جستجوی مقالات مرتبط با کلیدواژه « enzyme assay » در نشریات گروه « زیست شناسی »

Temperature is one of the most important factors in maintaining the quality of stored horticultural products, which affect physiological and biochemical processes. There is no report on the efficacy of lavender essence in regulating the antioxidant capacity of cold-stored food products. The aim of present study was to investigate different concentrations of Lavender essence on improving biochemical quality of cold stored radish tuber. Greenhouse cultivated radishes were stored under cold condition after essence (., 1.56, 3.13, 6.25, 12.5 and 25 ppm) dipping treatment. Nine days’ evaluation of tuber characteristics (days 3, 6 and 9) indicated that low temperature decreased L*, a*, protein and DPPH characteristics and increase in b*, MDA, protease, catalase, peroxidase and poly phenol oxidase activities. Lavender essence caused a balance in the oxidant / antioxidant system through reduction in peroxidase and poly phenol oxidase activity and decrease in MDA content. The essence concentrations of 12.5 and 25 ppm were most effective.

Moderate halophiles are excellent sources of enzymes that are not only salt- stable, but also have optimal activities at a wide range of pH and temperature. The aim of this study was the isolation of moderately halophilic protease-producing bacteria from saline soils in Alborz province.
Material & Screening of the protease- producing halophilic bacteria was carried out by skim milk agar containing 5% NaCl. Enzyme assay was investigated by the colorimetric method and the effect of various parameters such as temperature, pH, and different NaCl concentrations on enzyme activity were assessed. Identification of the isolates was carried out by biochemical as well as molecular methods.
A total of 11 halophilic strains with proteolytic activity were isolated among which the strain B8 with higher clearance zone on skim milk agar and 3.2 Unit/mL supernatant activity was chosen for further analysis. The enzyme exhibited its optimal activity at the temperature of 40◦C, pH of 7.5 and NaCl concentration of 0-0.5 M, although at higher salinities (up to 3 M) activity was still remained. The enzyme was active at a broad pH range, keeping 60% of its activity at pH of 9.5. Phylogenetic analysis based on 16S rRNA gene sequencing identified the isolate as Halomonas. It was deposited in GenBank, with the name of Halomonas sp. strain HM_NG2.
These findings suggest that the protease secreted by the isolate of this study could be a good candidate for biotechnological applications due to its moderate thermo-stability and halloalculophytic properties.