A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Optimizing the medium components in bioemulsifiers production by Candida lipolytica with response surface method

A response surface methodology was used to study bioemulsifier production by Candida lipolytica. A 2(4) full experimental design was previously carried out to investigate the effects and interactions of the concentrations of corn oil, urea, ammonium sulfate, and potassium dihydrogen orthophosphate on the emulsification activity (EA) of the bioemulsifier produced by C. lipolytica. The best EA value (3.727 units of emulsification activity (UEA)) was obtained with a medium composed of 0.4 g of urea, 1.1 g of ammonium sulfate, 2.04 g of potassium dihydrogen orthophosphate, 5 mL of corn oil, 50 mL of distilled water, and 50 mL of seawater. A curvature check was performed and revealed a lack of fit of the linear approximation. The proximity of the optimum point was evident, as was the need for quadratic model and second-order designs that incorporate the effect of the curvature. Medium constituents were then optimized for the EA using a three-factor central composite design and response surface methodology. The second-order model showed statistical significance and predictive ability. It was found that the maximum EA produced was 4.415 UEA, and the optimum levels of urea, ammonium sulfate, and potassium dihydrogen orthophosphate were, respectively, 0.544% (m/v), 2.131% (m/v), and 2.628% (m/v).52657558

Partition of trypsin in aqueous two-phase systems of poly(ethylene glycol) and cashew-nut tree gum

The partition behaviour of trypsin in poly(ethylene glycol) (PEG)-cashew-nut tree gum aqueous two-phase systems has been characterized. The enzyme partitioned preferentially into the cashew-nut tree gum phase. Investigation on the effect of the molecular weight of the PEG, the pH of system and the tie-line length of the biphasic diagram lead to the conclusion that the system properties had little effect on trypsin partition coefficients. In some cases, the NaCl addition changed dramatically the partition coefficient, this means that altering the conditions allows the manipulation of the protein partition. Maximum recovery of trypsin activity in the cashew-nut tree gum phase was obtained with PEG (molecular weight 8000) at pH 7.0 and 1.0 M NaCl. (C) 2002 Elsevier Science Ltd. All rights reserved.38569369

Physical and rheological characterisation of polyethylene glycol-cashew-nut tree gum aqueous two-phase systems

The characterisation of the polyethylene glycol-cashew-nut tree gum aqueous two-phase system is described. Factors which affect the phase diagram including polymer molecular mass, pH and temperature were analysed. The physicochemical properties of the system such as density, viscosity, volume ratio and phase separation times were also described. The characteristics of the system studied indicate it to be very attractive as a separation technique. (C) 2002 Elsevier Science B.V. All rights reserved.7661273

Performance of a perforated rotating disc contactor in the continuous extraction of a protein using the PEG-cashew-nut tree gum aqueous two-phase system

The characterisation of bovine serum albumin (BSA) mass transfer mechanisms in a perforated rotating disc contactor (PRDC) using an aqueous two-phase system (ATPS) composed of poly(ethylene glycol) (PEG) and a polysaccharide, the cashew-nut tree gum, was described. The PEG-rich phase was used as the dispersed phase and protein transfer took place from the dispersed to the continuous phase. Studies of the effect of dispersed phase velocity, system composition and disc rotation speed on either protein mass transfer coefficients or column hold-up showed that the dispersed phase hold-up and the volumetric mass transfer coefficient increased with increasing the dispersed phase velocity and disc rotation speed. (C) 2003 Elsevier Science B.V. All rights reserved.16322122