title: Efficient polyhydroxyalkanoate (PHA) accumulation by a new continuous feeding mode in three-stage mixed microbial culture (MMC) PHA production process.
abstract: A new continuous feeding mode was developed to optimize the polyhydroxyalkanoates (PHAs) accumulation step in the three-stage PHAs production process by mixed microbial cultures (MMCs) using mixed volatile fatty acids (VFAs) as substrate. The continuous feeding assays under low biomass loading rate (BLR) (in the range of 3.5-5.5Cmol VFA/Cmol X/d) can be directly fed with feedstock with pH from 5.0 to 10.0 without any pH regulation. The maximum intracellular PHA content of 70.4% and system PHA yield (YPHA/S(sys)) of 0.81Cmol PHA/Cmol VFA were achieved under the continuous feeding mode at BLR of 3.86Cmol VFA/Cmol X/d when directly fed with substrate at pH 5. These values were higher than those under the pulse wise feeding mode with the same substrate and active biomass concentration. The results indicated that a self-balanced pH state was formed in the continuous feeding system. Further studies on the reaction pH and kinetics of the MMCs in the continuous feeding reactor were conducted to understand the pH variation mechanism and accumulation process. The optimal BLR to get high PHA content and YPHA/S(sys) was 3.5-5.5Cmol VFA/Cmol X/d.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Long
authors.initials: L
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: wqxshelly@263.net.
authors.forename: Qinxue
authors.initials: Q
authors.lastname: Wen
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Zirui
authors.initials: Z
authors.lastname: Guo
mesh_terms: D001419:Bacteria / Q000254:growth & development* / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000379:methods*; D018533:Biomass; D019149:Bioreactors; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D059013:Microbial Consortia; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis*; D062065:Wastewater / Q000382:microbiology
chemical_list: D005232:Fatty Acids, Volatile; D054813:Polyhydroxyalkanoates; D062065:Wastewater
keywords: Biomass loading rate (BLR); Continuous feeding; Mixed microbial cultures (MMCs); Polyhydroxyalkanoates (PHAs); System PHA yield