نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه میکروبیولوژی، دانشکده علوم،کشاورزی وفناوری های نوین، دانشگاه ازاد اسلامی واحد شیراز، شیراز، ایران

2 گروه میکروبیولوژی، دانشکده علوم پایه، دانشگاه آزاد اسلامی واحد رشت، رشت، ایران

3 گروه فیزیک، دانشکده علوم پایه، دانشگاه آزاد اسلامی واحد مسجد سلیمان، مسجد سلیمان، ایران

چکیده

سابقه و هدف:
در چند دهه اخیر،زایلن به همراه تعدادی دیگر از ترکیب­ های آروماتیک موجود در نفت خام و دیگر محصول­ های پتروشیمی به‌عنوان یکی از آلاینده‌های مهم خاک محسوب شده­ اند، بنابراین هدف از این بررسی، یافتن سویه باکتری برای تجزیه زیستی این ترکیب و افزایش راندمان تجزیه این ترکیب به کمک تثبیت این باکتری بر روی ترکیب­ هایی با ساختار نانویی مانند اکسیدگرافن است.
مواد و روش‌ها:
در این پژوهش، تجزیه زیستی زایلن با استفاده از باکتری‌های آزاد و تثبیت‌شده به کمک اکسید گرافن در شرایط بهینه بررسی شد. باکتری‌های تجزیه‌کننده زایلن از خاک‌آلوده جداسازی شد و با استفاده از توالی ژن S rDNA 16 شناسایی گردید. که باکتری شناسایی شده Sphingomonas paucimobilis سویه TY4-HX:  بود. برای تجزیه زایلن با استفاده از سلول‌های آزاد و تثبیت‌شده ، میزان بهینه pH، دما، و غلظت زایلن به کمک روش RSM به ترتیب برابر با7، c°32وg/l  5/1 تعیین شد.
نتایج و بحث:
سلول‌های آزاد تحت شرایط بهینه قادر به تجزیه زیستی زایلن به مقدار  8/45 % طی 24 ساعت بود. در این مطالعه از اکسید گرافن به‌منظور تثبیت باکتری Sphingomonas paucimobilis سویه TY4-HX  استفاده شد. با استفاده از روش‌های FTIR و SEM مشخص شد که این سویه بااتصال به سطح اکسید گرافن قادر به ایجاد بیوفیلم شده است. باکتری‌های تثبیت‌شده به این روش قادر به تجزیه زیستی زایلن به مقدار بیش از 3/86 % تحت شرایط بهینه و در زمان 24 ساعت بود.
نتیجه‌گیری:
با توجه به نتایج به ­دست آمده، باکتری‌های تثبیت‌شده نسبت به همان سویه از باکتری‌های آزاد، از عملکرد بهتری در پالایش خاک‌آلوده به زایلن برخوردار بودند.

کلیدواژه‌ها

عنوان مقاله [English]

Xylene biodegradation by free and immobilized Sphingomonas paucimobilis strain TY4-HX on graphene oxide

نویسندگان [English]

  • Hossein Mohammadpour 1
  • Mahdi Shahriarinour 2
  • Ramin Yousefi 3

1 Department of Microbiology, Shiraz Branch, Islamic Azad University, Shiraz, Iran

2 Department of Microbiology, Faculty of Basic Sciences, Rasht Branch, Islamic Azad University, Rasht, Iran

3 Department of Physics, Masjed-Soleiman Branch, Islamic Azad University, Masjed-Soleiman, Iran

چکیده [English]

Introduction:
In recent decades, xylene has been considered as one of the most important pollutants in soil, along with other aromatic compounds in crude oil and other petrochemicals. Therefore, the aim of this study was to find bacteria for the biodegradation of this compound and to increase the degradation efficiency of this compound with the help of immobilizing the bacterium on compounds with a nanostructure such as graphene oxide.
Material and methods:
In the current study, biodegradation of xylene by free and immobilized bacteria on graphene oxide was studied under optimized conditions. Isolated xylene degrading bacteria from contaminated soils were identified based on 16S rDNA gene sequencing and submitted to gene bank as Sphingomonas paucimobilis strain TY4-HX. Using response surface methodology, optimum values of pH, temperature and xylene concentration for xylene degradation by free and immobilized cells were determined as 7, 32ºC and 1.5g/l, respectively.
Results and discussion:
Free bacterial cells were able to degrade 45.8% of the xylene after 24h under optimized conditions. Analyzes by Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscope (SEM) showed that the strain adhered onto the Graphene oxide surface and developed a biofilm. Immobilized cells were able to degrade up to 86.3% of the xylene after 24h under optimized conditions.
Conclusion:
Our results indicated that free and immobilized Bacteria had a suitable application potential in the treatment of xylene-containing soils.

کلیدواژه‌ها [English]

  • Biodegradation
  • Graphene oxide
  • Response surface methodology
  • SEM
  • Xylene

Aivalioti, M., Vamvasakis, I. and Gidarakos, E., 2010. BTEX and MTBE adsorption onto raw and thermally modified diatomite. Journal of Hazardous Materials. 178 (1-3), 136-43.

ATSDR., 2007. Interaction profile for Benzene, ethylbenzene, toluene and Xylene (BTEX)Agency for Toxic substances and disease Registry. Us Department of Health Human Services, Atlanta.

Ayat, E.E., Muftah, T., El-Naas, H. and Janice A.A., 2017. Biodegradation of BTEX: optimization through response surface methodology. American Journal of Engineering and Applied Sciences. 10 (1), 20-31.

Azimi, H.R., Ghoranneviss. M. and Elahi, M., 2016. Excellent photovoltaic and UV detector applications of ZnS/rGO nanocomposites synthesized by a green method. Ceramics International, 42(12), 14094–14099.

Behzadi, M. and Mirzaei, M., 2016. Poly (o-anisidine)/graphene oxide nano sheets composite as a coatingfor the headspace solid-phase microextraction of benzene, toluene, ethylbenzene and Xylenes. Journal of Chromatography A. 1443(22), 35–42.

Berlendis. S., Lascourreges, J., Schraauwers, B., Sivadon, P. and Mago, M.T., 2010. Anaerobic biodegradation of BTEX by original bacterial communities from an underground gas storage aquiferEnvironmental Science & Technology. 44(9), 3621–3628.

Bina, B., Amin, M.M., Rashidi, A. andPourzamani, H., 2012. Benzene and toluene removal by carbon nanotubes from aqueous solution. Archives of Environmental Protection. 38(1), 3-35.

Brigmon, R.,Camper, D. and Stutzenberger, F., 2002. Bioremediation of compounds hazardous health and the environment. Progress in Industrial microbiology. 36, 1-28.

Dursun, A.Y. and Tepe, O., 2005. Internal mass transfer effect on biodegradation of phenol by Ca-alginate immobilized Ralstonia eutropha. Journal of Hazardous Materials. 126(1-3), 105-111.

Firmino, P.I.M., Farias, R.S., Buarque, P.M.C. Costa, M.C., Rodriguez, E., Lopes, A.C. and dos Santos, A.B., 2015. Engineering and microbiological aspects of BTEX removal in bioreactors under sulfate-reducing conditions. Chemical Engineering Journal. 260, 503-512.

Garrigues, S., Gallignani, M. and De la Guardia. M., 1992. Simultaneous determination of ortho-, meta- and para-Xylene by flow injection-Fourier transform infrared spectroscopy. Analyst. 117, 1849-1853.

Guo, H., Yao, J., Chen, H., Wang, J., Masakorala, K., Jin, Y., Richnow, H.H. and Blake, R.E., 2012. Substrate interactions during biodegradation of benzene/alkyl benzene mixtures by Rhodococcus sp. ustb-1. International Biodeterioration & Biodegradation. 75, 124-130.

Huang, W., Xue, A., Niu, H., Jia, Z. and Wang, J., 2009. Optimised ultrasonic-assisted extraction of flavonoids from Folium eucommiae and evaluation of antioxidant activity in multi-test systems in vitro Food Chemistry. 114(3), 1147–1154.

Jean, j., Lee, M.K., Wang, S.M., Chattopadhyay, P. and Maity, J.P., 2008. Effects of inorganic nutrient levels on the biodegradation of benzene, toluene, and Xylene (BTX) by Pseudomonas spp. in a laboratory porous media sand aquifer model. Bioresource Technology. 99(16), 7807–7815.

Jin, H.M., Choi, E.J. and Jeon, C.O., 2013. Isolation of a BTEX-degrading bacterium, Janibacter sp. SB2, from a sea-tidal flat and optimization of biodegradation conditions. Bioresource Technology. 145, 57-64.

Kolangikhah, M., Maghrebi, M., Ghazvini, K. and Farhadian, N., 2012. Separation of Salmonella typhimurium bacteria from water using MWCNTs arrays. International Journal of Nanoscience and Nanotechnology. 8(1), 23-10.

Madueno, L., Coppotelli, B.M., Alvarez, H.M. and Morelli, I.S., 2011. Isolation and characterization of indigenous soil bacteria for bioaugmentation of PAH contaminated soil of semiarid Patagonia, Argentina. International Biodeterioration & Biodegradation. 65(2), 345-351. Mesgari Shadi. A., Yaghmaei. S., Vafaei. F., Khataee. A. and Hejazi. M., 2015. Degradation of benzene, toluene, and xylene (BTX) from aqueous solution by isolated bacteria from contaminated sites. Research on Chemical Intermediates. 41(1), 265–275.

Nel, A., Xia, T., Madler, L. and Li, N., 2006. Toxin potential of material at the nano level. Journal Science. 311(5761), 622 -627

Nouri.M., Moghaddam Saray.A., Azimi. H.R. and Yousefi. R., 2017. High solar-light photocatalytic activity of using Cu3Se2/rGO nanocomposites synthesized by a green co-precipitation method. Solid State Sciences. 73, 7-12.

Pourmand, S., Abdouss, M. and Rashidi, A.M., 2015. Preparation of nanoporous graphene via nanoporous zincoxide and its application as a nano adsorbent for benzene, toluene and xylenes removal. International Journal of Environmental Research. 9(4), 1269-1276.

Pourzamani, H.R., Bina, B., Rashidi, A.M. and Amin, M.M., 2012. Performance of raw and regenerated multi- and single-walled carbon nanotubes in xylene removal from aqueous solutions. International Journal of Environmental Health Engineering. 1(1), 20-23.

Ranya, A., Amer, M., Nasier, M. and Ehab, R.E., 2008. Biodegradation of Monocyclic Aromatic Hydrocarbons by a Newly Isolated Pseudomonas strain. Biotechnology. 7, 630-640.

Singh, R.S. and Celin, M., 2010. Biodegradation of BTEX (Benzene, Tolune, EthylBenzene, and Xylene) compounds by Bacterial strain under Aerobic conditions. Journal of Ecobiotechnology. 2(4), 27-32.

Stefani, F.O.P., Bell, T.H., Marchand, C., Providencia.I., Yassimi, A.E., St-Arnaud, M. and Hijri, M., 2015. Culture-Dependent and -Independent Methods Capture Different Microbial Community Fractions in Hydrocarbon-Contaminated Soils. PLoS ONE. 10(6), e0128272.

Story, S., Kline, E., Hughes, T., Riley, M. and Hayasaka, M., 2004. Degradation of Aromatic Hydrocarbons by Sphingomonas paucimobilis Strain EPA505. Archives of Environmental Contamination and Toxicology. 47(2), 168–176.

Yan, F.F., Wu, C., Cheng, Y.Y., He, Y.R., Li, W.W. and Yu, H.Q., 2013. Carbon nanotubes promote Cr (VI) reduction by alginate-immobilized Shewanella oneidensis MR-1. Biochemical Engineering Journal. 77 (15), 183-189.

Yan, Z., Daban, L., Tianzhen, J., Letao, W., Shaoxiong, L., Yue, Z., Chunming, W., Haijing, H. and Yongling, D., 2013. Biodegradation of Phenol Using Bacillus cereus WJ1 and Evaluation of Degradation Efficiency Based on a Graphene-Modified Electrode. International Journal of Electrochemical Science. 8(3), 504 – 519.

Yoon, S.H., Ha, S.M., Kwon, S., Lim, J., Kim, Y., Seo, H. and Chun, J., 2017. Introducing EzBioCloud: A taxonomically united database of 16S rRNA and whole genome assemblies. International Journal of Systematic and Evolutionary Microbiology. 67(5), 1613-1617.

Zhao, X., Wang, L., Bai, S., Yang, J. and Qi, S., 2017. Pseudomonas sp. ZXY-1, a newly isolated and highly efficient atrazine-degrading bacterium, and optimization of biodegradation using response surface methodology. Journal of Environmental Sciences. 54, 152-159