κ-Carrageenan as a carrier in affinity precipitation of yeast alcohol dehydrogenase

kappa-Carrageenan is a non-toxic polymer from seaweeds, which becomes reversibly insoluble upon the addition of K(+). Its conjugate with the dye, Cibacron Blue 3GA, was used to purify alcohol dehydrogenase from crude yeast extract by affinity precipitation. Response surface methodology was used to optimize conditions for affinity precipitation of the enzyme with the polymer-dye conjugate. Recovery of 58% of the enzyme activity with 13.6-fold purification was obtained.

Magnetic alginate microparticles for purification of $alpha;-amylases

Spherical magnetic alginate microparticles (25-60 microm in diameter) were prepared using the microemulsion system, with water-saturated 1-pentanol as the organic phase. The limited solubility of 1-pentanol in water enabled simple removal of the organic solvent from the prepared beads with water solution. The prepared alginate microparticles were used as magnetic affinity adsorbents for specific purification of alpha-amylases. Enzyme activity was eluted by 1.0 M maltose. alpha-Amylases from Bacillus amyloliquefaciens and porcine pancreatic acetone powder were purified 9- and 12-fold with 88 and 96% activity recovery, respectively.

kappa-Carrageenan as a new smart macroaffinity ligand for the purification of pullulanase

kappa-Carrageenan is a polysaccharide from red seaweed which gets precipitated by K+ ions and dissolves again in water. This smart, K(+)-responsive polymer was found to selectively bind pullulanase activity from Bacillus acidopullulyticus. Gel filtration on Sephadex G-200 showed the formation of the polymer-pullulanase complex at the pre-precipitation stage. On the other hand, phospholipase D, an enzyme which did not co-precipitate with kappa-carrageenan, did not form any complex with the polymer. Thus, K+ ions could be used to selectively precipitate the pullulanase activity. Then, 92% enzyme activity could be eluted with 1 M maltose solution. The single step protocol resulted in 50-fold purification, with a single band on sodium dodecylsulfate-polyacrylamide gel electrophoresis.

Immobilization of xylan-degrading enzymes from Melanocarpus albomyces IIS 68 on the smart polymer Eudragit L-100

Xylanase of Melanocarpus albomyces IIS 68 was immobilized on Eudragit L-100. The latter is a copolymer of methacrylic acid and methyl methacrylate and is a pH-sensitive smart polymer. The immobilization was carried out by gentle adsorption and an immobilization efficiency of 0.82 was obtained. The enzyme did not leach off the polymer even in the presence of 1 M NaCl and 50% ethylene glycol. The K(m) of the enzyme changed from 5.9 mg ml(-1) to 9.1 mg ml(-1) upon immobilization. The V(max) of the immobilized enzyme showed an increase from 90.9 micro mol ml(-1) min(-1) (for the free enzyme) to 111.1 micro mol ml(-1) min(-1). The immobilized enzyme could be reused up to ten times without impairment of the xylanolytic activity. The immobilized enzyme was also evaluated for its application in pre-bleaching of eucalyptus kraft pulp.

Prospective comparative study of patients with culture proven and high suspicion of adult onset septic arthritis

OBJECTIVE

To investigate whether patients with acute septic arthritis (SA) diagnosed by positive synovial fluid (SF) culture (Newman grade A) have different clinical and serological features from those with sterile SF in whom there is nonetheless a high suspicion of SA (Newman grades B and C).

PATIENTS AND METHODS

A prospective 12 month multicentre hospital based study of adult patients with SA recruited 47 patients with culture positive SA and 35 patients with clinically suspected SA but sterile SF.

RESULTS

Patient demography, clinical and laboratory features at presentation were similar irrespective of the underlying diagnosis, SF culture, and the presence of prosthetic joints. Medical and surgical treatment and outcome were comparable in the two patient groups. Patients with both suspected and proven SA were more likely to be from the more socially deprived areas of our community (p<0.0001).

CONCLUSION

Patients in whom there is a high clinical suspicion of SA are comparable to those patients with SA with a positive SF culture and have similar morbidity and mortality on follow up. Therefore, if clinical suspicion of SA is high then it is correct to treat as SA in the absence of bacterial proof.

Casein hydrolysis in PEG-salt two phase system by Eudragit-chymotrypsin bioconjugate

A bioconjugate of alpha-chymotrypsin and Eudragit S-100 was used in an aqueous two-phase system (polyethylene glycol/phosphate) for casein hydrolysis. More product was obtained by replacing the lower salt phase with a fresh one during the reaction. The bioconjugate could be reused six times for casein hydrolysis.

A smart bioconjugate of chymotrypsin

alpha-Chymotrypsin was immobilized on Eudragit S-100 via covalent coupling with 93% retention of proteolytic activity. The conjugate behaved as a smart biocatalyst and functioned as a pH-dependent reversibly soluble-insoluble biocatalyst. The pH optimum of chymotrypsin broadened on immobilization, and the immobilized preparation showed better stability at and above pH 6.5 as compared to the free enzyme. The immobilized enzyme showed a slight shift in the temperature optimum and enhanced thermal stability retaining 70% of its original activity after 1 h of exposure to 40 degrees C as compared to the 25% residual activity for the free enzyme under identical conditions. K(m) and V(max) values did not change on immobilization. Also, the immobilized preparation was quite stable to reuse, it retained almost 85% of its original activity even after a fifth precipitation cycle. UV spectroscopy and circular dichroism were used to probe structural changes in the enzyme upon immobilization.

Synthesis of antioxidant propyl gallate using tannase from Aspergillus niger van Teighem in nonaqueous media

Tannase from Aspergillus niger van Teighem has been used for synthesis of food additive antioxidant propyl gallate by direct transesterification of tannic acid. The optimized yield of 86% was obtained by using simultaneously pH tuned enzyme, immobilized on Celite and using the right amount of water in the non aqueous media.

Purification of lysozyme from other hen's-egg-white proteins using metal-affinity precipitation

It was found that the presence of 5 mM Cu(2+) caused precipitation of protein present in hen's egg white to a large extent. About 85% of lysozyme activity remained in the supernatant and the enzyme was purified by approx. 13-fold. A further gel-filtration step on Sephadex G-75 resulted in an overall yield of 80% for the enzyme with 655-fold purification, and showed a single band on SDS/PAGE.

An Integrated Process for Purification of Lysozyme, Ovalbumin, and Ovomucoid From Hen Egg White

This article describes an integrated process for simultaneous purification of lysozyme, ovalbumin, and ovomucoid from hen egg white. The crude egg white extract was passed through a cation exchanger Streamline trade mark SP and the bound lysozyme was eluted with 5% ammonium carbonate, pH 9.0, containing 1 M NaCl after elution of avidin. This partially purified lysozyme was further purified 639-fold on dye-linked cellulose beads. Ovalbumin and ovomucoid did not bind to Streamline SP. Ovalbumin could be precipitated from this unbound fraction by 5% trichloroacetic acid, and ovomucoid was removed from the supernatant by precipitation with ethanol. The yields of lysozyme, ovomucoid, and ovalbumin were 77, 94, and 98%, respectively. All the purified proteins showed single bands on sodium dodecyl sulfate polyacrylamide gel electrophoresis. All the steps are easily scalable, and the process described here can be used for large-scale simultaneous purification of these proteins in the pure form.

Three phase partitioning for extraction of oil from soybean

Three phase partitioning, a method generally used for protein separation, has been evaluated for extraction of oil from soybean. 82% oil was extracted within 1 h using this process which required simultaneous addition of t-butanol (1:1, v/v) and 30% ammonium sulphate to the soybean slurry.

Macroaffinity ligand-facilitated three-phase partitioning (MLFTPP) for purification of xylanase

It is shown that eudragit S-100, a copolymer of methylacrylic acid and methylmethacrylate, undergoes three-phase partitioning. It was found that 95% eudragit S-100 could be recovered as the interfacial precipitate by using 30% (w/v) ammonium sulfate, 1:1 ratio of t-butanol to polymer solution at 40 degrees C. Three-phase partitioning of proteins uses simultaneous addition of ammonium sulfate and t-butanol to precipitate proteins in an interfacial layer separating the aqueous phase and organic solvent. Exploiting the affinity of xylanases towards eudragit S-100, it was possible to purify xylanase from Aspergillus niger; 60% recovery of activity with 95-fold purification could be obtained by this process. The purified enzyme showed A single band on SDS-PAGE. The technique shows promise to develop into a general method that could be termed "macroaffinity ligand-facilitated three-phase partitioning (MLFTPP).

Purification of a bacterial pullulanase on a fluidized bed of calcium alginate beads

Pullulanase from Bacillus acidopullulyticus was purified on a packed bed and a fluidized bed of calcium alginate beads. The binding of enzyme activity to the medium was found to follow Langmuir isotherm pattern. The maximum binding capacity was 1476 U ml(-1) matrix and the dissociation constant was 142 U ml(-1). The dynamic binding capacities at 5% breakthrough in the packed and fluidized beds were 472 U ml(-1) and 644 U ml(-1), respectively. In the packed bed as well as the fluidized bed, an activity recovery of more than 95% with fold purification in the range of 46-59 was observed. The elution with a competitive inhibitor, viz. maltose, and high-fold purification indicate an affinity-based process. The purification process worked equally well with columns of bed volumes of 3.8 and 10 ml.

Magnetite-alginate beads for purification of some starch degrading enzymes

Starch degrading enzymes, viz., beta-amylase, glucoamylase, and pullulanase, were purified using magnetite-alginate beads. In each case, the enzyme activity was eluted by using 1.0 M maltose. beta-Amylase (sweet potato), glucoamylase (Aspergillus niger), and pullulanase (Bacillus acidopullulyticus) from their crude preparations were purified 37-, 31-, and 49-fold with 86, 87, and 95% activity recovery, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed single band in each case.

Three-phase affinity partitioning of proteins

Three-phase partitioning is an elegant way to separate proteins directly from even the large volumes of crude suspensions. It was found that interfacing it with a metal-affinity-based step makes the technique highly selective. As "proof of the concept," soybean trypsin inhibitor was purified 13-fold with 72% recovery. As recombinant proteins (via their polyhistidine tags) and many other naturally occurring proteins are often purified by immobilized metal ion affinity chromatography, the technique described here should prove valuable in purifying biotechnologically important proteins at a large scale.

Immobilized metal affinity chromatography without chelating ligands: purification of soybean trypsin inhibitor on zinc alginate beads

Immobilized metal affinity chromatography (IMAC) is a widely used technique for bioseparation of proteins in general and recombinant proteins with polyhistidine fusion tags in particular. An expensive and critical step in this process is coupling of a chelating ligand to the chromatographic matrix. This chelating ligand coordinates metal ions such as Cu(2+), Zn(2+), and Ni(2+), which in turn bind proteins. The toxicity of chemicals required for coupling and their slow release during the separation process are of considerable concern. This is an important issue in the context of purification of proteins/enzymes which are used in food processing or pharmaceutical purposes. In this work, a simpler IMAC design is described which should lead to a paradigm shift in the application of IMAC in separation. It is shown that zinc alginate beads (formed by chelating alginate with Zn(2+) directly) can be used for IMAC. As "proof of concept", soybean trypsin inhibitor was purified 18-fold from its crude extract with 90% recovery of biological activity. The dynamic binding capacity of the packed bed was 3919 U mL(-1), as determined by frontal analysis. The media could be regenerated with 8 M urea and reused five times without any appreciable loss in its binding capacity.

One-step purification of glucoamylase by affinity precipitation with alginate

It was found that alginate binds to glucoamylase, presumably through the recognition of starch binding domain of the latter. The present work exploits this for purification of glucoamylases from commercial preparation of Aspergillus niger and crude culture filtrate of Bacillus amyloliquefaciens by affinity precipitation technique in a single-step protocol. Glucoamylase is selectively precipitated using alginate as macroaffinity ligand and later eluted with 1.0 M maltose. In the case of A. niger, 81% activity is recovered with 28-fold purification. The purified glucoamylase gave a single band on SDS-PAGE corresponding to 78 kDa molecular weight. The developed affinity precipitation process also works efficiently for purification of Bacillus amyloliquefaciens glucoamylase from its crude culture filtrate, giving 78% recovery with 38-fold purification. The purified preparation showed a major band corresponding to 62 kDa and a faint band about 50 kDa on SDS-PAGE. The latter corresponds to the molecular weight for alpha-amylase of Bacillus amyloliquefaciens.