title: Effects of ultrasonic-assisted thermophilic bacteria pretreatment on hydrolysis, acidification, and microbial communities in waste-activated sludge fermentation process.
abstract: A novel pretreatment method combining ultrasonic with thermophilic bacteria (Geobacillus sp. G1) was employed to pretreat waste-activated sludge (WAS) for enhancing the WAS hydrolysis and subsequent volatile fatty acids (VFAs) production. The soluble protein and carbohydrate were mostly released from intracellular ultrasonic-assisted Geobacillus sp. G1 pretreatment, and accumulated to 917 ± 70 and 772 ± 89 mg COD/L, respectively, which were 2.53- and 2.62-fold higher than that obtained in control test. Excitation emission matrix (EEM) fluorescence spectroscopy revealed the highest fluorescence intensity (FI) of protein-like substances, indicating the synergistic effect of ultrasonic and Geobacillus sp. G1 pretreatments on WAS hydrolysis. The maximum VFAs accumulation was 4437 ± 15 mg COD/L obtained in ultrasonic-assisted Geobacillus sp. G1 pretreatment test. High-throughput pyrosequencing analysis investigated that the microbial communities were substantial determined by the pretreatment used. The hydrolysis enhancement was caused by an increase in extracellular enzymes, which was produced by one of dominant species Caloramator sp. The positive effect was well explained to the enhancement of WAS hydrolysis and final VFAs accumulation.
authors: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), P.O. Box 2614, 202 Haihe Road, Harbin, 150090, China.
authors: Chunxue
authors: C
authors: Yang
authors: Aijuan
authors: A
authors: Zhou
authors: Zhangwei
authors: Z
authors: He
authors: Lei
authors: L
authors: Jiang
authors: Zechong
authors: Z
authors: Guo
authors: Aijie
authors: A
authors: Wang
authors: Wenzong
authors: W
authors: Liu
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D056506:Geobacillus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D059014:High-Throughput Nucleotide Sequencing; D006812:Humic Substances / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D016133:Polymerase Chain Reaction; D011108:Polymers / Q000032:analysis*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D013010:Sonication; D013050:Spectrometry, Fluorescence
chemical_list: D005232:Fatty Acids, Volatile; D006812:Humic Substances; D011108:Polymers; D012336:RNA, Ribosomal, 16S; D012722:Sewage