Zhan Yu, Shi Wan-Sheng, Zhao Ming-Xing, Xu Zhi-Yang, Ruan Wen-Quan, Song Lian, Zhu Ge
School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China.
Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China.
Huan Jing Ke Xue. 2018 Jun 8;39(6):2778-2785. doi: 10.13227/j.hjkx.201709250.
Dewatered waste sludge with a total solid (TS) concentration of 12% was used for mesophilic (37℃) anaerobic digestion (AD). The biotransformation mechanism of protein and the reason for the low conversion efficiency of protein under high solids AD was investigated by analyzing the variation of protein composition in the sludge before and after AD. The results showed that the conversion rate of protein in the sludge was 34.26% after 45 days of AD. The reason for the low efficiency of protein conversion was the poor mass transfer efficiency under the condition of high solids content and the large amount of ammonia nitrogen produced with the hydrolysis. After 45 days of AD, the total ammonia nitrogen (TAN) concentration reached 1201 mg·L, which resulted in the inhibition of the AD process, especially the decomposition of protein. Some of the protein converted to humic acid-like and fulvic acid-like substances, which are more difficult to decompose based on the three-dimensional fluorescence spectroscopy (3D-EEM) analysis. Two-dimensional electrophoresis (2-DE)- mass spectrometry (MS) was adopted for identifying the composition of protein in sludge before and after AD. It showed that the relative molecular weight and the isoelectric point (pI) of the protein in the sludge decreased after AD and most of the proteins left in the digested sludge came from the micro-organisms. These proteins cannot be further decomposed by the microbes because of the decreased microbial metabolic capacity at the end of the AD process or lack of specific enzymes for the hydrolysis of these proteins. This ultimately resulted in the low decomposition efficiency of the total protein in the sludge.
使用总固体（TS）浓度为12%的脱水废弃污泥进行中温（37℃）厌氧消化（AD）。通过分析污泥厌氧消化前后蛋白质组成的变化，研究了蛋白质的生物转化机制以及高固体厌氧消化条件下蛋白质转化效率低的原因。结果表明，厌氧消化45天后，污泥中蛋白质的转化率为34.26%。蛋白质转化效率低的原因是高固体含量条件下传质效率差以及水解过程中产生大量氨氮。厌氧消化45天后，总氨氮（TAN）浓度达到1201mg·L，这导致厌氧消化过程受到抑制，尤其是蛋白质的分解。基于三维荧光光谱（3D-EEM）分析，部分蛋白质转化为类腐殖酸和类富里酸物质，这些物质更难分解。采用二维电泳（2-DE）-质谱（MS）鉴定厌氧消化前后污泥中蛋白质的组成。结果表明，厌氧消化后污泥中蛋白质的相对分子量和等电点（pI）降低，消化污泥中残留的大部分蛋白质来自微生物。由于厌氧消化过程末期微生物代谢能力下降或缺乏水解这些蛋白质的特定酶，这些蛋白质无法被微生物进一步分解。这最终导致污泥中总蛋白质的分解效率较低。
