Aqueous two-phase flotation for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10

An aqueous two-phase flotation (ATPF) system based on polyethylene glycol (PEG) and sodium citrate (NaNO3C6H5O7 center dot 2H(2)O) was considered for primary recovery of bacteriocin-like inhibitory substance (BLIS) from Pediococcus acidilactici Kp10. The effects of ATPF parameters namely phase composition, tie-line length (TLL), volume ratio between the two phases (V-R), amount of crude load (C-L), pH, nitrogen gas flow rate (F-R) and flotation time (F-T) on the performance of recovery were evaluated. BLIS was mainly concentrated into the upper PEG-rich phase in all systems tested so far. The optimum conditions for BLIS purification, which composed of PEG 8000/sodium citrate, were: TLL of 42.6, V-R of 0.4, C-L of 22% (w/w), pH 7, average F-T of 30 min and F-R of 20 mL/min. BLIS was partially purified up to 5.9-fold with a separation efficiency of 99% under this optimal conditions. A maximum yield of BLIS activity of about 70.3% was recovered in the PEG phase. The BLIS from the top phase was successfully recovered with a single band in SDS-gel with molecular weight of about 10-15 kDa. ATPF was found to be an effective technique for the recovery of BLIS from the fermentation broth of P. acidilactici Kp10. (C) 2016 Elsevier B.V. All rights reserved.