Biomedical subjects

Nan-Qi Ren

Publications and source records attributed to Nan-Qi Ren.

9 recordsLinked to original sources

PubMed2007

Degradation of phenol by aerobic granules and isolated yeast Candida tropicalis.

Aerobic granules effectively degrade phenol at high concentrations. This work cultivated aerobic granules that can degrade phenol at a constant rate of 49 mg-phenol/g x VSS/h up to 1,000 mg/L of phenol. Fluorescent staining and confocal laser scanning microscopy (CLSM) tests demonstrated that an active biomass was accumulated at the granule outer layer. A strain with maximum ability to degrade phenol and a high tolerance to phenol toxicity isolated from the granules was identified as Candida tropicalis via 18S rRNA sequencing. This strain degrades phenol at a maximum rate of 390 mg-phenol/g x VSS/h at pH 6 and 30 degrees C, whereas inhibitory effects existed at concentrations >1,000 mg/L. The Haldane kinetic model elucidates the growth and phenol biodegradation kinetics of the C. tropicalis. The fluorescence in situ hybridization (FISH) and CLSM test suggested that the Candida strain was primarily distributed throughout the surface layer of granule; hence, achieving a near constant reaction rate over a wide range of phenol concentration. The mass transfer barrier provided by granule matrix did not determine the reaction rates for the present phenol-degrading granule.

Aerobiosis↗

PubMed2006

[Common problems in the analyses of microbial community by denaturing gradient gel electrophoresis (DGGE)].

Denaturing gradient gel electrophoresis (DGGE) can describe microbial communities based on partial sequences of nucleic acid and monitor uncultured bacterium and it's functional genes. It is well-established molecular tools in microbial molecular ecology that allows the study of diversity and dynamics of microbial communities. Here, common issues in the analyses of microbial community by DGGE were raised, and the feasible resolving methods were introduced in this paper. The effects of samples pretreatment and PCR amplification on DGGE analysis were evaluated. Optimization and statistical analysis of DGGE profiles were discussed. Finally, prospect of DGGE for understanding microbial communities were reviewed.

Bacteria↗

PubMed2006

[Effects of terminal products on hydrogen production by ethanol hydrogen-producing microflora].

The effects of terminal products on hydrogen production were conducted in continuously stirred tank reactor (CSTR) by the acclimated ethanol hydrogen-producing bacteria. Glucose was added as carbon source and different ambient pH was carried out by buffer solution. High ethanol production was simultaneously achieved with high hydrogen production. The addition of 40 mol/L ethanol or acetic acid can result in the reduction of hydrogen production, the former was 34% and the latter was 84.3%. The ethanol fermentation formation for mixed microflora was attributed to the natural selection.

Bacteria, Anaerobic↗

PubMed2005

Molecular characterization and hydrogen production of a new species of anaerobe.

For the fermentative hydrogen production process with carbohydrates, isolation and identification of hydrogen-producing bacteria (HPB) with high yield and high evolution rate are very important. Improved Hungater rolling tube technique and plate method of culture bottle (PMCB) were used to enumerate and isolate the HPB. The HPB-Li and Ren (HPB-LR) medium was designed to inoculate and isolate HPB under temperature of 37 degrees C and pH of 4.0-6.7. In this study, an isolate of HPB with high yield and high evolution rate was isolated, named Rennanqilyf3 (R3), which is a gram-positive, straight rod, non-spore forming, encapsulated, strict anaerobe, with long peritrichous flagella and three to four metachromatic granules. It performs ethanol-type fermentation, and glucose is its optimum carbon source for hydrogen production. The 16S rDNA sequencing of the R3 isolate indicated that it might be a new species. The hydrogen production capacity of the R3 isolate varied with the glucose concentration and pH. The optimum glucose concentration was 12.0 g/L (with H2 yield of 58.6 mmolH2/L-culture) and the optimum initial pH was 5.5 (with H2 yield of 34.2 mmolH2/L-culture). The maximum rate of cell proliferation were 0.46 and 0.63 g/L when glucose concentration was 15.0 g/L and pH was 5.5, respectively. The maximum yields of ethanol and acetic acid were achieved when the glucose concentration was 12.0 g/L and the pH was 5.5.

Bacteria, Anaerobic↗

PubMed2005

[Full-scale two-phase anaerobic process treating traditional Chinese medicine wastewater].

A navel two-phase anaerobic-aerobic treatment technology was developed to treat high concentration and refractory organic wastewater discharge from Harbin Second Traditional Chinese Medicine Factory. The function of two-phase anaerobic process in the whole bio-treatment system was analyzed. Now the status in bio-technique of treating wastewater from traditional Chinese medicine production was that all the influent COD concentration was under 5 000 mg/L and its quality was easy to be bio-treated. The full-scale experiment has changed this status. Full-scale experiment results showed that when influent COD concentration was at 7 000 - 40 000 mg/L and its BOD5 /COD was lower than 0.2, the volume-loading rate and COD removal rate of acidogenic phase, a continuous-flow stirred tank reactor, could reach 20- 30 kg/(m3 x d) and 47.1% respectively. At the same time, it only took the mathanogenic phase 27 days to set-up. The volume-loading rate and COD removal rate of mathanogenic phase, an up-flow anaerobic sludge blanket-anaerobic filter reactor, could reach 6.0 - 7.0 kg/(m3 d) and 94.06% respectively. It was also demonstrated the COD removal rate of two-phase anaerobic process was over than 93.0%, which offer endurance for the effluent from the whole treatment system reaching relative standard performed in China.

Bacteria, Anaerobic↗

PubMed2005

[Microbial community structure analyzed by single-strand conformation polymorphism technique in sulfate-reducing reactor].

Analyses of microbial community structure and the relationships between Sulfate-Reducing Bacteria (SRBs) and Acidogenic Bacteria (ABs) in a completely stirred sulfate-reducing reactor were carried out by modified polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) targeted eubacterial 16S ribosomal RNA gene. A total of 13 bands were obtained and 6 of them (A1, A3, A4, A5, A9, A10) were sequenced. The sequences are similar to Leuconostoc mesenteroides (GenBank Access No. AY453065), some uncultured bacteria (AJ318147, AF227834, AJ576427), Ethanologenbacterium (AY434722), Clostridiaceae (AB084627), etc. In order to investigate the SRBs in the reactor,the active sludge was cultured on SRB-selected media and also did SSCP with the compound cultured bacteria. Two new bands appeared, one similar to Bacteroidetes (AB074606) and another similar to Desulfovibrio (Y12254, U42221). The experimental results indicate that the proportion of SRBs in the reactor is probably less than 1.5 percent. But the few SRBs play a very important role during the course of sulfate reduction via cooperation with acidogenic

Acids↗

PubMed2005

[Bioflocculant producing capability by two strains of Bacillus sp. in diversified carbon sources].

Two strains of Bacillus sp. F2 and F6 could produce bioflocculants with high flocculating effects by pure culture and mixed culture. Many kinds of carbon sources could be utilized. Organic compound which molecular weight under 200 such as saccharide, alcoholic aldehyde, ester and organic acid were favorable for producing bioflocculant. And some low-cost biomass scrap could be used as good carbon sources for industrialized production of bioflocculants, such as waste beet molasses, cellulose's fermentation residue and sewage of hydrogen producing reactor.

Bacillus↗

PubMed2004

[Isolation and characterization of new species hydrogen producing bacterium Ethanologenbacterium sp. strain X-1 and its capability of hydrogen production].

To obtain hydrogen-producing bacterium of high efficiency, a strain X-1 of hydrogen-producing bacteria was isolated from the continuous stirred-tank reactor (CSTR) by anaerobic Hungate technique. The Comparative sequence analysis of 16S rDNA showed that homology of strain X-1 with Clostridium cellulose and Acetanaerobacterium elongatum is less than 94%. All sequence alignment of 16S-23S rDNA intergenic spacer regions (ISR) indicated displayed that consensus region is tRNA(Ala), and tRNA(Ile), variable region is not homologous. Morphological, physic-biochemical character, and comparative sequence analysis of 16S rDNA and 16S-23S rDNA ISR indicated that strain X-1 belong to new genus named Ethanologenbacterium gen. nov.. Strain X-1 is facultative anaerobe bacillus; its main fermentative products are acetic acid, ethanol, H2 and CO2. The metabolic character of strain X-1 is typical ethanol type fermentation. Its capability of hydrogen production was measured in the batch culture experiment. X-1's maximum specific hydrogen producing rate is 28.3 mmol H2/( g dry cell x h) at pH 4.0 and 36 degrees C. Result of identify and analysis of hydrogen production ability demonstrated strain X-1 belong to new genus of high hydrogen-producing bacteria.

Ethanol↗

PubMed2004

[Application of denaturing gradient gel electrophoresis and temperature gradient gel electrophoresis in microbial molecular ecology].

In recent years, denaturing gradient gel electrophoresis (DGGE) and temperature gradient gel electrophoresis (TGGE) are well-established molecular tools in microbial molecular ecology that allows the study of diversity and dynamics of microbial communities. The technique is reliable, reproducible rapid and inexpensive. Here, the principle, the limitations and potentials application of DGGE/TGGE techniques are introduced in this paper.

Bacteria↗