Rhizodegradation of Hydrocarbon from Oily Sludge

Rhizoremediation involves the use of plant growth promoting rhizobacteria (PGPR) to remove organic pollutants from terrestrial environment. The main objective of this study was to evaluate the efficiency of rhizoremediation through inoculation of hydrocarbon degrading bacterial strains with and without nutrients in the rhizosphere sporadically become contaminated with oily sludge. Bacterial strains viz. Bacillus cereus (Acc KF859972), Bacillus altitudinis (Acc KF859970), comamonas (Acc KF859971) and Stenotrophomonas maltophilia (Acc KF859973) were isolated from various oily waste pits of oil fields. Autoclaved soil was treated with oily sludge at 7:3 ratio and Alfalfa plant was inoculated with individual plant growth promoting rhizobacteria (PGPR) with and without diammonium phosphate and ammonium nitrate. The different saturates and total hydrocarbon was extracted by Soxhelt extraction and was analyzed by GC-FID at 0, 5 and 10 d of incubation. The inoculation 30% sludge with B. altitudinis accelerated the rate of degradation of n-alkanes and some methyl branched than un-inoculated soils. Oily sludge inoculated with B. altitudinis indicated that more than 80% of hydrocarbons were degraded at day 5 of incubation. No further degradation was observed till the end of the incubation period. B. altitudinis is capable of degrading straight chain hydrocarbons rapidly than any other strains. Alfalfa is a N-symbiotic plant and increased nutrient content under the rhizosphere promote degradation of n-alkanes. All other bacterial strains also showed significant interaction with alfalfa for the biodegradation of oily sludge but the rate of degradation remained slow than with B. altitudinis. Inoculation with B. altitudinis accelerated the rehabilitation process and within 5 days the rehabilitation occurs. Citation: Bano A, Shahzad A, Siddiqui S (2015) Rhizodegradation of Hydrocarbon from Oily Sludge. J Bioremed Biodeg 6: 289. doi:10.4172/21556199.1000289 Volume 6 • Issue 3 • 1000289 J Bioremed Biodeg ISSN: 2155-6199 JBRBD, an open access journal Page 2 of 11 rehabilitation process of degradation of oily sludge is more rapid than either through bioremediation or phytoremediation. Pradhan et al. [15] reported that the degradation of poly aromatic hydrocarbons (PAHs) were greater in soil where switchgrass (Panicumvirgatum) and little bluestem grass (Schizachyriumscoparium) were grown. They found that around 57 and 47% of PAHs were degraded than uncontaminated soils. Omotayo et al. [16] reported that inoculation of 50 mg of crude oil per g of soil with consortium of hydrocarbon degrading bacteria such as Arthrobacter sp., Bacillus pumilus, Bacillus sphaericus and Serratiamarcescens and perennial rye grass has increased the rate of degradation of hydrocarbons and around 87.7% of total hydrocarbons were degraded from the soil at 45 days of incubation. The study was aimed to enhance the natural rehabilitation process of oily sludge contaminated soils inoculated with plant growth promoting bacteria isolated from the host oily sludge and to understand the role of alfalfa on the degradation of hydrocarbons in oily sludge contaminated soils. Materials and Method Geology and samples description from potwar plateau The Kohat-Potwar Plaeatu is situated in the south of the Himalaya and Karakorum Mountains. It is located between latitude 32° and 34°N and longitude 70° and 74°E. It is bounded by the Salt Range and Trans-Indus Range in the south, Kala chitta Range in the north. The Plateau opens up towards Jehlum River in the east. The west of the Plateau is bounded with Kurram-Parachinar Range [17]. Potwar plateau is an oil prone area. Up till now 40 structures have been drilled for oil exploration among which 10 structures have a potential of oil production [18]. The oily sludge from three oil fields within Potwar plateau were selected because of the difference in the reservoir depth, geological formation and age, API gravity, extent of degradation and crude oil composition (Table 1).