A food-grade process for isolation and partial purification of bacteriocins of lactic acid bacteria that uses diatomite calcium silicate

Abstract

Bacteriocins, including nisin, pediocin PO2, brevicin 286, and piscicolin 126, were extracted from fermentation media by adsorption onto Micro-Cel (a food-grade diatomite calcium silicate anticaking agent) and subsequent desorption. The optimal conditions for desorption of piscicolin 126 were determined and applied to other bacteriocins, and the relative purities of the desorbed preparations were compared. Piscicolin was not successfully desorbed from Micro-Cel at pH 1.0 to 12.0, with organic solvents, or by increase of ionic strength up to 1 M NaCl. However, 25 and 75% of the bacteriocin activity was desorbed by using 1% sodium deoxycholate and 1% sodium dodecyl sulfate (SDS), respectively. Higher levels (up to 100%) of desorption were achieved by repeated elution or by an increase in surfactant concentration. Desorption of piscicolin with 1/10 volume of SDS solution resulted in a preparation with 10 times concentration in activity, equivalent to that of ammonium sulfate preparations (409,600 to 819,200 activity units/ml). Determination of organic nitrogen (N) content revealed that the desorbed piscicolin preparations were substantially free of proteinaceous substances (approximately 92 to 99%) compared with original culture supernatants and ammonium sulfate preparations. Nisin, pediocin, and brevicin were also desorbed with 1% SDS with a similar level of purification.

Sakacin‐A antimicrobial packaging for decreasing Listeria contamination in thin‐cut meat: preliminary assessment

“…16 In practical terms, purification to homogeneity is redundant and sometimes not suitable for food-grade application. 17 In the present work, sakacin-A was concentrated from a food-grade medium by one-step diafiltration, giving a freeze-dried enriched sakacin-A free from contaminant proteins and with an antimicrobial titer of 1.36 AU mg −1 . Total activity yield was nearly 20% better than other methods of rapid purification (10% in Guyonnet et al 16 ), although lower than vastly time-consuming methods (83% in Holck et al 9 ).…”

Purification, amino acid sequence and mode of action of bifidocin B produced by Bifidobacterium bifidum NCFB 1454

“…Adsorption of bifidocin B onto Micro‐Cel (diatomate calcium silicate; Celite Corporation, Lompoc, CA, USA) was achieved using the method of Coventry et al . (1996) with the following modifications.…”

EFFECTS OF BIFIDOCIN B AND LACTOCOCCIN R ON THE GROWTH OF LISTERIA MONOCYTOGENES AND BACILLUS CEREUS ON STERILE CHICKEN BREAST

“…The freeze-dried supernatants were reconstituted with 150 mL of distilled water, and their pH values were adjusted to 6.0 with 5-M phosphoric acid or 5-M NaOH. Micro-Cel (food grade diatomite calcium silicate; Celite Corporation, Lompoc, CA) was added to yield 2% (w/v) (Coventry et al 1996). The samples were stirred overnight at 4C for bacteriocin adsorption onto Micro-Cel and then centrifuged at 1,000 ¥ g for 20 min.…”