Biosurfactants are potentially repl

Biosurfactants are potentially replacements for synthetic surfactants in several industrial
processes, such as lubrication, wetting, softening, fixing dyes, making emulsions, stabilizing
dispersions, foaming, preventing foaming, as well as in food, biomedical and pharmaceutical
industry, and bioremediation of organic- or inorganic-contaminated sites. Glycolipids and
lipopeptides are the most important biosurfactants (BS) for commercial purpose (Table 1).
Shete et al. (2006) [16] mapped the patents on biosurfactants and bioemulsifiers (255 patents
issued worldwide) showing high number of patents in the petroleum industry (33%), cosmet‐
ics (15%), antimicrobial agent and medicine (12%) and bioremediation (11%). Sophorolipids
(24%), surfactin (13%) and rhamnolipids (12%) represent a large portion of the patents,
however, this may be underestimated since many patents do not specify the producer
organism restricting to the specific use of the BS only.
Biodegradation - Life of Science 32
Biosurfactant class Microorganism Application
Glycolipids Rhamnolipids P. aeruginosa and P. putida Bioremediation
P. chlororaphis Biocontrol agent
Bacillus subtilis Antifungal agent
Renibacterium salmoninarum Bioremediation
Sophorolipids Candida bombicola and C. apicola Emulsifier, MEOR, alkane dissimilation
Trehalose lipidsRhodococcus spp. Bioremediation
Tsukamurella sp. and Arthrobacter sp.Antimicrobial agent
Mannosylerythr
itol lipids
Candida antartica Neuroreceptor antagonist, antimicrobial
agent
Kurtzmanomyces sp Biomedical application
Lipopeptides Surfactin Bacillus subtilis Antimicrobial agent, biomedical application
Lichenysin B. licheniformis Hemolytic and chelating agent
Table 1. Major types of biosurfactants.
Improvement of detection methods together with increased concerns with environmental
issues are pushing researchers and policymakers towards more environmentally friendly
solutions for waste management and replacements for non-biodegradable substances. Organic
aqueous wastes (e.g., pesticides), organic liquids, oils (e.g., petroleum-based) and organic
sludges or solids (e.g., paint-derived) are common environmental organic chemical hazards
and are source of soil and aquatic contaminations that are normally difficult to be removed.
Another commonly found environmental hazard are the heavy metals, such as lead, mercury,
chromium, iron, cadmium and copper, which are also linked to activities of our modern
society. The remediation of contaminated sites is usually performed via soil washing or in situ
flushing, in case of soil contamination, and bioremediation or use of dispersants, in case of
aquatic areas. Soil washing/flushing is heavily dependent on the solubility of the contaminants,
which can be very challenging when dealing with poorly soluble hazards. Hydrophobic
contaminants usually require use of detergents or dispersants, both in soil or aquatic environ‐
ment, and the process is often followed by their biodegradation. Heavy metal, however, cannot
be biodegraded and are converted to less toxic forms instead. Hence, the commonly found
combination of inorganic and organic contamination demands a complex remediation process.
High hydrophobicity and solid-water distribution ratios of some pollutants result in their
interaction with non-aqueous phases and soil organic matter. Those interactions reduce
dramatically the availability for microbial degradation, since bacteria preferentially degrade
chemicals that are dissolved in water [17].
Bioremediation is a process that aims the detoxification and degradation of toxic pollutants
through microbial assimilation or enzymatic transformation to less toxic compounds [18]. The
success of this process relies on the availability of microbes, accessibility of contaminants and
conduciveness of environment. A typical bioremediation process consists of application of
Biosurfactants: Production and Applications
http://dx.doi.org/10.5772/56144
33
nutrients (containing nitrogen and phosphorous), under controlled pH and water content,
together with an emulsifier and surface-active agents. Biostimulation is the bioremediation
based on the stimulation of naturally indigenous microbes by addition of nutrients directly to
the impacted site, whereas bioaugmentation is based on addition of specific microbes and
nutrients to the impacted site. Bioaugmentation has been subject of several reports including
use of genetically engineered microorganisms (reviewed in Gentry et al., 2004 [19]). Biostimu‐
lation success relies on microorganism targeting the pollutant as a primarily food source,
which is supported by available electron donors/acceptors and nutrients (reviewed in Smets
& Pritchard, 2003 [20]).
The bioavailability of a chemical in general is governed by physical-chemical processes such
as sorption and desorption, diffusion and dissolution. Microorganisms improve bioavailabil‐
ity of potential biodegradable nutrients by production of biosurfactants [21], and the success
of microbes in colonize a nutrient-restricted environment is often related to their capacity of
producing polymers with surfactant activity.
The best-studied biosurfactant are the glycolipids, which contain mono- or disaccharides
linked to long-chain aliphatic acids or hydroxyaliphatic acids. Rhamnolipids are better known
glycolipid class, which are normally produced as a mixture of congeners that varies in
composition according to the bacterium strain and medium components, which provides
specific properties to rhamnolipids derived from different isolates and production processes
[7]. This class of biosurfactant has been implied in several potential applications such as in
bioremediation, food industry, cosmetics and as an antimicrobial agent. Several reports have
been shown rhamnolipids to be efficient in chelating and remove/wash heavy metals, perhaps
due to the interaction between the polar glycosidic group with the metal ions. Whereas their
interaction with organic compounds increases their bioavailability or aids their mobilization
and removing in a washing treatment. Rhamnolipids have been shown to be effective in
reducing oil concentration in contaminated sandy soil [22] and their addition at relatively low
concentration (80 mg/L) to diesel/water system substantially increased biomass growth and
diesel degradation [23]. Interestingly, rhamnolipids combined with a pool of enzyme pro‐
duced by Penicillium simplicissimum enhanced the biodegradation of effluent with high fat
content from poultry processing plant, suggesting a synergistic interaction between biosur

Kết quả (Việt) 1:

Biosurfactants are potentially replacements for synthetic surfactants in several industrialprocesses, such as lubrication, wetting, softening, fixing dyes, making emulsions, stabilizingdispersions, foaming, preventing foaming, as well as in food, biomedical and pharmaceuticalindustry, and bioremediation of organic- or inorganic-contaminated sites. Glycolipids andlipopeptides are the most important biosurfactants (BS) for commercial purpose (Table 1).Shete et al. (2006) [16] mapped the patents on biosurfactants and bioemulsifiers (255 patentsissued worldwide) showing high number of patents in the petroleum industry (33%), cosmet‐ics (15%), antimicrobial agent and medicine (12%) and bioremediation (11%). Sophorolipids(24%), surfactin (13%) and rhamnolipids (12%) represent a large portion of the patents,however, this may be underestimated since many patents do not specify the producerorganism restricting to the specific use of the BS only.Biodegradation - Life of Science 32Biosurfactant class Microorganism ApplicationGlycolipids Rhamnolipids P. aeruginosa and P. putida BioremediationP. chlororaphis Biocontrol agentBacillus subtilis Antifungal agentRenibacterium salmoninarum BioremediationSophorolipids Candida bombicola and C. apicola Emulsifier, MEOR, alkane dissimilationTrehalose lipidsRhodococcus spp. BioremediationTsukamurella sp. and Arthrobacter sp.Antimicrobial agentMannosylerythritol lipidsCandida antartica Neuroreceptor antagonist, antimicrobialagentKurtzmanomyces sp Biomedical applicationLipopeptides Surfactin Bacillus subtilis Antimicrobial agent, biomedical applicationLichenysin B. licheniformis Hemolytic and chelating agentTable 1. Major types of biosurfactants.Improvement of detection methods together with increased concerns with environmentalissues are pushing researchers and policymakers towards more environmentally friendlysolutions for waste management and replacements for non-biodegradable substances. Organicaqueous wastes (e.g., pesticides), organic liquids, oils (e.g., petroleum-based) and organicsludges or solids (e.g., paint-derived) are common environmental organic chemical hazardsand are source of soil and aquatic contaminations that are normally difficult to be removed.Another commonly found environmental hazard are the heavy metals, such as lead, mercury,chromium, iron, cadmium and copper, which are also linked to activities of our modernsociety. The remediation of contaminated sites is usually performed via soil washing or in situflushing, in case of soil contamination, and bioremediation or use of dispersants, in case ofaquatic areas. Soil washing/flushing is heavily dependent on the solubility of the contaminants,which can be very challenging when dealing with poorly soluble hazards. Hydrophobiccontaminants usually require use of detergents or dispersants, both in soil or aquatic environ‐ment, and the process is often followed by their biodegradation. Heavy metal, however, cannotbe biodegraded and are converted to less toxic forms instead. Hence, the commonly foundcombination of inorganic and organic contamination demands a complex remediation process.High hydrophobicity and solid-water distribution ratios of some pollutants result in theirinteraction with non-aqueous phases and soil organic matter. Those interactions reducedramatically the availability for microbial degradation, since bacteria preferentially degradechemicals that are dissolved in water [17].Bioremediation is a process that aims the detoxification and degradation of toxic pollutantsthrough microbial assimilation or enzymatic transformation to less toxic compounds [18]. Thesuccess of this process relies on the availability of microbes, accessibility of contaminants andconduciveness of environment. A typical bioremediation process consists of application ofBiosurfactants: Production and Applicationshttp://dx.doi.org/10.5772/5614433nutrients (containing nitrogen and phosphorous), under controlled pH and water content,together with an emulsifier and surface-active agents. Biostimulation is the bioremediationbased on the stimulation of naturally indigenous microbes by addition of nutrients directly tothe impacted site, whereas bioaugmentation is based on addition of specific microbes andnutrients to the impacted site. Bioaugmentation has been subject of several reports includinguse of genetically engineered microorganisms (reviewed in Gentry et al., 2004 [19]). Biostimu‐lation success relies on microorganism targeting the pollutant as a primarily food source,which is supported by available electron donors/acceptors and nutrients (reviewed in Smets& Pritchard, 2003 [20]).The bioavailability of a chemical in general is governed by physical-chemical processes suchas sorption and desorption, diffusion and dissolution. Microorganisms improve bioavailabil‐ity of potential biodegradable nutrients by production of biosurfactants [21], and the successof microbes in colonize a nutrient-restricted environment is often related to their capacity ofproducing polymers with surfactant activity.The best-studied biosurfactant are the glycolipids, which contain mono- or disaccharideslinked to long-chain aliphatic acids or hydroxyaliphatic acids. Rhamnolipids are better knownglycolipid class, which are normally produced as a mixture of congeners that varies incomposition according to the bacterium strain and medium components, which providesspecific properties to rhamnolipids derived from different isolates and production processes[7]. This class of biosurfactant has been implied in several potential applications such as inbioremediation, food industry, cosmetics and as an antimicrobial agent. Several reports havebeen shown rhamnolipids to be efficient in chelating and remove/wash heavy metals, perhapsdo sự tương tác giữa nhóm glycosidic cực với các ion kim loại. Trong khi đó của họtương tác với các hợp chất hữu cơ làm tăng khả dụng sinh học của họ hoặc hỗ trợ vận động của họvà loại bỏ trong một điều trị rửa. Rhamnolipids đã được chứng minh là có hiệu quả tronggiảm dầu tập trung tại ô nhiễm đất cát [22] và của họ bổ sung tại tương đối thấptập trung (80 mg/L) để hệ thống động cơ diesel/nước đáng kể tăng sự phát triển nhiên liệu sinh học vàđộng cơ diesel các suy thoái [23]. Điều thú vị, rhamnolipids kết hợp với một hồ bơi của enzym pro‐duced bởi Penicillium simplicissimum nâng cao phân nước thải với cao chất béonội dung từ chăn nuôi gia cầm nhà máy chế biến, cho thấy một sự tương tác hiệp đồng giữa biosur