The long-term effect of glutaraldehyde on the bacterial community in anaerobic ammonium oxidation reactor.

A 160-day incubation was performed with two anammox reactors (GA and CK) to investigate the effect of glutaraldehyde. The results indicated that anammox bacteria were very sensitive when glutaraldehyde in GA reactor increased to 40 mg/L, the nitrogen removal efficiency sharply decreased to 11%, only one-quarter of CK. Glutaraldehyde changed spatial distribution of exopolysaccharides, caused anammox bacteria (Brocadia CK_gra75) to disassociate from granules (24.70% of the reads in CK but only 14.09% in GA granules). Metagenome analysis indicated glutaraldehyde led to the denitrifier community succession from strains without nir (nitrite reductase) and nor (nitric oxide reductases) genes to those with them, and the rapid growth of denitrifiers with NodT (an outer membrane factor)-related efflux pumps replacing those with another TolC -related ones. Meanwhile, Brocadia CK_gra75 lacks the NodT proteins. This study provides important insight into community adaptation and potential resistance mechanism in an active anammox community after exposure to disinfectant.

[Isolation, Identification and Characteristic Analysis of an Oil-producing Chlorella sp. Tolerant to High-strength Anaerobic Digestion Effluent].

A Chlorella strain tolerant to high-strength anaerobic digestion effluent was isolated from the anaerobic digestion effluent with a long-term exposure to air. The strain was identified as a Chlorella by morphological and molecular biological methods, and named Chlorella sp. BWY-1, The anaerobic digestion effluent used in this study was from a biogas plant with the raw materials of swine wastewater after solid-liquid separation. The Chlorella regularis (FACHB-729) was used as the control strain. The comparative study showed that Chlorella sp, BWY-Ihad relatively higher growth rate, biomass accumulation capacity and pollutants removal rate in BG11. and different concentrations of anaerobic digestion effluent. Chlorella sp. BWY-1 had the highest growth rate and biomass productivity (324.40 mg.L-1) in BG11, but its lipid productivity and lipid content increased with the increase of anaerobic digestion effluent concentration, In undiluted anaerobic digestion effluent, the lipid productivity and lipid content of Chlorella sp. BWY-1 were up to 44. 43% and 108. 70 mg.L-1, respectively. Those results showed that the isolated algal strain bad some potential applications in livestock wastewater treatment and bioenergy production, it could be combined with a solid-liquid separation, anaerobic fermentation and other techniques for processing livestock wastewater and producing biodiesel.

Zymomonas mobilis: a novel platform for future biorefineries.

Biosynthesis of liquid fuels and biomass-based building block chemicals from microorganisms have been regarded as a competitive alternative route to traditional. Zymomonas mobilis possesses a number of desirable characteristics for its special Entner-Doudoroff pathway, which makes it an ideal platform for both metabolic engineering and commercial-scale production of desirable bio-products as the same as Escherichia coli and Saccharomyces cerevisiae based on consideration of future biomass biorefinery. Z. mobilis has been studied extensively on both fundamental and applied level, which will provide a basis for industrial biotechnology in the future. Furthermore, metabolic engineering of Z. mobilis for enhancing bio-ethanol production from biomass resources has been significantly promoted by different methods (i.e. mutagenesis, adaptive laboratory evolution, specific gene knock-out, and metabolic engineering). In addition, the feasibility of representative metabolites, i.e. sorbitol, bionic acid, levan, succinic acid, isobutanol, and isobutanol produced by Z. mobilis and the strategies for strain improvements are also discussed or highlighted in this paper. Moreover, this review will present some guidelines for future developments in the bio-based chemical production using Z. mobilis as a novel industrial platform for future biofineries.

Bamboo: a new source of carbohydrate for biorefinery.

Bamboo is perennial woody grass, which distributed widely in the world and belonged to the Gramineae family and Bambuseae subfamily. It may be consider as a candidate lignocellulosic substrate for bio-ethanol production for its environmental benefits and higher annual biomass yield. The conversion of bamboo into bio-ethanol, bio-methane, natural food, flavonoids, and functional xylo-oligosaccharides production were reviewed in this paper. Future prospects for research include pretreatment, enzymatic hydrolysis and fermentation will also be performed to improve the whole process of ethanol production more economical. And revealing the molecular regulation mechanism of the fast growth of bamboo will provide chance for improving bamboo or other energy plants biomass yield through genetic engineering.

Transcriptome profiling of Zymomonas mobilis under ethanol stress.

BACKGROUND: High tolerance to ethanol is a desirable characteristics for ethanologenic strains used in industrial ethanol fermentation. A deeper understanding of the molecular mechanisms underlying ethanologenic strains tolerance of ethanol stress may guide the design of rational strategies to increase process performance in industrial alcoholic production. Many extensive studies have been performed in Saccharomyces cerevisiae and Escherichia coli. However, the physiological basis and genetic mechanisms involved in ethanol tolerance for Zymomonas mobilis are poorly understood on genomic level. To identify the genes required for tolerance to ethanol, microarray technology was used to investigate the transcriptome profiling of the ethanologenic Z. mobilis in response to ethanol stress. RESULTS: We successfully identified 127 genes which were differentially expressed in response to ethanol. Ethanol up- or down-regulated genes related to cell wall/membrane biogenesis, metabolism, and transcription. These genes were classified as being involved in a wide range of cellular processes including carbohydrate metabolism, cell wall/membrane biogenesis, respiratory chain, terpenoid biosynthesis, DNA replication, DNA recombination, DNA repair, transport, transcriptional regulation, some universal stress response, etc. CONCLUSION: In this study, genome-wide transcriptional responses to ethanol were investigated for the first time in Z. mobilis using microarray analysis.Our results revealed that ethanol had effects on multiple aspects of cellular metabolism at the transcriptional level and that membrane might play important roles in response to ethanol. Although the molecular mechanism involved in tolerance and adaptation of ethanologenic strains to ethanol is still unclear, this research has provided insights into molecular response to ethanol in Z. mobilis. These data will also be helpful to construct more ethanol resistant strains for cellulosic ethanol production in the future.

Alternatively spliced transcripts of group 3 late embryogenesis abundant protein from Pogonatherum paniceum confer different abiotic stress tolerance in Escherichia coli.

The gene encoding a group 3 late embryogenesis abundant (LEA) protein was cloned from callus of the drought-tolerant grass Pogonatherum paniceum. Three alternatively spliced transcripts of this gene were amplified by RT-PCR. According to the bioinformatics analysis, the gene contained three exons and two introns. The PpLEA3.1 transcript which was the most abundant one in P. paniceum contained all three exons, and the PpLEA3.2 transcript lacked fragments of the first two exons which encoded a 41-amino acid-long region of the PpLEA3 protein. The PpLEA3.3 transcript retained the second intron. The three splicing patterns resulted in changes in the number of repeats of an 11-amino acid motif, hydropathy and the predicted 3-dimensional structure. When expressed in Escherichia coli, the three proteins differentially affected growth responses to salt, cold and heat stress. These results confirmed that the complete motif repeat structures and an appropriate hydrophilic/hydrophobic balance are important for the LEA protein in providing protection against various forms of stresses.

Transcriptome profiling of Zymomonas mobilis under furfural stress.

Furfural from lignocellulosic hydrolysates is the prevalent inhibitor to microorganisms during cellulosic ethanol production, but the molecular mechanisms of tolerance to this inhibitor in Zymomonas mobilis are still unclear. In this study, genome-wide transcriptional responses to furfural were investigated in Z. mobilis using microarray analysis. We found that 433 genes were differentially expressed in response to furfural. Furfural up- or down-regulated genes related to cell wall/membrane biogenesis, metabolism, and transcription. However, furfural has a subtle negative effect on Entner-Doudoroff pathway mRNAs. Our results revealed that furfural had effects on multiple aspects of cellular metabolism at the transcriptional level and that membrane might play important roles in response to furfural. This research has provided insights into the molecular response to furfural in Z. mobilis, and it will be helpful to construct more furfural-resistant strains for cellulosic ethanol production.

A flexible pro-porous coordination polymer: non-conventional synthesis and separation properties towards CO(2)/CH(4) mixtures.

The novel coordination polymers [Cu(Hoxonic)(H(2)O)](n) (1) and [Cu(Hoxonic)(bpy)(0.5)](n)1.5 n H(2)O (2 subsetH(2)O) (H(3)oxonic: 4,6-dihydroxy-1,3,5-triazine-2-carboxylic acid; bpy: 4,4'-bipyridine) have been isolated and structurally characterised by ab initio X-ray powder diffraction. The dense phase 1 contains 1D zig-zag chains in which Hoxonic dianions bridge square-pyramidal copper(II) ions, apically coordinated by water molecules. On the contrary, 2 subsetH(2)O, prepared by solution and solventless methods, is based on 2D layers of octahedral copper(II) ions bridged by Hoxonic ligands, further pillared by bpy spacers. The resulting pro-porous 3D network possesses small hydrated cavities. The reactivity, thermal, magnetic and adsorptive properties of these materials have been investigated. Notably, the adsorption studies on 2 show that this material possesses unusual adsorption behaviour. Indeed, guest uptake is facilitated by increasing the thermal energy of both the guest and the framework. Thus, neither N(2) at 77 K nor CO(2) at 195 K are incorporated, and CH(4) is only minimally adsorbed at 273 K and high pressures (0.5 mmol g(-1) at 2500 kPa). By contrast, CO(2) is readily incorporated at 273 K (up to 2.5 mmol g(-1) at 2500 kPa). The selectivity of 2 towards CO(2) over CH(4) has been investigated by means of variable-temperature zero coverage adsorption experiments and measurement of breakthrough curves of CO(2)/CH(4) mixtures. The results show the highly selective incorporation of CO(2) in 2, which can be rationalised on the basis of the framework flexibility and polar nature of its voids.

[DNA methylation-mediated regulation of OsMAPK2 gene expression in rice callus formation].

A DNA segment with DNA methylation site was detected from rice callus with or without 5-azaC treatment by MSAP. This segment was located on the first exon of gene OsMAPK2 and its 5' non-coding region. Gene OsMAPK2 had a CpG island in the 5' region and was homologous to AtMAPK12. Real-time quantitative PCR and Hpa II-McrBC PCR were conducted to detect the gene expression and DNA methylation of OsMAPK2 in the process of callus formation. The results showed that the DNA methylation was able to control the expression of OsMAPK2. The additon of 2.0 mg/L 2,4-D could induce DNA demethylation in the 5' region and activate the expression of OsMAPK2 gene. However, after long-time stimulation (100 h), the gene was methylated again, and the gene expression level was decreased. The trends of DNA methylation and gene expression stimulated by low concentrations of 2,4-D (0.5 and 1.0 mg/L) were similar to 2.0 mg/L 2,4-D, but the expression levels in each time point were low. On the other hand, high concentration of 2,4-D (5.0 mg/L) completed the processes of induction and suppression of the gene in a shorter time.

Manganese(II) pyrimidine-4,6-dicarboxylates: synthetic, structural, magnetic, and adsorption insights.

A series of manganese(II) coordination polymers containing the bridging ligand pyrimidine-4,6-dicarboxylate (pmdc) have been prepared. The stoichiometries and structural features of these materials, which range from the one-dimensional (1D) chains in ([Mn(mu-pmdc)(H2O)3].2H2O)n (1) and ([Mn2(mu-pmdc)2(H2O)5].2H2O)n (2) to the two-dimensional layers in ([Mn(mu3-pmdc)(H2O)].H2O)n (3) or the three-dimensional porous network in ([Mn(pmdc)].2H2O)n (4), are extremely dependent on the synthetic conditions (i.e., temperature and solvent). In spite of the structural diversity of these systems, crystallographic studies revealed that the pmdc ligand typically displays a tetradentate mu-(kappaO,kappaN:kappaO'',kappaN') coordination mode with the carboxylate groups almost coplanar with the pyrimidine ring [as in compounds 1 and 2 and compound 5 described below)]. In compound 3, the pmdc moiety adopts a pentadentate mu3-(kappaO,kappaN:kappaO'',kappaN':kappaO) coordination mode. The thermal, magnetic, and adsorption properties of these systems were also studied. The results showed that these compounds behave as antiferromagnets as a consequence of efficient magnetic exchange through the pmdc bridges. Compound 4 possesses permanent porosity, as proved by gas sorption data (N2 at 77 K and CO2 at 293 K). Finally, the heteronuclear iron(II)/manganese(II) compound ([FeMn(mu-pmdc)2(H2O)5].2H2O)n (5), which is isomorphous to 2, was also prepared and fully characterized.

[Effect of polyethylene glycol on the regeneration of the callus of Pogonatherum paniceum under different culture conditions].

This paper studied the effect of polyethylene glycol (PEG) on regeneration and free proline accumulation of callus of Pogonatherum paniceum (Lam.) Hack. under motionless liquid culture condition and shake liquid culture condition. Callus of P. paniceum had the ability to resist the stress of PEG. The effects of PEG stress and culture conditions on the callus of P. paniceum appeared mainly in two aspects, delaying regeneration time and debasing regeneration rates. The shake liquid culture mainly delayed the regeneration time and PEG stress mainly debased the regeneration rates. Free proline accumulated in the two culture conditions, and the contents of proline were positively correlated with PEG concentrations and culture time. After stress removal, most of the callus could recover the ability of regeneration, and the free proline might pay an important part in the inhibition and recovery. So it must be chosen a more than 300 g x L(-1) PEG concentration and long than 3 weeks culture time in the selection of drought-resistant mutants of P. paniceum. The motionless liquid culture was more suitable for selection of drought-resistant mutants.