Biosurfactants and Bioemulsifiers from Marine Sources - Biosurfactants: Research Trends and Applications - page 139

microorganisms, but long-term medication may induce the development of resis-
tant strains (Rodrigues et al., 2007). However, antiadhesion results reported by
Rodrigues et al. (2006a,b) suggest an alternate way of using microbial BSs as
antiadhesive agent; in this process, the BSs used not necessarily have to be an
antimicrobial agent and that approach may prevent the antimicrobial resistance
development among the microbes involved in adhesion.
Another interesting example for the therapeutic application of BSs is sophoro-
lipids, a family of natural and easily chemoenzymatically modified microbial gly-
colipid, showed promising immune modulator activity in a rat model of sepsis.
Sophorolipid administration after the induction of intra-abdominal sepsis signifi-
cantly decreased the rat mortality in this model. This may be mediated in part by
decreased macrophage nitric oxide production and modulation of inflammatory
responses (Bluth et al., 2006).
Enhanced healing of full-thickness burn wounds using dirhamnolipid was
reported by Stipcevic et al. (2006). In this study, treatment of full-thickness burn
wounds with topical 0.1% dirhamnolipid accelerated the closure of wounds by 32%
within 21 days of the treatment as compared to control where no rhamnolipids used.
Dirhamnolipid was well tolerated by the animals (rat), which indicates the nontoxic-
ity toward mammalian cells. This study indicated the possible potential application
of dirhamnolipid in accelerating normal wound healing and perhaps in overcoming
defects associated with healing failure in chronic wounds. BSs isolated from marine
microbes may have similar properties, which requires further research. The earlier
results clearly indicate that evaluation of marine BSs for therapeutic applications
may bring more interesting properties into light and add more values to marine BSs.
Biosurfactants and nanotechnology : The biological synthesis of nanoparticles has
gained considerable attention in view of their exceptional biocompatibility and low
toxicity. The use of surfactants as nanoparticle stabilizing agents is an emerging field;
however, synthetic surfactants are not environmentally friendly. The application of BSs
as an alternate to synthetic surfactants for nanoparticle stabilization could be a green
ecofriendly approach. BS-mediated nanoparticle syntheses have been reported for
microbially produced rhamnolipids (Kumar et al., 2010) and sophorolipids (Kasture
et al., 2008) isolated from nonmarine sources. Synthesis of silver nanoparticles by gly-
colipid BS isolated from marine B. casei MSA19 was reported by Kiran et al. (2010b).
They used an in situ water-in-oil microemulsion phase for the particle synthesis. The
glycolipid BS was used as a particle-stabilizing agent by forming reverse micelles. The
silver nanoparticles synthesized in this study were uniform and stable for 2 months.
Therefore, the BS-mediated nanoparticle synthesis can be considered as “green” stabi-
lizer of nanoparticles and could be extended to other marine microbial BSs.
CONCLUSION
Although BSs have been the subject of intense investigation during the past few decades,
relatively small numbers of microorganisms and research output have focused on their
production from marine microorganisms. Nevertheless, some marine microbial com-
munities, including Acinetobacter , Arthrobacter , Pseudomonas , Halomonas , Bacillus ,