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Ding Z.-W.,Hefei University of Technology | Ding J.,Hefei University of Technology | Ding J.,Advanced Laboratory for Environmental Research and Technology | Fu L.,Hefei University of Technology | And 2 more authors.
Applied Microbiology and Biotechnology | Year: 2014

Interaction between denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (anammox) processes may play an important role in global carbon and nitrogen cycles. In this study, a coculture of denitrifying methanotrophs (DAMO archaea and DAMO bacteria) and anammox bacteria, initially sourced from the environment, was enriched with a supply of methane, nitrate, and ammonium. After a 4.5-month enrichment, simultaneous oxidation of methane and ammonium and reduction of nitrate were observed. The highest rate of nitrate reduction in the suspended DAMO culture was 4.84 mmol/L/day, and simultaneously, the highest ammonium removal rate was 4.07 mmol/L/day. Fluorescence in situ hybridization and analysis of 16S rRNA gene clone libraries revealed the coexistence of DAMO archaea, DAMO bacteria, and anammox bacteria. The development of anammox bacteria might reduce the enrichment time of DAMO microorganisms and promote the activity of DAMO archaea. The activity of the reactor fluctuated during the long-term operation, which might be caused by the formation of microbial clusters whereby DAMO archaea grew in aggregates that were surrounded by anammox and DAMO bacteria. This study is the first to demonstrate that it is feasible to establish a coculture of DAMO archaea, DAMO bacteria, and anammox bacteria from environmental inocula. © 2014, Springer-Verlag Berlin Heidelberg.

Yu L.,Advanced Laboratory for Environmental Research and Technology | Chen Z.-X.,Advanced Laboratory for Environmental Research and Technology | Tong X.,Anhui Agricultural University | Li K.,National University of Defense Technology | Li W.-W.,Hefei University of Technology
Chemosphere | Year: 2012

The degradation kinetics and micro-scale structure change of microcrystalline cellulose during anaerobic biodegradation were investigated. A modified Logistic model was established to properly describe the kinetics, which showed good fitness and wide applicability for cellulose degradation. A maximum degradation rate of 0.14gL -1h -1 was achieved after cultivating for 51.5h. This result was in good agreement with the scanning electron microscope and X-ray diffraction analysis. Channels of 400-500nm size started to occur on the crystalline surface of cellulose at around the inflexion time. Accordingly, the crystallinity significantly decreased at this point, indicating a degradation of the crystalline structure zones by anaerobic bacteria. This study offers direct morphological evidence and quantitative analysis of the biodegradation process of cellulose, and is beneficial to a better understanding of the cellulose degradation mechanism. © 2011 Elsevier Ltd.

Zhang F.,Anhui University of Science and Technology | Ding J.,Advanced Laboratory for Environmental Research and Technology | Zhang Y.,Anhui University of Science and Technology | Chen M.,Anhui University of Science and Technology | And 4 more authors.
Water Research | Year: 2013

Gasification of waste to syngas (H2/CO2) is seen as a promising route to a circular economy. Biological conversion of the gaseous compounds into a liquid fuel or chemical, preferably medium chain fatty acids (caproate and caprylate) is an attractive concept. This study for the first time demonstrated in-situ production of medium chain fatty acids from H2 and CO2 in a hollow-fiber membrane biofilm reactor by mixed microbial culture. The hydrogen was for 100% utilized within the biofilms attached on the outer surface of the hollow-fiber membrane. The obtained concentrations of acetate, butyrate, caproate and caprylate were 7.4, 1.8, 0.98 and 0.42g/L, respectively. The biomass specific production rate of caproate (31.4mmol-C/(L day g-biomass)) was similar to literature reports for suspended cell cultures while for caprylate the rate (19.1mmol-C/(L day g-biomass)) was more than 6 times higher. Microbial community analysis showed the biofilms were dominated by Clostridium spp., such as Clostridium ljungdahlii and Clostridium kluyveri. This study demonstrates a potential technology for syngas fermentation in the hollow-fiber membrane biofilm reactors. © 2013 Elsevier Ltd.

Lu Y.-Z.,Hefei University of Technology | Ding Z.-W.,Hefei University of Technology | Ding J.,Advanced Laboratory for Environmental Research and Technology | Fu L.,Hefei University of Technology | And 2 more authors.
Water Research | Year: 2015

To develop universal 16S rRNA gene primers for high-throughput sequencing for the simultaneous detection of denitrifying anaerobic methane oxidation (DAMO) archaea, DAMO bacteria, and anaerobic ammonium oxidation (anammox) bacteria, four published primer sets (PS2-PS5) were modified. The overall coverage of the four primer pairs was evaluated in silico with the Silva SSU r119 dataset. Based on the virtual evaluation, the two best primer pairs (PS4 and PS5) were selected for further verification. Illumina MiSeq sequencing of a freshwater sediment and a culture from a DAMO-anammox reactor using these two primer pairs revealed that PS5 (341b4F-806R) was the most promising universal primer pair. This pair of primers detected both archaea and bacteria with less bias than PS4. Furthermore, an anaerobic fermentation culture and a wastewater treatment plant culture were used to verify the accuracy of PS5. More importantly, it detected DAMO archaea, DAMO bacteria, and anammox bacteria simultaneously with no false positives appeared. This universal 16S rRNA gene primer pair extends the existing molecular tools for studying the community structures and distributions of DAMO microbes and their potential interactions with anammox bacteria in different environments. © 2015 Elsevier Ltd.

Chu F.-F.,Advanced Laboratory for Environmental Research and Technology | Chu P.-N.,Hefei University of Technology | Shen X.-F.,Advanced Laboratory for Environmental Research and Technology | Lam P.K.S.,Advanced Laboratory for Environmental Research and Technology | And 3 more authors.
Bioresource Technology | Year: 2014

In order to study the effect of phosphorus on biodiesel production from Scenedesmus obliquus especially under nitrogen deficiency conditions, six types of media with combinations of nitrogen repletion/depletion and phosphorus repletion/limitation/depletion were investigated in this study. It was found that nitrogen starvation compared to nitrogen repletion enhanced biodiesel productivity. Moreover, biodiesel productivity was further strengthened by varying the supply level of phosphorus from depletion, limitation, through to repletion. The maximum FAMEs productivity of 24.2. mg/L/day was obtained in nitrogen depletion with phosphorus repletion, which was two times higher than that in nutrient complete medium. More phosphorus was accumulated in cells under the nitrogen starvation with sufficient phosphorus condition, but no polyphosphate was formed. This study indicated that nitrogen starvation plus sufficient P supply might be the real "lipid trigger". Furthermore, results of the current study suggest a potential application for utilizing microalgae to combine phosphorus removal from wastewater with biodiesel production. © 2013 Elsevier Ltd.

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