Enhancement of Remediation Technologies with Biosurfactants - Biosurfactants: Research Trends and Applications - page 264

TABLE 10.2 (continued)
Summary of Biodegradation Studies Involving Biosurfactants

Biosurfactant Medium Microorganism Contaminant References

Rhamnolipid Liquid Consortium Diesel Vasefy and

Mulligan (2008)

Liquid Pseudomonas

strain

Crude oil, diesel Mehdi and Giti

(2008)

Surfactin Liquid Isolates Crude oil Li et al. (2006)

Rhamnolipid Soil Consortium Diesel Jalali and

Mulligan (2007)

Rhamnolipid Soil Luteibacter sp. Petroleum and heavy

metals

Zhang et al.
(2011)

Biosurfactant Sludge P. aeruginosa and

rhodococcus
consortium

Oil Cameotra and

Singh (2008)

Rhamnolipid Drill

cuttings

Consortium Oil Yan et al. (2011)

Rhamnolipid Wastewater P. aeruginosa Oil Yin et al. (2008)

Biosurfactant Water Sludge 4-Chlorophenol Usyal and

Turkman (2007)

Rhamnolipid Water Consortium PCE Hamidi and

Mulligan (2010)

Source: Adapted from Makkar and Rockne, 2003.
Note: All these studies showed a positive effect of the biosurfactant on biodegradation.

studies have involved rhamnolipids, although there are many that have been discov-
ered (Table 10.1). Other biosurfactants may be more effective, however, and therefore
more investigation is needed in the evaluation of other biosurfactants.
If the remediation can be performed in situ, production of the biosurfactants
could also be in situ. This would be technically feasible and cost-effective. Less labor
and transport would be required and the process would be ecologically acceptable.
Implementation and survival of pure cultures on sites would be difficult since they
would be outcompeted by indigenous microorganisms. However, strains of Bacillus
and Pseudomonas at hydrocarbon-contaminated sites have been determined to be
biosurfactant producers (Jennings and Tanner, 2000). Exploiting their presence may
be the best strategy. As the bioavailability of the contaminant also plays an important
factor in biodegradation, the role of biosurfactant production in the subsurface is not
known but could significantly enhance the natural attenuation process (Yong and
Mulligan, 2004). As the biosurfactants could influence the fate and transport of the
contaminants in the subsurface studies are clearly needed in this area.
Dissolution of mixtures of multicomponent NAPLs by surfactant is not well-
understood. Simple two- and three-component systems at most have been studied
to gain a basic understanding. Only a few studies have also been completed regard-
ing mixed organic and inorganic contamination. More research of more complex