title: A systematic selection of the non-aqueous phase in a bacterial two liquid phase bioreactor treating alpha-pinene.
abstract: A systematic evaluation of the selection criteria of non-aqueous phases in two liquid phase bioreactors (TLPBs), also named two-phase partitioning bioreactors (TPPBs), was carried out using the biodegradation of alpha-pinene by Pseudomonas fluorescens NCIMB 11671 as a model process. A preliminary solvent screening was thus carried out among the most common non-aqueous phases reported in literature for volatile organic contaminants biodegradation in TLPBs: silicon oil, paraffin oil, hexadecane, diethyl sebacate, dibutyl-phtalate, FC 40, 1,1,1,3,5,5,5-heptamethyltrisiloxane (HMS), and 2,2,4,4,6,8,8-heptamethylnonane (HMN). FC 40, silicone oil, HMS, and HMN were first selected based on its biocompatibility, resistance to microbial attack, and alpha-pinene mass transport characteristics. FC 40, HMS, HMN, and silicone oil at 10% (v/v) enhanced alpha-pinene mass transport from the gas to the liquid phase by a factor of 3.8, 14.8, 11.4, and 8.6, respectively, compared to a single-phase aqueous system. FC 40 and HMN were finally compared for their ability to enhance alpha-pinene biodegradation in a mechanically agitated bioreactor. The use of FC 40 or HMN (both at 10% v/v) sustained non-steady state removal efficiencies (RE) and elimination capacities (EC) approximately 7 and 12 times higher than those achieved in the system without an organic phase, respectively. In addition, preliminary results showed that P fluorescens could uptake and mineralize alpha-pinene directly from the non aqueous phase.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, University of Valladolid, Valladolid, Spain.
authors.forename: Raúl
authors.initials: R
authors.lastname: Muñoz
authors.forename: Martin
authors.initials: M
authors.lastname: Chambaud
authors.forename: Sergio
authors.initials: S
authors.lastname: Bordel
authors.forename: Santiago
authors.initials: S
authors.lastname: Villaverde
mesh_terms: D000081008:Bicyclic Monoterpenes; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002245:Carbon Dioxide / Q000378:metabolism; D005285:Fermentation; D007220:Industrial Waste; D039821:Monoterpenes / Q000378:metabolism*; D010101:Oxygen Consumption; D044367:Phase Transition; D011551:Pseudomonas fluorescens / Q000378:metabolism*; D012997:Solvents / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D018675:Toxicity Tests
chemical_list: D000081008:Bicyclic Monoterpenes; D007220:Industrial Waste; D039821:Monoterpenes; D012997:Solvents; D002245:Carbon Dioxide; C005451:alpha-pinene