Efeitos da massa molar e do pH sobre o equilíbrio termodinâmico do sistema bifásico aquoso PEG/fosfatos

Abstract

Sistemas bifásicos aquosos têm sido muito utilizados, em pesquisas, na separação e purificação de biomoléculas. São formados pela mistura de dois polímeros hidrofílicos, ou de um polímero e um sal. O objetivo principal deste trabalho foi caracterizar um sistema bifásico aquoso (SBA) a partir da preparação de soluções estoques de PEG com massas molares de 1500, 4000 e 6000 e tampões fosfato variando de 6 a 8, em condições normais. Nos diagramas de fases PEG/fosfato, foi observado um deslocamento da binodal para os valores de menores concentrações dos polímeros e com o aumento do peso molecular do PEG. Por outro lado, a variação do pH não mostrou um deslocamento significativo da binodal. Em relação às linhas de amarração, os valores das composições não se alteram muito, mesmo quando os polímeros são comparados entre si e a diferentes pHs.

Extraction of fibrinolytic proteases from Streptomyces sp. DPUA1576 using PEG-phosphate aqueous two-phase systems

“…Myoglobin partition studies using PEG/poly(acrylic acid), with PEG with molecular mass from 4000 to 10,000 g/mol, demonstrated a decrease on K from 15.77 to 4.33, whereas for ovalbumin the decrease was from 5.51 to 3.09 [29]. Low values for partition coefficient of bromelain were also observed by Ketnawa weights (2000-6000 g/mol).…”

“…Experimental design results for partition coefficient (K) of fibrinolytic protease extraction using ATPS PEG/phosphate are presented in Table 3. According to binodal curve obtained with PEG 1500 g/mol [29], no phase separation was observed for runs (1, 2 and 9) as salt and PEG concentrations were below the curve. In conformity with the results presented in Table 3, in the majority of runs, fibrinolytic protease partition occurred preferentially on the top phase rich in PEG.…”

Stability of clavulanic acid in PEG/citrate and liquid–liquid extraction in aqueous two-phase system

“…The ATPS are a convenient and appropriate method for the extraction of biological substances due to the high water content (between 70% and 90%) in both phases. This provides a pleasant environment to work with biologically active compounds because it preserves its molecular stability [9].…”

Study on extraction and separation of butyric acid from clostridium tyrobutyricum fermentation broth in PEG/Na2SO4 aqueous two-phase system

“…Specifically, sodium sulfate saturated solution was employed to precipitate carbohydrate and nitrogen compounds in clostridium tyrobutyricum fermentation broth, followed by adding polyethylene glycol (PEG)/sodium sulfate ATPS for butyric acid extraction from the broth. The ATPS method is characterized by low energy consumption and possibility of reusing the extraction agents [6][7][8][9][10][11]. We investigated the effects of different ATPSs on the extraction yield of butyric acid, and systematically studied the extraction conditions by a single factor and response surface analysis (RSA), so as to obtain a new process for the efficient extraction of butyric acid from a fermentation broth.…”