title: Evaluation of culture medium for nisin production in a repeated-batch biofilm reactor.
abstract: In this study, a biofilm reactor with plastic composite support (PCS), made by high-temperature extrusion of agricultural products and polypropylene, was evaluated for nisin production using L. lactis strain NIZO 22186. The high-biomass density of the biofilm reactor was found to contribute to a significantly shorter lag time of nisin production relative to a suspended-cell reactor. In comparison to glucose (579 IU/mL), sucrose significantly increased the nisin production rate by 1.4-fold (1100 IU/mL). However, results revealed that high levels of sucrose (8% w/v) had a suppressing effect on nisin production and a stimulating effect on lactic acid production. A high concentration of MgSO4.7H2O at 0.04% (w/v) was found to reduce the nisin production, while concentrations of KH2PO4 of up to 3% (w/v) did not have any significant effect on growth or nisin production. The best of the tested complex media for nisin production using the PCS biofilm reactor consisted of 4% (w/v) sucrose, 0.02% (w/v) MgSO4.7H2O, and 0.1% (w/v) KH2PO4. Nisin production rate in the biofilm reactor was significantly increased by 3.8-fold (2208 IU/mL) when using the best complex medium tested.
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Thunyarat
authors.initials: T
authors.lastname: Pongtharangkul
authors.forename: Ali
authors.initials: A
authors.lastname: Demirci
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D018441:Biofilms; D019149:Bioreactors; D003470:Culture Media / Q000737:chemistry* / Q000494:pharmacology; D013294:Lactococcus lactis / Q000187:drug effects / Q000378:metabolism*; D009561:Nisin / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D009561:Nisin