Biodegradation of Methyl Tert-butyl Ether in a Bioreactor using Immobilized Methylibium petroleiphilum PM1 Cells

Abstract

Methylibium petroleiphilum PM1, which is capable of degrading of methyl tert-butyl ether (MTBE), was immobilized in calcium alginate gel beads. Various applications were explored to increase the mechanical strength of these gel beads. The introduction of 0.3 mol/L calcium chloride into the crosslinking solution, 0.002 mol/L calcium chloride into the growth medium, and 0.2% polyethyleneimine (PEI) as chemical crosslinking agent increased the stability of the Ca-alginate gel beads under the operation conditions of the bioreactor. The degradation rates of MTBE by the immobilized cells in the bioreactor system operated in batch and continuous mode , respectively, were compared. A MTBE biodegradation rate of 5.79 mg/L·h was reached for over 400 h (50 batches), and the immobilized cells in the bioreactor removed >96% MTBE during 50 days of operation. Molecular analysis of the PM1 cells revealed that microbial growth occurred predominantly as microcolonies in the outer area of the beads during the first 20 days of operation. The results of this study show that a continuous-mode, fixed-bed bioreactor reactor coupled with PM1-immobilized cells is a promising technology for remediating MTBE-contaminated groundwater.

Successful treatment of an MTBE-impacted aquifer using a bioreactor self-colonized by native aquifer bacteria

“…In previous studies, MTBE mineralization has been linked to enrichment of native bacteria 96–99 % identical to M. petroleiphilum strain PM1 at an oxygen amended field site also located in southern California (Hristova et al 2003), in microcosms constructed from MTBE-contaminated aquifer sediments (Kane et al 2001), and in a GAC-based, bench-scale MTBE bioreactor (Pruden et al 2003). Immobilized M. petroleiphilum strain PM1 cells effectively removed 96 % of MTBE in a continuous-mode, fixed-bed bioreactor (Cheng et al 2011). 13 C labeled DNA with 99.7 % identity to M. petroleiphilum strain PM1 16S rRNA gene, as well as identities to genes in the proposed PM1 MTBE/TBA degradation pathway (Hristova et al 2007) was isolated in stable isotope probe (SIP) microcosm experiments utilizing GAC from active, TBA degrading bioreactors in New York and California (Aslett et al 2011).…”

Deposition and transport ofPseudomonas aeruginosain porous media: lab-scale experiments and model analysis

“…The reduction of bacteria attachment on the surfaces of porous media in the presence of a nonionic surfactant (Tween 20) has been reported for Alcaligenes paradoxus on beads and quartz sand [34][35][36] and Hydrogenophaga flava ENV735 on silica quartz sand. [37,38] …”

Calcium alginate beads reinforced with synthetic oligomers, linear polyethylenimine and Cu(II): structural stability and potential applications

“…The immobilization of enzymes, microorganisms, and plant and animal cells is carried out to protect them from environmental stresses, such as acid/alkaline conditions, chemical incompatibility, wet/dry cycles, and temperature changes in bioreactor systems for catalytic processes (Kurillova et al 2000;Kawaguti et al 2006;Cheng et al 2011;Xue et al 2013). Natural polysaccharides, such as alginate, low-methoxyl pectate, and chitosan, are usually selected to build gel beads by ionotropic gelation with Ca 2?…”

“…or K ? , requiring stabilization and hardening when used continuously in complex media of catalytic processes (Kurillova et al 2000;Kawaguti et al 2006;Cheng et al 2011;Xue et al 2013).…”

“…To overcome the limitations, a variety of polymers or functionalized macromolecules were added into the bead architecture, such as polyethylenimine hydrochloride (PEI.HCl) (Nussinovitch 2010). Alternative strategies have consisted of treating the preformed Ca(II)-alginate beads with the cross-linking polyethylenimine (PEI) followed by glutaraldehyde (GA) (Kurillova et al 2000;Kawaguti et al 2006;Cheng et al 2011;Xue et al 2013).…”