Emerging applications of green coconut: A promising lignocellulosic biomass

Waste accumulation is a grave concern and becoming a transboundary challenge for environment. During Covid-19 pandemic, diverse type of waste were collected due to different practices employed in order to fight back the transmission rate of the virus. Covid-19 was proved to be capricious catastrophe of this 20th century and even not completely eradicated from the world. The havoc created by this imperceptible quick witted, pleomorphic deadly virus can't be ignored. Though a number of vaccines have been developed by the scientists but there is a fear of getting this virus again in our life. Medical studies prove that immunity drinks will help to reduce its reoccurrences. Coconut water is widely used among all drinks available globally. Its massive consumption created an incalculable pile of green coconut shells around the different corners of the world. This practice generating enormous problem of space acquisition for the environment. Both the environment and public health will benefit from an evaluation of quantity of coconut waste that is being thrown and its potential to generate value added products. With this context, present article has been planned to study different aspects like, coconut waste generation, its biological properties and environmental hazards associated with its accumulation. Additionally, this review illustrates, green technologies for production of different value added products from coconut waste.     

Racemic,R-, and S-tebuconazole altered chitinase and chitobiase activity of Daphnia magna

Tebuconazole is a chiral trizole fungicide and widely used in many crops for controlling disease. Tebuconazole is potential toxic to some aquatic organisms but relative information of its isomers is scarce. To detect the endocrine disrupting effects and difference of rac-, R-, and S-tebuconazole, the chitinase activity in Daphnia magna and chitobiase activity in each test medium were used as biomonitors after a 14-day exposure. Results showed that chitinase activity was significantly reduced by rac-, R-, and S-tebuconazole. The chitobiase activity in the test medium was reduced by rac- and R-tebuconazole before day 10, and only one peak was observed at day 10 or day 12 compared with two obvious peaks in the control group (days 6 and 12). S-tebuconazole delayed and reduced the reproduction of D. magna, but did not delay the first chitobiase activity peak, whereas the second peak could not be characterized as the exposure concentration and time increased. Compared with chitinase activity, chitobiase activity can still be used as a rudimentary model for identifying molt-interfering xenobiotics, and further studies should focus on the analysis of correlations between these parameters.     

中国大气中重金属钒的排放特征

化石燃料原油和原煤的燃烧、含钒矿石的开采和冶炼是大气中重金属钒的主要来源。文章利用重金属钒的排放系数分析了中国1978-2010年人为过程释放到大气中重金属钒的总量和行业重金属钒的排放,预测了2020年和2030年中国大气中重金属钒的排放量。结果表明,自1978年以来,中国钒的排放量增加了4倍,中国2010年人类活动向大气排放的重金属钒总量达3.18万吨,约占世界总量的12%。原油燃烧释放到大气中的钒约占总量的85%,煤炭燃烧的排放量占10.5%,其中工业耗油向大气中释放重金属钒的比例从1980的71%下降到2008年的42%,总量从3 721 t增加至9 361 t;交通运输行业从10%上升到36%,总量从547 t增加至7 967 t;其它行业(农林牧渔水利业、批发零售业和住宿餐饮业、生活消费)基本维持在20%左右,总量从986 t增加至5 052 t。因此,应加强大气中钒的监测和管理,预防大气钒污染事件的发生。     

环氧化PVA载体固定漆酶的最佳工艺条件研究

在T=35℃,HAc-NaAc缓冲溶液pH为4的条件下,用环氧化PVA载体对漆酶进行固定化,固定后酶活为游离酶活的95%。用该固定化漆酶处理制浆造纸废水,反复使用6次后,酶活仍保持为初始酶活的45%,且每次COD去除率在40%以上,处理后的废水BOD增大了50%,废水可生化性得到很大提高。     

离子液体1-丁基-3-甲基咪唑氯盐对斜生栅藻的毒性效应

按照毒性试验标准方法研究了不同浓度离子液体1-丁基-3-甲基咪唑氯盐([BMIM]Cl)对斜生栅藻的影响,测定了半数抑制浓度(IC50)、叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性以及藻细胞通透性的变化,观察了80mg/L[BMIM]Cl处理96h对藻细胞的影响.结果表明:[BMIM]Cl对斜生栅藻生长具有抑制作用,随着浓度的增大抑制率增加,叶绿素含量下降, 48h IC50、72h IC50和96h IC50分别为103.77、76.44和68.49mg/L.藻细胞对[BMIM]Cl有一定的氧化应激反应,CAT和SOD活性随[BMIM]Cl浓度升高而降低.[BMIM]Cl对藻细胞的细胞膜有一定程度的破坏作用,藻细胞通透性随浓度升高而增大,同时藻细胞的超微结构受到了[BMIM]Cl的影响,造成质壁分离,叶绿体片层断裂,线粒体嵴数量减少.     

高效木薯渣分解复合菌群RXS的构建及其发酵特性研究

从富含腐烂纤维质的环境中取样,通过以木薯渣及滤纸为碳源的蛋白胨纤维素培养基不断地富集培养,构建了一组高效稳定的纤维质分解复合菌群.考察了该复合菌群对不同纤维质底物的分解性能及其在木薯渣水解过程中主要参数的变化.研究发现该复合菌群对滤纸、脱脂棉、微晶纤维素、麦秸秆和木薯渣等原料均能够进行有效的降解.在该复合菌群应用于木薯渣的水解过程中,监测发现纤维素酶、半纤维素酶、果胶酶等关键酶的酶活力分别在第2～3 d达到最大值34.4、90.5和15.8U;经过10 d的发酵后,木薯渣中的纤维素、半纤维素及木质素分别降解了79.8%、85.9%和19.4%,且木薯渣的失重高达61.5%;此外,代谢产物主要是乙酸、丁酸、己酸和甘油;而溶解性COD、总糖和总挥发酸的变化表明第2 d时木薯渣的水解率最高.上述结果表明,该复合菌群能够有效地水解木薯燃料酒精生产过程中的废弃物木薯渣,并有望用于木薯渣高效沼气发酵的前处理中.     

东湖沉积物中dNaR活性和硝酸盐还原菌的垂向分布

测定了武汉东湖污染负荷不同的3个点位(污染负荷为3号2号1号)柱状沉积物中异化性硝酸还原酶(dNaR)活性以及硝酸盐还原菌数量、TOC、TN、NO3--N的垂向变化,分析了dNaR活性与硝酸盐还原菌数量、TOC、TN、NO3--N的相关性.结果表明,不同点位沉积物中dNaR活性不同,污染负荷最高的3号点位dNaR活性最高,污染负荷最低的1号点活性最低.不同点位沉积物中dNaR活性在垂向分布上具有相似特征:0～15cm沉积物中活性较大,15cm以下随着深度的增加,酶活性迅速降低.硝酸盐还原菌数量在垂向分布上随着深度的增加而减小.dNaR活性与TOC、TN不具有相关性,而与NO3--N呈正相关(P0.05);dNaR活性与硝酸盐还原菌数量呈显著性相关(P0.01).     

Modelling sulphate-enhanced cadmium uptake by Zea mays from nutrient solution under conditions of constant free Cd2+ ion activity

A controlled hydroponic experiment was undertaken to investigate Cd uptake in relation to the activity of Cd species in solution other than the free ion (Cd²⁺) by maintaining a constant Cd²⁺ activity under variable SO₄₂⁻ and Cl⁻ concentrations exposed to maize (Zea mays var. Cameron) plants. The objectives of these experiments were: (1) to distinguish and quantify the different uptake rates of free and inorganic-complexed Cd from nutrient solution, and (2) to model the uptake of Cd by maize with a Biotic Ligand Model (BLM) in a system which facilitates the close examination of root characteristics. Results of the current experiments suggest that, in addition to the free ion, CdSO₄⁰ complexes are important factors in determining Cd uptake in nutrient solution by maize plants. Higher nominal SO₄²⁻ concentrations in solution generally resulted in a greater Cd accumulation by maize plants than predicted by the Cd²⁺ activity. A better integration of the complete dataset for the 3 harvest times (6, 9 and 11 days after treatment) was achieved by including consideration of both the duration of Cd exposure and especially the root surface area to express Cd uptake. Similarly, the fit of the BLM was also improved when taking into account exposure time and expressing uptake in terms of root morphological parameters.     

污水处理厂出水中雌激素活性物质浓度与生态风险水平

再生水在环境和景观水体利用中,由微量有毒有害污染物,特别是内分泌干扰物引起的长期生态风险备受关注.以再生水生态风险控制为目的,对城市污水处理厂出水(再生水)中雌激素活性物质浓度分布情况进行了研究,归纳了8种雌激素活性物质的出水浓度水平,比较分析了各物质的雌激素活性和生态风险.结果表明:8种物质的质量浓度分布在ng/L～μg/L,其中ρ(类固醇)最低,为nd～50 ng/L;ρ(酚类)及ρ(酞酸酯类)主要在μg/L水平,个别高达40μg/L.雌激素活性分析和生态风险评价结果表明,污水处理厂出水(再生水)中3类雌激素活性物质的雌激素活性和生态风险顺序均为类固醇物质酚类物质酞酸酯类物质.城市污水再生处理厂应优先控制乙炔基雌二醇(EE2)、雌酮(E1)和雌三醇(E3)等3种雌激素活性物质.     

我国北方典型地区居民呼吸暴露参数研究

呼吸暴露参数是准确估算人体对污染物的暴露剂量和健康风险评估的重要参数之一,而我国目前对于该项工作的调查研究较少.采用问卷调查的方式对我国北方典型地区——太原的2860名受试者进行了时间-活动模式的研究,结合人体能量估算模型,计算出适合该地区居民的呼吸速率参数,并与国内外情况进行对比分析.结果表明:该地区居民室内日平均活动时间为16.1～18.4h;不同性别、不同年龄组的城市和农村居民从事各种强度活动的时间有很大差异;同时得出,该市城市居民长期暴露的呼吸速率参数为10.72～14.53m3/d,农村居民为15.61～22.59m3/d.与我国相关文献数据和美国环境保护署(USEPA)的数据相比,如果直接引用USEPA的数据,将会给健康风险带来30%～50%的偏差.