Biodegradation of methyl tert-butyl ether as a sole carbon source by aerobic granules cultivated in a sequencing batch reactor

Abstract

Aerobic granules efficient at degrading methyl tert-butyl ether (MTBE) were successfully developed in a well-mixed sequencing batch reactor (SBR). Treatment efficiency of MTBE in the reactor during the stable operations exceeded 99.8%, and effluent MTBE was consistently below 800 microg/L. The specific MTBE degradation rate was observed to increase with increasing MTBE initial concentrations from 25 to 400 mg/L, peaked at 18.2 mg-MTBE/g-VSS h, and declined with further increases in MTBE concentration as substrate inhibition effects became significant. There was a good fit between these biodegradation data and the Haldane equation (R (2) = 0.976). Microbial community DNA profiling was carried out using denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction amplified 16S rDNA. The aerobic granule was found to contain a wide diversity of microorganisms. More than 70% similarity among the samples in the time period examined indicated a highly stable microbial community as the reactor reached the stable operation.

Characterization of the bacterial communities of aerobic granules in a 2-fluorophenol degrading process

“…1. The number of DGGE bands per lane varied between 7 and 19, indicating a wide bacterial diversity within the granules, as previously reported [43], [48], [50], [51]. Some bands were common in almost all samples (e.g., bands S1 and S3), while others were only present in some sampling days (e.g., bands S4 and S5).

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“…The dendrograms showed that the bacterial communities remained fairly stable during operation of the granular sludge SBR. Previous studies on the microbial community of chloroanilines-, methyl tert -butyl ether- and tert -butyl alcohol-degrading aerobic granules have also reported stable microbial community [43], [50], [51], [52]. Emanuelsson et al [15] stated that xenobiotic substrates are responsible for the stability of the microbial community, as they may reduce the diversity of a given microbial community by exerting a selective pressure.…”

“…According to BLAST results, bacterial communities were composed of organisms affiliated with Actinobacteria (1/9), Nitrospirae (1/9), but mainly belonged to the Proteobacteria group (5/9), subclasses γ - , α - and β - Proteobacteria (3/9, 1/9, 1/9, respectively). Sequences belonging to this group have previously been retrieved from aerobic granules degrading chloroanilines, methyl tert -butyl ether, tert -butyl alcohol and simple carbon sources such as glucose, acetate and propionate [6], [16], [23], [24], [43], [47], [50], [51], [52]. Particularly, Pseudoxanthomonas sp., Xanthomonas sp., Rhizobales sp., Acidovorax sp., and Nitrospira sp., which were the closest relatives of the sequences from bands S1, S3, S4, S6, and S8, respectively, have been previously found in aerobic granules [3], [16], [24], [46], [47], [48], [52].…”

Biodegradation of Diethylketone by Penicillium sp. and Alternaria sp. – A Comparative Study Biodegradation of Diethylketone by Fungi

“…The main disadvantages of these conventional techniques are the emission of other gases (NO x ), which requires additional costs for the secondary treatment, generation of contaminated solid waste, low efficiency, excessive use of chemicals, too expensive from operational, maintenance and equipment perspectives [7,9]. Studies conducted by different authors demonstrated that biological treatments can replace the conventional techniques and involve lower investment, in terms of capital and operational costs, show a good operational stability and are environmental friendly as they lead to the formation of less and/or non-dangerous products [10][11][12][13][14][15][16]. The biodegradation process of hazardous compounds by microorganisms is extremely complex and may result from the combination of several factors such enzymatic degradation, binding by extracellular polymeric substances (EPS) or binding by functional groups present on the cell wall.…”

The essential roles of Adenosine Triphosphate (ATP) and ATP-associated cellular communication in aerobic granulation

“…The adapted granules were capable of complete TBA removal and contained a highly stable microbial population with low phylogenetic diversity belonging to Proteobacteria and the Cytophaga-Flavobacteria-Bacteroides (CFB) group. Zhang et al (2008a) and Zhang et al (2008b)…”