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BACKGROUND PEGylation, defined as the covalent attachment of polyethylene glycol, allows the synthesis of PEGylated therapeutic proteins with enhanced physicochemical properties. Traditional alkylating Nterminal PEGylation reactions on amine groups involve the use of modified linear mono-methoxy polyethylene glycol (mPEG) molecules looking for the synthesis of mono-PEGylated products. However, this approach requires different purification steps since inevitably undesired cross-linked products are synthesized. Herein, we propose the use of reactive aqueous two-phase systems (ATPS) to produce and purify PEGylated therapeutic conjugates using Ribonuclease A (RNase A) as a model protein. RESULTS: Selected linear 5 kDa and 20 kDa mPEG ­ potassium phosphate systems were produced according to equilibrium data obtained from constructed binodal curves. All reactive systems were able to generate biphasic systems and to PEGylate RNase A. Two 5 kDa and two 20 kDa systems were selected based on the reaction yield percentage and the feasibility of purifying the mono-PEGylated RNase A from the diPEGylated and native RNase A by contrasting the differences in their partition behaviors. The remnant biological activity was of 94% and of 100% for the mono-PEGylated RNase A purified from the 5 kDa and 20 kDa mPEG systems when compared to the mono-PEGylated conjugate obtained by standard procurement methods.

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The partitioning and purification of lectins from the crude extract of Cratylia mollis seeds (Cramoll 1,4) was investigated in aqueous two-phase systems (ATPS). A factorial design model (24) was used to evaluate the influence of polyethylene glycol (PEG) molar mass (1500-8000 g/mol), PEG concentration (12.5-17.5% w/w), phosphate (10-15% w/w) concentration, and pH (6-8) on the differential partitioning, purification factor, and yield of the lectin. Polymer and salt concentration were the most important variables affecting partition of lectin and used to find optimum purification factor by experimental Box-Behnken design together with the response surface methodology (RSM). ATPS showed best conditions composed by 13.9% PEG1500, 15.3% phosphate buffer at pH 6, which ensured purification factor of 4.70. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a single band of protein with 26.1 kDa. Furthermore, results demonstrated a thermostable lectin presenting activity until 60 °C and lost hemagglutinating activity at 80 °C. According to the obtained data it can be inferred that the ATPS optimization using RSM approach can be applied for recovery and purification of lectins.

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Aqueous two-phase systems have been studied for almost a century to separate biomolecules in harmless conditions. Proteases produced by Aspergillus tamarii URM 4634 were extracted in polyethylene glycol (PEG)/phosphate aqueous two-phase system under discontinuous and continuous (perforated rotative discs column) process. On the discontinuous process, it was evaluated the effect of operational conditions (PEG molar mass and its concentration, phosphate concentration and pH) over the partition coefficient, activity yield and purification factor. Protease partitioned to PEG-phase with partition coefficients up to 55.73. The best process parameters were 17.5% of PEG, with molar mass 8000 g·mol-1, 15% of phosphate salt at pH 6, with 113.15% of activity yield and purification factor of 2.62. Under continuous extraction, hold up data showed that 57.1% of the discontinuous phase was available for protein extraction. Further, separation achieved 90.0% of efficiency. The yields surpassed 100% in almost all runs, and the best purification factor was 1.84, with both flows of 2 mL·min-1. Thus, the best operational conditions reached an activity yield of 95.3% and 90.0% of separation efficiency. Hence, aqueous two-phase system PEG/phosphate extraction is an efficient process for separation of proteases produced by Aspergillus tamarii URM 4634, under continuous extraction likewise under discontinuous process.

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Hydrophobin-fused domain III of dengue envelope proteins serotypes 1 and 2 were expressed in Rachiplusia nu larvae and purified by aqueous two-phase system. This biotechnological approach of hydrophobin-fused proteins, which allowed obtaining 97.7 µg/larva of fusion protein DomIII serotype 1 and 61.4 µg/larva of fusion protein DomIII serotype 2, represents an integrated strategy for simple production of recombinant antigens. Purified fusion proteins induced serotype-specific neutralizing antibodies without cross-reaction against other serotypes and arboviruses after mouse immunization. hydrophobin-fused domain III of dengue envelope protein could be a promising strategy for easy and low-cost production of components of a tetravalent sub-unit vaccine against dengue.

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As enzimas fibrinolíticas podem ser obtidas de micro-organismos por meio de processos fermentativos. O presente trabalho teve como objetivo avaliar a produção e extração integrada da protease fibrinolítica de Mucor subtilissimus UCP 1262 usando sistema de duas fases aquosas (SDFA). O processo integrado foi realizado para avaliar a produção, partição e recuperação da protease fibrinolítica, segundo planejamento experimental 23, utilizando como variáveis independentes a massa molar do polietileno glicol (PEG), a concentração do PEG e a concentração do sulfato de sódio. A maior atividade fibrinolítica (15,40U/mL) foi obtida na fase rica em sulfato de sódio no ensaio composto por 10% de sal e 18% de PEG 8000 (g/mol). Recuperações superiores a 80% foram obtidas. A protease fibrinolítica apresentou pH ótimo 7,0, estabilidade entre os pH 6,0 e 8,5, temperatura ótima 50°C, sendo estável de 10°C a 50°C. A enzima foi classificada como uma serino protease, com massa molecular de 52kDa. Como resultado, o processo é notavelmente eficaz para pré-purificar a protease fibrinolítica com baixo custo e rapidez significativa. Quando comparada a outras técnicas de produção e purificação isoladas, a fermentação extrativa é um processo digno a ser substituto das etapas iniciais de separação convencionais.(AU)

Fibrinolytic enzymes can be obtained from microorganisms through fermentative processes. The study aimed to evaluate the fibrinolytic protease production and integrated extraction from Mucor subtilissimus UCP 1262 by extractive fermentation using Aqueous Two-Phase Systems (ATPS). The integrated process was carried out to assess the production, partition and fibrinolytic enzyme recovery, according to a 2 3 -experimental design, using as independent variables Polyethylene glycol (PEG) molar mass, PEG and sodium sulphate concentration, concentration. The highest fibrinolytic activity (15.40U/mL) was obtained in sodium sulfate rich phase in the assay comprising of 10% of salt and 18% of PEG 8000 (g/mol). Yield greater than 80% was obtained. The fibrinolytic protease presented optimum pH 7.0 and stability between pH 6.0 and 8.5, and optimum temperature 50°C, stable between 10°C to 50°C. The enzyme was classified as a serine-protease with 52kDa of molecular weight. As a result, the process is remarkably effective to pre-purify the fibrinolytic protease with a low cost and significantly faster processing time. When compared to other isolated production and purification techniques the extractive fermentation is worthy of being a candidate to replace the initial stages of conventional separation processes.(AU)

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As enzimas fibrinolíticas podem ser obtidas de micro-organismos por meio de processos fermentativos. O presente trabalho teve como objetivo avaliar a produção e extração integrada da protease fibrinolítica de Mucor subtilissimus UCP 1262 usando sistema de duas fases aquosas (SDFA). O processo integrado foi realizado para avaliar a produção, partição e recuperação da protease fibrinolítica, segundo planejamento experimental 23, utilizando como variáveis independentes a massa molar do polietileno glicol (PEG), a concentração do PEG e a concentração do sulfato de sódio. A maior atividade fibrinolítica (15,40U/mL) foi obtida na fase rica em sulfato de sódio no ensaio composto por 10% de sal e 18% de PEG 8000 (g/mol). Recuperações superiores a 80% foram obtidas. A protease fibrinolítica apresentou pH ótimo 7,0, estabilidade entre os pH 6,0 e 8,5, temperatura ótima 50°C, sendo estável de 10°C a 50°C. A enzima foi classificada como uma serino protease, com massa molecular de 52kDa. Como resultado, o processo é notavelmente eficaz para pré-purificar a protease fibrinolítica com baixo custo e rapidez significativa. Quando comparada a outras técnicas de produção e purificação isoladas, a fermentação extrativa é um processo digno a ser substituto das etapas iniciais de separação convencionais.(AU)

Fibrinolytic enzymes can be obtained from microorganisms through fermentative processes. The study aimed to evaluate the fibrinolytic protease production and integrated extraction from Mucor subtilissimus UCP 1262 by extractive fermentation using Aqueous Two-Phase Systems (ATPS). The integrated process was carried out to assess the production, partition and fibrinolytic enzyme recovery, according to a 2 3 -experimental design, using as independent variables Polyethylene glycol (PEG) molar mass, PEG and sodium sulphate concentration, concentration. The highest fibrinolytic activity (15.40U/mL) was obtained in sodium sulfate rich phase in the assay comprising of 10% of salt and 18% of PEG 8000 (g/mol). Yield greater than 80% was obtained. The fibrinolytic protease presented optimum pH 7.0 and stability between pH 6.0 and 8.5, and optimum temperature 50°C, stable between 10°C to 50°C. The enzyme was classified as a serine-protease with 52kDa of molecular weight. As a result, the process is remarkably effective to pre-purify the fibrinolytic protease with a low cost and significantly faster processing time. When compared to other isolated production and purification techniques the extractive fermentation is worthy of being a candidate to replace the initial stages of conventional separation processes.(AU)

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Collagenases are proteolytic enzymes capable of degrading both native and denatured collagen, reported to be applied in industrial, medical and biotechnological sectors. Liquid-liquid extraction using aqueous two-phase system (ATPS) is one of the most promising bioseparation techniques, which can substitute difficult solid-liquid separation processes, offering many advantages over conventional methods including low-processing time, low-cost material and low-energy consumption. The collagenase produced by Penicillium sp. UCP 1286 showed a stronger affinity for the bottom salt-rich phase, where the highest levels of collagenolytic activity were observed at the center point runs, using 15.0% (w/w) PEG 3350 g/mol and 12.5% (w/w) phosphate salt at pH 7.0 and concentration. The enzyme was characterized by thermal stability, pH tolerance and effect of inhibitors, showing optimal collagenolytic activity at 37 °C and pH 9.0 and proved to be a serine protease. ATPS showed high efficiency in the collagenase purification, confirmed by a single band in SDS/PAGE, and can in fact be applied as a quick and inexpensive alternative method.

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A fibrinolytic protease from M. subtilissimus UCP 1262 was recovered and partially purified by polyethylene glycol (PEG)/sodium sulfate aqueous two-phase systems (ATPS). The simultaneous influence of PEG molar mass, PEG concentration and sulfate concentration on the enzyme recovery was first investigated using a 2(3) full factorial design, and the Response Surface Methodology used to identify the optimum conditions for enzyme extraction by ATPS. Once the best PEG molar mass for the process had been selected (6000g/mol), a two-factor central composite rotary design was applied to better evaluate the effects of the other two independent variables. The fibrinolytic enzyme was shown to preferentially partition to the bottom phase with a partition coefficient (K) ranging from 0.2 to 0.7. The best results in terms of enzyme purification were obtained with the system formed by 30.0% (w/w) PEG 6000g/mol and 13.2% (w/w) sodium sulfate, which ensured a purification factor of 10.0, K of 0.2 and activity yield of 102.0%. SDS-PAGE and fibrin zymography showed that the purified protease has a molecular mass of 97kDa and an apparent isoelectric point of 5.4. When submitted to assays with different substrates and inhibitors, it showed selectivity for succinyl-l-ala-ala-pro-l-phenylalanine-p-nitroanilide and was almost completely inhibited by phenylmethylsulfonyl fluoride, behaving as a chymotrypsin-like protease. At the optimum temperature of 37°C, the enzyme residual activity was 94 and 68% of the initial one after 120 and 150min of incubation, respectively. This study demonstrated that M. subtilissimus protease has potent fibrinolytic activity compared with similar enzymes produced by solid-state fermentation, therefore it may be used as an agent for the prevention and therapy of thrombosis. Furthermore, it appears to have the advantages of low cost production and simple purification.

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