Technology of fermentation coupling with foam separation for improving the production of nisin using a κ-carrageenan with loofa sponges matrix and an hourglass-shaped column

There are two problems in the technology of the fermentation coupling with foam separation: stripping of bacteria into the foam and large volume of interstitial liquid. In order to solve these problems, cell immobilization was utilized in this technology and a new carrier by combining κ-carrageenan and loofa sponge was designed to successfully immobilize Lactococcus lactis supsp. Lactis ATCC 11454. A novel hourglass-shaped column was developed to effectively enhance foam drainage. Continuous fermentation of immobilized cells coupling with foam separation was carried out for 100 h and a maximum total nisin titer of 4.91 × 103 IU/mL was achieved. Nisin productivity of 3.92 × 102 IU/mL h in continuous + coupled foam separation was higher than that in continuous + uncoupled foam separation (3.20 × 102 IU/mL h) and batch fermentation (2.36 × 102 IU/mL h). The current study demonstrated that this technology significantly enhanced the production of nisin and would be useful in scaling-up of the fermentation process for improving the production of nisin.