Three-phase partitioning (TPP) was used to purify and recover catalase from potato crude extract. The method consists of ammonium sulfate saturation, t-butanol addition, and adjustment of pH, respectively. The best catalase recovery (262 %) and 14.1-fold purification were seen in the interfacial phase in the presence of 40 % (w/v) ammonium sulfate saturation with 1.0:1.0 crude extract/t-butanol ratio (v/v) at pH 7 in a single step. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the enzyme showed comparatively purification and protein molecular weight was nearly found to be 56 kDa. This study shows that TPP is a simple, economical, and quick method for the recovering of catalase and can be used for the purification process.

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The characterization of the hydrogel was performed using Fourier‐transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. Purified Bacillus pumilus Y7‐derived alkaline protease was immobilized in Poly (vinylimidazole)/clay (PVI/SEP) hydrogel with 95% yield of immobilization. Immobilization decreased the pH optimum from 9 to 6 for free and immobilized enzyme, respectively. Temperature optimum 3°C decreased for immobilized enzyme. The Km, Vm, and kcat of immobilized enzyme were 4.4, 1.7, and 7.5‐fold increased over its free counterpart. Immobilized protease retained about 65% residual activity for 16th reuse. The immobilized protease endured its 35% residual activity in the material after six cycle's batch applications. The results of thermodynamic analysis for casein hydrolysis showed that the ΔG≠ (activation free energy) and ΔG≠E‐T (activation free energy of transition state formation) obtained for the immobilized enzyme decreased in comparison to those obtained for the free enzyme. On the other hand, the value of ΔG≠ES (free energy of substrate binding) was observed to have increased. These results indicate an increase in the spontaneity of the biochemical reaction post immobilization. Enthalpy value of immobilized enzyme that was 2.2‐fold increased over the free enzyme indicated lower energy for the formation of the transition state, and increased ΔS≠ value implied that the immobilized form of the enzyme was more ordered than its free form.

A carboxymethylcellulose (CMC)-degrading bacterium was isolated from soil, identified as Bacillus methylotrophicus according to the physiological properties and analyses of 16S rRNA and a partial sequence of the gyrase A (gyr A) gene, and named as B. methylotrophicus Y37. The CMCase enzyme was purified to homogeneity by 20.4-fold with 21.73% recovery using single-step hydrophobic interaction chromatography and biochemically characterized. CMCase showed a molecular weight of approximately 50 kDa as determined by SDS-PAGE. The activity profile of the CMCase enzyme exhibited optimum activity at 45 • C and pH 5.0. The activity was highly stable at alkaline pH levels. More than 90% of the original CMCase activity was maintained at relatively high temperatures ranging from 55 to 65 • C. The enzyme activity was induced by Ca 2+ , Cd 2+ , Co 2+ , K + , Mg 2+ , and Na 1+ , whereas it was strongly inhibited by phenylmethanesulfonyl fluoride and iodoacetic acid. The enzyme tolerated Hg 2+ up to 10 mM and presented hydrolytic activity towards glucan, filter paper, laminarin, and CMC but not o-nitrophenyl β-D-galactopyranoside. Kinetic analysis of the purified enzyme showed K m and V max values of 0.19 mg mL −1 and 7.46 U mL −1 , respectively. The biochemical properties of this CMCase make the enzyme a good candidate for many industrial applications.

This study aimed to investigate the effects of drought stress on Amsonia orientalis, an endangered ornamental plant with a limited natural distribution in Europe. Effects of polyethylene glycol (PEG)-mediated drought stress (-0.15, -0.49, -1.03 and -1.76 MPa osmotic potentials) were tested on in vitro cultures. In general, root lengths and numbers, total protein, chlorophyll a and carotenoid contents were negatively influenced at elevated levels of the stress factor. The successive decrease in the tested osmotic potentials resulted in gradually higher H2O2, malondialdehyde (MDA) and proline contents. Activities of the antioxidant enzymes, peroxidase (POD) and catalase (CAT), were found to be enhanced in response to the decreasing osmotic potential tested, whereas increased superoxide dismutase (SOD) activity was observed at the -0.15 MPa osmotic potential. Strong activation of POD enzymes under drought stress suggests that POD enzymes might have a major role in regulating the H2O2 content, while CAT has only a supplementary role in A. orientalis. These results indicated that although A. orientalis is susceptible to long-term drought, the species may survive during mild drought stress because the development of the plant was not totally inhibited but only limited. Nevertheless, the species should be introduced to well-irrigated lands, after evaluation of the soil’s water status, in order to ensure the continuation of its generations.