Hydrocarbon biodegradation in oxygen-limited sequential batch reactors by consortium from weathered, oil-contaminated soil

Abstract

We studied the use of sequential batch reactors under oxygen limitation to improve and maintain consortium ability to biodegrade hydrocarbons. Air-agitated tubular reactors (2.5 L) were operated for 20 sequential 21-day cycles. Maya crude oil-paraffin mixture (13,000 mg/L) was used as the sole carbon source. The reactors were inoculated with a consortium from the rhizosphere of Cyperus laxus, a native plant that grows naturally in weathered, contaminated soil. Oxygen limitation was induced in the tubular reactor by maintaining low oxygen transfer coefficients (k(L)a < 20.6 h(-1)). The extent and biodegradation rates increased significantly up to the fourth cycle, maintaining values of about 66.33% and 460 mg x L(-1) x d(-1), respectively. Thereafter, sequential batch reactor operation exhibited a pattern with a constant general trend of biodegradation. The effect of oxygen limitation on consortium activity led to a low biomass yield and non-soluble metabolite (0.45 g SS/g hydrocarbons consumed). The average number of hydrocarbon-degrading microorganisms increased from 6.5 x 10(7) (cycles 1-3) to 2.2 x 10(8) (cycles 4-20). Five bacterial strains were identified: Achromobacter (Alcaligenes) xylosoxidans, Bacillus cereus, Bacillus subtilis, Brevibacterium luteum, and Pseudomonas pseudoalcaligenes. Asphaltene-free total petroleum hydrocarbons, extracted from a weathered, contaminated soil, were also biodegraded (97.1 mg x L(-1) x d(-1)) and mineralized (210.48 mg CO2 x L(-1) x d(-1)) by the enriched consortium without inhibition. Our results indicate that sequential batch reactors under oxygen limitation can be used to produce consortia with high and constant biodegradation ability for industrial applications of bioremediation.

Kinetics of biodegradation of diesel fuel by enriched microbial consortia from polluted soils

“…The isolation of these species is not surprising due to their frequency in contaminated soils (Barathi and Vasudevan 2001;Ueno et al 2007). All of the other species found in the consortia have been shown to degrade hydrocarbons (Chaineau et al 1999;Lafortune et al 2009;Medina-Moreno et al 2005;Nikakhtari et al 2009;Owsianiak et al 2009;Rahman et al 2002).…”

Photoprotection and the Photophysics of Acylated Anthocyanins

“…Moreover, Kim and Jaffé26 reported the capacity of facultative Ralstonia picketii PKO1 to degrade toluene, whereas Juhas et al 27 showed the ability of Pseudomonas aeruginosa and Burkholderia cepacia to form mixed biofilms and hold intercellular communication. Furthermore, the strain AR‐46 of Acinetobacter haemolyticus has been reported to degrade n‐hexadecane28 and Achromobacter xylosoxidans was able to grow on crude oil under oxygen‐limiting conditions 29…”

The Role of Indigenous Microorganisms in the Biodegradation of Naturally Occurring Petroleum, the Reduction of Iron, and the Mobilization of Arsenite from West Bengal Aquifer Sediments

“…However, certain microbes present within WB8 and WB13 have previously been isolated from petroleum‐related environments: Pseudomonas pseudoalcaligenes , or more generally Pseudomonas spp. (Whyte et al, 1997; Leahy and Colwell, 1990; Medina‐Moreno et al, 2005); an uncultured bacterium clone, PL‐10B5, from production waters within a low‐temperature, biodegraded oil reservoir (Grabowski et al, 2005); and Acinetobacter spp. (Leahy and Colwell, 1990; Margesin et al, 2003).…”