ORIGINAL PAPER Self-immobilised bacterial consortium culture as ready-to-use seed for crude oil bioremediation under various saline conditions and seawater W. Kok Kee • H. Hazaimeh • S. A. Mutalib • P. S. Abdullah • S. Surif Received: 1 August 2013 / Revised: 11 April 2014 / Accepted: 10 May 2014 / Published online: 4 June 2014 Ó Islamic Azad University (IAU) 2014 Abstract Biodegradation of crude oil hydrocarbon by microorganisms in seawater is generally slow because of the harsh environmental condition due to high salinity. The aim of this study was to compare sawdust (SD) and oil palm empty fruit bunch wastes as suitable carrier material to immobilise hydrocarbon-degrading bacterial consortium culture to accelerate and improve crude oil degradation in seawater. The consortium culture was found able to tolerate salinity up to 3 %, where the degradation of crude oil was not inhibited (p [ 0.05). In artificial seawater, suspension of bacterial consortium culture was able to degrade 83.3 ± 3.00 % of crude oil within 8 weeks, which indi- cated the possibility of using consortium culture in sea- water. When tested in seawater, suspension of consortium culture managed to degrade 47.7 ± 1.53 % of crude oil in 8 weeks. In order to improve the performance of consor- tium culture, immobilisation of consortium culture onto SD and oil palm empty fruit bunch was successfully under- taken when formation of biofilm layers was observed under scanning electron microscope. Immobilising consortium culture onto oil palm empty fruit bunch and SD was shown to increase crude oil biodegradation to 68.7 ± 4.04 and 62.3 ± 5.51 % in 8 weeks, respectively. This study dem- onstrated immobilisation of consortium culture onto SD and oil palm empty fruit bunch can be utilised as ready-to- use seeds to improve and accelerate crude oil biodegrada- tion in seawater. Keywords Bacteria  Biodegradation  Biofilm  Carrier materials  Hydrocarbon  Petroleum wastes Introduction Seawater pollution by crude oil hydrocarbon is a serious international concern for it causes ecological damage to marine shorelines and having an adverse impact on fishery activities and public health (Vila et al. 2010). The main sources of seawater hydrocarbon pollution are crude oil offshore exploration and the use and transportation of crude oil products. Physicochemical methods used to remove hydrocarbon pollution are costly and limited in effectiveness (Lawniczak et al. 2010). Therefore, there is an increase tension to develop environmental-friendly and cost-effective method (Bao et al. 2012). At present, bio- remediation using microbial cells has gained popularity because microbes can synthesize a variety of enzymes to degrade an extensive range of hydrocarbons (Mahjoubi et al. 2013), easily regenerated, can be optimised and incorporated into other treatment plants and can be applied in situ or ex situ (ITOPF 2011). Numerous investigators have studied the use of hydro- carbon-degrading consortia isolated and enriched from polluted marine sediments (Mille et al. 1991) or from hypersaline environments such as salt marshes (Bertrand et al. 1993). In the present study, consortium culture (CC) with metal-resistant characteristic (Sannasi et al. 2009) will be tested under different salinity, artificial seawater and seawater to degrade crude oil hydrocarbon since crude oil contamination sites are frequently co-contaminated by W. Kok Kee (&)  H. Hazaimeh  S. A. Mutalib  S. Surif Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor D.E., Malaysia e-mail: anson_gulf@yahoo.co.uk P. S. Abdullah Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800 Nilai, N. Sembilan, Malaysia 123 Int. J. Environ. Sci. Technol. (2015) 12:2253–2262 DOI 10.1007/s13762-014-0619-7