Setting up and modelling of overflowing fed-batch cultures of Bacillus subtilis for the production and continuous removal of lipopeptides

Abstract

This work is related to the set-up of overflowing exponential fed-batch cultures (O-EFBC) derived from carbon limited EFBC dedicated to the production of mycosubtilin, an antifungal lipopeptide belonging to the iturin family. O-EFBC permits the continuous removal of the product from the bioreactor achieving a complete extraction of mycosubtilin. This paper also provides a dynamical Monod-based growth model of this process that is accurate enough to simulate the evolution of the specific growth rate and to correlate it to the mycosubtilin specific productivity. Two particular and dependant phenomena related to the foam overflow are taken into account by the model: the outgoing flow rate of a broth volume and the loss of biomass. Interestingly, the biomass concentration in the foam was found to be lower than the biomass concentration in the bioreactor relating this process to a recycling one. Parameters of this model are the growth yield on substrate and the maximal specific growth rate estimated from experiments led at feed rates of 0.062, 0.071 and 0.086h(-1). The model was extrapolated to five additional experiments carried out at feed rates of 0.008, 0.022, 0.040, 0.042 and 0.062h(-1) enabling the correlation of the mean specific growth rates with productivity results. Finally, a feed rate of 0.086h(-1) corresponding to a mean specific growth rate of 0.070h(-1) allowed a specific productivity of 1.27mg of mycosubtiling(-1) of dried biomassh(-1).

Surfactin and Other Lipopeptides from Bacillus spp.

“…We also applied this strategy for the production of mycosubtilin. An overflowing exponentially fed batch process (OEFBC) was so defined, which allowed a continuous extraction of the mycosubtilin with high efficiency (Guez et al 2007). With the same idea of developing a continuous process for surfactin and fengycin extraction, a membrane bioreactor was tested.…”

Lipopeptides in cosmetics

“…The additional properties of thermo, halo, pH and alkaline stability [34][35][36][37][38] enabling the formulation of a wide variety of cosmetic dosage forms. Factors which influenced production, for example, pH, an incubation temperature and an inoculum size as well as the optimized ratio of carbon and nitrogen (3, 9 and 15) with preparation methods have previously been extensively studied and informatively presented [14,[36][37][38][39][40][41][42][43][44][45][46][47][48]. Furthermore, the biosynthesis of lipopeptides made progress by genetic engineering technologies [5,12,49,50] enabling sufficient production of this biomass.…”

Process improvement for fermentation coupling with foam separation: a convenient strategy for cell recycle

“…The recovery Figure 5. Fermentation coupling with foam separation comparing with shake-flask culture (Total titer is obtained by Eqn (7) ). SF is referring to culture shake flask (blank control); FF is referring to fermentation coupling with foam separation).…”

“…Intensive research efforts of FCFS have focused on parametric study, [2,6] mathematical model. [4,7] There were rarely studies on process improvement for this technology such as how to control the biomass overflowing. [3] However, the influence of biomass overflowing, which has adverse effects on specific productivity, [8] total titer, and downstream separation process, [9] cannot be ignored.…”