Advanced Materials Research Vols. 610-613

Abstract: A yellow-brown extract (GLME) was obtained by methanol extraction of powder from Gracilaria lemaneiformis. The methanol extract was further fractionated by liquid-liquid extraction and obtained the four fractions (F-Ⅰ, F-Ⅱ, F-Ⅲ and F-Ⅳ). Growth inhibition of two typical red tide microalgae (Karenia mikimitoi and Alexandrium tamarense) by those fractions and its isolated fractions were investigated. The results showed that crude extract had inhibitory activity against the growth of Karenia mikimitoi and Alexandrium tamarense. Among the four fractions, F-Ⅱ exhibited the strongest effect against the growth of the two red tide microalgae, and the inhibitory effect of Karenia mikimitoi and Alexandrium tamarense by F-Ⅱ at the concentration of 0.35 g/L was 48.8% and 46.7% in day 12, respectively. After additional isolation of F-II with five organic solvents (petroleum ether, petroleum ether:ethyl acetate=1:1, ethyl acetate, ethyl acetate:acetone=1:1 and acetone), the F- II was separated into five fractions of Ⅱ-A, Ⅱ-B, Ⅱ-C, Ⅱ-D and Ⅱ-E on silicon gel column, respectively. The eluant Ⅱ-B andⅡ-C showed the significant growth inhibition activities. The antialgal substances in eluant Ⅱ-B andⅡ-C are identified by comprehensive analysis of UV and HPLC-MS to be chlorogenic acid, hydroxybenzoic acid and vanillic acid. And they significantly inhibited the growth of Karenia mikimitoi and Alexandrium tamarense.

Abstract: Reactive Brilliant Blue KN-R is a typical kind of anthraquinone dye and in common use in textile, dyeing, and printing industries in China, which is difficult to degrade because of its conjugated structure. The decolorization of KN-R was investigated using Ca-alginate immobilized cells of Rhodocyclus gelatinosus XL-1 under anaerobic conditions. For KN-R decolorization by immobilized cells, the suitable pH is 5-8 and the suitable temperature is 25-40 °C. Immobilized cells could decolorize KN-R by co-metabolism in the presence of peptone, and the enhancement of peptone concentration was beneficial for anaerobic decolorization. Metal ions affected the metabolic activity of immobilized cells of R. gelatinosus XL-1. The activity of KN-R decolorization was appreciably increased by Mg²⁺ and Cr³⁺, but severely inhibited by Cu²⁺ and Ag⁺. The maximum absorption peak in visible spectrum shifted from 595 to 453 nm during KN-R decolorization, indicating the formation of the intermediate product.

Abstract: The influences of colloids on nitrogen fixation rate of surface water were studied in the Beibu Gulf of China. The results show that the increment ratios of nitrogen fixation rates in water samples that cultured with colloids added are -96% to 1456% in spring, -9% to 64% in summer, -72% to 122% in autumn and -13% to 216% in winter. The enhancement is most significant in spring. Generally speaking, colloids can promote the nitrogen fixation rates in surface water to some extent.

Abstract: Sludge dewatering is a key part of sludge disposal since it can greatly reduce the volume of sludge and thus improve the treatment effect for handling and disposing. This study investigated the potential benefits of enzymatic pretreatment on activated sludge dewatering with four kinds of enzyme. Capillary suction time (CST) and the solid content after centrifugationwere used to evaluate sludge dewatering. A compression test of paper sludge obtained after treatment was carried out. Besides, some basic properties of activated sludge such as solid content, organic material content, ash content,MLSS,SV30,SVI.The results showed that enzyme additions did not enhanc the dewaterability of the biosolids samples ,but this positively affected filterability of the samples in the compression test. According to these results,enzyme product addition for biosolids samples seems a promising new method of enhancing the performance of mechanical dewatering units in the future.

Abstract: The effects of low and high turbulence on the polysaccharides content and colony formation of Microcystis under different nutrition conditions were studied through a laboratory experiment. The rotation speed of 60rpm and 200rpm was provided to represent the turbulence induced by the wind with a speed of 4.0m/s and 6.5m/s in a shallow lake. Transitory and intermittent high turbulence could stimulate the growth of Microcystis and increase of pH value, but the increase of the pH value was not along with the increase of IC. Under eutrophication, N-limited and P-limited conditions, the salvation ratio increased noticeably (increased from 30% to 60%) because of the increase in rotation speed. High turbulence also makes the colony size be smaller than that with low turbulence. Our results suggested that high turbulence could stimulate the salvation of bound extracellular polysaccharides (bEPS) which was adverse to colony formation of Microcystis.

Abstract: Growth, photosynthesis and the nitrate reductase activity of Ulva pertusa were determined at fluctuating salinity treatments. Compared with the control, SGR of Ulva pertusa were higher at fluctuating salinity treatments. The photosynthetic rates were higher at the fluctuating salinity treatments of 30-25 and 30-20, and lower at the fluctuating salinity treatments of 30-15. Ulva pertusa got higher nitrate reductase activity at fluctuating salinity treatments of 30-20 and 30-15. It demonstrated that Ulva pertusa was able to change the photosynthetic rates and the nitrate reductase activities to adapt to salinity fluctuations.

Abstract: A sensitive and reliable method has been developed for the simultaneous determination of twenty airborne carbonyl compounds in the C1-C10 range. The carbonyls were collected onto solid sorbent coated with pentafluorophenyl hydrazine (PFPH), followed by solvent extraction and gas chromatographic (GC)/mass spectrometric (MS) analysis of the PFPH derivatives. The sorbent is packed into two separate sections in a glass sampling tube. The two-section design allows convenient checking of collection efficiency and breakthrough. The regression coefficient of the calibration curves (R2), limit of detection (LOD), reproducibility (RSD, n=6) and recovery were in the range of 0.995-0.999, 0.15-1.04ng/m3, 7.3-13.2% and 92.7-109.2%, respectively. Compare field test with classical DNPH-HPLC/UV method, good agreement exited between the two methods for lower molecular carbonyls but PFPH method is found to be a better analytical method for determination of high molecular weight carbonyls.

Abstract: The effect of uranium at various concentration on the growth of Chlorella pyrenoidosa and the resistance of Chlorella pyrenoidosa to uranium were investigated in this paper. The results showed that the content of O₂^- and the activity of CAT arose when the concentration of uranium varied at the range of 0.1 to 1.0 mg/L. Uranium had no negative effect on the growth of Chlorella pyrenoidosa at the concentration of 0.1 to 0.5 mg/L, however, had positive effect to some extent. And the rise of the content of O₂^- and the activity of CAT was followed by rapidly returning to the normal level. The uranium at the concentration of 1.0 mg/L prolonged the lag period of the growth of Chlorella pyrenoidosa. The growth of Chlorella pyrenoidosa arose negatively, the content of O₂^- also arose to an unreturnable level and the activity of CAT was lower than CK when the concentration of uraniumm varied at the range of 5.0 to 10.0 mg/L. The uranium biosorption rate by Chlorella pyrenoidosa reached to the highest value of 70.43%when concentration of uraniumm was 0.5 mg/L. Chlorella pyrenoidosa is resistant to uranium of low concentration（≤1.0mg/L）and its biosorption rate is rather high, which indicated good prospect in its future application.

Abstract: Forty-one actinomycetes isolated from sea sand of beach in Weihai were tested using the agar diffusion method, and Staphylococcus aureus was selected as the tested bacteria. Strains with significant inhibitory activity were chosen to ferment in the GS medium, then the supernatant was extracted using ethyl acetate, and the vitro assay of crude extracts was performed. Results indicate: there are eight strains having significant activity, accounting for 31.7% of the total. The suppression of MA27 and MA41 are much significant than the other six strains, and their inhibitory diameter is 15.00±1.14mm and 14.00±2.83mm, respectively. Six extracts of antibacterial metabolites with ethyl acetate were assayed. Three strains (MA27, MA36, SHXF02) have antibacterial activity under the concentration of 2mg/disc, their inhibitory diameter is 29.00±2.64mm, 18.67±2.31mm and 14.33± 0.58mm, respectively.