Biosurfactants and Bioemulsifiers from Marine Sources - Biosurfactants: Research Trends and Applications - page 125

5 Biosurfactants and

Bioemulsifiers from
Marine Sources

Rengathavasi Thavasi and Ibrahim M. Banat

CONTENTS
Introduction ............................................................................................................ 125
Marine Biosurfactants ............................................................................................ 126
Areas of Potential Applications of Marine Biosurfactants .................................... 134
Conclusion ............................................................................................................. 139
Acknowledgment ................................................................................................... 140
References .............................................................................................................. 140

INTRODUCTION
Marine microbes are known for their many novel extra- and intracellular products such
as antibiotics, enzymes, biopolymers, pigments, and toxins. Reports suggest that so far
more than 10,000 metabolites with broad-spectrum biological activities and interest-
ing medicinal properties have been isolated from marine microbes (Kelecom, 2002).
However, due to the enormity of the marine biosphere, most of the marine microbial
worlds remain unexplored. It has been estimated that <0.1% of marine microbial world
has been explored or investigated (Ramaiah, 2005). Among various marine bioactive
compounds, microbial biosurfactants (BSs) are of great importance due to their struc-
tural and functional diversity and industrial applications (Banat et al., 1991; Banat,
1995a,b; Rodrigues et al., 2006a). Marine microbial BSs are such metabolites with
many interesting properties. BSs are basically amphiphilic surface active agents pro-
duced by bacteria, fungi, and actinomycetes. They belong to various classes including
glycolipids, glycolipoproteins, glycopeptides, lipopeptides, lipoproteins, fatty acids,
phospholipids, neutral lipids, lipopolysaccharides (Banat et al., 2010), and glycoglyc-
erolipids (Wicke et al., 2000). The properties/applications of BSs include detergency,
emulsification, foaming, dispersion, wetting, penetrating, thickening, microbial growth
enhancement (e.g., oil-degrading bacteria), antimicrobial agents, metal sequestering,
and resource recovering (oil recovery). These interesting properties allow BSs to
have the ability to replace some of the most versatile chemical surfactants that are
now in practice. In addition, BSs are promising natural surfactants that offer several
advantages over chemically synthesized surfactants, such as in situ production using

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