Papers by Keyword: Enzymatic Activity

Abstract: To discuss the relationship between the effect on soil improvement, soil phosphatase activity and catalase activity by applying biogas slurry, the soil was applied on biogas slurry and pig manure respectively which was from demonstration base of ecological mulberry field at Rongchang, the soil enzymes and nutrients factor were determined and analyzed at different times. The results show that biogas slurry and pig manure can increase the content of soil organic matter, TN, TP, available nitrogen, available phosphorus and available potassium, and improve the activity of soil enzymes. It can significantly improve the activity of acid phosphatase by applying biogas slurry, and have certain effect on alkaline and neutral phosphatase activity; it can effectively improve the soil catalase activity for long-term using.

Abstract: The study was conducted to investigate the effects of nano-sized titanium dioxide (nTiO2 )on the growth and biophysical characteristics of Chlorella sp.. Chlorella sp. was cultured in HB-4 medium and exposed to 7 levels(0,1,5,10, 20, 40 and 80mg/L)of nTiO2.The results showed that EC50 of nTiO2 was 26.52 mg/L after 96-hr exposure. In 5 levels (0,10, 20, 30 and 40mg/L)of nTiO2 after 96-hr exposure, the content of Chl-a and the soluble protein was reduced with the increasing concentrations. Because of nTiO2 caused the increase of permeability of Chlorella sp.'s membrane, some soluble materials got out of Chlorella sp.'s cell, such as polysaccharide.The value of conductivity and polysaccharide content was increased with concentrations. When the concentrations of nTiO2 were higher than 20mg/L, the physiological function of Chlorella sp. was inhibited obviously, and the activity of peroxidase and dehydrogenase decreased. As a result, there was the potential harm to the aquatic environment by using nTiO2.So the toxicity of nTiO2 and the mechanism of aquatic lives deserved special concern.

Abstract: Vermicomposting experiments were conducted to study the effects of Chinese medicine residue at optimal moisture content on growth and fecundity of Eisenia foetida in laboratory. Under the conditions of different pH and inoculation density, the treatment effects were determined through analyzing the changes of Chinese medicine residue properties. The results showed that the optimal pH for Eisenia foetida was 6.5, and that 40 earthworms per 1kg residues was the most appropriate density for unfermented Chinese medicine residue. Compared with the control, the earthworm treatment could significantly accelerate organic matter mineralization and promote the degradation of materials. After vermicomposting, pH value of the residue was close to neutral, and total N and the enzyme activities were both significantly increased. While the value of C/N and TOC were both reduced. These results suggested that vermicomposting was a better way for Chinese medicine residue treatment, the rate of quantitative reduction and the treatment efficiency were 73.54% and 44.52%, respectively.

Abstract: Purpose To research out a suitable method for the determination of enzymatic activity for β-glucan synthase. Methods According to the methods for the determination of ΒGS in current reports, taking Grifola frondosa as material, a suitable method for the determination of enzymatic activity for ΒGS was researched out. ΒGS was isolated from the mycelium of Grifola frondosa. Taking glucose as substrate, ΒGS activity was reflected by the consumption of glucose. Consumption of glucose was measured by 3,5-dinitrosalicylic acid (DNS) method, the standard curve for glucose content measurement was plotted by determining absorbance values of different glucose concentrations at 540nm. One unit of ΒGS corresponds to the amount of enzyme which incorporated 1μg glucose into β-glucan in 1 minute. The optimum pH and temperature of the determination of enzymatic activity for ΒGS was determined respectively by carrying out the enzyme assay at different pH levels and temperatures. Results The method for the determination of enzymatic activity for ΒGS was a suitable, correct and usable method which can be popularized widely. The regression equation of the standard curve for glucose content measurement was y=0.0008x-0.0247, R2=0.9996. The optimum pH of the determination of enzymatic activity for ΒGS was pH=5.0 and the optimum temperature was 15°C. The suitable determination process for β-glucan synthase enzymatic activity is as follows: 1.0ml of enzyme was added in a test tube followed by 1.0 ml glucose (1.0mg/ml), and then the pH level was adjusted to 5.0. The test tube was incubated at 15°C for 10 minutes. Later, DNS reagent (1.5ml) was added to the test tube kept in boiling water for 5 minutes and cooled in water. A blank was prepared (2.0ml distilled water and 1.5ml DNS solution). Each solution was fixed the volume to 25ml, the color intensity was estimated at 540 nm using spectrophotometry. Conclusion A method for the determination of enzymatic activity for β-glucan synthase was researched out by taking Grifola frondosa as material, and it can be widely extended and applied by its characteristics of simple, rapid, high sensitivity and low cost.

Abstract: Physicochemical and biological properties were studied during the forced aeration composting of digested sludge and sawdust under ambient temperature between 9 and 15°C. The temperature above 55°C in the core of composting pile kept for 5d during the whole composting process. Total organic carbon and moisture content obviously declined with the increase of composting time, and the content of NO3--N increased. pH, electrical conductivity, NH4+-N, cellulose and urease activities originally increased and then declined. The germination index was 82.82% on day 35. The research results showed that forced aeration composting of digested sludge and sawdust under low ambient temperature could meet the demand of mature on day 35.