Functional analysis of microbial community in phenol-degrading aerobic granules cultivated in SBR

Phenol-degrading aerobic granules were cultivated in a sequencing batch reactor with an influent phenol concentration of 500 mg l−1. Eight strains were isolated from aerobic granules to characterize the functional redundancy of the microbial community in the granules. The specific oxygen utilization kinetics show the eight strains possessed different phenol-degrading activities, with half-saturation constants (Ks) ranging from 0.4 to 70.5 mg phenol l−1. Two isolates belonging to dominant populations expressed differing functions. The first strain was linked to the function of phenol degradation as this strain has the highest phenol-degrading ability among all isolates, while the second strain was linked to the maintenance of the granule structure because of its strong self-flocculation activity. This study could be used to exploit the granule-based system for treating high-strength wastewaters.

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Bacterial Diversity and Function of Aerobic Granules Engineered in a Sequencing Batch Reactor for Phenol Degradation

Applied and Environmental Microbiology ◽

10.1128/aem.70.11.6767-6775.2004 ◽

2004 ◽

Vol 70 (11) ◽

pp. 6767-6775 ◽

Cited By ~ 98

Author(s):

He-Long Jiang ◽

Joo-Hwa Tay ◽

Abdul Majid Maszenan ◽

Stephen Tiong-Lee Tay

Keyword(s):

Microbial Community ◽

16S Rrna ◽

Bacterial Diversity ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Phenol Degradation ◽

16S Rrna Genes ◽

Rrna Genes ◽

Aerobic Granules ◽

And Function

ABSTRACT Aerobic granules are self-immobilized aggregates of microorganisms and represent a relatively new form of cell immobilization developed for biological wastewater treatment. In this study, both culture-based and culture-independent techniques were used to investigate the bacterial diversity and function in aerobic phenol- degrading granules cultivated in a sequencing batch reactor. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes demonstrated a major shift in the microbial community as the seed sludge developed into granules. Culture isolation and DGGE assays confirmed the dominance of β-Proteobacteria and high-G+C gram-positive bacteria in the phenol-degrading aerobic granules. Of the 10 phenol-degrading bacterial strains isolated from the granules, strains PG-01, PG-02, and PG-08 possessed 16S rRNA gene sequences that matched the partial sequences of dominant bands in the DGGE fingerprint belonging to the aerobic granules. The numerical dominance of strain PG-01 was confirmed by isolation, DGGE, and in situ hybridization with a strain-specific probe, and key physiological traits possessed by PG-01 that allowed it to outcompete and dominate other microorganisms within the granules were then identified. This strain could be regarded as a functionally dominant strain and may have contributed significantly to phenol degradation in the granules. On the other hand, strain PG-08 had low specific growth rate and low phenol degradation ability but showed a high propensity to autoaggregate. By analyzing the roles played by these two isolates within the aerobic granules, a functional model of the microbial community within the aerobic granules was proposed. This model has important implications for rationalizing the engineering of ecological systems.

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Microbial community of aerobic granules for ammonium and sulphide removal in a sequencing batch reactor

Biotechnology Letters ◽

10.1007/s10529-012-0857-z ◽

2012 ◽

Vol 34 (5) ◽

pp. 883-888 ◽

Cited By ~ 4

Author(s):

Caili Su ◽

Lingfeng Zhu ◽

Chuan Zhang ◽

Xianghui Qi ◽

Yiping Guo ◽

...

Keyword(s):

Microbial Community ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Aerobic Granules

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The effect of intermittent feeding on aerobic granule structure

Water Science & Technology ◽

10.2166/wst.2004.0794 ◽

2004 ◽

Vol 49 (11-12) ◽

pp. 19-25 ◽

Cited By ~ 82

Author(s):

B.S. McSwain ◽

R.L. Irvine ◽

P.A. Wilderer

Keyword(s):

Sequencing Batch Reactor ◽

Batch Reactor ◽

Critical Role ◽

High Load ◽

Aerobic Granules ◽

Granule Formation ◽

Intermittent Feeding ◽

Granule Structure ◽

Growth System

Self-immobilized biofilms, or aerobic granules without the addition of carrier material, have only been reported in one suspended growth system, the Sequencing Batch Reactor (SBR) with a very short fill time (dump fill). The SBR utilizes intermittent feeding which creates a period of high load followed by starvation (often referred to as feast-famine). In this experiment, three identical SBRs were operated with different feeding conditions to determine the role of feast-famine on granule formation. All three SBRs were operated with a total volumetric load of 2.4 kg/m3·d. The 90 minute Fill phase was altered for each reactor, providing an increasing time of Aerated Fill. A dump fill condition was applied for one reactor, while the other two reactors were aerated for different times during Fill, resulting in a smaller COD load at the beginning of each React phase. Aerobic granules formed in all reactors, but the structural properties and content of filamentous organisms were clearly dependent on a high feast condition. Only the reactor with dump fill formed compact, stable granules. It is concluded that intermittent feeding associated with the SBR affects the selection and growth of filamentous organisms and has a critical role in granule structure and composition.

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