title: How Does Poly(hydroxyalkanoate) Affect Methane Production from the Anaerobic Digestion of Waste-Activated Sludge?
abstract: Recent studies demonstrate that, besides being used for production of biodegradable plastics, poly(hydroxyalkanoate) (PHA) that is accumulated in heterotrophic microorganisms during wastewater treatment has another novel application direction, i.e., being utilized for enhancing methane yield during the anaerobic digestion of waste-activated sludge (WAS). To date, however, the underlying mechanism of how PHA affects methane production remains largely unknown, and this limits optimization and application of the strategy. This study therefore aims to fill this knowledge gap. Experimental results showed that with the increase of sludge PHA levels from 21 to 184 mg/g of volatile suspended solids (VSS) the methane yield linearly increased from 168.0 to 246.1 mL/g of VSS (R(2) = 0.9834). Compared with protein and carbohydrate (the main components of a cell), PHA exhibited a higher biochemical methane potential on a unit VSS basis. It was also found that the increased PHA not only enhanced cell disruption of PHA cells but also benefited the soluble protein conversion of both PHA- and non-PHA cells. Moreover, the reactor fed with higher PHA sludge showed greater sludge hydrolysis and acidification than those fed with the lower PHA sludges. Further investigations using fluorescence in situ hybridization and enzyme analysis revealed that the increased PHA enhanced the abundance of methanogenic Archaea and increased the activities of protease, acetate kinase, and coenzyme F420, which were consistent with the observed methane yield. This work provides insights into PHA-involved WAS digestion systems and may have important implications for future operation of wastewater treatment plants.
authors.affiliation: College of Environmental Science and Engineering, Hunan University , Changsha 410082, China.|Key Laboratory of Environmental Biology and Pollution Control , Hunan University, Ministry of Education, Changsha 410082, China.|State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
authors.forename: Dongbo
authors.initials: D
authors.lastname: Wang
authors.affiliation: College of Environmental Science and Engineering, Hunan University , Changsha 410082, China.|Key Laboratory of Environmental Biology and Pollution Control , Hunan University, Ministry of Education, Changsha 410082, China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Zhao
authors.affiliation: College of Environmental Science and Engineering, Hunan University , Changsha 410082, China.|Key Laboratory of Environmental Biology and Pollution Control , Hunan University, Ministry of Education, Changsha 410082, China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University , 1239 Siping Road, Shanghai 200092, China.
authors.forename: Yinguang
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Advanced Water Management Centre, The University of Queensland , St. Lucia, Brisbane, Queensland 4072, Australia.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Bond
authors.affiliation: College of Environmental Science and Engineering, Hunan University , Changsha 410082, China.|Key Laboratory of Environmental Biology and Pollution Control , Hunan University, Ministry of Education, Changsha 410082, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
mesh_terms: D000693:Anaerobiosis / Q000187:drug effects; D001105:Archaea / Q000187:drug effects / Q000201:enzymology; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology; D006868:Hydrolysis; D017404:In Situ Hybridization, Fluorescence; D008697:Methane / Q000096:biosynthesis*; D054813:Polyhydroxyalkanoates / Q000494:pharmacology*; D012037:Refuse Disposal / Q000379:methods*; D012722:Sewage / Q000737:chemistry*; D012995:Solubility; D014835:Volatilization; D014866:Waste Products; D018508:Water Purification
chemical_list: D054813:Polyhydroxyalkanoates; D012722:Sewage; D014866:Waste Products; D008697:Methane