Advanced Materials Research Vols. 726-731

Abstract: The screening and cellulase production study of cellulase production microorganisms was the basis for the purpose. CMC medium was used in this study to isolate cellulose degrading bacteria. As a result, six strains were obtained from the soil, one strains of which Streptomyces-2 had higher cellulase activities in the Liquid fermentation medium of Straw, which was 3.230U/mL. By morphological observation and physiochemical analysis, it was primarily classified as Streptomyces sp which study less. It provides a new species for the cellulase application in the field of bio-chemical. At the same time it provides a new way for the cellulase applied to microbial conversion for low-rank coal in the future.

Abstract: 25 strains of Lactic Acid Bacteria were selected to carry on aerobic cultivating test. It was found that LD33 and 1031 could undergo respiration in the present of heme. compared with the original strain cultivated under fermentative conditions , both its biomass and pH increased. After 45 days storaged at 4°C, the strain LD33 cultivated under fermentative condition was less than 10CFU/mL, while the viable cell count of strain cultivated under respiratory condition was remain 10⁸ CFU/mL. Aerobic respiratory metabolism shift occurred in the early exponential growth was indicated by the growth curve and pH curve.

Abstract: Using DTAF fluorescent staining technique, the number of bacteria and the distributions of ΣPAHs in two different drilling vertical depths of a field contaminated by PAHs are counted and analyzed. The result showed that the distributions of the number of bacteria and the ΣPAHs in the vertical depth have obvious corresponding relations, and the higher the ΣPAHs is, the more the number of bacteria would be.

Abstract: The aim of this study was to investigate the characteristic of color changes in Thompson seedless grape during drying at 30°C, 35°C and 40°C air temperatures. The CIE LAB color system was used to measure the surface color of the grapes. It was found that browning began at middle period of drying, where parameters L* and b* decreased and parameter a* increased during drying. Color changes during browning process were described as a first-order kinetic model, where the activation energies for the parameters L*, a*, b*, and total color difference were respectively 40.19, 24.29, 35.43, and 39.46 kJ·mol¹.

Abstract: Yellow River Delta has a special status of coastal wetland research in China. The microbial community characteristics such as community structure, activity and size in the wetland were investigated in the modern Yellow River Delta of Shandong Province. The aim was to find the effect of salinity on the microbial community. There was a significant negative linear relationship between soluble salt content and the total number of microbes, overall microbial activity, and diversity of culturally viable microbes. Differences of the soil bacterial community in different depths were monitored using the terminal restriction fragment length polymorphism (T-RFLP) and clone library analyses. In a word, these results indicate that higher salinity and deeper depth resulted in a smaller, more stressed microbial community which was less active and diverse .

Abstract: This research investigated the effect of media fill ratio on membrane fouling in moving bed bioreactors-membrane bioreactor. The results shown the high removal of ammonia and COD, despite the membrane fouling conditions were really different in two bioreactors. The total modified fouling index (MFI) of IFAS 3000 was three times than MFI of IFAS 1500, and the soluble microbial products (SMP) present in the mixed liquor played an important role in the membrane fouling. No more correlation was found between the extracellular polymeric substances (EPS) concentration and fouling, and the average SMP of IFAS 3000 was higher than IFAS 1500. The carbohydrate of SMP occupied high fraction in all reactors. Large molecular weight (MW) components constituted the major fraction of EPS and SMP. The results indicated that higher media fill ratio can decrease membrane fouling effectively.

Abstract: By analyzing the different crop interplanting test in chestnut forests, the results show that soil nitrate nitrogen, ammonium nitrogen and available phosphorus fell in October when intercropped plants, this may be related to the growth of chestnut trees absorb nutrients and microorganisms in the soil. The results of this study show that interplanting different plants had an impact on soil microbial biomass carbon and microbial biomass phosphorus. Microbial biomass carbon turnover rate in the order: ryegrass> clean tillage> natural grass> Alfalfa> flat Agropyron> soybean; turnover rates of soil microbial biomass phosphorus in the order: clean tillage> Alfalfa> ryegrass natural grass> soy> flat crested wheatgrass.

Abstract: The solid phase microextraction (SPME) uses a fine fused silica fiber coated with a thin layer to extract directly analytes from samples. The silanol group at silica surface, Si-OH, can be acidic, and may exsit as an Si-O^- group at certain pH level, and silica backbone may have cation exchange secondary interactions, attracting cationic or basic analytes of interest. It is necessary that pH optimum for water sample should be adjusted. A 7 μm nonpolar polydimethylsiloxane coating was used to extract polycyclic aromatic hydrocarbons (PAHs) in environmental water such as river water, rainwater, ground water, tap water and accumulated water on farm. The influence of pH on extraction of PAHs in water was investigated, and the optimum pH 6 was affirmed. A GC/MS was used to detect PAHs with the selective ion-monitoring mode. The optimum thermally desorption time of PAHs from the fiber coating was 5 minutes. The precision and the recoveries were ranged from 4 to 13 % RSD and 71 to 114%, respectively, depending on PAHs species. The trace levels of PAHs in environmental water were detected between 0.4~15.4 ng/ml.

Abstract: Bismuth titanate powders have been prepared by the citric-combustion method using bismuth nitrate and tetrabutyl titanate as the starting materials, and the effect of sintering temperature and the ratio of bismuth to titanium on their structure and photocatalytic activity was studied. The powders were characterized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The photocatalytic properties of the samples were probed by using the methyl blue as simulated contaminants. The results showed that bismuth titanate powder prepared at 873K has the best photocatalytic activity.

Abstract: Eupatorium adenophorum spreng is a global invade weed but is also an excellent enrichment plant for heavy metal. However, the characteristics of physiology is still not clear under heavy metals stress. The research focused on changes of plant height, basal diameter, leaf length and width, POD activity, protein content, chlorophyll content, electric conductivity and MDA content in different Pb concentration. The results showed that all indexes were descend in different extent in Pb condition, especially part indexes, such as plant height, soluble and insoluble protein and POD activity, were significant difference with control. But, combined treatment condition (500-2000 mg/kg) with these indexes Eupatorium adenophorum spreng showed the better characteristics to as a pioneering plant for ecological restoration of some serious mining wasteland.