Liquid-liquid extraction of protease from cold-adapted yeast Rhodotorula mucilaginosa L7 using biocompatible and biodegradable aqueous two-phase systems

• Published in: Separation science and technology 2016-01, Vol.51 (1), p.57-67
• Main Authors: Lario, Luciana Daniela, Malpiedi, Luciana Pellegrini, Pereira, Jorge Fernando Brandão, Sette, Lara Durães, Pessoa-Junior, Adalberto
• Format: Article
• Language: English
• Subjects: aqueous two phase systems; Binary systems (materials); Biodegradability; cold-adapted microorganisms; liquid-liquid extraction; Partitioning; Polyethylene glycol; Protease; Purification; Rhodotorula mucilaginosa; Sodium; Yeast
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496395.2015.1080276

This work aimed to optimize the extraction of an extracellular protease produced by the cold-adapted yeast Rhodotorula mucilaginosa L7 using aqueous two-phase systems (ATPS) comprising polyethylene glycol (PEG) and sodium citrate or sodium tartrate. First, the biocompatibility of the phase forming agents was assessed. The results obtained with PEG-2000, PEG-4000, and PEG-6000 demonstrated that even at large PEG concentrations (32 wt%) the protease maintains its activity after 3 h of reaction, whereas an increase in salt concentration provokes a gradual decrease in protease stability. Subsequently, the partitioning of the protease in both types of ATPS was assessed, evaluating the effect of temperature, molecular weight, and concentration of PEG on protease purification, using two 2 3 -full factorial designs. The best partitioning conditions were obtained in PEG-6000/sodium tartrate-based ATPS, at 30ºC (with a yield of 81.09 ± 0.66% and a purification factor of 2.51 ± 0.03). Thus, considering the biodegradable characteristics of the system, the PEG/sodium tartrate ATPS is a viable and economic low-resolution step in protease purification, with a strong potential for future industrial application.