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Frontiers of Environmental Science & Engineering

ISSN 2095-2201

ISSN 2095-221X(Online)

CN 10-1013/X

Postal Subscription Code 80-973

2018 Impact Factor: 3.883

Front. Environ. Sci. Eng.    2019, Vol. 13 Issue (2) : 25    https://doi.org/10.1007/s11783-019-1114-7
RESEARCH ARTICLE
Fate of proteins of waste activated sludge during thermal alkali pretreatment in terms of sludge protein recovery
Xiaoli Song1,2, Zhenghua Shi1,2, Xiufen Li1,2,3(), Xinhua Wang1,2, Yueping Ren1,2
1. Laboratory of Environmental Biotechnology, School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
2. Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi 214122, China
3. Jiangsu Cooperative Innovation Center of Technology and Material of Water Treatment, Suzhou 215009, China
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Abstract

Maillard reaction between reducing sugars and amides happened during pretreatment.

Over 90 min of TAH at the optimal condition, 67.59% sludge proteins was solubilized.

15.84% soluble proteins broke down to materials with small molecular weight.

Proteins are the major organic component s of waste activated sludge (WAS); the recovery of sludge proteins is economically valuable. To efficiently recover sludge proteins, WAS should undergo hydrolysis pretreatment to fully release proteins from sludge flocs and microbial cells into aqueous phase. One of the most widely used chemical methods for that is thermal alkali hydrolysis (TAH). Here, the soluble protein concentration achieved the highest level over 90 min of TAH pretreatment at 80°C; the sludge floc disintegration and microbial cell destruction were maximized according to the content profiles of bound extracellular polymeric substance (EPS) and ribonucleic acid (RNA) of sludge. Both less proteins broken down to materials with small molecular weight and less melanoidin generated were responsible. TAH pretreatment at 80°C for 90 min resulted in the solubilization of 67.59% of sludge proteins. 34.64% of solubilized proteins was present in soluble high molecular; 1.55% and 4.85% broke down to polypeptides and amino acids. The lost proteins via being converted to ammonium and nitrate nitrogen accounted for 9.44% of solubilized proteins. It was important to understand the fate of sludge proteins during TAH pretreatment in terms of protein recovery, which would be helpful for designing the downstream protein separation method and its potential application.

Keywords Sludge flocs      Microbial cells      Hydrolysate      Protein breakdown      Melanoidin     
Corresponding Author(s): Xiufen Li   
Issue Date: 26 March 2019
 Cite this article:   
Xiaoli Song,Zhenghua Shi,Xiufen Li, et al. Fate of proteins of waste activated sludge during thermal alkali pretreatment in terms of sludge protein recovery[J]. Front. Environ. Sci. Eng., 2019, 13(2): 25.
 URL:  
https://academic.hep.com.cn/fese/EN/10.1007/s11783-019-1114-7
https://academic.hep.com.cn/fese/EN/Y2019/V13/I2/25
Water content (%) Soluble Proteins (mg/L) Crude proteins (%) TS (g/L) VS (g/L) pH
84.22±0.25 3.59±0.72 28.00±3.28 30.00±1.21 19.00±0.63 6.9±0.5
Tab.1  Characteristics of raw WAS.
Fig.1  Profiles of soluble proteins during TAH pretreatment of WAS under 80°C and pH of 12.0.
Reaction time (min) Bound proteins Bound polysacchrides RNA
0 539.3±23.4 339.2±22.3 102±1
5 515.6±12.6 310.9±20.6 98±1
10 498.5±22.1 288.5±19.8 92±2
30 438.8±16.7 265.1±16.9 77±1
60 402.4±9.8 218.7±14.4 36±1
90 392.4±5.6 201.2±12.2 22±1
120 381.5±4.5 194.2±20.3 11±1
150 363.6±6.3 166.1±10.2 6±1
180 332.4±5.4 157.9±13.1 0
240 283.8±1.8 147.3±10.8 0
Tab.2  Profiles of soluble proteins during TAH pretreatment of WAS at 80°C (mg/L)
Items Temperature (°C)
55 80 100
Soluble proteins (mg/L) 1939±125 3216±90 3586±151
Solubilization rate of proteins (%) 34.50±1.62 51.67±1.18 64.07±1.88
Ammonium nitrogen (mg/L) 6.66±0.11 12.94±0.26 15.35±0.62
VAF(mg/L)
Acetic acid 396±43 434±5 552±29
Ethanol 116±9 128±1 150±4
Isobutyric acid 113±25 123±1 145±8
Total VFA 625±77 685±7 847±41
Total nitrogen (mg/L) 420.31±28.22 561.37±31.56 608.76±24.34
Tab.3  Soluble proteins and their derivatives as a function of reaction temperature during TAH pretreatment of WAS
Fig.2  Effect of reaction temperature on the size fractionation of soluble proteins during thermal alkali hydrolysis of BSA standard under pH of 12.0.
Fig.3  Effect of reaction temperature on key chemical characteristics during TAH pretreatment of BSA standard under pH of 12.0 [(a) Soluble proteins, (b) Polypeptides, (c) Amino acids, (d) Ammonium nitrogen, (e) Nitrate nitrogen and (f) VFAs].
Fig.4  Effect of reaction temperature on key chemical characteristics during TAH pretreatment of BSA and cellulose standards under pH of 12.0[(a) Soluble proteins, (b) Polypeptides, (c) Amino acids, (d) Ammonium nitrogen, (e) Nitrate nitrogen and (f) VFAs].
Item Cellulose (blank) BSA+ Cellulose (blank) Cellulose
(55°C)
BSA+ Cellulose (55°C)
Mono-saccharides 4.75±0.38 16.65±0.52 92.00±4.45 61.11±1.82
Disaccharides 58.00±1.46 not detected not detected not detected
Item Cellulose
(80°C)
BSA+ Cellulose (80°C) Cellulose
(100°C)
BSA+ Cellulose (100°C)
Mono-saccharides 161.00±6.48 62.00±2.24 393.00±9.50 253.00±9.64
Disaccharides not detected not detected not detected not detected
Tab.4  Mono- and disaccharides produced during TAH pretreatment of BSA and cellulose standards under different temperature (mg/L)
Fig.5  Effect of reaction temperature on UV254 of 50 × diluted hydrolysate during TAH pretreatment of BSA and cellulose standards under pH of 12.0.
Items Raw WAS WAS hydrolysate
Soluble proteins (mg/L) 8±1 3345±135
VFA (mg/L)
Acetic acid / 410±6
Isobutyric acid / 88±6
Ethanol / 133±6
Total VFA / 631±18
Polypeptides (mg/L) / 150.0±1.5
Amino acids (mg/L) / 468.75±10.90
Ammonium nitrogen (mg/L) 6.11±0.56 13.91±0.14
Nitrate nitrogen (mg/L) 0.77±0.09 132.00±1.41
Total nitrogen (mg/L) 6.62±0.44 678.14±14.84
Tab.5  Soluble proteins and their derivatives after during 90 min of TAH pretreatment at 80°C
Fig.6  Fate of sludge proteins during TAH pretreatment of WAS at 80°C under pH of 12.0 [(a) Pathway for proteins release and transformation; (b) percentages of various products].
1 S JAi, H Y Liu, M J Wu, G G Zeng, C P Yang (2018). Roles of acid-producing bacteria in anaerobic digestion of waste activated sludge. Frontiers of Environmental Science & Engineering, 12(6): 3
2 APHA (2005). Standard Methods for the Examination of Water and Wastewater (21st edition). Washington, D.C.: American Public Health Association, USA
3 BBohle, B Zwōlfer, AHeratizadeh (2006). Cooking birch pollenrelated food: Divergent consequences for Ig E- and T cellmediated reactivity in vitro and in vivo. Journal of Allergy and Clinical Immunology, 118(1): 242–249
4 Y GChen, S Jiang, H YYuan, QZhou, G W Gu (2007). Hydrolysis and acidification of waste activated sludge at different pHs. Water Research, 41: 683–689
5 S SChishti, S N Hasnain, M A Khan (1992). Studies on the recovery of sludge protein. Water Research, 26(2): 241–248
6 SCho, H Shin, DKim (2012). Waste activated sludge hydrolysis during ultrasonication: Two-step disintegration. Bioresource Technology, 121: 480–483
7 Y QDuan, A J Zhou, K L Wen, Z H Liu, W Z Liu, A J Wang, X P Yue (2019). Upgrading VFAs bioproduction from waste activated sludge via co-fermentation with soy sauce residue. Frontiers of Environmental Science & Engineering, 13(1): 3
8 MDubois, K A Gilles, J K Hamilton, P A Rebers, F Smith (1951). A colorimetric method for the determination of sugars. Nature, 28(7): 167–168
9 JDwyer, D Starrenburg, STait, KBarr, D J Batstone, P Lant (2008). Decreasing activated sludge thermal hydrolysis temperature reduces product colour, without decreasing degradability. Water Research, 42(18): 4699–4709
10 L BEwa, L Stanislaw (2001). RNA assay as a method of viable biomass determination in the organic fraction of municipal solid waste suspension. Biotechnology Letters, 23: 1057–1060
11 XGao, N Liu (2011). Determination of amino acid contents in the whole plant of Rumex dentatus by reversed-phase high-performance liquid chromatography with AccQ·Tag pre-column derivatization method. Food Science, 32(20): 160–163 (in Chinese)
12 HHamid, C Eskicioglu (2013). Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake. Water Research, 47: 4966–4977
13 XHuang, Z Yu, C (Li 2005).Advanced Biochemistry. Beijing: Chemical Industry Press
14 JHwang, L Zhang, SSeo, Y WLee, DJahng (2008). Protein recovery from excess sludge for its use as animal feed. Bioresource Technology, 99: 8949–8954
15 Y YLi, T Noike (1992). Upgrading of anaerobic-digestion of waste activated-sludge by thermal pretreatment. Water Science and Technology, 26(3–4): 857–866
16 YLiu, S Kong, YLi, HZeng (2009). Novel technology for sewage sludge utilization: Preparation of amino acids chelated trace elements (AACTE) fertilizer. Journal of Hazardous Materials, 171(1–3): 1159–1167
17 W TShier, S K Purwono (1994). Extraction of single-cell protein from activated sewage sludge: thermal solubilisation of protein. Bioresource Technology, 49: 157–162
18 STanaka, T Kobayashi, KKamiyama, M L N SBildan (1997). Effects of thermochemical pretreatment on the anaerobic digestion of waste activated sludge. Water Science and Technology, 35(8): 209–215
19 XWang, Y Li, JLiu, NRen, J Qu (2016). Augmentation of protein-derived acetic acid production by heat- alkaline-induced changes in protein structure and conformation. Water Research, 88: 595–603
20 C AWilson, J T Novak (2009). Hydrolysis of macromolecular components of primary and secondary wastewater sludge by thermal hydrolytic pretreatment. Water Research, 43: 4489–4498
21 KXiao, Y Chen, XJiang, W YSeow, CHe, Y Yin, YZhou (2017). Comparison of different treatment methods for protein solubilisation from waste activated sludge. Water Research, 122: 492–502
22 JZagon, B Jansen, MKnoppik (2010). Gene transcription analysis of carrot allergens by relative quantification with single and duplex reverse transcription real-time PCR. Analytical and Bioanalytical Chemistry, 396(1): 483–493
23 PZhang, G Zhang, WWang (2007). Ultrasonic treatment of biological sludge: Floc disintegration, cell lysis and inactivation. Bioresource Technology, 98: 207–210
24 JZhao, D Wang, XLi, QYang, H Chen, YZhong, GZeng (2015). Free nitrous acid serving as a pretreatment method for alkaline fermentation to enhance short-chain fatty acid production from waste activated sludge. Water Research, 78: 111–120
[1] Lei WANG, Yongtao LV, Xudong WANG, Yongzhe YANG, Xiaorong BAI. Micro-analysis of nitrogen transport and conversion inside activated sludge flocs using microelectrodes[J]. Front Envir Sci Eng Chin, 2011, 5(4): 633-638.
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