thị Thu Hà, Phạm Thị Phượng (2020), Nâng cao hiệu xử lý ô nhiễm dầu chủng Bacillus sp VTVK15 cố định lên xốp Polyurethane (PUF) Tạp chí công nghệ sinh học (2020), 18(3) tr: 581-588 Lại Thúy Hiền, Nguyễn Thị Yên, Vương Thị Nga (2013), Vi khuẩn tạo chất hoạt hóa bề mặt sinh học Rhodococcus ruber TD2 phân lập từ nước ô nhiễm dầu ven biển Vũng Tàu Sinh học, số tr.454-460 Lê Phi Nga cộng (2006 -2008), Chất hoạt động bề mặt sinh học sinh từ vi khuẩn phân hủy dầu SG7 khả sử dụng xử lý bùn nhiễm dầu kim loại nặng quy mô PTN Vương Thị Nga, Nguyễn Thị Yên, Kiều Thị Quỳnh Hoa, Lại Thúy Hiền (2014), Hiệu xử lý ô nhiễm dầu ven biển chế phẩm chất hoạt hóa bề mặt sinh học tổng hợp vi sinh vật biển Công nghệ sinh học 2014, (số 1), tr.189-196 50 English Abouseoud, M., Maachi, R., Amrane, A., Boudergua, S., & Nabi, A (2008) Evaluation of different carbon and nitrogen sources in production of biosurfactant by Pseudomonas fluorescens Desalination, 223(1-3), 143-151 Arẳjo, H., Andrade, R.F., Montero-Rodríguez, D., Rubio-Ribeaux, D., Silva, C.A., & Campos-Takaki, G.M (2019) Sustainable biosurfactant produced by Serratia marcescens UCP 1549 and its suitability for agricultural and marine bioremediation applications Microbial Cell Factories, 18 10 Antai, S P (1990) Biodegradation of Bonny light crude oil by Bacillus sp and Pseudomonas sp Waste management, 10(1), 61-64.Books received (1986) The Annals of Regional Science, 20(1), 145–149 11 Brown, T.A., 2001 Gene cloning DNA analysis 4th ed P.O Box 88 Manchester M60 QD UK 12 Cooper, D G et al 1984 Production of a Biosurfactant from Torulopsis bombicol Appl Environ Microbiol 47:173-176 13 Chen, J., Huang, P., Zhang, K.Y., & Ding, F (2012) Isolation of biosurfactant producers, optimization and properties of biosurfactant produced by Acinetobacter sp from petroleum‐ contaminated soil Journal of Applied Microbiology, 112 14 Das, K., & Mukherjee, A K (2007) Crude petroleum-oil biodegradation efficiency of Bacillus subtilis and Pseudomonas aeruginosa strains isolated from a petroleum-oil contaminated soil from North-East India Bioresource Technology, 98(7), 1339–1345 15 Das, N., & Chandran, P (2011) Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview Biotechnology Research International, 2011, 1–13 51 16 Deivakumari, M., Sanjivkumar, M., Suganya, A M., Prabakaran, J R., Palavesam, A., & Immanuel, G (2020) Studies on reclamation of crude oil polluted soil by biosurfactant producing Pseudomonas aeruginosa (DKB1) Biocatalysis and Agricultural Biotechnology, 29, 101773 17 El Mahdi, A.M., Aziz, H.A., Abu Amr, S.S et al Isolation and characterization of Pseudomonas sp NAF1 and its application in biodegradation of crude oil Environ Earth Sci 75, 380 (2016) 18 El-Sersy, N.A (2012) Plackett-Burman Design to Optimize Biosurfactant Production by Marine Bacillus subtilis N10 19 French-McCay, D P (2004) Oil spill impact modeling: development and validation Environmental Toxicology and Chemistry, 23(10), 2441 20 Fritt-Rasmussen, J., & Brandvik, P J (2011) Measuring ignitability for in situ burning of oil spills weathered under Arctic conditions: From laboratory studies to large-scale field experiments Marine Pollution Bulletin, 62(8), 1780–1785 21 Goldstein, B D., Osofsky, H J., & Lichtveld, M Y (2011) The Gulf Oil Spill New England Journal of Medicine, 364(14), 1334–1348 22 Gong, Y., Zhao, X., Cai, Z., O’Reilly, S., Hao, X., & Zhao, D (2014) A review of oil, dispersed oil and sediment interactions in the aquatic environment: Influence on the fate, transport and remediation of oil spills Marine Pollution Bulletin, 79(1–2), 16–33 23 Grey, C J (1999) The Cost of Oil Spills from Tankers: An Analysis of IOPC Fund Incidents International Oil Spill Conference Proceedings, 1999(1), 41–47 24 Gudiña, E J., Rodrigues, A I., Alves, E., Domingues, M R., Teixeira, J A., & Rodrigues, L R (2015) Bioconversion of agro-industrial by- 52 products in rhamnolipids toward applications in enhanced oil recovery and bioremediation Bioresource technology, 177, 87-93 25 Kadam, D., & Savant, D (2019) Biosurfactant production from shrimp shell waste by Pseudomonas stutzeri, 1411-1418 26 Karanth, N., Deo, P., & Veenanadig, N.K (1999) Microbial production of biosurfactants and their importance Current Science, 77, 116-126 27 Hassanshahian, M., Emtiazi, G., & Cappello, S (2012) Isolation and characterization of crude-oil-degrading bacteria from the Persian Gulf and the Caspian Sea Marine Pollution Bulletin, 64(1), 7–12 28 Harikrishnan, Sekar & Jayalakshmi, Singaram & Alsalhi, Mohamad & Kartick, Alager & S., Devanesan & Rajasekar, Aruliah (2021) Characterization of Biosurfactant From Pseudomonas Stutzeri SJ3 for Remediation of Crude Oil-Contaminated Soil 10.21203/rs.3.rs497731/v1 29 Hoang, P H., Hoang, A T., Chung, N H., Dien, L Q., Nguyen, X P., & Pham, X D (2017) The efficient lignocellulose-based sorbent for oil spill treatment from polyurethane and agricultural residue of Vietnam Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 40(3), 312–319 30 Hollaway, S L., Faw, G M., & Sizemore, R K (1980) The bacterial community composition of an active oil field in the northwestern Gulf of Mexico Marine Pollution Bulletin, 11(6), 153–156 31 Ikhwani, A Z N., Nurlaila, H S., Ferdinand, F D K., Fachria, R., Hasan, A E Z., Yani, M., Suryani (2017) Preliminary study optimization of pH and salinity for biosurfactant production from Pseudomonas aeruginosain diesel fuel and crude oil medium IOP Conference Series: Earth and Environmental Science, 58, 012056 53 32 Jones, J G., Knight, M., & Byrom, J A (1970) Effect of Gross Pollution by Kerosine Hydrocarbons on the Microflora of a Moorland Soil Nature, 227(5263), 1166 33 Lal, B., & Khanna, S (1996) Degradation of crude oil by Acinetobacter calcoaceticus and Alcaligenes odorans Journal of Applied Bacteriology, 81(4), 355–362 34 Latha, R., Kalaivani, R (2012) Bacterial Degradation of Crude Oil by Gravimetric Analysis Advances in Applied Science Research (5):2789-2795 35 Lessard, R., & DeMarco, G (2000a) The Significance of Oil Spill Dispersants Spill Science & Technology Bulletin, 6(1), 59–68 36 Lessard, R., & DeMarco, G (2000b) The Significance of Oil Spill Dispersants Spill Science & Technology Bulletin, 6(1), 59–68 37 Li, Q., Huang, Y., Wen, D., Fu, R., & Feng, L (2020) Application of alkyl polyglycosides for enhanced bioremediation of petroleum hydrocarbon-contaminated soil using Sphingomonas changbaiensis and Pseudomonas stutzeri Science of The Total Environment, 719, 137456 38 Liu, H., Yao, J., Yuan, Z., Shang, Y., Chen, H., Wang, F., Choi, M M (2014) Isolation and characterization of crude-oil-degrading bacteria from oil-water mixture in Dagang oilfield, China International Biodeterioration & Biodegradation, 87, 52–59 39 Liu, W., Sun, D., Li, C., Liu, Q., & Xu, J (2006) Formation and stability of paraffin oil-in-water nano-emulsions prepared by the emulsion inversion point method Journal of Colloid and Interface Science, 303(2), 557–563 40 Liu, W.J., Duan, X.D., Wu, L.P et al Biosurfactant Production by Pseudomonas aeruginosa SNP0614 and its Effect on Biodegradation of Petroleum Appl Biochem Microbiol 54, 155–162 (2018) 54 41 Makkar, R S., & Rockne, K J (2003) Comparison of synthetic surfactants and biosurfactants in enhancing biodegradation of polycyclic aromatic hydrocarbons Environmental Toxicology and Chemistry, 22(10), 2280 42 Makkar, R.S., Cameotra, S.S Biosurfactant production by microorganisms on unconventional carbon sources J Surfact Deterg 2, 237–241 (1999) 43 McNutt, M K., Camilli, R., Crone, T J., Guthrie, G D., Hsieh, P A., Ryerson, T B., Savas, O., & Shaffer, F (2011) Review of flow rate estimates of the Deepwater Horizon oil spill Proceedings of the National Academy of Sciences, 109(50), 20260–20267 44 Md, F (2012) Biosurfactant: Production and Application Journal of Petroleum & Environmental Biotechnology, 03(04) 45 Mega, E R (2022) Unprecedented oil spill catches researchers in Peru off guard Nature 46 Mujumdar S, Joshi P,Karve N (2019) Production, characterization, and applications of bioemulsifiers (BE) and biosurfactants (BS) produced by Acinetobacter spp: A review J Basic Microbiol, 59, 277–287 47 Müller, M M., & Hausmann, R (2011) Regulatory and metabolic network of rhamnolipid biosynthesis: traditional and advanced engineering towards biotechnological production Applied microbiology and biotechnology, 91(2), 251-264 48 Mukherjee, A K., & Das, K (2010) Microbial surfactants and their potential applications: an overview Biosurfactants, 54-64 49 Mujumdar, S., Joshi, P., & Karve, N (2019) Production, characterization, and applications of bioemulsifiers (BE) and biosurfactants (BS) produced byAcinetobacterspp.: A review Journal of Basic Microbiology, 59(3), 277–287 55 50 Mukherjee, A (2007) Potential application of cyclic lipopeptide biosurfactants produced by Bacillus subtilis strains in laundry detergent formulations Letters in Applied Microbiology, 45(3), 330– 335 51 Mukred, A M., Hamid, A A., Hamzah, A., & Wan Yusoff, W M (2008) Growth Enhancement of Effective Microorganisms for Bioremediation of Crude Oil Contaminated Waters Pakistan Journal of Biological Sciences, 11(13), 1708–1712 52 Mulkins-Phillips, G J., & Stewart, J E (1974) Distribution of hydrocarbon-utilizing bacteria in Northwestern Atlantic waters and coastal sediments Canadian Journal of Microbiology, 20(7), 955– 962 53 Mulligan, C N (2005) Environmental applications for biosurfactants Environmental Pollution, 133(2), 183–198 54 Nguyen, P Q P (2018) The Oil Spill Incident in Vietnam European Journal of Engineering Research and Science, 3(7), 55 Pacheco, G.J., Ciapina, E.M., Gomes, E.D., & Júnior, N (2010) Biosurfactant Production by Rhodococcus Erythropolis and its Application to Oil Removal Brazilian Journal of Microbiology, 41, 685 – 693 56 Pinholt, Y., Struwe, S., & Kjoller, A (1979) Microbial changes during oil decomposition in soil Ecography, 2(3), 195–200 57 Pirôllo, M P., Mariano, A P., Lovaglio, R B., Costa, S G., Walter, V., Hausmann, R., & Contiero, J (2008) Biosurfactant synthesis by Pseudomonas aeruginosa LBI isolated from a hydrocarboncontaminated site Journal of applied microbiology, 105(5), 1484– 1490 56 58 Thavasi, R., Subramanyam Nambaru, V.R.M., Jayalakshmi, S et al Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources Indian J Microbiol 51, 30–36 (2011) 59 Rehman, R., Ali, M I., Ali, N., Badshah, M., Iqbal, M., Jamal, A., & Huang, Z (2021) Crude oil biodegradation potential of biosurfactant-producing Pseudomonas aeruginosa and Meyerozyma sp Journal of Hazardous Materials, 418, 126276 60 Saikia, R R., Deka, S., Deka, M., & Sarma, H (2012) Optimization of environmental factors for improved production of rhamnolipid biosurfactant by Pseudomonas aeruginosa RS29 on glycerol Journal of Basic Microbiology, 52(4), 446-457 61 Samanta, S K., Singh, O V., & Jain, R K (2002) Polycyclic aromatic hydrocarbons: environmental pollution and bioremediation Trends in Biotechnology, 20(6), 243–248 62 Sekhar, N U (2005) Integrated coastal zone management in Vietnam: Present potentials and future challenges Ocean & Coastal Management, 48(9–10), 813–827 63 Shekhar, S., Sundaramanickam, A., Saranya, K., Meena, M., Kumaresan, S., & Balasubramanian, T (2018) Production and characterization of biosurfactant by marine bacterium Pseudomonas stutzeri (SSASM1) International Journal of Environmental Science and Technology, 16(8), 4697–4706 64 Silva MA, Silva AF, Rufino RD, Luna JM, Santos VA, Sarubbo LA Production of Biosurfactants by Pseudomonas Species for Application in the Petroleum Industry Water Environ Res 2017 Feb 1;89(2):117-126 65 Silva, R., Almeida, D., Rufino, R., Luna, J., Santos, V., & Sarubbo, L (2014) Applications of Biosurfactants in the Petroleum Industry and 57 the Remediation of Oil Spills International Journal of Molecular Sciences, 15(7), 12523–12542 66 Sun, W., Cao, W., Jiang, M., Saren, G., Liu, J., Cao, J., Naz, I (2018) Isolation and characterization of biosurfactant-producing and diesel oil degrading Pseudomonassp CQ2 from Changqing oil field, China RSC Advances, 8(69), 39710–39720 67 Suwansukho, P., Rukachisirikul, V., & Kawai, F (2008) Production and applications of biosurfactant from Bacillus subtilis MUV4 Songklanakarin Journal of Science & Technology, 30 68 Suzuki, T., Hayashi, K., Fujikawa, K., & Tsukamoto, K (1965) The chemical structure of polymyxin E: the identities of polymyxin e1 with colistin and of polymyxin E2 with colistin B Journal of biochemistry, 57, 226-7 69 Thakur, P., Saini, N K., Thakur, V K., Gupta, V K., Saini, R V., & Saini, A K (2021) Rhamnolipid the Glycolipid Biosurfactant: Emerging trends and promising strategies in the field of biotechnology and biomedicine Microbial Cell Factories, 20(1) 70 Thavasi, R., Jayalakshmi, S., Balasubramanian, T., & Banat, I M (2007) Effect of salinity, temperature, pH and crude oil concentration on biodegradation of crude oil by Pseudomonas aeruginosa 71 Tian, X., Wang, X., Peng, S., Wang, Z., Zhou, R., Tian, H (2018) Isolation, screening, and crude oi degradation characteristics of hydrocarbons-degrading bacteria for treatment of oily wastewater Water Sci Technol 78 (12): 2626–2638 72 Tsai, C C., Cheng, Y T., Shen, L C., Chang, K C., Ho, I T., Chu, J H., & Chung, W S (2013) Biscalixarene Derivative As a Very Efficient Phase Selective Gelator for Oil Spill Recovery Organic Letters, 15(22), 5830–5833 58 73 Varjani, S., & Upasani, V N (2021) Bioaugmentation of Pseudomonas aeruginosa NCIM 5514 – A novel oily waste degrader for treatment of petroleum hydrocarbons Bioresource Technology, 319, 124240 74 Ventikos, N (2004) A high-level synthesis of oil spill response equipment and countermeasures Journal of Hazardous Materials, 107(1–2), 51–58 75 Zahed, M A., Aziz, H A., Isa, M H., & Mohajeri, L (2010) Effect of Initial Oil Concentration Biodegradation in and Dispersant Contaminated on Seawater Crude Oil Bulletin of Environmental Contamination and Toxicology, 84(4), 438–442 Internet 76 Dan Collyns (2022) Oil spill at sea: who will pay for Peru’s worst environmental disaster? https://www.theguardian.com/environment/2022/mar/07/oil-spill-atsea-who-will-pay-peru-worst-environmental-disaster 77 https://tailieu.vn/doc/chat-hoat-dong-be-mat-321180.html Ứng dụng chất hoạt động bề mặt sinh học 78 IEA (2021), Oil Market Report - October 2021, IEA, Paris https://www.iea.org/reports/oil-market-report-october-2021 79 NOAA (2021) How does oil impact marine life? https://oceanservice.noaa.gov/facts/oilimpacts.html 80 https://123docz.net/document/7287503-buoc-dau-nghien-cuu-mot-sochung-vi-khuan-pseudomonas-de-xu-ly-nuoc-thai-cong-nghiep-chebien-sua.htm 81 https://issuu.com/fasett/docs/norog_milj rapport13_eng_web The Norwegian Oil Industry Association Environmental Report 2004 82 https://xulydau.com/thong-ke-nhung-vu-tran-dau-o-viet-nam/ 83 https://congnghiepmoitruong.vn/ung-pho-su-co-tran-dau-tai-viet-nam7959.html 59