Surfactant‐enhanced biodegradation of high molecular weight polycyclic aromatic hydrocarbons by Stenotrophomonas maltophilia

Abstract

Abstract:The objectives of this study were to isolate and evaluate microorganisms with the ability to degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) in the presence of synthetic surfactants. Stenotrophomonas maltophilia VUN 10,010, isolated from PAHcontaminated soil, utilized pyrene as a sole carbon and energy source and also degraded other high molecular weight PAHs containing up to seven benzene rings. Various synthetic surfactants were tested for their ability to improve the PAH degradation rate of strain VUN 10,010. Anionic and cationic surfactants were highly toxic to this strain, and the Tween series was used as a growth substrate. Five nonionic surfactants (Brij 35, Igepal CA-630, Triton X-100, Tergitol NP-10, and Tyloxapol) were not utilized by, and were less toxic to, strain VUN 10,010. MSR and log K m values were determined for fluoranthene, pyrene, and benzo[a]pyrene in the presence of these nonionic surfactants and their apparent solubility was increased by a minimum of 250-fold in the presence of 10 g L −1 of all surfactants. The rate of pyrene degradation by strain VUN 10,010 was enhanced by the addition of four of the nonionic surfactants (5-10 g L −1 ); however, 5 g L −1 Igepal CA-630 inhibited pyrene degradation and microbial growth. The specific growth rate of VUN 10,010 on pyrene was increased by 67% in the presence of 10 g L −1 Brij 35 or Tergitol NP-10. The addition of Brij 35 and Tergitol NP-10 to media containing a single high molecular weight PAH (four and five benzene rings) as the sole carbon source increased the maximum specific PAH degradation rate and decreased the lag period normally seen for PAH degradation. The addition of Tergitol NP-10 to VUN 10,010 cultures which contained a PAH mixture (three to seven benzene rings) substantially improved the overall degradation rate of each PAH and increased the specific growth rate of VUN 10,010 by 30%. Evaluation of the use of VUN 10,010 for degrading high molecular weight PAHs in leachates from surfactantflushed, weathered, PAH-contaminated sites is warranted.

Bioremediation of naphthalene in water by Sphingomonas paucimobilis using new biodegradable surfactants based on poly (ɛ-caprolactone)

“…In accordance with these results, there are different cases in the literature where the use of surfactants, mainly non-ionic, above the critical micelle concentration (CMC) enhanced the biodegradation efficiency (Makkar and Rockne, 2003;Volkering et al, 1995;Boonchan et al, 1998) or just diminished the extent of their biodegradation (Guha et al, 1998). In other cases, surfactants in the micellar phase inhibited the biodegradation of organic contaminants (Laha and Luthy, 1992).…”

“…The species involved include Rhodococcus sp. (Walter et al, 1991), Burkholderia cepacia (Juhasz et al, 1997), Pseudomonas (Juhasz et al, 1996;Johnsen et al, 2005), Stenotrophomonas maltophilia (Boonchan et al, 1998), Mycobacterium sp. (Bouchez et al, 1995), Alcaligenes denitrificans (Weissenfels et al, 1990), and Sphingomonas paucimobilis (Mueller et al, 1990;Ye et al, 1996).…”

Stenotrophomonas acidaminiphila sp. nov., a strictly aerobic bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

“…Stenotrophomonas species are common inhabitants of a wide variety of natural and artificial environments such as water, sediments, plant rhizospheres, corroded metal surfaces, waste-gas biofilters, aquaculture tanks, oilfields, sewage and anaerobic reactors (Aznar et al, 1992 ;Boonchan et al, 1998 ;Borowicz et al, 1995 ;Britz et al, 1994 ;Finkmann et al, 2000 ;Hauben et al, 1999 ;Juhnke et al, 1987 ;Lambert et al, 1990 ;Leifert & Waites, 1992 ;Wallace et al, 1994 ;Wilkinson et al, 1994) and can be opportunistic human pathogens (Drancourt et al, 1997 ;Denton & Kerr, 1998).…”

Influence of Diphenyloxide Disulfonate Surfactants on Biodegradation of Hydrocarbons

“…Vis-a-vis, the potential for surfactants to increase the apparent aqueous solubility of hydrophobic compounds has led to their being considered as a means of improving contaminant accessibility for microorganisms. The influence of surfactants on biodegradation of HCs has continued to be a stimulating topic of research and discussion (Rouse et al, 1994;Köhler et al, 1994;Churchill et al, 1995;Liu et al, 1995;Volkering et al, 1995;Deschenes et al, 1995;Jahan et al, 1997;Tiehm et al, 1997;Boonchan et al, 1998). Surfactants, or surface-active agents, are amphipathic molecules consisting of a hydrophilic polar head and a hydrophobic nonpolar tail .…”