Characterization, Production, and Applications of Lipopeptides - Biosurfactants: Research Trends and Applications - page 164

Another species, Paenibacillus alvei (Najafi et al., 2011), was isolated from an
oil field. Biosurfactant production was optimized with central composite rotatable
design response surface methodology. The biosurfactant reduces the surface tension
to 35 mN/m. A glucose concentration of 13 g/L, temperature of 35°C, a 51 g/L total
salt concentration, and pH 6.9 were the optimal conditions.
A strain of B. amyloliquefaciens was isolated from crude oil (Sang-Cheol et al.,
2010). Lipopeptides of molecular mass of 1086.9 and 1491.2 m / z were determined.
The higher MW corresponds to fengycin B. However, as the structure differed from
fengycin A and B forms, it was designated as fengycin S. Due to its properties of
emulsification, it could be used for oil spills.
Rufino et al. (2012) produced a lipopeptide from a yeast Candida lipolytica .
A waste soybean oil residue was used as the substrate. The surface tension was
25 mN/m, and the CMC of the crude form was 0.03% and consisted of 50% protein,
20% lipid, and 8% carbohydrate.
Pseudomonas aeruginosa strains MTCC7815 and MTCC7812 were studied for
solubilization and metabolism of fluorene, pyrene, and phenanthrene (Bordolai and
Konwar, 2009). Pyrene and fluorene were solubilized by these two lipopeptide-
producing strains, which enhanced growth. The surface tension was reduced to
35 mN/M by these strains, and the CMC were 100 and 110 mg/L for MTCC7815 and
MTCC 7812, respectively. Previous studies (Bordolai and Konwar, 2008) showed
that these biosurfactants were very stable (pH 2.5-1) and up to 100°C. Crude oil-
saturated sand pack studies indicated that 50%-60% of the oil could be recovered
from room temperature to 90°C, indicating potential for enhanced oil recovery.
Glucose and glycerol were the best carbon sources.
Saimmai et al. (2013) isolated strains from mangrove sediments that produce
biosurfactants. Many pollutants such as hydrocarbons are found in the sediments,
and thus biosurfactant production could enhance the uptake of these pollutants
by the bacteria. They identified a strain of S. ruminantium CT2 that produced the
lipopeptide for the first time. It grew the best on molasses and could reduce the
surface tension to 25.5 mN/m with a CMC of 8 mg/L. Maximum production was
5 g/L. Ethyl acetate could be used to extract the biosurfactant from the broth. The
biosurfactant was characterized as a lipopeptide similar to surfactin. It showed
good pH and temperature stability and could enhance motor oil removal from
contaminated sand, ability to solubilize polycyclic aromatic hydrocarbons, and
antimicrobial activity.
PROPERTIES AND APPLICATIONS OF LIPOPEPTIDES
Surfactin addition improved the mechanical dewatering of peat by greater than 50%
at very low concentrations (0.0013 g/g wet peat) by altering the low characteris-
tics of the trapped water within the peat particles (Cooper et al., 1986). Surfactin
has also shown the ability to inhibit blood coagulation and protein denaturation,
to accelerate fibrinolysis, and to have antimyoplasmic properties (Vollenbroich
et al., 1997). Mycoplamata leads to respiratory inflammation, urogenital tract dis-
eases, and cofactors in the AIDS (Vollenbroich et al., 1997) pathogenesis. Antibiotic
therapy is not effective against mycoplasmata, but surfactin can cause leakage of the