Production of surfactin and fengycin by Bacillus subtilis in a bubbleless membrane bioreactor

Abstract

Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air-liquid contactor to prevent foam formation. Three different configurations were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume was in the same range: 242, 230, and 188 mg l(-1) for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l(-1) for BB1, 207 mg l(-1) for BB2, and 393 mg l(-1) for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with the submerged polypropylene membrane.

Applications of a lipopeptide biosurfactant, surfactin, produced by microorganisms

“…Coutte et al were the first to produce surfactin and fengycin from B. subtilis in a bubbleless bioreactor using a hollow fiber membrane as a air-liquid contactor [98]. They established that bubbleless bioreactors readily support bacterial growth and the production of lipopeptides without the formation of foam, preventing the loss of surfactin.…”

Surfactin and Other Lipopeptides from Bacillus spp.

“…With the same idea of developing a continuous process for surfactin and fengycin extraction, a membrane bioreactor was tested. The use of a membrane to ensure the oxygen transfer in bubbleless conditions allowed to avoid foam formation, leading to the development of a membrane bioreactor with cell recycling by microfiltration and lipopeptide concentration by ultrafiltration (Coutte et al 2010b). …”

Determinación de metabolitos secundarios a partir de Bacillus subtilis con efecto biocontrolador sobre Fusarium sp.

“…subtilis se considera que es un aerobio estricto, pero varios grupos han demostrado que esta especie bacteriana es capaz de crecer incluso con un suministro de oxígeno limitado. Se encontró que el suministro suficiente de oxígeno disuelto (DO) desempeña un papel crucial en la eficiente producción de lipopéptidos (27).…”