土壤中酚类化合物降解菌筛选及应用

以苏州某化工场地污染土壤为菌源,以目标污染物为唯一碳源,通过连续培养、分离纯化筛选出高效酚类化合物降解菌。利用16S rDNA基因测序、构建基因树等分子生物学技术手段确定菌株种属,并研究了菌株对酚类化合物耐受性和降解效果。结果表明:以4-甲基苯酚(4-MP)和4-氯-3-甲基苯酚(4-C-3-MP)为唯一碳源筛选出了2株菌,分别为嗜麦芽窄食单胞菌(NM)和香茅醇假单胞菌(NCM)。菌株NM对4-MP耐受性良好,4-MP浓度为400 mg/L时仍能生长繁殖;菌株NCM对4-C-3-MP耐受性较差,4-C-3-MP浓度≥200 mg/L时,菌株NCM受到完全抑制,停止生长。菌株NM不能降解土壤中苯酚,对4-MP和4-C-3-MP去除效果良好,第20天时去除率分别达到43%和22%;菌株NCM对土壤中苯酚、4-MP和4-C-3-MP均有降解效果,第20天时苯酚、4-MP和4-C-3-MP去除率分别为20%、26%和28%,较第15天时去除率分别提高了18、3和6个百分点。     

Effects of various reaction parameters on solvolytical depolymerization of lignin in sub- and supercritical ethanol

Organosolv lignin was treated with ethanol at sub/supercritical temperatures (200, 275, and 350 °C) for conversion to low molecular phenols under different reaction times (20, 40, and 60 min), solvent-to-lignin ratios (50, 100, and 150 mL g⁻¹), and initial hydrogen gas pressures (2 and 3 MPa). Essential lignin-degraded products, oil (liquid), char (solid), and gas were obtained, and their yields were directly influenced by reaction conditions. In particular, concurrent reactions involving depolymerization and recondensation as well as further (secondary) decomposition were significantly accelerated with increasing temperature, leading to both lignin-derived phenols in the oil fraction and undesirable products (char and gas).     

酚类化合物抑制斜生栅藻生长的毒性效应

本文运用评价化学品对藻类毒性的标准实验方法,得出苯酚,邻氯苯酚、２,４－二氯苯酚和五氯酚抑制斜生栅藻生长的９６ｈ－ＥＣ５０分别为３４１．８５,２５和１．５ｍｇ·１＾－１,实验结果表明,在３００,３５０和４００ｍｇ·ｌ＾－１三种本酚初始浓度下,斜生栅藻都不具备降解苯酚的能力,即使在培养基中基本没有无机碳源的情况下,斜生栅藻仍不具备降解苯酚的能力。     

Impact of soil management practices on yield,fruit quality,and antioxidant contents of pepper at four stages of fruit development

Peppers, a significant component of the human diet in many regions of the world, provide vitamins A (β-carotene) and C, and are also a source of many other antioxidants such as capsaicin, dihydrocapsaicin, and phenols. Enhancing the concentration of antioxidants in plants grown in soil amended with recycled waste has not been completely investigated. Changes in pepper antioxidant content in relation to soil amendments and fruit development were investigated. The main objectives of this investigation were to: (i) quantify concentrations of capsaicin, dihydrocapsaicin, β-carotene, ascorbic acid, phenols, and soluble sugars in the fruits of Capsicum annuum L. (cv. Xcatic) grown under four soil management practices: yard waste (YW), sewage sludge (SS), chicken manure (CM), and no-much (NM) bare soil and (ii) monitor antioxidant concentrations in fruits of plants grown under these practices and during fruit ripening from green into red mature fruits. Total marketable pepper yield was increased by 34% and 15% in SS and CM treatments, respectively, compared to NM bare soil; whereas, the number of culls (fruits that fail to meet the requirements of foregoing grades) was lower in YW compared to SS and CM treatments. Regardless of fruit color, pepper fruits from YW amended soil contained the greatest concentrations of capsaicin and dihydrocapsaicin. When different colored pepper fruits (green, yellow, orange, and red) were analyzed, orange and red contained the greatest β-carotene and sugar contents; whereas, green fruits contained the greatest concentrations of total phenols and ascorbic acid.     

影响挥发酚测定因素的探讨

本文对普遍采用的4-氨基安替比林萃取分光光度法测定饮用水中挥发酚的多种影响因素进行了探讨,获得的结果对饮用水中挥发酚的准确测定有较好的实用性。     

酚类化合物的QSAR研究

直接应用化合物的分子结构式产生的结构描述参量研究了45个酚类化合物的麻醉毒性和分子结构之间的相关性,用多元回归分析和神经网络法建立了相应的数学模型,并用其预测了5个酚类化合物的麻醉毒性.结果表明,所提取的结构参量较好地反映这类化合物的结构特性,而用神经网络法所得结果优于多元回归分析结果.     

15种取代酚对淡水发光菌Q67的毒性及定量构效分析

为了更加准确和便捷地预测各种取代酚类化合物的急性毒性,以淡水发光菌Q67(Vibrio qinghaiensis sp.-Q67)为受试生物,测定了15种典型取代酚的急性毒性;采用logD(正辛醇/水分配系数),LUMO(分子最低空轨道能)和MW(分子量)等取代酚的7种主要结构参数,利用偏最小二乘回归法建立了定量结构-活性相关(quantitative structure-activity relationships,QSAR)模型.结果表明,15种取代酚的EC50在5.76×10-6 ～ 1.27×10-3 mol·L-1之间,且有很好的剂量-效应关系;QSAR模型的主成分分析显示,-log     

酚类化合物短期暴露对小麦和大麦苗期根伸长的影响

采用小麦和大麦为受试作物,以其在受试化合物污染的土壤中培育3 d后获得的根伸长的半数抑制浓度(IC50)评价了12种酚类化合物的毒性效应。结果表明,在所设浓度范围内,酚类对作物根伸长均存在剂量-效应关系。小麦对受试酚类的IC50范围为:12.92~231.76 mg·kg-1,其中邻苯二酚只在最高浓度500 mg·kg-1时对小麦的毒性效应显著。大麦对受试化合物的IC50范围为:7.15~478.31 mg·kg-1。小麦对3-甲基酚、双酚A、2-萘酚和壬基酚相对敏感,而其它8种化合物则是大麦相对更敏感。酚类化合物对小麦和大麦的毒性强度整体趋势一致。     

苯酚类化合物光解量子产率与结构性质的定量关系

采用量子化学PM3算法计算得到的苯酚类化合物的量子化学参数,应用偏最小二乘(PLS)算法,建立了能预测苯酚类化合物光解量子产率(Y)的定量结构-性质关系(QSPR)模型.影响苯酚类化合物光解量子产率的主要因素是分子最高占据轨道能(Ehomo)和分子生成热(HOF),logY值随着Ehomo的增大而增大,随着HOF的增大而减小.分子的电负性和(Ehomo-Ehomo)2对logY值也有一定的影响,电负性和(Ehomo-Ehomo)²较小的分子,其logY值也较大.     

Formation of chloroarenes upon gas-phase pyrolysis and slow combustion of benzene-HCl mixtures

Pyrolysis (800–900°C, ca. 5 s) of benzene/HC1 mixtures leads to chlorobenzene (1) even in a reducing environment of H₂ and/or CH₄. With added oxygen, 1 is formed even at 550°C; such slow combustions also yield chlorinated phenols and dibenzofurans.