Heterogeneously Catalyzed Methanolysis of Gmelina Seed Oil to Biodiesel

The heterogeneous catalysis of transesterification of gmelina seed oil to biodiesel is evaluated. The oil was extracted from the seeds with n‐hexane by solvent extraction and characterized to determine its physiochemical properties. Response surface methodology was applied to optimize the effect of process variables on the biodiesel yield. The base‐activated clay catalyst performed as montmorillonite clay with the characteristic property of a Brønsted acid. It has an improved surface area after activation that enhanced its catalytic activity on transesterification reaction. Under optimal conditions, the biodiesel yield was 70.1 %, thus demonstrating that the model predicted well the biodiesel production.     

Statistical optimization of operating parameters of microbial electrolysis cell treating dairy industry wastewater using quadratic model to enhance energy generation

The performance of Microbial electrolysis cell (MEC) is affected by several operating conditions. Therefore, in the present study, an optimization study was done to determine the working efficiency of MEC in terms of COD (chemical oxygen demand) removal, hydrogen and current generation. Optimization was carried out using a quadratic mathematical model of response surface methodology (RSM). Thirteen sets of experimental runs were performed to optimize the applied voltage and hydraulic retention time (HRT) of single chambered batch fed MEC operated with dairy industry wastewater. The operating conditions (i.e) an applied voltage of 0.8 V and HRT of 2 days that showed a maximum COD removal response was chosen for further studies. The MEC operated at optimized condition (HRT- 2 days and applied voltage- 0.8 V) showed a COD removal efficiency of 95 ± 2%, hydrogen generation of 32 ± 5 mL/L/d, Power density of 152 mW/cm² and current generation of 19 mA. The results of the study implied that RSM, with its high degree of accuracy can be a reliable tool for optimizing the process of wastewater treatment. Also, dairy industry wastewater can be considered to be a potential source to generate hydrogen and energy through MEC at short HRT.     

双对苯醌的抗氧化活性分析及其固体发酵条件优化

为探索生物活性未知的双对苯醌（2,7-dihydroxy-3,6,9-trimethyl-9H-xanthene-1,4,5,8-tetraone，DTXT）的抗氧化活性，并提高其发酵产量，考察DTXT的还原力以及对超氧阴离子自由基、羟自由基、1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl，DPPH）自由基的清除效果，在单因素试验基础上，采用响应面法优化了DTXT产生菌瓶生顶孢霉（Acremonium cavaraeanum）CA022菌株的固体发酵培养基。结果表明：在200 μg/mL质量浓度下，DTXT的还原力与芦丁差异不显著，高于VE和2,6-二叔丁基-4甲基苯酚，对超氧阴离子自由基清除率达到67.00%，对羟自由基清除率达到78.83%，对DPPH自由基清除率达到76.53%。通过响应面试验，得到最佳培养基配方为葡萄糖0.773%、硝酸钠0.185%、H3BO3 0.032%、VB1 100 μg/100 g，在此条件下实际获得的DTXT产量为4 150.8 mg/kg，是优化前产量的（2 864.83 mg/kg）1.45 倍。     

Production of a halotolerant lipase from Halomonas sp. strain C2SS100: Optimization by response-surface methodology and application in detergent formulations

The aim of this work was to optimize the production of a new lipase by a halotolerant bacterial strain Halomonas sp. C2SS100, by means of the response-surface methodology (RSM). The process parameters having the most significant effect on lipase production were identified using the Plackett–Burman screening design-of-experiments. Then, Box–Behnken design was applied to optimize lipase activity and the quadratic regression model of the lipase production was built. Indeed, the lipase yield was increased, and the value obtained experimentally (39 ± 2 U/ml) was very close to the rate predicted by the model (40.3 U/ml). Likewise, optimization of parameters by RSM resulted in 2.78-fold increase in lipase activity. These findings provide the first report on lipase production and optimization by a halotolerant bacterial strain belonging to Halomonas genus. Afterward, the biochemical properties of the produced lipase were studied for apply in oil stains removal. The crude lipase showed a maximum activity at 60°C and at pH ranging from 7 to 10. It displayed an important stability at high temperature, pH, and NaCl. Interestingly, this bacterial lipase exhibited a prominent stability toward some commercial solid and liquid detergents after 30 min of incubation at 50°C. The capability of the crude lipase to eliminate stain was ascertained on polycotton fabric pieces stained with lubricating oil. Whether with the addition of hot water alone or of a commercially available detergent, lipase is able to considerably boost the elimination of oil stains. The actual findings highlight the capacity of Halomonas sp. lipase for energy-efficient biocatalytic application.     

Recent activities in the field of Nuclear Operational Management and Nuclear Safety Engineering

Recent activities in the field of Nuclear Operational Management and Nuclear Safety Engineering, the studies related to risk analysis methodology, design, and operational management, physical phenomena, and emergency preparedness and nuclear security, have been progressed. Especially, ‘risk analysis methodology’ and ‘design and operational management’ are the main categories of the field, in which more than half of published articles on Journal of Nuclear Science and Technology are related to these categories.     

Predicting employee information security policy compliance on a daily basis: The interplay of security-related stress,emotions, and neutralization

We conceptualized security-related stress (SRS) and proposed a theoretical model linking SRS, discrete emotions, coping response, and information security policy (ISP) compliance. We used an experience sampling design, wherein 138 professionals completed surveys. We observed that SRS had a positive association with frustration and fatigue, and these negative emotions were associated with neutralization of ISP violations. Additionally, frustration and fatigue make employees more likely to follow through on their rationalizations of ISP violations by decreased ISP compliance. Our findings provide evidence that neutralization is not a completely stable phenomenon but can vary within individuals from one time point to another.     

响应面法优化超临界二氧化碳萃取蓝圆鲹鱼油工艺研究

利用超临界二氧化碳萃取技术提取蓝圆鲹鱼油,采用单因素实验考察萃取温度、萃取压力及萃取时间对蓝圆鲹鱼油得率的影响,并采用响应面优化Box-Behnken设计优化萃取工艺。结果表明:最佳萃取工艺条件为萃取温度49℃、萃取时间140 min、萃取压力20 MPa,在此条件下蓝圆鲹鱼油得率为18.45%,提取率达88.91%。蓝圆鲹鱼油经气相色谱-质谱法(GC-MS)分析鉴定出17种脂肪酸,不饱和脂肪酸含量为55.70%,其中二十碳五烯酸(EPA)与二十二碳六烯酸(DHA)总含量为16.64%。超临界二氧化碳萃取技术应用于蓝圆鲹鱼油的提取具有一定的理论价值和经济效益。     

黑果腺肋花楸中花色苷超声辅助提取工艺优化研究

目的优化超声辅助提取黑果腺肋花楸中花色苷工艺的方法。方法在单因素的基础上,研究提取温度、液料比和提取时间对花色苷提取率的影响,并利用响应面法对花色苷的提取条件进行优化。结果黑果腺肋花楸中花色苷提取的最佳工艺条件为:乙醇溶液(含0.5%的乙酸)浓度为40%,提取温度为43℃,超声时间为23 min,料液比为89:1(V:m),此条件下,黑果腺肋花楸中花色苷提取得率为(0.79±0.010)g/100g。结论本方法可以快速有效地提取黑果腺肋花楸中的花色苷。     

响应面试验优化双酶酶解法制备鱼鳞抗菌肽工艺及其抑菌性能分析

采用双酶酶解法制备鱼鳞抗菌肽,进行酶筛选并通过响应面法优化酶解条件;通过葡聚糖凝胶G-25分离纯化酶解液,研究有效抑菌组分对不同菌的最小抑菌浓度(minimum inhibitory concentration,MIC)。结果表明,当采用碱性蛋白酶结合酸性蛋白酶分步酶解鱼鳞,底物质量浓度为30 g/100 m L时,最适酶解条件为碱性蛋白酶在pH 9.5时首次酶解,酶解时间62 min,酶解温度55℃;酸性蛋白酶在pH 3.0时再次酶解,酶解时间3 h,酶解温度34.4℃。此条件下制备的酶解液对副溶血性弧菌的抑菌圈直径为27.72 mm,与预测值基本相符。酶解液经层析后,其抑菌性G2组分对假单胞菌和希瓦氏菌的MIC为1.56μg/m L,对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、沙门菌及副溶血性弧菌的MIC为6.25μg/m L。可见,双酶酶解法制备的鱼鳞抗菌肽具有较强的抑菌性。