本文主要研究内容
作者丁翰林（2019）在《真菌黑曲霉（Aspergillus niger）对U（Ⅵ）的吸附富集与机理研究》一文中研究指出：黑曲霉(A.niger)作为工业高产酶系菌株,在发酵行业被广泛研究,由于其对外界胁迫具有较强耐受特性,能够在放射性核素及伴生重金属污染的生物修复过程中表现出一定优势。本研究选取模式菌株A.niger为研究对象,针对尾矿周边污染物中存在的放射性污染六价铀U(Ⅵ)为胁迫介质,通过对U(Ⅵ)胁迫培养下A.niger的生理生化指标受影响的程度的研究,全面分析在U(Ⅵ)胁迫过程中A.niger细胞损伤效应及其耐受程度和潜在的应对胁迫的细胞内部抗胁迫响应机制。此外,通过对活性及非活性A.niger菌球对U(Ⅵ)的吸附富集过程进行微观分析,进而详细的探索微生物与放射性核素结合的潜在吸附富集特性及微观吸附机理。在此研究结果的基础上,对A.niger生物质材料进行改性研究,进一步验证其潜在的放射性污染废水的生物净化和实际应用潜力。研究结果如下:(1)耐受真菌A.niger在实验设定的不同初始U(Ⅵ)浓度暴露胁迫下发现其在100-125 mg/L时,菌球的生长、袍子的萌发才开始出现较为明显的抑制,说明A.niger对核素U(Ⅵ)表现出一定的抗性。通过对初始U(Ⅵ)浓度、介质温度、pH及投料量进行吸附富集实验的研究结果表明,当环境介质温度维持在30℃、pH=5、0.04g投料量时能够维持A.niger的最佳吸附状态,达到39.38 mg/g。通过长期暴露在U(Ⅵ)胁迫环境中的实验结果表明,A.niger细胞逐渐通过生长代谢和协同细胞内部的潜在解毒抗性机制,能够降低表面富集和向内部转移的U(Ⅵ)所造成的毒性影响。在额外添加草酸的研究中发现,草酸可以络合重金属离子形成草酸盐络合物并降低金属离子的毒性,通过对比两种培养基培养三天内Aniger细胞内外富集情况的研究结果发现,额外添加草酸的总富集量和细胞外富集量较对照组相比呈现增加趋势,而转移至细胞内的U(Ⅵ)出现降低趋势,说明外源草酸可以促进A.niger对U(Ⅵ)的富集,同时又能降低环境介质中U(Ⅵ)的活度与转移性,达到降低U(Ⅵ)毒性胁迫的作用。通过对液体发酵胁迫培养情况下A.niger细胞内降解酶酶活的检测发现,长期暴露在存在U(Ⅵ)胁迫的发酵体系中的A.niger维素降解酶系受影响程度表现为:在实验设定的最高浓度(125 mg/L)下,羧甲基纤维素酶活(CMCA)较对照组下降18.86%,滤纸酶活(FPA)下降28.32%。而受应激反应造成A.niger细胞内木质素降解酶系的影响较为明显,LiP和MnP酶活较对照组相比分别下降25.57%和42.06%。由此也反映出细胞内部的损伤程度较为明显。(2)通过对A.niger长期暴露在U(Ⅵ)胁迫情况下细胞内氧化损伤效应及其内部抗氧化机制受影响程度进行研究分析。结果表明A.niger细胞长期暴露在U(Ⅵ)胁迫介质中,其细胞内部由于核素毒性的积累,产生应激反应造成氧自由基物质(O2·-、·HO、H2O2)的显著增加,最终通过细胞内较高浓度的MDA含量反应其质膜的氧化损伤程度。结合抗氧化系统中主要的SOD和CAT酶活活性的进一步研究发现,随着介质中U(Ⅵ)浓度的上升,两种抗氧化酶活性也随之显著增加,而在受胁迫的第三天后开始出现损伤程度的缓解,说明A.niger通过细胞代谢调节和抗氧化机制开始产生对U(Ⅵ)的抗性,这一结果也与其细胞内部GSH-Px的含量增加相吻合,GSH-Px开始逐渐缓解核素U(Ⅵ)对细胞产生的氧化损伤。暴露在U(Ⅵ)胁迫下A.niger细胞损伤主要原因是U(Ⅵ)的过量积累影响菌体生长代谢,诱导其产生氧自由基并引起毒性产生,通过对R(SOD/CAT)与细胞内H2O2含量的相关性分析发现,A.niger细胞内部的应激反应触发SOD酶活活性的增加,同时,自由基的清除过程造成过量的CAT酶消耗,破坏了生长初期的CAT酶活供给平衡,最终导致细胞内H2O2的积累,引起质膜的氧化损伤。(3)通过对活性及非活性A.niger菌球吸附剂对U(Ⅵ)的吸附富集实验进行对比研究。实验结果表明,非活性A.niger菌球吸附剂由于失去活性,不再受到影响吸附因素如温度、pH、高浓度U(Ⅵ)毒性影响,表现出较活性菌球的相比更高效的去除能力。在最佳的吸附环境下(30℃、pH=5),非活性菌球的吸附能力为83.40 mg/g,远高于活性菌球50.65 mg/g。通过对吸附模型的研究实验发现,两种菌球的U(Ⅵ)吸附过程能够很好的采用Langmuir等温模型和伪二阶动力学模型进行拟合分析,并且结合热力学模型能够将两种菌球对核素U(Ⅵ)的吸附特性总结为三个过程:溶液中游离的U(Ⅵ)首先与菌球表面大量的羟基、氨基、羧基等吸附位点进行单层覆盖点对点的快速吸附;通过消耗能量的生物传质过程将U(Ⅵ)扩散至紧密缠绕的菌丝球内部直至所有吸附位点被完全占据。此外,结合现代的分析手段(SEM、EDX、FT-IR、XPS)对核素U(Ⅵ)吸附机理进行深入研究分析。结果发现A.niger菌丝体表面富含大量的活性羟基、氨基、羧基官能团,能够与羟基化的核素发生络合,从而固定吸附介质中的目标污染物达到吸附富集的效果。
Abstract
hei qu mei (A.niger)zuo wei gong ye gao chan mei ji jun zhu ,zai fa jiao hang ye bei an fan yan jiu ,you yu ji dui wai jie xie pai ju you jiao jiang nai shou te xing ,neng gou zai fang she xing he su ji ban sheng chong jin shu wu ran de sheng wu xiu fu guo cheng zhong biao xian chu yi ding you shi 。ben yan jiu shua qu mo shi jun zhu A.nigerwei yan jiu dui xiang ,zhen dui wei kuang zhou bian wu ran wu zhong cun zai de fang she xing wu ran liu jia you U(Ⅵ)wei xie pai jie zhi ,tong guo dui U(Ⅵ)xie pai pei yang xia A.nigerde sheng li sheng hua zhi biao shou ying xiang de cheng du de yan jiu ,quan mian fen xi zai U(Ⅵ)xie pai guo cheng zhong A.nigerxi bao sun shang xiao ying ji ji nai shou cheng du he qian zai de ying dui xie pai de xi bao nei bu kang xie pai xiang ying ji zhi 。ci wai ,tong guo dui huo xing ji fei huo xing A.nigerjun qiu dui U(Ⅵ)de xi fu fu ji guo cheng jin hang wei guan fen xi ,jin er xiang xi de tan suo wei sheng wu yu fang she xing he su jie ge de qian zai xi fu fu ji te xing ji wei guan xi fu ji li 。zai ci yan jiu jie guo de ji chu shang ,dui A.nigersheng wu zhi cai liao jin hang gai xing yan jiu ,jin yi bu yan zheng ji qian zai de fang she xing wu ran fei shui de sheng wu jing hua he shi ji ying yong qian li 。yan jiu jie guo ru xia :(1)nai shou zhen jun A.nigerzai shi yan she ding de bu tong chu shi U(Ⅵ)nong du bao lou xie pai xia fa xian ji zai 100-125 mg/Lshi ,jun qiu de sheng chang 、pao zi de meng fa cai kai shi chu xian jiao wei ming xian de yi zhi ,shui ming A.nigerdui he su U(Ⅵ)biao xian chu yi ding de kang xing 。tong guo dui chu shi U(Ⅵ)nong du 、jie zhi wen du 、pHji tou liao liang jin hang xi fu fu ji shi yan de yan jiu jie guo biao ming ,dang huan jing jie zhi wen du wei chi zai 30℃、pH=5、0.04gtou liao liang shi neng gou wei chi A.nigerde zui jia xi fu zhuang tai ,da dao 39.38 mg/g。tong guo chang ji bao lou zai U(Ⅵ)xie pai huan jing zhong de shi yan jie guo biao ming ,A.nigerxi bao zhu jian tong guo sheng chang dai xie he xie tong xi bao nei bu de qian zai jie du kang xing ji zhi ,neng gou jiang di biao mian fu ji he xiang nei bu zhuai yi de U(Ⅵ)suo zao cheng de du xing ying xiang 。zai e wai tian jia cao suan de yan jiu zhong fa xian ,cao suan ke yi lao ge chong jin shu li zi xing cheng cao suan yan lao ge wu bing jiang di jin shu li zi de du xing ,tong guo dui bi liang chong pei yang ji pei yang san tian nei Anigerxi bao nei wai fu ji qing kuang de yan jiu jie guo fa xian ,e wai tian jia cao suan de zong fu ji liang he xi bao wai fu ji liang jiao dui zhao zu xiang bi cheng xian zeng jia qu shi ,er zhuai yi zhi xi bao nei de U(Ⅵ)chu xian jiang di qu shi ,shui ming wai yuan cao suan ke yi cu jin A.nigerdui U(Ⅵ)de fu ji ,tong shi you neng jiang di huan jing jie zhi zhong U(Ⅵ)de huo du yu zhuai yi xing ,da dao jiang di U(Ⅵ)du xing xie pai de zuo yong 。tong guo dui ye ti fa jiao xie pai pei yang qing kuang xia A.nigerxi bao nei jiang jie mei mei huo de jian ce fa xian ,chang ji bao lou zai cun zai U(Ⅵ)xie pai de fa jiao ti ji zhong de A.nigerwei su jiang jie mei ji shou ying xiang cheng du biao xian wei :zai shi yan she ding de zui gao nong du (125 mg/L)xia ,suo jia ji qian wei su mei huo (CMCA)jiao dui zhao zu xia jiang 18.86%,lv zhi mei huo (FPA)xia jiang 28.32%。er shou ying ji fan ying zao cheng A.nigerxi bao nei mu zhi su jiang jie mei ji de ying xiang jiao wei ming xian ,LiPhe MnPmei huo jiao dui zhao zu xiang bi fen bie xia jiang 25.57%he 42.06%。you ci ye fan ying chu xi bao nei bu de sun shang cheng du jiao wei ming xian 。(2)tong guo dui A.nigerchang ji bao lou zai U(Ⅵ)xie pai qing kuang xia xi bao nei yang hua sun shang xiao ying ji ji nei bu kang yang hua ji zhi shou ying xiang cheng du jin hang yan jiu fen xi 。jie guo biao ming A.nigerxi bao chang ji bao lou zai U(Ⅵ)xie pai jie zhi zhong ,ji xi bao nei bu you yu he su du xing de ji lei ,chan sheng ying ji fan ying zao cheng yang zi you ji wu zhi (O2·-、·HO、H2O2)de xian zhe zeng jia ,zui zhong tong guo xi bao nei jiao gao nong du de MDAhan liang fan ying ji zhi mo de yang hua sun shang cheng du 。jie ge kang yang hua ji tong zhong zhu yao de SODhe CATmei huo huo xing de jin yi bu yan jiu fa xian ,sui zhao jie zhi zhong U(Ⅵ)nong du de shang sheng ,liang chong kang yang hua mei huo xing ye sui zhi xian zhe zeng jia ,er zai shou xie pai de di san tian hou kai shi chu xian sun shang cheng du de huan jie ,shui ming A.nigertong guo xi bao dai xie diao jie he kang yang hua ji zhi kai shi chan sheng dui U(Ⅵ)de kang xing ,zhe yi jie guo ye yu ji xi bao nei bu GSH-Pxde han liang zeng jia xiang wen ge ,GSH-Pxkai shi zhu jian huan jie he su U(Ⅵ)dui xi bao chan sheng de yang hua sun shang 。bao lou zai U(Ⅵ)xie pai xia A.nigerxi bao sun shang zhu yao yuan yin shi U(Ⅵ)de guo liang ji lei ying xiang jun ti sheng chang dai xie ,you dao ji chan sheng yang zi you ji bing yin qi du xing chan sheng ,tong guo dui R(SOD/CAT)yu xi bao nei H2O2han liang de xiang guan xing fen xi fa xian ,A.nigerxi bao nei bu de ying ji fan ying chu fa SODmei huo huo xing de zeng jia ,tong shi ,zi you ji de qing chu guo cheng zao cheng guo liang de CATmei xiao hao ,po huai le sheng chang chu ji de CATmei huo gong gei ping heng ,zui zhong dao zhi xi bao nei H2O2de ji lei ,yin qi zhi mo de yang hua sun shang 。(3)tong guo dui huo xing ji fei huo xing A.nigerjun qiu xi fu ji dui U(Ⅵ)de xi fu fu ji shi yan jin hang dui bi yan jiu 。shi yan jie guo biao ming ,fei huo xing A.nigerjun qiu xi fu ji you yu shi qu huo xing ,bu zai shou dao ying xiang xi fu yin su ru wen du 、pH、gao nong du U(Ⅵ)du xing ying xiang ,biao xian chu jiao huo xing jun qiu de xiang bi geng gao xiao de qu chu neng li 。zai zui jia de xi fu huan jing xia (30℃、pH=5),fei huo xing jun qiu de xi fu neng li wei 83.40 mg/g,yuan gao yu huo xing jun qiu 50.65 mg/g。tong guo dui xi fu mo xing de yan jiu shi yan fa xian ,liang chong jun qiu de U(Ⅵ)xi fu guo cheng neng gou hen hao de cai yong Langmuirdeng wen mo xing he wei er jie dong li xue mo xing jin hang ni ge fen xi ,bing ju jie ge re li xue mo xing neng gou jiang liang chong jun qiu dui he su U(Ⅵ)de xi fu te xing zong jie wei san ge guo cheng :rong ye zhong you li de U(Ⅵ)shou xian yu jun qiu biao mian da liang de qiang ji 、an ji 、suo ji deng xi fu wei dian jin hang chan ceng fu gai dian dui dian de kuai su xi fu ;tong guo xiao hao neng liang de sheng wu chuan zhi guo cheng jiang U(Ⅵ)kuo san zhi jin mi chan rao de jun si qiu nei bu zhi zhi suo you xi fu wei dian bei wan quan zhan ju 。ci wai ,jie ge xian dai de fen xi shou duan (SEM、EDX、FT-IR、XPS)dui he su U(Ⅵ)xi fu ji li jin hang shen ru yan jiu fen xi 。jie guo fa xian A.nigerjun si ti biao mian fu han da liang de huo xing qiang ji 、an ji 、suo ji guan neng tuan ,neng gou yu qiang ji hua de he su fa sheng lao ge ,cong er gu ding xi fu jie zhi zhong de mu biao wu ran wu da dao xi fu fu ji de xiao guo 。
论文参考文献
论文详细介绍
论文作者分别是来自西南科技大学的丁翰林，发表于刊物西南科技大学2019-09-02论文，是一篇关于黑曲霉论文,氧化应激论文,生物积累论文,抗氧化酶论文,抗氧化反应论文,解毒机制论文,木质素分解酶论文,吸附机理论文,西南科技大学2019-09-02论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自西南科技大学2019-09-02论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。
标签：黑曲霉论文; 氧化应激论文; 生物积累论文; 抗氧化酶论文; 抗氧化反应论文; 解毒机制论文; 木质素分解酶论文; 吸附机理论文; 西南科技大学2019-09-02论文;