title: Low-strength ultrasonication positively affects methanogenic granules toward higher AD performance: Hydrolytic enzyme excretions.
abstract: In our previous studies, enhanced methane (CH4) production using low-strength ultrasonication was achieved and the results were evidenced by physico-chemical and molecular biological approaches. As a final continuation study, the effects of low-strength ultrasonication on the activities of hydrolytic enzymes (amylase, cellulase, and protease) were investigated on methanogenic granules given that hydrolysis regulates the whole anaerobic digestion (AD) process. Up to 213% enhanced hydrolytic enzyme activities were observed, and they seem to be highly related to the enhanced CH4production. However, the effects of ultrasonication on the distribution (liquid- and solid-phases) of hydrolytic enzymes were negligible. Enzymatic activation by low-strength ultrasonication was hypothetically caused by acoustic streaming, presumably enabling to overcome the masking effect, substrate inhibition and spatial constraint.
authors.affiliation: Department of Biological and Environmental Science, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang, Gyeonggi-do, Republic of Korea.
authors.forename: Si-Kyung
authors.initials: SK
authors.lastname: Cho
authors.affiliation: College of Agriculture, Forestry and Natural Resource Management, University of Hawaii at Hilo, Hilo, HI, USA.
authors.forename: Yeo-Myeong
authors.initials: YM
authors.lastname: Yun
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-ro, Pohang, Gyeongbuk, Republic of Korea. Electronic address: candlit@postech.ac.kr.
authors.forename: Seung Gu
authors.initials: SG
authors.lastname: Shin
mesh_terms: D006867:Hydrolases / Q000378:metabolism*; D006868:Hydrolysis; D008697:Methane / Q000096:biosynthesis*; D012722:Sewage / Q000382:microbiology*; D013010:Sonication
chemical_list: D012722:Sewage; D006867:Hydrolases; D008697:Methane
keywords: Hydrolytic enzyme; Low-strength ultrasonication; Methanogenic granule; Upflow anaerobic sludge blanket