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Biosurfactant Production by Bacillus salmalaya for Lubricating Oil Solubilization and Biodegradation.

Dadrasnia A, Ismail S - Int J Environ Res Public Health (2015)

Bottom Line: The biosurfactant exhibited a high emulsification index and a positive result in the drop collapse test, with the results demonstrating the wetting activity of the biosurfactant and its potential to produce surface-active molecules.Furthermore, the biosurfactant demonstrated high stability at different ranges of salinity, pH, and temperature.Overall, the results indicated the potential use of B. salmalaya 139SI in environmental remediation processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biohealth Science, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. are.dadrasnia@gmail.com.

ABSTRACT
This study investigated the capability of a biosurfactant produced by a novel strain of Bacillus salmalaya to enhance the biodegradation rates and bioavailability of organic contaminants. The biosurfactant produced by cultured strain 139SI showed high physicochemical properties and surface activity in the selected medium. The biosurfactant exhibited a high emulsification index and a positive result in the drop collapse test, with the results demonstrating the wetting activity of the biosurfactant and its potential to produce surface-active molecules. Strain 139SI can significantly reduce the surface tension (ST) from 70.5 to 27 mN/m, with a critical micelle concentration of 0.4%. Moreover, lubricating oil at 2% (v/v) was degraded on Day 20 (71.5). Furthermore, the biosurfactant demonstrated high stability at different ranges of salinity, pH, and temperature. Overall, the results indicated the potential use of B. salmalaya 139SI in environmental remediation processes.

No MeSH data available.


Related in: MedlinePlus

Influence of NaCl (a), NaH2PO4 (b) and (NH4)2SO4 (c) on ST reduction (%).
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ijerph-12-09848-f004: Influence of NaCl (a), NaH2PO4 (b) and (NH4)2SO4 (c) on ST reduction (%).

Mentions: The effect of different carbon sources on ST was evaluated using 1% (v/v) olive, sunflower, transformer, glycerol, and vegetable oils. As shown in Figure 3C, a significant reduction in ST was observed with particular carbon sources. The lowest and highest ST reduction rates were found for the transformer and sunflower oils, with values of 33.5 and 71.1%, respectively (Figure 3C). Moreover, ST decreased with olive, vegetable, and glycerol oils, to 59.6, 57.3, and 48.6%, respectively. This result is in contrast with that of Zhang et al. [28] who reported the ability of P. aeruginosa to produce a biosurfactant in 30 g/L glycerol compared with paraffin and vegetable oil. In the present study, the reduction of ST in glycerol was less than that in the other carbon sources, which may be ascribed to the different bacterial genera used, and the various optimal pH and temperature values for biosurfactant production. The effects of salt and N and P concentrations on biosurfactant production were also assessed. Given the relatively high salinity in oil refineries, halophilic bacteria should be used during oil recovery. N and P concentrations and the nutrient formulation are important parameters to ensure rapid bacterial growth and biosurfactant production. Therefore, the possibility of biosurfactant production depends on the complex structure of the biosurfactant itself and on the concentrations of salts, N, and P. The results illustrated that the percentage of ST reduction was enhanced when the concentration of NaH2PO4 as a source of P increased to 15 g/L (Figure 4A); this finding indicated the positive effect of P on biosurfactant production. The maximum ST reduction (63.91%) was observed when 15 g/L NaH2PO4 and 40 g/L NaCl were added; in contrast, the percentage of ST reduction decreased to 45.9% with the addition of 60 g/L NaCl and 15 g/L NaH2PO4. This result is in very close agreement with the findings of Huszcza and Burczyk [29], who reported that the biosurfactant activity produced by B. coagulans was enhanced with the addition of salts. In addition, the maximum activity of the biosurfactant produced by B. subtilis was achieved with the addition of 15% NaCl [30]. The current results also indicated that B. salmalaya can grow under conditions of high salinity. The highest percentage of ST reduction (53.3%) with the simultaneous application of NaCl and (NH4)2PO4 was observed at concentrations of 40 and 1 g/L, respectively (Figure 4B). As shown in Figure 4C, to decrease ST, the optimal concentration of NaH2PO4 was 15 g/L without the addition of (NH4)2PO4. These results showed the inhibiting effect of low and high concentrations of N, P, and salts on the biological activities of strain 139SI. However, the lowest supernatant ST reduction (28.5%) was observed when the concentrations of NaCl, NaH2PO4, and (NH4)2PO4 were increased to 60, 7.5, and 2 g/L, respectively. Thus, increasing the concentration of NaCl and (NH4)2PO4 caused a decrease in biosurfactant production.


Biosurfactant Production by Bacillus salmalaya for Lubricating Oil Solubilization and Biodegradation.

Dadrasnia A, Ismail S - Int J Environ Res Public Health (2015)

Influence of NaCl (a), NaH2PO4 (b) and (NH4)2SO4 (c) on ST reduction (%).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555315&req=5

ijerph-12-09848-f004: Influence of NaCl (a), NaH2PO4 (b) and (NH4)2SO4 (c) on ST reduction (%).
Mentions: The effect of different carbon sources on ST was evaluated using 1% (v/v) olive, sunflower, transformer, glycerol, and vegetable oils. As shown in Figure 3C, a significant reduction in ST was observed with particular carbon sources. The lowest and highest ST reduction rates were found for the transformer and sunflower oils, with values of 33.5 and 71.1%, respectively (Figure 3C). Moreover, ST decreased with olive, vegetable, and glycerol oils, to 59.6, 57.3, and 48.6%, respectively. This result is in contrast with that of Zhang et al. [28] who reported the ability of P. aeruginosa to produce a biosurfactant in 30 g/L glycerol compared with paraffin and vegetable oil. In the present study, the reduction of ST in glycerol was less than that in the other carbon sources, which may be ascribed to the different bacterial genera used, and the various optimal pH and temperature values for biosurfactant production. The effects of salt and N and P concentrations on biosurfactant production were also assessed. Given the relatively high salinity in oil refineries, halophilic bacteria should be used during oil recovery. N and P concentrations and the nutrient formulation are important parameters to ensure rapid bacterial growth and biosurfactant production. Therefore, the possibility of biosurfactant production depends on the complex structure of the biosurfactant itself and on the concentrations of salts, N, and P. The results illustrated that the percentage of ST reduction was enhanced when the concentration of NaH2PO4 as a source of P increased to 15 g/L (Figure 4A); this finding indicated the positive effect of P on biosurfactant production. The maximum ST reduction (63.91%) was observed when 15 g/L NaH2PO4 and 40 g/L NaCl were added; in contrast, the percentage of ST reduction decreased to 45.9% with the addition of 60 g/L NaCl and 15 g/L NaH2PO4. This result is in very close agreement with the findings of Huszcza and Burczyk [29], who reported that the biosurfactant activity produced by B. coagulans was enhanced with the addition of salts. In addition, the maximum activity of the biosurfactant produced by B. subtilis was achieved with the addition of 15% NaCl [30]. The current results also indicated that B. salmalaya can grow under conditions of high salinity. The highest percentage of ST reduction (53.3%) with the simultaneous application of NaCl and (NH4)2PO4 was observed at concentrations of 40 and 1 g/L, respectively (Figure 4B). As shown in Figure 4C, to decrease ST, the optimal concentration of NaH2PO4 was 15 g/L without the addition of (NH4)2PO4. These results showed the inhibiting effect of low and high concentrations of N, P, and salts on the biological activities of strain 139SI. However, the lowest supernatant ST reduction (28.5%) was observed when the concentrations of NaCl, NaH2PO4, and (NH4)2PO4 were increased to 60, 7.5, and 2 g/L, respectively. Thus, increasing the concentration of NaCl and (NH4)2PO4 caused a decrease in biosurfactant production.

Bottom Line: The biosurfactant exhibited a high emulsification index and a positive result in the drop collapse test, with the results demonstrating the wetting activity of the biosurfactant and its potential to produce surface-active molecules.Furthermore, the biosurfactant demonstrated high stability at different ranges of salinity, pH, and temperature.Overall, the results indicated the potential use of B. salmalaya 139SI in environmental remediation processes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biohealth Science, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. are.dadrasnia@gmail.com.

ABSTRACT
This study investigated the capability of a biosurfactant produced by a novel strain of Bacillus salmalaya to enhance the biodegradation rates and bioavailability of organic contaminants. The biosurfactant produced by cultured strain 139SI showed high physicochemical properties and surface activity in the selected medium. The biosurfactant exhibited a high emulsification index and a positive result in the drop collapse test, with the results demonstrating the wetting activity of the biosurfactant and its potential to produce surface-active molecules. Strain 139SI can significantly reduce the surface tension (ST) from 70.5 to 27 mN/m, with a critical micelle concentration of 0.4%. Moreover, lubricating oil at 2% (v/v) was degraded on Day 20 (71.5). Furthermore, the biosurfactant demonstrated high stability at different ranges of salinity, pH, and temperature. Overall, the results indicated the potential use of B. salmalaya 139SI in environmental remediation processes.

No MeSH data available.


Related in: MedlinePlus