lower phosphate concentration along with the addition of ethanol. Additionally, the
salinity of a specific medium is a critical part of biosurfactant production. For some
biosurfactant items, opposite perceptions are seen, which means not influenced by
fixations up to 10% (weight/volume) even if slight diminishments in the CMC were
distinguished (Kugler et al. 2015).
4.6.5 Growth Conditions
There are different growth conditions, such as pH, temperature, incubation time,
aeration, and agitation speed, that affect the biosurfactant production output. Pseudomonas putida MTCC produced a maximum of 2.5 gL
À1 of lipopeptide
biosurfactant at pH 8.0 (Kanna et al. 2014). At pH 6.8, biosynthesis from Actinomycetes nocardiopsis A17 was observed to be the highest, but the activity of
biosurfactant was still maintained at lower and higher pH (Chakraborty et al.
2015). Aeration and agitation speed also affect the production of biosurfactants.
Agitation speed affects oxygen molecules and the mass transfer efficiency of the
medium components, and incubation periods also affect biosurfactant production
(Yao et al. 2015). Thavasi et al. (2009) demonstrated that 4 days is the optimal
incubation period for Azotobacter chroococcum. The size of the inoculum is also
another critical factor that has a significant consequence in biosurfactant synthesis
(Nalini and Parthasarathi 2017).
4.7 Biosurfactant Extraction, Purification,
and Characterization
4.7.1 Biosurfactant Extraction
Downstream processing accounts for 70–80% of total production costs in many
biotechnological processes (Varjani et al. 2014). Different methods, such as
adsorption-desorption, solvent extractions, ion exchange, centrifugation, acid precipitation, and filtration, are known for their extraction. Several solvents, such as
chloroform, hexane, pentane, ethyl acetate, methanol, etc., are used for the extraction
of biosurfactants (Fig. 1.5).
4.7.2 Biosurfactant Purification
There are different biosurfactant purification techniques available, including thinlayer chromatography (TLC), dialysis, lyophilization, and isoelectric focusing (IEF).
In the TLC method by using chloroform:methanol:water (10:10:0.5 v/v/v) mixture, a
part of the crude biosurfactant is separated on a silica gel plate. Utilizing a developing solvent system with a different color developing reagent, such as ninhydrin, is
1 A Review on Production, Properties, and Applications of Microbial Surfactants as. . .
15
salinity of a specific medium is a critical part of biosurfactant production. For some
biosurfactant items, opposite perceptions are seen, which means not influenced by
fixations up to 10% (weight/volume) even if slight diminishments in the CMC were
distinguished (Kugler et al. 2015).
4.6.5 Growth Conditions
There are different growth conditions, such as pH, temperature, incubation time,
aeration, and agitation speed, that affect the biosurfactant production output. Pseudomonas putida MTCC produced a maximum of 2.5 gL
À1 of lipopeptide
biosurfactant at pH 8.0 (Kanna et al. 2014). At pH 6.8, biosynthesis from Actinomycetes nocardiopsis A17 was observed to be the highest, but the activity of
biosurfactant was still maintained at lower and higher pH (Chakraborty et al.
2015). Aeration and agitation speed also affect the production of biosurfactants.
Agitation speed affects oxygen molecules and the mass transfer efficiency of the
medium components, and incubation periods also affect biosurfactant production
(Yao et al. 2015). Thavasi et al. (2009) demonstrated that 4 days is the optimal
incubation period for Azotobacter chroococcum. The size of the inoculum is also
another critical factor that has a significant consequence in biosurfactant synthesis
(Nalini and Parthasarathi 2017).
4.7 Biosurfactant Extraction, Purification,
and Characterization
4.7.1 Biosurfactant Extraction
Downstream processing accounts for 70–80% of total production costs in many
biotechnological processes (Varjani et al. 2014). Different methods, such as
adsorption-desorption, solvent extractions, ion exchange, centrifugation, acid precipitation, and filtration, are known for their extraction. Several solvents, such as
chloroform, hexane, pentane, ethyl acetate, methanol, etc., are used for the extraction
of biosurfactants (Fig. 1.5).
4.7.2 Biosurfactant Purification
There are different biosurfactant purification techniques available, including thinlayer chromatography (TLC), dialysis, lyophilization, and isoelectric focusing (IEF).
In the TLC method by using chloroform:methanol:water (10:10:0.5 v/v/v) mixture, a
part of the crude biosurfactant is separated on a silica gel plate. Utilizing a developing solvent system with a different color developing reagent, such as ninhydrin, is
1 A Review on Production, Properties, and Applications of Microbial Surfactants as. . .
15