Advanced Materials Research Vols. 550-553

Abstract: The lipoxygenase (LOX) in grass carp can catalyze the oxidation of polyunsaturated fatty acids even their esters, resulting in rancidity deterioration of grass carp and its products during the process and storage. Preliminary purification, quantitative determination and distribution of grass carp muscular LOX were investigated in the present study. LOX activity of the grass carp muscle was measured to be 35.17 KU/g and its molecular weight was 95.71 kDa identified by SDS-PAGE. Using previously reported extraction methods such as twice salting-out and once dialysis, the LOX protein content in the crude muscular LOX extraction is about 28%. When salted with graded saturation of ammonium sulfate, we found once salting-out was enough for LOX extraction and the effective percentage saturation of ammonium sulfate for LOX extraction was 40%. Under this condition, the LOX protein content in the crude muscular LOX extract was doubled. The LOX distribution in fish was gradually increased from skin and muscle, gill, viscera to blood, which indicates that it is very important to remove the viscera and bleed fish completely during fish product processing to decrease the risk of lipid oxidation caused by LOX.

Abstract: In order to solve the indoor air pollution caused by formaldehyde, an ornamental plant of Kafirlily was used to purify the formaldehyde in this paper. By testing the absorbing effect on ornamental in the transparent airtight cabin, the physiological and biochemical parameters such as leaf hurt index and peroxidase (POD) activity were determined. The experimental results showed that the Kafirlily can decline the formaldehyde concentration to a certain degree, the leaves were hurt little, and the POD activity changed markedly. The experiments can indicate that Kafirlily can purify the indoor formaldehyde in certain concentration range with strong tolerant ability and high POD physiological stress responses.

Abstract: In order to investigate the characterizations of skin adsorption material (SAD) prepared from skin of corn stalks by High Boiling Solvent treatment, neutral proteinase and maltogenic amylase were selected as adsorbate to assess its potential applicability for enzyme immobilization. The structure of SAD and Skin were compared by FT-IR and XRD. The characterizations of the adsorption of the different enzymes onto SAD were studied. The isotherm of the maltogenic amylase was found to be linear with the Freundlich equation, and proteinase was found to be linear with the Langmuir equation in the studied concentration range. SAD could be applied the bio-active material and Skin to prepare SAD.

Abstract: A bioflocculant M-1 produced by Enterobacter sp. EP3 was investigated with regard to its flocculanting characteristics and mechanism. 2.0 mg/l M-1 showed the maximum flocculating activity of 96% in 5.0g/l Kaolin suspension containing 8mM CaCl₂ and that its flocculating activity was more than 80% in a wide pH range (4.0-12.0). Chemical analyses indicated that the biopolymer M-1 was mainly a polysaccharide, mainly consist of rhamnose and glucose with a molar ratio of 9:1. Infrared spectrophotometry showed the presence of carboxyl, hydroxyl and methoxyl groups in M-1 molecular. Flocculation of Kaolin suspension with M-1 acted as a model to explore the flocculating mechanism in which bridging mediated by Ca²⁺ was proposed as the primary action based on the experimental observations.

Abstract: The effect of microwave-assisted NaOH solution to pretreat rice husk was studied with RSM (Response Surface Method). When NaOH concentration; microwave power; irradiation time and solid-to-liquid ratio, are 1.5%; 650 w; 16 min and 1:12 respectively, the rice husk which are treated under such conditions can be hydrolyzed by the enzyme to get 56.24% sugars.

Abstract: To help meet the challenge of 1-Deoxynojirmiycin (DNJ) manufacture from microbial fermentation, optimal condition for the fermentation has attracted substantial research interest. In the case, mix strategy was carried out to cultivate mulberry rhizosphere Bacillus Subtilis BJ-B121 (DNJ producing strain), Rhizopus spp.BJ-F13 and Aspergillus niger BJ-F8 according to the plate dual culture assay and inhibitory activity assay in vitro. We characterized mixed cultivation of Bacillus Subtilis BJ-B121 and mulberry rhizosphere microorganisms on the basis of biochemical data. Rhizosphere soil microorganisms may interact with each other and lead to improvement of DNJ production. Campared with mono culture, the glucose consumption and DNJ production were efficient. DNJ production was improved by 26-32% in mixed cultivation, 100 μg/mL and 308 μg/mL extra DNJ production were obtained. In addition, DNJ did not affect the growth of the mixed cells.

Abstract: Two extracellular alkaline polygalacturonases from extracts of liquid cultures of Paenibacillus polymyxa 20185 were purified by gel filtration chromatography to homogeneity as judged by SDS-PAGE. The purified alkaline polygalacturonases (PG1 and PG2) had a similar molecular weight of 65 kDa, exhibited maximal activity at 50°C with pH 10.0, and were stable in alkaline conditions. The purified alkaline polygalacturonases activities were enhanced in the presence of Mg²⁺, and were resistant to inhibition by Mn²⁺, Zn²⁺ and Cu²⁺. Michaelis-menten constants of PG1 and PG2 were found as 3.6mg/mL and 3.5mg/mL, respectively.

Abstract: Raw cassava starch was treated with α-amylase and amyloglucosidase in aqueous solution under annealing condition to obtain starch granules with rough and porous surfaces. Many different pits and pores formed by the activity of the enzymes on the surface granules and were observed by scanning electron microscopy (SEM). The obtained starch granules with rough surfaces were mechanically blended with poly(butylenes adipate-co-terephthalate)(PBAT) at different ratios by using a single screw extruder. The results showed that the samples comprised of enzymatically treated starch blends had higher elongation than those comprised of untreated starch blends. At 10% starch content, the treated starch/PBAT blend had about 37.55% more elongation than the untreated starch/PBAT blend. This resulted in the improved compatibility of the starch granules and PBAT matrix in the blends as confirmed by SEM.

Abstract: To improve the miscibility of native rice starch granules and poly(butylene adipate-co-terephthalate)(PBAT), rice starch was hydrolyzed by a mixture of α-amylase and amyloglucosidase. The obtained porous rice granular starch was then mechanically blended with PBAT by single screw extruder. Many pits and holes on the surface of starch granules were observed by scanning electron microscopy (SEM). The rough surface of the rice starch granules improved the compatibility of the polymers in the blends, which consequently increased the tensile strength and the elongation at break. In addition, SEM also revealed that the porous granules were homogeneously distributed in the polymer matrix with no appearance of gaps.

Abstract: In this study, ultrasonic-microwave assisted synthesis of the hydroxypropyl Dioscorea alata starch was investigated and optimized. Under the irradiation of ultrasonic-microwave, Dioscorea alata starch was added to the reactor as raw material, and five factors (propylene oxide, sodium hydroxide, anhydrous sodium sulfate, microwave treatment time and microwave power) that influence the preparation of hydroxypropyl Dioscorea alata starch were analyzed using single-factor and orthogonal experiment methodology. Characteristic of products was evaluated by determining their molar substitution (MS). During the experiment , ultrasonication power was fixed at 50 w. The optimum conditions were determined as propylene oxide 12% (w/w), sodium hydroxide 1.0% (w/w), anhydrous sodium sulfate 8% (w/w), microwave irradiation time 110 s and microwave power 80 w. The optimal condition of the product gives a MS value at 0.82. The hydroxypropyl Dioscorea alata starch paste shows higher light transmittance(25.5%) and solubility in cold water, lower gelatinization temperature(59°C) in comparison to native starch. Compared with conventional process, the reaction time was significantly shortened by ultrasonic-microwav