通过控制直流电场强度对氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f.)进行电场刺激实验,探究直流电场电动力学效应对T.f.生物活性的影响以及繁殖代谢情况。考察分析了不同弱电流强度(100 m A)下,T.f.的菌密度、菌液p H变化、菌液总...通过控制直流电场强度对氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f.)进行电场刺激实验,探究直流电场电动力学效应对T.f.生物活性的影响以及繁殖代谢情况。考察分析了不同弱电流强度(100 m A)下,T.f.的菌密度、菌液p H变化、菌液总蛋白量以及细菌形态的变化。实验结果表明,与未施加电场的对照组对比,在20 m A电流强度作用下,明显有增加T.f.的菌密度的作用,过高的电流抑制了细菌的生长。通过实验发现当施加20 m A电流时,氧化亚铁硫杆菌胞内蛋白总量达到未施加电场的2.15倍,能够明显提高T.f.细胞膜的通透性,增加细胞膜的厚度。这对于大规模化利用T.f.浸出废弃线路板中金属提供了科学依据和参考。展开更多
A study was undertaken to investigate the production of amino acids from excess activated sludge (EAS) by enzymatic hydrolysis. Firstly, the protein was extracted from EAS. Secondly, the protein solution was further h...A study was undertaken to investigate the production of amino acids from excess activated sludge (EAS) by enzymatic hydrolysis. Firstly, the protein was extracted from EAS. Secondly, the protein solution was further hydrolyzed under free enzyme or immobilized enzyme. The reversed phase high performance liquid chromatography (RP-HPLC) and inductively coupled plasma emission spectrometer (ICP) were applied to determine the contents of amino acids and heavy metals, respectively. The effects of enzyme/substrate(E/S), pH, temperature, and reaction time were investigated in detail. The results indicated that, the optimum conditions for protein hydrolysis were temperature 55℃, pH 10, E/S 9 g/L, and reaction time 8 h, and the highest yield of amino acids was more than 10 g/100 g dry sludge (DS) under free enzyme. Moreover, the security and nutrition were taken into consideration. There were seven kinds of essential amino acids and ten non-essential amino acids in the raw amino acid (RAA) solution, and the contents of heavy metals were lower, living up to Hygienical standard for feeds (China). This technology widens the source of amino acids and makes the extraction of amino acids from EAS more economic and effective.展开更多
文摘通过控制直流电场强度对氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f.)进行电场刺激实验,探究直流电场电动力学效应对T.f.生物活性的影响以及繁殖代谢情况。考察分析了不同弱电流强度(100 m A)下,T.f.的菌密度、菌液p H变化、菌液总蛋白量以及细菌形态的变化。实验结果表明,与未施加电场的对照组对比,在20 m A电流强度作用下,明显有增加T.f.的菌密度的作用,过高的电流抑制了细菌的生长。通过实验发现当施加20 m A电流时,氧化亚铁硫杆菌胞内蛋白总量达到未施加电场的2.15倍,能够明显提高T.f.细胞膜的通透性,增加细胞膜的厚度。这对于大规模化利用T.f.浸出废弃线路板中金属提供了科学依据和参考。
基金Innovation Program of Shanghai Municipal Education Commission,China(No.12zz069)Shanghai Municipal Natural Science Foundation,China(No.11ZR1400400)Fundamental Research Funds for the Central Universities,China(No.12D11303)
文摘A study was undertaken to investigate the production of amino acids from excess activated sludge (EAS) by enzymatic hydrolysis. Firstly, the protein was extracted from EAS. Secondly, the protein solution was further hydrolyzed under free enzyme or immobilized enzyme. The reversed phase high performance liquid chromatography (RP-HPLC) and inductively coupled plasma emission spectrometer (ICP) were applied to determine the contents of amino acids and heavy metals, respectively. The effects of enzyme/substrate(E/S), pH, temperature, and reaction time were investigated in detail. The results indicated that, the optimum conditions for protein hydrolysis were temperature 55℃, pH 10, E/S 9 g/L, and reaction time 8 h, and the highest yield of amino acids was more than 10 g/100 g dry sludge (DS) under free enzyme. Moreover, the security and nutrition were taken into consideration. There were seven kinds of essential amino acids and ten non-essential amino acids in the raw amino acid (RAA) solution, and the contents of heavy metals were lower, living up to Hygienical standard for feeds (China). This technology widens the source of amino acids and makes the extraction of amino acids from EAS more economic and effective.