Table 1.

An overview of recent studies on biosurfactant-assisted bioremediation

Type of biosurfactant	Pollutant	Relevant bioremediator	Established effect	Removal efficiency	Reference
Rhamnolipids	Phenanthrene	Sphingomonas sp. monoculture	Positive—solublization	99 % after 10 days compared to 84 % without biosurfactant (IC—10 g/l)	Pei et al. (2010)
Rhamnolipids	Anthracene	Sphingomonas sp. and Pseudomonas sp. monocultures	Positive—solubilization	52 % after 18 days compared to 32 % without biosurfactant for Pseudomonas (IC—25 mg/l)	Cui et al. (2008)
Rhamnolipids (Mono-rhamnolipid)	Hexadecane	Candida tropicalis monoculture	Positive/negative	93 % after 4 days compared to 78 % without biosurfactants (IC—500 mg/l)	Zeng et al. (2011)
Rhamnolipids, emulsan and indigenous biosurfactants	Pyrene	Pseudomonas fluorescens monoculture	Positive/negative	98 % after 10 days compared to 91 % without emulsan (IC—50 mg/l)	Husain (2008)
Rhamnolipids	Polycyclic aromatic hydrocarbons	Alfalfa + arbuscular mycorrhizal fungi + microbial consortium of PAH degraders	Positive—solubilization	61 % after 90 days compared to 17 % with only phytoremediation (IC—12.85 g/kg of soil)	Zhang et al. (2010)
Rhamnolipids (Mono-rhamnolipid)	Phenol	Candida tropicalis monoculture	Positive—enhanced cell growth	99 % after 30 h compared to 87 % without biosurfactant (IC—500 mg/l)	Liu et al. (2010)
Rhamnolipids	Crude oil hydrocarbons	Autochthonous marine microflora	Positive/no effect	Up to 25 % for alkanes after 5 days with biosurfactant alone and 59 % when used with nutrients (IC—823 mg/l)	McKew et al. (2007)
Rhamnolipids	Crude oil hydrocarbons	Autochthonous marine microflora	Positive—increased bioavailability	96 % for C19–C34 alkane fraction after 18 days compared to 10 % without amendment (IC—5 g/l)	Nikolopoulou and Kalogerakis (2008)
Rhamnolipids	Phenanthrene	Sphingomonas sp. and Paenibacillus sp. monocultures	Negative	23 % after 8 days compared to 74 % without biosurfactant	Shin et al. (2005)
Rhamnolipids	Phenanthrene	Pseudomonas putida ATCC 17484 monoculture	Positive/no effect/negative	91 % after 10 days compared to 68 % without biosurfactant (IC—approx. 500 mg/kg of soil)	Gottfried et al. (2010)
Rhamnolipids	Phenanthrene	Sphingomonas sp. monoculture	Positive—mobilization	47 % after 70 days compared to 36 % without biosurfactant (IC—approx. 200 mg/kg of soil)	Shin et al. (2006)
Rhamnolipids	Diesel oil and biodiesel blends	Microbial consortium	Positive/no effect	77 % after 7 days compared to 58 % without biosurfactants for blends (IC—approx. 15 g/l)	Owsianiak et al. (2009a, b)
Rhamnolipids	Phenanthrene and pyrene	Ryegrass	Positive—increased uptake	Uptake of phenanthrene and pyrene into ryegrass roots was at 435 and 380 mg/kg, respectively, compared to 77 and 158 mg/kg without biosurfactant	Zhu and Zhang (2008)
Rhamnolipids	Cadmium	Vibrio fischeri, Pseudomonas fluorescens, P. aeruginosa, Escherichia coli and Bacillus subtilis monoluctures	Positive/negative	Rhamnolipids were toxic at higher concentrations (>45 mg/l), however at 40 mg/l their presence inhibited the toxicity of cadmium ions by reducing their bioavailability	Bondarenko et al. (2010)
Rhamnolipids and organic acids	Copper	Indian mustard and ryegrass	Positive—mobilization	Application of rhamnolipids and other amendments notably increased copper uptake by both plants	Johnson et al. (2009)
Sophorolipid	Hydrocarbon mixture	Autochthonous soil microflora	Positive—solubilization and mobilization	Respectively: 95 % after 2 days, 97 % after 6 days and 85 % after 6 days (IC- 6 mg/g of soil)	Kang et al. 2010
Not specified	p,p'-DDE	Cucurbita subspecies	Positive/negative	Biosurfactant amendment enhanced p,p′-DDE accumulation, however a 60 % biomass reduction was observed for ovifera subspecies	White et al. (2006)
Not specified	Petrochemical oily sludge	Mixed bacterial cultures	Positive—potential solubilization	91 % of the aliphatic fraction and 52 % of the aromatic fraction after 40 days	Cerqueira et al. (2011)
Not specified	Diesel oil hydrocarbons	Autochthonous soil microflora	Positive/no effect	77 % of aliphatic hydrocarbons after 15 days compared to 9 % without biosurfactant (IC—450 mg/l)	Martins et al. (2009)
Not specified	Pyrene	Bacillus subtilis and Pseudomonas aeruginosa monocultures	Positive—solubilization	48 % for Bacillus and 32 % for Pseudomonas after 4 days	Das and Mukherjee (2007)

IC initial concentration at the start of the experiment