Abstract
This work aimed to optimize the parameters affecting partitioning of a bacteriocin-like inhibitory substances (BLIS) from Lactococcus lactis Gh1 in extractive fermentation using polyethylene glycol (PEG)/dextran aqueous two-phase system (ATPS). This system was developed for the simultaneous cell cultivation and downstream processing of BLIS. Results showed that the molecular weight of PEG, PEG concentration, and dextran T500 affect the partition coefficient (K), purification factor (PF), and yield of BLIS partitioning. ATPS composed of 10% (w/w) PEG2000 and 8% (w/w) dextran T500, provided the greatest conditions for the extractive BLIS production. The K (1.00 ± 0.16), PF (2.92 ± 0.37) and yield (77.24 ± 2.81%) were increased at selected orbital speed (200 rpm) and pH (pH 7). Sustainable growth of the cells in the bioreactor and repeated fermentation up to the eighth extractive batch were observed during the scale up process, ensuring a continuous production and purification of BLIS. Hence, the simplicity and effectiveness of ATPS in the purification of BLIS were proven in this study.
Highlights
This study aims to establish an in situ continuous production and extraction approaches of bacteriocin-like inhibitory substances (BLIS) by L. lactis Gh1 using the aqueous two-phase system (ATPS) with PEG2000 and dextran T500
The growth compatibility of Lactococcus lactis Gh1 and bacteriocins-like-inhibitory substance (BLIS) production in different types and concentrations of polymer and salts/dextran are shown in Tables 2 and 3, respectively
BLIS production significantly affected by molecular weight of polyethylene glycol (PEG)
Summary
Lactic acid bacteria (LAB) have a long history of use in the food and have a reputation of being ‘generally recognized as safe’ (GRAS). Due to their potential to inhibit or limit contamination by spoilage and/or disease microorganisms through the synthesis of diverse antimicrobial chemicals such as organic acid, hydrogen peroxide, ethanol, diacetyl, carbon dioxide, bacteriocin or antibiotic-like substances, LAB are extensively being used in the food industry [2]. Bacteriocins/bacteriocin-like inhibitory substances (BLIS) (unclassified bacteriocin with similar activity that can be identified using the same quantification methods as bacteriocin) are proteinaceous antimicrobial compounds
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