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ABSTRACT: The successful application of bioaugmentation is largely dependent on the selective enrichment of culture with regards to pH, temperature, salt, or specific toxic organic pollutants. In this study, we investigated the effect of dissolved oxygen (DO) concentrations (aerobic, >2 mg L(-1); microaerobic, <1 mg L(-1)) on yeast enrichment culture for bioaugmentation of acidic industrial wastewater (pH 3.9-4.7). Clone library analyses revealed that the yeast community shifted in response to different DO levels, and that Candida humilis and Candida pseudolambica were individually dominant in the aerobic and microaerobic enrichment cultures. This would significantly influence the isolation results, and further hinder bioaugmentation due to differences in DO environments during the enrichment and application periods. However, differences in the selective enrichment culture cannot be predicted based on differences in pollutant removal performance. Thus, DO concentrations (aerobic/microaerobic) should be considered a secondary selective pressure to achieve successful bioaugmentation.
Bioresource technology 06/2012; 120:1-5. · 4.25 Impact Factor
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ABSTRACT: This paper developed a novel strategy to improve the fluorescence in situ hybridization-flow cytometry (FISH-FCM) enumeration performance in filamentous yeast species in activated sludge by snailase partial digestion to fully disaggregate filamentous yeast chains into single cells. A 2 h 2% snailase partial digestion liberated more rod-shaped yeast single cells from intertwined filamentous yeast samples than did sonication disaggregation, based on an optical microscopic observation and the forward-light-scatter frequency histogram of FCM analysis. However, adding snailase resulted in a fluorescence-quenching phenomenon of the hybridized filamentous yeast cells, which was minimized by lowering the snailase concentration. An approximately 3 h 0.5% snailase partial digestion conducted between sonication and hybridization significantly improved the FISH-FCM enumeration performance for filamentous yeast species by 37%. The results presented here will facilitate the rapid detection, identification and exact enumeration of specific filamentous fungal species in environmental samples.
Yeast 03/2012; 29(3-4):111-7. · 1.89 Impact Factor
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ABSTRACT: This study was conducted to compare the effect of influent chemical oxygen demand (COD(in)) level and hydraulic retention time (HRT), two primary components of influent COD loading rate (COD(LR)), on the structure and function of sludge microbial community in a yeast-predominant activated sludge system (1m Hx0.2m D) for synthetic industrial wastewater. A combination of polymerase chain reaction-denaturing gradient gel electrophoresis with BIOLOG community-level physiological profiles was used. At higher COD(LR) and higher COD(in) and identical HRTs, more microbial species were supported and could metabolise a greater variety of carbon sources in the aerated column. Conversely, a shorter HRT at identical COD(in) supported fewer microbial species, which resulted in the metabolism of fewer carbon sources.
Bioresource technology 05/2010; 101(10):3463-5. · 4.25 Impact Factor
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ABSTRACT: A lab-scale continuous experiment was designed to investigate the effect of influent COD concentrations (11,000, 15,000, 30,000 mg/L) or hydraulic retention time (HRT 42, 25 h) on the microareobic treatment performance of simulated high-strength organic wastewater. The molecular microbiological technologies, including Fluorescent in-situ hybridization-Flow Cytometry (FISH-FCM), Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE), and Biolog-FF assay method, were used to detect the variation of microbial community in the aerated column during the four pseudo-steady-state periods. The yeast contents remained > 99.9% throughout the overall experimental periods according to FISH-FCM. Increasing influent COD concentration brought on a rising MISS (2.0-7.3 g/L) and a reduced specific COD removal rate [2.3-1.7 kg/(kg x d)], structural (PCR-DGGE)/metabolic (Biolog FF) diversity index values of fungal community in the aerated column had an increase of (2.05-2.19)/(4.42-4.45). Shortening HRT brought on a reduced MISS (7.3-6.0 g/L) and a rising specific COD removal rate [1.7-2.8 kg/(kg x d)], structural (PCR-DGGE)/metabolic (Biolog FF) diversity index values of fungal community had a decrease of (2.19-0.79)/(4.45-4.36). Increasing influent COD concentration or shortening HRT has an absolutely adverse effect on the microaerobic treatment performance and micro-ecology in the aeration column although either of them can increase influent COD loading up to a higher level.
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 11/2008; 29(11):3087-92.
