Extraction and purification of violacein from Yarrowia lipolytica cells using aqueous solutions of surfactants

BACKGROUND: L-Asparaginase (ASNase) is an important biopharmaceutical for the treatment of acute lymphoblastic leukemia (ALL); however, with some restrictions due to its high manufacturing costs. Aqueous biphasic systems (ABS) have been suggested as more economical platforms for the separation/purification of proteins, but a full understanding of the mechanisms behind the ASNase partition is still a major challenge. Polymer/salt-based ABS with different driving-forces (salting-out and hydrophilicity/hydrophobicity effects) were herein applied to control the partition of commercial ASNase. RESULTS: The main results showed the ASNase partition to the salt- or polymer-rich phase depending on the ABS studied, with extraction efficiencies higher than 95%. For systems composed of inorganic salts, the ASNase partition was controlled by the polyethylene glycol (PEG) molecular weight used. Cholinium-salts-based ABS were able to promote a preferential ASNase partition to the polymer-rich phase using PEG-600 and to the salt-rich phase using a more hydrophobic polypropylene glycol (PPG)-400 polymer. It was possible to select the ABS composed of PEG-2000 + potassium phosphate buffer as the most efficient to separate the ASNase from the main contaminant proteins (purification factor = 2.4 ± 0.2), while it was able to maintain the enzyme activity for posterior application as part of a therapeutic. CONCLUSION: Polymer/salt ABS can be used to control the partition of ASNase and adjust its purification yields, demonstrating the ABS potential as more economic platform for the selective recovery of therapeutic enzymes from complex broths.publishe

Alkaloids as alternative probes to characterize the relative hydrophobicity of aqueous biphasic systems

In order to overcome the lack of characterization on the relative hydrophobicity of aqueous biphasic systems (ABS), the partition of three alkaloids as alternative probes, was evaluated in a series of biocompatible ABS composed of cholinium-based salts or ionic liquids (ILs) and polyethylene glycol (PEG). The caffeine partitioning in ABS was firstly addressed to infer on the effect of the phase-forming components composition. In all systems, caffeine preferentially concentrates in the lower water content PEG-rich phase. Additionally, a linear dependence between the logarithmic function of the partition coefficients and the water content ratio was found. To confirm this linear dependency, the partition coefficients of caffeine, theobromine and theophylline were determined in other ABS formed by different cholinium-based salts/ILs. In most systems, it is shown that all alkaloids partition to the most hydrophobic phase. To support the experimental results, COSMO-RS (Conductor-like Screening Model for Real Solvents) was used to compute the screening charge distributions of both phaseforming components of ABS and alkaloids, the excess enthalpy of mixing and the activity coefficients at infinite dilution. It is here demonstrated that the partition trend of alkaloids can be used to address the relative hydrophobicity of the coexisting phases in polymer-salt/-IL ABS

Review: Sophorolipids A Promising Biosurfactant and it's Applications

ABSTRACT: Sophorolipids (SLPs) are the most promising glycolipid biosurfactants produced in large quantity by several nonpathogenic yeast species, among these Candida bombicola ATCC 22214 is the most studied SLP producing yeast. SLPs composed by the disaccharide sophorose (2'-O-β-D-glucopyranosyl-β-D-glycopyranose) linked (β -glycosidically) to a long fatty acid chain with generally 16 to 18 atoms of carbon with one or more unsaturation. These compounds have characteristics, which are similar or even superior to the other biosurfactants and surfactants. Some of these advantages are environmental compatibility, high biodegradability, low toxicity, high selectivity and specific activity in a broad range of temperature, pH and salinity conditions. They fulfill the eco-friendly criteria combine Green chemistry and a lower carbon footprint. SLP possess a great potential for application in areas such as: Agriculture, Food, Biomedicine, Bioremediation, Cosmetics and Enhanced Oil Recovery