<abstract xmlns="http://www.w3.org/1999/xhtml"><p>This work aimed to optimize carbon and nitrogen sources for the growth of <italic>Enterobacter cloacae</italic> B14 and its biosurfactant (BS) production via One-Variable-At-a-Time (OVAT) method. The BS stability under a range of pH and temperatures was assessed. Antimicrobial activity against Gram-positive and Gram-negative pathogens was determined by the agar well diffusion method. The results showed that the optimum carbon and nitrogen sources for BS production were maltose and yeast extract, respectively, with a maximum BS yield of (39.8 ± 5.2) mg BS/g biomass. The highest emulsification activity (E24) was 79%, which is significantly higher than in the previous studies. We found that B14 BS can withstand a wide range of pH values from 2 to10. It could also function under a range of temperatures from 30–37°C. Thin Layer Chromatography (TLC) and Fourier Transform Infrared Spectrometry (FTIR) analysis confirmed that B14 BS is a glycolipid-like compound, which is rarely found in <italic>Enterobacter</italic> spp. Cell-free broth showed inhibition against various pathogens, preferable to Gram-positive ones. It had better antimicrobial activity against <italic>Bacillus subtilis</italic> than a commonly-used antibiotic, tetracycline. Furthermore, B14 broth could inhibit the growth of a tetracycline-resistant <italic>Serratia marcescens</italic>. Our results showed promising B14 BS applications not only for bioremediation but also for the production of antimicrobial products.</p></abstract>

This work aimed to optimize carbon and nitrogen sources for the growth of Enterobacter cloacae B14 and its biosurfactant (BS) production via One-Variable-At-a-Time (OVAT) method. The BS stability under a range of pH and temperatures was assessed. Antimicrobial activity against Gram-positive and Gram-negative pathogens was determined by the agar well diffusion method. The results showed that the optimum carbon and nitrogen sources for BS production were maltose and yeast extract, respectively, with a maximum BS yield of (39.8 ± 5.2) mg BS/g biomass. The highest emulsification activity (E24) was 79%, which is significantly higher than in the previous studies. We found that B14 BS can withstand a wide range of pH values from 2 to10. It could also function under a range of temperatures from 30–37°C. Thin Layer Chromatography (TLC) and Fourier Transform Infrared Spectrometry (FTIR) analysis confirmed that B14 BS is a glycolipid-like compound, which is rarely found in Enterobacter spp. Cell-free broth showed inhibition against various pathogens, preferable to Gram-positive ones. It had better antimicrobial activity against Bacillus subtilis than a commonly-used antibiotic, tetracycline. Furthermore, B14 broth could inhibit the growth of a tetracycline-resistant Serratia marcescens. Our results showed promising B14 BS applications not only for bioremediation but also for the production of antimicrobial products.

Improved Biosurfactant Production by <italic>Enterobacter cloacae</italic> B14, Stability Studies, and its Antimicrobial Activity

Polish Journal of Microbiology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Improved Biosurfactant Production by  B14, Stability Studies, and its Antimicrobial Activity

This work aimed to optimize carbon and nitrogen sources for the growth of Enterobacter cloacae B14 and its biosurfactant (BS) production via...

Improved Biosurfactant Production by Enterobacter cloacae B14, Stability Studies, and its Antimicrobial Activity

Article Category: original-paper

Published Online: Aug 14, 2020

Page range: 273 - 282

Received: Mar 09, 2020

Accepted: Jun 19, 2020

DOI: https://doi.org/10.33073/pjm-2020-030

Keywords
biosurfactant, cultivation media, antimicrobial activity, stability

© 2020 Jindarat Ekprasert et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Improved Biosurfactant Production by Enterobacter cloacae B14, Stability Studies, and its Antimicrobial Activity

Article Category: original-paper

Published Online: Aug 14, 2020

Page range: 273 - 282

Received: Mar 09, 2020

Accepted: Jun 19, 2020

DOI: https://doi.org/10.33073/pjm-2020-030

Keywordsbiosurfactant, cultivation media, antimicrobial activity, stability

© 2020 Jindarat Ekprasert et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Keywords
biosurfactant, cultivation media, antimicrobial activity, stability