Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jul 24;8(1):122.
doi: 10.1186/s13568-018-0651-y.

Production of rhamnolipids by integrated foam adsorption in a bioreactor system

Iva Anic  1 , Ines Apolonia  2 , Pedro Franco  2 , Rolf Wichmann  3
Affiliations

Production of rhamnolipids by integrated foam adsorption in a bioreactor system

Iva Anic et al. AMB Express. .

Abstract

Biosurfactants offer environmental as well as health benefits over traditionally used chemical surfactants and heterologous production from engineered microorganisms has been demonstrated, offering containable as well as scalable production of these alternative chemicals. Low product titers and cost intensive downstream processing are the main hurdles for economical biosurfactant production at industrial scales. Increased biosurfactant concentrations are found in the liquid fraction of the foam formed during fermentation of producing microbes. Adsorption of biosurfactants from foam fractions in cultivations may offer a simple concentration and purification method which could enable their cost-effective production. Here, foam adsorption was applied as an in situ method for separation of the rhamnolipid biosurfactants during fermentation of Pseudomonas putida EM383. An integrated process was designed to capture the produced rhamnolipids on hydrophobic adsorbent in packed bed units while minimizing the impact of adsorption on the productivity of the system by recirculating cell-containing collapsed foam flow-through back into the reactor vessel. A stable rhamnolipid production by P. putida EM383 on glucose was performed coupled to this adsorption strategy for 82 h, after which no remaining rhamnolipids were found in the cultivation broth and 15.5 g of rhamnolipids could be eluted from the adsorbent. Rhamnolipid yield from glucose feed was 0.05 g g-1, when up to 2 g L-1 glucose pulse feeding was applied. After solvent evaporation, a product purity of 96% was obtained. The results indicate that the integrated adsorption method can be efficient for simultaneous production and recovery of rhamnolipid biosurfactants from microbial fermentations.

Keywords: Biosurfactant; Foam adsorption; Foam fractionation; Integrated process; Process intensification; Rhamnolipids.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1
Concept of rhamnolipid separation from fermentation broth using foam technology principle
Fig. 2
Fig. 2
Laboratory setup (a) and process flow sheet (b) of automated adsorption unit. Adsorption columns were used alternatively, where adsorption phase was set to 12 h. In non-adsorptive column mode, elution and preparation for the next run were performed
Fig. 3
Fig. 3
Time course of overall biomass, glucose and rhamnolipid concentrations during cultivations of integrated fermentation are shown. Feed was started at time 24 h. Values of biomass (circles), glucose (squares) and rhamnolipids (triangles) concentrations of two integrated cultivations are given as mean value
Fig. 4
Fig. 4
Time course of differential bacterial (circles) and rhamnolipid (triangles) enrichment in the foam during integrated fermentations. Foam samples were taken at the sampling port on the foam exit at the top of the bioreactor. The values for bacterial and rhamnolipid enrichment were calculated according to Eq. 4
Fig. 5
Fig. 5
Volumetric flow of the foam during the integrated fermentations. Foam volume and bacterial and rhamnolipid concentrations were measured after 30 min long foam collapse in the collection tube at room temperature
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Alonso S, Martin PJ. Impact of foaming on surfactin production by Bacillus subtilis: implications on the development of integrated in situ foam fractionation removal systems. Biochem Eng J. 2016;110:125–133. doi: 10.1016/j.bej.2016.02.006. - DOI
    1. Anic I, Nath A, Franco P, Wichmann R. Foam adsorption as an ex situ capture step for surfactants produced by fermentation. J Biotechnol. 2017;258:181–189. doi: 10.1016/j.jbiotec.2017.07.015. - DOI - PubMed
    1. Banat IM, Satpute SK, Cameotra SS, Patil R, Nyayanit NV. Cost effective technologies and renewable substrates for biosurfactants’ production. Front Microbiol. 2014;5:697. doi: 10.3389/fmicb.2014.00697. - DOI - PMC - PubMed
    1. Beuker J, Steier A, Wittgens A, Rosenau F, Henkel M, Hausmann R. Integrated foam fractionation for heterologous rhamnolipid production with recombinant Pseudomonas putida in a bioreactor. AMB Express. 2016;6:11. doi: 10.1186/s13568-016-0183-2. - DOI - PMC - PubMed
    1. Chandra R, editor. Advances in biodegradation and bioremediation of industrial waste. Boca Raton: CRC Press; 2015.

LinkOut - more resources