Liquid-liquid extraction of protease from coldadapted yeast Rhodotorula mucilaginosa L7 using biocompatible and biodegradable aqueous twophase systems

LUCIANA D. LARIO; LUCIANA PELLEGRINI MALPIEDI; FERNANDO BRANDAO PEREIRA; LARA DURAES SETTE; ADALBERTO PESSOA JR.

SEPARATION SCIENCE AND TECHNOLOGY

TAYLOR & FRANCIS INC

Lugar: Londres; Año: 2015 vol. 51 p. 57 - 67

0149-6395

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 23-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.